Ultrasound of peripheral nerve injury.

Nerve injury in children is important to recognize early given the greater chance for recovery. Both children and adults have better outcomes the sooner nerve injuries are recognized and repaired. Children have even better functional results after surgical repair, thought to be related to their neural plasticity. Ultrasound is a powerful diagnostic tool for grading and mapping peripheral nerve injury and is complementary to electromyography and nerve conduction studies. Nerve injuries can be classified into low and high grade with ultrasound adding essential prognostic information and aiding in patient management. High-grade nerve injuries likely require surgical intervention. This article will review nerve anatomy and injury grading systems that radiologists can learn quickly in order to accurately communicate with their clinical partners. A practical approach to describe the sonographic appearance of nerve injury will be discussed. This article will show radiologists how the added value of ultrasound for peripheral nerve injury can directly affect clinical management.

Musculoskeletal Manifestations of COVID-19: Currently Described Clinical Symptoms and Multimodality Imaging Findings.

COVID-19, the clinical syndrome produced by infection with SARS-CoV-2, can result in multisystem organ dysfunction, including respiratory failure and hypercoagulability, which can lead to critical illness and death. Musculoskeletal (MSK) manifestations of COVID-19 are common but have been relatively underreported, possibly because of the severity of manifestations in other organ systems. Additionally, patients who have undergone sedation and who are critically ill are often unable to alert clinicians of their MSK symptoms. Furthermore, some therapeutic measures such as medications and vaccinations can worsen existing MSK symptoms or cause additional symptoms. Symptoms may persist or occur months after the initial infection, known as post-COVID condition or long COVID. As the global experience with COVID-19 and the vaccination effort increases, certain patterns of MSK disease involving the bones, muscles, peripheral nerves, blood vessels, and joints have emerged, many of which are likely related to a hyperinflammatory host response, prothrombotic state, or therapeutic efforts rather than direct viral toxicity. Imaging findings for various COVID-19-related MSK pathologic conditions across a variety of modalities are being recognized, which can be helpful for diagnosis, treatment guidance, and follow-up. The online slide presentation from the RSNA Annual Meeting is available for this article. ©RSNA, 2022.

Pediatric solid intra-articular masses of the knee: prevalence, imaging features and etiologies.

BACKGROUND: The etiologies of pediatric solid intra-articular soft-tissue masses are not well described and can present diagnostic dilemmas. OBJECTIVE: Our hypothesis was that these entities have a limited differential diagnosis and are mostly benign. MATERIALS AND METHODS: We reviewed knee magnetic resonance imaging (MRI) scans performed at our tertiary care institution between 2001 and 2019 (n=3,915). Our inclusion criterion was knee MRI with a solid intra-articular soft-tissue mass. Our exclusion criteria were cases with no masses or non-solid intra-articular lesions with clear radiologic diagnoses. Multiple radiologic characteristics were evaluated. Radiologic and histological diagnoses were collected when available. Cases without histology were assigned a suspected diagnosis. RESULTS: Twenty-five out of 3,915 (<1%) cases met the inclusion/exclusion criteria. Twenty patients underwent biopsy. Patient age ranged from 1 to 19 years with a mean age of 12 years. Lesion size ranged from 1 to 7 cm with a mean of 3.3 cm. The top three histological diagnoses were pigmented villonodular synovitis (PVNS) (7/20, 35%), vascular malformations (2/20, 10%) and inflammatory arthritis (2/20, 10%). There was one malignant case of synovial sarcoma (1/20, 5%). Of the five cases without biopsies, PVNS was the most common diagnosis (3/5, 60%). Five out of 10 (50%) PVNS cases were focal and 5/10 (50%) were multifocal. All PVNS cases (10/10, 100%) had hypointense signal on T2. CONCLUSION: Solid intra-articular soft-tissue masses of the knee in children are rare, with a prevalence of <1% in our study. The vast majority are benign with PVNS being the most common diagnosis.

Pediatric discoid meniscus: can magnetic resonance imaging features coupled with clinical symptoms predict the need for surgery?

BACKGROUND: Magnetic resonance imaging (MRI) criteria for evaluating discoid meniscus is limited in the pediatric population. OBJECTIVE: To assess MRI features of intact discoid meniscus and correlate with clinical outcomes. MATERIALS AND METHODS: In this institutional review board (IRB)-approved retrospective cohort study, knee MRIs at our institution from 2008 to 2019 were reviewed. The inclusion criterion was diagnosis of discoid meniscus on MRI. Exclusion criteria were torn discoid meniscus at presentation, previous meniscal surgery and confounding knee conditions. MRI features of discoid meniscus collected were craniocaudal dimension, transverse dimension, transverse dimension to tibial plateau (TV:TP) ratio and increased intrameniscal signal. The clinical course was reviewed for knee pain, mechanical symptoms and treatment type. RESULTS: Two hundred and nineteen of 3,277 (6.7%) patients had discoid meniscus. Of the 219 patients, 71 (32.4%) satisfied inclusion criteria. Seven patients had discoid meniscus of both knees resulting in 78 discoid menisci. The average patient age was 11.1 years (min: 2.0, max: 17.0). The average follow-up was 30.6 months. Of the 78 discoid menisci, 14 (17.9%) required surgery. Increased intrameniscal signal was found more in discoid meniscus requiring surgery (surgical: 10/14, nonsurgical: 19/64, P=0.009). Surgically treated discoid meniscus had a statistically significant increase in transverse dimension (surgical: 18.3±5.0 mm, nonsurgical: 15.7±4.3 mm, P=0.045) and TV:TP ratio (surgical: 0.55±0.15, nonsurgical: 0.47±0.12, P=0.036). Mechanical symptoms (surgical: 9/11, nonsurgical: 21/60, P=8.4×10-6) and pain ≥1 month (surgical: 11/11, nonsurgical: 17/60, P=0.006) were found more often in surgical patients. Clinical and imaging criteria of mechanical symptoms and knee pain ≥1 month and at least one of (1) increased intrameniscal signal or (2) TV:TP ratio greater than 0.47 identified discoid menisci that developed a tear and/or required surgery with a sensitivity of 0.86 and specificity of 0.88. CONCLUSION: Mechanical symptoms and knee pain ≥1 month, and at least one of (1) increased intrameniscal signal or (2) TV:TP ratio greater than or equal to 0.47, identified discoid menisci that would go on to tear and/or require surgery with a sensitivity and specificity of 0.86 and 0.88, respectively.

Quantitative magnetic resonance imaging for determining bone marrow fat fraction at 1.5 T and 3.0 T: a technique to noninvasively assess cellularity and potential malignancy of the bone marrow.

BACKGROUND: Pediatric bone marrow assessment by MRI is challenging and primarily experiential and qualitative, with a paucity of clinically useful quantitative imaging techniques. OBJECTIVE: MRI fat fraction (MRI-FF) is a technique used to quantify the degree of fat in other organ systems. The purpose of this study was to assess whether MRI-FF accurately measures bone marrow composition. MATERIALS AND METHODS: This two-part study included a validation phase, followed by an application phase. For the validation phase, the MRI-FF of piglet bones (6 long bones, 8 axial bones) was performed at 1.5 tesla (T) and 3.0 T, and correlated to the histological fat fraction (H-FF). We used Bland-Altman plots to compare MRI-FF at 1.5 tesla T and 3.0 T. For the application phase, five children with malignant marrow disease were recruited along with seven age- and gender-matched control subjects. The MRI-FF in the children was correlated to the H-FF. Boxplots were used to compare the MRI-FF of patients and control subjects. RESULTS: For the validation animal study, the MRI-FF of piglet bones at both 1.5 T and 3.0 T demonstrated moderate positive correlation to H-FF (r=0.41 and 0.42, respectively). MRI-FF at 1.5 T and 3.0 T were in good agreement, on average 7.7% apart. For the application phase, we included 5 children (4 with leukemia, 1 rhabdomyosarcoma) with median age 7 years, range (3-10 years). All children had MRI-FF and H-FF below 10%. The MRI-FF in patients (3.8±1.2) was significantly lower than that of control subjects (46.1±12.3%) (P<0.01). CONCLUSION: MRI-FF is a valid technique to assess bone marrow fat fraction at both 1.5 T and 3.0 T. The MRI-FF in children with malignant marrow processes is significantly lower than in control subjects with normal marrow.

Physeal separation in pediatric osteomyelitis.

In children, acute osteomyelitis, an infection of the bone, is most commonly hematogeneous in origin. Osteomyelitis is most often diagnosed with magnetic resonance imaging (MRI) and findings may include marrow signal changes on T1 and T2, with abnormal enhancement after gadolinium. Imaging helps detect any associated intraosseous or subperiosteal abscesses, which may require orthopedic drainage. In this pictorial essay, we demonstrate the association of acute pediatric osteomyelitis with physeal separation, resulting in what may be confused for simple trauma, although there was no known history of trauma in any of the cases we researched. All of the cases had a large subperiosteal fluid collection with marked separation of the epiphysis from the metaphysis. It is important to recognize this potential association in osteomyelitis, as it is readily visible by radiographs and may lead to diagnostic uncertainty.

MRI characterization of brown adipose tissue under thermal challenges in normal weight, overweight, and obese young men.

PURPOSE: To implement quantitative Dixon magnetic resonance imaging (MRI) methods for brown adipose tissue (BAT) characterization at inactive and cold-activated states in normal weight, overweight, and obese subjects. The hypotheses are that MRI characteristics of BAT would differentiate between nonobese and obese subjects, and activation of BAT in response to thermal challenges that are detected by MRI would be correlated with BAT activity measured by positron emission tomography / computed tomography (PET/CT). MATERIALS AND METHODS: Fifteen male subjects (20.7 ± 1.5 years old) including six normal weight, five overweight, and four obese subjects participated in the study. A multiecho Dixon MRI sequence was performed on a 1.5T scanner. MRI was acquired under thermoneutral, nonshivering thermogenesis, and subsequent warm-up conditions. Fat fraction (FF), R2*, and the number of double bonds (ndb) were measured by solving an optimization problem that fits in- and out-of-phase MR signal intensities to the fat-water interference models. Imaging acquisition and postprocessing were performed by two MRI physicists. In each subject, Dixon MRI measurements of FF, R2*, and ndb were calculated for each voxel within all BAT regions of interest (ROIs) under each thermal condition. Mean FF, R2*, and ndb were compared between nonobese (ie, normal-weight/overweight) and obese subjects using the two-sample t-test. Receiver operating characteristic (ROC) analyses were performed to differentiate nonobese vs. obese subjects. BAT MRI measurement changes in response to thermal condition changes were compared with hypermetabolic BAT volume/activity measured by PET/CT using the Pearson's correlation. In addition, BAT MRI measurements were compared with body adiposity using the Pearson's correlation. P < 0.05 was considered statistically significant. RESULTS: Obese subjects showed higher FF and lower R2* than nonobese subjects under all three thermal conditions (P < 0.01). ROC analyses demonstrated that FF and R2* were excellent predictors for the differentiation of nonobese from obese subjects (100% specificity and 100% sensitivity). FF changes under thermal challenges were correlated with hypermetabolic BAT volume (r = -0.55, P = 0.04 during activation, and r = 0.72, P = 0.003 during deactivation), and with BAT activity (r = 0.69, P = 0.006 during deactivation), as measured by PET/CT. FF and R2* under all three thermal conditions were highly correlated with body adiposity (P ≤ 0.002). CONCLUSION: MRI characteristics of BAT differentiated between nonobese and obese subjects in both inactivated and activated states. BAT activation detected by Dixon MRI in response to thermal challenges were correlated with glucose uptake of metabolically active BAT. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:936-947.

ACR Appropriateness Criteria® Soft Tissue Vascular Anomalies: Vascular Malformations and Infantile Vascular Tumors (Non-CNS)-Child.

Soft tissue vascular anomalies may be composed of arterial, venous, and/or lymphatic elements, and diagnosed prenatally or later in childhood or adulthood. They are divided into categories of vascular malformations and vascular tumors. Vascular malformations are further divided into low-flow and fast-flow lesions. A low-flow lesion is most common, with a prevalence of 70%. Vascular tumors may behave in a benign, locally aggressive, borderline, or malignant manner. Infantile hemangioma is a vascular tumor that presents in the neonatal period and then regresses. The presence or multiple skin lesions in an infant can signal underlying visceral vascular anomalies, and complex anomalies may be associated with overgrowth syndromes. 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 process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Unusual Presentation of Pediatric Scurvy: A Necrotic Gastrostomy Tube Site in a 14-Year-Old Boy.

BACKGROUND Despite being considered a disease of the past, pediatric scurvy is increasingly reported in developed countries, especially among children with autism spectrum disorder, developmental delays, or a restrictive diet. Pediatric patients typically present with lower extremity pain or refusal to walk. This case study features an atypical presentation of scurvy in a non-ambulatory patient. CASE REPORT A 14-year-old boy with arthrogryposis multiplex congenita displayed a late-stage scurvy symptom: a necrotic gastrostomy tube site, indicative of poor wound healing due to vitamin C deficiency. The usual telltale symptoms of scurvy were camouflaged due to his non-ambulatory status, which may have contributed to a delayed presentation. Nevertheless, a comprehensive clinical evaluation, incorporating diet history, gingival symptoms, petechiae, and characteristic radiological signs, eventually led to the correct diagnosis. Although acute osteomyelitis was initially suspected, it was subsequently ruled out. Upon initiation of vitamin C therapy, the patient's symptoms subsided within a few days, and the necrotic tissue surrounding the gastrostomy tube healed completely within two weeks. CONCLUSIONS The highlighted case underscores the importance of including scurvy in the differential diagnosis for pediatric patients with lower extremity pain without fever. A detailed dietary history focusing on vitamin C intake is crucial during clinical evaluation. Early initiation of vitamin C therapy, when scurvy is suspected, may prevent unnecessary and extensive diagnostic workup for other potential causes, offering timely relief to the patient.

Pediatric Vascular Malformations: Imaging Guidelines and Recommendations.

Vascular malformations are commonly encountered in the pediatric population. This article reviews the imaging appearances of simple and syndromic vascular malformations in infants and children that radiologists should know and provides imaging guidelines based on an evidence-based approach. Malformations are discussed within the framework of the International Society for the Study of Vascular Anomalies classification system.

Tufted Angioma of the Index Finger Middle Phalanx.

A tufted angioma is a benign vascular tumor of the skin and subcutaneous tissue that classically presents as a violaceous nodule on the trunk or extremities in early childhood. Tufted angiomas of the finger are uncommon, and intraosseous involvement of these tumors is exceedingly rare. When present in the bone, these lesions may be difficult to distinguish from the more common pediatric condition of osteomyelitis or osteoid osteoma. We present the clinical, radiographic, and histopathologic findings for a unique case of a tufted angioma with intraosseous involvement in the middle phalanx treated by surgical excision and curettage with preservation of function.

Minimally Invasive Treatment for Unicameral Bone Cysts with Chemical Sclerosis and Bone Graft Substitute: A Preliminary Report.

PURPOSE: Unicameral bone cysts (UBCs) are benign lesions that primarily occur in childhood and can present with pain, pathologic fracture and growth disturbances. Existing treatment approaches for the management of UBCs are highly variable and recurrence is not uncommon. This study seeks to evaluate near-term outcomes of an image-guided, minimally invasive combination of chemical sclerotherapy and synthetic grafting as a novel outpatient management treatment option for UBCs. MATERIALS AND METHODS: Retrospective evaluation from August 2018 to July 2020 of fourteen pediatric patients, ages 5-14 years, undergoing treatment for a UBC, at a single institution. All UBCs were treated in a single, minimally invasive, image-guided procedure using percutaneous needle access into the UBC followed by chemical sclerotherapy and injection of regenerative synthetic graft. Patients were followed clinically and with serial radiographs to evaluate for healing and complications, with an average follow-up of 13.7 months. Descriptive statistics were performed. RESULTS: Twelve of 14 (85.7%) patients showed Modified Neer classification class 1 or 2 healed cysts at their most recent follow-up. There were two recurrences. All patients were pain-free and returned to normal physical activity on average within 2.0 months, and all patients with healed cysts remained asymptomatic at the most recent follow-up. There were no complications related to the procedures. CONCLUSIONS: Image-guided chemical sclerosis and bone grafting is a minimally invasive treatment option for unicameral bone cysts and compares favorably to other existing treatment options. The preliminary findings of this technique are promising as an alternative management option for UBCs.

Pediatric Sports Injuries.

Pediatric sports injuries are becoming more prevalent as children participate in sports. This has resulted in more imaging of pediatric injuries. The growing skeleton has features that result in unique injury patterns and radiologic findings. The article discusses the special features of bones including the growth plate, apophyses, cortex, and periosteum. Pediatric-specific sports injuries and conditions in the most common joints are then reviewed including the elbow, hip, and knee. The imaging appearances of these entities will be described with a multimodality approach including radiographs, CT, ultrasound, and MRI. The most important radiologic findings to identify will be highlighted throughout the article.

MR neurography of the brachial plexus in adult and pediatric age groups: evolution, recent advances, and future directions.

Introduction: MR neurography (MRN) of the brachial plexus has emerged in recent years as a safe and accurate modality for the identification of brachial plexopathies in pediatric and adult populations. While clinical differentiation of brachial plexopathy from cervical spine-related radiculopathy or nerve injury has long relied upon nonspecific physical exam and electrodiagnostic testing modalities, MRN now permits detailed interrogation of peripheral nerve anatomy and pathology, as well as assessment of surrounding soft tissues and musculature, thereby facilitating accurate diagnosis. The reader will learn about the current state of brachial plexus MRN, including recent advances and future directions, and gain knowledge about the adult and pediatric brachial plexopathies that can be characterized using these techniques.Areas Covered: The review details recent developments in brachial plexus MRN, including increasing availability of 3.0-T MR scanners at both private and academic diagnostic imaging centers, as well as the advent of multiple new vascular and fat signal suppression techniques. A literature search of PubMed and SCOPUS was used as the principal source of information gathered for this review.Expert Opinion: Refinement of fat-suppression, 3D techniques and diffusion MR imaging modalities has improved the accuracy of MRN, rendering it as a useful adjunct to clinical findings during the evaluation of suspected brachial plexus lesions.

Melorheostosis mimicking synovial osteochondromatosis.

Melorheostosis is an uncommon, sporadic, sclerosing bone lesion that may affect the adjacent soft tissues. It has been associated with many entities such as osteopoikilosis, soft tissue vascular malformations, bone and soft tissue tumors, nephrotic syndrome, segmental limb contractures, osteosarcoma, desmoid tumor, and mesenteric fibromatosis. Synovial osteochondromatosis is a benign neoplasia of the hyaline cartilage presenting as nodules in the subsynovial tissue of a joint or tendon sheath. The intra-articular extension of melorheostosis mimicking synovial osteochondromatosis has not been reported before. In this article, the authors describe an unusual case mimicking synovial chondromatosis arising as a result of melorheostosis and their characteristic imaging findings.

Diverticulitis complicated by fistulous communication of sigmoid colon with anterior sacral meningocele in a patient with Marfan syndrome.

Rare in the general public, dural ectasia is a common finding in patients with Marfan syndrome. Complications are not frequent but include constipation, urinary retention, and meningitis. Presented here is a case of bacterial meningitis secondary to fistulous communication between a sacral meningocele and sigmoid colon in the setting of diverticulitis.

Dehiscence of coronary artery graft presenting as a right breast mass.

Coronary artery anastomotic dehiscence is a rare complication following aortic root repair in Marfan's disease. In this patient who presented several years after surgery with mediastinal and chest wall hematoma, gated IV contrast enhanced cardiac CT was able to noninvasively localize left main coronary artery anastomotic dehiscence as the source of bleeding.

Colonic endometriosis mimicking colon cancer on a virtual colonoscopy study: a potential pitfall in diagnosis.

Colonic endometriosis has been reported in the literature to mimic colon cancer. Patients can present with symptoms almost identical to colon cancer. We present an exemplary case of a woman who was found to have a mass on conventional colonoscopy. Virtual colonoscopy was instrumental in characterizing the obstructive sigmoid mass. A biopsy of the mass revealed sigmoid endometriosis.