The clinical availability of facial nerve enhancement in temporal bone MRI for the patients of idiopathic acute peripheral facial palsy.

PURPOSE: This study is to evaluate the duration of facial nerve enhancement in gadolinium-enhanced temporal bone MRI after the onset of acute facial palsy. METHODS: Gd-enhanced MRI imagines were examined in 13 patients with idiopathic acute facial palsy within 14 days after the onset. The degree of facial nerve function was measured according to the House-Brackmann (H-B) grading system at their first visit at outpatient clinic. The follow-up MRI was taken about 16.5 months (7-24 months) after onset of disease. The degree of facial nerve enhancement was measured with signal intensity (SI) which was quantitatively analyzed using the region-of-interest (ROI) measurements for each segment of the facial nerve. SI was statistically analyzed by comparing SI values of contralateral site and ipsilateral site using the paired t test with SPSS program. RESULTS: The gadolinium enhancement was statistically increased at labyrinthine segment and geniculate ganglion area of facial nerve at initial temporal bone MRI. The gadolinium enhancement was statistically decreased at all the segments of facial nerve except tympanic segment (p < 0.05) at follow-up MRI. CONCLUSIONS: The facial nerve enhancement in Gd-enhanced MRI images prolonged more than 21 months of the onset. The newly developed pathologic lesions of acute facial palsy especially occur at the site of labyrinthine and geniculate ganglion.

Predicting value for incomplete recovery in Bell's palsy of facial nerve ultrasound versus nerve conduction study.

OBJECTIVE: This longitudinal study aims at assessing the predictive value of facial nerve high-resolution ultrasound (HRUS) for incomplete clinical recovery in patients with Bell's palsy, the most common facial nerve disease. METHODS: We prospectively enrolled 34 consecutive patients with Bell's palsy. All patients underwent neurophysiological testing (including facial nerve conduction study) and HRUS evaluations 10-15 days (T1), one month (T2), and three months (T3) after the onset of Bell's palsy. Patients who did not experience complete recovery within three months were also evaluated after six months (T4). We have then compared the accuracy of HRUS with that of the facial nerve conduction study in predicting incomplete clinical recovery at three and six months. RESULTS: At T1, the facial nerve diameter, as assessed with HRUS, was larger on the affected side than on the normal side, particularly in patients with incomplete recovery at T2, T3 and T4. ROC curve analysis, however, showed that the facial nerve diameter at T1 had a lower predictive value than the facial nerve conduction study for an incomplete clinical recovery at three (T3) and six (T4) months. Still, the facial nerve diameter asymmetry, as assessed with HRUS, had a relatively high negative predictive value (thus indicating a strong association between normal HRUS examination and a good prognosis). CONCLUSIONS: Although HRUS shows abnormally increased facial nerve diameter in patients in the acute phase of Bell's palsy, the predictive value of this technique for incomplete clinical recovery at three and six months is lower than that of the nerve conduction study. SIGNIFICANCE: Nerve ultrasound has a low predictive value for incomplete clinical recovery in patients with Bell's Palsy.

Contrast-enhanced MRI findings of patients with acute Bell palsy within 7 days of symptom onset: A retrospective study.

The brain magnetic resonance imaging (MRI) findings seen in patients with Bell palsy are abnormal contrast enhancement of affected facial nerves. Previous studies were conducted on a few patients, mainly those who had experienced palsy for several weeks. This study investigated the diagnostic usefulness of MRI by examining MRI findings of acute Bell palsy (within 7 days of symptom onset) in a large cohort. Among the patients with Bell palsy (idiopathic unilateral facial palsy) who visited the hospital, 123 patients who underwent contrast-enhanced MRI of the internal auditory canal within 7 days of symptom onset were reviewed retrospectively. MRI examination results were investigated along with the patient's clinical symptoms and electrodiagnostic test results. Based on the MRI results, the frequency of abnormal contrast enhancement and contrast-enhanced areas were investigated. Of the 123 patients, 13 (11%) had normal brain MRI results, and 110 (89%) had abnormal findings. The frequency of abnormal contrast enhancement was not significantly associated with test timing (P = .56). Of the 110 patients with abnormal findings, 65 (59%) showed contrast enhancement in the labyrinthine segment and 36 (33%) in both the labyrinthine segment and geniculate ganglion. Most patients with Bell palsy who are in the acute phase showed abnormal contrast enhancement in their facial nerves, and similar findings were even observed in the examination conducted on the day of symptom onset. Brain MRI helps in the diagnosis of acute Bell palsy.

To explore the pathogenesis of Bell's palsy using diffusion tensor image.

To explore the pathogenesis of Bell's palsy using the diffusion tensor image on 3.0 T MR. The healthy people and the patients with Bell's palsy underwent intraparotid facial nerve scanning by using the DTI and T1 structural sequence at 3.0 T MR. The raw DTI data were performed affine transformation and nonlinear registration in the common MNI152_T1 space and resampled to the 0.4 mm3 voxel size. A group of 4 spherical seed regions were placed on the intratemporal facial nerves in the common space, bilaterally and symmetrically. The DTI data in the common space were used to track the intratemporal facial nerve fibers by using TrackVis and its Diffusion Toolkit. Each tractography was used to construct the maximum probability map (MPM) according to the majority rule. The fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) were calculated and extracted on the basis of MPM. For healthy people, there was no significant difference in FA, MD, RD and AD of bilateral facial nerves. For patients with Bell's palsy, there was no significant difference in AD, there was significant difference in FA, MD and RD between the affected nerve and the healthy nerve (P < 0.02). This study showed that the myelin sheath injury of the intratemporal facial nerve is the main cause of Bell's palsy. Most neural axons are not damaged. The results may explain the pathogenesis of the Bell's palsy, which is self-limited for most cases.

Ventrolateral pontomedullary junction ischaemic stroke imitating isolated facial nerve palsy.

A 75-year-old woman presenting with unilateral lower motor neurone facial weakness was ultimately diagnosed with an ischaemic stroke at the pontomedullary junction affecting the facial nerve fascicles. Isolated, unilateral, upper and lower facial weakness is typically caused by lesions affecting the facial nerve, such as Bell's palsy, though rarely can be a manifestation of acute ischaemic stroke. It is important for neurologists and emergency providers to determine appropriately which patients with facial weakness require neuroimaging and which do not.

Incidence of Underlying Abnormal Findings on Routine Magnetic Resonance Imaging for Bell Palsy.

Importance: There is no consensus on the benefits of routine magnetic resonance imaging (MRI) of the facial nerve in patients with suspected idiopathic peripheral facial palsy (PFP) (ie, Bell palsy [BP]). Objectives: To estimate the proportion of adult patients in whom MRI led to correction of an initial clinical diagnosis of BP; to determine the proportion of patients with confirmed BP who had MRI evidence of facial nerve neuritis without secondary lesions; and to identify factors associated with secondary (nonidiopathic) PFP at initial presentation and 1 month later. Design, Setting, and Participants: This retrospective multicenter cohort study analyzed the clinical and radiological data of 120 patients initially diagnosed with suspected BP from January 1, 2018, to April 30, 2022, at the emergency department of 3 tertiary referral centers in France. Interventions: All patients screened for clinically suspected BP underwent an MRI of the entire facial nerve with a double-blind reading of all images. Main Outcomes and Measures: The proportion of patients in whom MRI led to a correction of the initial diagnosis of BP (any condition other than BP, including potentially life-threating conditions) and results of contrast enhancement of the facial nerve were described. Results: Among the 120 patients initially diagnosed with suspected BP, 64 (53.3%) were men, and the mean (SD) age was 51 (18) years. Magnetic resonance imaging of the facial nerve led to a correction of the diagnosis in 8 patients (6.7%); among them, potentially life-threatening conditions that required changes in treatment were identified in 3 (37.5%). The MRI confirmed the diagnosis of BP in 112 patients (93.3%), among whom 106 (94.6%) showed evidence of facial nerve neuritis on the affected side (hypersignal on gadolinium-enhanced T1-weighted images). This was the only objective sign confirming the idiopathic nature of PFP. Conclusions and Relevance: These preliminary results suggest the added value of the routine use of facial nerve MRI in suspected cases of BP. Multicentered international prospective studies should be organized to confirm these results.

Magnetic resonance imaging findings of delayed facial palsy after dental procedures suggest viral reactivation as pathogenesis: a retrospective study.

PURPOSE: We hypothesize that delayed facial paralysis following dental procedures is also associated with viral reactivation. In this study, the brain magnetic resonance imaging (MRI) findings of patients were analyzed to identify the pathogenesis of facial nerve palsy after dental treatment. MATERIALS AND METHODS: We retrospectively reviewed the medical records of patients with unilateral facial nerve palsy and identified those diagnosed with delayed facial nerve palsy within 30 days of dental treatment. We assessed the clinical characteristics, electrodiagnostic findings, and imaging findings of these patients and looked for MRI findings that support a viral hypothesis for facial palsy. RESULTS: Among 924 patients with facial palsy, 11 (1.2%) had delayed facial paralysis following dental procedures. Patients developed facial palsy at an average of 3.2 days (1-11 days) after undergoing a dental procedure. The internal auditory canal MRI revealed abnormal enhancement of affected facial nerve in nine patients. The intensity and pattern of the enhancement were similar to those of Bell's palsy. CONCLUSIONS: Facial palsy can develop within the days following dental procedures, and the MRI results suggest that delayed facial palsy after dental treatment is related to viral reactivation-like Bell's palsy.

Exploratory Study of the Brain Response in Facial Synkinesis after Bell Palsy with Systematic Review and Meta-analysis of the Literature.

BACKGROUND: Facial synkinesis, characterized by unintentional facial movements paired with intentional movements, is a debilitating sequela of Bell palsy. PURPOSE: Our aim was to determine whether persistent peripheral nerve changes arising from Bell palsy result in persistent altered brain function in motor pathways in synkinesis. DATA SOURCES: A literature search using terms related to facial paralysis, Bell palsy, synkinesis, and fMRI through May 2021 was conducted in MEDLINE and EMBASE. Additionally, an fMRI study examined lip and eyeblink movements in 2 groups: individuals who fully recovered following Bell palsy and individuals who developed synkinesis. STUDY SELECTION: Task-based data of the whole brain that required lip movements in healthy controls were extracted from 7 publications. Three studies contributed similar whole-brain analyses in acute Bell palsy. DATA ANALYSIS: The meta-analysis of fMRI in healthy control and Bell palsy groups determined common clusters of activation within each group using activation likelihood estimates. A separate fMRI study used multivariate general linear modeling to identify changes associated with synkinesis in smiling and blinking tasks. DATA SYNTHESIS: A region of the precentral gyrus contralateral to the paretic side of the face was hypoactive in synkinesis during lip movements compared with controls. This region was centered in a cluster of activation identified in the meta-analysis of the healthy controls but absent from individuals with Bell palsy. LIMITATIONS: The meta-analysis relied on a small set of studies. The small sample of subjects with synkinesis limited the power of the fMRI analysis. CONCLUSIONS: Premotor pathways show persistent functional changes in synkinesis first identifiable in acute Bell palsy.

The evaluation of facial nerve canal diameter in patients with ipsilateral recurrent idiopathic peripheral facial paralysis.

OBJECTIVE: This study evaluated the effects of the diameter of facial canal segments on the ipsilateral recurrence of idiopathic peripheral facial paralysis. METHOD: This study enrolled 20 patients with ipsilateral recurrent idiopathic peripheral facial paralysis. Measurements were made at the meatal foramen and mid-level of the labyrinthine segment and the narrowest and widest diameters of the mastoid and tympanic segments using the curved planar reformation technique with high-resolution computed tomography. RESULTS: The diameters of the labyrinthine segment measured at the meatal foramen and mid-level segments and the narrowest and widest diameters of the tympanic and mastoid segments on the recurrent paralytic side were significantly smaller than the diameters of the segments on the healthy side. CONCLUSION: The narrowness of the facial canal segments may be a risk factor in recurrent idiopathic peripheral facial paralysis.

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.

Evaluation of Bell's palsy in the cerebellopontine angle: An MRI study.

BACKGROUND: Evaluation of cranial nerve morphology through measuring cross-sectional area (CSA) on magnetic resonance imaging (MRI) is increasing day-by-day in clinical diseases. In Bell's palsy (BP), the manifestation of the enlarged CSA of the facial nerve (FN) may be used for diagnosis. This study aims to evaluate whether there is an enlargement of the cisternal FN in BP. METHODS: This retrospective study included 43 patients diagnosed with BP. In the reconstructed MRI, the long (LD) and short (SD) diameters of the paralytic and normal sides of the FNs located in the cerebellopontine angle were measured, and the CSA was calculated using the Radinsky formula. Before the radiologic measurement, a preliminary experiment was carried out on the rat sciatic nerve to be able to determine the actual nerve boundary on MRI. FINDINGS: There was a statistically significant relationship between paralytic and normal sides in the measurements of LD, SD, and CSA. The paralytic side was larger than the normal side in the cisternal FN. According to the Receiver Operating Characteristic (ROC) curve, BP can be estimated with 60% sensitivity and 70% specificity by the CSA of the FN more than 1.04 mm2 . As a result of the preliminary experiment, it was found that the actual nerve boundary was at approximately 50% intensity between the minimum and maximum values. CONCLUSION: Although entrapment of FN in the labyrinthine segment in BP was known, this study showed that the cisternal FN, which could be evaluated more conveniently, enlarged in the paralytic side compared with the normal side, and revealed the necessity of performing the comparison amongst the MRI studies on BP patients by a standardised measurement method. This study will also help clinicians to make a decision in the diagnosis of BP by giving a cut-off value for the CSA.

Diagnostic value of dynamic contrast-enhanced magnetic resonance imaging in Bell's palsy.

BACKGROUND: Bell's palsy (BP) is the most common form of acute facial nerve disorder and is characterized by rapid onset peripheral facial palsy of unknown etiology. PURPOSE: To explore the diagnostic value of dynamic contrast-enhanced (DCE) magnetic resonance imagine (MRI) in patients with BP particularly in involved segments. MATERIAL AND METHODS: A retrospective analysis was performed on the patients with BP who underwent routine MRI examinations and volumetric interpolated breath-hold examination (VIBE) sequence-based DCE-MRI before surgery in our department from January 2015 to July 2020. DCE-MRI data postprocessing was performed on Siemens Workstation Extended MR Work Space 2.6.3.5. Statistical analyses were performed using SPSS®v.19.0. The inter-observer reliability was evaluated with kappa identity test and McNemar's test. RESULTS: Twenty-three patients were included. On conventional contrast-enhanced MRI, the two observers were inconsistent in their diagnosis of lesion segments of facial nerve (Kappa 0.426, P = 0.009). Compared to the results of the surgery, the diagnostic consistency of both observers was general (Kappa 0.476, P < 0.001 and Kappa 0.430, P < 0.001, respectively). The diagnostic results of DCE-MRI for lesion segments of the facial nerve were consistent between the two observers (Kappa 0.929, P < 0.001). Compared to the results of the surgery, the diagnostic consistency of both observers was good (Kappa 0.753, P < 0.001 and Kappa 0.731, P < 0.001, respectively). CONCLUSION: Compared to conventional MRI, DCE-MRI has good stability and repeatability in the diagnosis of the lesion segments of the facial nerve as well as a good specificity and accuracy.

Risk of Leukemia in Children With Peripheral Facial Palsy.

Most children with peripheral facial palsy will not have a cause identified. Although leukemia can cause facial nerve palsy, the magnitude of the risk is unknown and recommendations for investigations are variable. We are currently conducting a randomized, placebo-controlled trial of prednisolone for the treatment of Bell's palsy in children within the Paediatric Research in Emergency Departments International Collaborative emergency research network. In the course of the assessment for eligibility of the trial, from 644 acute-onset facial palsy presentations we identified 5 children with previously undiagnosed leukemia. We estimate the rate of leukemia in children with acute-onset facial palsy who present to emergency departments to be 0.6% (95% confidence interval 0.2% to 1.6%). In accordance with these cases, we suggest consideration of a screening CBC count for acute-onset peripheral facial palsy presentations in children before initiation of corticosteroid treatment.

fMRI in Bell's Palsy: Cortical Activation is Associated with Clinical Status in the Acute and Recovery Phases.

BACKGROUND AND PURPOSE: Using functional magnetic resonance imaging (fMRI), we explored cortical activation in patients with acute Bell's palsy (BP) and analyzed its correlates with clinical status in the acute phase, and with 6-month outcome. METHODS: Twenty-four right-handed patients with acute BP within 15 days of onset and 24 healthy controls underwent fMRI during performance of unilateral active (hemi-smiling) and passive lip movement tasks with both the paretic and the normal lip. The degree of paresis was evaluated during the acute stage and at the 6-month follow up using the House-Brackmann (HB) grading scale. Complete recovery was defined as HB grade II or less at the end of the 6-month period. The difference in the HB grade (ΔHB) between the acute stage and the 6-month follow up was used to evaluate clinical improvement. RESULTS: There were 24 patients with unilateral acute BP. HB grades ranged from III to VI. At 6 months, 11 patients (46%) had completely recovered and 12 (50%) were partially improved. Compared with healthy subjects, BP patients had a significantly greater activation of the frontal areas and the insula ipsilateral to the paretic side. In BP patients, there was an inverse correlation between the activation of the ipsilateral hemisphere when moving the paretic side and the degree of paresis at baseline. An association was also observed between activation and clinical outcome (both complete recovery and ΔHB). CONCLUSIONS: In patients with BP, fMRI may represent a useful tool to predict long-term outcome, guide therapeutic approach, and monitor treatment response.

Diagnostic value of dynamic contrast-enhanced MRI in Bell's palsy: initial experience.

AIM: To assess the ability of conventional magnetic resonance imaging (MRI) combined with dynamic contrast-enhanced (DCE)-MRI to accurately identify characteristic imaging findings of Bell's palsy particularly in involved segments. MATERIALS AND METHODS: A retrospective analysis was performed on MRI images of patients with Bell's palsy in Shanghai Ninth People's Hospital from January 2015 to July 2019. DCE-MRI analysis was performed on a SIEMENS Workstation Extended MR Work Space 2.6.3.5 and by using the T1-weighted volumetric interpolated breath-hold examination (VIBE) sequence. Statistical analyses were performed by using SPSS v. 19.0. The chi-square test was used to compare the accuracy of conventional MRI versus DCE-MRI in imaging the involved segment of the facial nerve. RESULTS: Combined with the results of the surgery, the accuracy of conventional MRI in imaging the involved segments of the affected facial nerves was 38.5% (5/13), but was 92.3% (12/13) for DCE-MRI. There was a statistically significant difference between the two groups (chi-square value is 8.327, p = 0.004). CONCLUSION: DCE-MRI is useful to diagnose the involved segments of the affected facial nerve accurately compared to the conventional MRI. This approach has advantages both for the patient, in terms of safety, and for the physician, in terms of the accuracy of the diagnosis.