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.

Strategies for successful integration of work from home faculty in an academic radiology department.

Academic radiology departments have added increasing numbers of entirely remote "work-from-home" or hybrid faculty. This change has presented both an opportunity to recruit and retain faculty as well as a set of challenges to maintaining the full academic mission and educational environment. In this article we describe our experience with creating a remote faculty position and the key elements that we believe made it successful. Guiding principles for the department and faculty member accepting such a position are proposed and discussed.

Radiographic assessment of acute vs chronic vertebral compression fractures.

PURPOSE: Distinguishing between acute and chronic vertebral compression fractures typically requires advanced imaging techniques such as magnetic resonance imaging (MRI). Recognizing specific radiographic findings associated with fracture acuity may improve the accuracy of radiographic assessment. METHODS: Patients with compression fractures that had both radiographic and MRI studies of the lumbar spine within a 30-day time frame were retrospectively reviewed. MRI studies were used to determine compression fracture acuity. Radiographs were interpreted by a separate group of radiologists blinded to the MRI results. Radiographic findings of endplate osteophyte, subendplate density, subendplate cleft, and subendplate cyst were recorded as was the overall impression of fracture acuity. RESULTS: Sensitivity and specificity for radiographic reporting of acute fracture were 0.52 (95% CI: 0.42, 0.61) and 0.95 (95% CI: 0.93, 0.97) respectively. For chronic fractures, the sensitivity and specificity were 0.52 (95% CI: 0.41, 0.63) and 0.94 (95% CI: 0.92, 0.96). The radiographic presence of a subendplate cleft increased the odds of a fracture being acute by a factor of 1.75 (95% CI: 1.09, 2.81; P = 0.0202). The radiographic presence of subendplate density increased the odds of a fracture being acute by a factor of 1.78 (95% CI: 1.21, 2.63; P = 0.0037). The presence of an endplate osteophyte or subendplate cyst was not significantly associated with fracture acuity. CONCLUSION: Radiographs are relatively insensitive in distinguishing between acute and chronic lumbar compression fractures but the presence of a subendplate cleft or subendplate density increases the likelihood that a given fracture is acute.

MR Imaging of Knee Cartilage Injury and Repair Surgeries.

Cartilage injuries are common and may predispose to early accelerated osteoarthritis. Magnetic resonance (MR) imaging is critical in the detection and characterization of acute and chronic cartilage injuries. Several surgical approaches including microfracture, osteochondral allografting, autologous osteochondral transfer system, and autologous chondrocyte implantation have been developed to treat cartilage lesions. The goals of these treatments include relief of symptoms, restoration of joint function, and delay of progression of osteoarthritis. Imaging evaluation by MR imaging plays a crucial role in diagnosis and surgical planning as well as monitoring for postoperative complications.

Mass-Like Fat at the Medial Midfoot: A Common Pseudolesion.

Background Fatty masses are common and may be encountered in the foot and ankle. In some cases, normal subcutaneous fat may be mistaken for a discrete mass. Aims The aim of this study was to evaluate the common finding of prominent subcutaneous fat at the medial midfoot resembling a lipoma and to determine the prevalence of this pseudolesion by applying a series of potential size cutoff criteria. Materials and Methods Three musculoskeletal radiologists retrospectively evaluated 91 sequentially performed magnetic resonance imaging examinations of the ankle to measure fat resembling a discrete lipoma at the medial midfoot. Each blinded reader measured the largest area of continuous subcutaneous fat in orthogonal axial, coronal craniocaudal, and coronal transverse dimensions. Patient age, sex, and study indications were also recorded. Statistical analysis was performed with R and SAS 9.4 software Results A discrete fatty pseudolesion as defined by measuring at least 1 cm in all planes by measurements of at least two of three readers was present in 87% of cases (79 of 91). When a size criterion of 1.5 cm was used, a pseudolesion was documented in 14% of cases (13 of 91). There was a significant correlation between larger pseudolesion size and female sex in the axial plane; however, there was no correlation in the coronal craniocaudal and coronal transverse dimensions. Conclusions Subcutaneous fat at the medial midfoot often has a mass-like appearance that could be mistaken for a lipoma. It is important to recognize this pseudolesion variant and not to confuse the imaging appearance for a discrete mass.

MRI Evaluation of Repaired Versus Unrepaired Interportal Capsulotomy in Simultaneous Bilateral Hip Arthroscopy: A Double-Blind, Randomized Controlled Trial.

BACKGROUND: Techniques used in hip arthroscopy continue to evolve, and controversy surrounds the need for capsular repair following this surgical intervention. The purpose of this study was to evaluate the magnetic resonance imaging (MRI) appearance of the hip capsule in patients with femoroacetabular impingement (FAI) who underwent simultaneous bilateral hip arthroscopy through an interportal capsulotomy with each hip randomized to undergo capsular repair or not undergo such a repair. METHODS: This double-blind, randomized controlled trial included 15 patients (30 hips), with a mean age of 29.2 years, who underwent simultaneous bilateral hip arthroscopy utilizing a small (<3-cm) interportal capsulotomy for the treatment of FAI. The first hip treated in each patient was intraoperatively randomized to undergo capsular repair or no capsular repair. The contralateral hip then received the opposite treatment. MRI was performed at 6 and 24 weeks postoperatively, and the scans were analyzed by 2 musculoskeletal radiologists. The patients and the radiologists were blinded to the treatment performed on each hip. Capsular dimensions were measured at the level of the healing capsulotomy site and, for hips with a persistent defect, at locations both proximal and distal to the defect. These values were then analyzed at both time points to assess the rate and extent of capsular healing. RESULTS: At 6 weeks postoperatively, a continuous hip capsule (with no apparent capsulotomy defect) was observed in 8 hips treated with capsular repair and 3 hips without such a repair. Of the 19 hips with a discontinuous capsule at 6 weeks, 17 were available for follow-up at 24 weeks postoperatively; all 17 demonstrated progression to healing, with a contiguous appearance without defects and no difference in capsular dimensions between treatment cohorts. CONCLUSIONS: Arthroscopic repair of a small interportal hip capsulotomy site yields an insignificant increase in the percentage of continuous hip capsules seen on MRI at 6 weeks postoperatively compared with no repair. Repaired and unrepaired capsulotomy sites progressed to healing with a contiguous appearance on MRI by 24 weeks postoperatively. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

A multicenter, double-blind, randomized controlled trial comparing magnetic resonance imaging evaluation of repaired versus unrepaired interportal capsulotomy in patients undergoing hip arthroscopy for femoroacetabular impingement.

The purpose of this study was to evaluate the magnetic resonance imaging (MRI) appearance of the hip capsule in patients with femoroacetabular impingement (FAI) undergoing hip arthroscopy with capsular repair versus non-repair. A multicenter clinical trial was performed with 31 patients (49 hips) undergoing hip arthroscopy for treatment of FAI. A small- to moderate-sized interportal capsulotomy was performed. Each hip was randomized to capsular repair versus non-repair of the interportal capsulotomy. MRI was performed at 6 and 24 weeks postoperatively and was analyzed by two musculoskeletal radiologists. Patients and the radiologists were blinded to the treatment applied. Capsular defect size and capsule thickness were recorded on each scan. Mean patient age was 31.4 years. Capsular repair was performed in 23 (46.9%) hips. Mean capsulotomy length was 35 mm at Center X and 23 mm at Center Y. At 6 weeks postoperatively, a healed hip capsule (with no apparent capsulotomy defect) was observed in 10 (43.4%) hips that underwent capsular repair and 4 (15.4%) hips that did not undergo capsular repair (P = 0.13). At 24 weeks postoperatively, 25/30 hips (83.3%) achieved complete closure of the capsulotomy defect, with no significant difference between treatment groups. Repair of an interportal capsulotomy following hip arthroscopy for FAI results in a non-significantly higher percentage of healed hip capsules at 6 weeks postoperatively compared with leaving the capsule unrepaired, though the difference normalizes by 24-week follow-up. Repair of a small- to moderate-sized interportal capsulotomy does not provide a radiographic advantage following hip arthroscopy for FAI.

Postoperative Imaging in the Setting of Hip Preservation Surgery.

Osteoarthritis of the hip remains a prevalent disease condition that influences ever-changing treatment options. Procedures performed to correct anatomic variations, and, in turn, prevent or slow the progression of osteoarthritis, are aptly referred to as types of hip preservation surgery (HPS). Conditions that predispose individuals to femoroacetabular impingement (FAI), including pincer- and cam-type morphology, and hip dysplasia are specifically targeted in HPS. Common surgical interventions include acetabuloplasty, osteochondroplasty, periacetabular osteotomy (PAO), and derotational femoral osteotomy (DFO). The radiologist's understanding of the surgical approach, pre- and postoperative imaging findings, and common complications of HPS are paramount to providing value to the patient and surgeon. Acetabuloplasty and osteochondroplasty are performed to address pincer- and cam-type morphology in patients with FAI. With both of these HPS techniques, the goal is to restore the normal morphology by resecting excess bone in the acetabulum or femoral head or neck. As a result, a frequently encountered complication is incomplete or excessive resection. Excessive resection can predispose the patient to dislocation in the case of acetabuloplasty and fracture in the case of osteochondroplasty. Iatrogenic injury to adjacent structures such as the ischiofemoral ligament and acetabular cartilage also may occur. Although rare, especially when an arthroscopic approach is used, avascular necrosis remains a risk. Femoral head undercoverage in hip dysplasia is corrected by using PAO, which may be performed as the sole procedure or in conjunction with DFO. Incomplete or excessive rotation during surgery can result in postprocedural complications. As with any orthopedic procedure involving osteotomy, nonhealing is a risk. Iatrogenic injury in the form of fracture or hardware failure also may be seen. ©RSNA, 2016.

Introduction of a virtual workstation into radiology medical student education.

OBJECTIVE. This article describes the creation of a virtual workstation for use by medical students and implementation of that workstation in the reading room. CONCLUSION. A radiology virtual workstation for medical students was created using OsiriX imaging software to authentically simulate the experience of interacting with cases selected to cover important musculoskeletal imaging diagnoses. A workstation that allows the manipulation and interpretation of complete anonymized DICOM images may enhance the educational experience of medical students.

Video: Ultrasound-guided intervention at the posterior hip.

OBJECTIVE: The purpose of this video article is to demonstrate sonographic anatomy at the posterior hip and to describe a number of diagnostic and therapeutic interventions that may be performed at this location with sonographic guidance. Injection techniques at the piriformis muscle, ischial bursa, hamstring origin, and ischiofemoral space are described and demonstrated. CONCLUSION: Ultrasound is well adapted to the evaluation and treatment of conditions encountered at the posterior hip. Sonographic guidance is a useful tool that allows a trained operator to safely and effectively perform a range of injections.

Prevalence of abnormal hip findings in asymptomatic participants: a prospective, blinded study.

BACKGROUND: The prevalence of abnormal magnetic resonance imaging (MRI) findings in an asymptomatic population has yet to be determined. PURPOSE: The purpose of this study was to assess a cohort of asymptomatic people to determine the prevalence of hip lesions. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Forty-five volunteers with no history of hip pain, symptoms, injury, or surgery were recruited for enrollment in this institutional review board-approved study. The subjects underwent a unilateral MRI scan with a Siemens 3.0-tesla scanner. The extremity side evaluated by MRI was alternated. All MRI scans were reviewed by 3 fellowship-trained musculoskeletal radiologists. The scans were mixed randomly with 19 scans from symptomatic patients to blind the radiologists to the possibility of patient symptoms. An abnormal finding was considered positive when 2 of 3 radiologists agreed on its presence. RESULTS: The average age of volunteers was 37.8 years (range, 15-66 y); 60% were men. Labral tears were identified in 69% of hips, chondral defects in 24%, ligamentum teres tears in 2.2%, labral/paralabral cysts in 13%, acetabular bone edema in 11%, fibrocystic changes of the head/neck junction in 22%, rim fractures in 11%, subchondral cysts in 16%, and osseous bumps in 20%. Participants older than 35 years were 13.7 times (95% CI, 2.4-80 times) more likely to have a chondral defect and 16.7 times (95% CI, 1.8-158 times) more likely to have a subchondral cyst compared with participants 35 or younger. No other joint lesions were associated with age. Male subjects were 8.5 times (95% CI, 1.2-56 times) more likely to have an osseous bump than female subjects. No other joint lesions were associated with sex. CONCLUSION: Magnetic resonance images of asymptomatic participants revealed abnormalities in 73% of hips, with labral tears being identified in 69% of the joints. A strong correlation was seen between participant age and early markers of cartilage degeneration such as cartilage defects and subchondral cysts.

Brief report: airways abnormalities and rheumatoid arthritis-related autoantibodies in subjects without arthritis: early injury or initiating site of autoimmunity?

OBJECTIVE: To evaluate the presence of pulmonary abnormalities in rheumatoid arthritis (RA)-related autoantibody-positive subjects without inflammatory arthritis. METHODS: Forty-two subjects who did not have inflammatory arthritis but were positive for anti-cyclic citrullinated peptide antibodies and/or ≥2 rheumatoid factor isotypes (a profile that is 96% specific for RA), 15 autoantibody-negative controls, and 12 patients with established seropositive early RA (<1-year duration) underwent spirometry and high-resolution computed tomography (HRCT) lung imaging. RESULTS: The median age of autoantibody-positive subjects was 54 years, 52% were female, and 38% were ever-smokers; these characteristics were not significantly different from those of autoantibody-negative control subjects. No autoantibody-positive subject had inflammatory arthritis based on joint examination. HRCT revealed that 76% of autoantibody-positive subjects had airways abnormalities including bronchial wall thickening, bronchiectasis, centrilobular opacities, and air trapping, compared with 33% of autoantibody-negative controls (P = 0.005). The prevalence and type of lung abnormalities among autoantibody-positive subjects were similar to those among patients with early RA. In 2 autoantibody-positive subjects with airways disease, inflammatory arthritis classifiable as articular RA developed ∼13 months after the lung evaluation. CONCLUSION: Airways abnormalities that are consistent with inflammation are common in autoantibody-positive subjects without inflammatory arthritis and are similar to airways abnormalities seen in patients with early RA. These findings suggest that the lung may be an early site of autoimmune-related injury and potentially a site of generation of RA-related autoimmunity. Further studies are needed to define the mechanistic role of lung inflammation in the development of RA.

Morphologic imaging of articular cartilage.

Magnetic resonance (MR) imaging plays an integral role in the assessment of articular cartilage. This article discusses the role of MR imaging in the evaluation of articular cartilage, the appearance of cartilage lesions on MR imaging, and the currently available MR imaging techniques for evaluating cartilage morphology. A limitation of currently available sequences is their inability to consistently detect superficial degenerative and posttraumatic cartilage lesions that may progress to more advanced osteoarthritis. In the future, improved image quality may allow for better evaluation of articular cartilage and earlier detection of cartilage lesions.