Comparison of gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced MRI and contrast-enhanced CT evaluation of liver tumors: A prospective study

Purpose This prospective study aimed to evaluate the outcomes of hepatic lesions detected by contrast-enhanced computed tomography (CE-CT) and gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (Gd-EOB-MRI), including the incidence of false-positive lesions. We also examined the characteristics of equivocal lesions. Methods In each patient undergoing hepatectomy for a liver tumor, two radiologists (readers A and B) assessed CE-CT and Gd-EOB-MRI. Hepatic lesions were scored as 1, 2, 3, 4, or 5, which corresponded to categorization as benign, probably benign, equivocal, probably malignant, or malignant, respectively. Those scored as 1 or 2 were defined as benign and those scored as 4 or 5 were defined as malignant. The lesions left unresected were confirmed as benign when they remained unchanged for ≥ 1 year after hepatectomy. The false-positive rate was defined as the number of lesions finally confirmed as benign among those assessed as malignant before surgery. Results Among the 105 enrolled patients (colorectal liver metastases, 72; hepatocellular carcinoma, 29; other, 4), 886 lesions were recognized on either CT or MRI before surgery; another 26 lesions were identified only on intraoperative ultrasonography or pathologic examination of the surgical specimen. The sensitivity of malignant lesion detection was significantly higher for Gd-EOB-MRI than CE-CT for both reader A (90.3% vs. 68.3%; P < 0.001) and reader B (88.1% vs. 70.2%; P < 0.001). The false-positive rate with CE-CT and Gd-EOB-MRI was 2.3% and 3.7%, respectively, for reader A (P = 0.580), and 0.5% and 4.2%, respectively, for reader B (P = 0.033). The size of false-positive lesions was comparable with that of correctly diagnosed malignant lesions except in reader B’s Gd-EOB-MRI evaluation (false-positive vs. correct; median, 7 mm vs. 13 mm; P = 0.015) Conclusion Gd-EOB-MRI was superior to CE-CT for detecting liver lesions. The false-positive rate was low for both modalities.