Purpose: The technique of double-phase echo chemical shift gradient-echo magnetic resonance (MR) imaging with the fast low-angle shot sequence (double-echo FLASH) provides in-phase and opposed-phase (double-phase) images simultaneously. The purpose of this study was to assess whether the dynamic study with a combination of in-phase and opposed-phase (double-phase) echo images improves the detectability of hypervascular hepatocellular carcinoma (HCC) compared with that with either in-phase or opposed-phase images alone.
Method: Thirty-seven patients with 107 hypervascular HCCs who underwent the whole-liver double-phase echo dynamic MR imaging were enrolled in the study. Three radiologists blindly read in-phase images alone, opposed-phase images alone, and then double-phase images together. Sensitivity and positive predictive values as well as the areas below the alternative-free response receiver operating characteristic curve (Az values) for each imaging technique were calculated and compared statistically.
Results: The mean sensitivity, positive predictive values, and Az values for hypervascular HCCs were 51%, 77%, and 0.52 for in-phase imaging; 55%, 86%, and 0.58 for opposed-phase imaging; and 57%, 84%, and 0.63 for double-phase imaging, respectively. The mean sensitivity for opposed-phase imaging was significantly higher than that for in-phase imaging (P < 0.05), and the mean sensitivity for double-phase imaging was higher than that for in-phase imaging (P < 0.01). The mean Az value for the double-phase imaging was significantly higher than that for in-phase imaging (P < 0.01).
Conclusion: Dynamic MR imaging with double-phase images was recommended for the detection of hypervascular HCC.