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.

Internal Carotid Artery Aneurysm Presenting as Lower Cranial Nerve Palsies.

The signs of lower cranial nerve palsies are rare and are often caused by tumors. A 49-year-old woman was admitted to our hospital with progressive right-sided atrophy of the tongue, sternocleidomastoid and trapezius, dysarthria, and dysphagia for 3 years. Brain magnetic resonance imaging revealed a circular lesion adjacent to the lower cranial nerves. Cerebral angiography confirmed that the lesion was an unruptured aneurysm in the C1 segment of the right internal carotid artery. After endovascular treatment, the symptoms of this patient had partially improved.

ACR Appropriateness Criteria® Cranial Neuropathy: 2022 Update.

Cranial neuropathy can result from pathology affecting the nerve fibers at any point and requires imaging of the entire course of the nerve from its nucleus to the end organ in order to identify a cause. MRI with and without intravenous contrast is often the modality of choice with CT playing a complementary role. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Imaging of Cranial Neuralgias.

Cranial neuralgia (CN) can cause significant debilitating pain within a nerve dermatome. Accurate diagnosis requires detailed clinical history and examination, understanding of pathophysiology and appropriate neuroimaging to develop an optimal treatment plan. The objective of this article is to review and discuss some of the more common CNs including trigeminal neuralgia and its associated painful neuropathies, occipital neuralgia, and less common glossopharyngeal neuralgia (GPN). The neuroanatomy, pathophysiology, diagnostic imaging, and treatment of each of these pathologies are reviewed with emphasis on the role of CT and MR imaging findings in guiding diagnosis. Although CT is often used to initially identify an underlying cause such as neoplasm, infection, or vascular malformation, MRI is optimal. Clinical history and examination findings along with MRI constructive interference steady state/fast imaging employing steady-state acquisition sequences and MRA of the brain can be used to distinguish between primary and secondary cranial neuropathies and to discern the best treatment option. Pharmacologic and noninvasive therapy is the first-line of treatment of these cranial and cervical neuralgias. If symptoms persist, stereotactic radiosurgery is an option for some patients, although microvascular decompression surgery is the most curative option for both trigeminal and GPN. Refractory occipital neuralgia can be treated with a nerve block, an ablative procedure such as neurectomy or ganglionectomy, or more recently occipital nerve stimulation.

MRI Results of Patients with Acute Isolyted Cranial Nerve Palsies.

AIM: To investigate the magnetic resonance imaging (MRI) results of patients complaining from diplopia with ocular nerve palsy. MATERIAL AND METHODS: A routine ophthalmic examination was performed, a neurological consultation was requested, and cranial MRI was performed for all patients. The image results were sorted into four groups: ischemic lesions, demyelinating disease lesions, tumors, and no lesions. White matter gliosis and cerebral infarcts were included in the ischemic lesion group. The medical histories of the patients were acquired from medical records. The chi-squared test was used to analyze the relationship between age and cranial MRI images and to analyze the relationship between the image and paresis type. The statistical significance threshold was set at p < 0.05, unless otherwise stated. RESULTS: Ischemic MRI images were the most common image type seen in our study. Third nerve paresis was significantly correlated with ischemic cerebral lesions observed by MRI (p=0.009). Furthermore, lesions were significantly correlated with patients aged above 50 years (p=0.004). There were no significant correlations between fourth or sixth nerve paresis and cranial ischemic images (p=0.680 and p=0.678, respectively). There were two instances of cerebral artery aneurysm, three instances of cerebral infarct, and one instance of intracranial mass, all in patients aged over 50 years. CONCLUSION: Although our patients had minimal or nonexistent neurological symptoms, some had serious cranial pathologies. These pathologies were commonly seen in patients aged over 50 years. We recommend performing MRI on all patients with binocular diplopia.

Newly occurring cranial nerve palsy after endovascular treatment of cavernous sinus dural arteriovenous fistulas.

OBJECTIVE: Cranial nerve palsy (CNP) is rarely reported after endovascular intervention for cavernous sinus dural arteriovenous fistulas (CS DAVFs). Our aim was to evaluate the treatment outcomes of CS DAVFs, and the clinical course and risk factors of newly occurring CNPs, with a review of the literature. METHODS: 121 patients with 134 lesions treated in our institution were selected. They were retrospectively analyzed in terms of baseline characteristics, radiologic results, clinical outcome, and newly occurring CNPs after treatment. Angiographic and clinical follow-up data were available for 104 lesions (77.6%) and 130 lesions (97.0%), respectively. RESULTS: The angiographic results showed partial:complete obliterations in 13:91 (87.5%) at the final follow-up. Clinical outcomes were deteriorated or no change:improved or completely recovered (3:126 (96.9%)) at the final follow-up. New CNPs occurred in 24 patients (19.8%), including the sixth CNP alone or mixed in 23 patients (95.8%). 23 cases were completely recovered or improved (21 and 2 cases, respectively), and 19 (90.4%) of 21 were completely recovered within 6 months after treatment. In the multivariate analysis, pretreatment cranial nerve symptoms (OR=0.33; 95% CI 0.14 to 0.76; P=0.010) and complete obliteration immediately after treatment (OR=0.32; 95% CI 0.12 to 0.85; P=0.021) were significant preventive factors for new CNPs. Embolization in the posterior compartments of the CS (OR=5.15; 95% CI 1.71 to 15.47; P=0.004) was a significant risk factor. CONCLUSIONS: Endovascular intervention was satisfactory in patients with CS DAVFs. The prognosis of newly occurring CNPs was favorable.

[Atypical skull base osteomyelitis suspected of spreading inflammation from the ear canal with unilateral multiple cranial neuropathy and cerebral infarctions].

A 76-year-old man, who had undergone surgery for esophageal cancer in 2010, presented to our hospital in April 2017 complaining of prolonged slight fever, loss of appetite, and dysphagia. Initial evaluation revealed a paralyzed left vocal cord, slight muscle weakness of the extremities, left facial paralysis, hoarseness, left sternocleidomastoid and trapezius muscle weakness, tongue deviation to the left, and left hypacusia-suggesting a diagnosis of Garcin's syndrome. Laboratory tests revealed increased white blood cells and C-reactive protein. Cerebrospinal fluid (CSF) analysis showed mild pleocytosis (predominantly polymorphonuclear cells), elevated protein, and low CSF/plasma glucose ratio. CT showed mild clival erosion, with no evidence of carcinoma recurrence. Brain contrast-enhanced MRI showed abnormal clival marrow, enhanced soft tissue and dura matter from the clivus to the atlantoaxial joint, enhanced soft tissue around the left ear canal, multiple cerebral infarctions in the left watershed zones, and left internal carotid stenosis. There was excessive ear wax and inflammation of the left external acoustic meatus but no otorrhea or otalgia. On the basis of his overall presentation, he was diagnosed with atypical skull base osteomyelitis due to external otitis. He was treated with antibiotic treatment that included ceftazidime for the Pseudomonas aeruginosa detected on bacterial cultures. He did not respond to treatment and died approximately 4 months later. Skull base osteomyelitis is thus an important differential diagnosis candidate after finding unilateral, multiple cranial neuropathy, underscoring the importance of prompt treatment when suspected.

Dorsally exophytic glioblastoma of the pons.

Brainstem gliomas are rare tumours in adults, accounting for only 1%-2% of all intracranial gliomas. They are recognised as a heterogeneous group, in which most are malignant tumours. Brainstem gliomas are classified into four major groups according to the growth pattern on imaging, namely diffuse, focal, exophytic and cervicomedullary. Such a classification system is also useful for surgical decision making. The exophytic variant is extremely rare having anecdoctal reports in the literature. We report the case of an adult patient affected by an exophytic glioblastoma of the pons, which was submitted to subtotal resection followed by radiation therapy and chemotherapy with a longer overall survival. To the best of our knowledge, this is the seventh adult patient reported of an exophytic brainstem glioblastoma.

Relationship of clinical presentation and angiographic findings in patients with indirect cavernous carotid fistulae.

INTRODUCTION: Indirect cavernous carotid fistulae (ICCFs) can present with insidious, non-specific symptoms and prove difficult to diagnose. This study evaluates associations among ICCF symptoms and angiographic findings. METHODS: A retrospective analysis was performed of prospectively maintained records at four medical centers to identify patients with ICCFs evaluated with angiography. Patient demographics, symptoms, and angiographic findings were tabulated. Univariate and multivariate analyses were conducted to identify associations among these variables. RESULTS: Records sufficient for review existed for 267 patients evaluated with angiography. Patients were most commonly women, in the sixth or seventh decade of life, and had symptoms for months before a definitive diagnosis. The most common symptoms included proptosis, diplopia, cranial nerve palsy, and chemosis. Cortical venous reflux was most common in patients with chemosis, orbital pain, or bruit. Intracranial hemorrhage was associated with cortical reflux and bilateral inferior petrosal sinus occlusion. Patients with loss of symptoms demonstrated higher rates of inferior petrosal sinus occlusion and a trend towards rupture. CONCLUSION: A high index of suspicion is needed to promptly diagnose patients with ICCFs. High risk features are more common in the setting of chemosis, orbital pain, bruit, or spontaneous loss of symptoms. Patients with such symptoms warrant expedited angiographic evaluation.

MRI Tractography Detecting Cranial Nerve Displacement in a Cystic Skull Base Tumor.

A 37-year-old man came to our neurosurgical department with a 2-month history of a progressive invalidating balance disorder. Cerebral magnetic resonance imaging found a T2-weighted hypersignal lesion of the right cerebellopontine angle that severely compressed the brainstem, however the position of cranial nerves was not clearly identified. The new MRI diffusion tool, tractography, allowed to reconstruct the trajectory of cranial nerves that were displaced by the tumor. As such, the acoustic facial bundle was severely flattened posteriorly and superiorly, while the lower nerves were pushed inferiorly. Effective neurosurgical decompression was performed and confirmed the position of cranial nerves V-XII. The patient was discharged and returned home without any cranial nerve deficit. This case illustrates how advances in imaging can now better describe the anatomy surrounding brain tumors and make surgery safer to the benefit of patients.

Vernet syndrome resulting from varicella zoster virus infection-a very rare clinical presentation of a common viral infection.

Vernet syndrome is a unilateral palsy of glossopharyngeal, vagus, and accessory nerves. Varicella zoster virus (VZV) infection has rarely been described as a possible cause. A 76-year-old man presented with 1-week-long symptoms of dysphonia, dysphagia, and weakness of the right shoulder elevation, accompanied by a mild right temporal parietal headache with radiation to the ipsilateral ear. Physical examination showed signs compatible with a right XI, X, and XI cranial nerves involvement and also several vesicular lesions in the right ear's concha. He had a personal history of poliomyelitis and chickenpox. Laringoscopy demonstrated right vocal cord palsy. Brain MRI showed thickening and enhancement of right lower cranial nerves and an enhancing nodular lesion in the ipsilateral jugular foramen, in T1 weighted images with gadolinium. Cerebrospinal fluid (CSF) analysis disclosed a mild lymphocytic pleocytosis and absence of VZV-DNA by PCR analysis. Serum VZV IgM and IgG antibodies were positive. The patient had a noticeable clinical improvement after initiation of acyclovir and prednisolone therapy. The presentation of a VZV infection with isolated IX, X, and XI cranial nerves palsy is extremely rare. In our case, the diagnosis of Vernet syndrome as a result of VZV infection was made essentially from clinical findings and supported by analytical and imaging data.

Collet-Sicard Syndrome Attributable to Extramedullary Plasmacytoma of the Jugular Foramen.

BACKGROUND: Collet-Sicard syndrome is a rare manifestation of skull base disease involving the jugular and hypoglossal foramina. We report the first case of Collet-Sicard attributable to extramedullary plasmacytoma-multiple myeloma (EP-MM) and the second case of EP-MM precipitating a jugular foramen syndrome (JFS)-spectrum disorder. CASE DESCRIPTION: A 59-year-old woman presented with 4 months of left aural fullness and pulsatile tenderness, positional vertigo, hoarseness, and dysphagia. Examination identified left tongue weakness and nonspecific sensory abnormalities of the ear, pharynx, and throat localizing to cranial nerves IX-XII. Imaging revealed a 3.4 × 1.4 × 2.8 cm lytic lesion extending from the left jugular foramen into the posterior fossa, for which she was referred to neurosurgery and otolaryngology for consideration of resection. A second, much smaller (1.1-cm) lytic lesion in the left posterior occipital bone was incidentally discovered by the surgeon during preoperative consultation. A stereotactic biopsy of the occipital lesion was subsequently recommended, which identified plasma cell neoplasm. Serum studies and skeletal survey were consistent with MM, and a definitive pathologic diagnosis of MM with cranial EP was confirmed by bone marrow biopsy. CONCLUSION: Tumors of the jugular foramen present with a diverse array of lower cranial nerve deficits, including Collet-Sicard syndrome, a rare subset of JFS-spectrum diseases. Paragangliomas are the most common jugular foramen neoplasms, followed by schwannomas and meningiomas; however, many other rare entities have been reported as masqueraders, and diligent work-up with consideration for preliminary biopsy is recommended, particularly in the presence of additional lesions, equivocal imaging findings, or cases arousing high suspicion.