COST-EFFECTIVENESS OF UNENHANCED MR-IMAGING VS CONTRAST-ENHANCED CT OF THE ABDOMEN OR PELVIS

OBJECTIVE. The purpose of this study was to compare the cost of unenha nced MR imaging with that of CT with high- or low-osmolality contrast agents for abdominal or pelvic imaging in patients at risk for nephrot oxic effects induced by contrast material. MATERIALS AND METHODS. Usin g decision analysis, we evaluated direct medical care costs associated with the use of CT with high- or low-osmolality contrast agents vs MR imaging. We used data from a variety of sources and assumed that the three imaging techniques provide nearly equivalent diagnostic informat ion. The base-case analysis assumed that patients were at low risk (i. e., 2%) for development of nephrotoxic effects. Nephrotoxic effects we re defined as increases in the serum level of creatinine of 50% or mor e above baseline. Our analysis took the perspective of the hospital an d used estimated hospital costs, not charges. Sensitivity analyses wer e performed on risk estimates for development of nephrotoxic effects a nd for the estimates of medical care costs. RESULTS. For the base case , CT with a high-osmolality contrast agent is the least costly imaging strategy. When the risk of nephrotoxic effects exceeds 5% for high-os molality contrast agents or 2.6% for low-osmolality contrast agents, t hen MR imaging is the preferred strategy, The model is relatively inse nsitive to treatment costs. CONCLUSION. From a hospital's perspective, MR imaging of the abdomen or pelvis is cost minimizing in patients at high risk for nephrotoxic effects induced by contrast agents. Use of tow-osmolality contrast agents must reduce the frequency of nephrotoxi c effects in high-risk patients by at least 50% to be less costly than MR imaging.