Hepatic tumor imaging using iron oxide MRI: comparison with computed tomography, clinical impact, and cost analysis

The surgical management of hepatic tumors has traditionally relied on preoperative contrast-enhanced computed tomography (CECT) in combination with intraoperative ultrasonography (IOUS). Unfortunately, the ability to detect and characterize hepatic tumors by using CECT is limited, and IOUS frequently reveals additional disease that alters the operative approach. Recent advances in hepatic magnetic resonance imaging (MRI) may improve preoperative tumor detection and characterization; however, little is known about how MRI compares with CECT or about the clinical impact and cost considerations of liver MRI.

A retrospective chart review was performed to compare iron oxide (Feridex [Fe])-MRI with CECT in the preoperative imaging of hepatic neoplasms, as well as to determine the clinical impact and overall healthcare costs associated with Fe-MRI.

Of approximately 1000 patients who underwent abdominal MRI at a single institution during a 20-month period, 57 were identified who underwent Fe-MRI evaluation of the liver. Indications for imaging included suspected metastases (n = 43), an indeterminate hepatic mass (n = 9), or primary hepatic cancer (n = 5). Overall, Fe-MRI identified a total of 157 lesions (mean, 2.75 per patient; range, 0-14). CECT was performed in 50 patients, of whom 35 had primary or metastatic cancer. Fe-MRI identified more lesions than CT (n = 136 vs. 77; P = .016), and the average size of lesion detected by Fe-MRI was significantly smaller than that by CECT (2.5 vs. 3.4 cm; P = .018). Comparison of CECT and Fe-MRI findings with IOUS and pathological specimens showed a significant difference in sensitivity (MRI, 86%; CECT, 58%; P<.001), and IOUS changed the operative approach in only 5% of those imaged with Fe-MRI. Overall, Fe-MRI altered the clinical management in 67% of patients imaged (n = 38 of 57), which corresponded to an overall net cost savings of $108,368 ($1,901 per patient).

Fe-MRI is a powerful imaging technique, with greater hepatic tumor detection sensitivity than CECT. Moreover, it is an economically feasible imaging method that will alter the clinical management in most patients imaged.