Diagnostic performance of magnetic resonance arthrography of the shoulder in the evaluation of anteroinferior labrum abnormalities: a prospective study

Magnetic Resonance Arthrogram Outperforms Standard Magnetic Resonance Imaging 2 Weeks After First Shoulder Dislocation for Labral Tear Diagnosis

PURPOSE

To determine the comparative accuracy and precision of routine magnetic resonance imaging (MRI) versus magnetic resonance (MR) arthrogram in measuring labral tear size as a function of time from a shoulder dislocation.

METHODS

We retrospectively evaluated consecutive patients who underwent primary arthroscopic stabilization between 2012 and 2021 in a single academic center. All patients completed a preoperative MRI or MR arthrogram of the shoulder within 60 days of injury and subsequently underwent arthroscopic repair within 6 months of imaging. Intraoperative labral tear size and location were used as standards for comparison. Three musculoskeletal radiologists independently interpreted tear extent using a clock-face convention. Accuracy and precision of MR labral tear measurements were defined based on location and size of the tear, respectively. Accuracy and precision were compared between MRI and MR arthrogram as a function of time from dislocation.

RESULTS

In total, 32 MRIs and 65 MR arthrograms (total n = 97) were assessed. Multivariate analysis demonstrated that intraoperative tear size, early imaging, and arthrogram status were associated with increased MR accuracy and precision (P < .05). Ordering surgeons preferred arthrogram for delayed imaging (P = .018). For routine MRI, error in accuracy increased by 3.4° per day and error in precision increased by 2.3° per day (P < .001) from time of injury. MR arthrogram, however, was not temporally influenced. Significant loss of accuracy and precision of MRI compared with MR arthrogram occurred at 2 weeks after an acute shoulder dislocation.

CONCLUSIONS

Compared with MR arthrogram, conventional MRI demonstrates time-dependent loss of accuracy and precision in determining shoulder labral tear extent after dislocation, with statistical divergence occurring at 2 weeks.

LEVEL OF EVIDENCE

Level II, retrospective radiographic diagnostic study.

Accuracy of MR arthrography in the detection of posterior glenoid labral injuries of the shoulder

OBJECTIVE

The purpose of this study is to evaluate the accuracy of MR arthrography in detecting isolated posterior glenoid labral injuries using arthroscopy as the reference standard.

METHODS

MR arthrograms of 97 patients with isolated posterior glenoid labral tears by arthroscopy and those of 96 age and gender-matched controls with intact posterior labra were reviewed by two blinded radiologists for the presence and location of posterior labral abnormalities. The sensitivity and specificity of detection of posterior labral tears were calculated as well as the prevalence of associated pathologies. Medical records were reviewed for demographics, history and direction of shoulder instability, and prior surgery.

RESULTS

Posterior labral pathology was detected by MR arthrography with sensitivities of 76% and 84% for readers 1 and 2, and a specificity of 88% for both readers. Kappa value for interreader agreement was 0.91. Twenty-two of twenty-three (96%) tears isolated to the posteroinferior quadrant on arthroscopy were correctly identified on MRI. Commonly associated pathologies included paralabral cyst (38%), humeral fracture (7%), and glenoid fracture (2%). Fifteen of ninety-seven (16%) patients with posterior tears on both arthroscopy and MRI had glenoid rim deficiency on imaging versus no patients with intact posterior labra (p < 0.001). Forty of ninety-seven (41%) patients with posterior tears on arthroscopy had a history of posterior instability versus none without posterior tears. There was no significant difference in tear length on MRI between those with a history of instability and those without (p = 0.56).

CONCLUSION

MR arthrography is accurate in detecting posterior glenoid labroligamentous injuries.

Utilization of MRI in surgical decision making in the shoulder

Background

The aim of this study is to evaluate both the utility of MRI scans and reports used in the current practice routine of shoulder surgeons and their surgical decision-making process.

Methods

Ninety-three shoulder-specialised orthopaedic surgeons of the Canadian Shoulder and Elbow Society (CSES) Orthopaedic Association were surveyed in 2020 anonymously online to help identify the use of MR-imaging and reports in managing shoulder disorders and surgical decision process.

Results

Thirty out of 93 (32.25%) CSES fellowship-trained orthopaedic surgeons participated. Respondents request MRI scans in about 55% of rotator cuff (RC) pathology and 48% of shoulder instability cases. Fifty percent of patients with potential RC pathology arrive with a completed MRI scan prior first orthopaedic consult. Their surgical decision is primarily based on patient history (45–55%) and physical examination (23–42%) followed by MRI scan review (2.6–18%), reading MRI reports (0–1.6%) or viewing other imaging (3–23%) depending on the shoulder disease. Ninety percent of surgeons would not decide on surgery in ambiguous cases unless the MR-images were personally reviewed. Respondents stated that shoulder MRI scans are ordered too frequently prior specialist visit as identified in more than 50% of cases depending on pathology.

Conclusions

The decision-making process for shoulder surgery depends on the underlying pathology and patient history. The results demonstrate that orthopaedic surgeons are comfortable reviewing shoulder MRI scans without necessarily reading the MRI report prior to a surgical decision. MRI scans are becoming an increasingly important part of surgical management in shoulder pathologies but should not be used without assessment of patient history and or physical examination.

An assessment of SLAP type 5 lesions using proton density oblique sagittal imaging in magnetic resonance arthrography

BACKGROUND

Bankart lesions accompany superior labrum anteroposterior (SLAP) lesions; these are called SLAP type 5.

PURPOSE

To compare SLAP type 5 lesions using routine magnetic resonance arthrography (MRA) and thin-slice oblique sagittal proton density (PDW) sequences and correlation operation results.

MATERIAL AND METHODS

In total, 181 patients were admitted with shoulder instability. The study was completed with 44 patients. The presence or absence of isolated Bankart and SLAP type 5 lesions in routine MRA and PDW oblique sagittal images were evaluated separately. Absence of rupture scored 0 points, suspected ruptures scored 1 point, and apparent ruptures scored 2 points. The two scores were compared with the shoulder arthroscopy findings.

RESULTS

According to the findings in the shoulder arthroscopy, 40 patients had Bankart lesions and 17 patients had accompanying SLAP type 5 lesions. To detect a Bankart lesion, there was no significant difference between routine MRA sequences and PDW oblique sagittal images (P = 0.061). Routine MRA sensitivity was 95%, specificity 25%, positive predictive value (PPV) 92%, negative predictive value (NPV) 33%, while for PDW oblique sagittal images, sensitivity was 75%, specificity 100%, PPV 100%, and NPV 28.5%. In 8/17 type 5 SLAP lesions, routine MRA detected sensitivity 47%, specificity 92.6%, PPV 80%, and NPV 73.5%; in 14/17 SLAP type 5 lesions, PDW oblique sagittal images detected sensitivity 82%, specificity 100%, PPV 100%, and NPV 90% (P = 0.015).

CONCLUSION

The PDW oblique sagittal images may play a significant role in assessing the anterior and superior extent of the tears.

Shoulder MR Arthrography: Comparative Evaluation of Three Different Contrast Injection Techniques Using an Anterior Approach

BACKGROUND

MR arthrography (MRA) is commonly used in the assessment of shoulder internal derangements. Correct intra-articular contrast injection is required for this modality. Anterior injections under fluoroscopic, ultrasound-guidance, or without image-guidance have been described in the literature. However, no simultaneous comparison has been performed between the three techniques.

PURPOSE

To compare the accuracy and performance of fluoroscopy (FL)-guided, ultrasound (US)-guided and non-image-guided intra-articular contrast injection via an anterior approach for performing shoulder MRA.

STUDY TYPE

Prospective.

SUBJECTS

Two-hundred and ten patients (180 men and 30 women; mean age, 33 ± 12 years; range 20-60 years) with clinically suspected shoulder pathology.

FIELD STRENGTH/SEQUENCE

1.5T/fat-suppressed T₁ -weighted, T₂ -weighted, and 3D-gradient-echo images.

ASSESSMENT

Patients underwent shoulder MRA after anterior intra-articular contrast injection under FL- or US-guidance or without image-guidance. Patients were randomized among the three techniques with each group comprising 70. The techniques were compared according to the accuracy of intra-articular needle placement, attempts success rate, pain during and 24 hours after injection, procedure times, contrast extravasation rate, joint distension, and MRA diagnostic efficacy. Pain was assessed by the visual analog scale (VAS) pain-score.

STATISTICAL TESTS

Pearson's chi-squared and Kruskal-Wallis tests.

RESULTS

FL- and US-guided injections (100% accuracy) were significantly more accurate than non-image-guided (85.7% accuracy) (P < 0.05). US-guidance was the least painful, with statistical differences between image-guided and non-image-guided techniques regarding the first attempt success rate (95.7% and 92.8% for FL- and US-guided vs. 78.6% for blinded), VAS-score 24 hours-post-procedure (1.7 ± 1.7, and 1.5 ± 1.4 vs. 2.2 ± 1.4), procedure time (11.9 ± 1.6, and 7.4 ± 1.7 vs. 4.3 ± 0.76 minutes), and contrast extravasation rate (5.7%, and 8.6% vs. 30%) (all P < 0.05). Procedure time was also significantly different between FL and US-guidance (P < 0.05).

DATA CONCLUSION

Imaging-guided injections are more accurate and tolerable than non-image-guided and should be considered to confirm intra-articular needle position, hence adequate capsular distension and good diagnostic quality of shoulder MRA. US guidance is a less painful, rapid, and safe alternative to the FL approach. Evidence Level: 2 Technical Efficacy Stage: 5. J. MAGN. RESON. IMAGING 2021;53:481-490.

MR arthrography of the shoulder: evaluation of isotropic 3D intermediate-weighted FSE and hybrid GRE T1-weighted sequences

PURPOSE

To compare the diagnostic accuracy of three-dimensional (3D) fast spin echo (FSE) intermediate-weighed (IW-3D) and 3D hybrid double-echo steady-state T1-weighted sequences (Hy-3D) and two-dimensional (FSE) images (2D) at shoulder MR arthrography (MRA).

MATERIALS AND METHODS

Institutional review board approval was obtained and informed consent was waived for this retrospective study. From September 2011 to October 2014, 102 patients who had undergone 1.5 Tesla MRA of the shoulder, including conventional 2D-FSE and IW-3D and Hy-3D images were included in our study. The mean interval between MRA and surgery was 21 days (range 2-70 days). MR images were retrospectively and independently reviewed by two experienced radiologists blinded to the clinical and surgical data. Supraspinatus tendon (SST), infraspinatus tendon (IST) and subscapularis tendon (SCT) tears, as well as antero-inferior, superior and posterior labral lesions were assessed, using surgery as the reference standard. Each reader's performance in assessing rotator cuff and labrum abnormalities was evaluated using the area under the receiver operating characteristic curve (AUC) and 95% confidence intervals (CIs). The difference was evaluated using a univariate z test. The sensitivity, specificity, positive predictive values (PPV), negative predictive values (NPV) and accuracy (Acc) for all types of rotator cuff tears and labral lesions were calculated. A value of p < 0.05 was considered statistically significant. Inter-observer agreement was calculated using kappa statistics.

RESULTS

The difference of diagnostic accuracy achieved was not significant (p > 0.05). In particular, differences in AUC values ranged from 0.002 (p = 0.98) to 0.014 (p = 0.82) as regards the comparison between 2D and IW-3D images, from 0.002 (p = 0.98) to 0.034 (p = 0.08) concerning the comparison between 2D and Hy-3D images and from 0.010 (p = 0.82) to 0.032 (p = 0.09) when comparing Hy-3D to IW-3D images. Accuracy values in evaluating RC lesions and labral lesions were 95.1, 92.1, 91.2, 93.1, 93.1 and 94.1% by reading 2D, Hy-3D and IW-3D images, respectively. The difference of diagnostic accuracy achieved using the datasets analyzed was not significant (p > 0.05). Inter-observer agreement was very good for each of the datasets that were evaluated, with near-perfect agreement for 2D dataset (k = 0.86), Hy-3D (k = 0.81) and IW-3D (k = 0.83).

CONCLUSIONS

The accuracy of IW-3D and Hy-3D images was not significantly higher than the 2D sequences in evaluating RC and labral lesions.

Utility of pre- and post-MR arthrogram imaging of the shoulder: effect on patient care

OBJECTIVE

MR arthrogram imaging of the shoulder is considered more accurate in assessing shoulder pathology than conventional MRI. Arthrography is a minimally invasive procedure. However, most patients prefer to have conventional MRI rather than MR arthrogram imaging. We report the benefit of assessing pre-arthrogram conventional MRI, to determine whether an MR arthrogram is needed for further evaluation.

METHODS

100 consecutive conventional shoulder MR and MR arthrography examinations performed on the same patients were reviewed retrospectively by independent reading of 2 musculoskeletal radiologists. Both conventional MR and MR arthrogram examinations were performed on each patient on the same day. Conventional MR and MR arthrogram examinations were assessed for labral tears and supraspinatus tendon tears. All patients went on to arthroscopy.

RESULTS

Of these 100 patients, 43 patients had superior labral anterior to posterior (SLAP) tears, 28 patients had posterior labral tears, 23 patients had anterior labral tears and 47 patients had full-thickness supraspinatus tendon tears on conventional MR examination reading by Reader 1. There were 42 SLAP tears, 26 posterior labral tears, 24 anterior labral tears and 47 full-thickness supraspinatus tendon tears on conventional MR examination read by Reader 2. On MR arthrogram examination, 51 patients had SLAP tears, 33 patients had posterior labral tears, 29 patients had anterior labral tears and 49 patients had full-thickness supraspinatus tendon tears on reading by Reader 1. On MR arthrogram examination, 50 patients had SLAP tears, 31 patients had posterior labral tears, 30 patients had anterior labral tears and 49 patients had full-thickness supraspinatus tendon tears read by Reader 2. MR arthrogram detected eight SLAP tears, five posterior labral tears, six anterior labral tears and two supraspinatus tendon tears not detected on conventional MR examination read by Reader 1. MR arthrogram detected eight SLAP tears, five posterior labral tears, six anterior labral tears and two supraspinatus tendon tears not detected on conventional MR examination read by Reader 2. 18 of the 21 patients with additional finding on MR arthrogram examination had normal appearing conventional MR examinations.

CONCLUSION

Use of pre- and post-MR arthrogram imaging may benefit patient care. When positive findings are demonstrated on MR examination, few additional findings are demonstrated on MR arthrogram examination. These patients may not need to proceed to MR arthrography. If the conventional MR examination is negative, then additional information may be obtained by proceeding to MR arthrography.

ADVANCES IN KNOWLEDGE

When positive findings are demonstrated on MR examination, few additional findings are demonstrated on MR arthrogram examination. These patients may not need to proceed to MR arthrography. If the conventional MR examination is negative, then additional information may be obtained by proceeding to MR arthrography.

[Systematics of shoulder instability]

Shoulder instability is defined as a symptomatic abnormal motion of the humeral head relative to the glenoid during active shoulder motion. Glenohumeral instabilities are classified according to the causative factors as the pathogenesis of instability plays an important role with respect to treatment options. Instabilities are classified into traumatic and atraumatic instabilities as part of a multidirectional instability syndrome and into microtraumatic instabilities.For diagnostics plain radiographs ("trauma series") are performed to document shoulder dislocation and its successful repositioning. Direct magnetic resonance (MR) arthrography is the most important imaging modality for delineation of the different injury patterns of the labral-ligamentous complex and bony structures. Monocontrast computed tomography (CT) arthrography with the use of multidetector CT scanners represents an alternative imaging modality; however, MR imaging should be preferred in the work-up of shoulder instabilities due to the mostly younger age of patients.

Is the Apprehension Test Sufficient for the Diagnosis of Anterior Shoulder Instability in Young Patients without Magnetic Resonance Imaging (MRI)?

Introduction: The purpose of this study is to compare the sensitivities and positive predictive values (PPV) of the anterior apprehension test and magnetic resonance imaging (MRI) in the diagnosis of anterior labral tears in young patients with shoulder instability and to determine if surgery could be carried without this investigation in selected patients. Materials and Methods: We undertook a retrospective study of 168 patients aged between 15 and 30 years with a history of shoulder dislocation and compared the sensitivities and the PPV of the apprehension test with both MRI and magnetic resonance arthrograms (MRA) in the diagnosis of a Bankart lesion. The radiological investigations were interpreted by general practice radiologists and specialised musculoskeletal radiologists. All patients had their diagnosis confirmed by shoulder arthroscopy. Results: Our results showed that the apprehension test was highly reliable when it was positive with a PPV of 96%. It was more sensitive than MRI in the diagnosis of a Bankart lesion. The clinical test was significantly better when a musculoskeletal radiologist interpreted the MRI. The MRA interpreted by a musculoskeletal radiologist had the highest rates of sensitivity in detecting Bankart lesions. The figure was similar to that for the apprehension test. There was no difference in the PPVs among the clinical test, the MRI and the MRA read by the 2 categories of radiologists. Conclusion: We conclude that a routine MRI may be unnecessary in evaluating a young patient with clinically evident anterior shoulder instability if the apprehension test is positive. A MRA that can be interpreted by a musculoskeletal radiologist will be the next best investigation if the clinical test is negative or equivocal. Key words: Dislocation, Glenohumeral joint, Radiological investigations