MERRITT ISLAND, Florida—Adding magnetic resonance (MR) arthrography, which requires injecting contrast medium into the joint, would change treatment decisions in only 18% of cases compared to treatment based on noninvasive three-Tesla (3-T) magnetic resonance imaging alone. Use of both imaging methods should probably be reserved for a specific subset of patients, according to a study in the January issue of the American Journal of Roentgenology.¹

“On the basis of these findings, we perform 3-T MR arthrography on patients for whom anterior labral tears, SLAP tears, and partial-thickness supraspinatus tendon tears are suspected clinically,” said study author Thomas Magee, MD, a radiologist at Neuroskeletal Imaging in Merritt Island, Florida.

Dr. Magee said that 3-T MR arthrograms allow surgeons to identify additional lesions prior to surgery, which helps develop a better road map for surgeons.

Shoulder pain study compared arthrography vs conventional MRI

The study was based on retrospective review of 150 consecutive conventional shoulder MRI and MR arthrography examinations performed on patients who subsequently underwent arthroscopy.

“With MR arthrography we were able to see things with a high degree of accuracy in the shoulder,” said Dr. Magee. “Resolution and picture quality using 3T MRI is high in the shoulder, except for lesions that are hidden without distention of the joint [but] during MR arthrography, the distention of the joint allowed us to uncover lesions that could not be seen on conventional MRI,” he said.

The sensitivity on conventional MRI for anterior labral tears was 83%. It was 84% for posterior labral tears, 83% for SLAP tears, 92% for supraspinatus tendon tears, and 68% for partial-thickness articular surface tears. Sensitivity on MR arthrography was significantly higher, the study showed. The sensitivity for anterior labral tears on MR arthrography was 98%. It was 95% for posterior labral tears, 98% for SLAP tears, 100% for supraspinatus tendon tears, and 97% for partial-thickness articular surface tears.

Dr. Magee reported, “Overall MR arthrography altered management in 27 of 150 patients in this study. Additional findings on MR arthrography compared with conventional MRI requiring surgical intervention included three full-thickness supraspinatus tendon tears, nine partial-thickness supraspinatus tendon tears, seven SLAP tears, six anterior labral tears, and two posterior labral tears seen on MR arthrography but not on conventional MRI. On discussion with the surgeons, these patients would have been treated conservatively (no surgery) on the basis of normal results of conventional MRI.

Reference

1. Magee T. 3-T MRI of the Shoulder: Is MR Arthrography Necessary? AJR; 2009;192:86-92.