Gadoxetic acid disodium‐enhanced hepatocyte phase MRI: Can increasing the flip angle improve focal liver lesion detection?

Purpose: To determine whether hepatocyte phase gadoxetic acid disodium (EOB)‐enhanced MRI using a high flip angle (FA) improves focal liver lesion (FLL) detection compared with using a standard low FA. Materials and Methods: Sixty‐two consecutive patients with 159 FLLs underwent EOB‐enhanced MRI during the hepatocyte phase at 5, 10, 15, and 20 min, with both low (10°) and high (30°) FAs. Two blinded radiologists independently and randomly reviewed the two image sets using a four‐point rating scale. Sensitivities and specificities were calculated and lesion‐to‐liver contrast ratio (LLC) on all hepatocyte phase images was measured. Results: The sensitivities with high FA for small (≤10 mm) malignant FLLs were significantly higher than those with low FA, at all time points, for both readers ( P ≤ 0.05). Meanwhile, the specificities of the two protocols for the detection of all FLLs at all time points during the hepatocyte phase were high and same (98.2%) for both readers, without any significant differences ( P = 1.00). LLCs with high FA were significantly higher than those with low FA at all time points ( P ≤ 0.001). Conclusion: Hepatocyte phase EOB‐enhanced MRI with increasing FA can significantly increase LLC and improve the detection of FLLs, particularly small malignant lesions. J. Magn. Reson. Imaging 2012;35:132‐139. © 2011 Wiley Periodicals, Inc.