Liver metastasis detection: comparative sensitivities of MR imaging and CT scanning

Twenty patients with known liver metastases were evaluated by unenhanced computed tomography (CT), scans enhanced with ethiodized oil emulsion-13 (EOE-13), and magnetic resonance (MR) imaging with three pulse sequences. Spin-echo (SE) 300/26 (repetition time/echo time, in msec) images prospectively demonstrated 95.4% of the detectable liver metastases; inversion recovery (IR) 1,500/100 (repetition time/inversion time, in msec) images revealed 90.8%; and EOE-13-enhanced CT scans showed 87.1%. SE 2,000/80 images showed 51.4%, and unenhanced CT scans 49.6%, of the metastases. The relationship of vascular anatomy to metastatic foci was best seen on SE 300/26 images and EOE-CT scans. SE 300/26, IR 1,500/100, and EOE-CT studies particularly improved detection of lesions in the 1-2-cm range compared with SE 2,000/80 imaging or unenhanced CT scanning. SE 300/26 and IR 1,500/100 sequences appear comparable to EOE-CT scans in demonstrating liver metastases and significantly superior to conventional CT scans. Because EOE-13 is generally not available, these MR sequences should be the procedure of choice for the diagnosis of liver metastases.