Small hepatocellular carcinoma in patients with chronic liver damage: Prospective comparison of detection with dynamic MR imaging and helical CT of the whole liver

PURPOSE: To compare contrast material-enhanced dynamic magnetic resonance (MR) imaging with helical computed tomography (CT) for the detection of small hepatocellular carcinoma (HCC) in patients with chronic liver damage. MATERIALS AND METHODS: Fifty patients with chronic hepatitis or liver cirrhosis underwent dynamic contrast-enhanced fast low-angle shot MR imaging and multiple-phase helical CT. Arterial, portal-venous, and delayed-phase images were compared. Diagnostic ability with both techniques was evaluated by means of receiver operating characteristic (ROC) analysis; images in patients with (n = 27) and those without (n = 15) HCC in whom the same anatomic levels were available for both examinations were assessed. Seventy-two lesions were evaluated, and tumor diameter ranged from 0.5 to 3.0 cm (mean, 1.9 cm). RESULTS: ROC analysis showed that the arterial-phase images obtained with both techniques allowed better detection of HCC. Diagnostic ability was significantly better with arterial-phase MR imaging (mean area under the ROC curve [Az] = 0.96) than arterial-phase CT (Az = 0.87) or with images from any other phase (P < .05). For the delayed phase, diagnostic capability was significantly better with CT (Az = 0.84) than with MR imaging (Az = 0.77) (P < .05). CONCLUSION: Arterial-phase dynamic MR imaging is superior to helical CT for the detection of HCC in patients with chronic liver damage.