Ultrasound and preoperative MRI may be cost effective in evaluating some rotator cuff tears

Use of ultrasound as an initial imaging test for rotator cuff tears along with preoperative MRI for the identification of alternative and concurrent diagnoses is a cost-effective hybrid imaging strategy for specific cases, according to a study presented at the 2011 Annual Meeting of the American Roentgen Ray Society.

“Our research shows that in populations with a lower pre-test probability of rotator cuff tear (e.g. patients seeing family practice physicians as opposed to a shoulder specialist surgeon), it may be more cost effective to initially obtain an ultrasound,” lead study author Robert Lee Suber, MD, stated in an American Roentgen Ray Society press release. “Then, if the patient needs to have surgery, they can get an MRI.”

A decision model

Suber and his team constructed a decision model of the evaluation and treatment of rotator cuff tears, paying attention to three different strategies: ultrasound alone, MRI alone and a “hybrid strategy” of ultrasound for each patient with a subsequent MRI for those who required surgery.

The investigators used literature and expert opinions to determine outcome probabilities and effectiveness, and used Medicare reimbursements to estimate costs from a societal perspective. According to the study abstract, the team used the standard society willingness to pay of $50,000 per quality adjusted life year.

Overall, they found that ultrasound alone was the most cost-effective imaging strategy. The combined ultrasound and preoperative MRI strategy demonstrated superior cost-effectiveness when compared with MRI alone. The authors did note, however, that when the sensitivity of ultrasound for full-thickness tears fell below 89% or sensitivity for partial-thickness tears fell below 50%, MRI alone was preferred over the hybrid imaging strategy. They also found MRI alone to be preferable when the specificity of ultrasound for all rotator cuff tears fell below 60%.

When the sensitivity of MRI for full-thickness tears rose above 95% — or above 79% for partial-thickness tears — the abstract noted MRI alone was preferred more than the hybrid imaging strategy.

Limits of cost effectiveness

“One of the imaging strategies we studied was an initial screening test with ultrasound,” Suber stated in the release. “All those patients who required surgery or failed conservative treatment would then have an MRI. We found this to be more cost effective than everyone undergoing MRI as the initial evaluation.”

According to the release, there are cutoff values for accuracy of ultrasound and/or MRI where the combined imaging strategy no longer displays cost effectiveness compared with the use of MRI alone. Furthermore, as the pre-test probability for rotator cuff tear increases, the authors noted in the release that the combined imaging strategy begins to decrease in cost savings compared with MRI alone.

Reference:

Suber RL, Mather R, Orlando L. Cost utility analysis of ultrasound alone, MRI alone, and ultrasound plus preoperative MRI for the evaluation of rotator cuff tears. Paper 195. Presented at the 2011 Annual Meeting of the American Roentgen Ray Society. May 1-6. Chicago, IL.

www.acr.org

Disclosure: No relevant financial disclosures were reported.

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