Background: Gas in the mesenteric or portal veins (PVG) is an uncommon entity. It was first described only in patients with mesenteric ischemia and bowel gangrene. Later, several reports described other causes for PVG in which conservative treatment was successful. In the past, the diagnosis was made by vague signs in abdominal plain films. Since the era of computerized tomography (CT) scan the diagnosis became more objective, but nevertheless it is still an elusive entity. Our objective was to relate clinical and CT findings with outcome of patients with PVG, and to determine the indications for surgical treatment. Methods: Six-year records of patients from one general hospital with CT scan findings of gas in the mesenteric or portal veins were retrospectively studied, together with details of the clinical presentation, hospital course and outcome. Results: Between 1995 and 2000, 12 patients with findings of mesenteric and portal vein gas were identified. In 7 of 12 patients (58%) PVG developed secondary to ischemia of the small or large bowel, with mortality of 86%. Metabolic acidosis was the prominent laboratory finding. Pneumatosis intestinalis was present in all of these patients. Two patients with PVG had inflammatory bowel disease and both recovered with conservative management. Another 2 patients who were treated conservatively died. One patient had severe pancreatitis and died 2 weeks after PVG was diagnosed, from septic complications, while the other patient admitted with septic shock, died of multiorgan failure. In the last patient, PVG was diagnosed in a CT scan performed to investigate fever of unknown origin. She survived with no specific treatment. Conclusion: We suggest that patients in whom PVG is found by CT scan should be treated according to their clinical status, and underlying disease. Patients suspected of having an ischemic mesenteric event should be immediately explored.

Dynamic contrast enhanced MRI is applied as an adjuvant tool for breast cancer detection, diagnosis, and follow-up of therapy. Despite improvements through the years in achieving higher spatial and temporal resolution, it still suffers from lack of scanning and processing standardization, and consequently, high variability in the radiological evaluation, particularly differentiating malignant from benign lesions. We describe here a hybrid method for achieving standardization of the radiological evaluation of breast dynamic contrast enhanced (DCE)-magnetic resonance imaging (MRI) protocols, based on integrating the model based three time point (3TP) method with principal component analysis (PCA). The scanning and image processing procedures consisted of three main steps: 1. 3TP standardization of the MRI acquisition parameters according to a kinetic model, 2. Applying PCA to test cases and constructing an eigenvectors' base related to the contrast-enhancement kinetics and 3. Projecting all new cases on the eigenvectors' base and evaluating the clinical outcome. Datasets of overall 96 malignant and 26 benign breast lesions were recorded on 1.5T and 3T scanners, using three different MRI acquisition parameters optimized by the 3TP method. The final radiological evaluation showed similar detection and diagnostic ability for the three different MRI acquisition parameters. The area under the curve of receiver operating characteristic analysis yielded a value of 0.88 ± 0.034 for differentiating malignant from benign lesions. This 3TP + PCA hybrid method is fast and can be readily applied as a computer aided diagnostic tool of breast cancer. The underlying principles of this method can be extended to standardize the evaluation of malignancies in other organs.

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