Computed Tomography-like Magnetic Resonance Imaging versus Multidetector Computed Tomography for the Evaluation of Shoulder Instability: Is It Comparable?

Purpose or Learning Objective: Bone defects in shoulder instability are the major cause of surgical failure, emphasizing the need for accurate presurgical assessment. The glenoid track method helps predict recurrent instability after surgery and plan treatment accordingly. Multidetector computed tomography (MDCT) arthrography is currently considered the most accurate imaging technique to quantify bone lesions. This study compared MDCT arthrography with computed tomography (CT)-like magnetic resonance imaging (MRI) arthrography in a cohort of patients presenting with glenohumeral instability and dislocation.

Methods or Background: All patients had recurrent instability and shoulder dislocation. They underwent MDCT and MRI arthrography on the same day. A total of 21 patients were enrolled. The mean patient age was 26 ± 7 years (7 women and 14 men). A standard exam was performed with an 88-row Canon MDCT and 3-T Philips, including an additional optimized three-dimensional multiecho in-phase sequence for bone damage for the assessment of CT-like bone images. A third-year radiology resident performed the measures, and the results were reviewed together with a musculoskeletal radiologist with 25 years of experience.

Results or Findings: All patients showed Hill-Sachs lesions. One of them demonstrated a reverse Hill-Sachs lesion and one a double Hill-Sachs lesion. Eight exhibited glenoid bone loss. We compared measurements obtained from both MDCT and CT-like MRI using Pearson’s correlation coefficient. The coefficient was 0.97 for the Hill-Sachs interval, 0.96 for the glenoid index, and 0.91 for the glenoid track, all of which indicate a strong positive correlation. This suggests that CT-like MRI or MDCT measurements cannot be considered superior or inferior to the other and that both provide the same information for a surgical plan. Patients who did not present a glenoid bone loss demonstrated a Bankart lesion (seven patients), anterior labrum periosteal sleeve avulsion (ALPSA) lesion (four), or a posterior labrocapsular periosteal sleeve avulsion (POLPSA) lesion (one). Only one patient demonstrated a Hill-Sachs lesion without glenoid involvement. All of these lesions could only be properly assessed in the MRI study. In our cohort, only two patients demonstrated a cartilage lesion, visible on both MRI and MDCT.

Conclusion: Although CT measures offer confidence in radiologic readings of shoulder instability, MRI measures are comparable, especially if they include CT-like sequences. MRI performs better at accurately depicting labrum lesions. Cartilage lesions were infrequent in our series, and the results were comparable.

Publication History

Article published online:
22 May 2024