Advanced Imaging of the Peripheral Nerves, From the AJR "How We Do It" Special Series.

Advanced imaging of peripheral nerves is occupying an increasingly important role in the diagnostic workup of peripheral nerve disorders. Advances in MR neurography (MRN) and high-resolution ultrasound have addressed historical challenges in peripheral nerve imaging related to nerves' small size and non-linear course, and difficult differentiation from surrounding tissues. Modern MRN depicts neuromuscular anatomy with exquisite contrast resolution, and MRN has become the workhorse imaging modality for peripheral nerve evaluation. MRN protocols vary across institutions and are adjusted in individual patients, although commonly include nerve-selective sequences and diffusion tensor imaging tractography. Ultrasound offers a dynamic, real-time high-resolution assessment of peripheral nerves, and is widely accessible and less costly than MRN. Ultrasound has greater ability to interrogate peripheral nerves at the fascicular level and provides complementary information to MRN. However, ultrasound of peripheral nerves requires substantial skill and experience and is operator-dependent. The two modalities have distinct advantages and disadvantages, and the selection between these depends on the clinical context. This article provides an overview of advanced imaging techniques used for evaluation of peripheral nerves, with attention to MRN and high-resolution ultrasound. We draw on our institutional experience in performing both modalities to highlight technical considerations for optimizing examinations.

Implementing treat-to-target urate-lowering therapy during hospitalisations for gout flares.

OBJECTIVES: To evaluate a strategy designed to optimise care and increase uptake of urate-lowering therapy (ULT) during hospitalisations for gout flares. METHODS: We conducted a prospective cohort study to evaluate a strategy that combined optimal in-hospital gout management with a nurse-led, follow-up appointment, followed by handover to primary care. Outcomes, including ULT initiation, urate target attainment, and re-hospitalisation rates, were compared between patients hospitalised for flares in the 12 months post-implementation and a retrospective cohort of hospitalised patients from 12 months pre-implementation. RESULTS: 119 and 108 patients, respectively, were hospitalised for gout flares in the 12 months pre- and post-implementation. For patients with 6-month follow-up data available (n = 94 and n = 97, respectively), the proportion newly initiated on ULT increased from 49.2% pre-implementation to 92.3% post-implementation (age/sex-adjusted odds ratio (aOR) 11.5; 95% confidence interval (CI) 4.36-30.5; p < 0.001). After implementation, more patients achieved a serum urate ≤360 micromol/L within 6 months of discharge (10.6% pre-implementation vs. 26.8% post-implementation; aOR 3.04; 95% CI 1.36-6.78; p = 0.007). The proportion of patients re-hospitalised for flares was 14.9% pre-implementation vs. 9.3% post-implementation (aOR 0.53, 95% CI 0.22 to 1.32; p = 0.18). CONCLUSION: Over 90% of patients were initiated on ULT after implementing a strategy to optimise hospital gout care. Despite increased initiation of ULT during flares, recurrent hospitalisations were not more frequent following implementation. Significant relative improvements in urate target attainment were observed post-implementation; however, for the majority of hospitalised gout patients to achieve urate targets, closer primary-secondary care integration is still needed.

Ultrasound-guided bursal injections.

The native bursa is a structure lined by synovium located adjacent to a joint which may serve to decrease friction between the tendons and overlying bone or skin. This extra-articular structure can become inflamed resulting in bursitis. Steroid injections have proven to be an effective method of treating bursal pathology in various anatomic locations. Performing these procedures requires a thorough understanding of relevant anatomy, proper technique, and expected outcomes. Ultrasound is a useful tool for pre procedure diagnostic evaluation and optimizing needle position during these procedures while avoiding adjacent structures. The purpose of this article is to review core principles of ultrasound-guided musculoskeletal procedures involving bursae throughout the upper and lower extremities.

Ultrasound-guided interventions of the upper extremity joints.

Ultrasound guidance is valuable for performing precise joint interventions. Joint interventions may be requested for therapeutic and diagnostic pain injections, joint aspiration in the setting of suspected infection, or contrast injection for arthrography. In practice, interventions of the shoulder girdle, elbow, and hand/wrist joints may be performed without any imaging guidance. However, imaging guidance results in more accurate interventions and better patient outcomes than those performed by palpation alone. When compared to other modalities used for imaging guidance, ultrasound has many potential advantages. Radiologists should be prepared to perform ultrasound-guided upper extremity joint interventions utilizing recommended techniques to optimize clinical practice and patient outcomes. KEY POINTS: 1. Ultrasound-guided injections of the glenohumeral, acromioclavicular, sternoclavicular, elbow, and hand/wrist joints have higher accuracy than injections performed without imaging guidance. 2. Ultrasound-guided aspirations of upper extremity joints have advantages to fluoroscopic-guided aspirations because of the potential to identify effusions, soft tissue abscess, or bursitis. 3. Ultrasound-guided contrast injection prior to MR arthrography is as accurate as fluoroscopic-guided injection for upper extremity joints.

Utilizing a Digital Swarm Intelligence Platform to Improve Consensus Among Radiologists and Exploring Its Applications.

Radiologists today play a central role in making diagnostic decisions and labeling images for training and benchmarking artificial intelligence (AI) algorithms. A key concern is low inter-reader reliability (IRR) seen between experts when interpreting challenging cases. While team-based decisions are known to outperform individual decisions, inter-personal biases often creep up in group interactions which limit nondominant participants from expressing true opinions. To overcome the dual problems of low consensus and interpersonal bias, we explored a solution modeled on bee swarms. Two separate cohorts, three board-certified radiologists, (cohort 1), and five radiology residents (cohort 2) collaborated on a digital swarm platform in real time and in a blinded fashion, grading meniscal lesions on knee MR exams. These consensus votes were benchmarked against clinical (arthroscopy) and radiological (senior-most radiologist) standards of reference using Cohen's kappa. The IRR of the consensus votes was then compared to the IRR of the majority and most confident votes of the two cohorts. IRR was also calculated for predictions from a meniscal lesion detecting AI algorithm. The attending cohort saw an improvement of 23% in IRR of swarm votes (k = 0.34) over majority vote (k = 0.11). Similar improvement of 23% in IRR (k = 0.25) in 3-resident swarm votes over majority vote (k = 0.02) was observed. The 5-resident swarm had an even higher improvement of 30% in IRR (k = 0.37) over majority vote (k = 0.07). The swarm consensus votes outperformed individual and majority vote decision in both the radiologists and resident cohorts. The attending and resident swarms also outperformed predictions from a state-of-the-art AI algorithm.

Impact of fatty degeneration on the functional outcomes of 38 patients undergoing surgical repair of gluteal tendon tears.

BACKGROUND: Gluteal tendon tears (GTT) can cause pain and weakness of the hip. We analyze the impact of gluteal muscle fatty degeneration, atrophy and tear morphology on clinical outcomes of surgical repair. METHODS: All sequential patients receiving surgical repair of GTTs via anchor sutures between 1/2015 and 11/2018 were retrospectively identified. MRIs were reviewed by a radiologist for tendon retraction, muscle atrophy and tear size. The Goutallier-Fuchs Classification (GFC) was used to quantify fatty degeneration as < 2° or ≥ 2°. Demographic and clinical variables were abstracted from the electronic records. The surveys HHS Section 1 and HOOS Jr. were obtained at last follow-up. The Pearson correlation and one-way ANOVA tests served for statistical analysis of clinical variance. RESULTS: 38 patients were identified, 29 (76.3%) were female. The average age was 67. Of the 11 (28.9%) patients with a prior hip arthroplasty 87.5% of primary THAs had a direct lateral approach. 29 (76.3%) patients were treated open and 9 (23.7%) arthroscopically. At an average follow-up of 20.9 months, patients reported a significant improvement in pain (97%), analgesic use (85.7%), limp (52.6%) and abduction strength (54.2%) (all: P ≤ 0.01). GFC ≥ 2° were associated with significantly worse outcomes in terms of limp (0.19/3 vs. 1.2/3, P = 0.05), HHS-S1 (58.19 vs. 71.68, P = 0.04) and complication rates (37.5% vs. 0%, P = 0.02). There was a strong correlation between tear retraction (P = 0.005), tear size (P = 0.009) and muscle atrophy (P = 0.001) with GFC ≥ 2° but not with clinical outcomes. GFC ≥ 2° was strongly related to lateral THA exposures (P < 0.001). Surgical approach had no impact on clinical outcomes. CONCLUSION: While fatty degeneration can negatively impact functional outcomes, pain relief is reliably achieved. Tear morphology and muscle atrophy did not correlate with outcomes in this patient cohort. Patients should be counseled to expect a residual limp after surgery if they have GFC ≥ 2° on MRI.

Problem Solved: Integral Applications of Musculoskeletal Ultrasound.

Musculoskeletal ultrasound has grown substantially in use over the past several years as an indispensable companion to magnetic resonance imaging and other imaging modalities. This article reviews 10 integral applications of musculoskeletal ultrasound as a problem-solving tool with correlative case examples. These applications include the following: (1) accessibility and portability, (2) targeted imaging, (3) dynamic imaging, (4) contralateral comparison, (5) Doppler imaging, (6) increased spatial resolution, (7) solid versus cystic comparison, (8) posttraumatic imaging, (9) postsurgical imaging, and (10) treatment delivery and optimization. The review will help the radiologist recognize the complementary uses of musculoskeletal ultrasound with radiography, computed tomography, and magnetic resonance imaging.

Diagnostic value of fluoroscopy-guided hip aspiration for periprosthetic joint infection.

PURPOSE: To assess the value of preoperative joint aspiration in detecting periprosthetic joint infection (PJI) in patients undergoing revision hip arthroplasty and to compare these with the clinical findings, serum markers, and intraoperative findings. MATERIALS AND METHODS: Fluoroscopically guided hip aspirations in patients with pain after hip arthroplasty were retrospectively reviewed from January 2014 to December 2018. All hips underwent subsequent revision hip arthroplasty. Antibiotics were discontinued at least 2 weeks before the aspiration. The 2018 Musculoskeletal Infection Society (MSIS) criteria served as a standard of reference for PJI. Clinical, serum, synovial, and intraoperative parameters were recorded in all patients. Correlations between all parameters with PJI diagnosis were analyzed using linear and logistic regression models with ROC analysis. RESULTS: In 202 hips that included 91 septic hips, hip aspiration (AUC = 0.78) and intraoperative (0.80) parameters performed better than serum-based tests (0.64) and clinical parameters (0.68) in detecting PJI. Using MSIS criteria as a standard of reference, hip aspiration had a sensitivity of 64.0% and an accuracy of 78.5% for cultures and a sensitivity of 74.2% and an accuracy of 82.1% for synovial polymorphonuclear neutrophils% (PMN%). Results substantially improved sensitivity after excluding patients that were treated with antibiotics, particularly culture results. CONCLUSIONS: Preoperative hip aspiration showed good diagnostic performance in diagnosing PJI compared with MSIS criteria as a standard of reference. But a negative result from aspirate could not rule out PJI. Based on our findings, hip aspiration is an essential test for treatment planning in patients with pain after hip arthroplasty.

Predicting outcomes in patients undergoing intra-articular corticosteroid hip injections.

OBJECTIVE: To investigate the associations between clinical, procedural, and radiographic factors and outcomes of steroid hip injections, including long-term and immediate pain reduction, time to arthroplasty, time to reinjection, and the total number of injections. MATERIALS AND METHODS: All intra-articular anesthetic and steroid injections of the hip under fluoroscopic guidance between January 2014 and March 2016 were retrospectively reviewed. Hip radiographs were scored using the Kellgren-Lawrence (KL) and Osteoarthritis Research Society International (OARSI) scores. Immediate pain relief and response were evaluated using a change in visual analog scale and OMERACT-OARSI criteria respectively. Long-term pain relief was evaluated at 2­7 months after injection by reviewing the medical records. Correlation between patient characteristics, procedural variations, and radiographic factors with injection outcomes was analyzed by using linear and logistic regression models. RESULTS: Of 361 injections, 79.8% showed an immediate pain response and 32.7% had subjective long-term pain relief (> 2 months). There was no significant correlation between immediate pain relief and response with long-term pain relief and other outcomes. Older age and higher KL score, OARSI-central joint space narrowing (JSN), and inferior acetabular osteophyte were correlated with long-term pain relief (p = 0.01­0.03). Higher KL and OARSI grades, particularly JSN, were significantly correlated with increased immediate pain relief and total number of injections but decreased time to arthroplasty. Baseline pain positively correlated with immediate pain response (p < 0.001). CONCLUSIONS: Older patients with higher grades of radiographic OA and high baseline pain were good candidates for steroid injections, particularly for those patients awaiting hip arthroplasty.

Equivalent Mid-Term Results of Open vs Endoscopic Gluteal Tendon Tear Repair Using Suture Anchors in Forty-Five Patients.

BACKGROUND: Little is known about the relative efficacy of open (OGR) vs endoscopic (EGR) gluteal tendon repair of gluteal tendon tears in minimizing pain and restoring function. Our aim is to compare these 2 surgical techniques and quantify their impact on clinical outcomes. METHODS: All patients undergoing gluteal tendon tear repair at our institution between 2015 and 2018 were retrospectively reviewed. Pain scores, limp, hip abduction strength, and the use of analgesics were recorded preoperatively and at last follow-up. The Hip disability and Osteoarthritis Outcome Score Junior and Harris Hip Score Section1 were obtained at last follow-up. Fatty degeneration was quantified using the Goutallier-Fuchs Classification (GFC). Statistical analysis was conducted using one-way analysis of variance and t-tests. RESULTS: Forty-five patients (mean age 66, 87% females) met inclusion criteria. Average follow-up was 20.3 months. None of the 10 patients (22%) undergoing EGR had prior surgery. Of 35 patients (78%) undergoing OGR, 12 (27%) had prior hip replacement (75% via lateral approach). The OGRs had more patients with GFC ≥2 (50% vs 11%, P = .02) and used more anchors (P = .03). Both groups showed statistical improvement (P ≤ .01) for all outcomes measured. GFC >2 was independently associated with a worst limp and Harris Hip Score Section 1 score (P = .05). EGR had a statistically higher opioid use reduction (P < .05) than OGR. Other comparisons between EGR and OGR did not reach statistical significance. CONCLUSION: In this series, open vs endoscopic operative approach did not impact clinical outcomes. More complex tears were treated open and with more anchors. Fatty degeneration adversely impacted outcomes. Although further evaluation of the efficacy of EGR in complex tears is indicated, both approaches can be used successfully.

Preoperative IDEAL (Iterative Decomposition of Echoes of Asymmetrical Length) magnetic resonance imaging rotator cuff muscle fat fractions are associated with rotator cuff repair outcomes.

BACKGROUND AND HYPOTHESIS: IDEAL (Iterative Decomposition of Echoes of Asymmetrical Length) imaging is a magnetic resonance imaging sequence that precisely measures rotator cuff muscle fatty infiltration. The influence of lower levels of fatty infiltration on outcomes after rotator cuff repair remains unclear. We hypothesized that increased preoperative fat fractions would be associated with inferior clinical outcomes after rotator cuff repair. METHODS: We retrospectively identified patients who underwent arthroscopic rotator cuff repair with preoperative IDEAL imaging. Patients completed the Patient-Reported Outcomes Measurement Information System (PROMIS) Upper Extremity computer adaptive survey at a minimum of 2 years after repair. Muscle segmentation was performed on 4 consecutive slices. Correlations between intramuscular fat fractions and PROMIS scores were determined. Patients were grouped by PROMIS scores of 50 or greater and scores lower than 50 for comparison of fat fractions. Multivariate linear regression was performed to model PROMIS scores as a function of demographic characteristics, tear size, and fat fractions. Significance was defined as P < .05. RESULTS: Eighty patients were included (mean follow-up, 42.5 ± 10.7 months). Postoperative PROMIS scores were significantly inversely correlated with the infraspinatus (ρ = -0.25, P = .02) and subscapularis (ρ = -0.29, P = .009) fat fractions. The infraspinatus (7.2% ± 4.9% vs. 5.2% ± 3.0%, P = .046) and subscapularis (10.4% ± 5.1% vs. 8.2% ± 5.0%, P = .001) fat fractions were significantly higher for patients with low PROMIS scores vs. those with PROMIS scores of 50 or greater. In multivariate modeling, the infraspinatus fat fraction (ß = -0.68, P = .029) was the only significant independent predictor of postoperative PROMIS score. CONCLUSION: Intramuscular fat as determined by quantitative magnetic resonance imaging is an important factor in postoperative outcomes even in patients with lower levels of preoperative fatty infiltration.

Management of sickle cell disease in patients undergoing cardiac surgery.

Sickle cell disease is a life-limiting inherited hemoglobinopathy that poses inherent risk for surgical complications following cardiac operations. In this review, we discuss preoperative considerations, intraoperative decision-making, and postoperative strategies to optimize the care of a patient with sickle cell disease undergoing cardiac surgery.

Online Learning in Medical Student Clerkship: A Survey of Student Perceptions and Future Directions.

Background The coronavirus disease 2019 (COVID-19) pandemic had a major impact on medical education with clerkship students abruptly removed from clinical activities in 2020 and hastily immersed in online learning to maintain medical education. In 2022, students returned to in-person clinical experiences, but synchronous learning sessions continued online with extensive use of asynchronous online resources. This change offers a unique opportunity to gather information about students' perspectives regarding the acceptability and effectiveness of online learning strategies. This study aims to explore the clerkship student experience with the integration of online learning and in-person learning into formalized educational sessions in clerkship. Methodology The authors administered an online survey to clerkship students at the Cumming School of Medicine at the University of Calgary, Canada in spring 2022. The survey consisted of primarily Likert-style questions to explore the perceived effectiveness of various online learning strategies. Results are reported as the proportion selecting "quite effective" or "extremely effective." Results A total of 89 students responded to the survey (57.4% of graduating class). For synchronous online learning, case-based learning was perceived as the most effective teaching strategy (61.8%), and audience response systems were the most effective strategy for improving audience engagement (70.1%). For asynchronous online learning, interactive cases (84.9%) and student-developed online study guides (83.6%) were perceived as the most effective. Students held varying perceptions regarding how online learning impacted their well-being. When considering future clerkship curricula, the majority of clerkship students preferred a blend of in-person and online learning. Conclusions This study identified that most clerkship students prefer a hybrid of in-person and online learning and that ideal online learning curricula could include case-based learning, audience response systems, and a variety of asynchronous learning resources. These results can guide curriculum development and design at other medical institutions.

Localized APP expression results in progressive network dysfunction by disorganizing spike timing.

Progressive cognitive decline in Alzheimer's disease could either be caused by a spreading molecular pathology or by an initially focal pathology that causes aberrant neuronal activity in a larger network. To distinguish between these possibilities, we generated a mouse model with expression of mutant human amyloid precursor protein (APP) in only hippocampal CA3 cells. We found that performance in a hippocampus-dependent memory task was impaired in young adult and aged mutant mice. In both age groups, we then recorded from the CA1 region, which receives inputs from APP-expressing CA3 cells. We observed that theta oscillation frequency in CA1 was reduced along with disrupted relative timing of principal cells. Highly localized pathology limited to the presynaptic CA3 cells is thus sufficient to cause aberrant firing patterns in postsynaptic neuronal networks, which indicates that disease progression is not only from spreading pathology but also mediated by progressively advancing physiological dysfunction.

Imaging of Overuse Injuries of the Hip.

Overuse injuries of the hip are common, and clinical diagnosis may be difficult because of overlapping and nonspecific clinical symptoms. Imaging can play an essential role in guiding diagnosis and management. Femoroacetabular joint structural abnormalities result in various conditions that can predispose patients to early development of osteoarthritis. Repetitive stress on the skeletally immature hip can result in apophyseal injuries. Notable nonosseous overuse hip pathologies include athletic pubalgia, trochanteric bursitis, and injuries involving the iliopsoas myotendinous unit. Timely diagnosis of overuse injuries of the hip can facilitate improved response to conservative measures and prevent irreversible damage.

Ovarian Vein Thrombosis: A Sequela of COVID-Associated Coagulopathy.

Coronavirus disease 2019 (COVID-19) causes endothelial damage, blood stasis, and an overall state of hypercoagulability. This makes COVID a huge risk factor for venous thromboembolism (VTE) and arterial thromboembolism (ATE). Twenty percent of COVID-19 patients suffer from coagulation abnormalities like pulmonary embolism, myocardial infarction, stroke, deep vein thrombosis, etc. Ovarian vein thrombosis (OVT) has been previously linked to post-partum period, pregnancy, hypercoagulable state, or malignancy. We analyzed PubMed and Google Scholar databases for research and publications regarding OVT in patients with COVID-19. The search yielded nine case reports. These case reports were found to implicate COVID-associated coagulopathy (CAC) as an additional risk factor for ovarian vein thrombosis (OVT). OVT most commonly presents with abdominal pain and fever, making it difficult to diagnose, owing to the similarity in presentation with multiple other pathologies. OVT can be diagnosed radiologically with ultrasound, magnetic resonance imaging (MRI) scan, or CT scan with IV contrast. CT has been used as the modality of choice for diagnosing OVT. Although rare, OVT can cause life-endangering complications by extension of thrombus into systemic veins or pulmonary artery embolization. Therefore, early diagnosis and treatment are vital. There is no official guideline for the treatment of OVT post-COVID. However, the literature supports the use of apixaban or enoxaparin/acenocoumarol.

Complete response to pembrolizumab in a patient with dermatomyositis and MMR deficient ovarian cancer: A case report.

•Immune checkpoint inhibitors can be safely administered to patients with dermatomyositis.•Immunosuppressants did not impact the efficacy of treatment with an immune check point inhibitor.•Patients with autoimmune disorders who require immune check point inhibitors should be monitored by a rheumatologist.

Clustered Incidence of Leukocytoclastic Vasculitis and Purpura Fulminans: A Case Series of a Rare Dermatological Manifestation of Rickettsial Disease.

Rickettsiae are a group of eukaryotic obligatory intracellular parasites with ticks and mites as vectors. Rickettsia conorii is the Indian counterpart of Rocky Mountain spotted fever causing the endemic variant - Indian tick typhus. This disease can cause severe illness in adults and children and can be missed despite the availability of serological tests. Initial screening for rickettsial diseases (RD) may include blood workup and a non-specific agglutination test, Weil-Felix (WF). In WF, agglutination against Proteus antigens is analyzed and can show false-negative results within the first week of presentation. Delayed immune reaction in patients with RD in the first week could also be responsible for negative specific IgM serology. The challenge for physicians is to differentiate between the two common diagnoses for fever with rash - viral exanthematous fever and rickettsial fever. By its endothelial cell tropism, RD rarely can lead to purpura fulminans, which is characterized by widespread progressive dermal vascular necrosis and hemorrhage. This case series demonstrates dermatologic presentations of rickettsial fever in three individuals from the same neighborhood within the same week. Based on serologic IgM levels, the patients were treated with doxycycline and made a full recovery. This case series aimed to highlight the need for awareness regarding the variable presentations of rickettsial fever including leukocytoclastic vasculitis and purpura fulminans.