Gd-EOB-DTPA-enhanced 3.0 T MR imaging: quantitative and qualitative comparison of hepatocyte-phase images obtained 10 min and 20 min after injection for the detection of liver metastases from colorectal carcinoma.

Abstract

To compare quantitatively and qualitatively hepatocyte-phase images obtained 10 and 20 min (Images-10, and Images-20) after injection of gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA) to detect liver metastases from colorectal carcinoma on 3.0 T MR imaging. A total of 48 patients (26 men, 22 women; mean age, 64 years) with 88 histopathologically confirmed liver metastases underwent Gd-EOB-DTPA-enhanced MR imaging. Tumour-to-liver contrast-to-noise ratio (CNR), signal intensity gain (SIG) of liver parenchyma and overall image quality were analysed. Two radiologists independently reviewed two sets of MR images: set 1, unenhanced (T1- and T2-weighted), dynamic images and Images-10; set 2, unenhanced, dynamic and Images-20. Sensitivity and positive predictive value (PPV) to detect liver metastases, and diagnostic performance using the alternative free-response receiver operating characteristics (AFROC) method were calculated. The mean tumour-to-liver CNR, SIG of liver parenchyma and overall image quality on Images-20 were significantly higher than those on Images-10. The overall image quality of "fair to excellent" was achieved on both images in 93.8% of the patients. Sensitivity, PPV and area under the AFROC curve on set 1 were similar to set 2, including lesions <1 cm. In detecting liver metastases from colorectal carcinoma, Images-10 could replace Images-20 in 3.0 T MR imaging.