MR diagnosis of superior labral anterior posterior (SLAP) injuries of the glenoid labrum: value of routine imaging without intraarticular injection of contrast material.

OBJECTIVE: Superior labral anterior posterior (SLAP) lesions are peculiar types of tears that involve the superior and anterior aspects of the glenoid labrum and extend posteriorly. The biceps tendon may also be involved in the injury. There have been conflicting reports in the literature about the value of MR imaging in depicting these injuries. Some authors have advocated imaging in special planes and, more recently, the use of intraarticular injection of contrast material to facilitate the diagnosis of SLAP injuries. Symptoms of SLAP injury of the glenoid labrum are nonspecific, and patients are often imaged according to routine imaging protocols that include images in axial, oblique coronal, and oblique sagittal planes using spin-echo pulse sequences. Intraarticular injection of contrast material is not part of routine MR imaging of the shoulder. We sought to determine the value of routine MR imaging without intraarticular contrast enhancement in the diagnosis of SLAP injuries of the glenoid labrum.

MATERIALS AND METHODS: The MR images of eight patients with arthroscopically proved SLAP lesions were selected for this study. The MR imaging appearance of the glenoid labrum, biceps tendon attachment, and rotator cuff tendons were retrospectively evaluated in the axial, oblique coronal, and oblique sagittal planes in each case. The findings were correlated with the surgical observations.

RESULTS: All eight patients showed an abnormal labrum on the coronal MR images, on 88% of the axial images, and on 50% of the sagittal images. An oblique or horizontal linear focus of increased signal was seen to traverse the labrum in 50% of the cases on sagittal images. Fifty percent of the cases also showed an intraarticular body, presumably representing the displaced fragment of a bucket-handle tear, on all imaging planes (the MR "Cheerio" sign).

CONCLUSION: Routine MR imaging of the shoulder without intraarticular injection of contrast material is useful in the diagnosis of SLAP injuries of the glenoid labrum.