Nonhypervascular hypoattenuating nodules depicted on either portal or equilibrium phase multiphasic CT images in the cirrhotic liver

OBJECTIVE. The objective of this study was to investigate the outcome and clinical implications of nonhypervascular hypoattenuating nodules observed on portal or equilibrium phase CT images of cirrhotic livers. MATERIALS AND METHODS. One hundred one cirrhotic patients (male: female = 69: 32) with hypoattenuating nodules observed on initial portal or equilibrium phase CT images were retrospectively evaluated by follow-up CT performed 6-66 months after the initial CT examination. Depending on the background nodularity, patients were separated into macronodular (n = 33, 288 nodules) and micronodular (n = 68, 346 nodules) cirrhotic groups. Each nodule was categorized as category I (enlarged) or category II (stable). Nodule categories were correlated with the initial lesion size and the pattern of background cirrhosis. RESULTS. The frequency of category I nodules was higher in patients with micronodular cirrhosis (40%) than in those with macronodular cirrhosis (27%) (p = 0.001). Category I nodules were significantly larger than category II nodules in patients with micronodular cirrhosis (p < 0.001). The doubling times of category I nodules had no statistical difference between patients with micronodular or macronodular cirrhosis (p = 0.954). Of the category I nodules in patients with micronodular cirrhosis, 8.6% showed malignant changes. CONCLUSION. More careful attention should be paid to large nodules in patients with micronodular cirrhosis because of the potentially greater risk of malignancy, and small hypoattenuating nodules should be more often followed up in shorter intervals than large nodules.