Triple arterial phase dynamic MRI with sensitivity encoding for hypervascular hepatocellular carcinoma: comparison of the diagnostic accuracy among the early, middle, late, and whole triple arterial phase imaging.

OBJECTIVE: We assessed and compared the diagnostic accuracy of the early, middle, late, and whole triple arterial phase MRI with sensitivity encoding (SENSE) for the detection of hypervascular hepatocellular carcinoma (HCC).
MATERIALS AND METHODS: Thirty-one patients with 102 HCCs underwent dynamic MRI with SENSE. The findings of CT examinations, combined with those of visceral angiography or histopathologic examination, were used as the gold standard. After acquisition of T1- and T2-weighted images, gadolinium-enhanced triple arterial, portal, and delayed phase images were obtained. Acquisition of the triple arterial phase imaging was started at the timing of peak aortic enhancement and completed within a single breath-hold. Acquisition time for each phase was 8.4 sec. Four image sets including the early, middle, late, and whole triple arterial phase imaging were interpreted separately by four observers. The mean values of area under alternative-free-response receiver operating characteristic (AFROC) curve and of sensitivity were compared among the four image sets.
RESULTS: The mean values of area under AFROC curve were 0.52, 0.66, 0.53, and 0.68 and of sensitivity were 45%, 64%, 48%, and 65% for the image sets with the early, middle, late, and whole triple arterial phase imaging, respectively. Both mean values were significantly higher for the image sets with the middle and whole triple arterial phase imaging than for those with the early and late arterial phase imaging.
CONCLUSION: The middle arterial phase imaging with k-space centered at 12.6 sec after the peak aortic enhancement was optimal for detecting HCC and showed diagnostic accuracy equivalent to that of the whole triple arterial phase imaging.