Ramsey Khair Kilani MD, Presenter: Medical Advisor, FrontRad Technologies

Nicholas Thomas Befera MD, Abstract Co-Author: Nothing to Disclose

Matthew Preston Lungren MD, Abstract Co-Author: Nothing to Disclose

Ben Eugene Paxton MD, Abstract Co-Author: Nothing to Disclose

Sin-Ho Jung PhD, Abstract Co-Author: Nothing to Disclose

James David Eastwood MD, Abstract Co-Author: Nothing to Disclose

To determine if ownership of MRI equipment by ordering physicians predicts the likelihood and/or distribution of positive findings on knee MRIs, and to evaluate knee MRI pathology rates as a metric of similarity between two patient groups.

A retrospective review was performed of 989 consecutive diagnostic knee MRIs ordered over a 6 month period by two separate referring orthopedic groups serving the same geographic community; the first had financial interest in the MRI imaging equipment used (FI group), the second had no financial interest in the MRI imaging equipment used (NFI group). All studies were performed with identical protocols and interpreted by one musculoskeletal radiology group with no financial interest in imaging equipment. Final reports were reviewed and examinations with one or more of the following findings were considered positive: ACL tear, meniscal tear, MCL injury, LCL injury, patellofemoral extensor mechanism injury, full thickness cartilage defect. The relative frequency of each lesion was calculated among the positive studies in each group, and the percentage of negative examinations was tabulated for both groups.

A total of 952 patients contributed 989 scans (516 in FI and 473 in NFI) that met inclusion criteria during the study period.  Among these, 310 were negative (187 in FI, and 123 in NFI); there was a 52% increase in negative scan rate in the FI group compared to NFI(p=0.0006). Among the positive scans, there was no statistically significant difference in the average total number of positive lesions per scan,1.44 for FI and 1.57 for NFI (p=0.5625), or in the frequency of 6 out of 7 individual lesions (representing over 95% of the total lesions).

Knee MRIs referred by physicians with a financial interest in the imaging equipment used had a statistically significant 52% increase in negative scan rate over those referred by physicians with no financial incentive. Among the positive studies, there was no statistically significant difference between the two groups in total number of lesions per scan, or the frequency of 6 out of 7 individual lesions, suggesting highly similar distribution and severity of disease between the two patient samples.

Financial interest in imaging equipment may have an impact on the imaging referral patterns of ordering physicians; imaging findings may serve as metric of comparative and appropriate utilization

Kilani, R, Befera, N, Lungren, M, Paxton, B, Jung, S, Eastwood, J, To Knee or Not to Knee? A Case Study in Physician Self-referral of Knee MRI with Comparative Analysis of Lesion Rates as a Marker of Utilization Appropriateness.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11012005.html