The clinical significance of findings obtained on 3D-FLAIR MR imaging in patients with Ramsay-Hunt syndrome

Imaging Anatomy and Pathology of the Intracranial and Intratemporal Facial Nerve

The facial nerve is one of the most complex cranial nerves, with motor, sensory, and parasympathetic fibers. A large spectrum of congenital, inflammatory, vascular, and neoplastic processes may affect one or more segments of the nerve. Customized use of computed tomography and magnetic resonance imaging combined with good understanding of the nerve anatomy and relevant clinical/surgical key points is crucial for appropriate assessment of facial neuropathy. This article reviews the anatomy of the intracranial and intratemporal facial nerve, and the imaging features of the most frequent disorders involving those segments of the nerve.

CS-VIBE accelerates cranial nerve MR imaging for the diagnosis of facial neuritis: comparison of the diagnostic performance of post-contrast MPRAGE and CS-VIBE

OBJECTIVE

We aimed to compare the diagnostic performance of post-contrast 3D compressed sensing volume-interpolated breath-hold examination (CS-VIBE) and 3D T1 magnetization-prepared rapid-acquisition gradient-echo (MPRAGE) in detecting facial neuritis.

MATERIALS AND METHODS

Between February 2019 and September 2019, 60 patients (30 facial palsy patients and 30 controls) who underwent contrast-enhanced cranial nerve MRI with both conventional MPRAGE and CS-VIBE (scan time: 6 min 8 s vs. 2 min 48 s) were included in this retrospective study. All images were independently reviewed by three radiologists for the presence of facial neuritis. In patients with facial palsy, signal-to-noise ratio (SNR) of the pons, enhancement degree and contrast-to-noise ratio (CNR_nerve-CSF) of the facial nerve were measured. The overall image quality, artifacts, and facial nerve discrimination were analyzed. The sensitivity and specificity of both sequences were calculated with the clinical diagnosis as a reference.

RESULTS

CS-VIBE had comparable performance in the detection of facial neuritis to that of MPRAGE (sensitivity and specificity, 97.8% and 99.4% vs. 100.0% and 99.4% in pooled analysis; 97.8% and 98.9% vs. 100.0% and 98.9% in patents with facial palsy, p value > 0.05 for all). CS-VIBE showed significantly lower SNR (p value < 0.001 for all), but significantly higher CNR_nerve-CSF (p value < 0.05 for all) than MPRAGE. CS-VIBE also performed better in the overall image quality, artifacts, and facial nerve discrimination than MPRAGE (p value < 0.001 for all).

CONCLUSION

CS-VIBE achieved comparable diagnostic performance for facial neuritis compared to the conventional MPRAGE, with the scan time being half of that of MPRAGE.

KEY POINTS

• Post-contrast 3D CS-VIBE MRI is a reliable method for the diagnosis of facial neuritis. • CS-VIBE reduces the scan time of cranial nerve MRI by more than half compared to conventional T1-weighted image. • CS-VIBE had better performance in contrast-to-noise ratio and favorable image quality compared with conventional T1-weighted image.

High-resolution MR imaging of cranial neuropathy in patients with anti-GQ1b antibody syndrome

OBJECTIVE

The value of conventional MRI in patients anti-GQ1b antibody syndrome is subject to debate. Our purpose was to evaluate the diagnostic accuracy of high-resolution MRI for detecting cranial nerve abnormalities in patients with anti-GQ1b antibody syndrome.

MATERIALS AND METHODS

This retrospective cohort study enrolled 15 anti-GQ1b-positive patients diagnosed with MFS and related disorders and 17 age-matched controls, all of whom underwent high-resolution MR imaging including pre-contrast and contrast-enhanced (CE) 3D FLAIR and 3D CE T1-weighted turbo field echo (T1-TFE) between 2010 and 2016. The diagnostic performance of high-resolution MRI was assessed using the area under the curve (AUC) of the receiver operating characteristics curve. Inter- and intraobserver agreements were calculated using kappa statistics and intraclass correlation coefficients (ICC), respectively.

RESULTS

Ophthalmoplegia, ataxia, and hypo/areflexia were present in 100%, 60%, and 67%, respectively. Other neurologic findings included ptosis (40%), mydriasis (13%), and facial (27%) and bulbar (13%) palsy. Fourteen of sixteen (88%) MR examinations in 15 patients demonstrated at least one cranial nerve abnormality corresponding to the clinical findings. The involved cranial nerves on MRI were the IIIrd cranial nerve in 14 patients, VIth in nine, VIIth in four, Vth in one, and VIIIth in one. AUC values for detecting cranial neuropathy on high-resolution MRI were 0.938 (95% CI: 0.795-0.992) on a per patient basis. Inter- and intraobserver agreements were 0.842 and 0.945, respectively.

CONCLUSION

High-resolution 3D FLAIR and CE 3D T1-TFE MRI has high reliability and accuracy for demonstrating cranial neuropathy in patients with anti-GQ1b antibody syndrome.

Mastoid effusion on temporal bone MRI in patients with Bell's palsy and Ramsay Hunt syndrome

This study aimed to investigate the incidence of mastoid effusion on temporal bone magnetic resonance imaging (MRI) in patients with Bell’s palsy (BP) and Ramsay Hunt syndrome (RHS), and evaluate the usefulness of mastoid effusion in early differential diagnosis between BP and RHS. The incidence of mastoid effusion on 3.0 T—temporal bone MRI, which was conducted within 10 days after the onset of acute facial nerve palsy, was compared between 131 patients with BP and 33 patients with RHS. Findings of mastoid cavity on temporal bone MRI were classified into three groups as normal mastoid, mastoid effusion, and sclerotic change, and the incidence of ipsilesional mastoid effusion was significantly higher in RHS than BP (P < 0.001). Tympanic membrane was normal in 7 of 14 RHS patients with mastoid effusion, and injected without middle ear effusion in 7 patients. This study highlights significantly higher incidence of ipsilesional mastoid effusion in RHS than BP, and suggests that the presence of mastoid effusion may provide additional information for differential diagnosis between RHS and BP.

Signal intensity pattern of the normal oculomotor nerve on contrast-enhanced 3D FLAIR at 3.0 T MRI

PURPOSE

The aim of this study was to depict the signal intensity pattern of the normal oculomotor nerve demonstrated on contrast-enhanced three-dimensional fluid-attenuated inversion recovery images.

MATERIALS AND METHODS

Eighty-one patients were included in the study. Contrast-enhanced three-dimensional fluid-attenuated inversion recovery images with magnetisation-prepared rapid acquisition were reconstructed and evaluated in the coronal plane. The signal intensity of the cisternal segment of the oculomotor nerve was graded into a visual scale of 1 to 5 as compared to the white matter, grey matter and the pituitary stalk. The signal intensity ratio of the oculomotor nerve was consequently measured.

RESULTS

By using the visual scale, more than half of the oculomotor nerves showed higher signal intensity than the grey matter signal on contrast-enhanced three-dimensional fluid-attenuated inversion recovery images (59.3-80.2%). It can demonstrate a signal intensity similar to the pituitary stalk (14.8%) by visualisation. None of them showed signal intensity equal to the normal white matter signal. By signal intensity measurement, the mean signal intensity ratio of oculomotor nerves to white matter equals 1.54±0.20 (95% confidence interval (CI) 1.51-1.57); mean signal intensity ratio to grey matter equals 1.16±0.15 (95% CI 1.14-1.18); mean signal intensity ratio to the pituitary stalk equals 0.68±0.10 (95% CI 0.64-0.70).

CONCLUSIONS

The normal oculomotor nerve visualised on contrast-enhanced three-dimensional fluid-attenuated inversion recovery images has a higher signal intensity than the white matter and may have a signal intensity similar to the grey matter or the pituitary stalk. The high signal intensity of the oculomotor nerve in contrast-enhanced three-dimensional fluid-attenuated inversion recovery should not be misinterpreted as a pathology.

Imaging of facial neuritis using T2-weighted gradient-echo fast imaging employing steady-state acquisition after gadolinium injection

BACKGROUND

MRI is the modality of choice for the imaging of facial neuritis. Previously, gadolinium-enhanced T1-weighted imaging of the petrous bone, then FLAIR sequences were thought to be most informative for acute facial neuritis imaging. The aim of this study is to evaluate the value of contrast-enhanced T2-weighted sequence for the diagnosis of acute facial neuritis and compare it to contrast-enhanced T1-weighted and FLAIR sequences.

METHODS

We included 50 patients with an acute unilateral idiopathic peripheral facial neuritis. An MRI (3 T) with three sequences was performed (T1-weighted, T2-weighted and FLAIR), all acquired after intravenous contrast-media injection.

RESULTS

The contrast-enhanced T2-weighted sequence appeared to be the most accurate one for the diagnosis of acute facial neuritis (Se 94%, Sp 100%, accuracy 98.2%, p < 0.001), with a pathological facial nerve strongly (grade 2-3) enhancing and a homogenous enhancement along the course of the entire facial nerve. Contrast-enhanced T1-weighted (Se 80%, Sp 100%, accuracy 94.1%) and FLAIR sequences (92%, Sp 88%, accuracy 90%, p < 0.001) showed lower accuracy. On T1-weighted sequence, a strong enhancement (blurred margins) of the canalicular segment was observed in 80% of the cases when it was never observed in normal nerves.

CONCLUSION

A strong (= iso to hyperintense to the petrous fat signal) and diffuse (all segments) enhancement of the facial nerve on T2-weighted steady-state free precession sequence is a sensitive and specific sign for the diagnosis of acute idiopathic facial neuritis, and appears superior to T1WI and FLAIR sequences.

Atypical clinical manifestations of herpes zoster oticus: diagnostic usefulness of magnetic resonance imaging

Typical symptoms of Ramsay Hunt syndrome (RHS) consist of painful vesicular eruptions in the external ear, unilateral facial palsy, and/or vestibulocochlear deficit. When RHS patients show atypical clinical manifestations, correct diagnosis can be delayed, and ideal treatment timing for antiviral therapy may be missed. The aim of this study is to describe RHS patients with atypical clinical manifestations and evaluate the usefulness of magnetic resonance imaging (MRI) for early differential diagnosis. We retrospectively reviewed the clinical data and investigated the findings of internal auditory canal (IAC) MRI of seven patients diagnosed with RHS presenting "atypical" clinical manifestations between January 2013 and December 2016. "Typical" symptoms of RHS consist of herpetic vesicular eruption and facial palsy with or without vestibulocochlear deficit. Regardless of symptomatic presentations, IAC MRI demonstrated post-contrast enhancement of cranial nerve (CN) VII, CN VIII, and IAC dura in patients with atypical clinical manifestations. In cases with multiple lower CN palsy, enhancement along the involved nerve was observed on IAC MRI. When RHS was complicated by acute parotiditis, diffuse enhancement of the parotid gland was demonstrated. The present study shows that in IAC MRI of RHS patients with atypical clinical manifestations, post-contrast enhancement was not confined to the facial nerve but also observed in CN VIII and IAC dura regardless of the symptoms, which may facilitate early diagnosis of RHS.

Clinical Characteristics of Dizziness Associated with Acute Peripheral Facial Palsy

Background and Objectives

We aimed to assess the clinical significance of dizziness associated with acute peripheral facial palsy (APFP).

Subjects and Methods

Medical records of patients who visited an otorhinolaryngology clinic at a university hospital and were admitted for treatment of APFP between 2014 and 2016 were thoroughly reviewed.

Results

In total, 15.3% (n=15) of patients had dizziness. Continuous, rotatory dizziness without exacerbating factors was most common and frequently accompanied by nausea/vomiting. Dizziness disappeared within 1 week during the hospitalization period. Patients with Ramsay Hunt syndrome (31.0%) had dizziness more frequently than those with Bell’s palsy (8.7%). In addition, higher hearing thresholds and pain around the ear was reported more often in dizzy patients (p<0.05). Logistic regression analysis revealed that the initial House-Brackmann grade of facial paralysis was solely associated with final recovery, but dizziness was not associated with prognosis.

Conclusions

Patients with APFP may have transient dizziness in the early stage, which may be more frequently accompanied by worse hearing thresholds and/or pain around the ear. However, these symptoms including dizziness seem to be unrelated to final prognosis.

Quantifying Pediatric Facial Palsy: : Using Digital Image Correlation to Objectively Characterize Pediatric Facial Symmetry

OBJECTIVE

This study introduces digital image correlation (DIC) as a novel technology to objectively quantify pediatric facial symmetry.

DESIGN

Descriptive cohort study of patients' facial symmetry as measured by DIC.

SETTING

Academic tertiary care hospital.

PATIENTS

9 of 12 identified facial palsy and 13 of 26 identified control subjects participated.

INTERVENTIONS

DIC was used to quantify facial strain and symmetry as patients made the 5 standard Sunnybrook facial expressions. Each subject was evaluated according to the Sunnybrook scale by 4 evaluators, 3 plastic surgeons, and 1 occupational therapist.

MAIN OUTCOME MEASURE

The percentage asymmetry values were calculated and compared between the facial palsy and control groups using both DIC and Sunnybrook.

RESULTS

Using DIC, facial palsy subjects had 32.99% asymmetry compared with 14.84% in controls (P < .01). Using Sunnybrook, facial palsy subjects had 24.11% asymmetry compared to 3.87% in controls (P < .01). The 2 metrics were positively correlated (P < .01). There was significant variability among the Sunnybrook evaluators (P = .02).

CONCLUSIONS

DIC is a novel technique of objectively quantifying facial motion of the animated face. As surgical and medical approaches toward facial palsy expand, it is essential to have a means to compare results and improve patient outcomes.

Cranial Nerve Disorders in Children: MR Imaging Findings

Cranial nerve disorders are uncommon disease conditions encountered in pediatric patients, and can be categorized as congenital, inflammatory, traumatic, or tumorous conditions that involve the cranial nerve itself or propagation of the disorder from adjacent organs. However, determination of the normal course, as well as abnormalities, of cranial nerves in pediatric patients is challenging because of the small caliber of the cranial nerve, as well as the small intracranial and skull base structures. With the help of recently developed magnetic resonance (MR) imaging techniques that provide higher spatial resolution and fast imaging techniques including three-dimensional MR images with or without the use of gadolinium contrast agent, radiologists can more easily diagnose disease conditions that involve the small cranial nerves, such as the oculomotor, abducens, facial, and hypoglossal nerves, as well as normal radiologic anatomy, even in very young children. If cranial nerve involvement is suspected, careful evaluation of the cranial nerves should include specific MR imaging protocols. Localization is an important consideration in cranial nerve imaging, and should cover entire pathways and target organs as much as possible. Therefore, radiologists should be familiar not only with the various diseases that cause cranial nerve dysfunction, and the entire course of each cranial nerve including the intra-axial nuclei and fibers, but also the technical considerations for optimal imaging of pediatric cranial nerves. In this article, we briefly review normal cranial nerve anatomy and imaging findings of various pediatric cranial nerve dysfunctions, as well as the technical considerations of pediatric cranial nerve imaging. Online supplemental material is available for this article. (©)RSNA, 2016.

Cerebrospinal fluid viral load and biomarkers of neuronal and glial cells in Ramsay Hunt syndrome

Reactivation of varicella zoster virus (VZV) can manifest with facial palsy diagnosed as Ramsay Hunt Syndrome (RHS) or Ramsay Hunt Syndrome zoster sine herpete (RHS-ZSH). These syndromes are associated with poor prognosis despite treatment with antivirals and corticosteroids. Concentrations of biomarkers such as neurofilament protein (NFL), S-100β protein and glial fibrillary acidic protein (GFAp) have previously been measured in cerebrospinal fluid (CSF) to assess neuronal damage and glial pathology. We employed immunochemical methods to measure concentrations of NFL, S-100β protein and GFAp in CSF from patients with RHS (n = 15) and RHS-ZSH (n = 13) diagnosed by detection of VZV DNA in the CSF by quantitative PCR, and compared with a control group (n = 52). The biomarker concentrations were correlated with CSF viral load and outcome measured by House-Brackmann score. NFL and GFAp concentrations were increased compared with controls (P = 0.008 and P = 0.04), while S-100β levels were decreased. This pattern was more pronounced in patients with RHS compared to the patients with RHS-ZSH (NS and P = 0.028). The amount of viral DNA in CSF correlated with increased GFAp (P = 0.003) and NFL (P = 0.006). No correlations were found between biomarker concentrations and patient outcome. Patients with facial palsy caused by VZV had biochemical signs of neuronal damage and astrogliosis. High amounts of viral DNA may be associated with the degree of damage on neuronal and astroglial cells. Prospective studies are warranted to elucidate the association of elevated biomarkers in the CSF and outcome assessed by more sensitive tests.

The Technical and Clinical Features of 3D-FLAIR in Neuroimaging

In clinical MR neuroimaging, 3D fluid-attenuated inversion recovery (3D-FLAIR) with a variable-flip-angle turbo spin echo sequence is becoming popular. There are more than 100 reports regarding 3D-FLAIR in the PubMed database. In this article, the technical and clinical features of 3D-FLAIR for neuroimaging are reviewed and summarized. 3D-FLAIR allows thinner slices with multi-planar reformation capability, a higher flow sensitivity, high sensitivity to subtle T1 changes in fluid, images without cerebrospinal fluid (CSF) inflow artifacts, and a 3D dataset compatible with computer-aided analysis. In addition, 3D-FLAIR can be obtained within a clinically reasonable scan time. It is important for radiologists to be familiar with the features of 3D-FLAIR and to provide useful information for patients.