Fat-containing nodules in the cirrhotic liver: chemical shift MRI features and clinical implications.
OBJECTIVE
The purpose of this study was to determine the ability of MRI to predict malignancy in fat-containing nodules in the cirrhotic liver.


METHODS
In 38 patients with cirrhotic livers, focal lesions > or = 5 mm containing fatty components were identified on chemical shift gradient-echo MRI. Positive predictive values (PPVs) for benignity and malignancy were calculated on the basis of lesion size, T1-weighted hypointensity, T2-weighted hyperintensity, and arterial hypervascularity on the initial MR images. The number of the fatty nodules (group A, up to 4; group B, numerous) in individual patients was also correlated with the malignant potential of the lesions that were verified pathologically or by follow-up imaging studies.


RESULTS
In 31 group A patients, 21 (47%) of the 45 lesions showed a malignant course, and their mean diameter (18.8 mm) was larger (p = 0.007) than that (10.5 mm) of benign lesions. In seven group B patients, all 35 lesions (the five largest lesions in each patient; mean diameter, 7.8 mm) proved to be benign. The PPV of larger (> or = 15 mm) fat-containing nodules for malignancy was 85% (11/13 lesions). Six (55%) of 11 immediately diagnosed hepatocellular carcinomas were entirely hypointense on unenhanced in-phase T1-weighted images. The PPV of T2-weighted hyperintensity and arterial hypervascularity for the diagnosis of malignancy was 100% in group A patients.


CONCLUSIONS
In the cirrhotic liver, large size (> or = 15 mm) and T1-weighted hypointensity on in-phase images strongly suggest malignancy of the fat-containing nodules. The presence of numerous nodules < 1 cm suggests that the lesions are benign.
Yu
Jeong-Sik
JS
Department of Radiology, Yonsei University College of Medicine, YongDong Severance Hospital, 146-92 Dogok-Dong, Gangnam-Gu, Seoul 135-720, South Korea. yjsrad97@yumc.yonsei.ac.kr
Chung
Jae-Joon
JJ
Kim
Joo Hee
JH
Kim
Ki Whang
KW
D000328:Adult; D000368:Aged; D005234:Fatty Liver / Q000150:complications / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008103:Liver Cirrhosis / Q000150:complications / Q000175:diagnosis*; D008113:Liver Neoplasms / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies