T2-weighted magnetic resonance (MR) imaging has been widely used for pretreatment work-up for prostate cancer, but its accuracy for the detection and localization of prostate cancer is unsatisfactory. To improve the utility of MR imaging for diagnostic evaluation, various other techniques may be used. Dynamic contrast material-enhanced MR imaging allows an assessment of parameters that are useful for differentiating cancer from normal tissue. The advantages of this technique include the direct depiction of tumor vascularity and, possibly, obviation of an endorectal coil; however, there also are disadvantages, such as limited visibility of cancer in the transitional zone. Diffusion-weighted imaging demonstrates the restriction of diffusion and the reduction of apparent diffusion coefficient values in cancerous tissue. This technique allows short acquisition time and provides high contrast resolution between cancer and normal tissue, but individual variability in apparent diffusion coefficient values may erode diagnostic performance. The accuracy of MR spectroscopy, which depicts a higher ratio of choline and creatine to citrate in cancerous tissue than in normal tissue, is generally accepted. The technique also allows detection of prostate cancer in the transitional zone. However, it requires a long acquisition time, does not directly depict the periprostatic area, and frequently is affected by artifacts. Thus, a comprehensive evaluation in which both functional and anatomic MR imaging techniques are used with an understanding of their particular advantages and disadvantages may help improve the accuracy of MR for detection and localization of prostate cancer.

Biphasic helical CT may be useful in differentiating AML with minimal fat from RCC, with homogeneous tumor enhancement and prolonged enhancement pattern being the most valuable CT findings.

Ovarian teratomas can be associated with various complications and demonstrate a wide spectrum of clinical and imaging features. The complications include torsion (16% of ovarian teratomas), rupture (1%-4%), malignant transformation (1%-2%), infection (1%), and autoimmune hemolytic anemia (<1%). These complications require different therapeutic strategies; therefore, timely and accurate diagnosis of these complications is important for optimal patient treatment. In cases of complicated ovarian teratomas, the clinical manifestations provide only limited information and often overlap with those of other diseases. Furthermore, ovarian teratomas may have unusual clinical and imaging manifestations, thereby leading to misdiagnosis. These unusual manifestations include immature teratomas, monodermal teratomas (struma ovarii), combination tumors and collision tumors containing teratomas, and mature cystic teratomas without demonstrable fat or with pure fatty components. To provide adequate treatment and prevent misdiagnosis, it is necessary to be familiar with the imaging findings of both the complications and the unusual manifestations of ovarian teratomas.

Purpose:To investigate the feasibility of diffusion-weighted imaging (DWI) in the differentiation of metastatic from nonmetastatic lymph nodes. Materials and Methods:In 125 patients who underwent lymph node dissection for uterine cervical cancer, DWI was performed at b value of 0 and 1000 s/mm 2 . By referring to the surgical maps of the pelvic lymph nodes, the apparent diffusion coefficient (ADC) was compared in the metastatic and nonmetastatic lymph nodes, and receiver-operatingcharacteristics analysis was performed to evaluate the diagnostic performance of the ADC in differentiating metastatic from nonmetastatic lymph nodes. Results:The ADC were significantly lower in the metastatic lymph nodes (0.7651 ϫ 10 Ϫ3 mm 2 /s Ϯ 0.1137) than in the nonmetastatic lymph nodes (1.0021 ϫ 10 Ϫ3 mm 2 /s Ϯ 0.1859; P Ͻ 0.001). The area-under-the-curve of ADC for differentiating metastatic from nonmetastatic lymph nodes, was 0.902. The sensitivity and specificity of ADC for differentiating metastatic from nonmetastatic lymph nodes, were 87% for the ADC and 80%, respectively. Conclusion:DWI is feasible for differentiating metastatic from nonmetastatic lymph nodes in patients with uterine cervical cancer.

Double-echo GRE chemical shift MR imaging can be used to differentiate AML with minimal fat from other renal neoplasms.

Although definite radiologic differentiation from malignancy is not clearly possible, we suggest that familiarity with the manifestations of inflammatory pseudotumor can help avoid unnecessary radical surgery before histopathologic proof of malignancy is obtained.

Purpose:To evaluate the usefulness of the wash-in rate based on dynamic contrast-enhanced (DCE) MRI for the detection and localization of prostate cancer. Materials and Methods:In 53 patients, the wash-in rate was measured in the cancer area and in three normal areas (the peripheral zone, inner portion of the transitional zone, and outer portion of the transitional zone). On the basis of these data, parametric imaging was generated and then its accuracy for cancer detection and location was evaluated compared to that of T2-weighted imaging without the use of an endorectal coil. For that purpose the entire prostate was divided into 18 segments. Results:The wash-in rate value was greater in cancer tissue (9.2/second) than in three normal tissues (3.3/second, 6.7/second, and 3.2/second, respectively; P Ͻ 0.001). The sensitivity and specificity were greater on parametric imaging of the wash-in rate compared to T2-weighted imaging in the entire prostate (96% and 82% vs. 65% and 60%, respectively) and the peripheral zone (96% and 97% vs. 75% and 53%; P Ͻ 0.05). In the transitional zone, the sensitivity was greater on parametric imaging (96%) than on T2-weighted imaging (45%; P ϭ 0.016), but the specificity was similar (51% vs. 73%; P ϭ 0.102). Conclusion:The wash-in rate based on DCE-MRI is a useful parameter for prostate cancer detection and localization.

No abstract