Magnetic resonance-guided direct shoulder arthrography for the detection of superior labrum anterior-posterior lesions using an open 1.0-T MRI scanner

Abstract

Purpose: Direct magnetic resonance arthrography (MRA) offers increased diagnostic accuracy compared to conventional magnetic resonance imaging (MRI) in the detection of superior labrum anterior-posterior (SLAP) lesions. The aim of the present study was to present the technique of magnetic resonance-guided direct shoulder arthrography (MDSA), to evaluate the diagnostic value of this novel MRA procedure to detect SLAP lesions in comparison to the currently practiced MRI, and to correlate the radiological findings to the respective arthroscopic findings.

Material and methods: Fifty-six patients with clinical signs of a SLAP lesion underwent both MRI examination and MDSA prior to arthroscopic surgery. The MRI of both interventions were compared with the arthroscopic findings. Statistical analysis was performed using the McNemar test.

Results: Sensitivity, specificity, and accuracy for detecting SLAP lesions were 23%, 88%, and 54% on MRI and 80%, 81%, and 80% on MDSA, respectively. Sensitivity (p < 0.001) and accuracy (p = 0.001) in detection of SLAP lesions were significantly higher by MDSA whereas accuracy showed no significant differences (p = 0.625).

Conclusions: The MDSA can be performed in an open 1.0-T MRI scanner with a high level of technical success and a reasonable methodical effort. The modification of MRA provides the requirements as a practicable routine shoulder magnetic resonance examination including arthrography to detect SLAP lesions. The diagnostic value is significantly better than MRI examinations without included arthrography, which currently predominates the clinical practice to investigate shoulder pathology.

Keywords: MR arthrography; SLAP lesions; conventional MRI; shoulder; shoulder arthroscopy.

Figure 1

Study group recruitment

Figure 2

The open 1.0-T MRI scanner with two parallel superconducting magnet poles. The open configuration allows a direct intra-articular injection of the contrast medium. No repositioning of the patient or changing of the receiver coil was necessary

Figure 3

Normal superior capsulolabral complex. 30-year-old male athlete with a normal superior capsulolabral complex. Coronal fat-suppressed T2-weighted conventional magnetic resonance imaging (A) and magnetic resonance arthrogram images (B) show normal low signal intensity fibrocartilage; no contrast material extends into the labrum or into the chondrolabral junction. The corresponding arthroscopic evaluation (C) shows a normal superior capsulolabral complex

Figure 4

Superior labrum anterior-posterior (SLAP) lesion type II according to the Snyder classification. 39-year-old male athlete with a SLAP II lesion. Coronal fat-suppressed T2-weighted conventional magnetic resonance imaging (A) and magnetic resonance arthrogram images (B) show a detachment with a laterally curved linear signal separating the superior labrum from the glenoid rim. The corresponding arthroscopic evaluation (C) reveals a SLAP lesion type II according to the Snyder classification