Method and system for providing information from a patient-specific model of blood flow

Embodiments include a system for providing blood flow information for a patient. The system may include at least one computer system including a touchscreen. The at least one computer system may be configured to display, on the touchscreen, a three-dimensional model representing at least a portion of an anatomical structure of the patient based on patient-specific data. The at least one computer system may also be configured to receive a first input relating to a first location on the touchscreen indicated by at least one pointing object controlled by a user, and the first location on the touchscreen may indicate a first location on the displayed three-dimensional model. The at least one computer system may be further configured to display first information on the touchscreen, and the first information may indicate a blood flow characteristic at the first location.

FIELD

Embodiments include methods and systems for using models of fluid flow and more particularly methods and systems for providing information from patient-specific models of blood flow.

BACKGROUND

Coronary artery disease may produce coronary lesions in the blood vessels providing blood to the heart, such as a stenosis (abnormal narrowing of a blood vessel). As a result, blood flow to the heart may be restricted. A patient suffering from coronary artery disease may experience chest pain, referred to as chronic stable angina during physical exertion or unstable angina when the patient is at rest. A more severe manifestation of disease may lead to myocardial infarction, or heart attack.

Patients suffering from chest pain and/or exhibiting symptoms of coronary artery disease may be subjected to one or more tests that may provide some indirect evidence relating to coronary lesions. For example, noninvasive tests may include electrocardiograms, biomarker evaluation from blood tests, treadmill tests, echocardiography, single positron emission computed tomography (SPECT), and positron emission tomography (PET). The noninvasive tests may provide indirect evidence of coronary lesions by looking for changes in electrical activity of the heart (e.g., using electrocardiography (ECG)), motion of the myocardium (e.g., using stress echocardiography), perfusion of the myocardium (e.g., using PET or SPECT), or metabolic changes (e.g., using biomarkers). These noninvasive tests, however, do not predict outcomes of interventions.

For example, anatomic data may be obtained noninvasively using coronary computed tomographic angiography (CCTA). CCTA may be used for imaging of patients with chest pain and involves using computed tomography (CT) technology to image the heart and the coronary arteries following an intravenous infusion of a contrast agent. However, CCTA cannot provide direct information on the functional significance of coronary lesions, e.g., whether the lesions affect blood flow. In addition, since CCTA is purely a diagnostic test, it does not predict outcomes of interventions.

Invasive testing may also be performed on patients. For example, diagnostic cardiac catheterization may include performing conventional coronary angiography (CCA) to gather anatomic data on coronary lesions by providing a doctor with an image of the size and shape of the arteries. However, CCA also does not predict outcomes of interventions.

Thus, a need exists for a method to predict outcomes of medical, interventional, and surgical treatments on coronary artery blood flow.

SUMMARY

In accordance with an embodiment, a system for providing blood flow information for a patient may include at least one computer system including a touchscreen. The at least one computer system may be configured to display, on the touchscreen, a three-dimensional model representing at least a portion of an anatomical structure of the patient based on patient-specific data. The at least one computer system may also be configured to receive a first input relating to a first location on the touchscreen indicated by at least one pointing object controlled by a user, and the first location on the touchscreen may indicate a first location on the displayed three-dimensional model. The at least one computer system may be further configured to display first information on the touchscreen, and the first information may indicate a blood flow characteristic at the first location.

In accordance with another embodiment, a method for providing patient-specific blood flow information using at least one computer system including a touchscreen may include displaying, on the touchscreen, a three-dimensional model based on patient-specific data. The three-dimensional model may represent at least a portion of an anatomical structure of the patient. The method may also include receiving a first input relating to a first location on the touchscreen indicated by at least one pointing object controlled by a user, and the first location on the touchscreen may indicate a first location in the displayed three-dimensional model. The method may also include displaying first information on the touchscreen, and the first information may indicate a blood flow characteristic at the location in the three-dimensional model indicated by the first input. The method may further include receiving a second input indicating a modification of the three-dimensional model and determining second information regarding the blood flow characteristic in the anatomical structure based on the modification of the three-dimensional model.

In accordance with a further embodiment, a non-transitory computer readable medium for use on at least one computer system may contain computer-executable programming instructions for performing a method for providing patient-specific blood flow information. The at least one computer system may include a touchscreen, and the method may include displaying a three-dimensional model representing at least a portion of an anatomical structure of the patient based on patient-specific data and receiving a first input relating to a first location on the touchscreen indicated by at least one pointing object controlled by a user. The first input may indicate a location of a stent for placement in the anatomical structure. The method may also include displaying the stent on the three-dimensional model on the touchscreen and determining second information regarding a blood flow characteristic at a plurality of locations in the three-dimensional model based on a modification of the three-dimensional model reflecting the placement of the stent at the location indicated in the first input.

Additional embodiments and advantages will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the disclosure. The embodiments and advantages will be realized and attained by means of the elements and combinations particularly pointed out below.

DESCRIPTION OF THE EMBODIMENTS

In an exemplary embodiment, a method and system determines various information relating to blood flow in a specific patient using information retrieved from the patient. The determined information may relate to blood flow in the patient's coronary vasculature. Alternatively, the determined information may relate to blood flow in other areas of the patient's vasculature, such as carotid, peripheral, abdominal, renal, and cerebral vasculature.

The coronary vasculature includes a complex network of vessels ranging from large arteries to arterioles, capillaries, venules, veins, etc. The coronary vasculature circulates blood to and within the heart and includes an aorta2(FIG. 2) that supplies blood to a plurality of main coronary arteries4(FIG. 2) (e.g., the left anterior descending (LAD) artery, the left circumflex (LCX) artery, the right coronary (RCA) artery, etc.), which may further divide into branches of arteries or other types of vessels downstream from the aorta2and the main coronary arteries4. Thus, the exemplary method and system may determine various information relating to blood flow within the aorta, the main coronary arteries, and/or other coronary arteries or vessels downstream from the main coronary arteries. Although the aorta and coronary arteries (and the branches that extend therefrom) are discussed below, the disclosed method and system may also apply to other types of vessels.

In an exemplary embodiment, the information determined by the disclosed methods and systems may include, but is not limited to, various blood flow characteristics or parameters, such as blood flow velocity, pressure gradient, pressure (or a ratio thereof), flow rate, and fractional flow reserve (FFR) at various locations in the aorta, the main coronary arteries, and/or other coronary arteries or vessels downstream from the main coronary arteries. This information may be used to determine whether a lesion is functionally significant and/or whether to treat the lesion, and/or to predict the results of various treatment options. This information may be determined using information obtained noninvasively from the patient. As a result, the decision whether to treat a lesion may be made without the cost and risk associated with invasive procedures.

FIG. 1shows aspects of a system for providing various information relating to coronary blood flow in a specific patient, according to an embodiment. Additional details relating to various embodiments of methods and systems for determining blood flow information in a specific patient are disclosed, for example, in U.S. Patent Application Publication No. 2012/0041739 entitled “Method And System For Patient-Specific Modeling Of Blood Flow,” which is incorporated by reference in its entirety.

Patient-specific anatomical data10may be obtained, such as data regarding the geometry of the patient's heart, e.g., at least a portion of the patient's aorta, a proximal portion of the main coronary arteries (and the branches extending therefrom) connected to the aorta, and the myocardium. The patient-specific anatomical data10may be obtained noninvasively, e.g., using a noninvasive imaging method. For example, CCTA is an imaging method in which a user may operate a computer tomography (CT) scanner to view and create images of structures, e.g., the myocardium, the aorta, the main coronary arteries, and other blood vessels connected thereto. Alternatively, other noninvasive imaging methods, such as magnetic resonance imaging (MRI) or ultrasound (US), or invasive imaging methods, such as digital subtraction angiography (DSA), may be used to produce images of the structures of the patient's anatomy. The resulting imaging data (e.g., provided by CCTA, MRI, etc.) may be provided by a third-party vendor, such as a radiology lab or a cardiologist, by the patient's physician, etc. Other patient-specific anatomical data10may also be determined from the patient noninvasively, e.g., blood pressure in the patient's brachial artery (e.g., using a pressure cuff), such as the maximum (systolic) and minimum (diastolic) pressures.

A three-dimensional model12(FIGS. 2 and 3) of the patient's anatomy may be created using the patient-specific anatomical data10. In an embodiment, the portion of the patient's anatomy that is represented by the model12may include at least a portion of the aorta2and a proximal portion of the main coronary arteries4(and the branches extending or emanating therefrom) connected to the aorta2. The three-dimensional model12may also include other portions of the patient's anatomy, such as the left and/or right ventricles, calcium and/or plaque within the coronary arteries4and/or the branches, other tissue connected to and/or surrounding the coronary arteries4and/or the branches, etc.

Various physiological laws or relationships20relating to coronary blood flow may be deduced, e.g., from experimental data. Using the model12and the deduced physiological laws20, a plurality of equations30relating to coronary blood flow may be determined. For example, the equations30may be determined and solved using any numerical method, e.g., finite difference, finite volume, spectral, lattice Boltzmann, particle-based, level set, finite element methods, etc. The equations30may be solvable to determine information (e.g., pressure, pressure gradients, FFR, etc.) relating to the coronary blood flow in the patient's anatomy at various points in the anatomy represented by the model12.

In an embodiment, the model12may be prepared for analysis and boundary conditions may be determined. For example, the model12may be trimmed and discretized into a volumetric mesh, e.g., a finite element or finite volume mesh. The volumetric mesh may be used to generate the equations30.

Boundary conditions may be determined using the physiological laws20and incorporated into the equations30. The boundary conditions may provide information about the model12at its boundaries, e.g., the inflow boundaries, the outflow boundaries, the vessel wall boundaries, etc. The inflow boundaries may include the boundaries through which flow is directed into the anatomy of the three-dimensional model, such as at an end of the aorta near the aortic root. Each inflow boundary may be assigned, e.g., with a prescribed value or field for velocity, flow rate, pressure, or other characteristic, by coupling a heart model and/or a lumped parameter model to the boundary, etc. The outflow boundaries may include the boundaries through which flow is directed outward from the anatomy of the three-dimensional model, such as at an end of the aorta near the aortic arch, and the downstream ends of the main coronary arteries and the branches that extend therefrom. Each outflow boundary can be assigned, e.g., by coupling a lumped parameter or distributed (e.g., a one-dimensional wave propagation) model. The prescribed values for the inflow and/or outflow boundary conditions may be determined by noninvasively measuring physiologic characteristics of the patient, such as, but not limited to, cardiac output (the volume of blood flow from the heart), blood pressure, myocardial mass, etc. The vessel wall boundaries may include the physical boundaries of the aorta, the main coronary arteries, and/or other coronary arteries or vessels of the model12.

The equations30may be solved using a computer system40. Based on the solved equations30, the computer system40may output information50indicating one or more blood flow characteristics, such as FFR, blood pressure (or pressure gradient), blood flow, or blood velocity, determined based on the solution of the equations30. The computer system40may output images generated based on the model12and the information50or other results of the computational analysis, as described below. The information50may be determined under simulated conditions of increased coronary blood flow or hyperemia conditions, e.g., conventionally induced by intravenous administration of adenosine. For example, the boundary conditions described above may specifically model conditions of increased coronary blood flow, hyperemia conditions, and/or the effect of adenosine.

FIG. 2shows a computed FFR model100that may be output from the computer system40. The computed FFR model100may include the geometry of the anatomical structure based on the model12and may also indicate the information50output from the computer system40, such as the values of FFR at various locations along three-dimensions in the model12. FFR may be calculated as the ratio of the blood pressure at a particular location in the model12(e.g., in a coronary artery) divided by the blood pressure in the aorta, e.g., at the inflow boundary of the model12, under conditions of increased coronary blood flow or hyperemia conditions. A corresponding color, shade, pattern, or other visual indicator may be assigned to the respective FFR values throughout the computed FFR model100such that the computed FFR model100may visually indicate the variations in FFR throughout the model100without having to visually indicate the individual numerical values for each point in the model100.

A scale or key110may be provided that indicates which numerical values of FFR correspond to which colors, shades, patterns, or other visual indicators. For example, the computed FFR model100may be provided in color, and a color spectrum may be used to indicate variations in computed FFR throughout the model100. The color spectrum may include red, yellow, green, cyan, and blue, in order from lowest computed FFR (indicating functionally significant lesions) to highest computed FFR. For example, the upper limit (blue) may indicate an FFR of 1.0, and the lower limit (red) may indicate approximately 0.7 (or 0.75 or 0.8) or less, with green indicating approximately 0.85 (or other value approximately halfway between the upper and lower limits). For example, the lower limit may be determined based on a lower limit (e.g., 0.7, 0.75, or 0.8) used for determining whether the computed FFR indicates a functionally significant lesion or other feature that may require intervention. Thus, the computed FFR model100for some patients may show a majority or all of the aorta as blue or other color towards the higher end of the spectrum, and the colors may change gradually through the spectrum (e.g., towards the lower end of the spectrum (down to anywhere from red to blue)) towards the distal ends of the coronary arteries and the branches that extend therefrom. The distal ends of the coronary arteries for a particular patient may have different colors, e.g., anywhere from red to blue, depending on the local values of computed FFR determined for the respective distal ends.

For example, the computed FFR model100ofFIG. 2may show that, for this particular patient, under simulated hyperemia conditions, the computed FFR is generally uniform and approximately 1.0 in the aorta (e.g., as indicated by the color blue), and that the computed FFR gradually and continuously decreases (e.g., to values ranging from near 1.0 down to approximately 0.9, as indicated by gradually changing colors from blue to cyan or a mix of blue and cyan) as the blood flows downstream into the main coronary arteries and into the branches. However, at certain areas, such as areas112and114, there may be sharper decreases in computed FFR. For example, between the aorta and area112in one of the coronary arteries, the computed FFR model100may indicate generally constant values (e.g., approximately 1.0, as indicated by the color blue) or gradually decreasing values in computed FFR (e.g., to values ranging from near 1.0 down to approximately 0.9, as indicated by gradually changing colors from blue to cyan or a mix of blue and cyan). At area112, the computed FFR model100may indicate a drop in computed FFR to approximately 0.8 (e.g., as indicated by colors changing from blue and/or cyan, to green and/or yellow). Between the areas112and114, the computed FFR model100may indicate generally constant values (e.g., approximately 0.8, as indicated by the colors green and/or yellow) or gradually decreasing values in computed FFR (e.g., to values slightly less than 0.8, as indicated by colors that are more yellow than green). At area114, the computed FFR model100may indicate a drop in computed FFR to approximately 0.7 or below (e.g., as indicated by colors changing from green and/or yellow, to red). Downstream of the area114and to the distal end of the coronary artery, the computed FFR model100may indicate that the computed FFR is approximately 0.7 or below (e.g., as indicated by the color red).

Based on the computed FFR model100, a user may determine that the computed FFR has dropped below the lower limit used for determining the presence of a functionally significant lesion or other feature that may require intervention (e.g., based on the location(s) of areas colored red in the computed FFR model100or otherwise indicating a value of computed FFR that is below the lower limit), and the user may also be able to locate the functionally significant lesion(s). The user may locate the functionally significant lesion(s) based on the geometry of the artery or branch (e.g., using the computed FFR model100). For example, the functionally significant lesion(s) may be located by finding a narrowing or stenosis located near (e.g., upstream from) the location(s) of the computed FFR model100indicating the local minimum FFR value.

FIG. 3shows a computed pressure gradient model200that may be output from the computer system40. The computed pressure gradient model200may include the geometry of the anatomical structure based on the model12and may also indicate the information50output from the computer system40, such as the values of blood pressure gradient at various locations along three-dimensions in the model12. The computed pressure gradient model200may show the local blood pressure gradient (e.g., in millimeters of mercury (mmHg) per centimeter) throughout the model12under simulated hyperemia conditions or other conditions. A corresponding color, shade, pattern, or other visual indicator may be assigned to the respective pressures gradients such that the model200may visually indicate variations in pressure gradient throughout the model200without having to visually indicate the individual pressure gradient numerical values for each point in the model200.

A scale or key210may be provided that indicates which numerical values of pressure gradient correspond to which colors, shades, patterns, or other visual indicators. For example, the computed pressure gradient model200may be provided in color, and a color spectrum may be used to indicate variations in pressure throughout the model200. The color spectrum may include red, yellow, green, cyan, and blue, in order from highest pressure gradient, which may indicate functionally significant lesions, to lowest pressure gradient. For example, the upper limit (red) may indicate approximately 20 mmHg/cm or more, and the lower limit (blue) may indicate approximately 0 mmHg/cm or less, with green indicating approximately 10 mmHg/cm (or other value approximately halfway between the upper and lower limits). Thus, the computed pressure gradient model200for some patients may show a majority or all of the aorta as blue and/or cyan, or other color towards the lower end of the spectrum, and the colors may change gradually through the spectrum (e.g., towards the higher end of the spectrum (up to red)) at areas having higher pressure gradients.

For example, the computed pressure gradient model200ofFIG. 3may show that, for this particular patient, under simulated hyperemia conditions, the pressure gradient may be generally uniform and approximately zero mmHg/cm (e.g., as indicated by the colors blue and/or cyan) in the aorta and in most of the main coronary arteries and the branches. The computed pressure gradient model200may indicate a gradual increase in pressure gradient such that some areas212in the main coronary arteries and the branches indicate values of approximately 5 mmHg/cm to approximately 10 mmHg/cm (e.g., as indicated by the colors cyan and/or green), some areas214in the main coronary arteries and the branches indicate values of approximately 10 mmHg/cm to approximately 15 mmHg/cm (e.g., as indicated by the colors green and/or yellow), and some areas216in the main coronary arteries and the branches indicate values of greater than approximately 15 mmHg/cm (e.g., as indicated by the colors yellow and/or red).

Based on the computed pressure gradient model200, a user may determine that the computed pressure gradient has increased above a certain level (e.g., approximately 20 mmHg/cm), which may indicate the presence of a functionally significant lesion or other feature that may require intervention, and the user may also be able to locate the functionally significant lesion(s). The user may locate the functionally significant lesion(s) based on the geometry of the artery or branch (e.g., using the computed pressure gradient model200). For example, the functionally significant lesion(s) may be located by finding a narrowing or stenosis located near the location(s) of the computed pressure gradient model200indicating a value of approximately 20 mmHg/cm or higher.

The computer FFR model100, the computed blood pressure gradient model200, or other model may also include other information, such as geometry information (e.g., numerical values for vessel inner diameter, thickness, etc.), throughout the model100or200. The information relating to a particular location on the model may be displayed to the user upon selection of the location of the model as described below.

The computer system40may allow the user to select whether to output the computed FFR model100, the computed blood pressure gradient model200, or other model, and/or to specify other color mappings or rendering styles (e.g., x-ray rendering).

Referring back toFIG. 1, the computer system40may include one or more non-transitory computer-readable storage devices that store instructions that, when executed by a processor, computer system, etc., may perform any of the actions described herein for providing various information relating to blood flow in the patient. The computer system40may include a desktop or portable computer, a workstation, a server, a personal digital assistant, or any other computer system. The computer system40may include a processor, a read-only memory (ROM), a random access memory (RAM), an input/output (I/O) adapter for connecting peripheral devices (e.g., an input device, output device, storage device, etc.), a user interface adapter for connecting input devices such as a keyboard, a mouse, a touch screen, a voice input, and/or other devices, a communications adapter for connecting the computer system40to a network, a display adapter for connecting the computer system40to a display, etc. For example, the display may be used to display the model12and/or any images generated by solving the equations30(e.g., the computed FFR model100, the computed blood pressure gradient model200, and/or the other models described below).

The patient-specific anatomical data10may be transferred over a secure communication line (e.g., via a wireless or wired network) to the computer system40, which may create the model12and solve the equations30. For example, in an embodiment, the data10may be transferred from the third-party vendor that obtains the patient-specific anatomical data10to the computer system40operated by the patient's physician or other user.

In an embodiment, the computer system40may output the information50indicating one or more blood flow characteristics, the computed FFR model100, the computed blood pressure gradient model200, and/or other output from the computer system40based on the solution of the equations30to a tablet computer70(or other mobile or handheld computing device), such as Apple Inc.'s iPad®, over a secure communication line (e.g., via a wireless or wired network, using a web-based service, etc.). The tablet computer70may be operated by the patient's physician or other user, such as the patient. The tablet computer70may include a touchscreen. Various screenshots of the touchscreen are shown inFIGS. 2-6and described below. The touchscreen may be configured to receive input from the user based on contact by at least one of the user's digits (e.g., at least one of the user's fingers or thumbs) on a surface of the touchscreen as described below. The following description relates to embodiments in which the touchscreen is configured to receive input from contact by the user's finger(s) on the surface of the touchscreen. However, it is understood that the touchscreen may be configured to receive input from the user based on contact or sensed proximity to the touchscreen by the user's finger(s), the user's thumb(s), a stylus, another pointing object or instrument, or a combination thereof.

Thus, in an embodiment, the computer system40may perform more complicated operations, such as solving the equations30, while the tablet computer70may be a portable system for displaying the results of the solution of the equations30by the computer system40and for performing less complicated computations. The tablet computer70may allow the patient's physician, the patient, or other user to access information from the model12,100, or200, and manipulate the model12,100, or200as described below. The tablet computer70may also be configured to allow the user to select treatment options using the tablet computer70. The tablet computer70may determine or predict the blood flow characteristic(s) (e.g., FFR, blood pressure (or pressure gradient), etc.) in the patient's anatomical structure based on the selected treatment options as described below.

For example, as shown inFIGS. 2-4, the tablet computer70may provide two mode selection buttons310and320that allow the user to switch between two modes. Touching the first button310allows the user to select the first operating mode (e.g., an inspection mode), and touching the second button320allows the user to select the second operating mode (e.g., a percutaneous coronary intervention (PCI) mode).

FIGS. 2 and 3are images illustrating screen shots of the tablet computer70operating in the first operating mode. In the first operating mode, the tablet computer70may display information indicating one or more blood flow characteristics of the patient in the patient's current condition, e.g., the computed FFR model100(FIG. 2), the computed pressure gradient model200(FIG. 3), or other model providing the information50output from the computer system40. Inputs received from the user using the tablet computer70in the first operating mode may allow the user to interact with and manipulate the displayed information regarding the patient's current condition.

The tablet computer70may be configured to determine when the user's finger(s) contact the surface of the touchscreen at a location corresponding to a location on the displayed model100or200(and a corresponding location in the patient's anatomical structure). Based on this input, the tablet computer70may determine the numerical value of a blood flow characteristic (e.g., FFR, blood pressure (or pressure gradient), and/or other blood flow characteristic selected by the user) at the indicated location on the displayed model100or200, and may display the determined numerical value. The displayed numerical value may be dynamically updated as the user drags the finger(s) along the surface of the touchscreen and along the displayed model100or200. Thus, the user may touch any point on the model12,100, or200to determine the numerical value of any of the blood flow characteristics described above, e.g., FFR, blood pressure (or pressure gradient), and/or other blood flow characteristic, at that point. Additional information relating to the indicated point on the model12,100, or200may also be displayed to the user, such as geometry information (e.g., a numerical value of the vessel inner diameter, etc.).

For example, the tablet computer70may be configured to determine when the user's finger(s) contact the surface of the touchscreen for a predetermined time (e.g., a touch and hold) at a location corresponding to a location on the displayed model100or200. Based on this input, the tablet computer70may create a tag or pin330that points to the indicated location within the displayed model100or200. The user can then drag or move the pin330anywhere within the displayed model100or200to determine the numerical value of a blood flow characteristic at the indicated location on the displayed model100or200to which the pin330has been dragged. The numerical value may be dynamically updated as the pin330is dragged. The tablet computer70may display the determined numerical value within or near the pin330. For example, inFIGS. 2 and 3, the pin330points to a location in one of the coronary arteries illustrated in the model100where the FFR value is 0.58. The pin330may also indicate other information regarding the indicated location, such as a dimension (e.g., diameter) of the vessel at the indicated location. The tablet computer70may allow the user to create more than one pin330to drag separately around the model100or200, and remove the pin(s)330, as desired.

When the user's finger(s) contact the surface of the touchscreen (e.g., for less than the amount of time associated with creating the pin330) at a location corresponding to a location on the displayed model100or200, then the tablet computer70may determine that the user has selected a particular coronary artery (and/or the branches connected thereto) and may fade (e.g., dim or decrease the brightness of) the other coronary arteries and branches.

Alternatively, or in addition, the selected location may become a new focal point of view for the displayed model100or200, and/or a new local origin for transformations, such as rotation and zoom. This allows the user to focus in on a potential stenosis, and to rotate around or zoom to (or away from) any user-defined point.

The tablet computer70may also be configured to determine when the user's finger(s) swipe or drag on the surface of the touchscreen (e.g., at a location away from the pin330). Based on this input, the tablet computer70may rotate the displayed model100or200. The amount and direction of rotation may depend on the distance that the finger(s) travel in contacting the surface of the touchscreen during the swipe and the direction of the swipe along the surface of the touchscreen.

The tablet computer70may also be configured to determine when the user's fingers pinch the surface of the touchscreen. If the user's fingers move closer together, the tablet computer70may zoom out from the displayed model100or200. If the user's fingers move away from each other, the tablet computer70may zoom in on the displayed model100or200. The amount of the zoom may depend on the distance that the finger(s) travel in the pinch along the surface of the touchscreen.

As the user manipulates the view of the displayed model100or200(e.g., by rotating, zooming in or away, changing the focal point, etc.), the tube angulation or other information for characterizing the direction from which the anatomical structure is being viewed may be displayed to the user and dynamically updated. For example, the information may be provided in the form of left anterior oblique (LAO), right anterior oblique (RAO), caudal (CAUD), and/or cranial (CRAN) angles, e.g., LAO 20° and CRAN 0°, as known in the art.

FIGS. 4-6are images illustrating screen shots of the tablet computer70operating in the second operating mode (e.g., the PCI mode) selected by the user by touching the second button320. Inputs received from the user using the tablet computer70in the second operating mode allow the user to plan treatment options using the displayed model400, which may be created based on the model12(e.g., a model reflecting the geometry of the patient's anatomical structure without additional information indicating blood flow characteristic(s)), the computed FFR model100(FIG. 2), the computed pressure gradient model200(FIG. 3), or other model providing information50indicating a blood flow characteristic of the patient in the patient's current condition. The tablet computer70may display predicted information regarding the blood flow characteristic(s) (e.g., FFR, blood pressure (or pressure gradient), etc.) based on the selected the treatment option.

FIG. 4shows a screen shot of the tablet computer70operating in the second operating mode to allow the user to select a treatment option using the model400. In the embodiment shown inFIG. 4, the model400is created based on the computed FFR model100. Alternatively, the model400may be created based on the model12, the computed pressure gradient model200, and/or other model. The tablet computer70may be configured to determine when the user's finger(s) contact the surface of the touchscreen (e.g., for a predetermined time (e.g., a touch and hold)) at a location corresponding to a location on the displayed model400(and a corresponding location in the patient's anatomical structure). Based on this input, the tablet computer70may display a stent410for planned insertion into the patient's anatomical structure (e.g., in a coronary artery). The tablet computer70may allow the user to place more than one stent410on the model400, as shown inFIG. 5, and remove the stent(s)410, as desired.

When initially placed on the model400, the stent410may have a predetermined size or dimension, or other characteristics (e.g., diameter, length, material, wire thickness, wire configuration, etc.). The stent410may be initially placed so that the stent410is centered longitudinally with respect to the location selected by the user.

The user may then provide additional inputs to define and/or adjust the stent410. For example, the tablet computer70may be configured to determine when the user's finger(s) swipe or drag on the surface of the touchscreen. Based on this input, the tablet computer70may move the stent410along the model400. For example, the stent410may move parallel to the centerline(s) of the coronary artery or arteries (or branches connected thereto). Also, the shape of the stent410may conform to bends and curves in the centerline(s), as shown inFIGS. 4-6, as the stent410is dragged or moved along the centerline(s). The amount and direction (e.g., upstream or downstream along the centerline(s)) of movement of the stent410may depend on the distance that the finger(s) travel in contacting the surface of the touchscreen during the swipe and the direction of the swipe along the surface of the touchscreen.

The tablet computer70may also be configured to determine when the user's fingers pinch the surface of the touchscreen. If the user's fingers move closer together, the tablet computer70may shorten the stent410(e.g., in the longitudinal direction and/or the direction of the centerline(s)). If the user's fingers move away from each other, the tablet computer70may lengthen the stent410(e.g., in the longitudinal direction and/or the direction of the centerline(s)). The amount of the change in length may depend on the distance that the finger(s) travel along the surface of the touchscreen to form the pinch. Also, the change in length may be continuous or may be provided in increments (e.g., approximately 4 millimeter increments or other increment). For example, if the stent410has a sequential ring configuration (e.g., a series of sequential rings that are joined together to form a tubular structure), then the change in length may be provided in increments that are generally equivalent to a length of one ring, and the touchscreen may show the ring(s) being added or removed from the stent410to shorten or lengthen the stent410.

Other features may be provided that allow the user to adjust and manipulate the stent410.FIG. 5shows a screen shot of the tablet computer70operating in the second operating mode to allow the user to plan a treatment option associated with the placement of the stent410using the model400, according to another embodiment.

When displaying the stent410for planned insertion into the patient's anatomical structure (e.g., in a coronary artery), the tablet computer70may create one or more handles, such as a first handle420, a second handle430, and/or a third handle440. The first handle420may be located at or near the center of the stent410along the longitudinal direction. The user may drag or move the stent410along the model400by pressing the first handle420and dragging the first handle420to a desired location on the model400. Movement of the first handle420results in movement of the stent410. As the user drags the first handle420along the model400, the stent410may also move parallel to the centerline(s) of the coronary artery or arteries (or branches connected thereto) until the user removes the finger(s) from the first handle420. Also, the shape of the stent410may conform to bends and curves in the centerline(s) as the stent410is dragged or moved along the centerline(s) with the first handle420.

The second and third handles430,440may be located at or near the proximal and distal ends of the stent410, respectively. The user may adjust the length of the stent410by pressing the second and/or the third handles430,440and dragging the respective second and/or third handles430,440along the model400, thereby adjusting the locations of the respective proximal and distal ends of the stent410. Movement of the second and/or third handles430,440results in lengthening/shortening of the stent410. For example, when the user drags the second handle430along the model400in a proximal direction away from the third handle440, the stent410may lengthen and extend along the proximal direction. Similarly, when the user drags the third handle440along the model400in a distal direction away from the second handle430, the stent410may lengthen and extend along the distal direction. The new portion of the stent410that is added due to the lengthening may be formed parallel to the centerline(s) of the coronary artery or arteries (or branches connected thereto) and may conform to bends and curves in the centerline(s). Alternatively, the stent410may shorten when the user drags the second handle430along the model400in a distal direction toward the third handle440or when the user drags the third handle440along the model400in a proximal direction toward the second handle430. As the length of the stent410is altered, the placement of the first handle420may be automatically adjusted so that the first handle420stays at or near the center of the stent410. As a result, the handles420,430,440are user-friendly and allow the user to manipulate and adjust the stent410as desired.

Various characteristics of the stent410may be displayed on the touchscreen. For example, the numerical values of the length, the proximal diameter, and/or the distal diameter of the stent410may be displayed on the touchscreen, e.g., in a stent legend. The numerical values may be dynamically updated as the user adjusts the stent410.

Other characteristics of the stent410, e.g., the material, wire thickness, wire configuration, etc., may be selected by the user. For example, the tablet computer70may provide a selection of stent models that are available for placement into the patient and may store the characteristics of those stent models. The user may select from the stent models, and the tablet computer70may retrieve the stored characteristics corresponding to the stent model selected by the user to determine the various characteristics of the stent410, such as the dimensions of the stent410. In addition, other characteristics of the stent410may be determined based on the stent model selected, such as the dimensions of the incremental changes in length (e.g., the size of the rings in a ring configuration) described above and/or the flexibility of the stent410(e.g., the ability to conform to the bends and curves in the centerlines of the coronary arteries and branches).

Alternatively, the various characteristics of the stent410and/or the stent model may be determined automatically and recommended by the tablet computer70based on various factors, such as the location of any FFR values that are less than 0.75 and the dimensions of the vessels at those locations, locations and dimensions of significant narrowing of the vessels, etc.

The tablet computer70may also provide other treatment options for selection by the user, such as other types of surgery on the modeled anatomy that may result in a change in the geometry of the modeled anatomy. For example, the tablet computer70may be used to plan a coronary artery bypass grafting procedure. Coronary artery bypass grafting may involve creating new lumens or passageways in the model400. After selecting this type of treatment option, the tablet computer70may be configured to determine when the user's finger(s) contact the surface of the touchscreen (e.g., for a predetermined time (e.g., a touch and hold)) at a location corresponding to a location on the displayed model400. Based on this first input, the tablet computer70may display a bypass segment (not shown) for planned connection to the patient's anatomical structure (e.g., in a coronary artery), which has one end that is connected to the model400at the location indicated by the first input. The tablet computer70may then prompt the user to provide a second input identifying a second location for connecting the opposite end of the bypass segment to the patient's anatomical structure. Alternatively, the tablet computer70may recommend where to connect the bypass segment at one or both ends of the bypass segment. The tablet computer70may allow the user to place more than one bypass segment in the model, and remove the bypass segment(s), as desired. The tablet computer70may also allow the user to provide inputs (e.g., similar to the inputs described above, such as swiping and pinching) to change the location or dimension (e.g., diameter, length, etc.) of the bypass segment.

Once the treatment option(s) have been selected by the user, the user may touch a calculate button340, as shown inFIG. 4. When the user selects the calculate button340, the tablet computer70recalculates the blood flow characteristic(s).

For example, referring back toFIG. 1, after the computer system40solves the equations30as described above, the computer system40may create and transmit to the tablet computer70a reduced-order (e.g., zero-dimensional or one-dimensional) model60for modeling various treatment options, in addition to (or instead of) the information50indicating the blood flow characteristics in the patient's current condition, as disclosed, for example, in U.S. Patent Application Publication No. 2012/0041739 entitled “Method And System For Patient-Specific Modeling Of Blood Flow.” For example, the reduced-order model60may be a lumped parameter model or other simplified model of the patient's anatomy that may be used to determine information about the coronary blood flow in the patient without having to solve the more complex system of equations30described above. The reduced-order model60may be created using information extracted from the computed models100and200(e.g., the blood pressure, flow, or velocity information determined by solving the equations30described above).

After the user touches the calculate button340, the tablet computer70may adjust the reduced-order model60based on the treatment option selected by the user, and may solve a simplified set of equations based on the reduced-order model60to output information indicating one or more predicted blood flow characteristics (e.g., FFR, blood pressure (or pressure gradient), etc.) of the patient. The information may then be mapped or extrapolated to the three-dimensional model12of the patient's anatomical structure to display the effects of the selected treatment option on the coronary blood flow in the patient's anatomy, e.g., in a post-intervention model500, as shown inFIG. 6.

Since the reduced-order model60may be solved with a simplified set of equations (compared to the equations30), the reduced-order model60permits relatively rapid computation (e.g., compared to a full three-dimensional model) using the tablet computer70and may be used to solve for flow rate and pressure that may closely approximate the results of a full three-dimensional computational solution. Thus, the reduced-order model60allows for relatively rapid iterations to model various different treatment options.

Alternatively, instead of creating the reduced-order model60and transmitting the reduced-order model60to the tablet computer70, the inputs provided by the user to select the treatment option may be transmitted to the computer system40via the tablet computer70(e.g., via a wired or wireless connection). After the user touches the calculate button340, the computer system40may recalculate the information indicating the blood flow characteristic(s), e.g., by re-solving the equations30using the inputs provided by the user to select the treatment option. The computer system40may then transmit to the tablet computer70the information indicating the blood flow characteristic(s) based on this solution to the equations30, and may also output to the tablet computer70images generated based on the model12and the determined information, such as the post-intervention model500shown inFIG. 6.

FIG. 6shows a screen shot of the tablet computer70operating in the second operating mode after determining the information indicating the blood flow characteristic(s) of the patient based on the selected treatment option, according to an embodiment. Specifically, the screen shot shows a split screen provided by touchscreen, and the split screen may divide the screen into two or more portions. In the embodiment shown inFIG. 6, two portions may be provided. The first portion of the split screen (the left side portion shown inFIG. 6) may show the pre-intervention model400(FIG. 4) with the treatment option selected by the user (placement of the stent410, as described above in connection withFIG. 4).

The second portion of the split screen (the right side portion shown inFIG. 6) may show the post-intervention model500that reflects the information indicating the blood flow characteristic(s) of the patient based on selected treatment option. The post-intervention model500may show any change in geometry of the anatomical structure due to the selected treatment option. For example, in the embodiment shown inFIG. 6, the post-intervention model500shows a widening510of the lumen where the simulated stent410is placed. The post-intervention model500may also display the start and end points of the stent410.

In the embodiment shown inFIG. 6, the pre-intervention and post-intervention models400,500indicate computed FFR. The split screen allows the user to view and compare information relating to the untreated patient (e.g., without the stent(s)), such as the model400, side-by-side with information relating to the simulated treatment for the patient, such as the model500. For example, the same color, shade, pattern, or other visual indicators as the model400may be assigned to the respective FFR values for the model500. Thus, the model500may also visually indicate the variations in FFR throughout the model500without having to specify the individual values for each point in the model500. The model500shown inFIG. 6shows that, for this particular patient, under the treatment plan selected by the user, FFR is generally uniform and approximately 1.0 in the aorta (e.g., as indicated by the color blue), and that FFR gradually and continuously decreases (e.g., to values ranging from 1.0 down to approximately 0.9, as indicated by gradually changing colors from blue to cyan or a mix of blue and cyan) in the main coronary arteries and the branches. In this embodiment, the post-interventional model500does not include the areas112and114of sharper decreases in FFR that are shown in the pre-interventional model400. Thus, the split screen provides a comparison of the pre-interventional model400of the untreated patient (showing the patent's current condition) and the post-interventional model500for the proposed treatment to help the physician or other user to assess the results of various treatment options.

Either portion of the split screen may be configured to receive inputs from the user and may respond to the inputs as described above in connection with the first operating mode. For example, the user may touch any location on the model(s)400and/or500to determine the numerical value of any of the blood flow characteristic(s) and/or geometry information at that location, e.g., by creating one or more pins330for moving around the model(s)400and/or500. In an embodiment, when the user touches a location (or creates the pin330) on one of the models400or500to determine the numerical value of the blood flow characteristic(s) and/or geometry information at the indicated location, the numerical value of the blood flow characteristic(s) and/or geometry information at the same location in the other model400or500may also be displayed for comparison. For example, another pin330may be automatically created at the same location in the other model400or500. As a result, the split screen may provide mirrored pins330in the two displayed models such that movement of one pin330in one of the models due to user input is automatically mirrored by the pin330in the other model and the numerical values of the blood flow characteristic(s) and/or geometry information at the respective locations may be compared and updated dynamically as the pins330move.

Also, the user may adjust the rotation, zoom, and/or focal point for the model(s)400and/or500. In an embodiment, when the user adjusts the rotation, zoom, and/or focal point for one of the models400or500, the rotation, zoom, and/or focal point for the other model400or500is adjusted similarly.

The first portion of the split screen (showing the pre-intervention model400) may be configured to receive inputs from the user and may respond to the inputs as described above in connection with the second operating mode. For example, the user may select or adjust the treatment option using the pre-intervention model400. After making the desired changes, the user may touch the calculate button340, which may cause the tablet computer70to modify the reduced-order model60based on the new treatment option selected by the user. After solving the equations associated with the modified reduced-order model60, the tablet computer70may output a modified post-intervention model500that reflects the new treatment option selected by the user. Alternatively, the tablet computer70may transmit the new treatment option to the computer system40, which will re-solve the equations30based on the new selected treatment option, and send the modified post-intervention model500to the tablet computer70for displaying to the user.

Alternatively, the split screen may provide two portions for comparing the results of different treatment options. In such an embodiment, each portion of the split screen may be configured to receive inputs associated with selecting treatment options using the pre-intervention model400as described above and may be able to display different post-intervention models500based on the different treatment options selected.

Accordingly, the split screen allows the user to repeatedly select new treatment options and use the tablet computer70to predict and compare the effects of various treatment options to each other and/or to information relating to the untreated patient. The reduced-order model60may allow the user to analyze and compare different treatment options more easily and quickly without having to solve the equations30each time a different treatment option is selected.

The system may be used to predict a potential benefit of percutaneous coronary interventions on coronary artery blood flow in order to select the optimal interventional strategy, and/or to predict a potential benefit of coronary artery bypass grafting on coronary artery blood flow in order to select the optimal surgical strategy.

The systems and methods disclosed herein may be incorporated into a portable software tool accessed by physicians and other users to provide patient-specific blood flow information and to plan treatment options. In addition, physicians and other users may use the portable software tool to predict the effect of medical, interventional, and/or surgical treatments on coronary artery blood flow. The portable software tool may be used to prevent, diagnose, manage, and/or treat disease in other portions of the cardiovascular system including arteries of the neck (e.g., carotid arteries), arteries in the head (e.g., cerebral arteries), arteries in the thorax, arteries in the abdomen (e.g., the abdominal aorta and its branches), arteries in the arms, or arteries in the legs (e.g., the femoral and popliteal arteries). The portable software tool may be interactive to enable physicians and other users to develop optimal personalized therapies for patients.

The computer system40for solving the equations30governing blood flow may be provided as part of a web-based service or other service, e.g., a service provided by an entity that is separate from the physician. The service provider may, for example, operate the web-based service and may provide a web portal or other web-based application (e.g., run on a server or other computer system operated by the service provider) that is accessible to physicians or other users via a network or other methods of communicating data between computer systems. For example, the patient-specific anatomical data10obtained noninvasively from the patient may be provided to the service provider, and the service provider may use the data to produce the three-dimensional model12or other models/meshes and/or any simulations or other results determined by solving the equations30described above in connection withFIG. 1, such as the reduced-order model60, the computed FFR model100, and/or the computed blood pressure gradient model200. Then, the web-based service may transmit the models60,100, and/or200to the physician's tablet computer70(or other portable device). The physician may use the tablet computer70to interact with the models100or200, and to provide inputs, e.g., to select possible treatment options and determine blood flow information based on the selected possible treatment options.

It will be apparent to those skilled in the art that various modifications and variations can be made in the disclosed systems and processes without departing from the scope of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.