MR Arthrography of the Glenohumeral Joint: Modified Posterior Approach without Imaging Guidance

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.

Direct MR arthrography of the hip joint: anterior approach without imaging guidance

PURPOSE

The purpose of this study is to describe the anterior injection approach, with anatomical landmark guidance, for direct MR arthrography (dMRA) of the hip joint, and to evaluate the effectiveness in joint distension and the security of the technique.

MATERIAL AND METHODS

Retrospective review of hip dMRAs was conducted on patients with suspected intra-articular pathology from two MR outpatient centers, performed by two radiologists with 25 and 5 years of experience, respectively. The analysis included assessing the presence of intra-articular contrast material (gadolinium-based solution), the number of injections performed, the degree of joint distension, and the degree of contrast extravasation. A multi-variant analysis was carried out to determine if the procedure success depend on any of the demographic variants or on the radiologist experience. Additionally, the presence of immediate and medium-term post-puncture complications was evaluated.

RESULTS

One hundred patients with 104 hip dMRA were included; 60 were men, with mean age of 38 years (16-63 years). Contrast material was successfully introduced intra-articularly in 100% of patients, being necessary a second puncture only in 6% of procedures. The capsular distension was considered optimal for diagnosis in 97% of cases. Different degrees of contrast extravasation were found in 30% of dMRA. There was no statistically significant relationship observed between patient variables and the performance of dMRA, nor did it show any correlation with the experience of the radiologists. No puncture-derived complications were found.

CONCLUSION

Hip dMRA through anterior injection guided by anatomical references is an effective and safe alternative for patients with suspected intra-articular pathology.

Divalent Manganese Complexes as Potential Replacements for Gadolinium-Based Contrast Agents

ABSTRACT

Recent safety concerns surrounding the use of gadolinium-based contrast agents (GBCAs) have spurred research into identifying alternatives to GBCAs for use with magnetic resonance imaging. This review summarizes the molecular and pharmaceutical properties of a GBCA replacement and how these may be achieved. Complexes based on high-spin, divalent manganese (Mn 2+ ) have shown promise as general purpose and liver-specific contrast agents. A detailed description of the complex Mn-PyC3A is provided, describing its physicochemical properties, its behavior in different animal models, and how it compares with GBCAs. The review points out that, although there are parallels with GBCAs in how the chemical properties of Mn 2+ complexes can predict in vivo behavior, there are also marked differences between Mn 2+ complexes and GBCAs.

Squishing sound heard following an intra-articular shoulder injection with fluid and air is associated with higher efficacy: A retrospective analysis

BACKGROUND

Accuracy of blind intra-articular injections for the shoulder is rather low. It is unclear whether accurate injections for capsulitis of the shoulder are more effective than inaccurate injections.

OBJECTIVE

It has been hypothesized that a squishing sound following an intra-articular injection with a mixture of air and fluid means that the injection was accurately placed and that the efficacy of accurately placed injections is greater than that of inaccurate injections. The aim of the present study was to test the hypothesis that a squishing sound following an injection predicts a better clinical result.

METHODS

Files were selected of patients with capsulitis of the shoulder, who were treated with an intra-articular injection containing a mixture of triamcinolone, lidocaine, and air. After the injection, the shoulder was moved to determine whether a squishing sound could be produced. Efficacy was measured after two weeks according to the Patient Global Impression of Change scale. Differences in efficacy between injections with and without a squishing sound were expressed as an odds ratio.

RESULTS

Sixty-one patients were selected. Squishing was heard after 47 injections (77%). Two weeks after the injection, a positive outcome was reported by 49 patients (80%). When squishing was heard, the effect was positive in 42 of the 47 patients (89%) and when no squishing was heard, the effect was positive in 7 of the 14 patients (50%). The odds ratio was 8.4 (95% CI 2.1-34.0; p= 0.003).

CONCLUSION

Efficacy of injections with a mixture of triamcinolone, lidocaine, and air for capsulitis of the shoulder is significantly greater when a squishing sound was heard after the injection. We hypothesize that squishing is related to accuracy and accuracy to efficacy. A future study with X-ray arthrography is needed to verify both hypotheses.

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

BACKGROUND

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

PURPOSE

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

STUDY TYPE

Prospective.

SUBJECTS

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

FIELD STRENGTH/SEQUENCE

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

ASSESSMENT

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

STATISTICAL TESTS

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

RESULTS

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

DATA CONCLUSION

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

A comparison of ultrasound-guided rotator interval and posterior glenohumeral injection techniques for MR shoulder arthrography

PURPOSE

The aim of this prospective, randomized study was to compare the performance of a rotator interval approach with the posterior glenohumeral approach for ultrasound-guided contrast injection prior to MR shoulder arthrography.

METHOD

This study was approved by the institutional review board. One hundred and twenty consecutive patients referred for MR shoulder arthrography were randomized into four groups: rotator interval approach in-plane (n = 30); rotator interval approach out-of-plane (n = 30); posterior approach in-plane (n = 30); and posterior approach out-of plane (n = 30). Outcome measures included procedure time, number of injection attempts, patient-reported pain score (0-10), and radiologist-reported technical difficulty (0-10). MR arthrograms were assessed for adequacy of joint distension, diagnostic utility, and extra-capsular contrast leakage.

RESULTS

All 120 patients had a successful ultrasound-guided injection with adequate joint distension and diagnostic utility for MR arthrography. In-plane needle guidance was less technically demanding, quicker, required fewer injection attempts, and had a lower frequency of contrast leakage than out-of-plane needle guidance. The posterior glenohumeral approach was less technically demanding though had a higher frequency of contrast leakage and caused more patient discomfort than the rotator interval approach.

CONCLUSION

For ultrasound-guided shoulder joint injection, an in-plane approach is preferable. The posterior glenohumeral approach is less technically demanding though causes more patients discomfort than the rotator interval approach possibly due to the longer needle path.

Trans-coracoacromial Ligament Glenohumeral Injection With Arthroscopic Confirmation

PURPOSE

To arthroscopically evaluate the trans-coracoacromial ligament glenohumeral (GH) injection technique by understanding intra-articular needle-tip placement and potential misplacement and complications.

METHODS

The technique relies on the palpation of 3 bony landmarks: anterolateral corner of the acromion, superolateral border of the coracoid tip, and curved depression of the distal clavicle. The skin entry site lies on the line connecting the curved depression of the distal clavicle and superolateral border of the coracoid tip, two-thirds of the way from the former and one-third of the way from the latter. The direction of the needle is perpendicular to the triangle formed by the 3 bony landmarks. The technique is used to insufflate the GH joint at the start of shoulder arthroscopy procedures with patients in the beach-chair position. Saline solution is injected, and the position of the needle tip in the GH joint is evaluated arthroscopically. An injection is considered successful if saline solution can be injected and the needle tip can be visualized intra-articularly.

RESULTS

This study enrolled 195 patients undergoing shoulder arthroscopy. Successful needle placement in the GH joint occurred in 179 patients (91.8%); placement occurred through the rotator interval in 122 of these, adjacent or through the long head of the biceps tendon in 41, through the upper subscapularis or anterior supraspinatus in 13, and through the anterior labrum in 3. Regarding the 16 failures (8.2%), the needle position did not allow saline solution to be injected because of high resistance in 3 patients whereas the needle tip was not visualized in 13. The needle tip was presumed to rest within the subscapularis muscle or tendon or the labrum in 10 failed injections.

CONCLUSIONS

The trans-coracoacromial ligament injection technique showed a high success rate (91.8%) in anesthetized patients about to undergo arthroscopy, whereas the failed injections mainly occurred because the needle was inserted into the subscapularis or labrum. This technique can be used for awake patients with different diagnoses in multiple settings.

LEVEL OF EVIDENCE

Level IV, diagnostic study.

Tumor Contrast Enhancement and Whole-Body Elimination of the Manganese-Based Magnetic Resonance Imaging Contrast Agent Mn-PyC3A

OBJECTIVES

The goals of this study were to compare the efficacy of the new manganese-based magnetic resonance imaging (MRI) contrast agent Mn-PyC3A to the commercial gadolinium-based agents Gd-DOTA and to Gd-EOB-DTPA to detect tumors in murine models of breast cancer and metastatic liver disease, respectively, and to quantify the fractional excretion and elimination of Mn-PyC3A in rats.

METHODS

T1-weighted contrast-enhanced MRI with 0.1 mmol/kg Mn-PyC3A was compared with 0.1 mmol/kg Gd-DOTA in a breast cancer mouse model (n = 8) and to 0.025 mmol/kg Gd-EOB-DTPA in a liver metastasis mouse model (n = 6). The fractional excretion, 1-day biodistribution, and 7-day biodistribution in rats after injection of 2.0 mmol/kg [Mn]Mn-PyC3A or Gd-DOTA were quantified by Mn gamma counting or Gd elemental analysis. Imaging data were compared with a paired t test; biodistribution data were compared with an unpaired t test.

RESULTS

The postinjection-preinjection increases in tumor-to-muscle contrast-to-noise ratio (ΔCNR) 3 minutes after injection of Mn-PyC3A and Gd-DOTA (mean ± standard deviation) were 17 ± 3.8 and 20 ± 4.4, respectively (P = 0.34). Liver-to-tumor ΔCNR values at 8 minutes postinjection of Mn-PyC3A and Gd-EOB-DTPA were 28 ± 9.0 and 48 ± 23, respectively (P = 0.11). Mn-PyC3A is eliminated with 85% into the urine and 15% into the feces after administration to rats. The percentage of the injected doses (%ID) of Mn and Gd recovered in tissues after 1 day were 0.32 ± 0.12 and 0.57 ± 0.12, respectively (P = 0.0030), and after 7 days were 0.058 ± 0.051 and 0.19 ± 0.052, respectively (P < 0.0001).

CONCLUSIONS

Mn-PyC3A provides comparable tumor contrast enhancement to Gd-DOTA in a mouse breast cancer model and is more completely eliminated than Gd-DOTA; partial hepatobiliary elimination of Mn-PyC3A enables conspicuous delayed phase visualization of liver metastases.

Clinical indications for image-guided interventional procedures in the musculoskeletal system: a Delphi-based consensus paper from the European Society of Musculoskeletal Radiology (ESSR)-part I, shoulder

BACKGROUND

Image-guided interventional procedures around the shoulder are commonly performed in clinical practice, although evidence regarding their effectiveness is scarce. We report the results of a Delphi method review of evidence on literature published on image-guided interventional procedures around the shoulder with a list of clinical indications.

METHODS

Forty-five experts in image-guided musculoskeletal procedures from the ESSR participated in a consensus study using the Delphic method. Peer-reviewed papers regarding interventional procedures around the shoulder up to September 2018 were scored according to the Oxford Centre for Evidence-based Medicine levels of evidence. Statements on clinical indications were constructed. Consensus was considered as strong if more than 95% of experts agreed and as broad if more than 80% agreed.

RESULTS

A total of 20 statements were drafted, and 5 reached the highest level of evidence. There were 10 statements about tendon procedures, 6 about intra-articular procedures, and 4 about intrabursal injections. Strong consensus was obtained in 16 of them (80%), while 4 received broad consensus (20%).

CONCLUSIONS

Literature evidence on image-guided interventional procedures around the shoulder is limited. A strong consensus has been reached for 80% of statements. The ESSR recommends further research to potentially influence treatment options, patient outcomes, and social impact.

KEY POINTS

• Expert consensus produced a list of 20 evidence-based statements on clinical indications of image-guided interventional procedures around the shoulder. • The highest level of evidence was reached for five statements. • Strong consensus was obtained for 16 statements (80%), while 4 received broad consensus (20%).

The biological fate of gadolinium-based MRI contrast agents: a call to action for bioinorganic chemists

Gadolinium-based contrast agents (GBCAs) are widely used with clinical magnetic resonance imaging (MRI), and 10 s of millions of doses of GBCAs are administered annually worldwide. GBCAs are hydrophilic, thermodynamically stable and kinetically inert gadolinium chelates. In clinical MRI, 5-10 millimoles of Gd ion is administered intravenously and the GBCA is rapidly eliminated intact primarily through the kidneys into the urine. It is now well-established that the Gd3+ ion, in some form(s), is partially retained in vivo. In patients with advanced kidney disease, there is an association of Gd retention with nephrogenic systemic fibrosis (NSF) disease. However Gd is also retained in the brain, bone, skin, and other tissues in patients with normal renal function, and the presence of Gd can persist months to years after the last administration of a GBCA. Regulatory agencies are restricting the use of specific GBCAs and inviting health care professionals to evaluate the risk/benefit ratio prior to using GBCAs. Despite the growing number of studies investigating this issue both in animals and humans, the biological distribution and the chemical speciation of the residual gadolinium are not fully understood. Is the GBCA retained in its intact form? Is the Gd3+ ion dissociated from its chelator, and if so, what is its chemical form? Here we discuss the current state of knowledge regarding the issue of Gd retention and describe the analytical and spectroscopic methods that can be used to investigate the Gd speciation. Many of the physical methods that could be brought to bear on this problem are in the domain of bioinorganic chemistry and we hope that this review will serve to inspire this community to take up this important problem.

Manganese-Based Contrast Agents for Magnetic Resonance Imaging of Liver Tumors: Structure-Activity Relationships and Lead Candidate Evaluation

Gd-based MRI contrast agents (GBCAs) have come under intense regulatory scrutiny due to concerns of Gd retention and delayed toxicity. Three GBCAs comprising acyclic Gd chelates, the class of GBCA most prone to Gd release, are no longer marketed in Europe. Of particular concern are the acyclic chelates that remain available for liver scans, where there is an unmet diagnostic need and no replacement technology. To address this concern, we evaluated our previously reported Mn-based MRI contrast agent, Mn-PyC3A, and nine newly synthesized derivatives as liver specific MRI contrast agents. Within this focused library the transient liver uptake and rate of blood clearance are directly correlated with log P. The complex Mn-PyC3A-3-OBn emerged as the lead candidate due to a combination of high relaxivity, rapid blood clearance, and avid hepatocellular uptake. Mn-PyC3A-3-OBn rendered liver tumors conspicuously hypo-intense in a murine model and is wholly eliminated within 24 h of injection.

Transcoracoacromial Ligament Glenohumeral Injection Technique: Accuracy of 116 Injections in Idiopathic Adhesive Capsulitis

PURPOSE

To describe a transcoracoacromial ligament glenohumeral injection technique that does not require radiographic guidance and to explore the accuracy of this injection technique in patients with idiopathic adhesive capsulitis.

METHODS

From February 2015 to April 2017, 89 consecutive patients (116 injections) with idiopathic adhesive capsulitis were included in the study. All of them received unguided glenohumeral injection via the transcoracoacromial ligament technique, and postprocedural fluoroscopic images were used to determine accuracy. The anterolateral corner of acromion, the superior lateral border of coracoid tip, and the curved depression of distal clavicle were identified. The needle entry site was located at the trisection point between the distal third and middle third of the superior lateral border of coracoid tip-curved depression of the distal clavicle line; needle trajectory was perpendicular to the plane formed by the 3 points, and the needle was advanced toward the humeral head. An injection was rated a success if the first fluoroscopic picture showed intra-articular contrast; it was rated a failure if contrast was not intra-articular or the needle needed to be redirected more than 2 times.

RESULTS

Out of 116 injections, 111 (95.7%) were successful. For 5 failed injections, there was 1 shoulder with more than 3 redirections and 4 shoulders with no intra-articular contrast (the needle hit the coracoid process in 1 shoulder, the needle rested in the anterior glenoid labrum in 2 shoulders, and the needle was inserted into the subscapularis in 1 shoulder).

CONCLUSIONS

The transcoracoacromial ligament glenohumeral injection technique is highly accurate and reproducible in patients with idiopathic adhesive capsulitis.

LEVEL OF EVIDENCE

Level IV, therapeutic retrospective case series.

A Manganese-based Alternative to Gadolinium: Contrast-enhanced MR Angiography, Excretion, Pharmacokinetics, and Metabolism

Purpose To compare intravascular contrast enhancement produced by the manganese-based magnetic resonance (MR) imaging contrast agent manganese-N-picolyl-N,N',N'-trans-1,2-cyclohexenediaminetriacetate (Mn-PyC3A) to gadopentetate dimeglumine (Gd-DTPA) and to evaluate the excretion, pharmacokinetics, and metabolism of Mn-PyC3A. Materials and Methods Contrast material-enhanced MR angiography was performed in baboons (Papio anubis; n = 4) by using Mn-PyC3A and Gd-DTPA. Dynamic imaging was performed for 60 minutes following Mn-PyC3A injection to monitor distribution and elimination. Serial blood sampling was performed to quantify manganese and gadolinium plasma clearance by using inductively coupled plasma mass spectrometry and to characterize Mn-PyC3A metabolism by using high-performance liquid chromatography. Intravascular contrast enhancement in the abdominal aorta and brachiocephalic artery was quantified by measuring contrast-to-noise ratios (CNRs) versus muscle at 9 seconds following Mn-PyC3A or Gd-DTPA injection. Plasma pharmacokinetics were modeled with a biexponential function, and data were compared with a paired t test. Results Aorta versus muscle CNR (mean ± standard deviation) with Mn-PyC3A and Gd-DTPA was 476 ± 77 and 538 ± 120, respectively (P = .11). Brachiocephalic artery versus muscle CNR was 524 ± 55 versus 518 ± 140, respectively (P = .95). Mn-PyC3A was eliminated via renal and hepatobiliary excretion with similar pharmacokinetics to Gd-DTPA (area under the curve between 0 and 30 minutes, 20.2 ± 3.1 and 17.0 ± 2.4, respectively; P = .23). High-performance liquid chromatography revealed no evidence of Mn-PyC3A biotransformation. Conclusion Mn-PyC3A enables contrast-enhanced MR angiography with comparable contrast enhancement to gadolinium-based agents and may overcome concerns regarding gadolinium-associated toxicity and retention. ^© RSNA, 2017 Online supplemental material is available for this article.

Correlation of Joint Volume and Passive Range of Motion With Capsulo-Synovial Thickness Measured by Contrast-Enhanced Magnetic Resonance Imaging in Adhesive Capsulitis

BACKGROUND

No study has investigated the relationship between the findings of contrast-enhanced magnetic resonance imaging (CE-MRI) and the joint volume of the shoulder, which has been considered the standard reference for diagnosis of adhesive capsulitis (AC).

OBJECTIVE

To investigate the relationships among the capsulo-synovial thickness measured by CE-MRI, joint volume, and passive range of motion (ROM) in patients with AC.

DESIGN

This was a retrospective study.

SETTING

The study took place at an institutional practice.

PATIENTS

Medical record of 103 patients (46 male and 57 female), who were treated with sonographically guided intra-articular injection with diagnosis of AC and underwent CE-MRI to rule out other concomitant shoulder disease, were retrospectively reviewed.

METHODS

Passive ROM and glenohumeral joint (GHJ) volume were measured before and during sonographically guided injection. The thickness of the enhancing portion of the capsulo-synovium was measured at the axillary recess and rotator interval on CE-MRI.

MAIN OUTCOME MEASUREMENTS

The relationship among the thickness of the enhancing portion on CE-MRI, GHJ volume, and passive ROM was analyzed using the Pearson correlation coefficient.

RESULTS

Capsulo-synovial thickness measured by CE-MRI at the enhancing portion of the axillary recess inversely correlated with GHJ volume (ρ = -0.444, P < .001), whereas at the rotator interval, this finding was not observed. At the axillary recess, the capsulo-synovial thickness inversely correlated with abduction (ρ = -0.400, P < .001), forward elevation (ρ = -0.378, P < .001), and external rotation (ρ = -0.297, P < .01), but at the rotator interval, such statistically significant correlations were not shown.

CONCLUSION

The capsulo-synovial thickness measured by CE-MRI at the enhancing portion of the axillary recess could represent obliterated joint capacity and clinical impairment (restricted passive ROM), which could help in diagnosing AC and in differentiating other shoulder diseases that may mimic this condition.

LEVEL OF EVIDENCE

III.

A prospective randomized study comparing three different approaches to fluoroscopy-guided shoulder arthrography according to the experience of practitioners

OBJECTIVE

To compare three approaches via the anterior and posterior glenohumeral joints, and the rotator interval in fluoroscopy-guided shoulder arthrography according to the experience of the practitioners.

MATERIALS AND METHODS

This prospective randomized study was originally designed to have 34 subjects for each approach, and finally evaluated 98 patients (mean age: 51.5 years; 55 men) from July to December 2014, who had shoulder arthrography via the anterior (n = 41) or posterior glenohumeral joint (n = 27) approaches, or via the rotator interval approach (n = 30) by residents (n=76) or fellows (n=22). The success rate, number of punctures, fluoroscopy time, radiation dose, and complications of the three methods were compared, and according to the practitioners.

RESULTS

The success rate was 100% for the anterior glenohumeral joint approach (34 out of 34), 90.0% for the posterior glenohumeral joint approach (23 out of 30), and 88.2% for the rotator interval approach (30 out of 34; p = 0.013). There was no difference in the success rate according to the practitioners' experience. Fluoroscopy time was longest for the posterior glenohumeral joint approach (mean: 95.44 s) and shortest for the rotator interval approach (mean: 31.57 s, p = 0.006). Radiation dose was larger by 1st- or 2nd-year residents (p = 0.014), with no difference among the three approaches. Only one patient who underwent arthrography using the posterior glenohumeral joint approach complained about post-procedural pain.

CONCLUSION

Fluoroscopy-guided shoulder arthrography via the posterior glenohumeral joint or rotator interval approach may be difficult for trainees, and the posterior glenohumeral joint approach may need a long fluoroscopy time.

Freehand direct arthrography of the shoulder using near real-time guidance in an open 1.0-T MRI scanner

OBJECTIVE

To assess the technical success and duration of magnetic resonance imaging (MRI)-guided freehand direct shoulder arthrography (FDSA) with near real-time imaging implemented in a routine shoulder MRI examination on an open 1.0-T MRI scanner, and to assess the learning curve of residents new to this technique.

METHODS

An experienced MRI interventionalist (the expert) performed 125 MRI-guided FDSA procedures, and 75 patients were treated by one of three residents without previous experience in MRI-guided FDSA. Technical success rate and duration of MRI-guided FDSA of the expert and the residents were compared. The residents' learning curves were assessed. The occurrence of extra-articular deposition and leakage of contrast media from the puncture site and the subsequent impairment of image interpretation were retrospectively analyzed.

RESULTS

Overall technical success was 97.5 %. The expert needed overall fewer puncture needle readjustments and was faster at puncture needle positioning (p < 0.01). The learning curve of the residents, however, was steep. They leveled with the performance of the expert after ≈ 15 interventions. With a minimal amount of training all steps of MRI-guided FDSA can be performed in ≤10 min.

CONCLUSION

Magnetic resonance-guided FDSA in an open 1.0-T MRI scanner can be performed with high technical success in a reasonably short amount of time. Only a short learning curve is necessary to achieve expert level.

Comparative analysis of anterior and posterior contrast injection approaches for shoulder MR arthrograms in adolescents

BACKGROUND

There is no consensus in the literature concerning the optimal approach for performing a fluoroscopically guided shoulder arthrogram injection in a pediatric population.

OBJECTIVE

To compare adequacy of capsular injection and radiation doses between fluoroscopically guided anterior and posterior glenohumeral joint contrast injections in adolescents.

MATERIALS AND METHODS

We evaluated imaging in 67 adolescents (39 boys, 28 girls; mean age 16.0 years; range 11.7-19.1 years) who underwent an anterior approach glenohumeral contrast injection with subsequent MR imaging, and 67 age- and gender-matched subjects (39 boys, 28 girls; mean age 16.0 years; range 11.1-19.2 years) who underwent a posterior approach injection during the period June 2010 to September 2015. Two pediatric radiologists independently evaluated all MR shoulder arthrograms to assess adequacy of capsular distention and degree of contrast extravasation. We recorded total fluoroscopic time, dose-area product (DAP) and cumulative air kerma (CAK).

RESULTS

There were no significant differences in age, gender, height, weight or body mass index between the populations (P-values > 0.6). The amount of contrast extravasation between the groups was not significantly different (P = 0.27). Three anterior injections (4.5%) and one posterior (1.5%) were suboptimal (P = 0.62). Fluoroscopy time was not different: 1.1 min anterior and 1.3 min posterior (P = 0.14). There was a significant difference in CAK (0.7 mGy anterior and 1.1 mGy posterior; P = 0.007) and DAP (5.3 μGym² anterior and 9.4 μGym² posterior; P = 0.008). Inter-rater agreement was excellent (Cohen kappa >0.81).

CONCLUSION

Both techniques were technically successful. There was no difference in the fluoroscopy time for either approach. The radiation dose was higher with the posterior approach but this is of questionable clinical significance.

Musculoskeletal interventional procedures: With or without imaging guidance?

Aspiration and injection of joints and soft tissues is an indispensable skill used in everyday practice by the clinical rheumatologist. Most rheumatologists recognise that performing these procedures using anatomical landmarks is not always successful, particularly in the case of small or infrequently injected joints, bursae or tendon sheaths. Musculoskeletal ultrasound confirms the local pathological-anatomical diagnosis and is the most applicable and feasible imaging method that can be applied in clinical practice in guiding musculoskeletal interventional procedures. From 1993, there has been substantial examination of the accuracy of landmark- and imaging-guided procedures. We have searched the literature and ascertained whether imaging techniques improve the accuracy of musculoskeletal procedures and whether the accuracy of needle placement can be translated into improved clinical outcome (efficacy).

Diagnostic Performance of MR Arthrography with Anterior Trans-Subscapularis versus Posterior Injection Approach for Subscapularis Tendon Tears at 3.0T

OBJECTIVES

To compare the diagnostic performance of shoulder magnetic resonance arthrography (MRA) with the anterior trans-subscapularis versus posterior injection approach to diagnose subscapularis tendon (SCT) tears.

METHODS

One hundred and sixty-seven arthroscopically confirmed patients (84 anterior and 83 posterior approaches) were included. Two readers retrospectively scored SCT tears. Proportions of correctly graded tears between MR arthrography and arthroscopy were calculated. Retrospective error analysis was performed.

RESULTS

The sensitivity and specificity were 80 % (24/30) and 72 % (39/54) by reader 1, 73 % (22/30) and 76 % (41/54) by reader 2 in the anterior approach, and 86 % (30/35) and 79 % (38/48) by reader 1, 80 % (28/35) and 88 % (42/48) by reader 2 in the posterior approach, respectively. There were no significant differences in sensitivity and specificity between the two groups. Proportions of correctly graded tears of both readers were 48 % and 36 % in the anterior approach, and 70 % and 68 % in the posterior approach, respectively. The intratendinous collection of contrast material was not statistically significantly different between anterior (n = 8) and posterior (n = 3) approach group.

CONCLUSIONS

For the MRA diagnosis of SCT tears, there was no significant difference between the anterior trans-subscapularis and the posterior approach.

KEY POINTS

• Anterior trans-subscapularis and posterior approaches showed no significant difference for SCT tears • Intratendinous collection of gadolinium is more frequent in anterior trans-subscapularis approach • Extent of SCT tears tends to be overestimated in anterior trans-subscapularis approach • Posterior approach should be considered for diagnosing SCT tear.

American Medical Society for Sports Medicine (AMSSM) position statement: interventional musculoskeletal ultrasound in sports medicine

The use of diagnostic and interventional ultrasound has significantly increased over the past decade. A majority of the increased utilization is by nonradiologists. In sports medicine, ultrasound is often used to guide interventions such as aspirations, diagnostic or therapeutic injections, tenotomies, releases, and hydrodissections. This American Medical Society for Sports Medicine (AMSSM) position statement critically reviews the literature and evaluates the accuracy, efficacy, and cost-effectiveness of ultrasound-guided injections in major, intermediate, and small joints, and soft tissues, all of which are commonly performed in sports medicine. New ultrasound-guided procedures and future trends are also briefly discussed. Based upon the evidence, the official AMSSM position relevant to each subject is made.

Accuracy of palpation-directed intra-articular glenohumeral injection confirmed by magnetic resonance arthrography

PURPOSE

The aim of this study was to determine the accuracy of anatomic palpation-directed injections in the office setting.

METHODS

Two hundred twenty-six shoulders in 208 patients were studied using a 0.2-Tesla extremity scanner after the injection of gadolinium-diethylene triamine pentaacetic acid-saline. All patients were injected in a sterile fashion by a single board-certified shoulder surgeon using an anterior approach by palpating the rotator interval anterior to the acromioclavicular joint and angling the needle 45° lateral and 45° caudad. All injections, successful or otherwise, were single injections. Magnetic resonance (MR) arthrograms were retrospectively read by 2 musculoskeletal fellowship-trained, board certified radiologists to determine whether the injection was in the glenohumeral joint.

RESULTS

Two hundred one of the 226 injections were successful (88.9%). Of the 25 unsuccessful injections, the contrast material extravasated out of the capsule in 5 cases and into the subscapularis tendon in 10 cases. The contrast material was injected into the subacromial space in 9 cases, into the rotator interval fat in 9 cases, and into extracapsular tissue in 6 cases. There was insufficient volume of contrast material in 10 cases. The accuracy rate was 88.9%. There were no complications.

CONCLUSIONS

The palpation-directed rotator interval anterior approach technique for intra-articular glenohumeral MR arthrogram injections performed by a single surgeon was 88.9% accurate.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Magnetic resonance arthrography of the glenohumeral joint: ultrasonography-guided technique using a posterior approach

OBJECTIVE

The purpose of this study was to assess the efficacy and feasibility of ultrasound (US)-guided magnetic resonance (MR) arthrography of the glenohumeral joint via a posterior approach.

MATERIALS AND METHODS

Thirty-four patients (18 males and 16 females) who were suspected to have glenohumeral joint pathology were examined using MR arthrography. The patients ranged in age from 21 to 85 years, and the average age was 45±15.9 years. A Toshiba Xario US unit was utilized. Ultrasonography examinations were conducted using a broad-band 5-12 MHz linear array transducer. Gadolinium was injected into the shoulder joint using an 18-20 gauge needle. MR imaging was performed within the first 30 min after the injection.

RESULTS

The injection of gadolinium into the shoulder joint was successfully accomplished in all 34 patients. Major contrast media extravasation outside the joint was depicted in only two patients (5.9%). No major complications were encountered.

CONCLUSION

Ultrasonography is an effective alternate guidance technique for the injection of gadolinium into the glenohumeral joint for MR arthrography. US-guided arthrography via a posterior approach to the glenohumeral joint is safe, accurate, well tolerated by patients and easy to perform with minimal training.

American Medical Society for Sports Medicine position statement: interventional musculoskeletal ultrasound in sports medicine

The use of diagnostic and interventional ultrasound has significantly increased over the past decade. A majority of the increased utilization is by nonradiologists. In sports medicine, ultrasound is often used to guide interventions such as aspirations, diagnostic or therapeutic injections, tenotomies, releases, and hydrodissections. This American Medical Society for Sports Medicine (AMSSM) position statement critically reviews the literature and evaluates the accuracy, efficacy, and cost-effectiveness of ultrasound-guided injections in major, intermediate, and small joints, and soft tissues, all of which are commonly performed in sports medicine. New ultrasound-guided procedures and future trends are also briefly discussed. Based on the evidence, the official AMSSM position relevant to each subject is made.

American Medical Society for Sports Medicine (AMSSM) position statement: interventional musculoskeletal ultrasound in sports medicine

BACKGROUND

The use of diagnostic and interventional ultrasound has significantly increased over the past decade. A majority of the increased utilisation is by non-radiologists. In sports medicine, ultrasound is often used to guide interventions such as aspirations, diagnostic or therapeutic injections, tenotomies, releases and hydrodissections.

OBJECTIVE

Critically review the literature related to the accuracy, efficacy and cost-effectiveness of ultrasound-guided injections (USGIs) in major, intermediate and small joints; and soft tissues.

DESIGN

Systematic review of the literature.

RESULTS

USGIs are more accurate than landmark-guided injections (LMGIs; strength of recommendation taxonomy (SORT) Evidence Rating=A). USGIs are more efficacious than LMGIs (SORT Evidence Rating=B). USGIs are more cost-effective than LMGIs (SORT Evidence Rating=B). Ultrasound guidance is required to perform many new procedures (SORT Evidence Rating=C).

CONCLUSIONS

The findings of this position statement indicate there is strong evidence that USGIs are more accurate than LMGI, moderate evidence that they are more efficacious and preliminary evidence that they are more cost-effective. Furthermore, ultrasound-guided (USG) is required to perform many new, advanced procedures and will likely enable the development of innovative USG surgical techniques in the future.

Comparing the accuracy of ultrasound versus fluoroscopy in glenohumeral injections: a systematic review and meta-analysis

OBJECTIVE

We performed a systematic review with meta-analysis to compare the accuracy of fluoroscopic-guided glenohumeral injections with that of ultrasound-guided glenohumeral injections as reported in prior studies.

METHODS

We reviewed the databases of MEDLINE, PubMed, and Google Scholar using combinations of the keywords "ultrasound," "fluoroscopy," "injection," and "shoulder" for articles reporting the injection accuracy, confirmed by imaging, of the first attempt under either fluoroscopic or ultrasound guidance. A meta-analysis was performed to assess the accuracy of fluoroscopic-guided glenohumeral injections versus ultrasound-guided glenohumeral injections.

RESULTS

Five of 42 pertinent studies met our inclusion criteria for a total of 406 glenohumeral injections, of which 115 were fluoroscopy-guided and 291 were ultrasound-guided. The meta-effect estimates for the proportion of joints successfully injected with ultrasound and fluoroscopic guidance were 93% (95% CI, 86% to 98%) and 80% (95% CI, 63% to 93%), respectively, which did not reach statistical significance (Q[df] = 2.55 [1], p = 0.11).

CONCLUSIONS

Our meta-analysis indicates that glenohumeral injections guided by ultrasound are more accurate than injections guided by fluoroscopy but this difference did not reach statistical significance. As the use of ultrasound does not expose the patient or practitioner to radiation, its similar accuracy may make it the preferred modality for image-guided glenohumeral joint injections. Limitations to our analysis include the retrospective nature, limited number of studies included, and the potential generalizability of our findings to regions outside of those included in our study.

Extra-articular contrast material leaks into locations unrelated to the injection path in shoulder MR arthrography

OBJECTIVES

To evaluate the localisation, frequency and amount of extravasation in patients with extra-articular contrast material leak into locations unrelated to the injection path in shoulder magnetic resonance (MR) arthrography and associated shoulder disorders.

METHODS

The sites of extravasation were determined on the shoulder MR arthrography of 40 patients. The extravasations were measured on three vertical planes of the MR arthrography. Sufficient joint distension was assessed according to the transverse diameters of the axillary recess on coronal MR images.

RESULTS

Extravasation of the contrast material occurred through the subscapular recess, the synovium of the biceps, and the axillary recess. In four cases, extravasations were observed in more than one anatomic location. The most common site of extravasation was along the subscapularis muscle. Superior labrum anterior-posterior (SLAP) lesions were found to be most frequently associated with extravasations. The amount of extravasation was significantly higher in patients with adhesive capsulitis compared with the patients with a different diagnosis (p = 0.022).

CONCLUSIONS

The extravasations adjacent to the axillary recess do not always indicate glenohumeral ligament pathology. Massive subscapular extravasations were most frequently associated with adhesive capsulitis and SLAP lesions, and might be considered in the MR arthrography report.

KEY POINTS

• Contrast material extravasation may reduce the diagnostic value of shoulder MR arthrography. • The extravasations may occur into locations unrelated to the injection path. • The extravasations adjacent to axillary recess can be misleading for HAGL lesion. • Massive subscapular extravasations were frequently associated with adhesive capsulitis and SLAP lesions.

A motive for the use of a posterior approach in shoulder arthography: ventral leakage of contrast medium

BACKGROUND

Some orthopedic surgeons request a posterior approach for shoulder magnetic resonance (MR) arthrography, especially in patients with anterior shoulder instability, to avoid interpretive difficulties in differentiating anterior extraarticular contrast injection when using an anterior approach from ventral leakage of contrast.

PURPOSE

To determine the occurrence of ventral leakage of contrast in shoulder MR arthrography when using a posterior approach.

MATERIAL AND METHODS

Retrospectively, we included 73 consecutive patients who underwent shoulder MR arthrography (1.0 Tesla) using the posterior approach. Three unsuccessful procedures were excluded. Ventral leakage of contrast, defined as contrast seen around the musculus subscapularis without distention of the posterior capsule, was recorded. Descriptive statistics were used.

RESULTS

Seventy shoulders were included. Forty-one left shoulders were involved (59%). Mean age of patients was 49 years (range, 17-76 years). Thirty-five patients were women (50%). Ventral leakage of contrast was seen in 12 shoulders (17%).

CONCLUSION

As ventral leakage of contrast was seen in a substantial number of cases when using a posterior approach in shoulder MR arthrography, the use of a posterior approach is advised to avoid misinterpretation of ventral contrast leakage with accidental extra articular contrast injection, and to increase confidence in the final radiological diagnosis.

An alternative injection technique for performing MR ankle arthrography: the lateral mortise approach

OBJECTIVES

This study evaluates whether the recently described lateral mortise (LM) approach to therapeutic ankle injections can also be used to inject the ankle prior to magnetic resonance arthrography (MRA) without impairing the evaluation of the anterior talofibular ligament (ATFL).

MATERIALS AND METHODS

An IRB-approved, retrospective review of ankle MRAs performed using the LM approach between April 2009 and April 2011 was conducted. The MRAs were independently evaluated by three musculoskeletal radiologists for: ATFL assessment (well assessed, limited or unable to assess), amount of fluid in the anterolateral soft tissues (none to large), and capsular distention (underdistended to overdistended). Patient age, gender, fluoroscopy time, injection location, degree of ankle arthritis, and ankle joint narrowing on radiographs were recorded. Statistical analysis was performed using exact binomial confidence limits.

RESULTS

Fifteen MRAs were successfully performed on 13 patients (mean age: 27 years, 11 male, 2 female). Mean fluoroscopic time was 39 s (range 9–108) and mean volume injected was 7 mL (range 5–9 mL). The ATFL was well assessed on all MRAs. A moderate to large amount of fluid was noted in the anterolateral soft tissues on 5 out of 15 MRAs. No ankle joints were underdistended, but 3 out of 15 were overdistended.

CONCLUSION

Since the ATFL is inferior to the location used for the LM injection, the interpretation of the ankle MRA, specifically ATFL evaluation, was not compromised in any patient. Therefore, the LM approach can be used as an alternative to the anteromedial approach for ankle MRA without sacrificing diagnostic quality.

Musculoskeletal aspiration procedures

With advances in imaging technology, there has been a significant increase in the number and range of interventional musculoskeletal image-guided procedures. One of the most commonly performed image-guided musculoskeletal interventions is the diagnostic and therapeutic percutaneous aspiration and drainage of multiple types of intra-articular, juxta-articular, and intramuscular pathologic fluid collections. These procedures may be performed under fluoroscopic, ultrasound, computed tomography, or even magnetic resonance guidance depending on the location to be accessed, type of pathology, patient characteristics, and operator preference. Musculoskeletal image-guided aspiration and drainage procedures are minimally invasive and generally very safe while offering valuable diagnostic information as well as therapeutic benefit. This article focuses on the appropriate indications, contraindications, and general technique for accessing the major joints via imaging guidance. For each joint, we discuss pertinent anatomy, appropriate imaging modalities, and preferred approaches to gaining intra-articular access. Additionally, the article discusses some of the more frequently encountered juxta-articular and intramuscular fluid collections that can be accessed and aspirated via percutaneous intervention, with mention of the importance of recognizing extremity sarcomas that can mimic these benign collections.

Ultrasound-guided shoulder MR arthrography: comparison of rotator interval and posterior approach

PURPOSE

The purpose of this study was to prospectively evaluate the two different ultrasound-guided injection techniques for magnetic resonance (MR) arthrography of the shoulder.

METHODS AND MATERIALS

This study included 100 patients [50 rotator interval group (n=50) vs. 50 posterior approach group (n=50)]. All procedures were performed by the same radiologist. The two injection techniques were compared. The discomfort during and after arthrography was evaluated. Extraarticular contrast media extravasation was graded according to the MRI findings. The number of injection attempts, effect of contrast media extravasation rate on diagnostic quality and procedure times were recorded.

RESULTS

There were no significant difference between the posterior and rotator interval puncture groups with regard to pain (P=.915), procedure times (P=.401) or attempt scores (P=.182). There were significantly more contrast media extravasations with rotator interval approach than posterior approach (P<.05).

CONCLUSION

Both techniques were successful and well tolerated by patients. Posterior injection technique provided a more effective route with decreased extravasation rate and easier approach compared to the rotator interval approach.

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.

Glenohumeral joint penetration with a 21-gauge standard needle

BACKGROUND

This study assessed whether a standard 21-gauge needle (length, 38.1 mm [1.5 inches]) is more likely to penetrate the glenohumeral joint through an anterior or a posterior approach.

METHODS

Seventy-nine patients underwent an arthroscopic procedure on the glenohumeral joint. The depth from the skin to the joint capsule was compared between the posterior approach (10 mm medial and inferior to the posterolateral tip of the acromion) and the anterior approach (direct visualization through the rotator interval). Each approach was measured twice and the mean used. The data were analyzed using a 2-sided paired t test.

RESULTS

The anterior approach was shorter than the posterior approach in all patients (P < .001). This was less than the length of a standard needle in 98.7% of patients. The mean skin-to-joint capsule depth was 43.5 mm (range, 24-58 mm) with the posterior approach and 27.1 mm (range, 12.5-40 mm) with the anterior approach. On average, the posterior approach was 16.3 mm deeper (range, 0.5-31.5 mm) than the anterior approach.

CONCLUSIONS

Injections through the anterior approach are more likely to penetrate the glenohumeral joint than through the posterior approach if a standard needle is used.

High origin of the anterior band of the inferior glenohumeral ligament: MR arthrography with anatomic and histologic correlation in cadavers

INTRODUCTION

The anterior band of the inferior glenohumeral ligament has been described to arise from the anteroinferior labrum, but we have observed that in some persons its origin is from the anterior or anterosuperior labrum, creating diagnostic difficulties.

MATERIALS AND METHODS

Ten fresh unembalmed cadaveric shoulders underwent magnetic resonance arthrography (MRA) using a posterior approach with a 1.5 T GE magnet, with the following sequences: T1-weighted fast spin-echo in axial, coronal and sagittal planes, and T1 fat-suppressed spin-echo in the axial plane (TR/TE 600/20, section thickness 2.5 mm, 0.5 mm interslice space, number of signals acquired, two, field of view 12 × 12 cm, and matrix 512 × 256 pixels). Following imaging, the shoulders were frozen and later sectioned using a band saw into 3-mm sections corresponding to the axial imaging plane. Histological analysis was also performed to determine the origin of the anterior band.

RESULTS

Four of the ten shoulders had an origin of the anterior band above or at the 3 o'clock position: one at the 1 o'clock position, two at the 2 o'clock position, and one at the 3 o'clock position. In another shoulder, the anterior band of the inferior glenohumeral ligament originated from the middle glenohumeral ligament, and in five other shoulders, the anterior band originated from the anteroinferior labrum as has been described in the literature.

CONCLUSIONS

This finding is of clinical significance as a high origin of the anterior band of the inferior glenohumeral ligament leads to MR arthrographic finding that can simulate those of labral tears or detachments.

Clinical utility of ultrasound guidance for intra-articular knee injections: a review

Intra-articular corticosteroid and hyaluronic acid injections provide short-term symptom amelioration for arthritic conditions involving structural damage or degenerative changes in the knee. Conventional palpation-guided anatomical injections frequently result in inaccurate needle placement into extra-articular tissue and adjacent structures. The purpose of this review was to determine the effect of ultrasound guidance on the accuracy of needle placement, clinical outcomes, and cost-effectiveness in comparison with anatomical landmark-guided intra-articular large joint injections, with particular emphasis on the knee. A total of 13 relevant studies were identified; five studied the knee, seven studied the shoulder, one used both the knee and shoulder, and none studied the hip. Ultrasound was used in seven studies; the remaining studies utilized air arthrography, fluoroscopy, magnetic resonance arthrography, or magnetic resonance imaging. Across all studies (using all imaging modalities and all joints), needle placement accuracy ranged from 63% to 100% with ultrasound and from 39% to 100% with conventional anatomical guidance. Imaging guidance improved the accuracy of intra-articular injections of the knee (96.7% versus 81.0%, P < 0.001) and shoulder (97.3% versus 65.4%, P < 0.001). In particular, ultrasound guidance of knee injections resulted in better accuracy than anatomical guidance (95.8% versus 77.8%, P < 0.001), yielding an odds ratio of 6.4 (95% confidence interval 2.9-14). Ultrasound guidance notably improves injection accuracy in the target intra-articular joint space of large joints including the knee. The enhanced injection accuracy achieved with ultrasound needle guidance directly improves patient-reported clinical outcomes and cost-effectiveness.

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.

Accuracy of glenohumeral joint injections: comparing approach and experience of provider

BACKGROUND

The purpose of this study was to prospectively evaluate the accuracy of three different approaches used for glenohumeral injections. In addition, the accuracy of the injection was compared to the experience and confidence of the provider.

METHODS

One-hundred six consecutive patients with shoulder pain underwent attempted intra-articular injection either posteriorly, supraclavicularly, or anteriorly. Each approach was performed by an experienced and inexperienced provider. A musculoskeletal radiologist blinded to technique used and provider interpreted fluoroscopic images to determine accuracy. Providers were blinded to these results.

RESULTS

The accuracy of the anterior approach regardless of experience was 64.7%, the posterior approach was 45.7%, and the supraclavicular approach was 45.5%. With each approach, experience did not provide an advantage. For the anterior approach, the experienced provider was 50% accurate compared to 85.7%. For the posterior approach, the experienced provider had a 42.1% accuracy rate compared to 50%. The experienced provider was accurate 50% of the time in the supraclavicular approach compared to 38.5%. The providers were not able to predict their accuracy regardless of experience. The experienced providers, when compared to those who were less experienced, were more likely to be overconfident, particularly with the anterior and supraclavicular approaches.

CONCLUSION

There was no statistically significant difference between the 3 approaches. The anterior approach was the most accurate, independent of the experience level of the provider. The posterior approach produced the lowest level of confidence regardless of experience. The experienced providers were not able to accurately predict the results of their injections, and were more likely to be overconfident with the anterior and supraclavicular approaches.