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Results for “computational morphology”

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PubMed1977

[Computerized tomography of the facial skeleton (part II). Pathological changes (author's transl)].

The value and main task of computerized tomography in the diagnosis of benign and malignant processes in the middle and upper facial skeleton lies in its accurate demonstration of the extent of the disease; this is important in relation to the planning of treatment, prognosis and to other complementary procedures. CT is a new and potent method for the TNM classification of tumours of the nose, paransal sinuses and nasal pharynx. The ability of the CT to demonstrate deeply situated structures in the face, without disturbing overlying shadows, makes precise staging of deep tumours possible, eg. stages T2-T4. The consequences in terms of pre-treatment TNM classification are discussed. In cases of fronto-basal fractures, the CT will show particularly trauma to the orbital contents, intracranial displacement of bone fragments and cerebral trauma with or without bleeding. Suspicion of orbital involvement by benign or malignant disease is a definite indication for a CT examination. As regards the middle and upper facial skeleton, computer tomography provides information of a morphological and quantitative nature and aids in the localisation of lesions. It should be properly integrated into the conventional clinical, endoscopic and tomographic methods employed in the diagnosis of lesions of the facial skeleton.

Facial Bones↗

PubMed2003

Three-dimensional CT evaluation for endovascular abdominal aortic aneurysm repair. Quantitative assessment of the infrarenal aortic neck.

Endovascular grafting of abdominal aortic aneurysms should be offered only to those patients with suitable anatomy. This is especially true at the level of the proximal aortic neck in order to secure long-term proximal fixation. Aortoiliac anatomy is easy to understand conceptually, however, it is difficult to define and measure quantitatively. In this article, we discuss the use of three dimensional computed tomographic angiography to determine aneurysm morphology and select patients for endovascular repair. Specifically, we apply our methods to define and measure angulation of the aorta and iliac arteries. The anatomic definition of the angulation of the proximal aortic neck is emphasized.

Angiography↗

PubMedDate not supplied

Liposarcoma of the stomach.

We present a case of gastric liposarcoma, a very uncommon pathology; only nine cases have been reported in the literature. We describe the radiologic findings of this neoplasm and emphasize the correlation between computed tomography (CT) and the macroscopic morphology of the tumor, which is conditioned by its histology. In our case, CT demonstration of fatty areas within the gastric mass facilitated the diagnosis. This finding has not been described for liposarcomas of the stomach.

Adipose Tissue↗

PubMed2004

Non-invasive evaluation of atherosclerosis with contrast enhanced 16 slice spiral computed tomography: results of ex vivo investigations.

OBJECTIVE: To evaluate the diagnostic accuracy of 16 slice computed tomography (CT) in determining plaque morphology and composition in an experimental setting. The results were compared with histopathological analysis as the reference standard. METHODS: Nine human popliteal arteries derived from amputations because of atherosclerotic disease were investigated with multislice spiral CT (MSCT). Atherosclerotic lesions were morphologically classified (completely or partially occlusive, concentric, eccentric), and tissue densities were determined within these plaques. In addition, vessel dimensions were quantitatively measured. RESULTS: The results were compared with histological analysis. The concordance index kappa for morphological classification was 0.88. Plaque density (n = 51 lesions) was significantly different (p < 0.0001) between lipid rich, fibrotic, and calcified lesions (Stary stage III: n = 2, 58 (8) Hounsfield units (HU); Stary V: n = 11, 50 (21) HU; Stary VI: n = 14, 96 (42) HU; Stary VII: n = 6, 858 (263) HU; Stary VIII: n = 18, 126 (99) HU). The concordance index kappa for the classification of plaques based on density was 0.51. Vessel dimensions had a good correlation (r = 0.98). CONCLUSIONS: 16 slice CT was found to be a reliable non-invasive imaging technique for assessing atherosclerotic plaque morphology and composition. Although calcified lesions can be differentiated from non-calcified lesions, the diagnostic accuracy in further subclassifying non-calcified plaques as lipid rich and fibrotic is low, even under experimental conditions.

Contrast Media↗

PubMed2001

Computer-aided characterization of mammographic masses: accuracy of mass segmentation and its effects on characterization.

Mass segmentation is used as the first step in many computer-aided diagnosis (CAD) systems for classification of breast masses as malignant or benign. The goal of this paper was to study the accuracy of an automated mass segmentation method developed in our laboratory, and to investigate the effect of the segmentation stage on the overall classification accuracy. The automated segmentation method was quantitatively compared with manual segmentation by two expert radiologists (R1 and R2) using three similarity or distance measures on a data set of 100 masses. The area overlap measures between R1 and R2, the computer and R1, and the computer and R2 were 0.76 +/- 0.13, 0.74 +/- 0.11, and 0.74 +/- 0.13, respectively. The interobserver difference in these measures between the two radiologists was compared with the corresponding differences between the computer and the radiologists. Using three similarity measures and data from two radiologists, a total of six statistical tests were performed. The difference between the computer and the radiologist segmentation was significantly larger than the interobserver variability in only one test. Two sets of texture, morphological, and spiculation features, one based on the computer segmentation, and the other based on radiologist segmentation, were extracted from a data set of 249 films from 102 patients. A classifier based on stepwise feature selection and linear discriminant analysis was trained and tested using the two feature sets. The leave-one-case-out method was used for data sampling. For case-based classification, the area Az under the receiver operating characteristic (ROC) curve was 0.89 and 0.88 for the feature sets based on the radiologist segmentation and computer segmentation, respectively. The difference between the two ROC curves was not statistically significant.

Algorithms↗

PubMed2006

The use of 3D surface fitting for robust polyp detection and classification in CT colonography.

In this paper we describe the development of a computationally efficient computer-aided detection (CAD) algorithm based on the evaluation of the surface morphology that is employed for the detection of colonic polyps in computed tomography (CT) colonography. Initial polyp candidate voxels were detected using the surface normal intersection values. These candidate voxels were clustered using the normal direction, convexity test, region growing and Gaussian distribution. The local colonic surface was classified as polyp or fold using a feature normalized nearest neighborhood classifier. The main merit of this paper is the methodology applied to select the robust features derived from the colon surface that have a high discriminative power for polyp/fold classification. The devised polyp detection scheme entails a low computational overhead (typically takes 2.20min per dataset) and shows 100% sensitivity for phantom polyps greater than 5mm. It also shows 100% sensitivity for real polyps larger than 10mm and 91.67% sensitivity for polyps between 5 to 10mm with an average of 4.5 false positives per dataset. The experimental data indicates that the proposed CAD polyp detection scheme outperforms other techniques that identify the polyps using features that sample the colon surface curvature especially when applied to low-dose datasets.

Algorithms↗

PubMed1989

[Thin-section computed tomography of intrapulmonary metastases after surgical resection of lung cancer].

To evaluate the morphology of small peripheral intrapulmonary metastases of lung cancers, we studied thin-section computed tomography (CT) images of 12 lesions in 5 cases (1 squamous cell carcinoma, and 4 papillary adenocarcinomas). All lesions were resected, and histopathological diagnosis of them was performed in comparison with primary lesions to differentiate multiple primary lung cancers from intrapulmonary metastases. Thin-section CT images showed mildly lobulated nodules in connection with supplying pulmonary vessels, however, indented pleura and vascular convergence were less frequently seen in intrapulmonary metastases in contrast with primary lung cancers. Thin-section CT is helpful for distinguishing multiple primary lung cancers from intrapulmonary metastases in patients with a history of surgical resection for lung cancers.

Adenocarcinoma, Papillary↗

PubMedDate not supplied

CT manifestations of infectious mononucleosis.

A case of infectious mononucleosis (IM) which, on computed tomography (CT) scan, mimicked the morphologic features of lymphoma is reported. The CT findings in this case include generalized lymphadenopathy, splenomegaly, and focal low-attenuation splenic lesions in a fifty-three year old woman; these findings have not previously been described in patients with IM. This is most likely because IM is usually a clinical diagnosis confirmed by serologic testing. Imaging modalities such as CT scan have not routinely been utilized to support this diagnosis.

Diagnosis, Differential↗

PubMed1978

Computed tomographic brain scanning in intraparenchymal pyogenic abscesses.

Retrospective analysis of 25 pyogenic brain abcesses diagnosed by computed tomography (CT) revealed relatively specific morphologic characteristics of these infections. The ability to obtain an early accurate diagnosis resulted in a dramatic decrease in patient morbidity and mortality. Repeated examinations by CT permitted close monitoring of the response of the abscess to antibiotic therapy. In some instances the need for surgical intervention was eliminated or the surgical approach was modified as a result of these studies.

Actinomycosis↗

PubMed1999

Non-invasive assessment of bone quality.

A morphological filter and pipeline analysis was applied to computed radiographs (CR) to abstract the geometrical characteristics of the trabecular pattern and to analyze bone mechanical properties. By applying a morphological filter to the CR images, trabecular patterns were divided into 8 subset groups (n=O through 7) by the trabecular thickness. Sumset images were also derived from the thicker trabeculae group (n=2-5, 3-6, and 4-7) to examine the criteria relating the percentage of thicker trabeculae to the strength of the bone. A method to analyze the bone mechanical properties was developed, based on the hypothesis that data of connective line segments were loaded mechanically. By this method, trabeculae were analyzed in the fifth lumbar vertebrae from etidronic acid-treated and non-treated ovariectomized osteoporosis rat models, and in human third lumbar vertebrae. Consequently, it was shown that total loss of bone mass accompanied a reduction of consecutive trabecular number in the rat osteoporosis model, especially in parts of the bone having thick trabeculae. The reduction in number of connective trabeculae, from one cortical side to the other, occurred at a similar rate, along both the craniocaudal and anteroposterior axes in the vertebral bodies of the experimental osteoporosis rats. In the dynamic study with human third vertebral blocks, no significant correlation was observed between the bone mineral density of the bone specimens and their ultimate strength (R2=0.093). In contrast, the abstracted percentage of thicker trabeculae, derived from the sumset (n=2-5) images, showed a strong correlation with bony mechanical properties (Young's modulus: R2=0.915, maximum point load: R2=0.815). The result calculated by this methodology can serve as an excellent index to indicate bone strength under non-destructive, living conditions.

Aged↗

PubMed2026

A Boveri perspective on cancer biomarker testing using artificial intelligence.

Artificial intelligence (AI) can predict genomic alterations from histology, yet its adoption is slowed by a lack of trust. We argue that deliberate morphology (i.e., a cognitive understanding of histological features supported by standardized annotations) creates a bidirectional feedback loop between clinical practice and model outputs.We translate these observations into an actionable hypothesis for clinical and computational teams: that by enhancing explainability, deliberate morphology could facilitate the responsible deployment of AI biomarkers in oncology.

Journal Article↗

PubMed2002

Computerized detection of pulmonary nodules in chest radiographs based on morphological features and wavelet snake model.

We have developed a new computer-aided diagnosis scheme for automated detection of lung nodules in digital chest radiographs based on a combination of morphological features and the wavelet snake. In our scheme, two processes were applied in parallel to reduce the false-positive detections after initial nodule candidates were selected. One process consisted of adaptive filtering for enhancement of nodules and suppression of normal lung structures, followed by extraction of conventional morphological features. The other process consisted of a novel approach for elimination of false positives called the edge-guided wavelet snake model. In the latter process, multiscale edges of the candidate nodules were extracted to yield parts of the nodule boundaries. A wavelet snake was then used for fitting of these multiscale edges for approximation of the true boundaries of nodules. A boundary feature called the weighted overlap between the snake and the multiscale edges was calculated and used for elimination of false positives. Finally, the weighted overlap and the morphological features were combined by use of an artificial neural network for efficient reduction of false positives. Our scheme was applied to a publicly available database of digital chest images for pulmonary nodules. Receiver operating characteristic analysis was employed for evaluation of the performance of each process in the scheme. The combined features yielded a large reduction of false positives, and thus achieved a high performance in discriminating between true and false positives. These results show that our new method, in particular the false-positive reduction method based on the wavelet snake, is effective in improving the performance of a computerized scheme for detection of pulmonary nodules in chest radiographs.

Adult↗

PubMed2006

Relationship between CT volumetry and functional liver volume using technetium-99m galactosyl serum albumin scintigraphy in patients undergoing preoperative portal vein embolization before major hepatectomy: a preliminary study.

To clarify the relationship between morphological measurements of hepatic volume by computed tomography (CT-vol) and functional volume (RI-vol) by technetium-99m galactosyl human serum albumin (99mTc-GSA) scintigraphy, and its clinical significance, we examined 16 patients with a background liver status of either normal liver function (n=4), chronic hepatitis or cirrhosis (n=7), or obstructive jaundice (n=5). In five patients who underwent preoperative portal vein embolization (PVE), volumetric measurement was performed 2 weeks after PVE. The mean values of CT-vol and RI-vol of the right lobe were 692+/-147 cm3 (66.1+/-10.7%) and 668+/-159 cm3 (67.8+/-13.2%), respectively, and those of the left lobe were 329+/-138 cm3 (33.9+/-10.6%) and 328+/- 170 cm3 (32.2+/-13.2%), respectively. There were no significant differences in the volume measurements between the two volumetric techniques. Correlations between CT-vol and RI-vol in the right and left lobes were positive and significant (r=0.912 and 0.903, respectively; both P's<0.001). The mean values of post-PVE CT-vol and RI-vol of the right lobe in five patients were significantly different (628+/-149 and 456+/-211 cm3, respectively; P=0.033). However, the mean values of post-PVE CT-vol and RI-vol of the left lobe were not different (496+/-124 and 483+/-129 cm3, respectively). We propose that volumetric measurement by 99mTc-GSA scintigraphy is useful for detecting changes in functional volume of individual lobes of the liver and is a more dynamic method compared with detection of morphological changes by CT scan.

Adult↗

PubMed1979

Computed tomographic positive contrast peritoneography.

Despite the use of intravenous and oral contrast material and antiperistaltic pharmaceuticals, abdominal computed tomography has limitations in the morphological study of the gastrointestinal tract, retroperitoneum, and pelvis. To better define these regions, positive contrast material was infused into the peritoneal space prior to abdominal CT. Results included: improved visualization of the peritoneal cavity and its contents; evident demarcation between the retroperitoneal space and intraperitoneal structures; sharp delineation of serosal surfaces of the bowel and solid viscera; and an obvious distinction between impinging bowel loops and pelvic organs.

Adult↗

PubMed1997

Abnormal cerebral perfusion in chronic methamphetamine abusers: a study using 99MTc-HMPAO and SPECT.

1. Cerebral blood flow of nine methamphetamine abusers with technetium-99m-hexamethylpropyleneamine oxime (HMPAO) and single photon emission computed tomography (SPECT) as well as morphological examination with magnetic resonance imaging (MRI) were investigated. 2. Six of these subjects exhibited multiple focal perfusion deficits in cerebral cortices without abnormalities in MRI including cerebral atrophy and/or infarctions. 3. Cerebral perfusion deficits were detected in methamphetamine abusers even after a long abstinence period, suggesting that vascular changes were irreversible to some degree. 4. HMPAO SPECT study appeared to be sensitive to the detection of cerebral perfusion abnormalities in drug abusers.

Adolescent↗

PubMed2006

Aortic neck morphology after endovascular repair of descending thoracic aortic aneurysms.

BACKGROUND: Endovascular repair has emerged as a less-invasive treatment for descending thoracic aortic (DTA) aneurysms. However, the durability of this procedure relies on the stability of proximal and distal fixation sites. This study analyzes 3 years of computed tomography (CT) data on aortic neck morphology after endovascular DTA aneurysm repair. METHODS: Between 1999 and 2001, 139 patients underwent successful endovascular DTA repair as part of a prospective, multicenter clinical trial investigating the Gore TAG thoracic endoprosthesis. Contrast-enhanced, high-resolution CT scans were obtained at 1 (baseline), 12, 24, and 36 months and submitted to an independent core laboratory for image analysis. The aorta was carefully measured by using computerized planimetry and a standardized protocol. Neck diameter was measured at 10-mm intervals for 2 cm above and below the aneurysm and correlated with graft migration and endoleak. RESULTS: The mean proximal neck diameter increased from a baseline of 30.2 +/- 4.6 mm to 32.0 +/- 4.3 mm at 36 months (P <.05), and the annual diameter increase was 0.8, 0.4, and 0.6 mm at 12, 24, and 36 months. The mean distal neck diameter increased from 29.4 +/- 3.8 mm to 32.1 +/- 5.0 mm at 36 months (P <.05), and the annual diameter increase was 1.1, 0.4, and 1.2 mm at 12, 24, and 36 months. At 36 months, freedom from neck dilation of > or =5 mm was 87%, and freedom from migration of > or =10 mm was 83%. An endoleak was present in 11 (9%) of 122 patients at baseline, 7 (7%) of 96 at 12 months, 6 (9%) of 68 at 24 months, and 1 (3%) of 33 at 36 months. Neck dilation was not associated with graft migration or endoleak. CONCLUSIONS: Three years after endovascular repair of DTA aneurysms, there is progressive enlargement of the proximal and distal aortic necks. Although uncommon for patients to develop significant neck dilation, when it does occur, it is not associated with graft migration or endoleak. Continued surveillance of aortic neck morphology after descending thoracic aneurysm endografting is recommended.

Aorta, Thoracic↗

PubMed2001

Development of the equine brain motor system.

The purpose of the present study was to demonstrate the structural maturation of the horse brain in the critical period of development emergence of coordinated locomotion. Equine brains from 14 days before expected birth to adulthood were fixed in formaldehyde and embedded in paraffin. After taking the outer parameters of the brains, full series of large-area coronal sections were prepared on a special microtome and stained with Nissl's cresyl violet and Haidenhain's iron-haematoxylin. Microscopic images of sections were digitized and were subjected to computer-aided image analysis. The gross morphology of the brains and the image analysis of histological preparations suggest that in the perinatal period studied there is no substantial increase in brain size and mass, while the amount of Nissl substance and myelin grows rapidly till postnatal day 45. Then a relative decrease of both is observed till adulthood accompanied by a doubling of brain size and mass. It is concluded that during the maturation of the equine brain, decisive changes of the motor system such as up-regulation of protein sysnthesis and full myelination of motor tracts takes place during the critical period of onset of coordinated locomotion.

Animals↗

PubMed2006

Quantitative and qualitative assessment of morphology in sagittal synostosis: mid-sagittal vector analysis.

Consensus remains lacking regarding the optimal surgical treatment modality for sagittal synostosis. There is, however, wide agreement that objective analytical methods are required to demonstrate the characteristic morphology of the condition and to substantiate the benefits of specified surgical techniques. Simple calculated anthropomorphic indices, such as the cranial index, are commonly used but fail to provide satisfactory representation of morphology, which is far more complex than can be represented by its simple length-width ratio. Techniques to provide more comprehensive, yet practical, assessment of morphology are needed for analytic purposes. Herein, we introduce vector analysis as an objective, computed tomography (CT)-based morphometric technique for assessment of cranial morphology; this work represents the first application of the technique mid-sagittal vector analysis (MSVA). MSVA is a single plane application that was devised to address dysmorphology in sagittal synostosis. It was our hypothesis that MSVA would quantitatively and qualitatively depict preoperative morphology and postoperative correction in specific regions. Sixteen patients undergoing cranial reshaping surgery for sagittal synostosis were included in the study. All patients underwent routine preoperative and 1 year postoperative CT scans, from which the MSVA was derived. MSVA is a radial vector analysis in which distances to the cranial surface are measured from a single reference point origin in the sagittal plane. Preoperative morphology, characterized by respective vectors, was analyzed in three regions: the frontal, vertex, and occipital regions. Comparison with postoperative paired data was conducted for each patient. The analysis of postoperative change demonstrated (1) decrease in prominence in the frontal and occipital regions, (2) increase in height and forward translation of the vertex, and (3) ability to distinguish and qualify frontal versus occipital bossing and correction thereof. We conclude that the longitudinal differences associated with scaphocephaly are well characterized and differentiated by MSVA. Quantitative and qualitative assessment identifies three relevant regions affected by the condition and its treatment: the frontal, vertex, and occipital regions. The transverse dimension is not addressed in this single plane analysis; a more comprehensive application will require additional planes of analysis and the development of a normative database.

Cephalometry↗