Genes Implicated in Rare Congenital Inner Ear and Cochleovestibular Nerve Malformations.

OBJECTIVE: A small subset of children with congenital hearing loss have abnormal cochleovestibular nerves (i.e., absent, aplastic, or deficient cochlear nerves), with largely unknown etiology. Our objective was to investigate the underlying pathways and identify novel genetic variants responsible for cochleovestibular malformations and nerve abnormalities. It is our hypothesis that several cochleovestibular nerve abnormalities might share common causative pathways. DESIGN: We used a family-based exome sequencing approach to study 12 children with known rare inner ear and/or cochleovestibular nerve malformations. RESULTS: Our results highlight a diverse molecular etiology and suggest that genes important in the developing otic vesicle and cranial neural crest, e.g., MASP1, GREB1L, SIX1, TAF1, are likely to underlie inner ear and/or cochleovestibular nerve malformations. CONCLUSIONS: We show that several cochleovestibular nerve malformations are neurocristopathies, which is consistent with the fact that cochleovestibular nerve development is based on otic placode-derived neurons in close association with neural crest-derived glia cells. In addition, we suggest potential genetic markers for more severely affected phenotypes, which may help prognosticate individual cochlear implantation outcomes. Developing better strategies for identifying which children with abnormal nerves will benefit from a cochlear implantation is crucial, as outcomes are usually far less robust and extremely variable in this population, and current neuroimaging and electrophysiologic parameters cannot accurately predict outcomes. Identification of a suitable treatment early will reduce the use of multiple interventions during the time-sensitive period for language development.

Traumatic Neck and Skull Base Injuries.

Patients with blunt and penetrating traumatic injuries to the skull base and soft tissues of the neck present to the emergency department every day. Fortunately, truly life-threatening injuries to these regions are relatively uncommon. However, when encountered and not correctly diagnosed, these entities may result in severe morbidity or mortality. The radiologist plays a critical role recognizing these injuries, in which findings may often be subtle and the anatomy potentially challenging to identify. Multisection CT and CT angiography are commonly performed to assess these injuries in the emergency department. Vascular injury to the neck may result in dissection, occlusion, pseudoaneurysm formation, or frank extravasation resulting in stroke or death. Airway compromise may result from laryngotracheal injury. Injuries to the pharynx and esophagus may result in perforation. Injuries to the temporal bone may result in vascular injury to the internal carotid artery or facial nerve injury, which would require immediate surgery or intervention to prevent paralysis.©RSNA, 2019.

Abnormal Cochleovestibular Anatomy and Hearing Outcomes: Pediatric Patients with a Questionable Cochleovestibular Nerve Status May Benefit from Cochlear Implantation and/or Hearing Aids.

OBJECTIVE: Imaging characteristics and hearing outcomes in children with cochleovestibular or cochleovestibular nerve (CVN) abnormalities. STUDY DESIGN: Retrospective, critical review. SETTING: Tertiary referral academic center. PATIENTS: Twenty-seven children with CVN abnormalities with magnetic resonance (MRI) and/or computed tomography (CT). Study Intervention(s): None. MAIN OUTCOME MEASURE(S): Determine the likely presence or absence of a CNV and auditory stimulation responses. RESULTS: Two of 27 cases had unilateral hearing loss, and all others had bilateral loss. Eleven (46%) were identified with a disability or additional condition. Twenty-two (42%) ears received a cochlear implant (CI) and 9 ears (17%) experienced no apparent benefit from the device. MRI acquisition protocols were suboptimal for identification of the nerve in 22 (42%) ears. A likely CVN absence was associated with a narrow cochlear aperture and internal auditory canal and cochlear malformation. Thirteen (48%) children with an abnormal nerve exhibited normal cochleae on the same side. Hearing data were available for 30 ears, and 25 ears (83%) exhibited hearing with or without an assistive device. One child achieved closed set speech recognition with a hearing aid, another with a CI. One child achieved open set speech recognition with a CI. CONCLUSIONS: Current imaging cannot accurately characterize the functional status of the CVN or predict an assistive device benefit. Children who would have otherwise been denied a CI exhibited auditory responses after implantation. A CI should be considered in children with abnormal CVN. Furthermore, imaging acquisition protocols need standardization for clear temporal bone imaging.

A case report of two different skull base pathologies causing hearing loss in the same ear: vestibular schwannoma and superior semicircular canal dehiscence.

Vestibular schwannoma and superior semicircular canal dehiscence are both uncommon entities, especially when present in the same ear. Here we illustrate how both of these pathologies can be repaired through the same surgical exposure, of the middle cranial fossa, with complete preservation of the cochlear nerve function and relief of symptoms caused by canal dehiscence.

Paradoxical embolism: role of imaging in diagnosis and treatment planning.

Paradoxical embolism (PDE) is an uncommon cause of acute arterial occlusion that may have catastrophic sequelae. The possibility of its presence should be considered in all patients with an arterial embolus in the absence of a cardiac or proximal arterial source. Despite advancements in radiologic imaging technology, the use of various complementary modalities is usually necessary to exclude other possibilities from the differential diagnosis and achieve an accurate imaging-based diagnosis of PDE. In current practice, the imaging workup of a patient with symptoms of PDE usually starts with computed tomography (CT) and magnetic resonance (MR) imaging to identify the cause of the symptoms and any thromboembolic complications in target organs (eg, stroke, peripheral arterial occlusion, or visceral organ ischemia). Additional imaging studies with modalities such as peripheral venous Doppler ultrasonography (US), transcranial Doppler US, echocardiography, and CT or MR imaging are required to detect peripheral and central sources of embolism, identify cardiac and/or extracardiac shunts, and determine whether arterial disease is present. To guide radiologists in selecting the optimal modalities for use in various diagnostic settings, the article provides detailed information about the imaging of PDE, with numerous radiologic and pathologic images illustrating the wide variety of features that may accompany and contribute to the pathologic process. The roles of CT and MR imaging in the diagnosis and exclusion of PDE are described, and the use of imaging for planning surgical treatment and interventional procedures is discussed.

Image coregistration: quantitative processing framework for the assessment of brain lesions.

The quantitative, multiparametric assessment of brain lesions requires coregistering different parameters derived from MRI sequences. This will be followed by analysis of the voxel values of the ROI within the sequences and calculated parametric maps, and deriving multiparametric models to classify imaging data. There is a need for an intuitive, automated quantitative processing framework that is generalized and adaptable to different clinical and research questions. As such flexible frameworks have not been previously described, we proceeded to construct a quantitative post-processing framework with commonly available software components. Matlab was chosen as the programming/integration environment, and SPM was chosen as the coregistration component. Matlab routines were created to extract and concatenate the coregistration transforms, take the coregistered MRI sequences as inputs to the process, allow specification of the ROI, and store the voxel values to the database for statistical analysis. The functionality of the framework was validated using brain tumor MRI cases. The implementation of this quantitative post-processing framework enables intuitive creation of multiple parameters for each voxel, facilitating near real-time in-depth voxel-wise analysis. Our initial empirical evaluation of the framework is an increased usage of analysis requiring post-processing and increased number of simultaneous research activities by clinicians and researchers with non-technical backgrounds. We show that common software components can be utilized to implement an intuitive real-time quantitative post-processing framework, resulting in improved scalability and increased adoption of post-processing needed to answer important diagnostic questions.

Utility of Neuroimaging in the Management of Chronic and Acute Headache.

Imaging plays an important role in identifying the cause of the much less common secondary headaches. Such headaches may be caused by a variety of pathologic conditions which can be categorized as intracranial and extracranial. Idiopathic intracranial hypertension imaging findings include "empty sella," orbital changes, and dural venous sinus narrowing. Intracranial hypotension (ICH) is frequently caused by CSF leaks. Imaging findings include loss of the CSF spaces, downward displacement of the brain, as well as dural thickening and enhancement. Severe cases of ICH may result in subdural hematomas. A variety of intracranial and skull base tumors may cause headaches due to dural involvement. Extracranial tumors and lesions that frequently present with headaches include a variety of sinonasal tumors as well as mucoceles. Neurovascular compression disorders causing headaches include trigeminal and glossopharyngeal neuralgia. Imaging findings include displacement and atrophy of the cranial nerve caused by an adjacent arterial or venous structure.

Can Imaging Predict Hearing Outcomes in Children With Cochleovestibular Nerve Abnormalities?

OBJECTIVES/HYPOTHESIS: To identify the imaging characteristics associated with better hearing outcomes found in cochleovestibular nerve (CVN) abnormalities treated with hearing aids and/or cochlear implantation (CI). STUDY DESIGN: Retrospective review. METHODS: A retrospective review was undertaken of 69 ears with CVN abnormalities seen on magnetic resonance imaging (MRI) treated at a tertiary referral academic center analyzing the clinical features, imaging characteristics, and hearing data. We searched for associations among the hearing and imaging data, hypothesizing that the imaging data was not a good indicator of hearing function. RESULTS: In univariable analysis of all those who underwent aided testing (hearing aid and CI), health status (P = .016), internal auditory canal (IAC) midpoint diameter (P < .001), and number of nerves in the IAC (P < .001) were predictors of positive hearing outcome. Modiolar abnormalities, cochlear aperture diameter, cochlear malformations, vestibular malformations, and nerves in the cerebellar cistern did not predict hearing outcome (P = .79, .18, .59, .09, .17, respectively). For patients who received CI, health status (P = .018), IAC midpoint (P = .024), and number of nerves in the IAC (P = .038) were significant. When controlling for health status, IAC midpoint diameter (P < .001) and number of nerves in the IAC (P < .001) remained significant. In our cohort, one out of the eight ears (13%) with Birman class 0 or 1 exhibited responses to sound compared to nine out of 13 ears (70%) with Birman class 2-4. CONCLUSIONS: Current imaging modalities cannot accurately depict the status of the cochleovestibular nerve or predict a child's benefit with a CI. Cochlear implantation should be considered in children with abnormal cochleovestibular nerves. LEVEL OF EVIDENCE: 3 Laryngoscope, 132:S1-S15, 2022.

Abnormal cochleovestibular anatomy and imaging: Lack of consistency across quality of images, sequences obtained, and official reports.

OBJECTIVES: There are significant variations across centers on how to acquire and interpret imaging of children with congenital sensorineural hearing loss and cochleovestibular abnormalities. This study assesses the quality of imaging, sequences included, and accuracy of official radiology reports, to determine if these children are being assessed appropriately. METHODS: This study is retrospective review of CTs and MRIs from 40 pediatric patients diagnosed with profound sensorineural hearing loss and cochleovestibular structure/nerve abnormalities presenting to a tertiary referral academic center. Images were reviewed by two experienced neuroradiologists and a neurotologist. Findings were compared to official reports, when available. RESULTS: Twelve (30%) patients had an MRI only, while 28 (70%) had both an MRI and a CT. There were 3 (10.7%) CTs and 7 (17.5%) MRIs noted to be of poor quality. Children received an average of 6.8 (±2.7) CT acquisitions and 10.9 (±5.7) MRI acquisitions. There was non-concordance between the official report and expert review for 27 (71.1%) ears on CT and 27 (56.3%) ears on MRI. CONCLUSIONS: These data demonstrate high variability in protocols and quality of medical imaging of children with sensorineural hearing loss. Interpretation of images is highly discordant between official reports and tertiary review. Given these results, we recommend that these children be imaged and evaluated at centers with neuroradiologists who are experienced in interpreting congenital abnormalities of the cochleovestibular system.

Virtual Read-Out: Radiology Education for the 21st Century During the COVID-19 Pandemic.

Technologic advances have resulted in the expansion of web-based conferencing and education. While historically video-conferencing has been used for didactic educational sessions, we present its novel use in virtual radiology read-outs in the face of the COVID-19 pandemic. Knowledge of key aspects of set-up, implementation, and possible pitfalls of video-conferencing technology in the application of virtual read-outs can help to improve the educational experience of radiology trainees and promote potential future distance learning and collaboration.

Posterior Reversible Encephalopathy Syndrome (PRES): Pathophysiology and Neuro-Imaging.

Posterior reversible encephalopathy syndrome (PRES) represents a unique clinical entity with non-specific clinical symptoms and unique neuroradiological findings. This syndrome may present with a broad range of clinical symptoms from headache and visual disturbances to seizure and altered mentation. Typical imaging findings include posterior-circulation predominant vasogenic edema. Although there are many well-documented diseases associated with PRES, the exact pathophysiologic mechanism has yet to be fully elucidated. Generally accepted theories revolve around disruption of the blood-brain barrier secondary to elevated intracranial pressures or endothelial injury. In this article, we will review the clinical, typical, and atypical radiological features of PRES, as well as the most common theories behind the pathophysiology of PRES. Additionally, we will discuss some of the treatment strategies for PRES related to the underlying disease state.

Common Data Elements in Head and Neck Radiology Reporting.

Radiologists must convert the complex information in head and neck imaging into text reports that can be understood and used by clinicians, patients, and fellow radiologists for patient care, research, and quality initiatives. Common data elements in reporting, through use of defined questions with constrained answers and terminology, allow radiologists to incorporate best practice standards and improve communication of information regardless of individual reporting style. Use of common data elements for head and neck reporting has the potential to improve outcomes, reduce errors, and transition data consumption not only for humans but future machine learning systems.

A de novo SIX1 variant in a patient with a rare nonsyndromic cochleovestibular nerve abnormality, cochlear hypoplasia, and bilateral sensorineural hearing loss.

BACKGROUND: Childhood hearing impairment affects language and cognitive development. Profound congenital sensorineural hearing impairment can be due to an abnormal cochleovestibular nerve (CVN) and cochleovestibular malformations, however, the etiology of these conditions remains unclear. METHODS: We used a trio-based exome sequencing approach to unravel the underlying molecular etiology of a child with a rare nonsyndromic CVN abnormality and cochlear hypoplasia. Clinical and imaging data were also reviewed. RESULTS: We identified a de novo missense variant [p(Asn174Tyr)] in the DNA-binding Homeodomain of SIX1, a gene which previously has been associated with autosomal dominant hearing loss (ADHL) and branchio-oto-renal or Branchio-otic syndrome, a condition not seen in this patient. CONCLUSIONS: SIX1 has an important function in otic vesicle patterning during embryogenesis, and mice show several abnormalities to their inner ear including loss of inner ear innervation. Previous reports on patients with SIX1 variants lack imaging data and nonsyndromic AD cases were reported to have no inner ear malformations. In conclusion, we show that a de novo variant in SIX1 in a patient with sensorineural hearing loss leads to cochleovestibular malformations and abnormalities of the CVN, without any other abnormalities. Without proper interventions, severe to profound hearing loss is devastating to both education and social integration. Choosing the correct intervention can be challenging and a molecular diagnosis may adjust intervention and improve outcomes, especially for rare cases.

Imaging of the Sella and Parasellar Region.

The sella and parasellar region, found between the anterior and central skull base, represents the central aspect of the skull base. Given the location of the pituitary gland in this location, small lesions in this location may have major physiologic effects on the human body. This article reviews the anatomy, development, and pathologic processes that may involve this region.

Ultra-High-Field Magnetic Resonance Imaging of the Human Inner Ear at 11.7 Tesla.

OBJECTIVE: To evaluate the ability of ultra-high-field magnetic resonance imaging (UHF-MRI) at 11.7 T to visualize membranous structures of the human inner ear. SPECIMENS: Three temporal bones were extracted from cadaveric human heads for use with small-bore UHF-MRI. INTERVENTION: Ex vivo cadaveric temporal bone specimens were imaged using an 11.7 T magnetic resonance imaging (MRI) scanner via T1- and T2-weighted-imaging with and without contrast. MAIN OUTCOME MEASURE: Qualitative visualization of membranous components of the inner ear compared with reports of UHF-MRI at lower field strengths. RESULTS: The membranous anatomy of the inner ear was superbly visualized at 11.7 T. In the cochlea, Reissner's membrane, the scala media, and the basilar membrane were clearly shown on the scan. In the vestibular labyrinth, the wedge-shaped crista ampullaris and the maculae of both the saccule and utricle were visible. Details of the endolymphatic sac and duct were also demonstrated. CONCLUSION: To our knowledge, this report presents the first images of the ex vivo human inner ear using 11.7 T UHF-MRI, offering near-histologic resolution. Increased field strength may be particularly useful when imaging the delicate membranous anatomy of the inner ear. Further research on the use of UHF-MRI in clinical and research settings could illuminate structural changes associated with inner ear disorders.

Quadruple Neoplasms following Radiation Therapy for Congenital Bilateral Retinoblastoma.

PURPOSE: The aim of this study was to describe a 34-year-old male with hereditary bilateral retinoblastoma treated with radiotherapy as a child who developed 4 distinct tumors within the radiation field. METHODS: A 34-year-old male with bilateral retinoblastoma status postradiation therapy and recurrence requiring enucleation presented with left-eye visual acuity changes. Magnetic resonance imaging demonstrated a left orbital mass and a right parasellar complex lobulated mass (right sphenoid and right cavernous sinus). Two weeks later, the patient underwent excision of the orbital mass and biopsy of an upper-lid nodule. This was followed by craniotomy for removal of the complex mass. RESULTS: Histology revealed 4 distinct tumors, including an undifferentiated pleomorphic sarcoma (left orbit), a radiation-induced meningioma (right sphenoid), a schwannoma (right cavernous sinus), and a basal-cell carcinoma (left lid). CONCLUSION: Although occurrence of a second neoplasm is a well-known outcome following radiation treatment in patients with hereditary retinoblastoma, the diagnosis of 4 additional neoplasms is rare. Pleomorphic sarcoma, radiation-induced meningioma, and schwannoma are uncommon tumors and not well represented in the literature describing irradiated retinoblastoma patients. Secondary malignancies are a leading cause of early death in retinoblastoma survivors, and long-term follow-up is crucial for patient care.

Imaging of primary central nervous system lymphoma.

Primary central nervous system lymphoma (PCNSL) is an aggressive neoplastic process that occurs in both immunocompetent and immunocompromised patients. Over the past 30 years there has been a steady increase in the number of cases in both patient populations. The imaging features for the disease and demographic characteristics within these patient populations vary, and in this article the authors describe the salient features of these two groups.

Multifocal granulocytic sarcoma of the spine mimicking neurofibromatosis Type 2: case report.

In this report the authors report on a patient with a very indolent course of granulocytic sarcoma, characterized by steroid-induced remission of spinal and cranial tumors and recurrence over a period of several years. This 24-year-old man with history of leukemia presented with rapid-onset quadriparesis secondary to multiple extraaxial masses of the cervicothoracic spine, from C-5 to T-3, and lumbosacral spine, from L-5 to the coccyx. Although the imaging features were highly suggestive of neurofibromatosis Type 2, the patient's history and clinical course were consistent with granulocytic sarcoma; repeat imaging and, later, needle biopsy definitively established the diagnosis of granulocytic sarcoma. Laminectomy and surgical decompression of the spine were not required and, arguably, could have posed unnecessary risk to the patient. This case illustrates that the successful management of a patient presenting with profound neurological deficits due to intradural spinal cord tumors may sometimes be nonsurgical.

Atypical central neurocytoma with metastatic craniospinal dissemination: a case report.

Central neurocytomas comprise nearly half of adult intraventricular neoplasms. The median age of onset is 34 years. It is typically a low-grade neoplasm (World Health Organization grade II), although some cases of malignant neurocytomas have been described. We present a rare case of an atypical central neurocytoma with craniospinal dissemination, including both imaging and pathologic findings.