bluuebunny/crossref_metadata_2025_split huggingface dataset:
Progression of maxillofacial squamous cell carcinoma evaluated using computer graphics with spiral computed tomography
Authors: Cavalcanti M G , Ruprecht A , Quets J 
Published: October 2024

Abstract
This report describes the appearance of maxillofacial squamous cell carcinoma in multiplanar (MPR) and three-dimensional (3D) images reconstructed from spiral CT using computer graphics and the importance of the computer software tools in permitting better visualization of the lesion. Two oral and maxillofacial radiologists and one neuroradiologist analysed the images. The usefulness of interactive reconstruction in the diagnosis, surgical planning and treatment evaluation, especially in the localization of the extent of these maxillofacial tumors, was demonstrated. Spiral CT-based computer graphics for displaying MPR and 3D images are an important adjunct in the evaluation of squamous cell carcinoma.
Effects of collimator size of a dental X-ray unit on image contrast
Authors: Falk A , Lindhe J E , Rohlin M , Nilsson M 
Published: October 2024

OBJECTIVES
To examine the effect of collimator size on image contrast in dental radiography.

METHODS
Two conventional collimators, one circular (53 mm in diameter) and one rectangular (35x45 mm2), were compared with a small rectangular collimator (26x39 mm2). Low-contrast and high-contrast resolution was assessed with the aid of contrast-detail and line-pair phantoms.

RESULTS
Shallower holes were observed with the small rectangular collimator. Two-thirds of 17 observers assessing high-contrast resolution considered the small collimator to result in a clearer image than the conventional collimators. The same effect was demonstrated with the line-pair phantom and by microdensitometry. With the small collimator the energy imparted is estimated to be reduced by 54 and 36% compared with the conventional circular and rectangular collimators respectively.

CONCLUSIONS
Decrease of the collimator size to fit the film size used for children will result in improved low-contrast and, under some conditions, improved high-contrast resolution. This improvement might have implications for caries diagnosis and monitoring.
Fractal dimension calculated from two types of region of interest
Authors: Lee K I , Choi S C , Park T W , You D S 
Published: October 2024

OBJECTIVES
To compare the effect of using two region of interest (ROI) types on calculating the fractal dimensions of trabecular bone during simulated osteoporosis.

METHODS
Ten 5 mm thick cross-sections from the long bone of a cow were progressively decalcified in 0.1 N Hcl for 5, 10, 20, 30, 60 and 90 min intervals, and radiographed using 0 degrees projection angle in a specially designed device. Two types of ROI (the ruggedness of the boundary and bone profiles) were placed on each digital image. Fractal dimensions and variance in mean pixel intensity were computed from each ROI using the caliper method in ImageFractal (National Institutes of Health, Washington, DC, USA). Correlation analysis quantified the relationship between changes in variance and fractal dimensions of the two types of ROI.

RESULTS
A Strong correlation (r=0.90 approximately 0.98, P&lt;/=0.0026) was found between variance in mean pixel intensity and decreasing fractal dimensions calculated from bone profiles. There was no consistency in the ruggedness of the boundary and increasing decalcification.

CONCLUSIONS
The fractal dimensions used to characterize the ruggedness of a boundary of trabecular bone in a two-dimensional ROI are inadequate for the detection of osteoporosis, but those calculated from bone profiles may be a sensitive descriptor of trabecular bone structure.
Mandibular osteoradionecrosis: a comparison of computed tomography with panoramic radiography
Authors: Store G , Larheim T A 
Published: October 2024

OBJECTIVES
To compare the value of computed tomography (CT) with panoramic radiography in the diagnosis and presurgical evaluation of mandibular osteoradionecrosis (ORN).

METHODS
Retrospective study comparing the diagnostic information from CT and panoramic radiography of 33 patients with clinical symptoms of ORN. In six patients the imaging was compared macroscopically with the resected mandible.

RESULTS
Both panoramic radiography and CT revealed ORN in 31 cases. In 22 the anterior-posterior extent of the lesions could be estimated with equal reliability. In six patients the lesion appeared larger on CT and in three on panoramic radiography. Mono- or bicortical destruction, central necrosis and sequestration were better visualized by CT. Comparison between the imaging findings and the surgical resection showed that CT depicted the topography of the specimen more accurately.

CONCLUSIONS
CT is superior to panoramic radiography in visualizing the features of mandibular ORN and the anterior-posterior extent of the lesion.
A method for correcting for errors produced by variable magnification in three-dimensional tuned-aperture computed tomography
Authors: Webber R L , Bettermann W 
Published: October 2024

OBJECTIVES
To develop and test a method for correcting tomosynthetic misregistration caused by variation in projective magnification.

METHODS
A tooth from a monkey was radiographed from various angles and distances using a solid-state sensor to which a plastic spacer with a wire frame was attached. The position of the tooth was fixed relative to both the frame and the sensor. Information derived from the frame's shadow was used to produce a series of tomosynthetic slices using tuned-aperture computed tomography (TACT(R)). One series was corrected for magnification errors and the other was not. Corresponding slices from each series were compared.

RESULTS
The corrected slice exhibited much less artifactual blur than its uncorrected counterpart. Linear traces through corresponding portions of these slice images demonstrated discrepancies in homologous dimensions attributable to systematic variations in projective magnification.

CONCLUSIONS
Correcting for differences in projective magnification reduces both misregistration and scaling artifacts in tomosynthetically reconstructed volumes.
Reproducible X-ray projection geometry in edentulous patients
Authors: Handschel J , Kleinheinz J , Kelker M , Reuter I , Joos U 
Published: October 2024

OBJECTIVE
To evaluate a novel fixation system for reproducible radiography in edentulous patients.

METHODS
A conventional extra-oral fixation system was modified with a filmholder and adjustable scales. For measuring reproducibility and angulation errors two rods and two balls were fixed on the alveolar crests of the maxilla and the mandible and angular variations were measured. One hundred radiographs of a conventional phantom were taken by one of the authors and by ten dental students. The angular disparity was calculated and intra- and interoperator precision determined.

RESULTS
The average time taken to assemble the fixation system was 4 min. The 95% confidence interval for precision of the single operator was less than 2.5 degrees in both the maxilla and mandible. The 95% confidence interval for precision of the ten students was less than 2.2 degrees for the maxilla and 2.7 degrees for the mandible. There was no significant difference (P&gt;0.05) in interoperator precision.

CONCLUSION
The novel extra-oral fixation system appears to be a potential means of obtaining reproducible radiographs of edentulous patients.
Cyclopia and exadactyly: CT and MRI findings.
Authors: Karantanas A H , Papanikolaou N , Danos A , Antonakopoulos G 
Published: October 2024

Abstract
Cyclopia is a congenital abnormality consisting of fused orbits and a single eye and is the most extreme form of alobar holoprosencephaly. The present case describes the CT and MRI findings in the skull of a 33-week-old cadaver with alobar holoprosencephaly and exadactyly.
An electronic survey of opinions on the compatibility of current X-ray generators with intra-oral digital X-ray systems
Authors: Hayakawa Y , Kuroyanagi K , Chen S K , Farman A G , Welander U 
Published: October 2024

OBJECTIVES
To assess opinions on the compatibility of current X-ray generators with intra-oral digital X-ray systems.

METHODS
A questionnaire was posted in both English and in Japanese on oral and maxillofacial radiology electronic bulletin boards. The questionnaire was also mailed to selected researchers and manufacturers in oral and maxillofacial radiology. The replies were evaluated to determine opinion on the current and future status of digital intra-oral imaging with special reference to their compatibility with current X-ray generators.

RESULTS
Seventy-one replies were received from 19 countries: 39% from Japan and Korea, 27% from North America, 25% from Europe and 8% from the rest of the world. Eighty per cent of respondents were from academia, 15% from industry and the remainder largely in private practice. Respondents' experience was equally divided between solid state, mainly charge-coupled devices (CCDs) and photostimulable phosphor (IP) technologies. Sixty-eight per cent considered that current X-ray generators are compatible with intra-oral digital systems and many believed this was due to their gray scale flexibility. Twenty-eight per cent believed that existing X-ray generators are inconsistent with low exposure times. Many of the replies suggested that in future pixel size would decrease and bit depth and receptor sensitivity increase.

CONCLUSIONS
Most respondents are happy to use existing X-ray generators with digital X-ray systems. However, they also believe that increased sensitivity of receptors could lead to more stringent designs of X-ray generators to ensure more reliable outputs in the low exposure range.
Interrelationship between cross-sectional and sagittal imaging in computer-assisted dental implant tomography
Authors: Thunthy K H 
Published: October 2024

OBJECTIVE
To determine what changes may occur in computer-assisted dental tomography to cross-sectional and sagittal slices when the positions of one or both slices are adjusted.

METHODS
A human skull with a ball bearing attached to the mandibular first molar was positioned off-centre in a CommCAT (Imaging Sciences International, Hatfield, PA, USA) tomographic machine. An occlusal projection of the mandibular dental arch was scanned into the computer. Correction measurements obtained from scout cross-sectional and sagittal slices were used to 'customize' cross-sectional and sagittal slices simultaneously and also individually.

RESULTS
The resulting changes in position and blur of the ball bearing were analysed. When simultaneously and correctly customized, the resultant slices were at the correct locations with a sharp image of the marker. When the sagittal slice only was adjusted, the blur of the marker changed, but its position remained unchanged; at the same time, the blur of the marker in the cross-sectional slice remained unchanged, but its position changed. When the cross-sectional slice only was adjusted, the blur changed, but its position remained unchanged; at the same time, the blur of the marker in the sagittal slice remained unchanged, but its position changed.

CONCLUSIONS
It is important for dentists evaluating tomograms for implant placement to be aware that with the CommCAT tomographic machine an interrelationship exists between cross-sectional and sagittal slices and that adjustment in one type of slice produces changes in either the blur or position of the marker in the adjusted and unadjusted slices.
Subjective image quality of solid-state and photostimulable phosphor systems for digital intra-oral radiography
Authors: Borg E , Attaelmanan A , Gröndahl H G 
Published: October 2024

OBJECTIVES
To compare subjectively the image quality of intra-oral radiographs from six digital systems.

METHODS
Two generations of two different solid-state detectors; Visualix-1 and -2 (Gendex Dental Systems, Milan, Italy), Computed Dental Radiography (CDR) and CDR Active Pixel Sensor (APS) (Schick Technologies Inc., Long Island City, NY, USA), and two photostimulable phosphor (PSP) systems; Digora (Soredex, Orion Corporation, Helsinki, Finland) and DenOptix (Gendex Dental Systems, Milan, Italy) were compared. Tooth-containing specimens from different areas of dried mandibles were radiographed at exposures between 91-9400 microGy. Images were transferred to a personal computer, displayed in random order and evaluated in their original form and after applying a histogram equalisation algorithm. Eight observers graded subjective image quality using a 5-point scale.

RESULTS
Both CDR systems scored highest for image quality but within the narrowest exposure range. The Visualix images received the lowest scores. The PSP systems produced acceptable image quality at both lower and higher exposures than the solid-state systems. Enhanced images were generally considered to be inferior to the original images, except for those produced by the four solid-state systems at very low exposures.

CONCLUSIONS
(i) the PSP systems provided a clinically acceptable image quality over a wide exposure range; (ii) the CDR systems had the best image quality but over the narrowest exposure ranges; (iii) the Visualix systems had the lowest image quality; and (iv) histogram equalisation did not generally improve image quality.
A clinical evaluation of some factors affecting image quality in panoramic radiography
Authors: Kaeppler G , Axmann-Krcmar D , Reuter I , Meyle J , Gómez-Román G 
Published: October 2024

AIM
To evaluate the suitability of panoramic radiographs obtained with two different machines for clinical use.

MATERIAL AND METHODS
Three observers assessed 111 pairs of panoramic radiographs taken with the Scanora (Soredex, Orion Corp., Helsinki, Finland) programme 001, and the Orthophos Plus (Sirona, Bensheim, Germany), programme P1 respectively, for visualisation of seven anatomical structures on each side, on a 5-point scale where 1 = very good. The median values were computed and a descriptive analysis performed. Interrater and intrarater agreement were expressed as weighted kappa.

RESULTS
The median values of both Scanora and Orthophos radiographs were the same, scoring 2. The intra- and inter-observer agreement was generally poor and similar for both machines.

CONCLUSIONS
The two panoramic machines were both given good ratings for evaluation of anatomical structures. The differences were very small and suggest that both machines are suitable for clinical use.
Radiological findings in an unusual osteosarcoma in the maxilla
Authors: Cavalcanti M G , Ruprecht A , Yang J 
Published: October 2024

Abstract
An unusual case of osteosarcoma of the maxilla, which was initially diagnosed as fibrous dysplasia on the basis of the clinical CT and histopathological findings, is presented. However, panoramic and periapical radiography suggested a malignant neoplasm. After surgery, the tumor was diagnosed histopathologically as a low-grade osteosarcoma. We conclude that panoramic and periapical radiographs are important adjuncts and should be included in any investigation of the jaws where CT scanning is unable to differentiate between osteosarcoma and fibrous dysplasia.
Parotid lymph node metastasis from adenocarcinoma of the urachus
Authors: Shimoyama T , Horie N , Yamada T , Ide F 
Published: October 2024

Abstract
The parotid gland and its lymph nodes are frequent sites of metastases from head and neck cancers. However, metastasis from a distant primary below the clavicle is unusual. These originate from a variety of sites, most commonly the lung, kidney and breast. A case of a 59-year-old woman with parotid lymph node metastasis from an adenocarcinoma of the urachus, diagnosed on the basis of two discrete periparotid masses on CT and the patient's history, is presented.
A study of the association between the prognosis of carcinoma of the mandibular gingiva and the pattern of bone destruction on computed tomography
Authors: Nakayama E , Yoshiura K , Yuasa K , Kanda S , Saitoh M , Kage W , Ikebe T , Ozeki S , Shinohara M 
Published: October 2024

OBJECTIVE
To clarify whether the pattern of bone destruction seen on CT is more closely associated with the outcome of carcinoma of the mandibular gingiva than that derived from panoramic radiographs (PR).

METHOD
Axial bone window CT scans and PR of 62 patients with carcinoma of the mandibular gingiva were evaluated retrospectively by two oral radiologists for the pattern of bone destruction. Patterns were classified into the three types: erosive, invasive and mixed. The relationship between these patterns with each imaging modality and cumulative recurrence rate, cumulative metastasis rate and cumulative survival rate, calculated by the Kaplan-Meier method, were statistically analysed by the log rank test.

RESULTS
The pattern of bone destruction derived from CT was closely associated with the cumulative metastasis rate (P &lt; 0.05), the cumulative recurrence rate and the cumulative survival rate. In contrast, the pattern of bone destruction based on the PR was not associated with the cumulative metastasis rate (P = 0.43), the cumulative recurrence rate (P = 0.44), or the cumulative survival rate (P = 0.5).

CONCLUSION
The prognosis of patients with carcinoma of the mandibular gingiva is more closely related to a classification derived from the pattern of bone destruction on CT rather than PR. However, the number of subjects investigated in this study was not large enough to confirm our conclusions statistically. Further studies by other investigators are therefore needed.
Flattening of the articular eminence correlates with progressive internal derangement of the temporomandibular joint
Authors: Kurita H , Ohtsuka A , Kobayashi H , Kurashina K 
Published: October 2024

OBJECTIVES
To test the hypothesis that flattening of the slope of the articular eminence occurs with progressive internal derangement (ID) of the TMJ.

METHODS
MR images of 170 TMJs in 130 patients with proven disk displacement were studied. The correlation between the prevalence of a flattened articular eminence and radiological stage of ID was analysed.

RESULTS
The prevalence of a flattened articular eminence was significantly higher in the joints with advanced ID (Mann-Whitney's U-test, P &lt; 0.05).

CONCLUSIONS
It appears that a flattening of the slope of the articular eminence occurs as a result of remodeling or degenerative changes secondary to ID.
Comparative evaluation of Tuned Aperture Computed Tomography ® for the detection of mandibular fractures
Authors: Nair M K , Webber R L , Johnson M P 
Published: October 2024

OBJECTIVES
To compare the diagnostic efficacy of Tuned Aperture Computed Tomography (TACT) with conventional imaging modalities for detection of fractures of the mandible.

METHODS
Fractures were induced using blunt trauma in human defleshed mandibles. Conventional extra-oral and indirect digital images, unprocessed TACT images reconstructed from eight and 16 basis images (BI) and iteratively restored TACT images from eight and 16 BI were used for fracture evaluation. Twelve observers recorded their diagnoses using a five-point confidence rating scale. The data were analysed using ROC curve analysis.

RESULTS
Significant differences were found (P &lt; 0.0001) in the areas under the curve (Az): film, 0.6954; digital images 0.6169; TACT unprocessed images using 8 BI, 0.7420; TACT unprocessed images using 8 BI, 0.7667; TACT unprocessed images using 16 BI, 0.7730; TACT iteratively restored images using 16 BI, 0.8143. No observer-based differences were found. Fractures in the condylar and coronoid regions were more difficult to detect than those in the ramus and body of the mandible.

CONCLUSIONS
Iteratively restored TACT images generated using 16 BI had a superior diagnostic performance to all the other imaging modalities. Studies are in order to evaluate its in vivo potential.
Computer-based registration for digital subtraction in dental radiology
Authors: Lehmann T M , Gröndahl H G , Benn D K 
Published: October 2024

OBJECTIVES
(1) To review computerized a posteriori techniques for geometry and contrast registration prior to digital subtraction in dental radiography; (2) to define a uniform notation for their methodological and technical classification and based on this key code; (3) to derive criteria for successful application of computer-based a posteriori registration for routine clinical subtraction.

METHODS
All techniques are classified with respect to the (1) dimension of geometry registration; (2) origin; (3) abstraction level, and (4) linkage of features used for registration of geometry; (5) elasticity; (6) domain, and (7) parameter determination of the geometrical transform used; (8) interaction of geometrical registration; as well as (9) origin of features, (10) model of transform, and (11) interaction of procedure for contrast correction.

RESULTS
With respect to clinical practicability, superior registration techniques are based on the low level abstraction of intrinsic features for both geometry and contrast registration. By approximately linking the features, a global projective transform should be generated for geometry registration by automatic methods, while automatic contrast correction should be non-parametric. This challenge is met only by one out of 36 published algorithms. Hence, although numerous computer-based techniques have been published, only a few of them are applied more than once in practice.

CONCLUSION
The key code proposed in this paper is useful for technical classification of a posteriori registration methods in dental radiography and allows their objective comparison. Further investigations will focus on standardization of practicable procedures to evaluate the robustness of competing methods.
Thickening of the glenoid fossa in osteoarthritis of the temporomandibular joint. An autopsy study
Authors: Honda K , Larheim T A , Sano T , Hashimoto K , Shinoda K , Westesson P L 
Published: October 2024

OBJECTIVE
To evaluate the thickness of the roof of the glenoid fossa of the temporomandibular joint (TMJ) in relationship to the stage of internal derangement from autopsy material.

MATERIAL AND METHODS
The minimum thickness of the roof of the glenoid fossa was measured with a caliper in 61 TMJ autopsy specimens. Based on macroscopic examination the joints were categorized as normal (30 joints), disk displacement (eight joints), disk displacement with osteoarthritis (12 joints) and osteoarthritis with perforation of the disk or posterior attachment (11 joints). The relationship between thickness of roof of the glenoid fossa and status of the joint was analysed.

RESULTS
The roof of the glenoid fossa was on the average 0.6 mm in normal joints, 1.1 mm in joints both with disk displacement and disk displacement with osteoarthritis and 2.6 mm in joints with osteoarthritis and perforation. The difference between the normal joints and those with perforation was significant (P&lt;0.01).

CONCLUSION
Progressive remodeling with thickening of the roof of the glenoid fossa seems to be associated with perforation of the disk or posterior attachment.
Radiographic image enhancement. Part I: spatial domain techniques
Authors: Analoui M 
Published: October 2024

Abstract
Digital image enhancement techniques provide a multitude of choices for improving the visual quality of diagnostic images. Appropriate choice of such techniques is greatly influenced by the imaging modality, task at hand and viewing conditions. This sequence of two articles will provide an overview of underlying concepts, along with algorithms commonly used for radiographic image enhancement. The first article focuses on spatial domain techniques for radiographic image enhancement, with particular reference to point processing methods, histogram modification and unsharp masking.