Catherine L. Hayter

MRI after arthroplasty: comparison of MAVRIC and conventional fast spin-echo techniques.

OBJECTIVE The goal of this study was to evaluate the quality of images obtained with a prototype imaging technique, multiacquisition variable-resonance image combination (MAVRIC), compared with fast spin-echo (FSE) images in the evaluation of patients who have undergone hip, shoulder, or knee arthroplasty. MATERIALS AND METHODS MRI with metal-artifact reduction FSE and MAVRIC sequences was performed in the care of 122 patients who had undergone 74 hip, 27 shoulder, and 21 knee arthroplasties. The FSE and MAVRIC images were subjectively graded for visualization of the synovium, prosthesis-bone interface, and hip abductors or supraspinatus tendon. The presence of synovitis, osteolysis, or supraspinatus tendon tear was recorded. RESULTS Visualization of the synovium was significantly better on MAVRIC images than on FSE images of the hip (p < 0.0001), shoulder (p < 0.01), and knee (p < 0.01). Synovitis was detected only on the MAVRIC images of nine subjects (12%) who had undergone hip arthroplasty and five subjects (18%) who had undergone shoulder arthroplasty. Visualization of the periprosthetic bone was significantly better on MAVRIC images of the hip (p < 0.0001), shoulder (p < 0.0001), and knee (p < 0.01). Osteolysis was detected only on the MAVRIC images of 12 subjects (16%) who had undergone hip arthroplasty, six (22%) who had undergone shoulder arthroplasty, and five (24%) who had undergone knee arthroplasty. Visualization of the supraspinatus tendon was significantly better on MAVRIC images (p < 0.0001). Supraspinatus tendon tears in 12 subjects (44%) were detected only on MAVRIC images. CONCLUSION MAVRIC complements the information on FSE images after arthroplasty and is a useful additional sequence, particularly when there is concern about synovitis, periprosthetic osteolysis, or the presence of a supraspinatus tendon tear.

Clinical and MRI outcomes after platelet-rich plasma treatment for knee osteoarthritis.

The purpose of this study was to investigate whether platelet-rich plasma therapy for early knee osteoarthritis is associated with good clinical outcomes and a change in magnetic resonance imaging (MRI) structural appearances. The design was a prospective cohort study following patients 1 year after platelet-rich plasma therapy for knee osteoarthritis. Twenty-two patients were treated with platelet-rich plasma for early osteoarthritis, confirmed with a baseline MRI. Inclusion criteria were Kellgren grade 0-II with knee pain in patients aged 30 to 70 years. All the patients received a 6-mL platelet-rich plasma injection using the Cascade system. Fifteen subjects underwent clinical assessments at baseline, 1 week, and 1, 3, 6, and 12 months, and MRIs at 1 year. Pain scores significantly decreased, whereas functional and clinical scores increased at 6 months and 1 year from baseline. Qualitative MRIs demonstrated no change per compartment in at least 73% of cases at 1 year.

Magnetic resonance imaging of the postoperative hip

Magnetic resonance imaging (MRI) is ideally suited to imaging the patient with painful hip arthroplasty due to its superior soft tissue contrast, multiplanar capabilities, and lack of ionizing radiation. MRI is the most accurate imaging modality in the assessment of periprosthetic osteolysis and wear‐induced synovitis, and can also assess regional tendons and neurovascular structures. This article discusses the technical aspects of MRI around metallic implants as well as the appearance of potential complications following hip arthroplasty, including osteolysis, wear‐induced synovitis, infection, hemarthrosis, fracture, loosening, component displacement, heterotopic ossification, tendinopathy, and neurovascular impingement. The specific complication of metal hypersensitivity following metal‐on‐metal prostheses is reviewed. J. Magn. Reson. Imaging 2012;35:1013‐1025.

MRI Findings in Painful Metal-on- Metal Hip Arthroplasty

OBJECTIVE The objective of our study was to compare the frequency of osseous and soft-tissue abnormalities in patients presenting with hip pain after resurfacing arthroplasty and after total hip arthroplasty (THA), correlate the MRI findings with histologic results, and determine which MRI findings are predictive of aseptic lymphocytic vasculitis-associated lesions. MATERIALS AND METHODS The MRI examinations of patients with metal-on-metal hip prostheses placed at resurfacing arthroplasty (n=31) or THA (n=29) were reviewed for osteolysis, synovitis, extracapsular disease, synovial pattern, and mode of decompression into adjacent bursae. Regional muscles and tendons were assessed for tendinosis, tear, atrophy, and edema. Histologic and operative findings were reviewed in 19 patients (20 hips) who underwent revision surgery. Chi-square tests were performed to detect differences between the resurfacing arthroplasty and THA groups. The Wilcoxon rank sum test was performed to detect differences in MRI findings in patients with and those without aseptic lymphocytic vasculitis-associated lesions. RESULTS Synovitis was detected in 77.4% of resurfacing arthroplasty hips and 86.2% of THA hips. Extracapsular disease was present in 6.5% of resurfacing arthroplasty hips and 10.3% of THA hips. Osteolysis was detected in 9.7% of resurfacing arthroplasty hips and 24.1% of THA hips. There was no difference in the incidence of synovitis (p=0.51), osteolysis (p=0.17), or extracapsular disease (p=0.67) between the resurfacing arthroplasty and THA groups. Patients with aseptic lymphocytic vasculitis-associated lesions had higher volumes of synovitis (p=0.04) than patients without aseptic lymphocytic vasculitis-associated lesions. Extracapsular disease and muscle edema were seen only in patients with aseptic lymphocytic vasculitis-associated lesions. CONCLUSION Synovitis is common in patients with metal-on-metal hip prostheses and occurs with a similar incidence after resurfacing arthroplasty and after THA; osteolysis and extracapsular disease are uncommon. The MRI signs most suggestive of aseptic lymphocytic vasculitis-associated lesions are high volumes of synovitis, extracapsular disease, and intramuscular edema.

Imaging of Metal-On-Metal Hip Resurfacing

Conventional radiography is the primary imaging modality to evaluate the condition of hip resurfacing implants and the preferred method of assessing implant stability over time. Radiographs assess the angle of inclination of the femoral and acetabular components, implant stability, and femoral neck narrowing. Ultrasonography detects solid or soft tissue masses adjacent to the implant. Magnetic resonance imaging (MRI) detects osteolysis and complications in the periprosthetic soft tissues such as wear-induced synovitis, periprosthetic collections, neurovascular compression, and quality of the muscle and tendons of the rotator cuff of the hip. For pain after hip resurfacing, early use of optimized MRI is recommended.

Lamellated Hyperintense Synovitis: Potential MR Imaging Sign of an Infected Knee Arthroplasty

PURPOSE To determine the sensitivity and specificity of lamellated hyperintense synovitis for infection following knee arthroplasty and to determine the inter- and intraobserver variability of this sign at magnetic resonance (MR) imaging. MATERIALS AND METHODS The purpose of the retrospective case control study was approved by the hospitals institutional review board. MR images from 28 patients with proved infected total knee arthroplasty and 28 patients with noninfected arthroplasty were reviewed by two musculoskeletal radiologists for the presence of lamellated hyperintense synovitis. Cases were rereviewed 2 weeks later by each reader. The sensitivity and specificity were calculated with the initial reads. The κ statistic was used to assess inter- and intraobserver reliability. RESULTS The sensitivity of lamellated hyperintense synovitis for infection was 0.86-0.92 (95% confidence interval [CI]: 0.75, 0.97) and the specificity was 0.85-0.87 (95% CI: 0.74, 0.94). There was almost perfect interobserver agreement (κ = 0.82; 95% CI: 0.72, 0.93; P < .001) and intraobserver agreement (for reader 1, κ = 0.89 [95% CI: 0.78, 1.00; P < .001] and for reader 2, κ = 0.89 [95% CI: 0.77, 1.00; P < .001]) in the classification of the synovial pattern. CONCLUSION In this selected series of patients, the presence of lamellated hyperintense synovitis at MR imaging of knee arthroplasty had a high sensitivity and specificity for infection. This sign had high inter- and intraobserver reliability.

Magnetic resonance imaging of the wrist: Bone and cartilage injury

Magnetic resonance imaging (MRI) is particularly useful for imaging the wrist due to its superior soft tissue contrast and ability to detect subtle bone marrow changes and occult fractures. A high field (1.5T or greater) strength, dedicated wrist coil, and high in‐plane and through‐plane resolution must be utilized to successfully visualize the relatively thin cartilage of the wrist. MRI can be used to detect occult carpal bone fractures, identify complications following scaphoid fractures, and assess for avascular necrosis in the setting in Kienböcks and Preisers disease. MRI is useful to identify secondary soft tissue and chondral pathology in impaction/impingement syndromes. The use of an intermediate‐echo time fast spin echo sequence allows for accurate assessment of articular cartilage, allowing evaluation of chondral wear in the setting of primary osteoarthritis and posttraumatic degenerative arthrosis. MRI is the most sensitive imaging modality for the detection of early inflammatory arthropathies and can detect synovitis, bone marrow edema, and early erosions in the setting of negative radiographs. J. Magn. Reson. Imaging 2013;37:1005–1019.

Posterior Interosseous Neuropathy: Electrodiagnostic Evaluation

Electrodiagnostic studies are used to anatomically localize nerve injuries. These tests help differentiate between cervical radiculopathies, brachial plexopathies, and peripheral nerve injuries. They also help to identify or rule out other underlying neurological diseases and disorders. In this case report, a 22-year-old male swimmer presented with left finger extensor weakness following pull-up exercises. Left wrist extension remained intact. Electrodiagnostic testing revealed a severe but incomplete posterior interosseous neuropathy. Magnetic resonance imaging confirmed inflammation of the nerve in the forearm. Posterior interosseous neuropathy is an uncommon but well-studied condition. Typically, this condition presents with weakness in finger and thumb extension with preserved wrist extension as the extensor carpi radialis longus is innervated proximal to the site of nerve compression in most cases. It is important to understand the anatomic course and distribution of the radial nerve in order to make an accurate diagnosis. Once the anatomy is understood, electrodiagnostic testing may be used to identify the location of nerve injury and exclude other disorders.

Comparative Analysis of 2- Versus 3-Dimensional Sonography of the Supraspinatus Tendon

The purpose of this study was to determine the reliability in the analysis of images acquired using a dedicated 3‐dimensional (3D) ultrasound transducer and conventional 2‐dimensional (2D) images in the detection and characterization of supraspinatus tendon tears.

Clinical and Magnetic Resonance Imaging Outcomes Following Platelet Rich Plasma Treatment for Elbow Tendinosis

Back Ground: Platelet Rich Plasma is now being utilized for patients with tendinosis and arthritis. This treatment option in many instances has replaced the need for surgery. Hypothesis: The purpose of this study was to investigate if Platelet Rich Plasma (PRP) treatment of elbow tendinosis is associated with improved clinical outcomes with respect to pain, function and return to sports/ recreation. Also to determine if an MRI would detect any significant structural changes of the tendon after treatment. Study Design: Prospective case series, Level of Evidence: IV Methods: This study evaluated 114 patients treated with PRP for either lateral or medial elbow tendinosis. Tendinopathy was confirmed with a baseline MRI in all patients. Subjects completed serial visual analog scales (VAS) to assess pain, elbow function and sports/recreational activity levels at 6 and 12 months post-injection. An additional retrospective score was recorded approximately 24 months post-injection. 17 patients had post-treatment MRIs between 6 months and 1 year to assess healing. Results: The average age of patients was 51.9 years with 43% (49) females and 57% (65) males. Extensor Tendinosis was diagnosed in 65% (74) and flexor tendinosis in 35% (40) patients. VAS pain scores at 6 months were reduced significantly (61%) and at 1 year (69%) from baseline, with a 2 year (83%) reduction (p<0.001). Functional scores at 6 months increased significantly (64%) at 6 months and at 1 year (76%) from baseline with maintenance at 2 years of a (77%) improvement (p<0.001)). Sports/recreational level scores at 6 months increased significantly (81%) and at 1 year (165%) from baseline, with a 2 year (107%) improvement (p<0.001). No differences in outcomes were noted between medial versus lateral tendinosis. MRI in a limited number of patients compared to baseline demonstrated an improvement in the appearance of tendinosis (47.19%) and partial tears (44%). Conclusion: PRP treatment for lateral or medial elbow tendinosis resulted in significant improvements in pain levels, elbow function and sports/recreational activities. This study suggests that PRP may improve clinical outcomes for up to two years. Clinical Relevance: Yes