Indirect MR-Arthrography of the shoulder-value in the detection of SLAP-lesions

Purpose: A prospective study to assess the value of indirect magnetic resonance-arthrography (MR-Arthro) in the detection of lesions of the superior labrum (SLAP-lesions). Materials and Methods: Unenhanced magnetic resonance imaging (MRI) and indirect MR-Arthro of the shoulder were performed in 35 patients (9 females and 26 males) with a history of acute or chronic shoulder disorder. The images of unenhanced MRI and indirect MR-Arthro were analyzed independently from each other for the occurrence of SLAP-lesions and the findings correlated with the arthroscopic results. For arthroscopy, MRI and MR-Arthro, the SLAP-lesions were categorized based on the classification system of Snyder. Results: SLAP-lesions were diagnosed-by arthroscopy in 22 of 35 patients (63%). 9 of the 22 lesions (41%) were classified as type 1, 9 (41%) as type 2, three (13.5%) as type 3 and one (4.5%) as type 4. Using unenhanced. MRI sensitivity, specificity and accuracy in the detection of SLAP-lesions were calculated to be 73%, 85% and 77%. Indirect MR-Arthro showed a sensitivity of 91%, a specificity of 85% and an accuracy of 89%. Unenhanced MRI revealed correlation to the arthroscopic classification in 9 of 22 cases (41%) and indirect MR-Arthro in 18 of 22. cases (82%). Conclusion: Indirect MR-Arthro is a non-invasive method which offers excellent sensitivity in the diagnosis of SLAP-lesions. It provides important preoperative informations with regard to the exact location and extent of a tear.