New MRI techniques may help patients avoid knee surgery

Patients with suspected meniscal tears or other injuries to their knees may be able to avoid arthroscopic surgery by having a 3-Tesla MRI examination instead, two studies together indicate.

Researchers compared 3-Tesla MRI (a newer version of standard MRI) to arthroscopy and found that 3-Tesla MRI had an accuracy rate of 96% in detecting meniscal tears. The MRI examinations were able to identify 108 of the 112 meniscal tears that were found when arthroscopic surgery was performed, said Tom Magee, MD, from Neuroskeletal Imaging in Merritt Island, FL, and the lead author of both studies. There were three cases in which the MRI demonstrated a meniscal tear, not seen on arthroscopy, Dr. Magee noted. “Because 3-Tesla MRI is accurate, we can confidently examine patients with suspected meniscal tears to determine if they need surgery immediately or if they might benefit from rehabilitation first to see if their knee injury heals, possibly avoiding surgery altogether,” Dr. Magee said.

3-Tesla MRI can be performed in a unique way (called isotropic imaging) so that the knee can be seen from all angles and planes then reconstructed three dimensionally as a “virtual arthroscopy.” This shows promise not only in detecting meniscal tears, but ACL tears, MCL injuries and chondral knee injuries as well, Dr. Magee said. “We compared this new technique to conventional MR knee imaging, and found that both are equally accurate. The benefit to the new technique is that it can be done faster with less patient motion,” Dr. Magee said. In addition, the new technique shows promise in better characterizing meniscal tears as stable or unstable. “If a tear is stable, the patient may not need surgery; an unstable tear (the tear can be moved during surgery) requires surgery sooner rather than later,” he said. Dr. Magee cautions that MR isotropic imaging is new and isn’t quite ready to replace standard MR knee imaging. However, he is hopeful it could eventually supersede current knee imaging techniques.

Meniscal tears and other knee injuries are commonly seen in all types of patients, Dr. Magee said.

The study was presented at the American Roentgen Ray Society Annual Meeting in New Orleans, LA.

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