Hypointense hepatocellular nodules on hepatobiliary phase of Gd-EOB-DTPA-enhanced MRI: can increasing the flip angle improve conspicuity of lesions?

Purpose: To compare the conspicuity of hypointense hepatocellular nodules in patients with chronic liver disease on hepatobiliary phase (HP) of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) acquired with low to high flip angles (FAs).

Materials And Methods: A total of 95 patients with chronic liver disease who underwent Gd-EOB-DTPA-enhanced MRI were included. HP images were obtained at 20 minutes, with 15°, 20°, and 30° FAs. For the detected hepatocellular nodule, liver-to-lesion contrast-to-phantom ratios (CPR) and lesion conspicuity (LCS) were assessed.

Results: In all examinations, 96 hepatocellular nodules showing hypointensity on HP were identified. These lesions included 39 hypovascular nodules and 57 hypervascular nodules. Mean CPR and LCS showed the highest value on the 30° FA, followed by 20° and 15° FAs. CPR and LCS of 15° FA were significantly lower than those of 20° and 30° FAs (P < 0.001 to P = 0.007). CPR of 30° FA for hypervascular nodules was significantly greater than that of 20° FA (P < 0.001).

Conclusion: In the evaluation of hypointense hepatocellular nodules on HP of Gd-EOB-DTPA-enhanced MRI, higher FA such as 30° should be used rather than low FA such as 15°.