Mechanical properties of pediatric low-grade gliomas in children with and without neurofibromatosis type 1.

INTRODUCTION: Prognoses for pediatric brain tumors are suboptimal, as even in low-grade tumors, management techniques can lead to damage in the developing brain. Therefore, advanced neuroimaging methods are critical for developing optimal management plans and improving patient care. Magnetic resonance elastography (MRE) has allowed for the characterization of adult gliomas by their mechanical properties, which are uniquely sensitive to the complex interplay of cellularity, vasculature, and interstitium. However, pediatric tumors differ in behavior and cytoarchitecture, and their mechanical properties have never been assessed. METHODS: Here, we conduct the first study of pediatric brain tumor mechanical properties by using MRE to measure tissue stiffness and damping ratio in low grade gliomas (LGGs). We additionally measure the mechanical properties of non-neoplastic focal abnormal signal intensities (FASIs) in children with neurofibromatosis type 1 (NF1). RESULTS: 23 patients age 4-17 years who had MR imaging results consistent with a primary LGG or with NF1 were included in this study. We found that pediatric gliomas are on an average 10.9% softer (p = 0.010) with a 17.3% lower (p = 0.009) viscosity than reference tissue. Softness of tumors appeared consistent across tumor subtypes and unrelated to tumor size or contrast-enhancement. In NF1 we found that, unlike gliomas, FASIs are stiffer, though not significantly, than reference tissue by an average of 10.4% and have a 16.7% lower damping ratio. CONCLUSIONS: Measuring tumor mechanical properties patterning and heterogeneity has potential to aid in prediction of biological behavior and inform management strategies for pediatric patients.

Radiotracers for Molecular Imaging of Angiotensin-Converting Enzyme 2.

Angiotensin-converting enzymes (ACE) are well-known for their roles in both blood pressure regulation via the renin-angiotensin system as well as functions in fertility, immunity, hematopoiesis, and many others. The two main isoforms of ACE include ACE and ACE-2 (ACE2). Both isoforms have similar structures and mediate numerous effects on the cardiovascular system. Most remarkably, ACE2 serves as an entry receptor for SARS-CoV-2. Understanding the interaction between the virus and ACE2 is vital to combating the disease and preventing a similar pandemic in the future. Noninvasive imaging techniques such as positron emission tomography and single photon emission computed tomography could noninvasively and quantitatively assess in vivo ACE2 expression levels. ACE2-targeted imaging can be used as a valuable tool to better understand the mechanism of the infection process and the potential roles of ACE2 in homeostasis and related diseases. Together, this information can aid in the identification of potential therapeutic drugs for infectious diseases, cancer, and many ACE2-related diseases. The present review summarized the state-of-the-art radiotracers for ACE2 imaging, including their chemical design, pharmacological properties, radiochemistry, as well as preclinical and human molecular imaging findings. We also discussed the advantages and limitations of the currently developed ACE2-specific radiotracers.

PET Imaging of Neurofibromatosis Type 1 with a Fluorine-18 Labeled Tryptophan Radiotracer.

Neurofibromatosis type 1 (NF1) is a neurocutaneous disorder. Plexiform neurofibromas (PNFs) are benign tumors commonly formed in patients with NF1. PNFs have a high incidence of developing into malignant peripheral nerve sheath tumors (MPNSTs) with a 5-year survival rate of only 30%. Therefore, the accurate diagnosis and differentiation of MPNSTs from benign PNFs are critical to patient management. We studied a fluorine-18 labeled tryptophan positron emission tomography (PET) radiotracer, 1-(2-[18F]fluoroethyl)-L-tryptophan (L-[18F]FETrp), to detect NF1-associated tumors in an animal model. An ex vivo biodistribution study of L-[18F]FETrp showed a similar tracer distribution and kinetics between the wild-type and triple mutant mice with the highest uptake in the pancreas. Bone uptake was stable. Brain uptake was low during the 90-min uptake period. Static PET imaging at 60 min post-injection showed L-[18F]FETrp had a comparable tumor uptake with [18F]fluorodeoxyglucose (FDG). However, L-[18F]FETrp showed a significantly higher tumor-to-brain ratio than FDG (n = 4, p < 0.05). Sixty-minute-long dynamic PET scans using the two radiotracers showed similar kidney, liver, and lung kinetics. A dysregulated tryptophan metabolism in NF1 mice was further confirmed using immunohistostaining. L-[18F]FETrp is warranted to further investigate differentiating malignant NF1 tumors from benign PNFs. The study may reveal the tryptophan-kynurenine pathway as a therapeutic target for treating NF1.

Tracheal Narrowing and Its Impact on Anesthesia Care in Patients With Morquio A (Mucopolysaccharidosis Type IVA): An Observational Study.

BACKGROUND: Recently, tracheal narrowing has been recognized as a significant comorbid condition in patients with Morquio A, also known as mucopolysaccharidosis IVA. We studied a large cohort of patients with Morquio A to describe the extent of their tracheal narrowing and its relationship to airway management during anesthesia care. METHODS: This is an observational study, collecting data retrospectively, of a cohort of patients with Morquio A. Ninety-two patients with Morquio A syndrome were enrolled, among whom 44 patients had their airway evaluated by computed tomography angiography and had undergone an anesthetic within a year of the evaluation. Our hypothesis was that the tracheal narrowing as evaluated by computed tomography angiography increases with age in patients with Morquio A. The primary aim of the study was to examine the degree of tracheal narrowing in patients with Morquio A and describe the difficulties encountered during airway management, thus increasing awareness of both the tracheal narrowing and airway management difficulties in this patient population. In addition, the degree of tracheal narrowing was evaluated for its association with age or spirometry parameters using Spearman's rank correlation. Analysis of variance followed by the Bonferroni test was used to further examine the age-based differences in tracheal narrowing for the 3 age groups: 1 to 10 years, 11 to 20 years, and >21 years. RESULTS: Patient age showed a positive correlation with tracheal narrowing ( rs= 0.415; 95% confidence interval [95% CI], 0.138-0.691; P = .005) with older patients having greater narrowing of the trachea. Among spirometry parameters, FEF25%-75% showed an inverse correlation with tracheal narrowing as follows: FEF25%-75% versus tracheal narrowing: ( rs = -0.467; 95% CI, -0.877 to -0.057; P = .007). During anesthetic care, significant airway management difficulties were encountered, including cancelation of surgical procedures, awake intubation using flexible bronchoscope, and failed video laryngoscopy attempts. CONCLUSIONS: Clinically significant tracheal narrowing was present in patients with Morquio A, and the degree of such narrowing likely contributed to the difficulty with airway management during their anesthetic care. Tracheal narrowing worsens with age, but the progression appears to slow down after 20 years of age. In addition to tracheal narrowing, spirometry values of FEF25%-75% may be helpful in the overall evaluation of the airway in patients with Morquio A.

Clinical application of magnetic resonance elastography in pediatric neurological disorders.

Magnetic resonance elastography is a relatively new, rapidly evolving quantitative magnetic resonance imaging technique which can be used for mapping the viscoelastic mechanical properties of soft tissues. MR elastography measurements are akin to manual palpation but with the advantages of both being quantitative and being useful for regions which are not available for palpation, such as the human brain. MR elastography is noninvasive, well tolerated, and complements standard radiological and histopathological studies by providing in vivo measurements that reflect tissue microstructural integrity. While brain MR elastography studies in adults are becoming frequent, published studies on the utility of MR elastography in children are sparse. In this review, we have summarized the major scientific principles and recent clinical applications of brain MR elastography in diagnostic neuroscience and discuss avenues for impact in assessing the pediatric brain.

Abusive Head Trauma Animal Models: Focus on Biomarkers.

Abusive head trauma (AHT) is a serious traumatic brain injury and the leading cause of death in children younger than 2 years. The development of experimental animal models to simulate clinical AHT cases is challenging. Several animal models have been designed to mimic the pathophysiological and behavioral changes in pediatric AHT, ranging from lissencephalic rodents to gyrencephalic piglets, lambs, and non-human primates. These models can provide helpful information for AHT, but many studies utilizing them lack consistent and rigorous characterization of brain changes and have low reproducibility of the inflicted trauma. Clinical translatability of animal models is also limited due to significant structural differences between developing infant human brains and the brains of animals, and an insufficient ability to mimic the effects of long-term degenerative diseases and to model how secondary injuries impact the development of the brain in children. Nevertheless, animal models can provide clues on biochemical effectors that mediate secondary brain injury after AHT including neuroinflammation, excitotoxicity, reactive oxygen toxicity, axonal damage, and neuronal death. They also allow for investigation of the interdependency of injured neurons and analysis of the cell types involved in neuronal degeneration and malfunction. This review first focuses on the clinical challenges in diagnosing AHT and describes various biomarkers in clinical AHT cases. Then typical preclinical biomarkers such as microglia and astrocytes, reactive oxygen species, and activated N-methyl-D-aspartate receptors in AHT are described, and the value and limitations of animal models in preclinical drug discovery for AHT are discussed.

Ultrasonography of the pediatric elbow.

Ultrasound of the elbow can be incorporated into routine pediatric practice in the radiology department, emergency department, orthopedic clinic, and interventional suite. Ultrasound is complementary to radiography and magnetic resonance imaging for the evaluation of elbow pain in athletes with overhead activities or valgus stress, focusing on the ulnar collateral ligament medially and capitellum laterally. As a primary imaging modality, ultrasound can be used for a variety of indications including inflammatory arthritis, fracture diagnosis, and ulnar neuritis/subluxation. Ultrasound is also well-suited to guide diagnostic and therapeutic elbow joint interventions with precise localization of anatomic landmarks and needle placement. Here, we describe technical aspects of elbow ultrasound and illustrate its application in pediatric patients from infants to teen athletes.

Advanced Neuroimaging Approaches to Pediatric Brain Tumors.

Central nervous system tumors are the most common pediatric solid tumors; they are also the most lethal. Unlike adults, childhood brain tumors are mostly primary in origin and differ in type, location and molecular signature. Tumor characteristics (incidence, location, and type) vary with age. Children present with a variety of symptoms, making early accurate diagnosis challenging. Neuroimaging is key in the initial diagnosis and monitoring of pediatric brain tumors. Conventional anatomic imaging approaches (computed tomography (CT) and magnetic resonance imaging (MRI)) are useful for tumor detection but have limited utility differentiating tumor types and grades. Advanced MRI techniques (diffusion-weighed imaging, diffusion tensor imaging, functional MRI, arterial spin labeling perfusion imaging, MR spectroscopy, and MR elastography) provide additional and improved structural and functional information. Combined with positron emission tomography (PET) and single-photon emission CT (SPECT), advanced techniques provide functional information on tumor metabolism and physiology through the use of radiotracer probes. Radiomics and radiogenomics offer promising insight into the prediction of tumor subtype, post-treatment response to treatment, and prognostication. In this paper, a brief review of pediatric brain cancers, by type, is provided with a comprehensive description of advanced imaging techniques including clinical applications that are currently utilized for the assessment and evaluation of pediatric brain tumors.

Pearls and Pitfalls in Arterial Spin Labeling Perfusion-Weighted Imaging in Clinical Pediatric Imaging.

Characteristic arterial spin labeling (ASL) perfusion patterns are seen in a wide variety of pediatric brain pathologies, highlighting the potential added value and prognostic role of this magnetic resonance imaging (MRI) perfusion-weighted imaging modality. Our objective is to review the basic clinical physics, technical underpinnings, and artifacts and challenges as we highlight some of the most clinically relevant pathologies to the application of ASL in the pediatric setting.

Radiosynthesis of 1-(2-[18F]Fluoroethyl)-L-Tryptophan using a One-pot, Two-step Protocol.

The kynurenine pathway (KP) is a primary route for tryptophan metabolism. Evidence strongly suggests that metabolites of the KP play a vital role in tumor proliferation, epilepsy, neurodegenerative diseases, and psychiatric illnesses due to their immune-modulatory, neuro-modulatory, and neurotoxic effects. The most extensively used positron emission tomography (PET) agent for mapping tryptophan metabolism, α-[11C]methyl-L-tryptophan ([11C]AMT), has a short half-life of 20 min with laborious radiosynthesis procedures. An onsite cyclotron is required to radiosynthesize [11C]AMT. Only a limited number of centers produce [11C]AMT for preclinical studies and clinical investigations. Hence, the development of an alternative imaging agent that has a longer half-life, favorable in vivo kinetics, and is easy to automate is urgently needed. The utility and value of 1-(2-[18F]fluoroethyl)-L-tryptophan, a fluorine-18-labeled tryptophan analog, has been reported in preclinical applications in cell line-derived xenografts, patient-derived xenografts, and transgenic tumor models. This paper presents a protocol for the radiosynthesis of 1-(2-[18F]fluoroethyl)-L-tryptophan using a one-pot, two-step strategy. Using this protocol, the radiotracer can be produced in a 20 ± 5% (decay corrected at the end of synthesis, n > 20) radiochemical yield, with both radiochemical purity and enantiomeric excess of over 95%. The protocol features a small precursor amount with no more than 0.5 mL of reaction solvent in each step, low loading of potentially toxic 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane (K222), and an environmentally benign and injectable mobile phase for purification. The protocol can be easily configured to produce 1-(2-[18F]fluoroethyl)-L-tryptophan for clinical investigation in a commercially available module.

Assessing the Reliability of the OMERACT Juvenile Idiopathic Arthritis Magnetic Resonance Scoring System for Temporomandibular Joints (JAMRIS-TMJ).

Contrast-enhanced magnetic resonance imaging (MRI) remains the most comprehensive modality to assess juvenile idiopathic arthritis (JIA)-related inflammation and osteochondral damage in the temporomandibular joints (TMJ). This study tested the reliability of a new JIA MRI scoring system for TMJ (JAMRIS-TMJ) and the impact of variations in calibration and reader specialty. Thirty-one MRI exams of bilateral TMJs were scored independently using the JAMRIS-TMJ by 20 readers consisting of radiologists and non-radiologist clinicians in three reading groups, with or without a calibrating atlas and/or tutorial. The inter-reader reliability in the multidisciplinary cohort assessed by the generalizability coefficient was 0.61-0.67 for the inflammatory and 0.66-0.74 for the damage domain. The atlas and tutorial did not improve agreement within radiologists, but improved the agreement between radiologist and non-radiologist groups. Agreements between different calibration levels were 0.02 to 0.08 lower by the generalizability coefficient compared to agreement within calibration levels; agreement between specialty groups was 0.04 to 0.10 lower than within specialty groups. Averaging two radiologists raised the reliability above 0.8 for both domains. Therefore, the reliability of JAMRIS-TMJ was moderate-to-good depending on the presence of specialty and calibration differences. The atlas and tutorial are necessary to improve reliability when the reader cohort consists of multiple specialties.

Unravelling neuroinflammation in abusive head trauma with radiotracer imaging.

Abusive head trauma (AHT) is a leading cause of mortality and morbidity in child abuse, with a mortality rate of approximately 25%. In survivors, the prognosis remains dismal, with high prevalence of cerebral palsy, epilepsy and neuropsychiatric disorders. Early and accurate diagnosis of AHT is challenging, both clinically and radiologically, with up to one-third of cases missed on initial examination. Moreover, most of the management in AHT is supportive, reflective of the lack of clear understanding of specific pathogenic mechanisms underlying secondary insult, with approaches targeted toward decreasing intracranial hypertension and reducing cerebral metabolism, cell death and excitotoxicity. Multiple studies have elucidated the role of pro- and anti-inflammatory cytokines and chemokines with upregulation/recruitment of microglia/macrophages, oligodendrocytes and astrocytes in severe traumatic brain injury (TBI). In addition, recent studies in animal models of AHT have demonstrated significant upregulation of microglia, with a potential role of inflammatory cascade contributing to secondary insult. Despite the histological and biochemical evidence, there is a significant dearth of specific imaging approaches to identify this neuroinflammation in AHT. The primary motivation for development of such imaging approaches stems from the need to therapeutically target neuroinflammation and establish its utility in monitoring and prognostication. In the present paper, we discuss the available data suggesting the potential role of neuroinflammation in AHT and role of radiotracer imaging in aiding diagnosis and patient management.

Birth-related subdural hemorrhage: prevalence and imaging morphology.

BACKGROUND: Birth trauma accounts for 1-2% of the mortality in newborns with significant intracranial injuries presenting in the immediate postnatal period. However, a significant number of asymptomatic neonates harbor birth-related intracranial hemorrhage (ICH), with birth-related subdural hemorrhage (SDH) being a common occurrence on infant brain CT and MRI studies performed as a standard of care for a variety of reasons. Although clinically insignificant, birth-related SDH is frequently brought up in courts as an alternative explanation for SDH in suspected abusive head trauma. OBJECTIVE: The aim of this study was to determine prevalence, imaging morphology and distribution of birth-related SDHs on brain CT and MRI studies obtained as a standard of care in infants up to 1 month old. We further tried to ascertain the relationship of birth-related SDHs with mode of delivery and birth weight. MATERIALS AND METHODS: Infants up to the age of 1 month who had CT or MRI of the brain performed between Jan. 1, 2018, and March 29, 2020, were included in this retrospective observational study. In addition to the imaging data, we reviewed clinical history, birth history including birth weight and mode of delivery, and final diagnoses. RESULTS: Two hundred six infants younger than 30 days (range 0-29 days, mean 11.9 days, median 11 days and standard deviation [SD] 8.4 days) had a CT or MRI study during the study period. Among these, 58 infants were excluded as per the exclusion criteria. Among the included 148 infants, 88 (59.5%) had no imaging evidence of SDH. An additional 56 (37.8%) infants were assessed as having birth-related SDH based on review of clinical data. Within the birth-related SDH cohort (56 infants), only supratentorial SDH was identified in 5 (8.9%), only infratentorial SDH was identified in 14 (25%), while SDHs within both compartments were identified in 37 (66.1%) infants. The most common location for supratentorial birth-related SDH was along the occipital lobes (31/42, 73.8%), with other common locations being along the posterior interhemispheric fissure (30/42, 71.4%) and fronto-parietal convexity (9/42, 21.4%). The distribution of posterior fossa SDH was along the tentorium (38/51, 74.5%), along the cerebellum (38/51, 74.5%) and in both the locations (25/51, 49.0%). The rate of SDH was significantly higher in vaginal delivery group (46/84, 54.7%) as compared to caesarean section group (10/57, 17.5%) (P<0.05). We did not find any statistically significant difference between the birth weights of normal and birth-related SDH cohorts (P>0.05). CONCLUSION: Birth-related SDH is a common occurrence, with our study suggesting a prevalence of 37.8%. The most common distribution of birth-related SDH is within both the supra- and infratentorial compartments (66.1%) followed by infratentorial compartment (25%). The rate of birth-related SDH was significantly higher in vaginal delivery group as compared to caesarean section group.

Tracheal narrowing in children and adults with mucopolysaccharidosis type IVA: evaluation with computed tomography angiography.

BACKGROUND: Mucopolysaccharidosis type IVA (MPS IVA) is characterized by progressive skeletal dysplasia and respiratory issues with difficult airway management during anesthesia. OBJECTIVE: To characterize tracheal abnormalities in children and adults with MPS IVA including interplay of the trachea, vasculature, bones and thyroid at the thoracic inlet. MATERIALS AND METHODS: Computed tomography (CT) angiograms of the chest were analyzed for trachea shape, narrowing and deviation at the thoracic inlet, course of vasculature, bone alignment and thyroid location. The tracheal cross-sectional area was measured at the cervical, thoracic inlet and intrathoracic levels. RESULTS: Thirty-seven patients (mean age: 18.1 years) were included. The mean tracheal cross-sectional area narrowing at the thoracic inlet was 63.9% (range: -2.1-96%), with a trend for increased tracheal narrowing in older children. The trachea was commonly deviated rightward posterior (22/37, 59%). T- or W-shaped tracheas had two times greater tracheal narrowing than D- or U-shaped tracheas (P<0.05). The brachiocephalic artery was tortuous in 35/37 (95%) with direct impingement on the trachea in 24/37 (65%). No correlation was observed between bony thoracic inlet diameter and tracheal narrowing. The thyroid was located in the thoracic inlet in 28/37 (76%) cases, significantly associated with tracheal narrowing (P=0.016). CONCLUSION: Narrowing, deviation and abnormal shape of the trachea at the thoracic inlet are common in children and adults with MPS IVA, with a trend toward increased narrowing with advancing age in children. A W- or T-shaped trachea is associated with focal tracheal narrowing. Crowding of the thoracic inlet, due to vascular tortuosity and thyroid position, appears to play a major role.

Successful use of transarterial radioembolization with yttrium-90 (TARE-Y90) in two children with hepatoblastoma.

Primary malignant liver tumors are rare but all require surgical resection as part of therapy with curative intent. A minority of patients have resectable tumors at diagnosis. Chemotherapy has a therapeutic role in hepatoblastoma but only one-third of patients have resectable disease at diagnosis. Two children with hepatoblastoma and suboptimal responses to initial chemotherapy received therapy with transarterial radioembolization utilizing yttrium-90 (TARE-Y90) and had significant response leading to resection and remission. The role of TARE-Y90 needs to be studied further to define its use in primary pediatric liver neoplasms.

Natural history of Morquio A patient with tracheal obstruction from birth to death.

Morquio A syndrome (mucopolysaccharidosis IVA, MPS IVA) is a lysosomal storage disease caused by a deficiency of N-acetylgalactosamine-6-sulfate sulfatase, resulting in systemic accumulation of the partially degraded glycosaminoglycans (GAGs), keratan sulfate and chondroitin-6-sulfate. The accumulation of these GAGs leads to distinguishing features as skeletal dysplasia with disproportionate dwarfism, short neck, kyphoscoliosis, pectus carinatum, tracheal obstruction, coxa valga, genu valgum, and joint laxity. In the absence of autopsied cases and systemic analysis of multiple tissues, the pathological mechanism of the characteristic skeletal dysplasia associated with the disease largely remains a question. Here we report an autopsied case of a 23-year-old male with MPS IVA, who developed characteristic skeletal abnormalities by 4 months of age and died of severe tracheal obstruction and hypoventilation originating from respiratory muscle weakness from neurological cord deficit due to cord myelopathy at the age of 23. We analyzed postmortem tissues pathohistologically, including the thyroid, lung, lung bronchus, trachea, heart, aorta, liver, spleen, kidney, testes, humerus, knee cartilage, and knee ligament. Examination of the tissues demonstrated systemic storage materials in multiple tissues, as well as severely ballooned and vacuolated chondrocytes in the trachea, humerus, knee cartilage, and lung bronchus. This autopsied case with MPS IVA addresses the importance of tracheal obstruction for morbidity and mortality of the disease, and the pathological findings contribute to a further understanding of the pathogenesis of MPS IVA and the development of novel therapies.

Chronic lesser tuberosity avulsion in an adolescent with an associated biceps pulley injury.

We report a case of a 15-year-old boy with chronic intermittent left shoulder pain due to an undiagnosed lesser tuberosity avulsion fracture, an associated biceps pulley injury and intra-articular dislocation of the long head of the biceps tendon. Lesser tuberosity avulsion fractures are rare injuries that are difficult to detect on clinical exam and radiographically, which may lead to delayed diagnosis and chronic shoulder instability. Few reports describe dislocations or subluxations of the biceps tendon in association with lesser tuberosity avulsions in children. We utilize this case to emphasize the importance of MR not only in detecting lesser tuberosity avulsions, but also in evaluating biceps pulley injuries, which are a rarely reported, but clinically important, association.

Musculoskeletal MRI findings of juvenile localized scleroderma.

BACKGROUND: Juvenile localized scleroderma comprises a group of autoimmune conditions often characterized clinically by an area of skin hardening. In addition to superficial changes in the skin and subcutaneous tissues, juvenile localized scleroderma may involve the deep soft tissues, bones and joints, possibly resulting in functional impairment and pain in addition to cosmetic changes. OBJECTIVE: There is literature documenting the spectrum of findings for deep involvement of localized scleroderma (fascia, muscles, tendons, bones and joints) in adults, but there is limited literature for the condition in children. We aimed to document the spectrum of musculoskeletal magnetic resonance imaging (MRI) findings of both superficial and deep juvenile localized scleroderma involvement in children and to evaluate the utility of various MRI sequences for detecting those findings. MATERIALS AND METHODS: Two radiologists retrospectively evaluated 20 MRI studies of the extremities in 14 children with juvenile localized scleroderma. Each imaging sequence was also given a subjective score of 0 (not useful), 1 (somewhat useful) or 2 (most useful for detecting the findings). RESULTS: Deep tissue involvement was detected in 65% of the imaged extremities. Fascial thickening and enhancement were seen in 50% of imaged extremities. Axial T1, axial T1 fat-suppressed (FS) contrast-enhanced and axial fluid-sensitive sequences were rated most useful. CONCLUSION: Fascial thickening and enhancement were the most commonly encountered deep tissue findings in extremity MRIs of children with juvenile localized scleroderma. Because abnormalities of the skin, subcutaneous tissues and fascia tend to run longitudinally in an affected limb, axial T1, axial fluid-sensitive and axial T1-FS contrast-enhanced sequences should be included in the imaging protocol.

Surgical Reconstruction for Severe Tracheal Obstruction in Morquio A Syndrome.

Progressive tracheal obstruction is commonly seen in Morquio A syndrome and can lead to life-threatening complications. Although tracheostomy can address severe upper airway obstruction, lower airway obstruction, commonly associated with a narrow thoracic inlet and vascular compression, requires an alternative approach. We describe the case of a 16-year-old patient with Morquio A syndrome whose near-fatal tracheal obstruction was relieved by timely surgical tracheal vascular reconstruction with dramatic resolution of his respiratory symptoms.