METHOD AND APPARATUS FOR TESTING A PROGRESSION OF NEOPLASIA INCLUDING CANCER CHEMOPREVENTION TESTING

Abstract: A method and apparatus for the analysis of neoplasia in tissue and for pre-invasive cancer and for analysis of the effect of chemopreventive agents with respect to neoplasia. An interactive optical system (11a) acquires a plurality of abutting optical frames (413) along the basal layer (411) which are then imaged and digitized. A mouse is used to edit a reduced size mosaic (441) of the optical frames (433) in order to erase frames with limited analysis value. The mouse is also used to remove unwanted cell objects from full size frames (426). For each frame, area (505), sum optical density (507), run length (509), configurable run length (511), valley-slope-peak (513), coarseness (515), and Markovian textures (517) are analyzed and normalized, using mean and standard deviation, with respect to tissue taken from control subjects.

Description: METHOD AND APPARATUS FOR TESTING A PROGRESSION OF NEOPLASIA INCLUDING CANCER CHEMOPREVENTION TESTING Background of the Invention This invention relates to a method and apparatus for analysis of neoplasia in tissue and for pre- invasive cancer and for analysis of the effect of chemopreventive agents with respect to neoplasia. Currently, there are on-going chemoprevention programs that involve the routine testing of chemopreventive agents with the aims of using such agents to reduce the incidence of cancer by stopping the cancer progression or to regress the cancer. These programs desire to test a very large number of chemopreventive agents which occur naturally in foods or drinks or synthesized drugs for their efficacy. Currently, there are a number of centers that are testing chemopreven ve agents and that use pathologists to visually examine tissue and quantify the efficacy of these agents administered to animals or humans. These visual assessments are quite broad and are subjective and usually result in assessments such as nuclear grade, carcinoma in situ, preneoplastic intraepitheiiai neoplasia, etc. It will be appreciated that the limited ability of the human eye to make visual assessments ofter. requires the neoplasia to reach an advanced state in its evolution before it can be assessed. However, it is preferred to quantitatively evaluate the evolution of neoplasia in its early stage of evolution. The earlier the effective evaluation, the better chance of halting the progression of premalignant cells to the malignant state and the earlier that the effectiveness of possible chemopreventive agents can be determined. A number of benefits are obtained by an earlier evaluation of the effectiveness of a chemopreventive agent. First, a very substantial cost benefit results frcrr the ability to quantitatively evaluate premalignant tissue if done after an animal or person has been treated for ten to twenty weeks rather than to wait for the current thirty to forty weeks, which is often the case for visual evaluation by a pathologist. Further, if the 5 apparatus and methodology used are more sensitive or precise than those used by the pathologist, fewer subjects need to be tested. This reduces the cost of analysis with respect to a particular chemopreventive agent or subject, and allows for more analyses to be done 0 at any given testing facility in a given time frame. Of course, obvious health benefits accrue from earlier detection of a precancerous condition and the ability to monitor more quickly and more precisely the effectiveness of chemopreventive treatment for a given patient. 5 An article by Boone and Kelloff, entitled "Development of Surrogate Endpomt Biomarkers for Clinical Trials of Cancer Chemopreven ive Agents: Relationships to Fundamental Properties of Premvasive (Intraepithelial) Neoplasia", describes chemoprevention C as the prevention of clinical cancer by the administration of drugs or dietary constituents prior to or during the early phases of precancerous neoplasia, i.e., while the neoplastic process is still confined to the intraepithelial compartment and has not yet become Ξ invasive Boone and Kelloff describe tissue and cell changes and the need for the development of surrogate endpomt biomarkers (SEBs) , and divide the evolution of neoplasia as a continuum divided for convenience into five phases. In Phase I, genomic instability is present 0 an otherwise normal -appearing epithelium. In Phase II, clonal expansion of a mutated cell occurs. The individual cells are normal in appearance but crowded and disorganized pattern, with compression of the surrounding normal cells. This is the classic benign 5 epithelioma (aberrant crypt foci of the colon are an example). In Pnase III, the ceils develop abnormal morphology (described m detail below) . Phase IV is arked by invasion, the classic criterion by which pathologists make the diagnosis of cancer; and in Phase V, there is wide-spread dissemination. The ideal SEB should detect early changes during the intraepithelial neoplastic period and should monotonically increase in magnitude with neoplastic growth. The present invention is directed to providing a method and apparatus to assay cellular or tissue changes associated with the early neoplastic process, i.e., Stages I, II or III, prior to invasiveness and to be useful for many different tissue types, e.g. breast tissue, colon tissue, prostate tissue, esophageal tissue, skin tissue, cervix tissue, etc. for animals as well as for humans. One problem with assaying such a variety of tissues is a determination of what measurements cr features are most relevant or robust for each given neoplasia m that tissue. The measurements that provide the highest discrimination will vary from one neoplastic tissue to another type of neoplastic tissue. It will be appreciated that the various tissue types described above, suc.i as breast tissue, colon tissue, prostate tissue, esophageal tissue, skin tissue, and cervix tissue have different morphologies, and they undergo different neoplaεias usually resulting from a cellular mutation rate as may be enhanced by a carcinogen or resulting from a cellular proliferation rate enhanced by sex hormones, irritant chemicals or inducerε from chronic infection. Currently, there are no good objective biomarkers for such diverse neoplasias that can be done using equipment. There is a need to develop highly discriminating tests or measurements. Additionally, the tests or measurements for neoplasia will be done on different types of animals and on humans and at different clinical sites. Further, the measurements are often made when the change in the neoplasia is quite small, such as when the neoplasia is incipient cr because sequential tests are performed at close time intervals to ascertain if the progression of neoplasia has been slowed, stopped or regressed. The neoplasias may have distinct appearances as do their respective tissues. To be highly discriminating for such diverse tissues and diverse neoplasias, there is a need for a system which performs highly discriminating measurements for each particular neoplastic tissue. It has been found that some measurements are very discriminating for some tissues neoplasias but not very discriminating for other neoplasias. Assuming that appropriate discriminating measuring techniques and data are found, there still is a problem of how to grade or report these diverse test results which are so disparate in form. That is, linear measurements, area measurements, density measurements, surface roughness or texture measurements are made in diverse units, scales and magnitudes; and there exists the problem of how to coherently combine these results into a common scale that will be meaningful, easily understood and easily interpreted by pathologiεts or clinicians. For example, it would be best if the common scale would be valid and useful for evaluating, for example, thirty (30) different agents for skin precancerous tissue, twenty (20) different agents for esophageal precancerous tissue, and fifty (50) precancerous agents for precancerous colon cancer. Thus, there is a need for a system where the results of the measurements are standardized and objective and are easily conveyed to clinicians and others and will provide them w th an understanding of a chronology of the effects of small treatment doses of one or more chemopreventive agents on precancerous tissue. Suinmarv of the Invention In accordance with the present inventicr. , a method and apparatus are provided for analysis of neoplasia in tissue at a very early stage as well as later stages of its progression and includes an easily understood reporting of the progression or regression of the neoplasia. The present invention provides a fast and cost-effective analysis of the efficacy of or lack of efficacy of chemopreventive agents with respect to 5 neoplasia This has been achieved by an objective analysis system that performs multi-parametric measurements of the morphological structure and texture of the tissue structure itself and correlates them to a simple morphological grading scale. Further, this IC analysis has been achieved by the determination of and the selective measurement of those features or attributes which are most discriminating for a given kind of neoplastic tissue to show the progression of neoplasia in the tissue It has been determined that certain tissue 15 texture measurements are more highly discriminating for certain neoplasias and that other tissue measurements are more discriminating for other neoplasias The present invention has determined which measurements are most highly discriminating for certain neoplasias in certain 0 tissues and allows a selection from a large menu of multi-parametric measurements for the respective different ones of the neoplastic tissues Further, th s invention provides a method of and apparatus for rapidly and automatically performing scanning and data 5 acquisitio n for these assays in a cost-effective mannei The present invention also relates to a method and apparatus for combining several diverse measurements results in different units and on different εcales into a valid, objective and common universal scale which is ' useful net only in grading a particular neoplasia in tissue but is also useful for grading other neoplasias in tissues analyzed with other discriminating measurements This common scale is relative to and self-adjusts to the respective normal morphology characteristics and 5 differing heterogeneity of different tissue structures In accordance with the present invention, a sound and universal morphological grading system has been devised to combine onto a common scale the various test results made of diverse tissue types, such as breast tissue, colon tissue, cervix tissue, etc. and on different types of animals and humans as well as with different 5 carcinogens or chemopreventive agents. That is, the present invention allows one to analyze and measure the texture of a particular tissue having neoplasia, with a number of test results in different units and one different scales and combine them into a common score on 0 a common scale. Also, the present invention provides a common scale and score for various neoplasias in different tissues and relates them to a common scale wherein their relationship to an invasive score can be easily understood. Stated differently, different test 5 measurements on different neoplasias may be plotted on tne same score or scale so that each neoplasia' ε progression or regression reiative to a premvasive state is easily understood. Such a common scale allows an objective comparison of one chemopreventive agent versuε : another chemopreventive agent, and between the efficacy of such agents on animal or human neoplastic tissue. In the preferred apparatus and embodiment of the invention, a field of tissue is scanned by a microscope, and the scanned images are digitized, displayed and 5 stored electronically. The stored tissue images are then optionally edited to isolate for analysis the basal layer and tissues evolving therefrom. The edited images are then measured for morphometric and texture features that are preselected as being highly discriminating for the C kind of neoplastic tissue being analyzed. The measurements may be performed on entire microscope fields of imaged cell objects or on individual cell objects of the fields. In accordance with another aspect of the 5 invention, the preferred analysis is achieved by performing texture and morphometry measurements on normal tissue of the kind under consideration and then performing the same morphometry and texture measurements on a second tissue which is usually known to be a neoplastic tissue or suspected to be a neoplastic tissue. Then, the mean and standard deviation for each normal tissue measurement are determined. The mean for the second tissue is subtracted and divided by the standard deviation of the normal tissue to provide an individual Z-scale morphometric score. Individual Z-scale scores are averaged to provide a final score for the second tissue that is hereinafter is called a "Morphometric Z- scale Score". By way of example only, the morphometric Z-scale score for invasive neoplasia would be about a 7 or 8 reiative to zero or about zero score for a normal tissue so that there is sufficient breath of scale to distinguish on the scale incipient neoplasias close tc zero and to distinguish small incremental changes in neoplasia as may occur subsequently to an application of an effective chemopreventive agent for a short period of time. On the other hand, the application of a highly carcinogenic or neoplastic enhancing agent may provide a widely differentiating morphometric Z-scale score over a short period of time. In the present invention, each of the various suspected neoplastic tissues from the skin, cervix, colon, breast, etc. may be examined using different morphometric and texture features which are more powerful or discriminating for that kind of tissue. Even though different features are measured for these diverse neoplastic tissues, the above-described normalizing allows the results of each assay to be scored on the same morphometric Z-scale, and automatically compensates for normial heterogeneity of different tissues. Referring now in greater detail to the illustrated embodiment of the invention, neoplastic tissue sections are cut on edge and stained; and a step of editing is done interactively by a person who views visually and edits 100 to 400 digitized tissue images. The magnification used by the microscope allows the detection of features that are not seen by the human eye without magnification; and the analysis is done using these magnified features. Because 100 to 400 high resolution images of a neoplastic tissue is too large for an ordinary monitor, it is preferred to decrease the magnification of the displayed image so that a large segment of suspected neoplastic tissue comprising many images can be seen at once by the operator. The operator may then edit the tissue image on the monitor to exclude muscle, debris and other cell images leaving the basal layer image and those tissue cell images evolving from the basal layer for the morphometric and texture analysis at the higher resolution. It has been found that the measurements and tests used and needed are those that discriminate more texture and more granules which appear in neoplastic tissue than appear in normal tissue. That is, the malignant cells have more dark granules and a more "clump- like" or clumpy appearance and also a more "coarse" appearance. By way of analogy, the coarseness may be thought of as a serrated edge of a saw blade that has teeth defined by a number of uniform size peaks and valleys with occasional larger teeth projecting above the uniformly-sized teeth. The measure of the number of such oversized peaks, the distance therebetween, the length of teeth slope, the depth of the valleys, and the height of the peaks provide data as to the abnormal morphology of the neoplasia. The present invention may use some conventional tests and measurements, such as area measurements and summed optical densities; but a number of other specialized tests have been developed to quantify texture. Some known "Markovian Texture" measurements may also be used. For the most part, the selection of which particular measurements will result in highly discriminating Z-scores is one cf trial and error. The preferred texture measurements are usually taken in orientation to the basal layer and will have adjustable threεholds set for a particular tissue. Typically, the teεt measurements used are selected from a 5 menu of as many as one hundred (100) test measurements; but usually include ten (10) or less test measurements which are defined hereinafter) selected from a group comprising area; summed optical densities; run lengths- configurable run length; valley, slope or peak; and 0 Markovian Textures. Brief Description of the Drawings FIG. 1 is a perspective view of an apparatus for assaying biological specimens embodying the present invention ; 5 FIG. 1A is a perspective view, having portions broken away, of an automatic optical input subsystem of the apparatus for assaying bioiogical specimens shown in FI . I ; FIG. 2 is a block diagram of the apparatus shown : m FIG. 1; FIG. 3 shows a slide holder and associated control equipment of the apparatus shown in FIG. 1 ; FIG. 4 is a block diagram view of focus and light control portions of the apparatus shown in FIG. I; 5 FIG. 5 is a plan view of a microscope slide with a tissue section placed thereon for use with the apparatus of FIG. 1; FIG. 6 shows a plurality of abutting image fields acquired for analysis; 0 FIG. 7 shows a monitor screen on which is presented a mosaic of field images at reduced magnification and one field image in the present acquisition magnification; FIGS. 8A and 8B illustrate an edit mode of Ξ operation for working with displayed image frames,- FIG. 9 shows a menu display for the selection of assays to be performed on digitized tissue samples; FIG. 10 shows a plurality of adjacent pixels to illustrate a run length assay; FIG. 11 shows a run length configuration setup screen with which run length analysis can be configured; FIG. 12 shows a valley-εlope-peak setup screen; FIG. 13 shows a Markovian Texture analysis setup screen; FIG. 14 shows the set of analyses used to evaluate human cervix tissue samples; FIG. 15 is a graph of average Z-scores measured from tissue sections taken from experimental animals over a period of 30 weeks; FIG. 16 is a graph of the correlation of Z- εcores of human cervical tissue sections having known levels of neoplasia, compared to normal; FIG. 17 is a flow diagram of the function performed by the scanning and analysis apparatus; FIG. 18 shows the Z-scores of tissue sections from experimental animals given different levels of chemopreventive agents; FIGS. 19A-B show a before and after distribution of one group of the experimental animal tissues of FIG. 18; FIGS. 20A-D illustrate the raster method of image frame capture, editing and presentation; FIG. 21 shows the raster method applied to human cervix tissue; FIGS. 22A-B illustrate an analysis example performed on rat esophagus tissue sections; and FIG. 23 illustrates an analysis example performed cn rat colon tissue sections. Detailed Description of the Preferred Embodiment The present embodiment assays tissue samples to identify a progression of neoplasia therein and is used with laboratory animals, such as rats, to test possible chemopreventive agents for efficacy. The embodiment is also used to identify early neoplasia in other populations, including humans, to provide early disease detection which can prompt early treatment. The neoplasia identification of the embodiment begins with a tissue sample which iε stained or otherwise prepared for microscopic examination. The tissue samples are prepared so that a basal layer and cells evolving therefrom are presented to the microscope objective. The microscopic examination is performed by automated apparatus such as that described in U.S. Patent No. 5,473,706 issued December 5, 1995. The automated apparatus acquires optical density data from the stained tissue sample in a plurality of image frames, each about 90x150 microns. The image frames of most interest are acquired along the basal layer of the tissue sample. Accordingly, when the basal layer iε relatively linear, the image frames are acquired in abutting fashion along the basal layer. When the basal layer iε more irregular, abutting image frames are acquired in successive raster-like rows to cover the area of the sample. The acquired data is digitized and stored for editing and analysiε. In an editing process, image frames which do not contain information helpful to the analyses are excluded in their entirety. Further, cell objects in selected image frames are erased and the remainder of the image frame is stored for later use. After image frame acquisition and editing the analysis of the data they contain begins. A plurality of morphometric and texture analyses, such as cell object area, optical density, optical density per unit area, run length, configurable run length, valley-slope-peak and Markovian, may be performed on the image frames. The particular analyses to be performed for each type of tissue are selected for that type of tissue to be indicative of neoplasia. As described in greater detail below, the selection of analyses may result in a different set of analyses being performed for different tissue samples. The analyses are performed on a per- image frame resulting in a measured quantity being stored for each analyzed image frame for each analysis performed. The analysiε on a per- image frame basis has been found to provide results which identify neoplastic growth more readily than measuring only selected cell objects. Imaσe Acquisition Apparatus With the multitude of different tests being performed with many having different units of measurement, analyzing the results is difficult. The present embodiment includes a data normalizing method for use m producing a morphological Z-score which uses a single number to represent the analysiε of a tissue sample. Examples are provided herein which show the efficacy cf the present embodiment to detect neoplasia. Tne preferred embodiment diεclosed herein is used for the assay of tissue sections for neoplasia. The tissue samples to be analyzed in the preferred embodiment are stained using the Feulgen technique for DNA which iε described in detail in United States Patent No. 4, 9c, 264, issued March 5, 1991 to Bacus which iε hereby incorporated by reference. Other types of staining such as Hematoxylin and Eosin or Papanicolaou may be used within the scope of the present invention, as can any stair, that enhances histological structure for images. The apparatus shown and described with regard to FIGS. 1-4 iε used in the preferred embodiment to acquire image frames of tissue sample data. This apparatus includes a two-color optical system to enhance the optical characteristics of stained tissue samples; although, analysis by a single color is used primarily herein to determine optical densities. An apparatus for assaying biological specimens, and embodying the present invention and generally identified by numeral 10 is shown m perspective view m FIG 1 and in block diagram form m FIG. 2. An interactive optical system 11a comprises an optical microscope 12, which may be of any conventional type, but m this embodiment, is a Riechart Diastar. An optical conversion module 14 is mounted on the microscope 12 to enhance the optically magnified image of cell samples viewed with the microscope 12. The optical conversion module 14, as may best be seen in FIG 2, includes a beam-splitting prism 80 which conveys approximately 90% of the light into optical conversion module 14 and passes the remaining 10% to a microscope eyepiece 76. The light transmitted into module 14 is fed to a dichroic beamsplitter 82 which reflects a portion of the light to a television camera 20 via a red filter 18 and a mirror 81 The remaining portion of the light is filtered by a d cr.roic beam-splitter 82 and fed to a television camera 26 through a green filter 24 The dichroic bearr- splitter 82 selectively passes light having wavelengths greater than approximately 560 nanometers to the filter 18 and having a wavelength of less than 560 nanometers to the filter 24 Thus, the dichroic beam-splitter 82 acts as a first color filter before the light reaches the color filters 18 and 24. Red filter 18 is a 620 ± 20 nanometer bandpass optical transmission filter which provides a high contrast image to the camera 20. As shown m FIG. 2, the camera 20 generates an NTSC image signal which is fee through an optical signal switch 90a to an image processor 90 of an image processor module 28 (FIG. 2) Green filter 24 is a 500 + 20 nanometer narrow oandpass optical transmission filter which provides a high contrast image to a camera 26 The camera 26 then feeds an NTSC image signal through the optical signal switch 90a to an image processor 92 Both of the image processors 90 and 92 contain analog to digital converters for converting the analog NTSC signals to a digitized 384 by 485 array pixel image. The center 256 by 256 array of pixels from this digitized image is then stored within frame buffers internal to the image processors 90 and 92. The visual image represented by the 256 by 256 array of pixels is referred to aε an image field. In the present embodiment a pixel has a height of approximately .34 micron and width of approximately .5725 micron, so that an image field represents approximately an 87.04 by 146.54 micron portion of the tissue section. Each of the image processorε 90 and 92 is a Model AT428 from the Data Cube Corporation, and includes six internal frame buffers. The image processors 90 and 92 are connected to a system bus 34 of a computer 32. The frame buffers of image processors 90 and 92 are mapped into the address space of a microprocessor 36 m computer 32 to provide easy access for image processing Additionally, an image monitor 30 is connected to image procesεcr 92 and displays a cell sample image field stored in a predetermined one of the frame buffers The storage cf an image field representation into the predetermined frame buffer is described later herein. The automatic optical conversion module llr>, aε may best oe seen in FIG. 2, includes a prism 80a which convey? the light into optical conversion module 14a. Tne lignt transmitted into module 14a is fed to a dichroic beam-splitter 82a which reflects a portion of the light to a television camera 20a via a red filter 18a and a mirror 81a. The remaining portion of the light is filtered by a dichroic beam-splitter 82a and fed to a television camera 26a through a green filter 24a. The dichroic beam-splitter 82a selectively passeε light having wavelengths greater than approximately 560 nanometers to the filter 18a and having a wavelength of leεs than 560 nanometers to the filter 24a Thus, the cichrc c beam-splitter 82a acts aε a first color filter oefore tne liσht reaches the color filters 18a and 24a Red filter 18a is a 620 + 20 nanometer bandpass optical transmission filter which provides a high contrast image to the camera 20a. As shown in FIG. 2, the camera 20a then generates an NTSC image signal which is fed through 5 the optical signal switch 90 to the image processor 90 of the image processor module 28 (FIG. 2) . Green filter 24a is a 500 ± 20 nanometer narrow bandpass optical transmission filter which provides a high contrast image to a camera 26a. The camera 26a then feeds an NTSC image 0 signal through the optical signal switch 90a to the image processor 92. The above-described apparatus accumulates image information at cameras 20 and 20a from red filters 18 and 18a and at cameras 26 and 26a from green filters 24 and 5 24a. The analysis performed herein uses primarily the image produced by the red filters 18 and 18a and converted by cameras 20 and 20a. As a result, a data acquisition having only the filters 18 and 18a with associated cameras 20 and 20a is sufficient for 1 performing analyses herein described. The microprocessor 36 of computer 32 is an Intel 80486 microprocessor which is connected to the system bus 34. The optical switch 90a, under control of the microprocessor 36, selects the signal from interactive 5 unit 11a or automatic unit lib to be fed to the image processors 90 and 92. A random access memory 38 and a read only memory 40 are also connected to the system bus 34 for storage of program and data. A disk controller 42 is connected by a local bus 44 to a Winchester disk drive C 46 and to a floppy disk drive 48 for secondary information storage. Advantageously, local bus 44 is connected to a moveable media bulk data drive 45 such as an optical write once read many times (WORM) drive for image field recording and retrieval. 5 A video conversion board 50, in this embodiment a VGA board, is connected to the system bus 34 to control an instruction monitor 52 connected to the VGA board 50. Operational information such as selection menus and reports of analysis are displayed on instruction monitor 52. A keyboard processor 54 is connected to the system bus 34 to interpret signals from a keyboard 56 connected 5 to the keyboard processor 54. Input signals to microprocessor 36 are also generated by a hand control drive (mouse) 13 having a control button 15. Signals from mouse 13 and its button 15 are conveyed to bus 34 via a mouse interface 17. A printer 58 is connected to 10 the system bus 34 for communication with microprocessor 36. The apparatus 10 also includes a joystick control device 13a of a type well known in the art. Signals from the joystick 13a are conveyed to buε 34 via a joystick interface 17a. i The automated image input subsystem lib of apparatus 10 performs automated X-Y slide positioning, image focusing, light intensity adjustment and light color balancing functions. The X-Y slide position controlling apparatus is shown in FIGS. 1, 1A, 3 and 4, and includes a slide holder 62a capable of holding eight microscope slides 101 through 108 in side-by-side relationεhip such that the upper surfaceε of the εlideε are substantially coplanar. Slide holder 62a, which is sometimes referred to as a flat bed carrier, is movably attached to the stage 65a of microscope objective 64a by means of a slide holder base 63a. The portion of slide holder 62a positionable with respect to microscope objective 64a is controlled by an X position stepper motor 110 and a Y position stepper motor 111 which are mechanically attached to base 63a. The stepper motors 110 and ill are of the type known in the art which respond to pulse signals from a slide holder position controller 60. The actual X and Y positions of the slide holder 62a are sensed by an X position sensor 68 and a Y position sensor 66, respectively, which substantially continuously report position information to slide holder controller 60. In the present embodiment the slide holder 62a, base 63a, and position sensors 66 and 68 including limit switches and numbered 110 and 111 comprise a commercially available unit from Marzhauser Wetzlar GmbH Model EK8B-S4 with Model MCL-3 control units. Responsive to appropriate stepper motor control signalε, the slide holder baεe 63a is capable of placing substantially all of each of slides 101 through 108 under the objective 64a. Slide holder position controller 60 is connected to system bus 34 by means of a communication path 61. Microprocessor 36, as discussed later herein, transmits commands to slide holder position controller 60 specifying an X and Y position to place under the microscope objective 64a. Slide holder position controller 60 responds to such commands by transmitting tc the X and Y stepper motors 110 and 111 the appropriate sets of pulse signals to move the slide holder 62a to the desired X-Y position. The actual position of slide holder 62a is checked by slide holder poεition controller 6C during and at the completion of movement. The εlide holder position controller 60 alεo maintains an internal record of the X and Y position of the slide holder 62a which internal record can be read by microprocessor 36 via buε 34 and communication path 61. The apparatus 10 alεo includeε a focus and light controller 73 which controlε the light intensity and color balance from the light source 84a, as well as the focus of the image field presented to microscope 12. Microprocessor 36 communicates with focus and light controller 73, via the system bus 34 and a communication path 74, to control the focus and light properties. FIG. 4 is a functional block diagram of focus and light controller 73 and its connection to objective 64a and to bus 34. The objective 64a includeε a focus εtεpper motcr 75a, which is controlled by focus and light controller 73 through the εtepper motor controller 73a to raise and lower the stage 62a, and thereby raise and lower the microscope slides 101 through 108 carried by slide holder 62a. Microprocessor 36 includes a focus routine which is periodically performed during tissue analysis. When the focus routine is entered, microprocessor 36 reviews a digital representation of an image field from the image processors 90 and 92, and issues a command to focus and light controller 73, to raise or lower the stage by a specified amount. Focus and light controller 73 responsively transmits to focus stepper motor 75a electrical signals to implement the requested stage movement. By continued checking of the quality of the image field and adjustment of the up and down position of the slide holder 62a, microprocessor 36 brings the upper surface of the slide under the objective 64a into focus. Microprocessor 36 also stores a target value for the light intensity which is to be maintained during tissue sample analyεiε. Thiε stored light intensity value iε used by microprocessor 36 in conjunction with an intensity function to regulate the intensity of light from light source 84a. When the intensity function of microprocessor 36 iε enabled, the light intensity as represented by image fields from image processors 90 and 92 iε determined. Any departure from the εtored target light intensity value is corrected by sending intensity control commands to focus and light controller 73 which responds thereto by controlling a voltage regulator to increase or decrease the voltage applied to light source 84a. Voltage regulator 83 may be, for example, a standard rotatable voltage regulator which is rotated by a stepper motor operating under the control of electrical εignalε from focuε and light controller 73. Acquisition of Imaσe Frames FIG. 5 shows a microscope slide 400 prepared for the evaluation of rat esophageal tissue for neoplasia. Tissue sections 401, 403, and 405 of the entire rat esophagus are taken and placed on the slide 40C. Alεo placed on the slide 400 is a control tissue sample 407 of, for example, rat liver cells about which the properties are well known and which can be used to calibrate the apparatus and the tests performed as is 5 known. The tissue sections 401, 403 and 405 are taken and placed on the slide in such a manner that the basal layer of cells is substantially continuously observable. FIG 6 showε a magnified portion of an esophageal tissue section such aε section 401. The tissue section 401 is IC an epithelial section having a basement membrane 411 with the basal layer of cells on one side 413 and supportive tissue cells on the other side 414 The basal layer of cells forms the inner layer of the esophagus and it is in tn s layer m which cells evolve to maintain the outer 15 εurface of the esophagus After the tisεue samples 401, 4C3, 405 and 407 are placed on slide 400 (FIG 5;, they are prepared with normal DNA Feulgen staining techniques m a manner m which all cell samples including the contrc_ cells 407 are stained by the same process After 0 staining, the tissue section is covered with a cover glass ana made ready for testing The slide 400 is mounted in one of the slide positions, e.g 102, of slide holder 62a which is, m turn, attached to base 63a so that slide 400 can be 5 positioned under the objective 64a The joysticK 13a is used tc control the position of slide 400 by controlling control unit 32 to energize motors 100 and 111 as previously discussed. The magnification of the microscope is set to 40X, corresponding to approximately C tne previously discussed .34 by 5725 micron pixel size, resulting in an image frame (256x256 pixels) of about 87 04 microns by 146.54 microns In the manner previously described, the instrument is focused and light intensity is adjusted automatically to predetermined 3 standardε The position of slide 400 is then adjuεted tc bring one of the esophageal tissue samples, e g 401, under the objective 64a and focus is again performed by the apparatus. The primary interest in the present analysis is the basal layer on side 413 of the basement membrane 411 and the cells evolving from the basal layer. In tissue samples such as the rat esophagus of FIG. 6, the basal layer is somewhat continuous and linear and a plurality of abutting optical frames, e.g. 417-422, are imaged and a digital representation of the optical density of each image frame is generated and stored. In an analysiε, between 100 and 400 such frame images along the basal layer are imaged and digitized. The digitized images represent the intensity of the light at each pixel on a linear scale represented by 8 bits. Thus, the stored image records the optical density of each of the 256x256 pixels in the image frame. After an image is digitized, it is εtored in an addressable location in the system memory for later recall . The set of εtored digital images make up the data used for later analyεiε. Alεo stored is a physical address of each optical frame on the tissue sample so that the whole image can later be reconstructed from the set of stored frame images . The individual digital valueε representing each pixel within each frame are also stored at individually addresεable locations. The selection of frames for imaging and storage may be done manually by an operator or automatically by the apparatus. In a completely manual operation, the human operator selects, by controlling the joystick 13a, each of the fields and marks them for digitizing. In a completely automatic system, the apparatus will image adjacent fields in an area identified as containing the basal layer or the apparatus could automatically follow the line of increased density (darkness) which represents the basal layer, producing a series of images as shown in FIG. 6. In a preferred image acquisition method, an operator firεt identifies generally the position of the basal layer by tracing it using the joystick. The apparatus records the X and Y coordinates of the traced line and after tracing, returns to digitize and store abutting frames along the recorded line. The image acquisition phase of the procedure may continue with an optional editing phase. In other cases, the editing phase is omitted and the analysis process continues on all of the acquired images. At the beginning of the editing phase, a mosaic of tiles representing the images from the data acquisition is presented to an operator on the video display 30. The mosaic is presented with accurate image frame alignment so that the image, although reduced in magnification, appears substantially the same as the original tissue samples. FIG. 7 shows a mosaic 431 of frame images of rat eεophaguε tissue as displayed on monitor 30. A particular frame, as indicated by rectangle 433 of the mosaic 431, has been selected for a magnified view. The magnified view of frame 433 is presented in a field 435 of the display screen 30. When a magnified field 435 is presented, the operator can click on an eraser icon 436 and enter an edit mode in which the displayed individual image frame can be modified. The selected frame can be deleted entirely from the analysiε, in which caεe it iε marked with an X on the moεaic aε shown at 437 and 439 in FIG. 7. The deleted frame may. for example, be one in which tne tissue sample is broken or distorted or which contains some other flaw to cause it to have limited analysis value. In the edit mode the operator can also delete selected cell objects from the stored digital image. When the edit mode is optionally entered, an erasing cursor 426 is presented on the magnified image as shown in FIG. 8A, which erasing cursor can be moved by the computer mouse 13. Aε the erasing cursor 426 is moved on the image, the digital value of any pixel displayed at a position crossed by the erasing cursor 426, is set to "0" and remains "0" after the cursor moves on Any object can be removed from the image field by the use of the erasing cursor. FIG. 8B shows the image field of FIG. 8A after the erasing cursor has been moved across the pixels of cell objects 423, 424 and 425 to 5 remove them. The edited image 8B replaces the image 8A in the mosaic 431 and for later analysis. The preceding example of mouse esophageal tissue (FIGS. 6-8) demonstrated the capture and editing of image frames by an operator identifying the relatively linear 0 basal layer and the apparatus producing a series of abutting images along the identified layer. The present apparatus can also be used to capture and edit images m cases where a relatively linear basal layer is not present The preferred embodiment can, at the operator's 5 requeεt, εcan and image tissue samples in a raster manner aε shown in FIG 20A mouse colon cross sections. In the rastei type scan the operator identifies the outer perimeter of the object to be scanned The apparatus recorαs the X and Y coordinate of the perimeter and then C Deginε the image capture and digitizing at the upper left and proceeds across the object, within the identified perimeter with abutting image fields When the rightmost perimeter is reached the apparatus drops down one row of images and proceeds to capture and digitize 5 abutting image fields from right to left and so on until the area within the identified perimeter is filled with aDuttmg image fields. After the area of image fields has been captured and digitized, the editing process begins on a per-image ' frame basis. As shown with X's m FIG. 20A, some image frames, e.g. 485, 486, are completely removed from analysis by deleting them After all unwanted image frameε have been deleted, the remaining image frames can ce individually selected and edited as described with 5 regard to FIGS 8A and 3 to remove unwanted cell objects Tne selection of an image field 488 for display at an increased magnification (FIG. 20D) and editing with the erasing cursor 426 is shown in FIG 20C. After all unwanted image frames have been deleted and unwanted cell objects removed from the remaining image frames, the individual image frames are presented on the display aε an edited sample mosaic as shown in FIG. 20B. After editing, analysis proceeds image frame by image frame. The raster scan technique for image capture and analysis is also useful for human cervix tissue samples as represented at FIG. 21. Imaσe Fraire Analysis After editing the displayed tissue sample, if selected, and storage of the edited image frames, analysis beginε by εelecting measurement from the displayed menu field 441 (FIG. 7) . When measurement begins, an image field morphology page (FIG. 9) is displayed for operator interaction. The particular analyses to be used for analysis of a given type tissue sample are selected to provide results which accurately and efficiently identify neoplastic growth. The selection of analyses is done by acquiring and analyzing many tissue samples of a given type with varying known degrees of neoplasia. The acquired image frames are then analyzed using various combinations of the tests discussed below and an assessment is made of which of the performed tests best identify neoplasia. After such "best" tests are identified for a particular tissue type, they become the standards for the identification of neoplasia in that tissue type. At the beginning of frame analysis, the previously εtored frames are individually evaluated and each pixel of the frame is compared to a predetermined threshold indicative of a meaningful value of optical density. The current value of any pixel more optically dense than the threshold is restored for that pixel and the εtcred optical density of any pixel which is less dense than the threshold is set to "0", representing no optical density. The comparison to the optical density threshold and setting of pixels to "0" removes potentially meaningless "clutter" from the image. Such 5 comparison with a threshold to remove clutter may alternatively be performed prior to the image analysis operation and may be performed on the original digitized image before storage. The particular analyses which have been C identified and are used for particular tissue type analyseε are discussed below, after description of the individual analyses available to the operator. The user can select at a point 443 of field 441 the measurement of the area in square microns which is a measurement of the 3 area of non "0" optical density pixels in the recorded image. The operator can select at a point 444, the sum optical density which iε the total of the density values of all pixels of the selected image frame. The average optical density can also be selected at a point 445. The 1 average optical density is the sum optical density of ail pixelε m the image frame, divided by the above identified area of non-zero pixels in the frame. For each cf the above analyses used, a value representing each measured quantity is stored m association with each z measured image frame. Image texture measurements are also used for anaiyεiε. For example, the meaεurement of run length can be selected at point 447. In the run length measurement, each no -removed frame of data, e.g. 433, iε analyzed by : comparing the optical density of each pixel (called the center pixel) with the optical density cf both its immediate left pixel neighbor and its immediate right pixel neighbor. When the value of the center pixel is different from both neighbor pixels, the center pixel is 3 counted and the analysis moves to the same comparison using the next pixel to the right as the center pixel . Alternatively, when the optical density cf one or both cf the pixels to the immediate left and right of the center pixel is the same as the center pixel, the center pixel is not counted and analysis proceeds using the pixel to the immediate right of the center pixel as a new center pixel. The analysis proceeds in raster-like rows across the frame, then down one pixel and across again until all pixels have been compared. After an entire frame of 256x256 pixels has been analyzed, the total number of counted center pixels is recorded for the frame and the procesε proceeds to the next image frame upon which run length is performed again. The result of the run length analysis is the total count of pixels as above counted for each frame εtored for the tissue sample. Thus, if 500 frames are run length analyzed 500 counts will be εtored, one being associated with each image frame. FIG. 10, which is used to demonstrate run length analysis, represents 6 pixels 447-452 arranged in a scanned row. In the example, pixels 447, 448 and 449 are of equal optical density, pixel 450 has an optical density different from pixels 447, 448 and 449 and pixels 451 and 452 are all of an equal optical density, which iε different from the optical density of pixels 447, 448, 449 and 450. When pixel 448 is the center pixel, its optical density will be compared with that of pixels 447 ana 4 in the run length test. Since the optical density is the same, no count is made and pixel 449 will be next chosen as the center pixel. Since pixel 449 is cf different optical density from its left and right neighbors 446 and 450, the pixel is counted and pixel 45C iε next selected as the center pixel. Again, a pixel will be counted when 450 is the center pixel since its optical density is different from pixels 449 and 451; thereafter, pixel 451 becomeε the center pixel. Pixel 451 is cf different optical denεity from pixel 45C, itε left neighbor, but it is equal to pixel 452, its right neighbor. Accordingly, no count is made for pixel 451. As can be seen, many comparisons and pixel selections are employed to analyze an entire 256x256 pixel field. A configurable run length analysis is another available analysis option. Configurable run length is similar to run length, but the operator has more control over the comparison of pixels and the direction of center pixel selection and comparison with other pixels. Upon selecting configurable run length from the FIG. 9 menu, a new menu shown in FIG. 11 is presented to allow the user to set parameters for the analysis. Entry of a sample size value at a variable entry field 454 allows the lengthening of the comparison distance from the center pixel. For example, entering the number 2 at field 454 results m the comparison of the center pixel with its two left side neighbors and its two right side neighbors. Counting of a pixel takes place only when the conditions exiεt among the center pixel and the defined neighbor pixels as defined by the preεet variables. A variable entry field 456 permits an operator to identify either a positive or a negative optical density difference threshold. The optical density difference threshold is the amount of optical density difference between the center pixel and a neighbor pixel which is considered the same density. When this number is positive, e.g., 02 OD, a center pixel will be counted when it is greatei than ltε left and right neighbors (defined by the εample size) by an optical denεity of .02 OD or more. Similarly, when the difference threshold is negative, e.g., -.02 OD, a center pixel is counted when it is less than ltε neighborε by .02 OD or greater. The previously described run length analysiε compares pixels in a horizontal scan row, then drops down to perform the same comparison on the next row, always comparing m a horizontal direction. The textures of various tissue types yield differing results depending on the orientation of the comparison direction. This is due in part to the shapes of the cell object of the image frame and the orientation of those cell objects. In the case of rat esophagus tissue it has been found that comparing along the general direction of the basal layer provideε best results. For analysis of a tissue sample as shown in FIG. 6, top-to-bottom projection is preferred. Configurable run length permits the operator to select the comparison direction to be horizontal, vertical or at a 45° angle from upper left or upper right to provide maximum advantage. The particular direction is selected by setting one or more projection variables by selecting from four input boxes 458. After adjusting variable entry fields 454 and 456 and selecting one or more projections at 458, the operator selects an OK button 556 and returns to screen 446 of FIG. 9. The configurable run length iε then performed and center pixelε are counted, which compare to their neighbors m the manner defined by the variables set uεing the screen of FIG. 11. At the conclusion of the configurable run length analysis, a count is stored for each analyzed image frame which iε the sum of all center pixels meeting the teεts eεtabiiεhed by the variableε. When more than one projection iε εelected, the result cf configurable run length analysis iε the sum of all counted pixels for all projections. Another texture analysis called valley-slope - peak can be selected to analyze the image frames of tissue samples. As with the preceding analyses, variables are adjusted to define this analysis. Upon selection of valley-εlope-peak a variable setting menu 461 (FIG. 12} is presented to the operator to define the analyεiε variables. In valley-slope-peak, a center pixel is compared with its immediate neighbor pixels in a direction selected at projection configuration 463. The available directions are left to right, upper left to lower right, top to bottom and upper right to lower left. When a center pixel is less than both of its adjacent neighbor pixelε by an amount equal to or greater than a valley difference threshold set at point 465, the center pixel is counted as a valley pixel. When a center pixel is less than the neighbor pixel to one side and greater than the neighbor pixel on the other side, by an amount selected at a slope difference threshold 467, the center pixel is counted as a slope pixel. Lastly, when the optical density of a center pixel is greater than both neighbor pixels by a peak difference threshold set at 469, the center pixel is counted as a peak pixel. As with the run length measurement, all pixels of a field are selected in the predetermined direction for the valley-εlope-peak tests and the various valley-slope-peak pixel counts are retained on a per- image frame basis as indicative of the texture of the image field. After a frame is analyzed, the process proceeds to valley-εlope- peak analysis of another image frame until all image frames of the sample are analyzed and all valleys, εlopeε and peakε have been counted and results recorded. The valley-εlope-peak countε are alεo used to define a result called coarseness which is defined as the slope count minus two times the peak count -valley count [Consensus = slope-2 (peak-valley) ] . When the operator εelectε the coarseness results, valley-slope-peak analysis is performed and at the conclusion of each image frame analysis, the coarseness is calculated from the valley, slope and peak counts from that image frame. A coarseness results is stored in association with each analyzed image frame . Markovian texture analysiε can be also selected aε an image field texture analysis of the tissue selection. The selection of Markovian textures on screen 446 causes a variable setting screen 473 (FIG. 13) to be presented to the operator. Screen 446 permits the operator to select up to 21 of the known Markovian texture analyses and to set variables to refine the selected analyses. The performance of the individual Markovian analyses is described in detail m the literature, such as Pressman, NJ: "Markovian analysis of cervical cell images", J. Histochem Cytochem 24:138-144, 1976. In Markovian analysiε, a histogram of 8 grey ranges iε created to count the optical density of pixels. The common technique for identifying the 8 grey level ranges, as deεcribed in the above Pressman article, is called floating equalization in which the pixels having the least and most optical density are first identified and the range between them is divided into 8 equal grey level ranges. The floating equalization bringε out the texture cf the analyzed sample but the actual optical density information is lost. The present Markovian analysiε allowε the operator to εelect a fixed equalization proceεs and to define the upper and lower boundarieε cf the fixed equalization range. Aε before, tne fixed range iε divided into 8 equal εized grey level ranges for an optical density counting histogram. The fixed equalization provides the usual reεultε from Markovian analyses but the actual optical density information is preserved. Additionally, the operator can adjust the step size of the performed Markovian analysis. Tne preceding has described the apparatus used tc acquire and digitize image frames of tissue sampleε, how image frames are edited and stored, and the typeε of analyses available to identify neoplasia. The following sets forth examples for the use of these tools in identifying neoplasia and using such identification to test possible chemopreventive agents and diagnosing possible cancers. One manner of testing chemopreventive agents uεeε rats which are treated with a carcinogen to develop a particular neoplastic growth and ultimately a carcinoma. A first group of the rats iε treated with a carcinogen, and a second group is then treated with the εame carcinogen and also with an expected chemopreventive agent while a third control group is not treated m any way. The effectiveness of the administered chemopreventive agents can then be evaluated by comparing the progression of neoplasia in the two treated groups versus the control group. The experiment is designed to sacrifice groups of animals at various time periods to assess neoplastic development. The present analysis permits early detection of the pre-cancerous conditionε, which greatly shortens the time required to assess the effectiveness of chemopreventive agents. Shortening the times is important because there are many compounds to test and shorter, more precise testing saves testing costε and identifies chemopreventive agents for possible uεe earlier than other analysis methods, such aε human visual tissue inspection or time to death from cancer or survival rateε. The present analysis is alεo uεed to evaluate tiεεue εampleε of animals, including humanε , for possible neoplasia, which can result m an early diagnoεis of pre- cancerous conditionε and can thuε greatly increase patient survival rates over later detection, posεibly after metastasis. The present analysis has been used tc analyze human cervix tiεεue εampleε to identify the extent of progression of early pre-cancerous conditions. The first example relates to the analysiε of rat esopnagus tissue for the growth of neoplasia and the use of detected neoplasia in the identification of chemopreven ive agents. FIGS. 22A and 22B comprise a diagrammatic representation of the analysis of rat esophaguε tissue. FIG. 22A includes a representation of a plurality of image frames K ^ through K acquired from a normal rat esophaguε tissue sample 501. A dotted line box 503 laoeled analyses is shown connected by illustrative arrows 502 to receive image data from image frame K_ . In the example, the analyses 503 are sequentially connected to receive εtored image frame data from all image frames K λ through K κ . The particular analyses shown in box 503 and discussed herein have been selected after detailed study to have significant value in the detection of neoplasia in rat esophagus tissue. After the analyses have been selected for use on a particular tissue type, such aε rat esophaguε, they become the standard for testing that tissue type. As previously described, the best results from the varied analyses performed are achieved when they are reported as a morphometric Z-score. The morphometric Z- score iε a normalizing of the results which useε a mean and εtandard deviation of analyses performed on normal tisεue. The analyεiε of normal tissue should be done using the same analyses aε are to be used for the analyεiε of neoplasia in suspected tissue. Determining the mean and standard deviation from normal tiεεue lε not a sequential step of each analysis but it is tc be performed before the results of the analysiε of suspected tisεue are normalized. Accordingly, for a given set of analyses the evaluation of normal tissue can occur once and the result εtored as a library for later use in normalizing resultε of εuspected tissue. Each image frame, e.g., K 2 , is evaluated by each of the 10 analyses 505-517 shown within the analyseε box 503, then the evaluation proceeds to perform the analyses on the next image frame. Each analysis, such as area analysis 505, of an image frame results in a result X : , K- for that analysiε and that image frame. The tests performed on each image frame of the tissue sample begin with Area 503, sum optical density 507 and run length 509 which are performed as previously described. A configurable run length 511 is also performed on each image frame. The configurable run length analysiε for rat esophagus tissue has a εtep size cf 1 pixel, a difference threshold of -0.60 OD and a prelection from top tc bottom. A valiey-slope-peak analysis 513 is also performed and has 3 analyεiε reεults X 5 ,K 2 ; X 6 ,K 2 and X 7 ,K 2 for the valley count, slope count and peak count, respectively. For the valley-slope-peak analysis the difference threεhold iε set to .01 OD and the projection is from left to right for all tests. In addition, an overall threshold of low = .08 OD to high = .229 OD is set. The results of the valley-slope-peak analysis are separately stored for later use and are also combined into a coarseness measurement by analysis 515. Finally, the Markovian texture analyses of difference entropy X 5 ,K 2 and triangular symmetry X 1C ,K 2 are performed. Both Markovian analyses use a step size of 8 pixels and a fixed equalization between .08 OD and .4 OD At the conclusion of the analyses 503 of the normal tissue sample, a set of 10 test resultε X- , K. ; through X_ C ,K,, existε for each of the N image frames analyzed. When, for example, 300 image frameε are analyzed, this yields 300 resultε for each of the teεtε 505-517. After all analyses have been completed on the normal tissue section 501 image frames, the mean M and standard deviation S must be calculated for each analysis for later use in normalizing the resultε gained from analysiε of εuspected neoplastic tisεue. In FIG. 22A the normal tisεue mean and standard deviation for the area analysiε are shown as M- and S ; , respectively, and the mean and standard deviation for the triangular symmetry Markovian analysis are shown as M 10 and S 10 , reεpectively . FIG. 22B represents the analysis of a suspected neoplastic rat esophaguε tissue section represented at 527 and having a plurality of acquired image frames L through κ . As previously described, the image frames are acquired and digitized and they are then analyzed using the same 10 analyses 505-517 shown in FIG. 22A and having the same variable settings. The results of these analyses are shown as Y- , h 2 through Y ι; , L : for the second image frame L ; . When the results of all 10 analyses Y- , L : through Y :c , L 2 have been computed and are εtored in association with a respective image frame, they are normalized using the mean M and standard deviation S computed for corresponding analysis of the normal tissue sample 501. More specifically, the results of the area analysis 505 for suspected neoplastic tissue yields a result Y ι , 2 for the second image frame L 2 . The result iε converted to a preliminary Z-score (Z' by subtracting Y , L 2 from the mean Mi identified for normal tissue and dividing the result by the standard deviation S : of the normal sample. Similarly, each test result is subtracted from the corresponding mean M through M 1C and the result divided by the respective standard deviation S ^ through S ι: cf normal tissue. Preliminary normalizing creates 10 values, Z' through Z' 1G , one for each different test performed on the same image frame. The 10 Z' values are averaged to result in the Z-score Z for the image frame. After a value Z i has been determined for each image frame, all of the image frame Z-scores Z λ are averaged to yield an overall Z-score for the tissue sample. This resulting Z-score can be accurately compared with the Z-scores of other tests, whether or not the tests were performed on the same tissue type. FIG. 15 iε a graph comparing the increaεing Z- scores over time of esophagus tisεue of rats induced by treatment with N-Nitrosomethylbenzlamine (NMBA) which cauεeε neoplaεia compared to a control population which was not treated with NMBA. At ten weeks into the trial the Z-score of the normal population ranges from +.5 to - 1.5, while the Z-score of the esophaguε tiεεue in NMBD- treated animals exhibiting neoplasia ranges from +1.0 to +4.5. At 20 weeks the control population exhibits a Z- score between 0 and 1, while the tissue from the esophagus of treated animals exhibits a Z-score from +3.5 to +6. At 30 weeks the control tissue exhibits a Z-score from 0 to -1.5, while the tested tissueε exhibit a Z- score of +3.5 to +10.5. From FIG. 15 it iε apparent that the tests performed show a substantial departure from the control group as early as 10 weeks into the trial, which departure increases markedly at 20 and 30 weeks. FIG. 14 represents the analyses performed to detect neoplasia in human cervix tissue samples represented at 530. As discussed with regard to rat esophaguε tissue, a set of analyses 503 useful in detecting neoplasia is performed on normal tissue samples and on εuεpected neoplastic tissue sections. For human cervix tissue a sum optical density 531 analysis and the slope test 533 make up the set. The slope analysiε iε performed with a difference threshold of .06 OD and projections in the direction of all 8 pixel neighborε. Both analyses are performed on normal tissue and a mean K and a standard deviation S is computed for each test. The same set of analyses are then performed on tissue suεpected to exhibit neoplaεia . The analysiε results of the suspected tissue are then normalized in the manner of the rat esophaguε tissue and the resulting Z-score is used tc repreεent the tissue sample. FIG. 16 is a graph of Z-scores obtained by analysis, in accordance with the preferred embodiment, of human cervix tisεue sections identified by pathology experts to be in progressive stages of neoplasia ranging from normal tissue through cervical intraepithelial neoplasia grade III (CIN III). In FIG. 16, the Z-scores of normal tissue range from -1 tc +1. The Z-scores of tissue of CIN I range from +1 to 42; the Z-scores of tissue of CIN II range from 0 to 46 and; the Z-εcoreε of tissue of CIN III range from 45.5 to +10. Clearly the apparatus and methodε of the preεent embodiment show increaεing Z-scores for increasing neoplasia. FIG. 23 represents the analyses performed to detect neoplasia in mouse colon tissue sections represented at 540. The analyεeε 503 performed on ouεe colon tiεεue consist of average optical density, valley and slope and the Markovian textures of sum average, sum variance, difference variance and product moment. The valley and slope analyses are each performed with a difference threshold of .01 OD and in all projections. The Markovian textures analyses are all performed with a step size of 1 pixel and a fixed equalization between the 5 values .08 OD and .70 OD. The efficacy of the present embodiment in identifying chemopreventive agents iε shown in the graph of FIG. 18. The results of testing three groups of rats for neoplaεia in accordance with the present embodiment 10 show differences in the group results based on dosage of phenethylisothiocyate (PEITC) , a likely chemopreventive agent. All groups were treated with NMSA in a manner to produce a likelihood of neoplasia, similarly to the groups shown in FIG. 15. The first group, shown by line 15 479, received no PEITC during the teεt and the result iε a nearly straight projected line for an average Z-score cf C at the inception of the test to an average Z-score of almost 7 at 20 weekε into the test. The second group (line 481) which received low doses of PEITC, exhibit an 20 average Z-score of approximately 42.5 at 10 weeks and an average S-sccre of approximately 43.25 at 20 weekε. The third group (line 483) which received a high doεage of PEITC exhibits an average Z-score of approximately +1.5 at 10 weeks and a reduction in Z-score to approximately 25 ^ .75 at 20 weeks. The test results can also be presented in a manner referred to as "with and without treatment" or "before and after" aε shown in FIGS. 19A-B. FIG. 19A shows the "without" or "before" image of teεt resultε 30 measured at 10 weeks after administration of a high dosage of NMBA without PEITC (line 479 of FIG. 18) and FIG. 19B shows the "with" or "after" image of test resultε measured at 10 weeks after administration of a high dosage of PEITC. The movement of the measured ** •"" distribution closer to the mean as iε already demonstrated by FIGS. 19A-B shows the improvements achieved by the use of the chemopreventive agent PEITC. In the above described embodiments, the analysis and computation of the Z-scores are performed by the computer 32 (FIG. 2) of the image analysis equipment. It should be mentioned that the accumulated image frame data may be stored on removable media or made available on a network, and the analysis and computation of the Z-scores may be performed on another computer system. That is, the analysis need not be performed by the data acquisition computer system. As an example, the image frame data may be collected on a first computer and interactively analyzed by an operator at a second computer. The operator may select fields individually, rather than by a scanning method. This may be desirable for εmail, hard to locate, neoplaεia lesions such as proεtate mterepithelial neoplaεia (PIN) lesions, where accumulation of results may occur at many distinct sites. FIG. 17 showε the functions of the analysis apparatuε. In a block 601 the analysis data is received by the apparatuε. The analysis data includes the digitized image frames as well as the resultε of the anaiyεiε of "normal" tiεεue samples. The digitized image frame may be already be stored in the apparatus when the anaiyεiε apparatuε is also the scanning apparatus, or the digitized images may be received from movable storage media or downloaded frorr a network. The analysiε reεultε from normal tissue may be entered from movable media or the keyboard 56. Block 603 represents the selection of analyses by an operator, aε represented in display screens 9, 11, 12 and 13 aε discusεed above. After the selections of analyεes, the apparatus, block 605, performs the requested analyses in the manner discussed above and the results are stored in the apparatuε. At the conclusion of measurements and analyses, the apparatus reads the stored resultε and the reεults for normal tissue and computes the Z-scoreε m block 607, aε discusεed with regard to FIGS. 14, 22A, 22B and 23. The results of measurements and analyses, including the Z-scores computed by the apparatus, are then presented to the operator in block 609. Examples of such presented results are shown, for example, in FIGS. 15, 16 and 18. The results can also be stored for digital presentation on movable media or via a network. The preceding description sets forth analysis apparatus and methods for use in identifying the development of preinvasive neoplasia. Also described are methods for evaluating possible chemopreventive agents and the use of the disclosed methods and apparatus in such evaluating. The present invention is not limited to the above embodiments but extends to cover other embodiments, not shown or described, but falling within the ambit of the appended claims .

Claims: hat Is Claimed Is: 1. A method of analyzing a tissue sample having a layer of tissue cells for pre-invasive neoplaεia, comprising the steps of: optically and microscopically scanning the tissue sample to provide a tissue sample image and electronically recording the tissue sample image representing the tissue sample; analyzing the tissue sample image using one or 0 more measurements selected from a group of morphometric and texture measurements predetermined to be indicative of the progresεion of pre-invasive neoplasia development in the tisεue sample; and providing the results of the analyzing step. 2. A method in accordance with Claim 1 including the εteps of : measuring morphometric features of tissue sample images in first unit values; measuring texture featureε of tissue sample 0 images in other units or scale values; and combining the measured units and scale values into a common scale. 3. A method in accordance with Claim 1 including the steps of : 5 optically and microscopically scanning normal tissue samples and analyzing these normal tissue samples using a combination of morphometric and texture measurements; and optically and microscopically scanning abnormal C tissue samples and analyzing these abnormal tissue samples uεing the same combination of morphometric and texture measurements as used for the normal tiεεue. 4. A method in accordance with Claim 3 including the steps of: determining the mean and standard deviation for the measurements of the normal tissue; and subtracting the mean for abnormal tissue measurements from the mean for the normal tissue measurements and dividing by the standard deviation. 5 A method in accordance with Claim 4 including wherein the recording step comprises recording morphometric scores on a graph with the morphometric scale on the ordmate and a time scale on the abscissa to illustrate any progression of neoplasia 6 A method m accordance with Claim 1 wherein the tissue includeε a basal layer of tissue cells and the analysis is for neoplasia, said method including the stepε of addressing a plurality of the tissue sample images adjacent the basal layer; orienting the addressed tissue sample images to form a combined, reconstituted image of a portion of the scanned tisεue sample; and editing the reconstituted image to delete portions thereof from the subsequent analysis. 7 A method m accordance with Claim 6 including the steps of: scanning the tissue sample at a first magnification resolution; and decreasing the resolution for the reconstituted image . 8. A method accordance with Claim 7 wnerem analysis of the tissue sample is performed at the f rεt magnification resolution. 9. A method in accordance with Claim 7 including the steps of: interactively viewing the recorded tissue sample images; and interactively editing to leave substantially only the basal layer of cells and cells evolving therefrom . 10. A method in accordance with Claim 6 wherein the editing step comprises: displaying a tissue sample image selected from the reconstituted image at a higher resolution than the reconstituted image; and erasing from the displayed tissue sample image, one or more portions thereof having limited analysis value. 11. A method in accordance with Claim 10 comprising replacing the selected image of the reconstituted image with the edited version cf the εeiected tissue sample image. 12. A method in accordance with Claim 1 including the step of selecting, from a menu of measurements, a first set of morphometric and texture measurements which are highly discriminating for the first precancerous tissue; and 5 selecting a second set of different morphometric and texture measurements which are highly discriminating for the second precancerous test. 13. A method in accordance with Claim 1 wherein the analyzing step comprises analyzing a tissue sample C image for a predetermined texture feature and the method compπseε : identifying a mean value of the reεult of analyzing normal tisεue imageε for the texture feature; determining the mean value of the result of analyzing the tissue sample image for the predetermined texture feature; subtracting the mean value identified for the particular texture feature of normal tissue from the mean value determined for the particular texture feature of the analyzed tissue sample image; and recording the result of the subtracting εtep. 1 . A method in accordance with Claim 13 comprising identifying the standard deviation of the results of analyzing normal tissue images for the predetermined texture feature and dividing the result of the subtraction εtep by the identified εtandard deviatio . 15. A method of Claim 1 compriεing presenting tne recorded resultε in a manner which normalizes the results cf different analyseε . 16. A method of analyεis of a tissue sample comprising the εtepε of: optically and microεcopically scanning the tissue sample tc provide a tissue sample image, and electrc cally recording the tissue sample image; measuring the tissue sample image with respect tc area ; measuring the tissue sample image with respect to optical density; measuring the morphological texture of the tissue sample image; analyzing the resultε of the meaεured area, optical densitieε and morphological texture of the tissue sample image to provide morphological data, * and providing the morphological data for an analysis of the tissue sample image. 17. A method of analysis in accordance with Claim 16 wherein the step of analyzing the texture of the tissue sample image comprises the step of measuring run length which includes an analysis of neighboring cells in the tissue sample image for optical densities above a predetermined threshold. 18 A method of analysis m accordance with Claim 17 wherein the tissue sample has a basal layer extending m a given direction; and making the run length configurable by analyzing neighboring cells in the given direction of the basal layer IS. A method in accordance with Claim 16 wherein the texture measuring step comprises making at least one of a valley, slope or peak measurement . 20. A method m accordance with Claim 19 wherein a coarsenesε measurement of the texture lε obtained by subtracting from the slope measurements, the peak and valley measurements. 21. A method m accordance with Claim 16 wherein the texture measuring step comprises the making of a Markovian Texture measurement . 22. A method m accordance with Claim 21 including the steps of analysiε of human cervix tissue sample images wherein the step of measuring morphological texture includes tne making of Markovian Texture measurements . 23. A method of analyzing a basal layer sample of tiεεue having cells evolving from the basal layer for neoplasia, said method comprising the steps of: optically and microscopically scanning the tisεue cells along the basal layer over a plurality of tiεsue sample fields to provide tissue sample images; analyzing the tissue sample images with respect to area and optical density; analyzing the tissue sample images with respect to texture by making measurements including the step of an analysiε of run length by examining adjacent, neighboring cell images with respect to values above or below a predetermined threshold; and providing the run length analysis for use in evaluation of neoplasia. 24 A method m accordance with Claim 23 including the εtep of configuring the run length to extend m the direction that the basal layer extends. 25. A method in accordance with Claim 23 including the step of analyzing adjacent tissue cells tc provide at least one of valley, slope and peak measurements . 26. A method in accordance with Claim 23 including the step of measuring the tissue cell imageε using a Markovian Texture anaiyεiε. 27. A method in accordance with Claim 23 for analysis of human cervix tissue including the steps of: measuring the summed optical densities from the cervix tisεue cell imageε; and measuring the slope between adjacent human cervix cell imageε. 28. A method in accordance with Claim 23 including the steps of: analyzing an animal tiεεue to provide discri m inating data comprising the steps of: easuring the average optical densities of the animal tissue cell images ; meaεuring the valley and εlope from adjacent cell images of the animal tissue; and measuring Markovian Textures of the animal cell images . 29. A method in accordance with Claim 23 wherein the texture measurements of animal tissue includes using at least one of the following steps: measuring the run length of adjacent animal tissue cell images; measuring the run length which iε configured in direction and the spacing between analyzed cell images; measuring the valley, slope and peak between adjacent cell images; measuring the coarseneεε which includeε the εtep of subtracting the peak and valley from the slope; and measuring Markovian Textures of the analyzed cell images. 30. A method in accordance with Claim 23 including the εtep of recording the resultε of the respective measurements in a manner which normalizes the results of the morphometric and texture analyses. 31. A method of analyzing tissue samples for pre-invasive cancer comprising the steps of: optically scanning the tissue sample at a plurality of non-overlapping tissue sample fields and electronically recording a high resolution tissue sample image representing selected fields; analyzing the tissue sample images using a combination of morphometric and texture analyεeε predetermined to be indicative of the progreεsion of cancer development; normalizing results of selected analyses performed in the analyzing step to a common standard; and deriving a value indicative of the progression of cancer development from the normalized results. 32. A method in accordance with Claim 31 including the step of editing the recorded tissue sample images to delete portions of the image not representing the basal layer and the evolving tissue cells to create edited tisεue sample images and wherein the analyzing step comprises analyzing the edited tissue sample images. 33. A method of analyzing the efficacy of a chemopreventive agent on first and second precancerous tissues, said method comprising the stepε of: optically and microscopically scanning the first precancerouε tiεεue and electronically recording a firεt tissue sample image representing the firεt tiεsue; analyzing the first tissue sample images using a first set of morphometric and texture features highly discriminating for the first precancerous tissue; optically and microscopically scanning the second precancerous tissue and electronically recording a second tissue sample image representing the second tissue ; analyzing the second tissue sample image using a second set of morphometric and texture features highly discriminating for the second precancerouε tissue; combining the morphometric and texture feature measurements from the firεt precancerouε tiεsue to a common scale; and combining the morphometric and texture feature measurements from the second precancerous tisεue to the εame common scale so that progreεsion of cancer of the first and second tissues can be compared on the same basis . 34. A method in accordance with Claim 33 wherein there is provided as first precancerous tissue a cervical tissue sample and wherein there is provided as the second precancerous tissue an esophageal tissue. 35. A method in accordance with Claim 33 including the step of taking sequentially in time the first and second precancerous tissue samples from the same part of the body and using thereon the first and second sets of morphometric and texture features for analyεiε. 36. A method in accordance with Claim 33 wherein the firεt and second precancerous tissueε are taken from first and second parts of a body. 37. A method m accordance with Claim 33 wherein the first and second precancerous tissues are taken from different animals. 38. A method in accordance with Claim 33 including the εtepε of analyzing the first and second precancerous tissue over a plurality of tissue fields. 39. A method in accordance with Claim 33 including the step of normalizing the measurements recording the scores on a scale that has plus and minus numbers below twenty (20) . 40. A method in accordance with Claim 33 including the step of measuring at least some of the firεt morphometric or texture featureε with εcaleε or units different from the scales or units used to measure the second morphometric or texture features. 41. A method in accordance with Claim 33 including the step of optically and microscopically scanning a plurality of tissue fields for each of the first and second tissue samples. 42. A method of analyzing the efficacy of an expected chemopreventive agent in animal model experiments comprising the steps of: treating a plurality of animals with the expected chemopreventive agent; extracting at least one first tissue sample from animals of the plurality of animals at a first time; extracting at least one second tisεue sample from animals of the plurality of animals at a second time, the second time being later than the first time by an amount significant in the progression of neoplaεia; analyzing the first and second tiεεue εampleε using a set of morphometric and texture features highly discriminating for an expected neoplaεia; and comparing the results of analysiε of the firεt and second tissue samples. 43. A method in accordance with Claim 42 wherein a control plurality of animals iε not treated with the expected chemopreventive agent and the method compriεes : extracting at least one tissue sample from the control plurality of animals,• analyzing the tissue samples from the control plurality of animals using a set of morphometric and texture features highly discriminating for an expected neoplasia; and comparing the results of analysis of the control animal tissue samples with the results of analyses of the firεt and εecond tiεεue samples. 44 A method in accordance with Claim 42 comprising the step of combining the morphometric and texture feature measurements of the first and second tissue εampleε to a common scale. 45. A method m accordance with Claim 43 comprising the step of combining the morphometric and texture feature measurements of the first, second and control tissue samples to a common scale. 46 A method of identifying a progression over time cf epitnelial neoplasia in a population of animals ^ ncluamσ humans comprising. extracting first epithelial tisεue samples fro ***** the population at a first time; extracting second epithelial tisεue samples froτ tne population at a second time later than the first time .oy an amount of time significant m the progression of neoplasia , optically and microscopically scanning the firεt tiεεue εample and the second tissue sample and electronically recording tisεue εample images; analyzing the tiεεue εample images using a combination of morphometric and texture analyses predeter m ined to be indicative of the progression of neoplasia in the tissue samples, determining from the analyzing εtep a first value indicative of epithelial neoplasia m the first tissue sample and a second value indicative of epithelial neoplasia in the second tissue εample; and comparing the first value and the second value 47 A method of analyzing the efficacy of an expected chemopreventive agent m animal model experiments comprising the stepε of : providing tiεsue samples taken from a control group of animals which have not been treated with the expected chemopreventive agent at predetermined time intervals ; providing tissue samples taken from an experimental group of animals which have been treated with an expected chemopreventive agent at predetermined time intervals; analyzing the respective tissue sampleε using at least one of morphometric or texture measurements of the respective tissue samples; and displaying the results of the analysis of the control group and the experimental group on a common scale versus time. 48 Apparatus for analyzing a tissue sample having a layer of tissue cells for pre-invasive neoplasia, comprising: scanning means for optically and microscopically scanning the tissue sample to provide a tissue sample image and for electronically recording the tissue sample image representing the tiεεue εample; meanε for analyzing the tissue εample image using at leaεt one morphometric and texture measurement predetermined to be indicative of the progression of premvasive neoplasia development m the tisεue sample; and meanε for providing the results of the analyzing step 49. Apparatus for analyzing cells comprising: scanning apparatus for optically and microscopically scanning the cells to provide cell imageε, and for electronically recording the cell imageε, meanε responsive to the recorded cell images for measuring the area of the cell images, for measuring the scanned optical densities of the cell images and for measuring the morphological texture of cell images; analyzing means responsive to the results of the measured area, optical denεitieε and morphological texture of the cell images for providing morphological data; and means for providing the morphological data for an analysis of the cells. 50. Apparatus in accordance with Claim 49 wherein the means for analyzing the texture of the cell comprises a means for measuring run length which includes an analysis of neighboring cells for optical densities above a predetermined threshold. 51. Apparatus in accordance with Claim 50 wherein the cells are part of a tissue sample having a basal layer extending in a given direction; and the meanε for measuring the run length is configurable to analyzing neighboring cells in the given direction of the basal layer. 52. Apparatus in accordance with Claim 49 wherein the means for measuring texture comprises means for making at least one of a valley, slope or peak measurement . 53. Apparatus in accordance with Claim 52 comprising means for measuring a coarseness of the texture by subtracting from the slope measurements, the peak and valley measurements. 54. Apparatus in accordance with Claim 49 wherein the means for measuring texture comprises means for making a Markovian Texture measurement . 55. Apparatus in accordance with Claim 54 wherein the analyzed cells are human cervix tissue cells imageε and the means for measuring morphological texture includeε means for the making of Markovian Texture measurements .

Inventors: BACUS JAMES V, BACUS JAMES W, BACUS, JAMES, V., BACUS, JAMES, W.
Applicants: BACUS RES LAB INC, BACUS RESEARCH LABORATORIES, INC.
Application year: 1997
Main classification: G06K9
IPC codes: G01N15, G06F19, G06T3, G06T7