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 degrees) and high (30 degrees) 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.