Is a single direct MR arthrography series in ABER position as accurate in detecting anteroinferior labroligamentous lesions as conventional MR arthography?

Abstract

Purpose The purpose of this study is to retrospectively compare accuracy of single magnetic resonance (MR) arthrography series in Abduction External Rotation (ABER) with conventional MR arthrography for detection and characterisation of anteroinferior labroligamentous lesions, with arthroscopy as reference standard. Interobserver variability of both protocols was determined. Methods and materials Institutional review board approval was obtained; informed consent was waived. MR arthrograms, including oblique axial fat suppressed T1-weighted images in ABER position and conventional imaging directions of 250 patients (170 men, 80 women; mean age, 36 years), were retrospectively and independently evaluated by three reviewers. Reviewers were blinded to clinical information and arthroscopic results. Labroligamentous lesions were registered in both ABER and MRa. The lesions were sub-classified (Bankart, Perthes, anterior labrum periosteal sleeve avulsion (ALPSA) or lesions not otherwise specified). Inter-observer agreement was assessed by Kappa statistics for all 250 patients. Ninety-two of 250 patients underwent arthroscopy. Sensitivity, specificity and accuracy of ABER versus conventional MR arthrography were calculated and compared using paired McNemar test.Results Kappa values of the ABER and conventional MR arthrography ranged from 0.44 to 0.56 and 0.44 to 0.62, respectively. According to arthroscopy, 45 of 92 patients had an intact anteroinferior labrum, and in 44 patients, a labroligamentous lesion (eight Bankart, seven Perthes, 29 ALPSA and three lesions not otherwise specified) was diagnosed. There were no statistically significant differences between ABER and conventional MR arthrography regarding sensitivity (85-89%, 89-96%), specificity (82-91%, 84-89%) and overall accuracy (50-62%, 53-63%). Conclusion The results of a single MR arthrography series in ABER position are comparable with those of conventional MR arthrography for detecting anteroinferior labroligamentous lesions.

A meta-analysis of the diagnostic test accuracy of MRA and MRI for the detection of glenoid labral injury

“…Given these indications of greater diagnostic accuracy, further study is therefore warranted to investigate the appropriateness of using higher field strength machines in the assessment of patients with suspected labral lesions. Six studies assessed the diagnostic test accuracy of MRI or MRA in abduction and external rotation shoulder positions (ABER) [21,24,[31][32][33][34]. It has been hypothesised that by positioning the patient's shoulder in this position, the anterior band of the inferior glenohumeral ligament is then placed under greater tension so that the anterior glenoid labrum is then distracted which optimises the penetration of contrast material into a tear [31].…”

Functional outcome and the structural integrity of arthroscopic Bankart repair: a prospective trial

“…Previous studies have demonstrated that ABER has equal, if not better, sensitivity and specificity compared to standard MR arthrogram views for detecting anterior inferior labroligamentous lesions. 23 Hence, our findings indicate once more that reestablishment on MR arthrogram at 6 months postoperatively may not correlate with functional outcomes.…”

Assessment of paired binary data

“…A typical example is presented in [16]. From the comparison of an imaging method (conventional magnetic resonance, MR) in n = 92 patients to the gold standard (arthroscopy, AR) in detection of supraspinatus tendon tears, the numbers in Table 1 resulted.…”

“…The main scientific question in [16] was to evaluate sensitivity and specificity of MR and a second experimental method, abduction external rotation (ABER), see Table 3 for the corresponding number of patients. The two experimental methods, MR and ABER, differ in the positioning of the patient's arm.…”

“…images or patients (see e.g. [6,9,16]). In general, "paired", "correlated", or "clustered" binary data does not only arise when comparing two different methods on the same experimental units, but also when measuring a binary response twice, e.g.…”