Achint K. Singh

Imaging of neurosarcoidosis: common, uncommon, and rare.

Sarcoidosis is an idiopathic inflammatory disease that may affect any organ system and have protean manifestations. Neurosarcoidosis refers to involvement of the central nervous system and may occur in patients with known sarcoidosis, or be the initial manifestation of the disease. In the latter, it can be a source of considerable confusion, given the non-specific imaging appearance. The aim of this review is to describe the imaging spectrum of neurosarcoidosis, including follow-up imaging and superimposed infections, which may occur secondary to immunosuppression. An increased awareness of this great mimicker could potentially expedite diagnosis and reduce morbidity.

Case 164: Funicular Type of Spermatic Cord Hydrocele

Differentiation of funicular hydrocele from simple scrotal hydrocele with US is essential, as the management of these entities is different.

Demystifying orbital emergencies: A pictorial review

Imaging of the orbit plays an important role in the workup of orbital emergencies. Orbital imaging is particularly useful in the emergency department, where clinical history and physical examination may be limited or delayed until the exclusion or treatment of more life-threatening conditions. Cross-sectional orbital imaging with multidetector computed tomography (CT) and magnetic resonance (MR) imaging is commonly performed in addition to ultrasonography. In an emergent setting, CT is the preferred modality when evaluating for intraorbital foreign bodies, fractures, or calcifications within a mass lesion. MR imaging is typically the modality of choice for orbital pathologic conditions, owing to its superior ability to delineate the orbital soft tissues and visual pathways. CT and MR imaging together may supplement clinical evaluation by helping establish an accurate diagnosis, providing an objective assessment of disease extent and progression, and assisting in pretreatment planning. Orbital emergencies have a spectrum of cross-sectional imaging findings in four major categories: infection, trauma, vascular disease, and inflammation. Use of a systematic approach to these entities will assist the radiologist with identifying immediate threats to vision and thereby facilitate prompt clinical management. Familiarity with the clinical presentations also improves the radiologists diagnostic confidence and role in guiding patient care. This article reviews imaging protocols, relevant orbital anatomy, the role of CT and MR imaging, and key imaging findings of orbital emergencies that the radiologist must know.

Basion–Cartilaginous Dens Interval: An Imaging Parameter for Craniovertebral Junction Assessment in Children

BACKGROUND AND PURPOSE: Widening of the basion-dens interval is an important sign of cranioverterbral junction injury. The current literature on basion-dens interval in children is sparse and based on bony measurements with variable values. Our goal was to establish the normal values of a recently described new imaging parameter, the basion–cartilaginous dens interval in children. MATERIALS AND METHODS: Three hundred healthy pediatric patients (0–10 years of age) were selected retrospectively. These patients were divided into 3 different groups: A (0–3 years), B (3–6 years), and C (6–10 years). The basion–cartilaginous dens interval was calculated on the sagittal MPR image of cervical spine CT in a soft-tissue window. The mean, SD, and the upper limit of normal (mean +2 SDs) of the 3 groups were calculated, and statistical tests were used to check for significant differences of the basion–cartilaginous dens interval among these 3 groups. RESULTS: The upper limits of the basion–cartilaginous dens interval for the 3 groups were 5.34 mm in group A, 5.64 mm in group B, and 7.24 mm in group C. There were statistically significant differences in the basion–cartilaginous dens interval values among the 3 groups. There was no statistically significant difference in basion–cartilaginous dens interval values between groups A and B; however, values in group C were significantly different from those in both A and B. There was no statistically significant difference in the basion–cartilaginous dens interval values between males and females. CONCLUSIONS: The basion–cartilaginous dens interval is a novel imaging parameter to assess cranioverterbral junction integrity in children, which includes the nonossified cartilage in the measurement.

Stroke-like migraine attacks after radiation therapy syndrome: Case report and review of the literature:

A 26-year-old female presented with vision loss accompanied by migraine-like headaches. A contrast-enhanced magnetic resonance imaging of the brain was performed which revealed findings suggestive of stroke-like migraine attacks after radiation therapy (SMART) syndrome. SMART syndrome is a delayed complication of brain radiation characterized by neurologic symptoms including migraine-like headaches, seizures, and hemispheric impairment. The purpose of this article is to make the readers aware of this rare complication of brain irradiation. Appropriate diagnosis of SMART syndrome is essential to avoid invasive tests.

Imaging of Skeletal Disorders Caused by Fibroblast Growth Factor Receptor Gene Mutations

Fibroblast growth factors and fibroblast growth factor receptors (FGFRs) play important roles in human axial and craniofacial skeletal development. FGFR1, FGFR2, and FGFR3 are crucial for both chondrogenesis and osteogenesis. Mutations in the genes encoding FGFRs, types 1-3, are responsible for various skeletal dysplasias and craniosynostosis syndromes. Many of these disorders are relatively common in the pediatric population, and diagnosis is often challenging. These skeletal disorders can be classified based on which FGFR is affected. Skeletal disorders caused by type 1 mutations include Pfeiffer syndrome (PS) and osteoglophonic dysplasia, and disorders caused by type 2 mutations include Crouzon syndrome (CS), Apert syndrome (AS), and PS. Disorders caused by type 3 mutations include achondroplasia, hypochondroplasia, thanatophoric dysplasia (TD), severe achondroplasia with developmental delay and acanthosis nigricans, Crouzonodermoskeletal syndrome, and Muenke syndrome. Most of these mutations are inherited in an autosomal dominant fashion and are gain-of-function-type mutations. Imaging plays a key role in the evaluation of these skeletal disorders. Knowledge of the characteristic imaging and clinical findings can help confirm the correct diagnosis and guide the appropriate molecular genetic tests. Some characteristics and clinical findings include premature fusion of cranial sutures and deviated broad thumbs and toes in PS; premature fusion of cranial sutures and syndactyly of the hands and feet in AS; craniosynostosis, ocular proptosis, and absence of hand and foot abnormalities in CS; rhizomelic limb shortening, caudal narrowing of the lumbar interpediculate distance, small and square iliac wings, and trident hands in achondroplasia; and micromelia, bowing of the femora, and platyspondyly in TD. ©RSNA, 2017.

Posterior fossa syndrome with delayed MR evidence of unilateral superior cerebellar peduncle (SCP) damage

Posterior fossa syndrome (PFS) is a well-known sequela of midline posterior fossa tumor resection. Patients typically exhibit transient behavioral, motor, and oculomotor disturbances that resolve within a few weeks to several months after surgery. The underlying pathophysiology of PFS is not completely understood, but contemporary literature has implicated injury to the dentate nucleus and/or exiting dentatothalamocortical fiber bundles as a causative factor. The authors present a case of a young male who developed a delayed variant of PFS typified by motor deficits and demonstrated diffusion restriction in the ipsilateral superior cerebellar peduncle. Because the correlation between PFS and the superior cerebellar peduncle injury is poorly described in the literature, particularly with regard to relevant radiographic imaging, the authors of this report hope their findings will contribute to that insufficient body of evidence.

Pediatric Mediastinal Tumors and Tumor-Like Lesions

This article reviews the imaging findings of pediatric mediastinal tumors and tumor-like lesions. The classification of the mediastinum is discussed with normal imaging appearance of the thymus in pediatric age group followed by a discussion on multiple mediastinal lesions in different compartments with emphasis on their imaging characteristics.

Imaging Spectrum of Facial Nerve Lesions

The facial nerve is affected by a wide variety of pathologies, including congenital, traumatic, inflammatory, and neoplastic conditions. Imaging plays a vital role in the diagnosis of these pathologies. The facial nerve has a complex anatomy and course. A strong grasp of normal facial nerve anatomy is essential for the radiologist to maintain a high level of diagnostic sensitivity. This article details the normal imaging anatomy of the facial nerve and the imaging features of common facial nerve pathologies.