MRI-based Neuropathy Score Reporting And Data System (NS-RADS): multi-institutional wider-experience usability study of peripheral neuropathy conditions among 32 radiology readers.

OBJECTIVE: To determine the inter-reader reliability and diagnostic performance of classification and severity scales of Neuropathy Score Reporting And Data System (NS-RADS) among readers of differing experience levels after limited teaching of the scoring system. METHODS: This is a multi-institutional, cross-sectional, retrospective study of MRI cases of proven peripheral neuropathy (PN) conditions. Thirty-two radiology readers with varying experience levels were recruited from different institutions. Each reader attended and received a structured presentation that described the NS-RADS classification system containing examples and reviewed published articles on this subject. The readers were then asked to perform NS-RADS scoring with recording of category, subcategory, and most likely diagnosis. Inter-reader agreements were evaluated by Conger's kappa and diagnostic accuracy was calculated for each reader as percent correct diagnosis. A linear mixed model was used to estimate and compare accuracy between trainees and attendings. RESULTS: Across all readers, agreement was good for NS-RADS category and moderate for subcategory. Inter-reader agreement of trainees was comparable to attendings (0.65 vs 0.65). Reader accuracy for attendings was 75% (95% CI 73%, 77%), slightly higher than for trainees (71% (69%, 72%), p = 0.0006) for nerves and comparable for muscles (attendings, 87.5% (95% CI 86.1-88.8%) and trainees, 86.6% (95% CI 85.2-87.9%), p = 0.4). NS-RADS accuracy was also higher than average accuracy for the most plausible diagnosis for attending radiologists at 67% (95% CI 63%, 71%) and for trainees at 65% (95% CI 60%, 69%) (p = 0.036). CONCLUSION: Non-expert radiologists interpreted PN conditions with good accuracy and moderate-to-good inter-reader reliability using the NS-RADS scoring system. CLINICAL RELEVANCE STATEMENT: The Neuropathy Score Reporting And Data System (NS-RADS) is an accurate and reliable MRI-based image scoring system for practical use for the diagnosis and grading of severity of peripheral neuromuscular disorders by both experienced and general radiologists. KEY POINTS: • The Neuropathy Score Reporting And Data System (NS-RADS) can be used effectively by non-expert radiologists to categorize peripheral neuropathy. • Across 32 different experience-level readers, the agreement was good for NS-RADS category and moderate for NS-RADS subcategory. • NS-RADS accuracy was higher than the average accuracy for the most plausible diagnosis for both attending radiologists and trainees (at 75%, 71% and 65%, 65%, respectively).

Neuropathy Score Reporting and Data System: A Reporting Guideline for MRI of Peripheral Neuropathy With a Multicenter Validation Study.

BACKGROUND. A standardized guideline and scoring system would improve evaluation and reporting of peripheral neuropathy (PN) on MRI. OBJECTIVE. The objective of this study was to create and validate a neuropathy classification and grading system, which we named the Neuropathy Score Reporting and Data System (NS-RADS). METHODS. This retrospective study included 100 patients with nerve imaging studies and known clinical diagnoses. Experts crafted NS-RADS using mutually agreed-on qualitative criteria for the classification and grading of PN. Different classes were created to account for the spectrum of underlying pathologies: unremarkable (U), injury (I), neoplasia (N), entrapment (E), diffuse neuropathy (D), not otherwise specified (NOS), and postintervention state (PI). Subclasses were established to describe the severity or extent of the lesions. Validation testing was performed by 11 readers from 10 institutions with experience levels ranging from 3 to 18 years after residency. After initial reader training, cases were presented to readers who were blinded to the final clinical diagnoses. Interobserver agreement was assessed using correlation coefficients and the Conger kappa, and accuracy testing was performed. RESULTS. Final clinical diagnoses included normal (n = 5), nerve injury (n = 25), entrapment (n = 15), neoplasia (n = 33), diffuse neuropathy (n = 18), and persistent neuropathy after intervention (n = 4). The miscategorization rate for NS-RADS classes was 1.8%. Final diagnoses were correctly identified by readers in 71-88% of cases. Excellent inter-reader agreement was found on the NS-RADS pathology categorization (κ = 0.96; 95% CI, 0.93-0.98) as well as muscle pathology categorization (κ = 0.76; 95% CI, 0.68-0.82). The accuracy for determining milder versus more severe categories per radiologist ranged from 88% to 97% for nerve lesions and from 86% to 94% for muscle abnormalities. CONCLUSION. The proposed NS-RADS classification is accurate and reliable across different reader experience levels and a spectrum of PN conditions. CLINICAL IMPACT. NS-RADS can be used as a standardized guideline for reporting PN and improved multidisciplinary communications.

Diaphragm and Phrenic Nerve Ultrasound in COVID-19 Patients and Beyond: Imaging Technique, Findings, and Clinical Applications.

The diaphragm, the principle muscle of inspiration, is an under-recognized contributor to respiratory disease. Dysfunction of the diaphragm can occur secondary to lung disease, prolonged ventilation, phrenic nerve injury, neuromuscular disease, and central nervous system pathology. In light of the global pandemic of coronavirus disease 2019 (COVID-19), there has been growing interest in the utility of ultrasound for evaluation of respiratory symptoms including lung and diaphragm sonography. Diaphragm ultrasound can be utilized to diagnose diaphragm dysfunction, assess severity of dysfunction, and monitor disease progression. This article reviews diaphragm and phrenic nerve ultrasound and describes clinical applications in the context of COVID-19.

Neuropathy Score Reporting and Data System (NS-RADS): MRI Reporting Guideline of Peripheral Neuropathy Explained and Reviewed.

A standardized guideline and scoring system should be used for the MR imaging diagnosis of peripheral neuropathy. The MR imaging-based Neuropathy Score Reporting and Data System (NS-RADS) is a newly devised classification system (in press in AJR) that can be used to communicate both type and severity of peripheral neuropathy in the light of clinical history and examination findings. The spectrum of neuropathic conditions and peripheral nerve disorders covered in this system includes nerve injury, entrapment, neoplasm, diffuse neuropathy, and post-interventional states. This classification system also describes the temporal MR imaging appearances of regional muscle denervation changes. This review article is based on the multicenter validation study pre-published in American journal of Roentgenology and discusses technical considerations of optimal MR imaging for peripheral nerve evaluation and discusses the NS-RADS classification and its severity scales with illustration of conditions that fall under each classification. The readers can gain knowledge of the NS-RADS classification system and learn to apply it in their practices for improved inter-disciplinary communications and timely patient management.

The distribution of acquired peripheral nerve injuries associated with severe COVID-19 implicate a mechanism of entrapment neuropathy: a multicenter case series and clinical feasibility study of a wearable, wireless pressure sensor.

We diagnosed 66 peripheral nerve injuries in 34 patients who survived severe coronavirus disease 2019 (COVID-19). We combine this new data with published case series re-analyzed here (117 nerve injuries; 58 patients) to provide a comprehensive accounting of lesion sites. The most common are ulnar (25.1%), common fibular (15.8%), sciatic (13.1%), median (9.8%), brachial plexus (8.7%) and radial (8.2%) nerves at sites known to be vulnerable to mechanical loading. Protection of peripheral nerves should be prioritized in the care of COVID-19 patients. To this end, we report proof of concept data of the feasibility for a wearable, wireless pressure sensor to provide real time monitoring in the intensive care unit setting.

Imaging Review of Peripheral Nerve Injuries in Patients with COVID-19.

With surging numbers of patients with coronavirus disease 2019 (COVID-19) throughout the world, neuromuscular complications and rehabilitation concerns are becoming more apparent. Peripheral nerve injury can occur in patients with COVID-19 secondary to postinfectious inflammatory neuropathy, prone positioning-related stretch and/or compression injury, systemic neuropathy, or nerve entrapment from hematoma. Imaging of peripheral nerves in patients with COVID-19 may help to characterize nerve abnormality, to identify site and severity of nerve damage, and to potentially elucidate mechanisms of injury, thereby aiding the medical diagnosis and decision-making process. This review article aims to provide a first comprehensive summary of the current knowledge of COVID-19 and peripheral nerve imaging.

Ultrasound-Guided Lateral Abdominal Wall Botulinum Toxin Injection Before Ventral Hernia Repair: A Review for Radiologists.

Preoperative ultrasound-guided lateral abdominal wall botulinum toxin injection is a promising method for improving patient outcomes and reducing recurrence rates after ventral hernia repair. A review of the literature demonstrates variability in the procedural technique, without current standardization of protocols. As radiologists may be increasingly asked to perform ultrasound-guided botulinum toxin injections of the lateral abdominal wall, familiarity with the procedure and current literature is necessary.

Diagnostic contribution of contrast-enhanced 3D MR imaging of peripheral nerve pathology.

OBJECTIVE: To assess the diagnostic contribution of contrast-enhanced 3D STIR (ce3D-SS) high-resolution magnetic resonance (MR) imaging of peripheral nerve pathology relative to conventional 2D sequences. MATERIALS AND METHODS: In this IRB-approved retrospective study, two radiologists reviewed 60 MR neurography studies with nerve pathology findings. The diagnostic contribution of ce3D-SS imaging was scored on a 4-point Likert scale (1 = no additional information, 2 = supports interpretation, 3 = moderate additional information, and 4 = diagnosis not possible without ce3D-SS). Image quality, nerve visualization, and detection of nerve pathology were also assessed for both standard 2D neurography and ce3D-SS sequences utilizing a 3-point Likert scale. Descriptive statistics are reported. RESULTS: The diagnostic contribution score for ce3D-SS imaging was 2.25 for the brachial plexus, 1.50 for extremities, and 1.75 for the lumbosacral plexus. For brachial plexus, the mean consensus scores for image quality, nerve visualization, and detection of nerve pathology were 2.55, 2.5, and 2.55 for 2D and 2.35, 2.45, and 2.45 for 3D. For extremities, the mean consensus scores for image quality, nerve visualization, and detection of nerve pathology were 2.60, 2.80, and 2.70 for 2D and 1.8, 2.20, and 2.10 for 3D. For lumbosacral plexus, the mean consensus scores for image quality, nerve visualization, and detection of nerve pathology were 2.45, 2.75, and 2.65 for 2D and 2.0, 2.45, and 2.25 for 3D. CONCLUSION: Overall, our study supports the potential application of ce3D-SS imaging for MRN of the brachial plexus but suggests that 2D MRN protocols are sufficient for MRN of the extremities and lumbosacral plexus.

Musculoskeletal involvement of COVID-19: review of imaging.

The global pandemic of coronavirus disease 2019 (COVID-19) has revealed a surprising number of extra-pulmonary manifestations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. While myalgia is a common clinical feature of COVID-19, other musculoskeletal manifestations of COVID-19 were infrequently described early during the pandemic. There have been emerging reports, however, of an array of neuromuscular and rheumatologic complications related to COVID-19 infection and disease course including myositis, neuropathy, arthropathy, and soft tissue abnormalities. Multimodality imaging supports diagnosis and evaluation of musculoskeletal disorders in COVID-19 patients. This article aims to provide a first comprehensive summary of musculoskeletal manifestations of COVID-19 with review of imaging.

Anatomy, Imaging, and Pathologic Conditions of the Brachial Plexus.

The brachial plexus is an intricate anatomic structure with an important function: providing innervation to the upper extremity, shoulder, and upper chest. Owing to its complex form and longitudinal course, the brachial plexus can be challenging to conceptualize in three dimensions, which complicates evaluations in standard orthogonal imaging planes. The components of the brachial plexus can be determined by using key anatomic landmarks. Applying this anatomic knowledge, a radiologist should then be able to identify pathologic appearances of the brachial plexus by using imaging modalities such as MRI, CT, and US. Brachial plexopathies can be divided into two broad categories that are based on disease origin: traumatic and nontraumatic. In the traumatic plexopathy group, there are distinct imaging findings and management methods for pre- versus postganglionic injuries. For nontraumatic plexopathies, having access to an accurate patient history is often crucial. Knowledge of the timing of radiation therapy is critical to diagnosing post-radiation therapy brachial plexopathy. In acute brachial neuritis, antecedent stressors occur within a specific time frame. Primary and secondary tumors of the brachial plexus are not uncommon, with the most common primary tumors being peripheral nerve sheath tumors. Direct extension and metastasis from primary malignancies such as breast and lung cancer can occur. Although diagnosing a brachial plexus anomaly is potentially perplexing, it can be straightforward if it is based on foundational knowledge of anatomy, imaging findings, and pathologic features. ©RSNA, 2020.

With or without? A retrospective analysis of intravenous contrast utility in magnetic resonance neurography.

OBJECTIVE: To determine the utility of intravenous contrast in magnetic resonance neurography (MRN). MATERIALS AND METHODS: A search of our PACS for MRN studies performed in 2015 yielded 74 MRN exams, 57 of which included pre- and post-contrast images. All studies were independently reviewed by 3 musculoskeletal radiologists with peripheral nerve imaging experience for presence/absence of nerve pathology, presence/absence of muscle denervation, and contrast utility score based on a 4-point Likert scale. The medical record was reviewed for demographic and clinical data. RESULTS: The mean contrast utility score across all readers and all cases was 1.65, where a score of 1 indicated no additional information and a score of 2 indicated mild additional information/supports interpretation. The mean contrast utility score was slightly higher in cases with a clinical indication of amputation/stump neuroma or mass (2.3 and 2.1 respectively) and lower in cases with a clinical indication of trauma (1.5). The mean contrast utility score was lowest in patients undergoing MRN for pain, numbness, and/or weakness (1.2). CONCLUSION: Intravenous contrast provides mild to no additional information for the majority of MRN exams. Given the invasive nature of contrast and recent concerns regarding previously unrecognized risks of repetitive contrast exposure, assessment of the necessity of intravenous contrast in MRN is important. Consensus evidence-based practice guidelines regarding intravenous contrast use in MRN are necessary.

Imaging of Hip Arthroplasties: Normal Findings and Hardware Complications.

Hip arthroplasty is a common and largely successful surgical procedure, often used for the treatment of advanced osteoarthritis. Imaging plays a key role in routine postoperative imaging surveillance as well as the evaluation of post-arthroplasty pain. Radiographs are the first-line imaging modality and may be followed by computed tomography (CT), ultrasound, and/or magnetic resonance imaging (MRI). Recent advancements in imaging techniques allow for metal artifact reduction on CT and MRI. A variety of complications can arise in the setting of arthroplasty: mechanical loosening, component wear-induced synovitis and osteolysis, adverse local tissue reaction, infection, periprosthetic fracture, implant dislocation and/or component displacement, tendinopathy, and neurovascular injury. This article reviews normal and abnormal imaging findings of hip arthroplasty.

Magnetic resonance neurography of traumatic pediatric peripheral nerve injury: beyond birth-related brachial palsy.

Traumatic peripheral nerve injury occurs more frequently in the pediatric population than previously recognized. High-resolution magnetic resonance (MR) imaging in the form of MR neurography can serve as a powerful noninvasive tool for detecting and characterizing peripheral nerve injury in children. In this review article we briefly discuss optimal methods of MR neurography image acquisition, highlighting core MR sequences necessary to characterize peripheral nerve injury. In addition, we illustrate the MR neurography appearance of normal and abnormal peripheral nerves in children, with emphasis on commonly used Seddon and Sunderland classification schemes to characterize peripheral nerve injury severity. The primary and secondary features associated with peripheral nerve injury including skeletal muscle denervation are reviewed in addition to key distinctive features that can impact operative versus nonoperative management of children. We include a checklist approach to interpreting MR neurography for the assessment of peripheral nerve injury.

High-resolution ultrasound of the fascia lata iliac crest attachment: anatomy, pathology, and image-guided treatment.

Pathology of the fascia lata attachment at the iliac crest (FLAIC) is an under-recognized and often misdiagnosed cause of lateral hip pain. The fascia lata has a broad attachment at the lateral iliac crest with contributions from the tensor fascia lata muscle, the iliotibial band, and the gluteal aponeurosis. The FLAIC is susceptible to overuse injuries, acute traumatic injuries, and degeneration. There is a paucity of literature regarding imaging and image-guided treatment of the FLAIC. We review anatomy and pathology of the FLAIC, presenting novel high-resolution (18-24 MHz) ultrasound images including ultrasound guidance for targeted therapeutic treatment.

Initial experience with dual-energy computed tomography-guided bone biopsies of bone lesions that are occult on monoenergetic CT.

OBJECTIVE: Our purpose was to determine whether dual-energy CT (DECT), specifically the bone marrow setting of the virtual noncalcium (VNCa) algorithm, could be used to identify and accurately biopsy suspected bone malignancies that were visible on magnetic resonance imaging (MRI), nuclear bone scintigraphy, or positron-emission tomography/computed tomography (PET/CT), but occult on monoenergetic computed tomography (CT) by virtue of being either isodense or nearly isodense to surrounding normal bone. MATERIALS AND METHODS: We present 4 cases in which DECT was used to detect various malignant bone lesions and was successfully used to direct percutaneous DECT-guided bone biopsies. RESULTS: Two of the lesions were solid tumor metastases (breast and prostate carcinoma), whereas two others were hematological malignancies (leukemia and lymphoma). This technique enabled us to confidently and accurately direct the biopsy needle into the target lesion. CONCLUSION: The authors demonstrate that the DECT VNCa bone marrow algorithm may be helpful in identifying isodense bone lesions of various histologies and may be used to guide percutaneous bone biopsies. This technique may help to maximize diagnostic yield, minimize the number of passes into the region of concern, and prevent patients from undergoing repeat biopsy.

Pins and Needles From Fingers to Toes: High-Resolution MRI of Peripheral Sensory Mononeuropathies.

OBJECTIVE: The purpose of this article is to review advanced MRI techniques and describe the MRI findings of pure sensory mononeuropathy with relevant clinical and anatomic correlation. CONCLUSION: Peripheral sensory mononeuropathy can be challenging to evaluate with MRI because of the small caliber of pure sensory nerves and the lack of changes in secondary muscular denervation. Advances in MRI afford the necessary signal-intensity contrast and resolution for adequate evaluation of many of these small peripheral nerves.

MR neurography (MRN) of the long thoracic nerve: retrospective review of clinical findings and imaging results at our institution over 4 years.

OBJECTIVE: Long thoracic nerve (LTN) injury can result in ipsilateral serratus anterior palsy and scapular winging. Traditional means of evaluating patients with suspected LTN injury include physical examination and electrodiagnostic studies. The purpose of our study is to describe high-resolution magnetic resonance (MR) findings in patients with clinical suspicion of LTN neuropathy. METHODS: In this HIPAA-compliant, IRB-approved, retrospective study, two radiologists reviewed MR imaging performed for long thoracic neuropathy. Clinical presentation, electrodiagnostic studies and MR imaging of 20 subjects [mean age 37 ± 13 years; 25% (5/20) female] were reviewed. Observers reviewed MR imaging for LTN signal intensity, size, course, presence or absence of mass and secondary findings [skeletal muscle denervation (serratus anterior, trapezius, rhomboid) and scapular winging]. Descriptive statistics were reported. RESULTS: Clinical indications included trauma (n = 5), hereditary neuropathy (n = 1), pain (n = 8), winged scapula (n = 6), brachial plexitis (n = 4) and mass (n = 1). Electrodiagnostic testing (n = 7) was positive for serratus anterior denervation in three subjects. Abnormal LTN signal intensity, size, course or mass was present in 0/20. Secondary findings included skeletal muscle denervation in the serratus anterior in 40% (8/20), trapezius in 20% (4/20) and rhomboid in 20% (4/20). In 5% (1/20), an osteochondroma simulated a winged scapula, and in 2/20 (10%) MR showed scapular winging. CONCLUSIONS: High-resolution MR imaging is limited in its ability to visualize the long thoracic nerve directly, but does reveal secondary signs that can confirm a clinical suspicion of LTN injury.

Total anomalous pulmonary venous connection in a neonate characterised by low-dose, high-pitch cardiac CT.

We describe the use of low-dose dual-source cardiac for the evaluation of a neonate with suspected total anomalous pulmonary venous connection. This novel technique obviates the need for sedation or breathholding. Radiation dose-reduction strategies result in sub-mSv-estimated effective doses, substantially lower than annual background radiation dose. Low-dose, high-pitch cardiac CT should be considered as an alternative to MRI or diagnostic cardiac catheterisation in neonates with complex CHD, requiring definitive anatomic evaluation.