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 compare the diagnostic accuracy of hepatic lesions between contrast-enhanced computed tomography (CE-CT) and gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (Gd-EOB-MRI). We also examined the final diagnosis of equivocal lesions.

METHODS

In each patient undergoing hepatectomy for liver tumors, 2 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 1/2 and 4/5 were defined as benign and malignant, respectively. 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 preoperatively.

RESULTS

Among 105 enrolled patients (colorectal liver metastases, 72; hepatocellular carcinoma, 29; other, 4), 886 lesions were recognized on either CT or MRI preoperatively; another 26 lesions were identified only on intraoperative ultrasonography or pathologic examination. 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). There were 142 lesions judged as equivocal in at least one of the imaging studies by either reader. Sixty-eight lesions (49%) were recognized as malignant by any of the alternative assessments; among these, 61were confirmed as malignant.

CONCLUSION

Gd-EOB-MRI was superior to CE-CT for detecting liver lesions. The false-positive rate was low for both modalities. Equivocal lesions were encountered frequently, but routine use of alternate modalities and evaluation by 2 or more radiologists could enhance the accuracy of diagnosis.