3-T MR Arthrography Statistically More Sensitive Than Routine 3-T MRI

The objective of a recent study was to determine if 3-T MR arthrography is a justifiable study to perform given the invasive and more time-consuming nature of the examination when compared with standard 3-T MRI.

The results have shown that when anterior labral tears, superior labrum anterior-to-posterior (SLAP) tears, and/or partial-thickness supraspinatus tendon tears are suspected by clinical history, 3-T MR arthrography has improved diagnostic capability compared with standard 3-T MRI.

Design/Participants
Retrospective analysis of 150 patients who were evaluated with both 3-T MRI and 3-T MR arthrography. Every patient had their findings confirmed by shoulder arthroscopy.

Methodology
Standard MRI of the shoulder used both T1- and T2-weighted sequences. MR arthrograms were performed using accepted standard techniques. Particular attention was given to evaluate the glenoid labrum and supraspinatus tendon.

Results
With particular respect to anterior labral tears, SLAP tears, and partial-thickness supraspinatus tendon tears, 3-T MR arthrography demonstrated increased diagnostic sensitivity compared with regular 3-T MRI.

Conclusions
In 18% of patients evaluated for shoulder pathology, 3-T MR arthrography altered management through increased detection of anterior labral tears, SLAP tears, and partial-thickness supraspinatus tendon tears. For patients in whom any of these entities are suspected, routine 3-T shoulder MRI is superseded in accuracy by MR arthrographic evaluation.

Reviewer’s Comments
In standard radiology practice, certain procedures can be labor-intensive and difficult for both the patient and physician. MR arthrography is a well-accepted method in evaluating shoulder anatomy; however, the advent of stronger-field magnets and enhanced image acquisition techniques may obviate the need for arthrography in certain clinical situations.

Since shoulder pain is very common, it is imperative for the radiologist to suggest the best modality in evaluating suspected pathology. Although standard MRI is quick, Magee has demonstrated that in certain instances (i.e., anterior labral tears, SLAP tears, and partial-thickness supraspinatus tendon tears), MR arthrography has improved diagnostic capability.

Given the implications for orthopedic surgeons, this study demonstrates how radiologists can help direct clinical care, in addition to being diagnosticians—something to which all radiologists should aspire, in my opinion.

Author: Rahul Pawar, MD

Reference:
Magee T. 3-T MRI of the Shoulder: Is MR Arthrography Necessary?
AJR Am J Roentgenol; 2009;192 (January): 86-92: