Centripetal Enhancement Research Articles

Epithelioid Hemangioendothelioma of the Liver: Helical CT Findings

Purpose: To describe the morphologic features and enhancement patterns of the helical computed tomography (CT) observed in patients with epithelioid hemangioendothelioma (EH) of the liver. Materials and Methods: Seven patients (four men and three women; mean age, 41 years) with pathologically proven EHs underwent monophasic (n=2), biphasic (n=2) or triphasic (n=3) helical CT, and the findings were retrospectively analysed. The morphologic features to which attention was directed were tumor number, size, location, shape, margin, surface, the presence of adjacent capsular retraction, vascular encasement and confluent mass formation, while the enhancement pattern was examined in terms of the appearance and degree of enhancement during the arterial or portal phase, and enhancement change during the portal and equilibrium phases. Results: Six patients had multiple tumors, and one had a single lesion. The maximon diameter of these tumors ranged from 0.5 to 12.0 (mean, 3.2) cm, and almost all occurred in the peripheral portion of the liver. The shape, margin and surface features of the tumors varied: in four patients, the margin was poorly defined and the surface was smooth, while in five, adjacent capsular retraction was observed. Vascular encasement was noted in five of six patients with hepatic vessels abutting the tumors, and in all three who were follow up, the growth pattern involved confluent mass formation. In all patients, many tumors showed either nodular (n=3) or irregular (n=4) peripheral enhancement. In all five patients who underwent multiphasic CT, centripetal enhancement was demoustrated. Conclusion: Our results disclosed that most patients with EH had multiple tumors, and that almost all were located in the peripheral portion of the liver and involved capsular retraction. The other common CT findings were vascular encasement and a centripetal enhancement pattern. When these CT findings are observed in patients with hepatic tumors, EH should be included in the differential diagnosis.

Radiologists' performance in the diagnosis of liver tumors with central scars by using specific CT criteria.

To determine the performance of radiologists with differing levels of expertise in the diagnosis of the most common types of liver tumors with central scars (ie, focal nodular hyperplasia [FNH], fibrolamellar hepatocellular carcinoma [HCC], and large hepatic hemangioma) by using specific computed tomographic (CT) findings. Review of medical records at the University of Pittsburgh Medical Center identified patients with a total of 64 liver tumors that had central scars-including 29 cases of FNH, 20 fibrolamellar HCCs, and 15 large (>3.5 cm in diameter) hemangiomas-and with CT scans available for review. Retrospective review of these scans was performed individually by six radiologists who were blinded to the diagnosis, including two faculty abdominal radiologists, one abdominal imaging fellow, and three radiology residents. Individual performance was evaluated by means of receiver operating characteristic analysis, and interobserver agreement was measured by using the Cronbach alpha. Individual CT findings that may allow differentiation of tumor types were identified with the Kruskal-Wallis test. CT allowed good to excellent interobserver agreement in the diagnosis of tumor type and in recognition of differential findings among the three types. The individual accuracy of diagnosis was very good, with the average area under the receiver operating characteristic curve ranging from 0.81 to 0.90. Although the faculty radiologists performed the best, the differences in performance between the subgroups of readers and the levels of confidence in diagnosis were not statistically significant. The diagnosis of fibrolamellar HCC was the most accurate and had the highest sensitivity, followed by FNH and large hemangioma. Clinical and CT findings that were found to be statistically significant in differentiating tumor types were patient age and sex, tumor size larger than 10 cm, width of tumor scars, invasion of vessels, nodular centripetal enhancement, marked hyperattenuation on arterial phase images, lymphadenopathy, heterogeneity, extrahepatic metastases, surface lobulation, calcification, and isoattenuation with liver tissue on portal venous phase images. CT allows accurate differentiation of the most common types of liver tumors with central scars, including FNH, fibrolamellar HCC, and large hemangioma.

Discussion

We report the MR findings of an endometrial stromal sarcoma. The uterus was enlarged and completely replaced by neoplastic tissue, with full-thickness myometrial infiltration. It had isointense signal on T1- and irregularly hyperintense signal on T2-weighted images and the dynamic study with intravenous gadoteridol showed centripetal enhancement. This sarcomatous-like pattern correlates well with the pathologic and CT findings reported in the literature.

Mediastinal Castleman disease: CT findings.

Our objective was to characterize the CT findings of mediastinal Castleman disease. We reviewed the CT findings of mediastinal Castleman disease in 10 patients. In nine cases of hyaline-vascular type Castleman disease, lymph nodes were 2-7 cm in diameter and located in the hilum in six patients, superior mediastinum in two patients, and posterior mediastinum in one patient. On CT the tumors were well-demarcated round masses showing dense homogeneous enhancement after contrast medium injection. Dynamic CT in one case showed gradual centripetal enhancement of the mass. In one case of hyaline-vascular type Castleman disease, lumpy and irregular calcifications were noted in the center of the mass. In the one case of plasma cell type Castleman disease, multiple small homogeneously enhancing nodes were found in the mediastinal and supraclavicular area. CT findings may suggest the preoperative diagnosis of mediastinal Castleman disease.

Dynamic breath-hold multiplanar spoiled gradient-recalled MR imaging with gadolinium enhancement for differentiating hepatic hemangiomas from malignancies at 1.5 T.

To compare the enhancement patterns of focal liver lesions at dynamic breath-hold gadolinium-enhanced multiplanar spoiled gradient-recalled (SPGR) magnetic resonance (MR) imaging with T2 relaxation times in the differentiation of liver hemangiomas from malignancies. Forty-seven patients with focal liver lesions underwent MR imaging with spin-echo and gadolinium-enhanced multiplanar SPGR techniques. T2 relaxation times and enhancement patterns were compared for accuracy in liver lesion characterization. Enhancement patterns allowed better characterization of liver lesions than did T2 relaxation times. Only specific patterns of contrast enhancement indicated a hemangioma. Although 18 of the 33 malignancies and 10 of the 12 hemangiomas showed progressive centripetal hyperintense enhancement, only hemangiomas filled in with hyperintense peripheral nodules. Malignancies often filled in with hyperintense thick rinds. Gadolinium-enhanced multiplanar SPGR imaging allows more accurate characterization of liver lesions than does T2 relaxation time.