Direct MR arthrography without image guidance: a practical guide, joint-by-joint

Direct MR arthrography (dMRA) is a fundamental technique in diagnosing pathology in major peripheral joints, allowing for precise evaluation of intra-articular structures. Although injection guidance is typically performed using imaging techniques such as ultrasound or fluoroscopy, puncture via anatomical landmarks may be useful in certain circumstances where it has been proven to be a safe and effective procedure. This paper describes the indications and injection technique of dMRA, joint by joint, focusing on the different technical details, from the most common locations, like the shoulder or hip, to those with more restricted clinical indications, such as the wrist, knee, elbow, or ankle. The most relevant anatomical landmarks are detailed for each joint, aiding in the intra-articular introduction of diluted contrast, highlighting the most accessible trajectories and structures to avoid when inserting the needle. Additionally, tips are provided to facilitate proper joint distension. With all this information, this paper aims to serve as a suitable reference guide for performing dMRA without image guidance if needed.

Value of MR arthrography for evaluation of children and adolescents with clinically suspected intraarticular cause of hip pain

PURPOSE

To evaluate the distribution of intra- and extraarticular MRI findings in children and adolescents with clinically suspected intraarticular cause of hip pain in order to assess the need for additional intraarticular contrast administration.

MATERIAL AND METHODS

Database was searched over a period of 34 months retrospectively for consecutive hip MR arthrography in young patients (8-17 years) with suspected intraarticular cause of hip or groin pain. Exclusion criteria were prior hip surgery, follow-up examination due to known intraarticular pathology, incomplete examination, qualitatively non-diagnostic examinations, and missing informed consent. Reports of fellowship-trained MSK radiologists were searched for intraarticular versus extraarticular findings explaining hip or groin pain.

RESULTS

Seventy patients (68% female; median age: 14.5 years; range:10.8-16.9 years) were analyzed. No reason for pain was found in 30 (42.9%) hips, extraarticular reasons in 20 (28.6%) cases, intraarticular in 14 (20.0%), and both (intra- and extraarticular) in 6 (8.6%) hips. Most common extraarticular reasons were apophysitis (14.3%), other bony stress reactions (12.9%), intramuscular edema (7%), tendinitis (5.7%), and trochanteric bursitis (4.3%). Labral pathology was the most common intraarticular finding (overall:34.3%; partial tear:15.7%, complete tear:15.7%), most frequent at the anterosuperior position (81.8%). Cartilage defects (1.4%), intraarticular neoplasia (1.4%), and tear of the femoral head ligament (2.8%) were rarely found. Synovitis and loose bodies were not observed. Cam-(37.1%) and pincer-configurations (47.1%) were common while hip dysplasia was rare (5.7%).

CONCLUSION

MRI in children and adolescents with hip pain should be done primarily without intraarticular contrast administration since most cases show an extraarticular pain reason or no diagnosis detectable with MRI.

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.

Trends in MR Arthrogram Utilization at a Tertiary Care Academic Center

The purpose is to evaluate the trends in MR arthrogram utilization at a tertiary care academic institution and to determine if there are factors that can be implicated in the utilization trends. Number of MR arthrograms of the shoulder, hip, and elbow from 2013-2020 at our institution were identified (n = 1882). Patient demographics including age, sex, sports participation, history of prior surgery, and physician referral were obtained. Descriptive statistics were performed to determine the prevalence of MR arthrograms. Linear regression analyses were performed to determine the relationship of time with prevalence of arthrograms. Chi-square tests and posthoc analyses with Bonferroni correction were used to assess if categorical variables were different between the years. There was overall decrease in the prevalence of MR arthrograms of the shoulder, hip, and elbow despite an increase in the overall MR volume during the study period. Linear regression models significantly predicated decrease in arthrogram prevalence with each passing year (P < 0.001). The percentage of orthopedic referrals for arthrograms in the hip (P = 0.002) and shoulder (P = < 0.001) decreased significantly towards the end of the study period. None of the other variables assessed were significant. At our tertiary care academic institution, arthrogram utilization has been drastically decreasing over the past 8 years. The percentage of orthopedic referrals for shoulder and hip arthrograms significantly decreased at the end of the study period.

Gadolinium injected concurrently with anesthetic can result in false-negative diagnostic intra-articular hip injections

PURPOSE

The purpose of this paper was to evaluate the response to intra-articular hip injections with and without concurrent gadolinium administration. Our secondary outcome was to compare post-operative outcomes between patients with an initial false-negative gadolinium-containing injection and a matched control group.

METHODS

Patients receiving a series of two hip diagnostic intra-articular injections (DIAI), the first with gadolinium for concurrent MRA and the second without gadolinium, were retrospectively identified. Pain response to DIAI, injectate volume, local anesthetic volume, inclusion of corticosteroids, and method of injection were compared between injections. False-negative injection was defined as < 50% pain relief with concurrent gadolinium, but ≥ 50% pain relief with subsequent anesthetic injection without gadolinium. False-negative injections in patients that ultimately underwent primary hip arthroscopy were identified from this cohort and matched in a 3:1 ratio to a control cohort to compare short-term post-operative single assessment numerical evaluation (SANE) outcomes.

RESULTS

Forty-three patients underwent a series of anesthetic injections with and without gadolinium and met inclusion and exclusion criteria. Pain response was significantly different in injections performed with and without gadolinium (18% vs. 81%; p < 0.001). There were significant differences in total injectate volume, local anesthetic volume, corticosteroid use, and method of injection between injections, but these variables were not correlated with pain response. Fifteen patients with false-negative responses to injection underwent primary hip arthroscopy and were matched in a 3:1 ratio to a control cohort. There was no difference in short-term post-operative SANE scores between the gadolinium-sensitive and control groups (81.6 vs. 80.0, n.s.).

CONCLUSION

Concurrent administration of intra-articular gadolinium with DIAI may result in a false-negative response to anesthetic. Additionally, in patients with initial false-negative DIAI with gadolinium, short-term post-operative outcomes after hip arthroscopy are similar to a matched cohort.

LEVEL OF EVIDENCE

Level III.

Radio-carpal wrist MR arthrography: comparison of ultrasound with fluoroscopy and palpation-guided injections

OBJECTIVE

To compare ultrasound- (US), fluoroscopy- (FL), and palpation-guided contrast injection techniques used for dorsal radio-carpal wrist MRA.

MATERIALS AND METHODS

Patients with chronic wrist pain were randomized as to which injection technique they underwent into three groups of 50 participants. Dorsal radio-carpal contrast injection was performed under US, FL guidance (one radiologist for each), or palpation guidance by an orthopedic surgeon. The three techniques were compared by procedure time, success rate, number of attempts needed, frequency and grade of extravasation, joint distension, and MRA image quality. Additionally, any change from baseline wrist pain was recorded using the visual analog scale (VAS) at five time points (immediately, 8 h, 24 h, 48 h, and 1 week) after injection.

RESULTS

One hundred and fifty patients (83 males and 67 females; mean age 29 ± 6.5 years) were included. Success rates for US- and FL-guided injections were 100%, while palpation-guided approach was significantly less successful (72%) (P = 0.02) with significantly more frequent extravasation (56%)(P < 0.001). US guidance was the least time-consuming (6.5 ± 1.6 min) compared to FL guidance (12.5 ± 1.9 min) and palpation guidance (8 ± 1.2 min) (all P < 0.001). The mean number of joint puncture attempts was significantly lower with imaging-guided techniques (1.1 ± 0.24 and 1.2 ± 0.4 for US and FL, P = 0.23) compared to palpation-guided one (1.6 ± 0.8) (P = 0.007). The largest increases in baseline-pain were 8-h post-injection, and US guidance was the least painful at all-time points (all P < 0.05). Joint distension and image quality were significantly better with imaging-guided techniques (P < 0.001 and P = 0.003).

CONCLUSIONS

US-guided radio-carpal injection is a less time-consuming, more tolerable, and successful radiation-free method when compared to FL guidance. Palpation-guided injections require multiple attempts to enter the joint with high failure rates and frequent extravasation.

Post-arthrogram synovitis: MRI and histopathologic findings

A 57-year-old patient developed severe, persistent pain following MR arthrography with iodinated contrast. MRI 1 week later showed synovitis which was new compared to the prior MRI. Arthroscopy showed severe synovitis. Histopathology showed synovitis characterized by lymphocytes, neutrophils, and necrosis. One out of 4 intraoperative cultures was positive, but ultimately believed to be due to contaminants. CRP normalized within 1 month. Repeat MRI 2 years later showed progressive degenerative findings, but no evidence of ongoing infection, or stigmata of previous infection. We believe this to be an unusually severe case of reactive synovitis. The purpose of the report is to add to knowledge of reactions to intra-articular contrast injection.

Correlation of magnetic resonance and arthroscopy in the diagnosis of shoulder injury

BACKGROUND

Advances in shoulder magnetic resonance imaging (MRI) and arthrography (MRA) have revolutionised musculoskeletal diagnosis and surgical planning. Despite this, the overall accuracy of MRI, with or without intra-articular contrast, can be variable.

METHODS

In this prospective non-randomised analysis, 200 participants (74.5% males) with suspected shoulder injuries underwent MRI (41.0%) or MRA followed by arthroscopy. A study specific proforma was developed to ensure consistency of reporting by radiologists and surgeons. The reports were compared to assess the predictive power of MRI/MRA. Specific assessment of rotator cuff tendon appearance, long head of biceps (LHB) tendon appearance, position and anchor, subacromial space, glenoid labrum and humeral cartilage grade were included.

RESULTS

Shoulder MRA demonstrated a higher agreement with arthroscopy than MRI for supraspinatus, infraspinatus and subscapularis tendon appearance (κ = 0.77 vs. κ = 0.61, κ = 0.55 vs. κ = 0.53 and κ = 0.58 vs. κ = 0.46 respectively). There were also superior agreement rates with MRA compared to MRI for LHB tendon appearance (κ = 0.70 vs. κ =0.54) and position (κ = 0.89 vs. κ = 0.72). As an overall assessor of shoulder pathology we found significantly higher total agreement scores when MRA was used (p = 0.002).

DISCUSSION

Whilst magnetic resonance imaging with arthrography is an extremely useful tool to assess underlying pathological shoulder states it does not confer 100% accuracy. In cases whereby this modality is inconclusive, an examination under anaesthesia and diagnostic arthroscopic assessment for the detection of intra-articular shoulder pathology may be considered.

Osteoarthritis of the hip: are degenerative tears of the acetabular labrum predictable from features on hip radiographs?

BACKGROUND

A common feature of hip arthritis is the presence of labra tears. Recent literature suggests against the use of magnetic resonance imaging (MRI) in patients aged >45 years for the assessment of hip pain related to arthritis.

PURPOSE

To determine if radiographic features of osteoarthritis detectable on routine hip radiographs are accurate and reliable surrogate markers of degenerative acetabular labral tears identified on MR arthrography (MRA) and corroborated during arthroscopy.

MATERIAL AND METHODS

A retrospective study involving 86 symptomatic patients (hip pain) with radiologic work-up included MRA and pelvic or hip radiographs that underwent hip arthroscopy within three months. Imaging characteristics assessed on hip radiographs include measurements of superior acetabular, femoral head osteophyte, cortical thickness of the femoral shaft, and minimum joint space as well as presence of subchondral sclerosis of the femoral head and acetabulum, femoral shaft buttressing, and grade of arthritis. Presence of a labral tear was determined by consensus between three readers as well as by surgical correlation. The Pearson's chi-squared and Fisher's exact tests were used to compare presence of labral tears with each radiographic feature.

RESULTS

Seventy-one patients (82.6%) had labral tears: 49 (69%) women and 22 (31%) men. Receiver operating characteristic analysis showed statistical significance (P<0.05) between presence of a labral tear and acetabular and femoral head osteophyte sizes but failed to demonstrate any significance regarding acetabular subchondral sclerosis, cortical thickness, buttressing, or minimum joint space.

CONCLUSIONS

Radiographic markers such as the acetabular and femoral head osteophyte sizes demonstrated statistical significance with the presence of labral tears.

Indirect Magnetic Resonance Arthrography May Help Avoid Second Look Arthroscopy for Assessment of Healing After Bucket Handle Medial Meniscus Repairs: A Prospective Clinico-Radiological Observational Study

OBJECTIVES

The objectives were: (1) to analyze the MRI healing rates of bucket-handle meniscus repair; (2) to compare the accuracy of assessment of meniscus healing for conventional MRI and Indirect Magnetic Resonance Arthrography (IMRA); and (3) to identify patients who may require second-look arthroscopy after meniscus repair.

METHODS

This is a prospective observational case series of thirty-seven patients with repaired bucket-handle medial meniscus tear with a minimum one year follow-up. Meniscus healing rates were assessed on direct MRI and IMRA using Henning's criteria. At the same time, patients' symptoms were evaluated according to Barrett's criteria and functional outcomes were recorded using International Knee Documentation Committee (IKDC) score, Knee Osteoarthritis and Outcomes Score (KOOS) and Tegner-Lysholm scores. A further clinical review was performed 18 months after the imaging to assess the evolution of symptoms.

RESULTS

At a mean of 22.3 ± 7.8 months after the meniscus repair, 56.7% patients showed complete healing and 40.5% patients demonstrated incomplete repair healing on IMRA. 52% patients with complete healing and 40% patients with incomplete healing demonstrated meniscus symptoms. At the second clinical review, 19% patients with complete healing and 20% patients with incomplete healing had meniscus symptoms. There was no co-relation between symptoms, PROMs and healing on MRI.

CONCLUSION

Indirect MR arthrography offers distinct advantages over direct MRI for assessment of meniscus healing, especially in symptomatic patients. Patient-reported outcome measures and symptomatology are not co-related with the healing status of the meniscus and they resolve in the majority on longer follow-up. A more conservative approach guided by IMRA to assess meniscus healing will avoid early re-operations.

Diagnostic Imaging of Ulnar Collateral Ligament Injury: A Systematic Review

BACKGROUND

Ulnar collateral ligament (UCL) injuries can be debilitating in overhead athletes. Accurate diagnosis is important; however, several imaging modalities are available for the assessment of UCL injuries.

PURPOSE

To provide a comprehensive review of published literature regarding the diagnostic capabilities of different imaging modalities for UCL tears.

METHODS

PubMed, Medline, and Embase were queried for peer-reviewed literature published between January 1947 and June 4, 2019, pertaining to diagnostic imaging of UCL tears. Articles assessing static and stress radiography, ultrasound, magnetic resonance imaging (MRI), MRI with arthrography (MRA), and computed tomography arthrography of the UCL were included. Studies were excluded if imaging results were not compared with intraoperative diagnosis, as intraoperative findings are generally considered the gold standard for diagnostic comparison. The articles were assessed per the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analyses) guidelines and reviewed with the Quality Assessment of Diagnostic Accuracy Studies, version 2 (QUADAS-2) assessment.

RESULTS

The literature search yielded 2478 articles, of which 15 were included in this review. Potential bias was noted in each QUADAS-2 subsection. Multiple studies demonstrate an association between UCL tears and osseous abnormalities identified on static radiographs; however, the use of static or nonstressed radiographs is not recommended for specific evaluation of UCL injuries. Conventional ultrasound was 81% sensitive and 91% specific, as compared with 96% and 81% for stress ultrasound, respectively. The sensitivity and specificity of MRI ranged from 57% to 100% and 89% to 100%. The sensitivity of computed tomography arthrography ranged from 63% to 86%. The sensitivity and specificity of MRA ranged from 81% to 100% and 91% to 100%.

CONCLUSION

Of the currently available imaging modalities, MRA provides the best combination of sensitivity and specificity of the evaluation of the UCL. Further research comparing ultrasound with MRA is needed.

Predictors of Pain and Discomfort Associated with CT Arthrography of the Shoulder

RATIONALE AND OBJECTIVES

The objective of this study was to investigate predictors of pain associated with computed tomographic arthrography of the shoulder.

MATERIALS AND METHODS

Before shoulder arthrography, all participants were assessed with the Hospital Anxiety and Depression Scale (HADS) and the World Health Organization Quality of Life Short Version Instrument (WHOQOL-BREF). The participants were nonrandomized into two groups: the anesthesia group, who underwent prior local infiltration anesthesia before shoulder arthrography, and the nonanesthesia group, who did not undergo prior local infiltration anesthesia. The pain levels at intraprocedure, at 1, 2, 6, and 12 hours, and at 1 and 2 days after injection were assessed by using a visual analog scale. Univariate and multivariate generalized linear model analyses were conducted.

RESULTS

Sixty participants in the anesthesia group and 60 participants in the nonanesthesia group were included. The pain level at intraprocedure (3.37 ± 1.94 in the anesthesia group and 3.20 ± 1.34 in the nonanesthesia group) was the highest of the whole pain course. The psychological domain (P = .0013) of WHOQOL-BREF, gender (P = .042), body mass index (P = .0001), and the total number of reinsertion and redirection of needle (P< .0001) were independent predictors of arthrography-related pain.

CONCLUSIONS

The pain associated with shoulder computed tomographic arthrography depends on the psychological domain of WHOQOL-BREF, gender, body mass index, and the total number of reinsertion and redirection of needle.

Detour sign in the diagnosis of subluxation of the long head of the biceps tendon with arthroscopic correlation

OBJECTIVE

To determine whether detection of the detour sign via MRI indicates subluxation of the long head of the biceps tendon (SLBT) in the shoulder joint and to investigate the association of SLBT with the degeneration of the long head of the biceps tendon (LBT) and rotator cuff tears.

METHODS

This retrospective study included 65 patients with shoulder pain who underwent shoulder MRI and arthroscopic surgery. When axial images revealed that the LBT was displaced over the inner rim of the bicipital groove with some remaining contact with the groove (Criterion 1), or demonstrated a "detour sign" of the biceps tendon (Criterion 2), the lesion was diagnosed as an SLBT. Shoulder arthroscopy was used as the reference standard.

RESULTS

Arthroscopy identified SLBT in 18 patients. When the MRI diagnosis was based on Criterion 1 alone, SLBT was diagnosed with a sensitivity of 44.4-55.6% and 75.4-80% accuracy. However, when the MRI diagnosis was based on Criteria 1 plus 2, SLBT was diagnosed with a sensitivity of 83.3-94.4% and 78.5-81.5% accuracy. There was a significant difference (p < 0.05) in the diagnostic sensitivity of Criteria 1 and 2.

CONCLUSION

The detour sign based on axial MRI may be regarded an additional useful anatomical feature that improves the diagnostic performance of MRI in the identification of SLBT lesions. Advances in knowledge: Recognition of the detour sign may enhance the diagnostic performance of the conventional MRI protocol over the MR arthrography protocol for SLBT.

Comparison of magnetic resonance arthrography with arthroscopy for imaging of shoulder injuries: retrospective study

BACKGROUND Arthroscopy is the established 'gold standard' diagnostic investigation for detection of shoulder disorders. We aimed to compare the diagnostic accuracy of arthroscopy with magnetic resonance arthrography (MRA) for detection of shoulder disorders. METHODS Patients who underwent arthroscopy by a single surgeon and preoperative MRA between February 2011 and March 2012 for shoulder instability were identified. MRAs were reported by experienced musculoskeletal radiologists. Labral tears, anterior labral tears, superior labral anterior posterior (SLAP) lesions, posterior labral tears, rotator-cuff tears (RCTs), osteoarthritis, loose bodies and Hill-Sachs lesions were identified. Sensitivity, specificity, positive predictive value and negative predictive value, positive likelihood ratio and negative likelihood ratio were calculated. RESULTS A total of 194 patients were identified. The sensitivity and specificity for anterior labral tears was 0.60 and 0.92, SLAP lesions was 0.75 and 0.81, posterior labral tears was 0.57 and 0.96, any labral tear was 0.87 and 0.76, Hill-Sachs lesions was 0.91 and 0.91, RCTs was 0.71 and 0.86, osteoarthritis was 0.72 and 0.95, and loose bodies was 0.22 and 0.96, respectively. The positive predictive value and negative predictive value for anterior labral tears were 0.88 and 0.71, SLAP lesions was 0.64 and 0.88, posterior labral tears was 0.74 and 0.45, any labral tear was 0.89 and 0.71, Hill-Sachs lesions was 0.66 and 0.98, RCTs was 0.47 and 0.95, osteoarthritis was 0.70 and 0.95, and loose bodies was 0.27 and 0.95, respectively. CONCLUSIONS MRA has high diagnostic accuracy for labral tears and Hill-Sachs lesions, but whether MRA should be the first-line imaging modality is controversial.

Magnetic Resonance Arthrogram Referrals by Subspecialist and Non-Subspecialist Orthopaedic Surgeons: What are the Findings?

Background:

Although subspecialist orthopaedic surgeons usually request Magnetic Resonance Arthrogram (MRA) examinations, some orthopaedic surgeons may request this examination for a body part that is different from their subspecialty. The purpose of the study is to compare the MRA and the clinical findings in the subspecialist and non-subspecialist groups.

Method:

Retrospective analysis of MRA examinations over a 6-month period. Findings were compared with the clinical information.

Results:

There were 144 examinations (69 shoulder, 42 wrist and 33 hip). 85% of these were subspecialist referrals; 60% of them showed findings compatible with the clinical diagnosis. 15% of the MRA examinations were non-subspecialist referrals; 52% of them correlated with the clinical findings.

Overall, clinical information agreed with MRA findings for shoulder labral tears, hip labral tears and wrist triangular fibrocartilage complex tears in 63.3%, 64.5% and 61.5% respectively. The subspecialist group were more accurate than the non-subspecialist group in diagnosing hip labral tears (68% vs. 50%) and triangular fibrocartilage complex tears (62.5% vs. 50%). On the contrary, shoulder MRA and clinical findings correlated better in the non-subspecialist group (77.8%) compared to the subspecialist group (63.3%). However, the small number of requests generated by the non-subspecialist group may affect the results. Suspected scapholunate ligament injury showed low correlation with MRA at 26.7% (33.3% in the subspecialist group and 0% in the non-subspecialist group).

Conclusion:

Generally, the clinical findings are more accurate in the subspecialist referrals when compared to MRA findings and therefore a subspecialist referral is preferred. The low agreement between clinically suspected scapholunate ligament injuries and wrist MRA probably reflects the relative difficulty in establishing this diagnosis clinically.

Magnetic resonance arthrography and the prevalence of acetabular labral tears in patients 50 years of age and older

OBJECTIVE

Arthroscopy for acetabular labral tears has minimal impact on pain and function in older patients, especially in the setting of concomitant osteoarthritis. Still, many physicians seek this diagnosis with MR arthrography. Our purpose is to assess the frequency of acetabular labral tears in older patients with hip pain and correlate likelihood of labral pathology with severity of osteoarthritis as visualized on conventional radiograph.

MATERIALS AND METHODS

From 2004 to 2013, 208 hip MRI arthrograms and corresponding radiographs on patients aged 50 years and older were identified. Age, gender, grade and location of labral tear, alpha angle, Tönnis grade, and joint space width were documented. Labral tears and alpha angle were identified and measured on MR arthrogram. Tönnis grade and joint space width were measured on radiographs.

RESULTS AND CONCLUSIONS

On MR arthrography, true labral tearing was identified in 73 % of patients. There was some degree of labral pathology in 93.3 % of patients, and this increased to 100 % in patients with moderate to severe osteoarthritis, as defined by Tönnis grade 2-3 or joint space width ≤ 2 mm. There were no statistically significant correlations between labral tear grade and Tönnis grade or joint space width. Given the high frequency of labral pathology and the questionable efficacy of arthroscopic surgical intervention in older patients, MR arthrography should be primarily for those with minimal arthritis on radiograph and potential to benefit from surgery. If further imaging beyond radiographs is necessary in these patients, standard MRI may be a more appropriate imaging tool.

MRI for the preoperative evaluation of femoroacetabular impingement

Femoroacetabular impingement (FAI) refers to a condition characterized by impingement of the femoral head–neck junction against the acetabular rim, often due to underlying osseous and/or soft tissue morphological abnormalities. It is a common cause of hip pain and limited range of motion in young and middle-aged adults. Hip preservation surgery aims to correct the morphological variants seen in FAI, thereby relieving pain and improving function, and potentially preventing early osteoarthritis. The purpose of this article is to review the mechanisms of chondral and labral injury in FAI to facilitate an understanding of patterns of chondrolabral injury seen on MRI. Preoperative MRI evaluation of FAI should include assessment of osseous morphologic abnormalities, labral tears, cartilage status, and other associated compensatory injuries of the pelvis. As advanced chondral wear is the major relative contraindication for hip preservation surgery, MRI is useful in the selection of patients likely to benefit from surgery.

Teaching points

• The most common anatomical osseous abnormalities predisposing to FAI include cam and pincer lesions.

• Morphological abnormalities, labral lesions, and cartilage status should be assessed.

• In cam impingement, chondral wear most commonly occurs anterosuperiorly.

• Pre-existing advanced osteoarthritis is the strongest predictor of poor outcomes after FAI surgery.

• Injury to muscles and tendons or other pelvic structures can coexist with FAI.

Postprocedural pain in shoulder arthrography: differences between using preservative-free normal saline and normal saline with benzyl alcohol as an intraarticular contrast diluent

OBJECTIVE

The purpose of this study was to prospectively evaluate the effect of benzyl alcohol, a common preservative in normal saline, on postprocedural pain after intraarticular injection for direct shoulder MR arthrography.

SUBJECTS AND METHODS

From April 2011 through January 2013, 138 patients underwent direct shoulder MR arthrography. Using the Wong-Baker Faces Pain Scale, patients were asked to report their shoulder pain level immediately before and immediately after the procedure and then were contacted by telephone 6, 24, and 48 hours after the procedure. Fourteen patients did not receive the prescribed amount of contrast agent for diagnostic reasons or did not complete follow-up. Sixty-two patients received an intraarticular solution including preservative-free normal saline (control group) and 62 patients received an intraarticular solution including normal saline with 0.9% benzyl alcohol as a contrast diluent (test group). Patients were randomized as to which intraarticular diluent they received. Fluoroscopic and MR images were reviewed for extracapsular contrast agent administration or extravasation, full-thickness rotator cuff tears, and adhesive capsulitis. The effect of preservative versus control on pain level was estimated with multiple regression, which included time after procedure as the covariate and accounted for repeated measures over patients.

RESULTS

Pain scale scores were significantly (p = 0.0382) higher (0.79 units; 95% CI, 0.034-1.154) with benzyl alcohol preservative compared with control (saline). In both study arms, the pain scale scores decreased slightly after the procedure, increased by roughly 1 unit over baseline for the test group and 0.3 unit over baseline for the control group by 6 hours after the procedure, were 0.50 unit over baseline for the test group and 0.12 unit over baseline for the control group at 24 hours, then fell to be slightly greater than baseline at 48 hours with benzyl alcohol and slightly less than baseline without benzyl alcohol. These trends over time were highly significant (p < 0.0001).

CONCLUSION

Shoulder arthrography is often associated with postprocedural discomfort that begins immediately after the procedure and resolves by 48 hours. There is significantly increased patient discomfort at 6 and 48 hours when using normal saline preserved with benzyl alcohol as a diluent compared with using normal saline without preservative as a diluent.

[Detection of intrinsic ligament and TFCC lesions of the wrist. Direct versus indirect MRI arthrography]

BACKGROUND

The purpose of this study was to validate the diagnostic value of direct magnetic resonance imaging (dMRI) arthrography and indirect MRI (iMRI) arthrography concerning intrinsic ligament injuries and tears of the triangular fibrocartilage complex (TFCC).

PATIENTS AND METHODS

A randomized prospective trial was conducted with patients who presented with wrist pain potentially due to carpal lesions and 10 patients aged 19-60 years (3 female and 7 male) were included. Between the clinical examination and the diagnostic and therapeutic arthroscopy, dMRI and iMRI arthrography were performed for the diagnostics of injuries of the intrinsic ligaments or the TFCC. The results of dMRI and iMRI arthrography were evaluated by two radiologists blinded to the injuries of the patients and a consensus was reached. The results were compared with the findings obtained by arthroscopy.

RESULTS

In the arthroscopy five lesions of the scapholunate ligament (SL), one of the lunotriquetral ligament (LT) and seven of the TFCC were identified. The sensitivity of iMRI and dMRI for carpal ligament lesions (SL and LT) was low (50 %) whereas the specificity was high (93 %). For injuries of the TFCC the sensitivity (up to 100 %) and the specificity (100 %) were both excellent. The area under the curve (AUC) in the receiver operating characteristics (ROC) analysis was high for TFCC lesions in both dMRI and iMRI arthrography.

CONCLUSION

Indirect MRI arthrography is a suitable method for detection of injuries of the TFCC and intrinsic ligaments of the wrist with good sensitivity and specificity. Despite the low number of patients the results of this study showed that there were no essential differences between dMRI and iMRI arthrography with respect to the diagnostic value for carpal injuries of the wrist.

MRI of the hip for the evaluation of femoroacetabular impingement; past, present, and future

The concept of femoroacetabular impingement (FAI) has, in a relatively short time, come to the forefront of orthopedic imaging. In just a few short years MRI findings that were in the past ascribed to degenerative change, normal variation, or other pathologies must now be described and included in radiology reports, as they have been shown, or are suspected to be related to, FAI. Crucial questions have come up in this time, including: what is the relationship of bony morphology to subsequent cartilage and labral damage, and most importantly, how is this morphology related to the development of osteoarthritis? In this review, we attempt to place a historical perspective on the controversy, provide guidelines for interpretation of MRI examinations of patients with suspected FAI, and offer a glimpse into the future of MRI of this complex condition.

Chondrolysis of the Hip following Septic Arthritis: A Rare Complication of Magnetic Resonance Arthrography

Magnetic resonance arthrography (MRA) is commonly used to detect labral tears of the hip. Complications of MRA are unusual and include minor reactions such as chemical synovitis and urticaria. This paper presents a rapidly progressive chondrolysis of the hip in a young patient after arthrography. The patient had suffered from acute septic arthritis and was treated by emergent arthroscopic surgery followed by appropriate antibiotics. At 18 months of followup, there were no signs of active infection but evidence of joint chondrolysis. Magnetic resonance arthrography (MRA) of the hip is an invasive procedure and should therefore be recommended judiciously. Post-MRA pain is common but often mild and temporary, while post-MRA joint infection is rare; nevertheless, severe joint pain and limitation should raise suspicion for septic hip.

MR arthrography of the shoulder: tolerance evaluation of four different injection techniques

OBJECTIVE

We sought to prospectively evaluate patients' pain perception and technical success of four different arthrographic techniques for shoulder MR arthrography.

MATERIALS AND METHODS

A total of 125 consecutive patients were referred for shoulder MR arthrography. The patients were randomly injected under fluoroscopic guidance (n(1) = 37), with CT guidance using an anterior (n(2) = 29) or a posterior approach (n(3) = 32) and with ultrasound guidance (n(4) = 27). For each patient, absolute periprocedural pain on a numerical rating pain scale (0 = "no pain", 10 = "intolerable pain"), technical success of the method used, and reason for referral were recorded.

RESULTS

The technical success rate was 100% for all injection methods. The results regarding absolute periprocedural pain were as follows: fluoroscopic guidance showed a mean pain of 4.05 ± 1.24, CT anterior guidance demonstrated a mean pain of 3.87 ± 0.95, CT posterior guidance showed a mean pain of 1.59 ± 0.81, and ultrasound guidance a mean pain of 3.63 ± 1.12. A significant difference (p < .05) was observed for the posterior route under CT guidance. The mean pain level was significantly higher for older (> 51 year) female patients.

CONCLUSIONS

No differences were found for the technical success rate of the aforementioned techniques. A CT-guided posterior approach seems to be a more comfortable method for the patient.

Validity of noncontrast magnetic resonance imaging in diagnosing superior labrum anterior-posterior tears

BACKGROUND

The biceps labral complex has received much interest in recent years as a source of shoulder pain. Magnetic resonance imaging (MRI) is the imaging modality of choice for those patients with a suspected superior labrum anterior-posterior (SLAP) tear. The goal of this study was to look at the accuracy of MRI without arthrography to correctly identify SLAP tears.

METHODS

The study had a prospective, case-based, case-control design. Participants were consecutive patients seen at an orthopaedic outpatient clinic who received an MRI scan as part of their diagnostic cycle. All patients were aged at least 18 years, with various shoulder dysfunctions (impingement, rotator cuff tear, and so on) that were evaluated during a routine clinical evaluation. Arthroscopic surgery was performed as the reference standard for a SLAP lesion.

RESULTS

Seventy-seven patients were evaluated during arthroscopic surgery. The pretest probability of a SLAP lesion-only diagnosis was 18.2%, and for a SLAP lesion with or without a concomitant diagnosis, the pretest probability was 66.2%. In both cases, use of MRI led to post-test probability values that were worse when a positive finding was identified on the MRI scan.

DISCUSSION

The results of this study suggest that SLAP tears are often incorrectly diagnosed based on MRI evaluation, with MRI providing a high level of sensitivity and low level of specificity. On the basis of the results of this study, conventional MRI is not a suitable test to accurately evaluate the biceps labral complex for the presence of a SLAP tear.

Indirect magnetic resonance arthrography of the shoulder; a reliable diagnostic tool for investigation of suspected labral pathology

PURPOSE

Indirect magnetic resonance arthrography (I-MRA) confers significant logistical advantages over direct MRA and does not require articular injection. In this study, we determined the diagnostic performance of I-MRA in relation to conventional MRI and arthroscopy or surgery in detecting tears of the glenoid labrum, including Bankart lesions and superior labral antero-posterior (SLAP) tears in a standard clinical setting.

PATIENTS AND METHODS

Ninety-one symptomatic patients underwent conventional MRI and I-MRA of the affected shoulder, followed by either arthroscopy or open surgery. The scans were interpreted independently by two experienced radiology consultants with a special interest in musculoskeletal radiology. Using the surgical findings as the standard of reference, sensitivity, specificity, and diagnostic accuracy of conventional non-contrast MRI and I-MRA in the detection of labral tears were calculated.

RESULTS

The sensitivity of I-MRA was 95 and 97 %, respectively, for two radiologists as opposed to 79 and 83 % for conventional MRI. For both radiologists, the specificity of I-MRA, as well as MRI, was 91 % for detection of labral tears of all types. Accuracy of diagnosis was 93 and 95 %, respectively, for two radiologists with indirect MRA, compared to 84 and 86 % with non-contrast MRI.

CONCLUSIONS

This retrospective study shows that I-MRA is a highly accurate and sensitive method for the detection of labral tears. The data obtained supports the use of I-MRA as standard practice in patients with shoulder instability due to suspected labral pathology where further investigative imaging is indicated.

Technical update on magnetic resonance imaging of the shoulder

Improvement in both hardware and software has opened up new opportunities in magnetic resonance (MR) imaging of the shoulder. MR imaging at 3-T has become a reality, with the prospect of 7-T imaging on the horizon. The art of MR arthrography continues to improve, aided by the use of novel imaging positions. New techniques for three-dimensional imaging, the reduction of metal artifact, and biochemical imaging of cartilage hold great promise.