OBJECTIVE: The objective was to evaluate the usefulness of T1 mapping in distinguishing hepatic hemangiomas from metastatic tumors on gadoxetic-acid-enhanced magnetic resonance imaging. METHODS: We examined 20 hemangiomas in 14 patients and 21 metastatic tumors in 11 patients. We performed T1 mapping using the double-flip angle method before and after the injection of gadoxetic acid. Quantitative evaluation was carried out using the pre- and post-contrast enhancement ratios (CERs), and qualitative evaluation was conducted to evaluate the added value of T1 mapping using receiver operating characteristics analysis. RESULTS: The mean CERs of metastatic tumors at 70 s, 240 s and 20 min after the injection of gadoxetic acid were 1.54 (95% confidence interval: 1.37-1.71), 1.47 (1.34-1.6) and 1.30 (1.19-1.41); those of hemangiomas were 3.36 (2.41-4.31), 3.06 (2.44-3.68) and 2.20 (2.02-2.38), respectively. The mean CERs of hemangiomas were significantly higher than those of metastatic tumors (P<.05). When the mean CER cutoff value 20 min after the injection was set at 1.6, the diagnostic sensitivity of hepatic hemangiomas was 100%. There was no added value observed statistically in the qualitative evaluation of T1 mapping (P>.05). CONCLUSION: It is valuable to evaluate quantitatively T1 mapping 20 min after hepatobiliary phase acquisition in the case of difficulty in distinguishing hepatic hemangiomas from metastatic tumors qualitatively.
OBJECTIVE: The objective was to evaluate the usefulness of T1 mapping in distinguishing hepatic hemangiomas from metastatic tumors on gadoxetic-acid-enhanced magnetic resonance imaging. METHODS: We examined 20 hemangiomas in 14 patients and 21 metastatic tumors in 11 patients. We performed T1 mapping using the double-flip angle method before and after the injection of gadoxetic acid. Quantitative evaluation was carried out using the pre- and post-contrast enhancement ratios (CERs), and qualitative evaluation was conducted to evaluate the added value of T1 mapping using receiver operating characteristics analysis. RESULTS: The mean CERs of metastatic tumors at 70 s, 240 s and 20 min after the injection of gadoxetic acid were 1.54 (95% confidence interval: 1.37-1.71), 1.47 (1.34-1.6) and 1.30 (1.19-1.41); those of hemangiomas were 3.36 (2.41-4.31), 3.06 (2.44-3.68) and 2.20 (2.02-2.38), respectively. The mean CERs of hemangiomas were significantly higher than those of metastatic tumors (P<.05). When the mean CER cutoff value 20 min after the injection was set at 1.6, the diagnostic sensitivity of hepatic hemangiomas was 100%. There was no added value observed statistically in the qualitative evaluation of T1 mapping (P>.05). CONCLUSION: It is valuable to evaluate quantitatively T1 mapping 20 min after hepatobiliary phase acquisition in the case of difficulty in distinguishing hepatic hemangiomas from metastatic tumors qualitatively.