Comparison of In-Phase and Opposed-Phase FMPSPGR Images in Breath-hold T1-weighted MR Imaging of Liver

ABSTRACT

PURPOSE: To compare the effectiveness of the in-phase(IP) sequence and the opposed-phase(OP) sequence in the detection of focal hepatic lesions in the single breath-hold hepatic MR imaging with fast gradient T1-weighted pulse sequences. MATERIALS AND METHODS: If and OP T1-weighted breath-hold imaging was performed using fast gradient echo sequences in 45 patients referred for known focal hepatic lesions, in which 78 lesions were detected. There blind readers independently reviewed the images for lesion detectability. The signal-to-noise ratio(SNR) of the liver, the lesion-to-liver contrast-to-noise ratio(CNR) and the liver-to-spleen CNR were also compared. A consensus was reached by three readers to determine which sequence is better in image quality. RESULTS: On OP images, 61(78%), 61(78%), and 63(89%) lesions were correctly identified for reader 1, 2 and 3, respectively. On IP images, 66(85%), 65(83%), and 65(93%) lesions were detected for each reader, respectively. When two image sets were combined, 71(91%), 69(88%), and 76(97%) lesions respectively were detected for each reader. In cases of hepatocellular carcinoma, liver-to-lesion CNR was greater on the OP images(p<0.05), but in other lesions significant differences was not demonstrated. Liver-to-spleen CNR was higher in OP images(p<0.1), but the SNR of the liver was higher on the If images. CONCLUSION: Use of both If and OP imaging can be helpful to avoid erroneous missing of some focal hepatic lesions.