Imaging of cranial nerves: a pictorial overview

Automatic segmentation and volume measurement of anterior visual pathway in brain 3D-T1WI using deep learning

Objective

Accurate anterior visual pathway (AVP) segmentation is vital for clinical applications, but manual delineation is time-consuming and resource-intensive. We aim to explore the feasibility of automatic AVP segmentation and volume measurement in brain T1-weighted imaging (T1WI) using the 3D UX-Net deep-learning model.

Methods

Clinical data and brain 3D T1WI from 119 adults were retrospectively collected. Two radiologists annotated the AVP course in each participant's images. The dataset was randomly divided into training (n = 89), validation (n = 15), and test sets (n = 15). A 3D UX-Net segmentation model was trained on the training data, with hyperparameters optimized using the validation set. Model accuracy was evaluated on the test set using Dice similarity coefficient (DSC), 95% Hausdorff distance (HD95), and average symmetric surface distance (ASSD). The 3D UX-Net's performance was compared against 3D U-Net, Swin UNEt TRansformers (UNETR), UNETR++, and Swin Soft Mixture Transformer (Swin SMT). The AVP volume in the test set was calculated using the model's effective voxel volume, with volume difference (VD) assessing measurement accuracy. The average AVP volume across all subjects was derived from 3D UX-Net's automatic segmentation.

Results

The 3D UX-Net achieved the highest DSC (0.893 ± 0.017), followed by Swin SMT (0.888 ± 0.018), 3D U-Net (0.875 ± 0.019), Swin UNETR (0.870 ± 0.017), and UNETR++ (0.861 ± 0.020). For surface distance metrics, 3D UX-Net demonstrated the lowest median ASSD (0.234 mm [0.188-0.273]). The VD of Swin SMT was significantly lower than that of 3D U-Net (p = 0.008), while no statistically significant differences were observed among other groups. All models exhibited identical HD95 (1 mm [1-1]). Automatic segmentation across all subjects yielded a mean AVP volume of 1446.78 ± 245.62 mm3, closely matching manual segmentations (VD = 0.068 ± 0.064). Significant sex-based volume differences were identified (p < 0.001), but no age correlation was observed.

Conclusion

We provide normative values for the automatic MRI measurement of the AVP in adults. The 3D UX-Net model based on brain T1WI achieves high accuracy in segmenting and measuring the volume of the AVP.

Leontiasis ossea in the setting of chronic kidney disease and limited dialysis access: A case report with discussion of therapeutic implications

Leontiasis ossea, also known as craniofacial fibrous dysplasia, is a rare form of osseous hypertrophy of the facial bones associated with chronic kidney disease and secondary hyperparathyroidism. As the condition progresses, changes in bone structure can lead to severe facial disfigurement, respiratory difficulties, dysarthria, and dysphagia. We describe the case of an approximately 30-year-old male with a long-standing history of end-stage renal disease who experienced rapidly progressing facial swelling and underlying bone changes following a period of poor access to dialysis. Despite brief symptomatic improvement following parathyroidectomy, the patient's hyperparathyroidism ultimately persisted. Subsequent immunomodulator therapy again offered subjective improvements but was discontinued in the setting of adverse effects. We provide a brief overview of the pathophysiology of leontiasis ossea, review imaging findings pertinent to the case presentation, and discuss relevant implications in the diagnosis and management of this disease.

Blind spots in brain imaging: a pictorial essay

Currently, radiologists must interpret large quantities of images and identify diseases on a daily basis. The minimization of errors is crucial for high-quality diagnostic imaging and optimal patient care. Brain imaging is frequently used in clinical practice; however, radiologists are prone to overlook some regions in brain imaging and make perceptual errors, thus leading to missed diagnoses. These regions, also known as "blind spots", comprise a number of intricate areas, including the posterior fossa, cerebral sulci and pia mater, cranial nerves (CNs), intracranial arteries, dural sinuses, sella and parasellar region, Meckel's cave, skull base, scalp, orbit, and pterygopalatine fossa (PPF). Therefore, the knowledge of normal computed tomography (CT) and magnetic resonance imaging (MRI) manifestations and common lesions in these blind spots is imperative to avoid false-negative results. This article graphically discusses and analyzes these common blind spots of brain imaging using real representative cases. It also provides comprehensive strategies to address missed diagnostic errors in radiology, including enhancing the selection of imaging protocols, implementing a multi-reviewer reporting system, adopting structured reporting templates, employing error measurement or detection strategies, and promoting the use, development, and refinement of artificial intelligence (AI) to improve diagnostic accuracy and efficiency. This article may also increase junior doctors' awareness of these blind spots and assist them in their daily work, and thus has continuing education implications.

Health-Related Quality of Life with Iatrogenic Inferior Alveolar Nerve Injuries Treated with Photobiomodulation: A Comparative Study

Background/Objectives: Photobiomodulation therapy (PBM) creates a biostimulatory or modulatory effect, promoting tissue regeneration and improving patients' health-related quality of life (HRQoL). PBM has shown promise as an effective treatment and management strategy for peripheral nerve injuries, including inferior alveolar nerve (IAN) damage. This study aims to assess the impact of PBM on HRQoL in patients with iatrogenic IAN injuries. Methods: A prospective study was implemented to investigate the research question. PBM treatments were administered weekly, with patient discharge contingent upon either complete recovery or stabilization of associated signs and symptoms. HRQoL was assessed using the EQ-5D-5L questionnaire at the initial and final appointments. Results: The study included 71 participants, divided into 3 groups based on etiology: inferior third molar surgery, mandibular orthognathic surgery, and dental implant surgery. The results showed a widespread reduction of symptoms along with a statistically significant improvement (p < 0.001) across four of the five dimensions of the EQ-5D-5L questionnaire, as well as in patients' perceived health levels in both Groups I and II. Group III patients also demonstrated a notable improvement; however, due to the small sample size, statistical analysis was not conducted for this group. Conclusions: PBM demonstrated a comparable ability to enhance HRQoL and alleviate symptoms in patients with IAN injuries within different etiologies. These findings underscore the effectiveness of the protocol used in this study and highlight potential avenues for expanding research in this field.

Neural Circuitries between the Brain and Peripheral Solid Tumors

The recent discovery of the pivotal role of the central nervous system in controlling tumor initiation and progression has opened a new field of research. Increasing evidence suggests a bidirectional interaction between the brain and tumors. The brain influences the biological behavior of tumor cells through complex neural networks involving the peripheral nervous system, the endocrine system, and the immune system, whereas tumors can establish local autonomic and sensory neural networks to transmit signals into the central nervous system, thereby affecting brain activity. This review aims to summarize the latest research in brain-tumor cross-talk, exploring neural circuitries between the brain and various peripheral solid tumors, analyzing the roles in tumor development and the related molecular mediators and pathologic mechanisms, and highlighting the critical impact on the understanding of cancer biology. Enhanced understanding of reciprocal communication between the brain and tumors will establish a solid theoretical basis for further research and could open avenues for repurposing psychiatric interventions in cancer treatment.

Pictorial Review of Cranial Nerve Denervation in the Head and Neck

Of the twelve cranial nerves, nine supply motor innervation to the muscles of the head and neck. Loss of this motor nerve supply, or denervation, follows a series of predictable chronologic changes in the affected muscles. Although the length of time between each change is markedly variable, denervation is typically classified into three distinct time points: (a) acute, (b) subacute, and (c) chronic. These muscle changes produce characteristic findings on images, with contrast-enhanced MRI being the preferred modality for assessment. Imaging allows radiologists to not only identify denervation but also evaluate the extent of denervation and localize the potential site of insult. However, these findings may be easily mistaken for other diseases with similar manifestations, such as neoplasm, infection, and inflammatory conditions. As such, it is fundamental for radiologists to be familiar with cranial nerve anatomy and denervation patterns so that they can avoid these potential pitfalls and focus their imaging search on the pathway of the affected nerve. In this article, the anatomy and muscles innervated by motor cranial nerves in the head and neck, denervation, and the associated expected imaging patterns are reviewed, and examples of potential pitfalls and denervation mimics are provided. ©RSNA, 2024.

Characterizing neuroinvasion and neuropathology of SARS-CoV-2 by using AC70 human ACE2 transgenic mice

COVID-19 presents with a plethora of neurological signs and symptoms despite being characterized as a respiratory disease, including seizures, anxiety, depression, amnesia, attention deficits, and alterations in consciousness. The olfactory nerve is widely accepted as the neuroinvasive route by which the etiological agent SARS-CoV-2 enters the brain, but the trigeminal nerve is an often-overlooked additional route. Based on this consensus, we initially conducted a pilot experiment investigating the olfactory nerve route of SARS-CoV-2 neuroinvasion via intranasal inoculation in AC70 human ACE2 transgenic mice. Notably, we found that the trigeminal ganglion is an early and highly efficient site of viral replication, which then rapidly spread widely throughout the brain where neurons were primarily targeted. Despite the extensive viral infection across the brain, obvious evidence of tissue pathology including inflammatory infiltration, glial activation, and apoptotic cell deaths were not consistently observed, albeit inflammatory cytokines were significantly induced. However, the expression levels of different genes related to neuronal function, including the neurotransmitter dopamine pathway as well as synaptic function, and markers of neuronal damage were altered as compared to mock-infected mice. Our findings suggest that the trigeminal nerve may serve as a neuroinvasive route complementary to the olfactory nerve and that the ensuing neuroinvasion presented a unique neuropathological profile. This study provides insights into potential neuropathogenic mechanisms utilized by coronaviruses.

Cellular and Molecular Effects of Magnetic Fields

Recently, magnetic fields (MFs) have received major attention due to their potential therapeutic applications and biological effects. This review provides a comprehensive analysis of the cellular and molecular impacts of MFs, with a focus on both in vitro and in vivo studies. We investigate the mechanisms by which MFs influence cell behavior, including modifications in gene expression, protein synthesis, and cellular signaling pathways. The interaction of MFs with cellular components such as ion channels, membranes, and the cytoskeleton is analyzed, along with their effects on cellular processes like proliferation, differentiation, and apoptosis. Molecular insights are offered into how MFs modulate oxidative stress and inflammatory responses, which are pivotal in various pathological conditions. Furthermore, we explore the therapeutic potential of MFs in regenerative medicine, cancer treatment, and neurodegenerative diseases. By synthesizing current findings, this article aims to elucidate the complex bioeffects of MFs, thereby facilitating their optimized application in medical and biotechnological fields.

Optic Nerve Imaging in Multiple Sclerosis and Related Disorders

Optic neuritis is a common feature in multiple sclerosis and in 2 other autoimmune demyelinating disorders such as aquaporin-4 IgG antibody-associated neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein antibody-associated disease. Although serologic testing is critical for differentiating these different autoimmune-mediated disorders, MR imaging, which is the preferred imaging modality for assessing the optic nerve, can provide valuable information, suggesting a specific diagnosis and guiding the appropriate serologic testing.

Facial and trigeminal nerves neuropathy induced by atmospheric pressure changes: A meta-analysis

BACKGROUND

Barometric pressure changes during flight or diving may cause facial barotrauma. Neuropathy of the fifth (CN5) or the seventh (CN7) cranial nerves is a rare manifestation of this condition. The aim of this study was to analyze risk factors for baroneuropathies of CN5 and CN7.

METHODS

A search of PubMed and Cochrane Library databases was conducted to identify all published cases of CN5 and CN7 neuropathies. Only original case reports and series that documented events of neuropathies associated with the trigeminal nerve or facial nerve while flying, diving, or mountain climbing were included. Assessed variables included sex, medical history, age, setting (flight or diving), atmospheric pressure changes, number of episodes, symptoms, treatment, and recovery.

RESULTS

We identified a total of 48 articles described >125 episodes in 67 patients. Mean age was 33.5 ± 12.1 years with a male predominance (76.1 %). Cases were equally distributed between flight and diving (50.7 %, 46.3 %, respectively). CN5 involvement was observed in 77.6 % of patients, with ear pain and facial numbness as the most common symptoms. The latter was correlated with positive otolaryngology medical history. CN7 was involved in 88.1 % of patients. Flying, as opposed to diving was correlated with spontaneous resolution of symptoms (86.7 % vs. 42.3 % of cases resolved spontaneously, respectively, p = 0.001).

CONCLUSIONS

Flight is an equal risk factor to diving with respect to CN5 and CN7 barotrauma. Involvement of CN7 was observed in most cases, but possibly due to report-bias. Positive medical history is a risk factor for facial numbness.

Sporadic pediatric vestibular schwannoma: a case report in a 4-year-old boy

Sporadic vestibular schwannomas (VSs) are rare in children. When occurred in the pediatric population, they usually appear bilaterally and are related to neurofibromatosis type 2 (NF2). The current study reports a 4-year-old boy without family history of VS or NF2 who presented with a large (5.7-cm) VS involving the right cerebellopontine angle and internal auditory canal. Through seven-staged surgical interventions and two stereotactic γ‑knife radiosurgery, the disease was stabilized. At 2-year follow-up, the child had right ear hearing loss, grade IV facial palsy, and normal motor function and gait. No definite evidence of gene mutation regarding NF2 can be identified after sequence analysis and deletion/duplication testing. This case highlights the significance of considering the possibility of sporadic VSs, even in very young children. It emphasizes the importance of not overlooking initial symptoms, as they may indicate the presence of a large tumor and could potentially result in delayed diagnosis.

Comparison between Ultrasonographic-Guided Temporal and Coronoid Approaches for Trigeminal Nerve Block in Dogs: A Cadaveric Study

The trigeminal nerve is responsible for innervating the periorbita. Ultrasound-guided trigeminal block is employed in humans for trigeminal neuralgia or periorbital surgery. There are no studies evaluating this block in dogs. This study aims to evaluate and compare two approaches (coronoid and temporal) of the trigeminal nerve block. We hypothesised superior staining with the coronoid approach. Thirteen dog heads were used. After a preliminary anatomical study, two ultrasound-guided injections per head (right and left, coronoid and temporal approach, randomly assigned), with an injectate volume of 0.15 mL cm-1 of cranial length, were performed (iodinated contrast and tissue dye mixture). The ultrasound probe was placed over the temporal region, visualising the pterygopalatine fossa. For the temporal approach, the needle was advanced from the medial aspect of the temporal region in a dorsoventral direction. For the coronoid approach, it was advanced ventral to the zygomatic arch in a lateromedial direction. CT scans and dissections were conducted to assess and compare the position of the needle, the spread of the injectate, and nerve staining. No significant differences were found. Both approaches demonstrated the effective interfascial distribution of the injectate, with some minimal intracranial spread. Although the coronoid approach did not yield superior staining as hypothesised, it presents a viable alternative to the temporal approach. Studies in live animals are warranted to evaluate clinical efficacy and safety.

Utility of MR Neurography for the Evaluation of Peripheral Trigeminal Neuropathies in the Postoperative Period

Peripheral trigeminal neuropathies are assessed by MR neurography for presurgical mapping. In this clinical report, we aimed to understand the utility of MR neurography following nerve-repair procedures. We hypothesized that postoperative MR neurography assists in determining nerve integrity, and worsening MR neurography findings will corroborate poor patient outcomes. Ten patients with peripheral trigeminal neuropathy were retrospectively identified after nerve-repair procedures, with postsurgical MR neurography performed from July 2015 to September 2023. Postsurgical MR neurography findings were graded as per postintervention category and subcategories of the Neuropathy Score Reporting and Data System (NS-RADS). Descriptive statistics of demographics, inciting injury, injury severity, NS-RADS scoring, and clinical outcomes were obtained. There were 6 women and 4 men (age range, 25-73 years). Most injuries resulted from third molar removals (8/10), with an average time from the inciting event to nerve-repair surgery of 6.1 (SD, 4.6) months. In Neuropathy Score Reporting and Data System-Injury (NS-RADS I), NS-RADS I-4 injuries (neuroma in continuity) were found in 8/10 patients, and NS-RADS I-5 injuries were found in the remaining patients, all confirmed at surgery. Surgeries performed included microdissection with neurolysis, neuroma excision, and nerve allograft with Axoguard protection. Three patients with expected postsurgical MR neurography findings experienced either partial improvement or complete symptom resolution, while among 7 patient with persistent or recurrent neuropathy on postsurgical MR neurography, one demonstrated partial improvement of sensation, pain, and taste and one experienced only pain improvement; the remaining 5 patients demonstrated no improvement. Postsurgical MR neurography consistently coincided with clinical outcomes related to pain, sensation, and lip biting and speech challenges. Lip biting and speech challenges were most amenable to recovery, even with evidence of persistent nerve pathology on postsurgical MR neurography.

Outcome of patients with traumatic cranial nerve palsy admitted to a university hospital in Nepal

BACKGROUND

Cranial nerve palsy (CNP) is a common complication of traumatic brain injury (TBI). Despite a high incidence of TBI in Nepal (382 per 100,000), literature on the specific management and outcome of CNP is lacking. This study aimed to examine the outcomes of TBI patients involving single versus multiple CNP.

METHODS

A retrospective chart review of 170 consecutive TBI patients admitted to the tertiary neurosurgical center in Nepal between April 2020 and April 2022 was conducted. Demographic, clinical, and etiological characteristics; imaging findings; and management strategies were recorded, compared, and analyzed using descriptive statistics. The Glasgow Outcome Scale Extended (GOSE) was used to measure the outcomes in two groups of patients (single and multiple CNP) at 3 months.

RESULTS

Out of 250 eligible patients, 80 were excluded and CNP was noted in 29 (17.1%) of the remaining 170. The median age was 34.9 years, and falls (60.6%) were the most common cause of trauma. TBI severity was categorized based on GCS: mild (82.4%), moderate (15.9%), and severe (1.8%). Cranial nerve involvement was seen in 29 (17.05%) patients: single cranial nerve involvement in 26 (89.65%) and multiple nerve involvement in 3 (10.34%). The most common isolated cranial nerve involved was the oculomotor nerve (37.9%). CT findings revealed a maximum of skull fractures with no significant association between CNP and CT findings.

CONCLUSIONS

CNP is a common consequence of TBI with the most common etiology being falls followed by RTA. Single CNP was more common than multiple CNP with no significant difference in the outcome in the 3-month GOSE score. Further research is needed to determine the burden of traumatic CNP and establish specific management guidelines for different types of CNP.

Discontinuity third harmonic generation microscopy for label-free imaging and quantification of intraepidermal nerve fibers

Label-free imaging methodologies for nerve fibers rely on spatial signal continuity to identify fibers and fail to image free intraepidermal nerve endings (FINEs). Here, we present an imaging methodology-called discontinuity third harmonic generation (THG) microscopy (dTHGM)-that detects three-dimensional discontinuities in THG signals as the contrast. We describe the mechanism and design of dTHGM and apply it to reveal the bead-string characteristics of unmyelinated FINEs. We confirmed the label-free capability of dTHGM through a comparison study with the PGP9.5 immunohistochemical staining slides and a longitudinal spared nerve injury study. An intraepidermal nerve fiber (IENF) index based on a discontinuous-dot-connecting algorithm was developed to facilitate clinical applications of dTHGM. A preliminary clinical study confirmed that the IENF index was highly correlated with skin-biopsy-based IENF density (Pearson's correlation coefficient R = 0.98) and could achieve differential identification of small-fiber neuropathy (p = 0.0102) in patients with diabetic peripheral neuropathy.

On the Cranial Nerves

The twelve cranial nerves play a crucial role in the nervous system, orchestrating a myriad of functions vital for our everyday life. These nerves are each specialized for particular tasks. Cranial nerve I, known as the olfactory nerve, is responsible for our sense of smell, allowing us to perceive and distinguish various scents. Cranial nerve II, or the optic nerve, is dedicated to vision, transmitting visual information from the eyes to the brain. Eye movements are governed by cranial nerves III, IV, and VI, ensuring our ability to track objects and focus. Cranial nerve V controls facial sensations and jaw movements, while cranial nerve VII, the facial nerve, facilitates facial expressions and taste perception. Cranial nerve VIII, or the vestibulocochlear nerve, plays a critical role in hearing and balance. Cranial nerve IX, the glossopharyngeal nerve, affects throat sensations and taste perception. Cranial nerve X, the vagus nerve, is a far-reaching nerve, influencing numerous internal organs, such as the heart, lungs, and digestive system. Cranial nerve XI, the accessory nerve, is responsible for neck muscle control, contributing to head movements. Finally, cranial nerve XII, the hypoglossal nerve, manages tongue movements, essential for speaking, swallowing, and breathing. Understanding these cranial nerves is fundamental in comprehending the intricate workings of our nervous system and the functions that sustain our daily lives.

The application value of LAVA-flex sequences in enhanced MRI scans of nasopharyngeal carcinoma: comparison with T1WI-IDEAL

Introduction

Magnetic resonance imaging (MRI) staging scans are critical for the diagnosis and treatment of patients with nasopharyngeal cancer (NPC). We aimed to evaluate the application value of LAVA-Flex and T1WI-IDEAL sequences in MRI staging scans.

Methods

Eighty-four newly diagnosed NPC patients underwent both LAVA-Flex and T1WI-IDEAL sequences during MRI examinations. Two radiologists independently scored the acquisitions of image quality, fat suppression quality, artifacts, vascular and nerve display. The obtained scores were compared using the Wilcoxon signed rank test. According to the signal intensity (SI) measurements, the uniformity of fat suppression, contrast between tumor lesions and subcutaneous fat tissue, and signal-to-noise ratio (SNR) were compared by the paired t-test.

Results

Compared to the T1WI-IDEAL sequence, LAVA-Flex exhibited fewer artifacts (P<0.05), better visualization of nerves and vessels (P<0.05), and performed superior in the fat contrast ratio of the primary lesion and metastatic lymph nodes (0.80 vs. 0.52, 0.81 vs. 0.56, separately, P<0.001). There was no statistically significant difference in overall image quality, tumor signal-to-noise ratio (SNR), muscle SNR, and the detection rate of lesions between the two sequences (P>0.05). T1WI-IDEAL was superior to LAVA-Flex in the evaluation of fat suppression uniformity (P<0.05).

Discussion

LAVA-Flex sequence provides satisfactory image quality and better visualization of nerves and vessels for NPC with shorter scanning times.

Understanding Visual Disorders through Correlation of Clinical and Radiologic Findings

Patients presenting with visual disturbances often require a neuroimaging approach. The spectrum of visual disturbances includes three main categories: vision impairment, ocular motility dysfunction, and abnormal pupillary response. Decreased vision is usually due to an eye abnormality. However, it can also be related to other disorders affecting the visual pathway, from the retina to the occipital lobe. Ocular motility dysfunction may follow disorders of the cranial nerves responsible for eye movements (ie, oculomotor, trochlear, and abducens nerves); may be due to any abnormality that directly affects the extraocular muscles, such as tumor or inflammation; or may result from any orbital disease that can alter the anatomy or function of these muscles, leading to diplopia and strabismus. Given that pupillary response depends on the normal function of the sympathetic and parasympathetic pathways, an abnormality affecting these neuronal systems manifests, respectively, as pupillary miosis or mydriasis, with other related symptoms. In some cases, neuroimaging studies must complement the clinical ophthalmologic examination to better assess the anatomic and pathologic conditions that could explain the symptoms. US has a major role in the assessment of diseases of the eye and anterior orbit. CT is usually the first-line imaging modality because of its attainability, especially in trauma settings. MRI offers further information for inflammatory and tumoral cases. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Cranial Nerve Thinning Distinguishes RFC1-Related Disorder from Other Late-Onset Ataxias

BACKGROUND

RFC1-related disorder (RFC1/CANVAS) shares clinical features with other late-onset ataxias, such as spinocerebellar ataxias (SCA) and multiple system atrophy cerebellar type (MSA-C). Thinning of cranial nerves V (CNV) and VIII (CNVIII) has been reported in magnetic resonance imaging (MRI) scans of RFC1/CANVAS, but its specificity remains unclear.

OBJECTIVES

To assess the usefulness of CNV and CNVIII thinning to differentiate RFC1/CANVAS from SCA and MSA-C.

METHODS

Seventeen individuals with RFC1/CANVAS, 57 with SCA (types 2, 3 and 6), 11 with MSA-C and 15 healthy controls were enrolled. The Balanced Fast Field Echo sequence was used for assessment of cranial nerves. Images were reviewed by a neuroradiologist, who classified these nerves as atrophic or normal, and subsequently the CNV was segmented manually by an experienced neurologist. Both assessments were blinded to patient and clinical data. Non-parametric tests were used to assess between-group comparisons.

RESULTS

Atrophy of CNV and CNVIII, both alone and in combination, was significantly more frequent in the RFC1/CANVAS group than in healthy controls and all other ataxia groups. Atrophy of CNV had the highest sensitivity (82%) and combined CNV and CNVIII atrophy had the best specificity (92%) for diagnosing RFC1/CANVAS. In the quantitative analyses, CNV was significantly thinner in the RFC1/CANVAS group relative to all other groups. The cutoff CNV diameter that best identified RFC1/CANVAS was ≤2.2 mm (AUC = 0.91; sensitivity 88.2%, specificity 95.6%).

CONCLUSION

MRI evaluation of CNV and CNVIII using a dedicated sequence is an easy-to-use tool that helps to distinguish RFC1/CANVAS from SCA and MSA-C.

Extra-axial cranial nerve enhancement: a pattern-based approach

Cranial nerve enhancement is a common and challenging MRI finding that requires a meticulous and systematic evaluation to identify the correct diagnosis. Literature mainly describes the various pathologies with the associated clinic-radiological characteristics, while the radiologist often needs a reverse approach that starts from the radiological findings to reach the diagnosis. Therefore, our aim is to provide a new and practical pattern-based approach to cranial nerve enhancement, which starts from the radiological findings and follows pattern-driven pipelines to navigate through multiple differential diagnoses, guiding the radiologist to reach the proper diagnosis. Firstly, we reviewed the literature and identified four patterns to categorize the main pathologies presenting with cranial nerve enhancement: unilateral linear pattern, bilateral linear pattern, unilateral thickened pattern, and bilateral thickened pattern. For each pattern, we describe the underlying pathogenic origin, and the main radiological features are displayed through high-quality MRI images and illustrative panels. A suggested MRI protocol for studying cranial nerve enhancement is also provided. In conclusion, our approach for cranial nerve enhancement aims to be an easy tool immediately applicable to clinical practice for converting challenging findings into specific pathological patterns.

The value of 3D high-resolution IR-prepared fast spoiled gradient-recalled MRI in the diagnosis of meningeal carcinomatosis involving the cranial nerves

PURPOSE

The purpose of this study was to investigate the clinical utility of three-dimension (3D) high-resolution inversion recovery (IR)-prepared fast spoiled gradient-recalled (SPGR) magnetic resonance imaging (MRI) in the diagnosis of cranial nerve meningeal carcinomatosis (MC).

METHODS

A total of 114 patients with MC from January 2015 to March 2020 were enrolled and their MRIs were analyzed retrospectively. All patients underwent MRIs before being administered a contrast agent. Both a 2D conventional MRI sequence and a 3D IR-prepared fast SPGR high-resolution T1-weighted (BRAVO) scan sequence were measured after contrast agent administration. The characteristics of MC and the involved cranial nerves were then examined.

RESULTS

Among the 114 MC patients, 81 (71.05%) had cranial nerve enhancement on contrast-enhanced 3D-BRAVO imaging, while only 41 (35.96%) had image enhancement on conventional MRI. The contrast-enhanced 3D-BRAVO displayed stronger image contrast enhancement of the cranial nerves than the conventional MRI (P < 0.001). Furthermore, detection rates for the facial and auditory nerves, trigeminal nerve, oculomotor nerve, sublingual nerve, optic nerve, glossopharyngeal/vagal/accessory nerve, and abductor nerve on contrast-enhanced 3D-BRAVO imaging were 58.77%, 47.37%, 9.65%, 8.77%, 5.26%, 3.51%, and 0.88%, respectively. We found a statistically significant difference between the affected facial and auditory nerves, as well as the trigeminal nerve, oculomotor nerve, sublingual nerve, and optic nerve.

CONCLUSION

In MC, contrast-enhanced 3D-BRAVO imaging displayed the cranial nerves more effectively than 2D conventional enhanced MRI. The facial, auditory, and trigeminal nerves are the primary nerves involved in MC, and improved scanning of these nerves would aid in the early detection and treatment of MC.

Uninterrupted real-time cerebral stress level monitoring using wearable biosensors: A review

Stress is the major unseen bug for the health of humans with the increasing workaholic era. Long periods of avoidance are the main precursor for chronic disorders that are quite tough to treat. As precaution is better than cure, stress detection and monitoring are vital. Although there are ways to measure stress clinically, there is still a constant need and demand for methods that measure stress personally and in an ex vitro manner for the convenience of the user. The concept of continuous stress monitoring has been introduced to tackle the issue of unseen stress accumulating in the body simultaneously with being user-friendly and reliable. Stress biosensors nowadays provide real-time, noninvasive, and continuous monitoring of stress. These biosensors are innovative anthropogenic creations that are a combination of biomarkers and indicators like heart rate variation, electrodermal activity, skin temperature, galvanic skin response, and electroencephalograph of stress in the body along with machine learning algorithms and techniques. The collaboration of biological markers, artificial intelligence techniques, and data science tools makes stress biosensors a hot topic for research. These attributes have made continuous stress detection a possibility with ease. The advancement in stress biosensing technologies has made a great impact on the lives of human beings so far. This article focuses on the comprehensive study of stress-indicating biomarkers and the techniques along with principles of the biosensors used for continuous stress detection. The precise overview of wearable stress monitoring systems is also sectioned to pave a pathway for possible future research studies.

Gut-to-brain spreading of pathology in synucleinopathies: A focus on molecular signalling mediators

Synucleinopathies are a group of neurodegenerative disorders, classically characterized by the accumulation of aggregated alpha synuclein (aSyn) in the central nervous system. Parkinson's disease (PD) and multiple system atrophy (MSA) are the two prominent members of this family. Current treatment options mainly focus on the motor symptoms of these diseases. However, non-motor symptoms, including gastrointestinal (GI) symptoms, have recently gained particular attention, as they are frequently associated with synucleinopathies and often arise before motor symptoms. The gut-origin hypothesis has been proposed based on evidence of an ascending spreading pattern of aggregated aSyn from the gut to the brain, as well as the comorbidity of inflammatory bowel disease and synucleinopathies. Recent advances have shed light on the mechanisms underlying the progression of synucleinopathies along the gut-brain axis. Given the rapidly expanding pace of research in the field, this review presents a summary of the latest findings on the gut-to-brain spreading of pathology and potential pathology-reinforcing mediators in synucleinopathies. Here, we focus on 1) gut-to-brain communication pathways, including neuronal pathways and blood circulation, and 2) potential molecular signalling mediators, including bacterial amyloid proteins, microbiota dysbiosis-induced alterations in gut metabolites, as well as host-derived effectors, including gut-derived peptides and hormones. We highlight the clinical relevance and implications of these molecular mediators and their possible mechanisms in synucleinopathies. Moreover, we discuss their potential as diagnostic markers in distinguishing the subtypes of synucleinopathies and other neurodegenerative diseases, as well as for developing novel individualized therapeutic options for synucleinopathies.

The Vestibulocochlear Nerve: Anatomy and Pathology

The vestibulocochlear nerve is the eighth cranial nerve, entering the brainstem in the medullopontine sulcus after crossing the internal auditory canal and cerebellopontine angle cistern. It is a purely sensitive nerve, originating from the Scarpa's and spiral ganglions, responsible for balance and hearing. It has 6 nuclei located in the lower pons. Magnetic resonance imaging (MRI) is useful for evaluating the vestibulocochlear nerve, although computed tomography may have a complementary role in assessing bone lesions. A heavily T2-weighted sequence, such as fast imaging employing steady-state acquisition (FIESTA) or constructive interference steady state (CISS), is crucial in imaging exams to depict the canalicular and cisternal segments of the vestibulocochlear nerve, as well as the fluid signal intensity in the membranous labyrinth. The vestibulocochlear nerve can be affected by several diseases, such as congenital malformations, trauma, inflammatory or infectious diseases, vascular disorders, and neoplasms. The purpose of this article is to review the vestibulocochlear nerve anatomy, discuss the best MRI techniques to evaluate this nerve and demonstrate the imaging aspect of the main diseases that affect it.

Facial nerve in skullbase tumors: imaging and clinical relevance

Facial nerve, the 7th cranial nerve, is a mixed nerve composed of sensory and motor fibers, and its main branch is situated in the cerebellopontine angle. Facial nerve dysfunction is a debilitating phenomenon that can occur in skullbase tumors and Bell's pals. Recovery of the facial nerve dysfunction after surgery for skullbase tumors can be disappointing, but is usually favorable in Bell's palsy. Advances in magnetic resonance imaging (MRI) allow to visualize the facial nerve and its course in the cerebellopontine angle, also when a large tumor is present and compresses the nerve. Here, we describe the anatomical, neurochemical and clinical aspects of the facial nerve and highlight the recent progress in visualizing the facial nerve with MRI.

Imaging of brain metastasis in non-small-cell lung cancer: indications, protocols, diagnosis, post-therapy imaging, and implications regarding management

Increased survival (due to the use of targeted therapies based on genomic profiling) has resulted in the increased incidence of brain metastasis during the course of disease, and thus, made it essential to have proper imaging guidelines in place for brain metastasis from non-small-cell lung cancer (NSCLC). Brain parenchymal metastases can have varied imaging appearances, and it is pertinent to be aware of the various molecular risk factors for brain metastasis from NSCLC along with their suggestive imaging appearances, so as to identify them early. Leptomeningeal metastasis requires additional imaging of the spine and an early cerebrospinal fluid (CSF) analysis. Differentiation of post-therapy change from recurrence on imaging has a bearing on the management, hence the need for its awareness. This article will provide in-depth literature review of the epidemiology, aetiopathogenesis, screening, detection, diagnosis, post-therapy imaging, and implications regarding the management of brain metastasis from NSCLC. In addition, we will also briefly highlight the role of artificial intelligence (AI) in brain metastasis screening.

Bilateral peripheric facial nerve palsy following SARS-CoV-2 infection: A case report and review of literature

Neurologic complications of SARS-CoV-2 infection have been reported commonly. Peripheric facial nerve palsy is one of the most reported neurologic problems. However, idiopathic bilateral facial palsy is a very rare complication of SARS-CoV-2 infection. Herein, we present a case of a COVID-19 35-year-old man, which developed bilateral facial palsy.

Isolated congenital facial nerve agenesis

An otherwise healthy 2 month old boy was referred to ENT for a congenital right facial palsy, with a birth history of difficult ventouse delivery. Initially, a traumatic cause was suspected, however subsequent MR 3D-FIESTA (T2 weighted) imaging demonstrated a right facial nerve agenesis with normal appearances of the remainder of the brain parenchyma, cranial nerves and parotid glands. There were no syndromic features or hearing difficulties. Isolated congenital nerve agenesis is a rare condition, with very few case reports available in the literature. Pre-natal 4D ultrasound imaging further supports the diagnosis. To our knowledge, this is the first published pre-natal ultrasound image of congenital facial nerve palsy. The infant has been referred for consideration of nerve reconstruction surgery, and is receiving multi-disciplinary input from ENT, Physiotherapy and Ophthalmology, the latter for prevention of exposure keratitis.

Cranial nerve involvement in mucormycosis in post-COVID patients: a case series

Background

One of the largest outbreaks of rhinosinocerebral mucormycosis (RSCM) occurred in India close to the second wave of the SARS-CoV-2 infection. RSCM is a rare infection caused by several fungal species occurring in immunocompromised subjects. Mucor shows a high propensity to invade the central nervous system. There have been limited studies, mostly isolated case reports, on the neurological manifestations of RSCM. The outbreak of mucormycosis infection was thus the most opportune to study the neurological manifestations and cranial nerve involvement in mucormycosis in greater depths.

Aim of the study

The purpose of the study was to investigate and review the involvement of cranial nerves in a series of cases of rhinosinocerebral mucormycosis associated with the novel coronavirus disease caused by SARS-CoV-2.

Results

It was a retrospective cross-sectional study of seven patients who were undergoing treatment of RSCM with a recent history of coronavirus disease caused by SARS-CoV-2 infection within the last 3 months. Patients with cranial nerve involvement were identified by magnetic resonance imaging (MRI) at a single institution. Demographic details of the patients, clinical presentation, imaging, microbiological and pathological findings were recorded. All subjects had two or more cranial nerves affected by fungal infection. The most commonly involved cranial nerve was found to be the optic nerve followed by the trigeminal nerve and its branches. We document three cases with extensive involvement of the inferior alveolar branch of the mandibular division of the trigeminal nerve (V3), a previously unreported finding. In one case, in addition to the second and fifth cranial nerves, the third, fourth, sixth, seventh, eighth, and twelfth cranial nerves were involved without any sensory or motor long tract involvement, suggestive of Garcin syndrome secondary to intracranial abscesses and skull base osteomyelitis due to invasive fungal infection. This case is of rare occurrence in the literature, and our study provides one such example.

Conclusion

Cranial nerve involvement in patients of mucormycosis tends to have a poor prognosis, both cosmetic and functional. Radical surgeries and aggressive medical management is needed in such cases to improve the outcome.

Orbital intraconal abducens nerve schwannoma: An interdisciplinary approach for management

Schwannomas are rare benign tumors arising from Schwann cells of the nerve sheath. Although the head-and-neck region accounts for a large percentage of extracranial schwannomas, those located within the orbit are infrequent. This paper presents an extremely rare case of orbital schwannoma arising from the terminal branch of abducens nerve in a 37-year-old female. The lesion presented as a large intraconal mass causing proptosis and weakness to abduct the left eye. Imaging showed a well-defined, solid-cystic lesion, measuring 2.7 cm and displacing the lateral rectus muscle laterally and the optic nerve medially. A multidisciplinary approach was used for the surgical management of the tumor. Access was attained through lateral rim osteotomy. Histopathological evaluation was diagnostic for schwannoma. A search of English literature revealed only five previously published cases of abducens nerve schwannomas. A review of these cases has also been discussed along with the present report.

Guillain-Barré Syndrome Presenting as Facial Diplegia after COVID-19 Vaccination: A Case Report

Background: Guillain-Barré Syndrome (GBS) is a rapidly progressive immune-mediated polyneuropathy often associated with an antecedent infectious illness or vaccination. The classic presentation of GBS is characterized by ascending limb weakness and numbness with loss of reflexes. However, atypical variants involving the face and arms or with purely sensory symptoms also exist. In up to 30% of cases, GBS progresses to respiratory failure, with patients requiring mechanical ventilation.

Case Report: We report a case of atypical GBS occurring after Coronavirus disease 2019 (COVID-19) vaccination in an otherwise healthy 38-year-old man. The patient's clinical presentation was characterized by bilateral hand and foot paresthesias, dysarthria, bilateral facial weakness, and an absence of classic ascending limb weakness. Albuminocytological dissociation within the cerebrospinal fluid was suggestive of GBS. The patient received intravenous immunoglobulin therapy, with modest improvement in his symptoms at the time of his discharge from the hospital.

Why Should an Emergency PhysicianBe Aware of This? Patients with GBS are at risk for life-threatening complications, including respiratory failure requiring mechanical ventilation. It is critical for emergency physicians to be aware of the manifold presentations of GBS for early recognition and treatment. This may be of particular importance in the context of a worldwide vaccination campaign in response to the COVID-19 pandemic.

Magnetic resonance imaging of the cranial nerves in congenital, traumatic, and vascular diseases: a pictorial essay

The cranial nerves, which represent extensions of the functional structures of the brain, traverse the head and neck. They are connected to various cranial structures and are associated with several diseases. An in-depth understanding of their complex anatomy and normal imaging appearance allows the examiner to identify and characterize abnormalities with greater precision. One important tool for evaluating the cranial nerves is contrast-enhanced magnetic resonance imaging, especially three-dimensional steady-state free precession sequences, which provide high soft-tissue and spatial resolution, despite the slenderness of the nerves. In most cases, imaging findings are nonspecific. Therefore, to narrow the differential diagnosis, it is necessary to take a full patient anamnesis, perform a focused physical examination and order laboratory tests. In this pictorial essay we review, illustrate and discuss, from a pathophysiological perspective, congenital, traumatic, and vascular diseases of the cranial nerves.

Imaging of intracranial fat: from normal findings to pathology

The presence of intracranial adipose tissue is often overlooked, although it may be detected in different physiological (dural sinuses or falx deposition of fat) and pathological (lipoma, dermoid cyst, subarachnoid fat dissemination) conditions. In this review, we illustrate various scenarios in which radiologists and neuroradiologists may encounter intracranial fat, providing a list of differential diagnosis.

Central Skull Base Anatomy and Pathology: A Review

The central skull base is an anatomically complex region of the head and neck which hosts a variety of neoplastic, vascular, infectious, inflammatory, and developmental pathologies. Evaluation of its intricate anatomy requires dedicated and complementary imaging modalities of MRI and CT. This article will provide a brief review of the anatomy of the central skull base, followed by an overview of common pathologies encountered in this region and their characteristic radiological characteristics.

Improved Lesion Conspicuity with Contrast-Enhanced 3D T1 TSE Black-Blood Imaging in Cranial Neuritis: A Comparative Study of Contrast-Enhanced 3D T1 TSE, 3D T1 Fast-Spoiled Gradient Echo, and 3D T2 FLAIR

BACKGROUND AND PURPOSE

Contrast-enhanced 3D-turbo spin-echo (TSE) black-blood sequence has gained attention, as it suppresses signals from vessels and provides an increased contrast-noise ratio. The purpose was to investigate which among the contrast-enhanced 3D T1 TSE, 3D T1 fast-spoiled gradient echo (FSPGR), and 3D T2 FLAIR sequences can better detect cranial nerve contrast enhancement.

MATERIALS AND METHODS

Patients with cranial neuritis based on clinical findings (n = 20) and control participants (n = 20) were retrospectively included in this study. All patients underwent 3T MR imaging with contrast-enhanced 3D T1 TSE, 3D T1 FSPGR, and 3D T2 FLAIR. Experienced and inexperienced reviewers independently evaluated the 3 sequences to compare their diagnostic performance and time required to reach the diagnosis. Additionally, tube phantoms containing varying concentrations of gadobutrol solution were scanned using the 3 sequences.

RESULTS

For the inexperienced reader, the 3D T1 TSE sequence showed significantly higher sensitivity (80% versus 50%, P = .049; 80% versus 55%; P = .040), specificity (100% versus 65%, P = .004; 100% versus 60%; P = .001), and accuracy (90% versus 57.5%, P = .001; 90% versus 57.5%, P = .001) than the 3D T1 FSPGR and 3D T2 FLAIR sequences in patients with cranial neuritis. For the experienced reader, the 3D T1-based sequences showed significantly higher sensitivity than the 3D T2 FLAIR sequence (85% versus 30%, P < .001; 3D T1 TSE versus 3D T2 FLAIR, 85% versus 30%, P < .001; 3D T1 FSPGR versus 3D T2 FLAIR). For both readers, the 3D T1 TSE sequence showed the highest area under the curve (inexperienced reader; 0.91, experienced reader; 0.87), and time to diagnosis was significantly shorter with 3D T1 TSE than with 3D T1 FSPGR.

CONCLUSIONS

The 3D T1 TSE sequence may be clinically useful in evaluating abnormal cranial nerve enhancement, especially for inexperienced readers.

Olfactory Neuroblastoma of the Sinonasal Tract with Prominent Orbital Protrusion: A Case Report and Literature Review

Olfactory neuroblastoma (ONB) is a rare malignant neuroectodermal tumor of the nasal cavity. Olfactory neuroblastoma centered in the posterior right orbit with prominent orbital protrusion is even rare. Grading ONB is extremely important as individualized treatment plans must be formulated according to tumor grade. We report the case of a 67-year-old female who presented with the chief complaints of persistent nasal congestion with intermittent epistaxis and unilateral proptosis over the past five years. Radiological imaging was suggestive of a large heterogeneous mass in the right superior nasal cavity with extensions into the right medial orbit, nasopharynx, the right maxillary sinus, the anterior cranial fossa, right ethmoidal, frontal and bilateral sphenoidal sinuses, as well as into the right frontal lobe. Assessment of the radiologic features revealed the diagnostic possibility of olfactory neuroblastoma. A nasopharyngeal biopsy confirmed an olfactory neuroblastoma. Frontal osteoplastic craniotomy and excision of the intracranial part of the tumor from above and transnasal endoscopic removal of the mass in the nasal cavities, paranasal sinuses and right medial orbit from below was done. Evaluation of histopathological characteristics and immunohistochemical findings revealed a diagnosis of WHO grade IV olfactory neuroblastoma. Because of poor economic condition, the patient did not take adjuvant radiotherapy and chemoradiation and post-operative examination. We report a huge ONB centered in the posterior right orbit with prominent orbital protrusion. Magnetic resonance image and computed tomography are helpful for evaluating the appearance and the extent of ONB, as well as grading this tumor, which may aid therapeutic decisions and improve survival.

3D Cranial Nerve Imaging, a Novel MR Neurography Technique Using Black-Blood STIR TSE with a Pseudo Steady-State Sweep and Motion-Sensitized Driven Equilibrium Pulse for the Visualization of the Extraforaminal Cranial Nerve Branches

This study investigated the feasibility of a 3D black-blood STIR TSE sequence with a pseudo steady-state sweep and motion-sensitized driven equilibrium pulse for extraforaminal cranial nerve imaging on a 3T system. Assessments of healthy volunteers showed near-perfect agreement in nerve visualization with excellent to good visualization of the extraforaminal trigeminal, greater occipital, and facial nerves. Suppression of surrounding tissues was excellent to good. 3D cranial nerve imaging can produce nerve selective imaging of extraforaminal cranial and spinal nerve branches.

High-resolution magnetic resonance imaging in isolated, traumatic oculomotor nerve palsy: A case report

Traumatic, isolated oculomotor nerve palsy is a rare clinical finding and only few reports demonstrate associated magnetic resonance imaging (MRI) findings. Here, we present the case of a 70-year-old woman with left-sided oculomotor nerve palsy following a mild head trauma due to an e-bike accident. Post-traumatic cerebral computed tomography revealed punctiform hemorrhage in the left interpeduncular cistern and the following MRI confirmed an intraneural hemorrhage of the left oculomotor nerve. Nine weeks later, the follow-up MRI showed progressive atrophy and contrast-enhancement of the left oculomotor nerve. To support functional recovery, a treatment with intravenous corticosteroids was started. Six months later, the patient presented with improved oculomotor nerve function and partial recovery of ptosis and diplopia. In accordance, MRI demonstrated recurrent contrast-enhancement of the atrophic nerve. In conclusion, high-resolution MRI allows the reliable delineation of the oculomotor nerve and can support diagnosis in trauma patients with isolated oculomotor nerve palsy.

A novel hypothesis on metal dyshomeostasis and mitochondrial dysfunction in amyotrophic lateral sclerosis: Potential pathogenetic mechanism and therapeutic implications

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder characterized by motor dysfunctions resulting from the loss of upper (UMNs) and lower (LMNs) motor neurons. While ALS symptoms are coincidental with pathological changes in LMNs and UMNs, the causal relationship between the two is unclear. For example, research on the extra-motor symptoms associated with this condition suggests that an imbalance of metals, including copper, zinc, iron, and manganese, is initially induced in the sensory ganglia due to a malfunction of metal binding proteins and transporters. It is proposed that the resultant metal dyshomeostasis may promote mitochondrial dysfunction in the satellite glial cells of these sensory ganglia, causing sensory neuron disturbances and sensory symptoms. Sensory neuron hyperactivation can result in LMN impairments, while metal dyshomeostasis in spinal cord and brain stem parenchyma induces mitochondrial dysfunction in LMNs and UMNs. These events could prompt intracellular calcium dyshomeostasis, pathological TDP-43 formation, and reactive microglia with neuroinflammation, which in turn activate the apoptosis signaling pathways within the LMNs and UMNs. Our model suggests that the degeneration of LMNs and UMNs is incidental to the metal-induced changes in the spinal cord and brain stem. Over time psychiatric symptoms may appear as the metal dyshomeostasis and mitochondrial dysfunction affect other brain regions, including the reticular formation, hippocampus, and prefrontal cortex. It is proposed that metal dyshomeostasis in combination with mitochondrial dysfunction could be the underlying mechanism responsible for the initiation and progression of the pathological changes associated with both the motor and extra-motor symptoms of ALS.

Vertebrate Sensory Ganglia: Common and Divergent Features of the Transcriptional Programs Generating Their Functional Specialization

Sensory fibers of the peripheral nervous system carry sensation from specific sense structures or use different tissues and organs as receptive fields, and convey this information to the central nervous system. In the head of vertebrates, each cranial sensory ganglia and associated nerves perform specific functions. Sensory ganglia are composed of different types of specialized neurons in which two broad categories can be distinguished, somatosensory neurons relaying all sensations that are felt and visceral sensory neurons sensing the internal milieu and controlling body homeostasis. While in the trunk somatosensory neurons composing the dorsal root ganglia are derived exclusively from neural crest cells, somato- and visceral sensory neurons of cranial sensory ganglia have a dual origin, with contributions from both neural crest and placodes. As most studies on sensory neurogenesis have focused on dorsal root ganglia, our understanding of the molecular mechanisms underlying the embryonic development of the different cranial sensory ganglia remains today rudimentary. However, using single-cell RNA sequencing, recent studies have made significant advances in the characterization of the neuronal diversity of most sensory ganglia. Here we summarize the general anatomy, function and neuronal diversity of cranial sensory ganglia. We then provide an overview of our current knowledge of the transcriptional networks controlling neurogenesis and neuronal diversification in the developing sensory system, focusing on cranial sensory ganglia, highlighting specific aspects of their development and comparing it to that of trunk sensory ganglia.

The Five Diaphragms in Osteopathic Manipulative Medicine: Neurological Relationships, Part 1

In osteopathic manual medicine (OMM), there are several approaches for patient assessment and treatment. One of these is the five diaphragm model (tentorium cerebelli, tongue, thoracic outlet, diaphragm, and pelvic floor), whose foundations are part of another historical model: respiratory-circulatory. The myofascial continuity, anterior and posterior, supports the notion the human body cannot be divided into segments but is a continuum of matter, fluids, and emotions. In this first part, the neurological relationships of the tentorium cerebelli and the lingual muscle complex will be highlighted, underlining the complex interactions and anastomoses, through the most current scientific data and an accurate review of the topic. In the second part, I will describe the neurological relationships of the thoracic outlet, the respiratory diaphragm and the pelvic floor, with clinical reflections. In literature, to my knowledge, it is the first time that the different neurological relationships of these anatomical segments have been discussed, highlighting the constant neurological continuity of the five diaphragms.

Prevalence and significance of cranial nerve imaging abnormalities in patients with hereditary neuropathies: Clinical implications at the skull base

OBJECTIVE

To estimate the prevalence and significance of cranial nerve (CN) imaging abnormalities in patients with hereditary neuropathy and discuss clinical implications.

METHODS

We retrospectively analyzed data from patients at four tertiary academic medical centers with hereditary neuropathy diagnoses who had undergone gadolinium-enhanced magnetic resonance imaging (MRI) of the brain or skull base between 2004 and 2018. MRI scans, as well as computed tomography imaging when available, were reviewed and bivariable analysis was performed to identify predictors of CN abnormalities on imaging.

RESULTS

Among 39 patients meeting study criteria, 11 had clinical CN deficits (28%) and 8 had CN abnormalities on imaging (21%). Of the patients with CN abnormalities on imaging, half had CN deficits (4/8) and only a quarter had imaging abnormalities of the CNs with the deficits (2/8). Imaging abnormalities were found in varied CNs, including CNs III, V, VII, and the VII/VIII complex in the internal auditory canal. MRI obtained for the purpose of evaluating CN deficits had a statistically significant increased likelihood of containing CN imaging abnormalities. However, CN deficits themselves were not predictive of imaging abnormalities.

CONCLUSION

Thickening and enhancement of CNs on MRI may be found in approximately 1/5 of patients with hereditary neuropathies and are inconsistently associated with clinical deficits. These imaging findings should not be mistaken for neoplastic and infectious processes as they may be manifestations of the patients' underlying genetic neuropathy.

LEVEL OF EVIDENCE

4.