[Evaluating multislice computed tomography for imaging coronary atherosclerosis]. / Evaluierung der Mehrzeilendetektorcomputertomographie zur Darstellung der koronaren Atherosklerose.

PURPOSE: The purpose of this study was the evaluation of multidetector-row computed tomography (MDCT) for the assessment of atherosclerotic coronary artery vessel wall changes. METHODS: In an ex vivo study, 17 human hearts were scanned with MDCT and results were compared to histopathology. Morphologic imaging criteria of MDCT for various plaque-types were developed. In a following in vivo study, 94 coronary MDCT angiograms (MDCTA) of patients with suspected coronary artery disease (CAD) were reviewed retrospectively, assessing the diagnostic value of the coronary MDCTA, and determining the number and correlations of the various plaques types as described in the ex vivo study. Additionally, volumetry of calcified and noncalcified plaque components was performed. RESULTS: In the ex vivo study, MDCT showed a high sensitivity for calcified and non-calcified plaques. Comparing the results with histopathology, characteristic image criteria could be determined for lipid-rich, fibrous and calcified plaque components. Reviewing the contrastenhanced in-vivo MDCT coronary angiographies, presence of noncalcified plaques was proven in 38% of the patients. In 5 patients with a calcium score of 0, presence of coronary atherosclerosis was proven in the contrastenhanced scan. CONCLUSIONS: MDCT is able to differentiate various plaque components in an ex vivo setting as well as invivo. Contrastenhanced MDCT of the coronary arteries allows for the detection of noncalcified plaques. In vivo volumetry of noncalcified plaques is feasible.

Quantitative assessment of carotid plaque composition using multicontrast MRI and registered histology.

MRI is emerging as a promising modality for monitoring carotid atherosclerosis. Multiple MR contrast weightings are required for identification of plaque constituents. In this study, eight MR contrast weightings with proven potential for plaque characterization were used to image carotid endarterectomy specimens. A classification technique was developed to create a tissue-specific map by incorporating information from all MR contrast weightings. The classifier was validated by comparison with micro-CT (calcification only) and with matched histological slices registered to MR images using a nonlinear warping algorithm (other components). A pathologist who was blinded to the classifier results manually segmented digitized histological images. The sensitivity of the classifier, as determined by pixel-by-pixel comparison with the pathologist's segmentation and micro-CT, was 60.4% for fibrous tissue, 83.9% for necrosis, 97.6% for calcification, and 65.2% for loose connective tissue. The corresponding values for specificity were 87.9%, 75.0%, 98.3%, and 94.9%, respectively. In conclusion, multicontrast MRI was successfully used in conjunction with a supervised classification algorithm to identify plaque components in endarterectomy specimens. Furthermore, this methodology will provide a framework for comparing different classification algorithms, and determining which combination of MR contrasts will be most valuable for in vivo plaque imaging.

[Breast calcifications. The usefulness of a standardized system for the description and assessment of the mammographic findings to improve the positive predictive value]. / Calcificazioni mammarie. Utilità di un sistema standardizzato di descrizione e valutazione dei reperti mammografici ai fini del miglioramento del valore predittivo positivo.

PURPOSE: To investigate the usefulness of a standardized reporting and data system in improving the positive predictive value of mammography in breast calcifications. MATERIALS AND METHODS: Using the Breast Imaging Reporting and Data System lexicon developed by the American College of Radiology, we defined 5 descriptive categories of breast calcifications and classified diagnostic suspicion of malignancy on a 3-grade scale (low, intermediate and high). Two radiologists reviewed 117 mammographic studies selected from those of the patients submitted to surgical biopsy for mammographically detected calcifications from January 1993 to December 1997, and classified them according to the above criteria. The positive predictive value was calculated for all examinations and for the stratified groups. RESULTS: Thirty-five of 36 cases classified as low-grade suspicion at mammography were benign at histology, while the extant one was a microinvasive lobular carcinoma in situ. Of 44 cases of intermediate-grade suspicion, 21 were benign while 23 were malignant lesions. All the 37 cases graded as highly suspicious were actually carcinomas. The positive predictive value was 0.52 for the whole series, 0.02 in the low suspicion group, 0.52 in the intermediate suspicion group and finally 1.0 in the high suspicion group. If the low suspicion cases had not undergone surgical biopsy, the positive predictive value would have been 0.74, with a single false-negative. DISCUSSION AND CONCLUSION: Defining a standardized system for assessing and describing breast calcifications helps improve the diagnostic accuracy of mammography in clinical practice.