COST-EFFECTIVENESS AND OUTCOME ASSESSMENT OF MAGNETIC-RESONANCE-IMAGING IN DIAGNOSING CORD COMPRESSION

Background. This study was designed to investigate the costs associate d with the use of magnetic resonance imaging (MRI) in the workup of sp inal cord compression caused by metastatic disease, an area in which i t has proven to be diagnostically useful. Methods. The study was divid ed into two parts. Part 1 consisted of a retrospective review of the h ospital charts of 46 patients, half of whom were diagnosed with cord c ompression in the pre-MRI era and the other half diagnosed after MRI a vailability; costs for these two groups were compared. Part 2 consiste d of a review of several major studies comparing the sensitivities and specificities of MRI with alternative imaging techniques, usually mye lography. Cost effectiveness and cost/cost ratios were derived for dia gnostic usefulness using prevalence, sensitivity, specificity, and cos t estimates of MRI and its alternatives, including costs of false-nega tive and false-positive testing. Results. Our hospital-based experienc e yielded an average cost of $3664 per patient without MRI and $2283 p er patient when MRI was available (1991 dollar amounts). The cost of d iagnosis was 65% more expensive without MRI. Use of the literature-bas ed experience demonstrated that the cost of diagnosis was at least 82% more costly without MRI than when it was available. However, when key variables were altered during sensitivity analysis, this difference o f increased cost of diagnosis without MRI ranged from 25% to 98%. Conc lusion. This work suggests that MRI may result in significant economic benefits in diagnosing metastatic cord compression, but further work is needed on physician behavior and referral patterns with MRI versus myelography as is long term follow-up for potential reductions in pati ent debility using MRI.