Hepatic MR imaging using ferumoxides: Prospective evaluation with surgicaland intraoperative sonographic confirmation in 25 cases

OBJECTIVE. The purpose of our study was to evaluate the sensitivity and acc uracy of ferumoxides-enhanced MR imaging in comparison with surgery and int raoperative sonography. SUBJECTS AND METHODS. We prospectively evaluated 25 consecutive studies in 24 patients who underwent ferumoxides-enhanced hepatic MR imaging before su rgery and intraoperative sonography. Both 1.5-T scanners (13 cases) and 0.2 -T scanners (12 cases) were used. Turbo spin-echo T2-weighted sequences wer e performed before and after the administration of ferumoxides and the imag es were compared. Lesions were classified as solid or nonsolid and tabulate d on standard liver maps. The Ever maps from MR ima-mia were compared with those from surgery and intraoperative sonography. For lesions greater than 1 cm, the regions of interest were measured and contrast-to-noise ratio was calculated. RESULTS. Of 93 solid lesions found at surgery, 69 were seen on unenhanced M R imaging (sensitivity, 74.2%) and 87 were seen on ferumoxides-enhanced MR imaging (sensitivity, 93.5%) (p < 0.05). Of the seven benign lesions (five cysts, two hemangiomas) found at surgery, all were correctly identified as benign on MR imaging. Two lesions identified as solid before surgery were n ot found at surgery. Mean lesion contrast-to-noise ratio for the unenhanced scans was 22.9 and 34.5 (p < 0.001) for the ferumoxides-enhanced scans. Su banalysis of 1.5- and 0.2-T MR imaging revealed similar results with signif icant (p < 0.05) increases in sensitivity for both. The average size of the lesions missed before surgery was 0.7 cm. CONCLUSION. Turbo spin-echo T2-weighted ferumoxides-enhanced MR imaging at either 1.5 or 0.2 T has value in preoperative liver assessment.