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.

Imaging of the Diabetic Foot.

Diabetic foot complications are increasingly prevalent in the world, leading to significant morbidity and driving up associated health care costs. Complex pathophysiology and suboptimal specificity of current imaging modalities have made diagnosis challenging, mainly in the evaluation of superimposed foot infection to underlying arthropathy or other marrow lesions. Recent advances in radiology and nuclear medicine have the potential to streamline the assessment of diabetic foot complications. But we must be aware of the specific strengths and weaknesses of each modality, and their applications. This review offers a comprehensive approach to the spectrum of diabetic foot complications and their imaging appearances in conventional and advanced imaging studies, including optimal technical considerations for each technique. Advanced magnetic resonance imaging (MRI) techniques are highlighted, illustrating their complementary role to conventional MRI, in particular their potential impact in avoiding additional studies.

Imaging of Acute Ankle and Foot Sprains.

Ankle and foot injuries are very common injuries in the general population, and more so in athletes. MR imaging is the optimal modality to evaluate for ligamentous injuries of the ankle and associated conditions after ankle sprain. In this article, the authors discuss the epidemiology, biomechanics, normal anatomy, and pathology of the ankle as well as injuries of the hindfoot and midfoot that are often associated with ankle injuries.

Past, present, and future in sports imaging: how to drive in a three-lane freeway.

KEY POINTS: • Morphological evaluation of SRIs is still nowadays the clinical standard in daily practice.• New functional imaging modalities show potential to add valuable physiopathological information about the insights of SRIs in specific clinical scenarios.• In the era of personalized medicine, AI algorithms may help athletes and all professionals involved in their care to improve the evaluation of SRIs through a definitive quantitative metric approach.

Postoperative Magnetic Resonance Imaging of the Knee Ligaments.

In this article, we describe the postoperative appearances of the reconstructed ligaments of the knee focusing on the anterior cruciate ligament (ACL). The expected evolving signal alterations of the graft over time are also reviewed. The postoperative appearance of the ligamentous reconstruction in patients with multiligamentous knee injuries (MLKI) and isolated PCL tears are also discussed.

Imaging of Nerve Disorders in the Elbow.

Neuropathies of the elbow represent a spectrum of disorders that involve more frequently the ulnar, radial, and median nerves. Reported multiple pathogenic factors include mechanical compression, trauma, inflammatory conditions, infections, as well as tumor-like and neoplastic processes. A thorough understanding of the anatomy of these peripheral nerves is crucial because clinical symptoms and imaging findings depend on which components of the affected nerve are involved. Correlating clinical history with the imaging manifestations of these disorders requires familiarity across all diagnostic modalities. This understanding allows for a targeted imaging work-up that can lead to a prompt and accurate diagnosis.

Nerve Entrapments in the Pelvis and Hip.

Clinical symptoms of pelvic entrapment neuropathies are widely variable and frequently nonspecific, thus rendering it difficult to localize and diagnose. Magnetic resonance imaging (MRI), and in particular MR neurography, has become increasingly important in the work-up of entrapment neuropathies involving the pelvic and hip nerves of the lumbosacral plexus. The major sensory and motor peripheral nerves of the pelvis and hip include the sciatic nerve, superior and inferior gluteal nerves, femoral nerve, lateral femoral cutaneous nerve, obturator nerve, and pudendal nerve. Familiarity with the anatomy and imaging appearance of normal and pathologic nerves in combination with clinical presentation is crucial in the diagnosis of entrapment neuropathies.

Humeral lesser tuberosity avulsion fractures - magnetic resonance imaging characteristics in the pediatric population.

BACKGROUND: Avulsion fractures of the humeral lesser tuberosity are rare injuries in skeletally immature patients and can pose a diagnostic challenge that often leads to delayed identification. OBJECTIVE: To describe the demographics, mechanism of injury and magnetic resonance imaging (MRI) findings of lesser tuberosity avulsion fractures in children. MATERIALS AND METHODS: A retrospective search of children with lesser tuberosity avulsion fractures on MRI was done. Available radiographs were evaluated. Demographics, mechanism of injury, MRI characteristics and treatment were recorded. RESULTS: Thirteen children, all male, were included (median age: 13.8 years, range: 12.5-16.8 years). The most common mechanism was blunt, overhead or hyperextension traumatic injury related to sports. All patients were skeletally immature and 10/13 demonstrated isolated avulsion fractures at the footprint. Only one patient had associated osteochondral injury to the humeral head and labral tear. Two children demonstrated medial dislocation/subluxation of the biceps tendon. The median size of the avulsed fragment was 15 mm (range: 5-29 mm), median anteroposterior displacement was 3 mm (range: 0-6 mm) and medial displacement was 1 mm (range: 0-20 mm). There was no correlation between age and the size of the avulsed fragment (P=0.29). Common injury patterns were complete avulsion of the subscapularis footprint (6/13) and partial avulsion of inferior footprint (6/13). Two-thirds of the radiographs were initially reported as normal, but retrospectively showed two missed fractures. One of the initial radiographs raised concern for bone tumor. The best view for identifying an avulsion fragment was the axillary view. Seven patients of the 13 patients underwent internal fixation. CONCLUSION: Avulsion fractures of the lesser tuberosity are rare, challenging to diagnose and often radiographically occult. MRI can identify the injury at the subscapularis tendon footprint with variable size and displacement. The long head of the biceps tendon is usually normal in location. Although this entity is rare, radiologists should be aware of it to allow for correct and prompt diagnosis and prevent unnecessary biopsy or contrast administration.

The smoke sign: a secondary sign of unsuspected acute pectoralis major tendon injury on routine shoulder MRI.

OBJECTIVE: To study the diagnostic utility of the "smoke sign" to detect unsuspected acute pectoralis major tendon injury on routine shoulder MRI. MATERIALS AND METHODS: Retrospective study of 52 shoulder MRI in patients with (38) and without (14) acute pectoralis major injury confirmed on imaging. Two readers independently reviewed shoulder MRI for the presence of the "smoke sign"-feathery soft tissue edema lateral or anterior to short head biceps/coracobrachialis on fluid-sensitive coronal-oblique and sagittal-oblique images, respectively. RESULTS: The smoke sign was present on shoulder MRI in 24/24 (100%) humeral avulsions, 4/4 (100%) tendon tears, 4/8 (50%) of myotendinous junction injuries, and 0/2 (0%) intramuscular injuries. The smoke sign was present in 0/14 examinations without acute pectoralis major injury. CONCLUSION: While dedicated pectoralis MRI remains the preferred method for imaging pectoralis injury, the "smoke sign" can serve as an easy to recognize finding on routine shoulder MRI that can raise the suspicion of an acute pectoralis major tendon injury. Its detection should prompt evaluation of the pectoralis major tendon and recommendation for dedicated imaging to confirm and evaluate the full extent of injury.

Gender Disparity in Radiology Society Committees and Leadership in North America and Comparison With Other Continents.

PURPOSE: To evaluate gender distribution in radiology professional society leadership positions. Our study intends to assess and compare the gender distribution among leadership roles and professional society committee memberships of the radiology societies and seek an understanding of potential associations between gender, academic research metrics, institutional academic rank, and leadership roles. METHODS: We identified radiology professional society committee members to assess relative gender composition in 28 radiology societies in North America, Europe, and Australia/New Zealand. The research metrics were obtained from the SCOPUS database and demographics and institutional affiliation through institutional websites' internet searches. Gender distribution by academic ranks and other discontinuous variables were analyzed using the Chi-Square test. Wallis tests. RESULTS: Of the 3011 members of society committees, 67.9% were male, and 32.1% female. Among all the society members, the data showed that the proportion of committee members holding leadership positions was comparable between males (25.7%) and females (22.5%). However, when we did a subgroup analysis and disaggregated the data by leadership positions, we noted that among those who held the leadership positions, the proportion of males was more significant (n = 526, 70.7%) compared to females (n = 218, 29.3%). Overall, males had higher median publications, citations, H-indices, and active years of research (P< 0.0001). At all university academic ranks, men outnumbered females (P = 0.0015, Chi-square 15.38), with the most considerable disparity at the rank of professor (71.9% male, 28.1% female, P = 0.0003). CONCLUSION: There was male predominance amongst committee members in radiology societies. Our study found no significant differences between those in leadership positions, suggesting that once a member of a committee, females are equally likely as males to attain leadership positions. Analysis of committee members' academic rank and committee leaders demonstrated underrepresentation of females at higher academic ranks, and males overall had higher research metrics than females.

ACR Appropriateness Criteria® Chronic Foot Pain.

Chronic foot pain is a frequent clinical complaint, which can significantly impact the quality of live in some individuals. These guidelines define best practices with regards to requisition of imaging studies based on specific clinical scenarios, which have been grouped into different variants. Each variant is accompanied by a brief description of the usefulness, advantages, and limitations of different imaging modalities. The present narrative is the result of an exhaustive assessment of the available literature and a thorough review process by a panel of experts on Musculoskeletal Imaging. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

The combination of an inflammatory peripheral blood gene expression and imaging biomarkers enhance prediction of radiographic progression in knee osteoarthritis.

OBJECTIVE: Predictive biomarkers of progression in knee osteoarthritis are sought to enable clinical trials of structure-modifying drugs. A peripheral blood leukocyte (PBL) inflammatory gene signature, MRI-based bone marrow lesions (BML) and meniscus extrusion scores, meniscal lesions, and osteophytes on X-ray each have been shown separately to predict radiographic joint space narrowing (JSN) in subjects with symptomatic knee osteoarthritis (SKOA). In these studies, we determined whether the combination of the PBL inflammatory gene expression and these imaging findings at baseline enhanced the prognostic value of either alone. METHODS: PBL inflammatory gene expression (increased mRNA for IL-1ß, TNFα, and COX-2), routine radiographs, and 3T knee MRI were assessed in two independent populations with SKOA: an NYU cohort and the Osteoarthritis Initiative (OAI). At baseline and 24 months, subjects underwent standardized fixed-flexion knee radiographs and knee MRI. Medial JSN (mJSN) was determined as the change in medial JSW. Progressors were defined by an mJSN cut-point (≥ 0.5 mm/24 months). Models were evaluated by odds ratios (OR) and area under the receiver operating characteristic curve (AUC). RESULTS: We validated our prior finding in these two independent (NYU and OAI) cohorts, individually and combined, that an inflammatory PBL inflammatory gene expression predicted radiographic progression of SKOA after adjustment for age, sex, and BMI. Similarly, the presence of baseline BML and meniscal lesions by MRI or semiquantitative osteophyte score on X-ray each predicted radiographic medial JSN at 24 months. The combination of the PBL inflammatory gene expression and medial BML increased the AUC from 0.66 (p = 0.004) to 0.75 (p < 0.0001) and the odds ratio from 6.31 to 19.10 (p < 0.0001) in the combined cohort of 473 subjects. The addition of osteophyte score to BML and PBL inflammatory gene expression further increased the predictive value of any single biomarker. A causal analysis demonstrated that the PBL inflammatory gene expression and BML independently influenced mJSN. CONCLUSION: The use of the PBL inflammatory gene expression together with imaging biomarkers as combinatorial predictive biomarkers, markedly enhances the identification of radiographic progressors. The identification of the SKOA population at risk for progression will help in the future design of disease-modifying OA drug trials and personalized medicine strategies.

Interleukin 1 receptor antagonist (IL1RN) gene variants predict radiographic severity of knee osteoarthritis and risk of incident disease.

OBJECTIVE: In these studies, we examined the association of single nucleotide polymorphisms (SNPs) of the IL1RN gene with radiographic severity of symptomatic knee osteoarthritis (SKOA) and the risk of incident OA. We also explored these genetic polymorphisms in patients with new onset rheumatoid arthritis (RA). METHODS: Over 1000 subjects who met American College of Rheumatology criteria for tibiofemoral OA were selected from three independent, National Institute of Health (NIH)-funded cohorts. CTA and TTG haplotypes formed from three SNPs of the IL1RN gene (rs419598, rs315952, rs9005) were assessed for association with radiographic severity, and risk for incident radiographic OA (rOA) in a nested case-control cohort. These IL1RN haplotypes were also assessed for association with disease activity (DAS28) and plasma inflammatory markers in patients with RA. RESULTS: Carriage of the IL1RN TTG haplotype was associated with increased odds of more severe rOA compared with age-matched, sex-matched and body mass index-matched individuals. Examination of the osteoarthritis initiative Incidence Subcohort demonstrated that carriage of the TTG haplotype was associated with 4.1-fold (p=0.001) increased odds of incident rOA. Plasma IL-1Ra levels were lower in TTG carriers, while chondrocytes from TTG carriers exhibited decreased secretion of IL-1Ra. In patients with RA, the TTG haplotype was associated with increased DAS28, decreased plasma IL-1Ra and elevations of plasma inflammatory markers (hsCRP, interleukin 6 (IL-6)). CONCLUSION: Carriage of the IL1RN TTG haplotype is associated with more severe rOA, increased risk for incident OA, and increased evidence of inflammation in RA. These data suggest that the IL1RN TTG risk haplotype, associated with decreased IL-1Ra plasma levels, impairs endogenous 'anti-inflammatory' mechanisms.

Vascular Adhesion Protein-1 (VAP-1) as Predictor of Radiographic Severity in Symptomatic Knee Osteoarthritis in the New York University Cohort.

BACKGROUND: To investigate the expression of vascular adhesion protein-1 (VAP-1) in joint tissues and serum in symptomatic knee osteoarthritis (SKOA) patients and examine whether VAP-1 levels predict increased risk of disease severity in a cross-sectional study. METHODS: Baseline VAP-1 expression and soluble VAP-1 (sVAP-1) levels were assessed in the synovium synovial fluid and in the serum in cohorts of patients with tibiofemoral medial knee OA and healthy subjects. Standardized fixed-flexion poster anterior knee radiographs scored for Kellgren-Lawrence (KL) grade (0-4) and medial joint space width (JSW). KL1/2 vs. KL3/4 scores defined early and advanced radiographic severity, respectively. Biochemical markers assessed in serum or synovial fluids (SF) comprised sVAP-1, interleukin 1 receptor antagonist (IL-1Ra), interleukin 6 (IL-6), soluble receptor for advanced glycation end-products (sRAGE), C-C motif chemokine ligand 2 (CCL2), C-C motif chemokine ligand 4 (CCL4), cluster of differentiation 163 (CD163), high sensitivity C-reactive protein (hsCRP), and matrix metalloproteinases (MMPs)-1,-3,-9. Associations between biomarkers and radiographic severity KL1/2 vs. KL3/4 (logistic regression controlling for covariates) and pain (Spearman correlation) were evaluated. RESULTS: Elevated levels of sVAP-1 observed in OA synovial fluid and VAP-1 expression in synovium based on immunohistochemical, microarray, and real-time quantitative polymerase chain reaction (qRT-PCR) analyses. However, serum sVAP-1 levels in OA patients were lower than in controls and inversely correlated with pain and inflammation markers (hsCRP and soluble RAGE). Soluble VAP-1 levels in serum were also lower in radiographically advanced (KL3/4) compared with early KL1/2 knee SKOA patients. CONCLUSION: Local (synovial fluid) semicarbazide-sensitive amine oxidase (SSAO)/sVAP-1 levels were elevated in OA and correlated with radiographic severity. However, systemic (serum) sVAP-1 levels were lower in SKOA patients than normal and inversely correlated with pain and inflammation markers. Serum sVAP-1 levels were higher in early (KL1/2) compared with advanced (KL3/4) SKOA patients.

Functional MR Neurography in Evaluation of Peripheral Nerve Trauma and Postsurgical Assessment.

Evaluation of traumatic peripheral nerve injuries has classically been based on clinical and electrophysiologic criteria. US and MRI have been widely used for morphologic assessment of nerve injury sites and concomitant lesions. In the past few years, morphologic MR neurography has significantly increased its clinical applications on the basis of three-dimensional or two-dimensional images with and without fat-suppression techniques. However, these sequences have a major drawback: absence of pathophysiologic information about functional integrity or axonal flow of peripheral nerves. In this scenario, functional MRI techniques such as diffusion-weighted imaging (DWI) or diffusion tensor imaging (DTI) can be used as a complementary tool in initial evaluation of peripheral nerve trauma or in assessment of trauma undergoing surgical repair. These approaches provide not only morphologic but also functional information about extent and degree of nerve impairment. Functional MR neurography can also be applied to selection, planning, and monitoring of surgical procedures that can be performed after traumatic peripheral nerve injuries, such as neurorrhaphy, nerve graft, or neurolysis, as it provides surgeons with valuable information about the functional status of the nerves involved and axonal flow integrity. The physical basis of DWI and DTI and the technical adjustments required for their appropriate performance for peripheral nerve evaluation are reviewed. Also, the clinical value of DWI and DTI in assessment of peripheral nerve trauma is discussed, enhancing their potential impact on selection, planning, and monitoring of surgical procedures employed for peripheral nerve repair. Online supplemental material is available for this article. ©RSNA, 2019.

Diffusion tensor imaging of articular cartilage using a navigated radial imaging spin-echo diffusion (RAISED) sequence.

OBJECTIVE: To validate a radial imaging spin-echo diffusion tensor (RAISED) sequence for high-resolution diffusion tensor imaging (DTI) of articular cartilage at 3 T. METHODS: The RAISED sequence implementation is described, including the used non-linear motion correction algorithm. The robustness to eddy currents was tested on phantoms, and accuracy of measurement was assessed with measurements of temperature-dependent diffusion of free water. Motion correction was validated by comparing RAISED with single-shot diffusion-weighted echo-planar imaging (EPI) measures. DTI was acquired in asymptomatic subjects (n = 6) and subjects with doubtful (Kellgren-Lawrence [KL] grade 1, n = 9) and mild (KL = 2, n = 9) symptomatic knee osteoarthritis (OA). MD and FA values without correction, and after all corrections, were calculated. A test-retest evaluation of the DTI acquisition on three asymptomatic and three OA subjects was also performed. RESULTS: The root mean squared coefficient of variation of the global test-restest reproducibility was 3.54% for MD and 5.34% for FA. MD was significantly increased in both femoral condyles (7-9%) of KL 1 and in the medial (11-17%) and lateral (10-12%) compartments of KL 2 subjects. Averaged FA presented a trend of lower values with increasing KL grade, which was significant for the medial femoral condyle (-11%) of KL 1 and all three compartments in KL 2 subjects (-18 to -11%). Group differences in MD and FA were only significant after motion correction. CONCLUSION: The RAISED sequence with the proposed reconstruction framework provides reproducible assessment of DTI parameters in vivo at 3 T and potentially the early stages of the disease in large regions of interest. KEY POINTS: • DTI of articular cartilage is feasible at 3T with a multi-shot RAISED sequence with non-linear motion correction. • RAISED sequence allows estimation of the diffusion indices MD and FA with test-retest errors below 4% (MD) and 6% (FA). • RAISED-based measurement of DTI of articular cartilage with non-linear motion correction holds potential to differentiate healthy from OA subjects.