Direkte MR-Arthrographie des Schultergelenks mit maximaler Kapseldistension zur OP-Planung

Are radiologists superior to orthopaedic surgeons in diagnosing instability-related shoulder lesions on magnetic resonance arthrography? A multicenter reproducibility and accuracy study

BACKGROUND

We compared the diagnostic reproducibility and accuracy of musculoskeletal radiologists with orthopaedic shoulder surgeons in 2 large medical centers in assessing magnetic resonance arthrograms (MRAs) of patients with traumatic anterior shoulder instability.

METHODS

Forty-five surgically confirmed MRAs were assessed by 4 radiologists, 4 orthopaedic surgeons, 2 radiologic teams, and 2 orthopaedic teams. During MRA assessment and surgery, the same 7-lesion scoring form was used. κ Coefficients, sensitivity, specificity, and differences in percentage of agreement or correct diagnosis (P < .05, McNemar test) were calculated per lesion and overall per the 7 lesion types.

RESULTS

The overall κ between the individual radiologists (κ = 0.51, κ = 0.46) and orthopaedic surgeons (κ = 0.46, κ = 0.41) was moderate. Although the overall percentage of agreement between the radiologists was slightly higher than that between the orthopaedic surgeons in both centers (80.0% vs 77.5% and 75.2% vs 73.7%), there was no significant difference. In each medical center, however, the most experienced orthopaedic surgeon was exceedingly more accurate than both radiologists per the 7 lesion types (81.9% vs 72.4%/74.6% and 76.5% vs 67.3%/73.7%). In 3 of 4 cases, this difference was significant. Overall accuracy improvement through consensus assessment was merely established for the weakest member of each team.

CONCLUSION

Experienced orthopaedic surgeons are more accurate than radiologists in assessing traumatic anterior shoulder instability-related lesions on MRA. In case of diagnosis disagreement, these orthopaedic surgeons should base their treatment decision on their own MRA interpretation.

MR arthrography of traumatic anterior shoulder lesions showed modest reproducibility and accuracy when evaluated under clinical circumstances

INTRODUCTION

We examined the reproducibility and accuracy of high-field MRA in traumatic anterior shoulder instability under conditions resembling clinical practice and assessed the influence of observer experience.

MATERIALS AND METHODS

Two radiologists with different experience levels evaluated 61 MRAs. Assessment was independent, blinded and non-sequential. For 40 MRAs, surgical reports were available to assess diagnosis accuracy and influence of observer experience. The assessed lesions were cuff lesions, Hill-Sachs lesions, bony and classic Bankart lesions, greater humeral tuberosity fractures, SLAP lesions and joint capsule lesions. Reproducibility was quantified using kappa coefficients. Accuracy was evaluated with sensitivity and specificity rates, positive and negative predictive values. Differences in the percentage of correctly diagnosed MRAs between the radiologists were tested using McNemar's test for paired proportions.

RESULTS

Inter-observer k-values ranged from 0.03 for joint capsule lesions to 0.45 for humeral head lesions. The overall kappa was 0.21 (95% CI; 0.12-0.30). We also observed markedly lower sensitivity and specificity rates than those reported in the literature for most lesions. The more experienced radiologist correctly diagnosed 78.9% of all lesions compared to 65.4% for the less experienced radiologist (P < 0.001; McNemar's test).

CONCLUSION

MRA-interpretations of traumatic anterior shoulder instability should be regarded with caution in clinical practice. The experience level of radiologists can affect reproducibility and accuracy.

3T MR Imaging of the Musculoskeletal System (Part II): Clinical Applications

The gain in SNR that is afforded by 3T MR imaging systems has tremendous clinical applications in the musculoskeletal system. The potential for demonstrating and enhancing the visibility of normal osseous, tendinous, cartilaginous, and ligamentous structures is exciting. Furthermore, harnessing this added signal to increase spatial resolution may improve our diagnostic abilities in various joints dramatically. Radiologists have enjoyed great success in assessing joint disease with current MR imaging field strengths; however, many intrinsic joint structures remain poorly evaluated, which leads to a golden opportunity for 3T MR imaging. The articular cartilage of the knee, the glenoid labrum of the shoulder, the intrinsic ligaments and TFC of the wrist, the collateral ligaments of the elbow, the labrum and articular cartilage of the hip, and the collateral ligaments of the ankle have been evaluated suboptimally on 1 .5T systems using routine nonarthrographic MR images. Because of the enhanced SNR, the higher spatial resolution, and the greater CNR of intrinsic joint structures at higher field strengths, 3T MR imaging has the potential to improve diagnostic abilities in the musculoskeletal system vastly, which translates into better patient care and management. The author's 2 years of clinical experience with musculoskeletal MR imaging on 3T systems has met and exceeded his expectations, and has bolstered the confidence of his orthopedic surgeons in his diagnoses. As coil technology advances and as the use of parallel imaging becomes more available in the extremities, the author expects to see even more dramatic improvements in image quality.