ABSTRACT
PURPOSE: To assess whether ring enhancements of liver metastases on Mn-DPDP enhanced, early MR images were well visualized on delayed images, as compared with those of hepatocellular carcinomas (HCC), and to investigate the detection accuracy and conspicuity of each tumor. MATERIALS AND METHODS: Twenty patients with liver metastases and 15 with HCC were studied by Mn-DPDP enhanced, T1-weighted MR images. Peripheral ring enhancement and conspicuity were investigated. Differences in detection accuracy and frequency of ring enhancement in liver metastases and HCC were assessed. RESULTS: In liver metastases (n=69), 44 cases (63.8%) without ring enhancement and 25 (36.2%) with were noted on early images. Sixteen cases (23.2%) without ring enhancement, 38 (55.1%) with ring enhancement similar to the early images, and 15 (21.7%) with prominent ring enhancement were noted on delayed images. In HCC (n=37), 36 cases (97.3%) without ring enhancement and 1 case (2.7%) with were noted on early images. There was no difference of detection accuracy in liver metastases or HCC between the 2 readings. Ring enhancement and conspicuity of each tumor were superior on delayed images. Ring enhancement in liver metastases was better seen on delayed images. CONCLUSION: Ring enhancement in liver metastases was well presented on Mn-DPDP enhanced, delayed MR images, which was useful to differentiate liver metastases from HCC.