MATERIALS AND METHODS. Fifty-two patients with extrahepatic primary malignant tumors underwent 1.5-T MRI that included DW EPI and the following variants of T2-weighted TSE techniques: breath-hold fat-suppressed HASTE, breath-hold fat-supressed TSE, respiration-triggered fat-suppressed TSE, breath-hold STIR, and respiration-triggered STIR. Images were reviewed independently by two blinded observers who used a 5-point confidence scale to identify lesions. Results were correlated with surgical and histopathologic findings and follow-up imaging findings. The accuracy of each technique was measured with free-response receiver operating characteristic analysis.

RESULTS. A total of 118 hepatic metastatic lesions (mean diameter, 12.8 mm; range, 3–84 mm) were evaluated. Accuracy values were higher (p < 0.001) with DW EPI (0.91–0.92) than with the T2-weighted TSE techniques (0.47–0.67). Imaging with the HASTE sequence (0.47–0.52) was less accurate (p < 0.05) than imaging with the breath-hold TSE, breath-hold STIR, respiration-triggered TSE, and respiration-triggered STIR sequences (0.59–0.67). Sensitivity was higher (p < 0.001) with DW EPI (0.88–0.91) than with T2-weighted TSE techniques (0.45–0.62). For small (≤ 10 mm) metastatic lesions only, the differences in sensitivity between DW EPI (0.85) and T2-weighted TSE techniques (0.26–0.44) were even more pronounced.

CONCLUSION. DW EPI was more sensitive and more accurate than imaging with T2-weighted TSE techniques. Because of the black-blood effect on vessels and low susceptibility to motion artifacts, DW EPI was particularly useful for the detection of small (≤ 10 mm) metastatic lesions.

MATERIALS AND METHODS. Radiology and pathology records from January 1999 to March 2007 were reviewed to identify 24 patients (22 women and two men; mean age, 40 years) with a pathology-proven diagnosis of hepatic adenoma (mean size ± SD, 7.2 ± 3.7 cm) who underwent helical contrast-enhanced CT (n = 23) and/or gadolinium-enhanced MRI (n = 8). The control group was composed of 24 patients of similar age and sex (21 women and three men; mean age, 43 years) with hepatic hemangioma who underwent CT or MR evaluation during the same time period. Two radiologists independently interpreted the imaging studies to determine the number of lesions and whether steatosis was present. The difference in prevalence of steatosis between the adenoma group versus the control group and the difference between patients with a single hepatic adenoma versus those with multiple hepatic adenomas were assessed (chi-square test).

RESULTS. Hepatic steatosis was present in 14 of 24 patients (58%) with hepatic adenoma versus seven of 24 patients (29%) with hemangioma (p = 0.042). Steatosis was more common in patients with multiple hepatic adenomas (9/11, 82%) than in those with a single hepatic adenoma (5/13, 38%) (p = 0.047).

CONCLUSION. Hepatic adenomas occur more frequently and more often are multiple in patients with hepatic steatosis.

MATERIALS AND METHODS. We retrospectively identified 39 patients (25 men and 14 women) with suspected isolated hepatic metastases from colorectal cancer who underwent FDG PET/CT. The CT protocol included acquisition of unenhanced and multiphase contrast-enhanced CT images through the liver. At two separate sittings, four readers (two radiologists and two nuclear medicine physicians) noted and characterized all hepatic lesions in consensus, first based on PET and unenhanced CT images and later based on PET and contrast-enhanced CT images. The nature of detected lesions was established by histopathologic or clinicoradiologic correlation.

RESULTS. A total of 178 hepatic lesions were identified, consisting of 137 metastases and 41 benign lesions. Using lesion-based analyses with Obuchowski's method for paired observations, 172 of 178 lesions (97%) were detected at PET/contrast-enhanced CT compared with only 135 of 178 (76%) at PET/unenhanced CT (p = 0.0004). Specifically, 114 of 137 (83%) hepatic metastases were detected on PET/contrast-enhanced CT compared with 92 of 137 (67%) on PET/unenhanced CT (p = 0.012). One hundred thirty-one of 178 lesions (73%) were accurately characterized at PET/contrast-enhanced CT compared with 101 of 178 (57%) at PET/unenhanced CT (p = 0.004).

CONCLUSION. IV iodinated contrast material administration improves the detection of hepatic metastases and the characterization of focal hepatic lesions at PET/CT.

CONCLUSION. Understanding the characteristic appearances of primary gallbladder carcinoma at multiple imaging modalities can facilitate diagnosis and enable more accurate staging for triage to extended resection or an alternate therapy.

CONCLUSION. Hilar cholangiocarcinoma is a primary malignant tumor typically located at the confluence of the right and left ducts within the porta hepatis. Staging of hilar cholangiocarcinoma with various imaging techniques is crucial for management, and a comprehensive approach is needed for accurate preoperative assessment.

CONCLUSION. Solitary necrotic nodules are usually small, solitary lesions, mainly located under the liver capsule of the right lobe. They are hypoechoic on sonography, hypoattenuating on CT, have low signal intensity on both T1- and T2-weighted MRI with lack of enhancement after IV contrast administration, and at follow-up have a tendency to show calcification and involution toward reduction in size.