Detecting hepatocellular carcinoma in gadoxetic-acid-enhanced hepatobiliary-phase MR imaging at 3T: comparing high and low flip angle

Abstract

We evaluated the diagnostic performance of fat-suppressed 3D T1-weighted gradient-echo magnetic resonance imaging (MRI) sequences for the hepatobiliary phase of gadoxetic-acid-enhanced liver MRI between low and high flip angle (FA) at 3T. Forty-six patients with 62 HCCs were enrolled in this retrospective study from among 267 consecutive patients who underwent 3T MRI with low and high FA (10° and 25°) sequences at the hepatobiliary phase. A radiologist measured signal intensities and standard deviations (SD) of lesion, liver, and spleen and calculated signal-to-noise ratio, liver-spleen contrast, and liver-lesion contrast. Two reviewers assessed both image sequences using a five-point rating scale focusing on detecting hypointense lesions. The high FA sequence showed significantly higher liver-spleen and liver-lesion contrast compared with those of low FA (p<0.05, p<0.05, respectively). Per-lesion sensitivities of high FA were higher than those of low FA (p<0.05, p<0.05, respectively), and per-person sensitivities were elevated on high FA (p<0.05 in a reviewer). There were statistically significant differences for detecting HCCs larger than 1cm (p<0.05, p<0.05, respectively). Increasing FA in T1-weighted hepatobiliary-phase liver MRI may help in detecting HCC at 3T.