Superior labral anteroposterior lesions: MR arthrography with arm traction

SSR white paper: guidelines for utilization and performance of direct MR arthrography

OBJECTIVE

Direct magnetic resonance arthrography (dMRA) is often considered the most accurate imaging modality for the evaluation of intra-articular structures, but utilization and performance vary widely without consensus. The purpose of this white paper is to develop consensus recommendations on behalf of the Society of Skeletal Radiology (SSR) based on published literature and expert opinion.

MATERIALS AND METHODS

The Standards and Guidelines Committee of the SSR identified guidelines for utilization and performance of dMRA as an important topic for study and invited all SSR members with expertise and interest to volunteer for the white paper panel. This panel was tasked with determining an outline, reviewing the relevant literature, preparing a written document summarizing the issues and controversies, and providing recommendations.

RESULTS

Twelve SSR members with expertise in dMRA formed the ad hoc white paper authorship committee. The published literature on dMRA was reviewed and summarized, focusing on clinical indications, technical considerations, safety, imaging protocols, complications, controversies, and gaps in knowledge. Recommendations for the utilization and performance of dMRA in the shoulder, elbow, wrist, hip, knee, and ankle/foot regions were developed in group consensus.

CONCLUSION

Although direct MR arthrography has been previously used for a wide variety of clinical indications, the authorship panel recommends more selective application of this minimally invasive procedure. At present, direct MR arthrography remains an important procedure in the armamentarium of the musculoskeletal radiologist and is especially valuable when conventional MRI is indeterminant or results are discrepant with clinical evaluation.

Advantages of the Use of Axial Traction Magnetic Resonance Imaging (MRI) of the Shoulder in Patients with Suspected Rota-Tor Cuff Tears: An Exploratory Pilot Study

Magnetic Resonance Imaging (MRI) with axial traction is a tool for the assessment of musculoskeletal pathology. Previous reports have demonstrated a better distribution of intra-articular contrast material. No investigations were performed to evaluate glenohumeral joint axial traction MRI in patients with suspected rotator cuff tears. This study aims to assess the morphological changes and the potential advantage of glenohumeral joint axial traction MRI without intra-articular contrast administration in patients with suspected rotator cuff tears. Eleven patients with clinical suspicion of rotator cuff tears underwent a shoulder MRI scan with and without axial traction. PD weighted images with SPAIR fat saturation technique and T1 weighted images with TSE technique were acquired in the oblique coronal, oblique sagittal and axial planes. Axial traction allowed a significant widening of the subacromial space (11.1 ± 1.5 mm vs. 11.3 ± 1.8 mm; p = 0.001) and inferior glenohumeral space (8.6 ± 3.8 mm vs. 8.9 ± 2.8 mm; p = 0.029). With axial traction, there was a significant decrease in measurements of the acromial angle (8.3 ± 10.8° vs. 6.4 ± 9.8°; p < 0.001) and gleno-acromial angle (81 ± 12.8° vs. 80.7 ± 11.5°; p = 0.020). Our investigation demonstrates for the first time significant morphological changes in the shoulder of patients with suspected rotator cuff tears who underwent a glenohumeral joint axial traction MRI.

Effects of Magnetic Resonance Imaging With Axial Traction of the Thumb Carpometacarpal Joint on Articular Cartilage Visibility: A Feasibility Study

Objectives

The objective of this study was to verify the usefulness of magnetic resonance imaging (MRI) with axial traction of the thumb for observing articular cartilage.

Materials and methods

Eleven healthy adult volunteers (39.7 ± 7.4 years) without thumb carpometacarpal joint arthritis or trauma were included in this study. A 3-tesla (3T) MRI (Magnetom Skyra, Siemens Healthineers AG, Munich, Germany) of the right thumb with axial traction applied by a finger trap with three traction weights (0, 2, and 5 kg) was performed. A 3D T2* multiecho data imaging combination (MEDIC) was selected to visualize the articular cartilage. After multiplanar reconstruction, sagittal and coronal images of the thumb carpometacarpal joint were used to evaluate the articular cartilage visibility and joint space widths at five locations. Articular cartilage visibility was evaluated using our original classification method that used the percentage of the cartilage detectable area. The Friedman test was used to compare the differences between each traction weight and location.

Results

Articular cartilage visibility significantly improved with axial traction. The average joint space widths with the 5-kg application were 1.9 ± 0.8, 3.9 ± 0.6, 2.0 ± 0.9, 3.9 ± 1.1, and 2.5 ± 1.4 mm at the center, volar edge, dorsal edge, radial edge, and ulnar edge, respectively. The joint space widths significantly increased proportionally with the traction weight at all locations. The joint space widths at the volar and radial edges were significantly greater than those at other locations.

Conclusion

Applying axial traction to the thumb increased the joint space widths and improved the visibility of the articular cartilage in the carpometacarpal joint on MRI.

Correlation Between Clinical Diagnosis, MRI, and Arthroscopy in Diagnosing Shoulder Pathology

Introduction

Shoulder disorders are frequently encountered by clinicians and are a common cause of musculoskeletal pain in the general population. Clinical tests specific to each shoulder pathology, MRI, and arthroscopy are the most relied upon modalities of diagnosis used by many clinicians. The aim of this study was to correlate clinical tests and MRI with arthroscopy as the gold standard and whether a negative MRI with a positive clinical test could justify an arthroscopy.

Materials and methods

A total of 120 consecutive patients who had a history of shoulder pain or instability were evaluated by clinical tests and MRI, and underwent arthroscopy. Based on the confirmatory findings of arthroscopy, they were classified as True Positive (TP), True Negative (TN), False Positive (FP) and False Negative (FN) for each modality i.e., clinical tests and MRI.

Results

Clinical assessment of rotator cuff tears in comparison to arthroscopy yielded a sensitivity of 96.88%, specificity of 92.86% and diagnostic accuracy of 95%, whilst MRI had a sensitivity of 90.62%, specificity of 92.86% and diagnostic accuracy of 91.67%. In anterior labral lesions, clinical assessment had a sensitivity of 94.44%, specificity of 97.62 % and diagnostic accuracy of 96.67%, whilst MRI had a sensitivity of 83.33%, specificity of 92.86%, with diagnostic accuracy of 90%. Interestingly, in the clinical assessment of superior labral tear from anterior to posterior (SLAP) lesions, a sensitivity of 90%, specificity of 95%, and diagnostic accuracy of 93.33% were observed while MRI had a sensitivity of 60%, specificity of 92.50%, and diagnostic accuracy of 81.67%.

Conclusion

On the basis of these results, clinical assessment appears to be an effective tool in diagnosing shoulder pathologies, whereas MRI, though reliable in the identification of rotator cuff tears and instability, does not identify patients with SLAP lesions effectively. This study reinforces the importance of a good clinical examination of the shoulder, especially in chronic pain and an uncertain MRI, therefore improving patient management.

Imaging of shoulder instability

The shoulder enjoys the widest range of motion of all the joints in the human body, therefore requires a delicate balance between stability and motility. The glenohumeral joint is inclined to fall into two main instability categories: macro and micro. Macroinstability can be traumatic or atraumatic, with anterior or posterior dislocation of the humeral head. Microinstability falls within the broader section of acquired instability in overstressed shoulder caused by repeated joint stress. Anterior traumatic instability is the most frequent entity and a relatively common injury in young and athletic population. While shoulder instability is a clinical diagnosis, imaging impacts the patient management by detailing the extent of injury, such as capsulo-labral-ligamentous tears, fracture, and/or dislocation, describing the predisposing anatomic conditions and guide the therapetic choice. The aim of this comprehensive review is to cover the imaging findings of shoulder instability by different imaging techniques.

Effect of elbow MRI with axial traction on articular cartilage visibility-a feasibility study

OBJECTIVE

Accurate evaluation of the articular cartilage of the elbow using MRI is sometimes challenging because of its anatomical complexity and relatively small size. Moreover, the articular cartilage of the humerus is in close contact with the opposing cartilage surfaces. Magnetic resonance arthrography with traction was reported to resolve this issue; however, less invasive methods are desirable. This study aimed to assess the effect of MRI with axial traction (without arthrography) on joint space widening and cartilage outline visibility of the elbow.

MATERIALS AND METHODS

We enrolled 10 volunteers (female = 1; mean age, 36.7 ± 8.6; range 28-56) and performed MRI with and without axial traction on the elbow. Joint space widths were measured, and the humeral articular cartilage outline visibility was evaluated at the radiocapitellar joint and lateral one-third and medial one-third of the ulnohumeral joints. Measurements were compared using the Wilcoxon signed-rank test. Significance was set at p < 0.05. Volunteers scored pain and discomfort during MRI with traction using the visual analog scale in a questionnaire format.

RESULTS

Traction significantly increased joint space width at the radiocapitellar joint. Humeral articular cartilage outline visibility also significantly improved at the radiocapitellar joint. Pain and discomfort scores during traction MRI were low.

CONCLUSION

MRI of the elbow with traction widens joint space and enables better articular cartilage visibility at the radiocapitellar joint. Anatomical features of the elbow might have affected these results. Therefore, it would be safe and useful for evaluating elbow injuries involving articular cartilage lesions.

Efficacy of the Rotational Traction Method in the Assessment of Glenohumeral Cartilage Surface Area in Computed Tomography Arthrography

OBJECTIVE

We aimed to investigate the efficacy of the rotational traction method in expanding the joint space and enabling the assessment of an extended surface area.

METHODS

Sixty patients who underwent computed tomography arthrography were evaluated in the study: 30 with and 30 without the help of rotational traction. The subgroups consisted of patients with adhesive capsulitis, habitual luxation, or labral tears. Areas of obscured joint surface by coalescent cartilages were calculated using computer software, and those belonging to the traction and nontraction groups along with subgroups were compared statistically.

RESULTS

There was a significant difference between the traction and nontraction group regarding the contact surface area (P < 0.001 for both observers). In patients with adhesive capsulitis, the contact surface area was larger compared with the other subgroups (P = 0.002 for observer 1 and P = 0.002 for observer 2). In patients with habitual luxation, the contact surface area was smaller compared with the other subgroups (P = 0.002 for observer 1 and P = 0.001 for observer 2).

CONCLUSIONS

Expansion of joint distance is important for assessing the joint cartilage. The rotational traction method provides effective separation of the joint space. For this reason, rotational traction can be used effectively in patients in whom the joint cartilage is to be evaluated.

MR Imaging of SLAP Lesions

Background:

SLAP lesions of the shoulder are challenging to diagnose by clinical means alone. Interpretation of MR images requires knowledge of the normal appearance of the labrum, its anatomical variants, and the characteristic patterns of SLAP lesions. In general, high signal extending anterior and posterior to the biceps anchor is the hallmark of SLAP lesions. Common diagnostic criteria for a SLAP lesion by MR or MR arthrography include the following: presence of a laterally curved, high signal intensity in the labrum on a coronal image, multiple or branching lines of high signal intensity in the superior labrum on a coronal image, full-thickness detachment with irregularly marginated high signal intensity and/or separation >2 mm on conventional MRI or 3 mm on MR arthrography between the labrum and glenoid on a coronal image, and a paralabral cyst extending from the superior labrum.

Methods:

MR diagnosis of SLAP tears may be improved with provocative maneuvers, such as longitudinal traction of the arm or positioning of the shoulder in abduction and external rotation during imaging. The use of intra-articular contrast distends the joint similar to what occurs during arthroscopy and forced diffusion under the labrum may improve the ability to detect SLAP lesions that might not be seen with standard MR. Improved diagnostic accuracy for SLAP tears is seen with 3-T compared with 1.5-T MR imaging, with or without intra-articular contrast material.

Conclusion:

Regardless of MR findings, however, physicians should be cautious when recommending surgery in the patient with a vague clinical picture. The patient’s history, physical exam, and imaging evaluation all should be considered together in making the decision to proceed with surgery.

Imaging the Glenoid Labrum and Labral Tears

The shoulder joint is the most unstable articulation in the entire human body. While this certainly introduces vulnerability to injury, it also confers the advantage of broad range of motion. There are many elements that work in combination to offset the inherent instability of the glenohumeral joint, but the glenoid labrum is perhaps related most often. Broadly, clinical unidirectional instability can be subdivided into anterior and posterior instability, which usually raise concern for anteroinferior and posteroinferior labral lesions, respectively. In the special case of superior labral damage, potential dislocation is blocked by structures that include the acromion; hence, while damage elsewhere commonly manifests as clinical instability, damage to the superior labrum is often described by the term microinstability. In this particular case, one of the radiologist's main concerns should be classic superior labral anteroposterior lesions. The glenoid labrum is also subject to a wide range of normal variants that can mimic labral tears. Knowledge of these variants is central to interpreting an imaging study of the labrum because misdiagnosis of labral variants as tears can lead to superfluous surgical procedures and decreased shoulder mobility. This article reviews labral anatomy and normal labral variants, describes their imaging features, and discusses how to discriminate normal variants from labral tears. Specific labral pathologic lesions are described per labral quadrant (anteroinferior, posteroinferior, and superior), and imaging features are described in detail. Online supplemental material is available for this article. ^©RSNA, 2016.

Ankle Traction During MRI of Talar Dome Osteochondral Lesions

OBJECTIVE

The objective of our study was to assess the impact of axial traction during MRI of talar dome osteochondral lesions using a small-FOV coil.

SUBJECTS AND METHODS

A prospective study of 33 patients undergoing high-resolution MRI of the ankle using a microscopy coil with and without axial traction was performed. Two radiologists independently measured the tibiotalar joint space width and semiquantitatively graded intraarticular joint fluid dispersion, cartilage surface visibility of the osteochondral lesion, and cartilage surface visibility elsewhere in the tibiotalar joint before and after traction. Patients were instructed to report any discomfort during ankle traction.

RESULTS

None of the patients reported discomfort or other symptoms during ankle traction. The tibiotalar joint space significantly increased (increase in cartilage-cartilage distance, 0.5-0.7 mm; all, p < 0.05) after traction compared with before traction. The degree of intraarticular joint fluid dispersion and the cartilage surface visibility at the osteochondral lesion and elsewhere in the tibiotalar joint improved after traction (all, p < 0.05).

CONCLUSION

Traction MRI of the ankle is safe and technically feasible. This study is the first to date to investigate the effect of ankle traction on the MRI assessment of talar dome osteochondral lesions. Traction improves cartilage surface visibility of talar dome osteochondral lesions.

Axial traction magnetic resonance imaging (MRI) of the glenohumeral joint in healthy volunteers: initial experience

OBJECTIVE

Evaluate technical feasibility and potential applications of glenohumeral (GH) joint axial traction magnetic resonance imaging (MRI) in healthy volunteers.

MATERIALS AND METHODS

Eleven shoulders were imaged in neutral and with 4kg axial traction at 3T. Quantitative measurements were assessed.

RESULTS

Axial traction was well tolerated. There was statistically significant widening of the superior GH joint space (p=0.002) and acromial angle (p=0.017) with traction. Inter-rater agreement was high.

CONCLUSION

GH joint axial traction MRI is technically feasible and well tolerated in volunteers. Traction of the capsule, widening of the superior GH joint space and acromial angle were observed.

Elbow MR arthrography with traction

OBJECTIVE

To assess the effect of axial traction during MR arthrography (MRA) of the elbow joint on joint space widening, contrast dispersion between opposing cartilage surfaces and cartilage surface visibility.

METHODS

11 patients with elbow MRA with and without axial traction were prospectively studied. Two radiologists independently measured the elbow joint space width and semi-quantitatively graded contrast material dispersion between the opposing cartilage surfaces as well as the articular cartilage surface visibility before and after traction. The detection and visibility of articular cartilage defects were also compared before and after traction. Patients were instructed to report on pain or any other symptoms during elbow traction.

RESULTS

No patient reported discomfort, pain or any other symptoms related to traction on immediate and intermediate-term follow-up. Joint space width increased, more at the radiocapitellar joint space (Δ = 0.63 mm, p = 0.005) than at the ulnotrochlear joint space (Δ = 0.17 mm, p = 0.012), with contrast dispersion into the radiocapitellar joint and cartilage visibility of the radiocapitellar joint space significantly improving after traction (all p < 0.05). All of these parameters also improved at the ulnotrochlear joint, although this did not reach statistical significance. Traction improved the visibility of cartilage defects.

CONCLUSION

This is the first study to evaluate the effect of traction on MRA of the elbow joint. This technique is safe and technically feasible. Traction MRA improves the cartilage surface visibility and cartilage defect visibility.

ADVANCES IN KNOWLEDGE

This technique is safe and technically feasible. Traction MRA improves cartilage surface visibility and cartilage defect visibility.

Beyond the Cuff: MR Imaging of Labroligamentous Injuries in the Athletic Shoulder

Shoulder disease is common in the athletic population and may arise as a consequence of a single traumatic episode or multiple repeated events. Associated labroligamentous injuries can result in substantial disability. Specific athletic and occupational activities result in predictable injury patterns. Imaging in general and magnetic resonance (MR) imaging, in particular, are vital in establishing the correct diagnosis and excluding common mimicking conditions, to ensure timely and appropriate management. In this review, the utility of MR imaging and MR arthrography will be explored in evaluation of shoulder disease, taking into account normal variants of the labroligamentous complex. Subsequently, broad categories of labral lesions and instability, external and internal impingement, as well as nerve entrapment syndromes, will be discussed, while emphasizing their imaging findings in the clinical context and illustrating key features. More recent concepts of internal impingement and secondary subacromial impingement will also be clarified.

SLAP lesions: a treatment algorithm

Tears of the superior labrum involving the biceps anchor are a common entity, especially in athletes, and may highly impair shoulder function. If conservative treatment fails, successful arthroscopic repair of symptomatic SLAP lesions has been described in the literature particularly for young athletes. However, the results in throwing athletes are less successful with a significant amount of patients who will not regain their pre-injury level of performance. The clinical results of SLAP repairs in middle-aged and older patients are mixed, with worse results and higher revision rates as compared to younger patients. In this population, tenotomy or tenodesis of the biceps tendon is a viable alternative to SLAP repairs in order to improve clinical outcomes. The present article introduces a treatment algorithm for SLAP lesions based upon the recent literature as well as the authors' clinical experience. The type of lesion, age of patient, concomitant lesions, and functional requirements, as well as sport activity level of the patient, need to be considered. Moreover, normal variations and degenerative changes in the SLAP complex have to be distinguished from "true" SLAP lesions in order to improve results and avoid overtreatment. The suggestion for a treatment algorithm includes: type I: conservative treatment or arthroscopic debridement, type II: SLAP repair or biceps tenotomy/tenodesis, type III: resection of the instable bucket-handle tear, type IV: SLAP repair (biceps tenotomy/tenodesis if >50 % of biceps tendon is affected), type V: Bankart repair and SLAP repair, type VI: resection of the flap and SLAP repair, and type VII: refixation of the anterosuperior labrum and SLAP repair.

3-T direct MR arthrography of the wrist: value of finger trap distraction to assess intrinsic ligament and triangular fibrocartilage complex tears

PURPOSE

To determine the value of applying finger trap distraction during direct MR arthrography of the wrist to assess intrinsic ligament and triangular fibrocartilage complex (TFCC) tears.

MATERIALS AND METHODS

Twenty consecutive patients were prospectively investigated by three-compartment wrist MR arthrography. Imaging was performed with 3-T scanners using a three-dimensional isotropic (0.4 mm) T1-weighted gradient-recalled echo sequence, with and without finger trap distraction (4 kg). In a blind and independent fashion, two musculoskeletal radiologists measured the width of the scapholunate (SL), lunotriquetral (LT) and ulna-TFC (UTFC) joint spaces. They evaluated the amount of contrast medium within these spaces using a four-point scale, and assessed SL, LT and TFCC tears, as well as the disruption of Gilula's carpal arcs.

RESULTS

With finger trap distraction, both readers found a significant increase in width of the SL space (mean Δ = +0.1mm, p ≤ 0.040), and noticed more contrast medium therein (p ≤ 0.035). In contrast, the differences in width of the LT (mean Δ = +0.1 mm, p ≥ 0.057) and UTFC (mean Δ = 0mm, p ≥ 0.728) spaces, as well as the amount of contrast material within these spaces were not statistically significant (p = 0.607 and ≥ 0.157, respectively). Both readers detected more SL (Δ = +1, p = 0.157) and LT (Δ = +2, p = 0.223) tears, although statistical significance was not reached, and Gilula's carpal arcs were more frequently disrupted during finger trap distraction (Δ = +5, p = 0.025).

CONCLUSION

The application of finger trap distraction during direct wrist MR arthrography may enhance both detection and characterisation of SL and LT ligament tears by widening the SL space and increasing the amount of contrast within the SL and LT joint spaces.

Cartilage assessment of the metacarpophalangeal joints: cadaveric study with magnetic resonance arthrography and finger traction

We investigated the efficacy of axial traction of the fingers combined with magnetic resonance (MR) arthrography in assessing the metacarpophalangeal (MCP) joint cartilage in cadavers. Cartilage was imaged and graded before/after MR arthrography, with/without traction, then correlated with cadaveric sectioning. The application of traction with MR arthrography is a promising technique for improved visualization of the articular cartilage of the MCP joints compared with similar imaging without traction and/or without arthrography, but its true benefit requires further study.

Direct MR arthrography of the shoulder under axial traction: feasibility study to evaluate the superior labrum-biceps tendon complex and articular cartilage

PURPOSE

To assess the value of adding axial traction to direct MR arthrography of the shoulder, in terms of subacromial and glenohumeral joint space widths, and coverage of the superior labrum-biceps tendon complex and articular cartilage by contrast material.

MATERIALS AND METHODS

Twenty-one patients investigated by direct MR arthrography of the shoulder were prospectively included. Studies were performed with a 3 Tesla (T) unit and included a three-dimensional isotropic fat-suppressed T1-weighted gradient-recalled echo sequence, without and with axial traction (4 kg). Two radiologists independently measured the width of the subacromial, superior, and inferior glenohumeral joint spaces. They subsequently rated the amount of contrast material around the superior labrum-biceps tendon complex and between glenohumeral cartilage surfaces, using a three-point scale: 0 = no, 1 = partial, 2 = full.

RESULTS

Under traction, the subacromial (Δ = 2.0 mm, P = 0.0003), superior (Δ = 0.7 mm, P = 0.0001) and inferior (Δ = 1.4 mm, P = 0.0006) glenohumeral joint space widths were all significantly increased, and both readers noted significantly more contrast material around the superior labrum-biceps tendon complex (P = 0.014), and between the superior (P = 0.001) and inferior (P = 0.025) glenohumeral cartilage surfaces.

CONCLUSION

Direct MR arthrography of the shoulder under axial traction increases subacromial and glenohumeral joint space widths, and prompts better coverage of the superior labrum-biceps tendon complex and articular cartilage by contrast material.

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

PURPOSE

Magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA) have gained increasing favour in the assessment of patients with suspected glenoid labral injuries. The purpose of this study was to determine the diagnostic accuracy of MRI or MRA in the detection of gleniod labral lesions.

MATERIALS AND METHODS

A systematic review was undertaken of the electronic databases Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, AMED and CINAHL, in addition to a search of unpublished literature databases. All studies which compared the ability of MRI or MRA (index test) to assess gleniod labral tears or lesions, when verified with a surgical procedure (arthroscopy or open surgery-reference test) were included. Data extraction and methodological appraisal using the QUADAS tool were both conducted by two reviewers independently. Data were analysed through a summary receiver operator characteristic curve and pooled sensitivity and specificity analysis were calculated with 95% confidence intervals.

RESULTS

Sixty studies including 4,667 shoulders from 4,574 patients were reviewed. There appeared slightly greater diagnostic test accuracy for MRA over MRI for the detection of overall gleniod labral lesions (MRA-sensitivity 88%, specificity 93% vs. MRI sensitivity 76% vs. specificity 87%). Methodologically, studies recruited and identified their samples appropriately and clearly defined the radiological procedures. In general, it was not clearly defined why patients were lost during the study, and studies were poor at recording whether the same clinical data were available to the radiologist interpreting the MRI or MRA as would be available in clinical practice. Most studies did not state whether the surgeon interpreting the arthroscopic procedure was blinded to the results of the MR or MRA imaging.

CONCLUSIONS

Based on the available literature, overall MRA appeared marginally superior to MRI for the detection of glenohumeral labral lesions.

LEVEL OF EVIDENCE

Level 2a.

Superior labral anterior-to-posterior lesions: comparison of external rotation and active supination CT arthrography with neutral CT arthrography

PURPOSE

To compare the diagnostic performance of computed tomographic (CT) arthrography performed with external rotation and active supination (ERAS) with that of CT angiography performed in the neutral position for superior labral anterior-to-posterior (SLAP) lesions.

MATERIALS AND METHODS

Institutional review board approval and informed consent were obtained. CT arthrography in neutral and ERAS positions was performed in 49 shoulders of 47 patients, with subsequent arthroscopic confirmation of the status of the superior labrum. Two musculoskeletal radiologists (1 and 8 years of experience) reviewed images and expressed the likelihood of SLAP lesions by using a continuous scale; they also measured gap widths and depths of labral detachment. Overall performances for the detection of SLAP lesions were determined with receiver-operating characteristic (ROC) analysis. Gap widths and depths measured with the two types of CT arthrography were also compared.

RESULTS

For reader 1, area under the ROC curve increased insignificantly from 0.932 in the neutral position to 0.974 in the ERAS position (P = .210), whereas for reader 2, it increased significantly from 0.914 to 0.984 (P = .032). Mean gap width of SLAP lesion was significantly greater according to ERAS CT arthrography (3.98 mm ± 2.48 [standard deviation] vs 1.61 mm ± 1.11), whereas mean gap depth was not significantly different. Gap width and depth cutoff values for the detection of a SLAP lesion with ERAS CT arthrography were 1.7 mm and 1.6 mm, respectively.

CONCLUSION

ERAS CT arthrography might improve the detection of SLAP lesions compared with neutral-position CT arthrography.

Magnetic resonance-guided interventions of large and small joints

Magnetic resonance (MR)-guided interventions of large and small joints are feasible and safe procedures offering several advantages compared with standard guiding techniques. Nevertheless, MR-guided interventions are not routinely performed in daily practice apart from a few centers. Accurate injections are crucial for clinical outcome in diagnostic arthrography as well as therapeutic joint injections. In particular, palpatory joint puncture was shown to be inaccurate or uncertain in a substantial percentage of injections of the shoulder, the hip, and the knee. Magnetic resonance imaging offers respective merits of a cross-sectional technique with high soft-tissue contrast. Exact depiction of structures, which should be preserved, such as the labrum, should be aimed for. Areas with complex anatomy can be approached by adapting the right imaging plane(s) because of multiplanar capacity. Lack of ionizing radiation for patients is of growing interest particularly in young patients with repeated interventions. Magnetic resonance guidance alone allows an "all-in-one" MR arthrography combining precise targeting with high-field-strength imaging. Modern short-bore and open-bore high-field-strength systems offer a good comfort for patients as well as clinicians and enhance patient positioning options such as supine or prone position. Thus, a tailored approach such as a posterior technique for suspected anterior lesions in shoulder MR arthrography is possible.In this article, we describe the advantages and limitations of MR guidance in joint interventions with focus on shoulder and hip interventions. We review the requirements for needle material and MR sequences, discuss several different techniques developed to date, and present current results in clinical outcome.

Displaceability of SLAP lesion on shoulder MR arthrography with external rotation position

OBJECTIVE

To investigate the usefulness of the external rotation (ER) position on magnetic resonance (MR) arthrography for the diagnosis of superior labral anterior to posterior (SLAP) lesion.

MATERIALS AND METHODS

Approval of institutional review board was obtained, and informed consent was waived. The MR arthrograms of 210 shoulders that were arthroscopically confirmed as SLAP lesion in 163 shoulders and intact superior labrum in 47 shoulders were retrospectively reviewed in each neutral and ER position for the diagnosis of SLAP lesion, the extent of distraction of the torn labrum, and the external rotation angle. The sensitivity, specificity, and diagnostic accuracy of MR arthrograms for determining SLAP lesion were assessed in each position. For the arthroscopically confirmed group, the diagnosis of SLAP lesion and the extent of distraction about the tear were compared between neutral and ER positions by Fisher's exact test and the paired t-test. The correlation between the external rotation angle and the diagnosis of SLAP lesion, and between the external rotation angle and the differences in the extent of distraction were evaluated in the ER position using the ANOVA test.

RESULTS

Sensitivity and diagnostic accuracy of MR arthrography for SLAP lesion increased from 64.4% and 71.0% in the neutral position to 78.5% and 81.9% in the ER position, respectively, without change of specificity, which was 93.6% in both positions. The diagnosis of SLAP lesion was changed from negative to SLAP lesion in 16.0% of the arthroscopically confirmed group. Mean difference in the extent of distraction about the tear was 0.69 mm (range -1.40 ∼ 6.67 mm), which was statistically significant. There was no relationship between the external rotation angle and the diagnosis of SLAP lesion, and between the external rotation angle and the differences in the extent of distraction.

CONCLUSION

Shoulder MR arthrography with additional ER positioning helps in the diagnosis of SLAP lesion and provides information about the displaceability of the torn labrum.

Direct magnetic resonance arthrography of the wrist with axial traction: a feasibility study to assess joint cartilage

PURPOSE

To assess the impact of axial traction during acquisition of direct magnetic resonance (MR) arthrography of the wrist with regard to joint space width and amount of contrast material between the opposing cartilage surfaces.

MATERIALS AND METHODS

Fifteen consecutive patients (12 male, mean age 38.1 years) were included in this Institutional Review Board-approved prospective study. Three-compartment wrist MR arthrographies were performed between October and December 2009 on a 3 T unit using a fat-suppressed T1-weighted isotropic high-resolution volumetric interpolated breathhold examination (VIBE) sequence in the coronal plane, with and without axial traction (3 kg). Two radiologists measured radiocarpal (radioscaphoid, radiolunate) and midcarpal (lunocapitate, hamatolunate) joint space widths, with and without traction, and assessed the amount of contrast material between the opposing cartilage surfaces using a three-point scale: 0 = absence, 1 = partial, 2 = complete.

RESULTS

With traction, joint space width increased significantly at the radioscaphoid (Δ = 0.78 mm, P < 0.01), radiolunate (Δ = 0.18 mm, P < 0.01), and lunocapitate (Δ = 0.45 mm, P < 0.01) spaces, and both observers detected significantly more contrast material between the cartilage surfaces. At the hamatolunate space, the differences in joint space width (Δ = 0.14 mm, P = 0.54) and amount of contrast material were not significant.

CONCLUSION

Direct wrist MR arthrography with axial traction of 3 kg increases joint space width at the radiocarpal and lunocapitate spaces, and prompts better coverage of the articular cartilage by the contrast material.

Direct magnetic resonance arthrography of the knee: utility of axial traction

The purpose of this study was to determine the impact of axial traction during acquisition of direct magnetic resonance (MR) arthrography examination of the knee in terms of joint space width and amount of contrast material between the cartilage surfaces. Direct knee MR arthrography was performed in 11 patients on a 3-T MR imaging unit using a T1-weighted isotropic gradient echo sequence in a coronal plane with and without axial traction of 15 kg. Joint space widths were measured at the level of the medial and the lateral femorotibial joint with and without traction. The amount of contrast material in the medial and lateral femorotibial joint was assessed independently by two musculoskeletal radiologists in a semiquantitative manner using three grades ('absence of surface visualization, 'partial surface visualization or 'complete surface visualization'). With traction, joint space width increased significantly at the lateral femorotibial compartment (mean = 0.55 mm, p = 0.0105) and at the medial femorotibial compartment (mean = 0.4 mm, p = 0.0124). There was a trend towards an increased amount of contrast material in the femorotibial compartment with axial traction. Direct MR arthrography of the knee with axial traction showed a slight and significant increase of the width of the femorotibial compartment with a trend towards more contrast material between the articular cartilage surfaces.

Analysis of interobserver and intraobserver variability in the diagnosis and treatment of SLAP tears using the Snyder classification

BACKGROUND

Superior labral anterior posterior lesions are a relatively rare entity, and classification as a basis for selection of treatment has remained a point of controversy.

HYPOTHESIS

There will be substantial interobserver and intraobserver variability in the diagnosis and treatment of superior labral anterior posterior tears by experienced arthroscopic specialists.

STUDY DESIGN

Cohort study (diagnosis), Level of evidence, 2.

METHODS

Compact discs containing 22 video vignettes of approximately 15 seconds duration were sent to the membership of the Arthroscopy Association of North America, American Shoulder and Elbow Society, and AOSSM. Each surgeon was asked to review the vignettes, classify the superior labral anterior posterior lesion type, and provide a treatment recommendation for each vignette. Seventy-three expert surgeons responded to the solicitation with a completed analysis. The same CD-ROM was re-sent to each of these 73 surgeons at a minimum of 12 months after the first viewing to obtain data on intraobserver reliability. Seventeen of the 73 surgeons returned this second CD-ROM with a complete analysis. Demographic data were also obtained from each surgeon. Multivariable logistic regression analysis was used to analyze the data, and 95% confidence intervals were established for each superior labral anterior posterior type (I-IV) with regard to diagnosis and treatment decision.

RESULTS

The 22 vignettes analyzed by 73 surgeons resulted in 1606 responses. Several significant trends were noticed with regard to diagnosis and treatment from the responses: (1) surgeons had difficulty distinguishing type III lesions from type IV lesions, (2) the treatment of type III lesions is much more variable than that of any other subtype, and (3) surgeons had difficulty distinguishing normal shoulders from type II superior labral anterior posterior tears. No relationship was identified between correct treatment decisions based on diagnosis and any of the demographic factors analyzed. Our analysis of intraobserver variability showed only moderate agreement. The analysis of interobserver variability improved significantly when the diagnoses were analyzed based on treatment decision.

CONCLUSIONS

There is substantial interobserver and intraobserver variability among experienced shoulder arthroscopic specialists with regard to diagnosis and treatment of superior labral anterior posterior tears. Intraobserver agreement using the Snyder classification indicated only moderate agreement. Analysis of interobserver agreement based on treatment decisions results in superior concordance among experienced surgeons for the diagnosis of superior labral anterior posterior lesions.

Magnetic resonance imaging accuracy for the diagnosis of superior labrum anterior-posterior lesions in the community setting: eighty-three arthroscopically confirmed cases

Magnetic resonance imaging (MRI) has been shown in the literature to have high accuracy for the diagnosis of superior labrum anterior-to-posterior (SLAP) lesions. However, these studies have been performed at specialized institutions and have not been evaluated for community settings. Our hypothesis was that MRI diagnosis of SLAP lesions in the community setting is not as accurate as suggested by previous literature. The MRI reports for 83 consecutive surgically confirmed type II SLAP lesions were evaluated. The findings regarding the presence of SLAP lesions were documented from the community radiologists' MRI readings. Two blinded, fellowship-trained musculoskeletal radiologists evaluated these same 83 MRIs, as well as 17 MRIs with surgically confirmed normal superior labra. The musculoskeletal radiologists also used a visual analog scale to subjectively grade the quality of each MRI. MRIs were performed at 14 different centers and were read by 28 different community radiologists. There were 37 noncontrast MRIs and 46 MRI arthrograms. The community radiologists accurately identified 51% of the SLAP lesions. The sensitivities for the community radiologists were significantly better for the MRI arthrograms than for the noncontrast MRIs (P = .0002). For the two musculoskeletal radiologists, the sensitivities were 60% and 67.5%, and the specificities were 71% and 76.5%. The accuracies for the musculoskeletal radiologists were 62% and 69%. One of the musculoskeletal radiologists had significant correlation between the visual analog score and MRI diagnostic accuracy (P = .0006). The sensitivity for one of the musculoskeletal radiologists was significantly greater than the sensitivity for the community radiologists (P = .0063). The accuracies between the other musculoskeletal radiologist and the community radiologists were not significantly different (P = .0577). In this community setting, MRI was not accurate for the diagnosis of SLAP lesions. Musculoskeletal radiologists were more accurate than the community radiologists; however, the musculoskeletal radiologists were not as accurate as previous literature might predict.

Imaging of the painful shoulder in throwing athletes

A wide spectrum of abnormalities can affect the throwing shoulder. The injuries are often particular to a specific phase of the throw and are well demonstrated with MR imaging. In this article, the authors review the phases of the throw, MR imaging techniques, and the MR appearances of the injuries associated with particular phases.

Width of high signal and extension posterior to biceps tendon as signs of superior labrum anterior to posterior tears on MRI and MR arthrography

OBJECTIVE

The purpose of our study was to determine the accuracy of two signs for superior labrum anterior to posterior (SLAP) tears: increased width of high signal between the superior labrum and glenoid, and high signal posterior to the biceps tendon.

MATERIALS AND METHODS

Forty-one patients with SLAP tears and 40 patients without a tear at surgery who had undergone MRI or MR arthrography were retrospectively evaluated. The MR studies were combined and interpreted in a blinded manner. The reviewers measured the width of high signal that extended to the articular surface on oblique coronal images and determined whether the high signal extended posterior to the biceps. A Student's t test was used to determine statistical significance between the means of the signal width.

RESULTS

High-signal width was greater in patients with a SLAP tear than in the control group on both MRI and MR arthrography (both p = 0.003). The sensitivity and specificity of at least 2.0 mm on MRI are 39% (11/28) and 89% (24/27) and at least 2.5 mm on MR arthrography are 46% (6/13) and 85% (11/13). The sensitivity and specificity of high signal posterior to the biceps are 54% (15/28) and 74% (20/27) on MRI and 69% (9/13) and 54% (7/13) on MR arthrography.

CONCLUSION

Increased width of high signal has a moderate specificity but a poor positive predictive value for distinguishing a SLAP tear from a normal recess. In addition, labral signal posterior to the biceps tendon is not rare in patients with no SLAP tear.

Shoulder MR arthrography: how, why, when

This article reviews current MR techniques for shoulder imaging, discusses advantages and disadvantages of each, and reviews the literature regarding sensitivity, specificity, and accuracy of MR arthrography versus nonenhanced MR in the evaluation of shoulder pathology, specifically, glenoid labral tears and rotator cuff tears.

MR imaging of shoulder instability injuries in the athlete

Lesions leading to glenohumeral instability may result from acute trauma, atraumatic laxity, or repetitive microtrauma. Athletic activities, especially overhead throwing, may lead to a series of lesions involving the stabilizing structures of the shoulder. The resultant injuries and pathomechanics leading to shoulder symptoms can be classified as primary disease, primary instability, acute traumatic instability, and posterosuperior impingment syndrome. MR imaging with or without intrarticular or intravenous injection of contrast material, along with clinical examination and stress testing, provides valuable preoperative assessment.

Horizontal component of partial-thickness tears of rotator cuff: imaging characteristics and comparison of ABER view with oblique coronal view at MR arthrography initial results

PURPOSE

To determine the characteristics of horizontal components of partial-thickness tears of the rotator cuff at magnetic resonance (MR) arthrography and to determine whether use of the abduction and external rotation (ABER) position improved detection of a horizontal component in partial-thickness tears.

MATERIALS AND METHODS

MR studies in 16 patients (mean age, 32 years) who had partial-thickness tear with a horizontal component were retrospectively evaluated. All 16 patients had undergone arthroscopic surgery. The depth and extent of the horizontal component were measured on MR images, and the presence or absence of articular surface tear was recorded. The characteristics of the horizontal component on ABER views were compared with those on oblique coronal views.

RESULTS

A horizontal component (24 lesions; one tendon involved in eight patients and two tendons involved in eight patients) was observed in 100% of the lesions on ABER views and in 21% of the lesions (n = 5) on oblique coronal images. The mean length of the horizontal components, measured on ABER views, was 1.9 cm (range, 0.6-4.5 cm). Thirteen (54%) of the 24 lesions were classified as grade I (<3 mm) in depth, four (17%) were classified as grade II (3-6 mm), and seven (29%) were classified as grade III (>6 mm). Articular separation sites with a flap lesion were visualized in 15 (62%) of 24 lesions on ABER views.

CONCLUSION

MR arthrography of the shoulder with patients in the ABER position may provide additional information in cases of partial-thickness tears of the rotator cuff with a horizontal component.

Magnetic resonance imaging of the upper extremity: advances in technique and application

Vast advances in technology have taken place in the field of radiology led by the introduction of magnetic resonance imaging. The added advantages of exquisite soft tissue contrast and multiplanar imaging capabilities have revolutionized the understanding of complex anatomic relationships and diagnoses. The current authors will focus on the introduction of new advances in magnetic resonance imaging of the upper extremity that may prove helpful in the diagnosis and treatment of upper extremity abnormalities.

Superior labral anterior posterior (SLAP) lesions of the glenoid labrum: reliability and accuracy of MR arthrography for diagnosis

PURPOSE

To determine the reliability and accuracy of magnetic resonance (MR) arthrography for the diagnosis of superior labral anterior posterior (SLAP) tears.

MATERIALS AND METHODS

The MR arthrograms in 80 patients who underwent arthroscopy and MR arthrography during a 54-month period were retrospectively reviewed. MR arthrograms were independently scored by three observers for the presence and type of SLAP lesion. Type I SLAP lesions were regarded as negative as they most often are not clinically relevant. Interobserver agreement for detection of SLAP lesions was calculated by using kappa coefficients. The differences in areas under the receiver operating characteristic (ROC) curves were assessed with a univariate z score test.

RESULTS

At arthroscopy, there were 25 SLAP tears: type II (n = 22), type III (n = 2), and type IV (n = 1). Sensitivity, specificity, and accuracy of each reader were 92%, 84%, and 86%; 92%, 82%, and 85%; and 84%, 69%, and 74%, respectively. Interobserver agreement for SLAP tears was substantial (kappa = 0.77) to moderate (kappa = 0.52, kappa = 0.44). The areas under the ROC curves for each reader were 0.94, 0.93, and 0.83, which were not significantly different.

CONCLUSION

MR arthrography of the shoulder is reliable and accurate for detection of SLAP tears.