Purpose:To elucidate whether apparent diffusion coefficient (ADC) values calculated from echo-planar diffusionweighted MR imaging (EPDWI) are useful in the differential diagnosis of ovarian cystic masses. Materials and Methods: EPDWI was performed in 131patients with ovarian cystic masses (54 mature cystic teratomas, 35 endometrial cysts, four other benign cysts, 14 benign neoplasms, and 24 malignant neoplasms). The areas of the highest signal intensity on EPDWI (b ϭ 1000 seconds/mm 2 ) and the lowest ADC values within the cystic component were evaluated. Results:On qualitative and quantitative analyses, mature cystic teratomas tended to show higher signal intensity and had areas of lower ADC values than endometrial cysts and other benign and malignant neoplasms (P Ͻ .005). In vitro scanning of the cystic contents of mature cystic teratomas confirmed that high signal on DWI or low ADC value was attributable to the keratinoid substance within the tumors. The difference in ADC between malignant and benign lesions were significant when mature cystic teratomas and endometrial cysts were included, but was not significant when they were excluded. Conclusion:The ADC value may add useful information to the differential diagnosis of ovarian cystic masses in limited populations, such as those with mature cystic teratomas with a small amount of fat. DIFFUSION-WEIGHTED IMAGING (DWI) and the calculated apparent diffusion coefficient (ADC) were originally used to demonstrate early ischemic change in brain tissue by depicting cytoplasmic edema (1). They have also been applied to differentiate brain tumors, particularly in the diagnosis of epidermoid and lymphoma (2-6). A high signal on DWI or a low ADC value of these tumors have been attributed to intratumoral keratinoid substance in the former, and high cellularity and a high nuclear-to-cytoplasm (NC) ratio without interstitial edematous change in the latter (2-6). Both of these conditions restrict Brownian movement of the free water molecules within the tumor. The ability of high-speed echo-planar imaging (EPI) to minimize artifacts due to respiratory motion has extended the application of DWI and ADC to the diagnosis of breast lesions (7-10) and prostate carcinomas (11,12), and promising preliminary results have been reported. However, there is controversy regarding the usefulness of this technique in cystic ovarian tumors (13-16), particularly as applied to differentiating benign from malignant lesions.In this study we applied echo-planar DWI (EPDWI) and ADC values to 131 cystic ovarian masses and assessed their potential usefulness in the differential diagnosis. MATERIALS AND METHODS SubjectsBetween September 2000 and December 2003, 322 consecutive women underwent MRI for evaluation of known ovarian lesions. Of these patients, 131 (11-75 years old, mean ϭ 33.9 years) underwent surgical resection within 2 weeks after the MRI was performed. Of the 131 patients, 102 had a lateral lesion and 29 had bilateral lesions. In the bilateral cases, the largest lesion was selected for...

No abstract

The degree of enhancement on delayed-phase CT scans is a useful indicator for prediction of the prognosis of patients with mass-forming ICC.

Branch duct type IPMTs grow slowly and can be monitored without operation provided that the tumor shows no associated MPD dilatation or filling defect.

The area of peritumoral hemodynamic change in HCC patients with minute portal invasion (group 1) may be larger than in those without it (group 0), especially when tumors are small.