Contrast-enhanced MR imaging of the facial nerve in 11 patients with Bell's palsy

Contrast-enhanced MR images (at 1.5 T) were obtained in 11 patients with facial palsy. The group included five people with acute idiopathic facial (Bell's) palsy, three with chronic idiopathic facial palsy, and one each with acute facial palsy after local radiation therapy, acute facial palsy resulting from herpes zoster virus infection, and facial palsy caused by facial neuroma. Eight of the 11 patients demonstrated marked enhancement of the affected facial nerve from the labyrinthine portion through the descending canal. Three patients also demonstrated mild enhancement of the distal canalicular portion of the facial nerve, simulating small distal acoustic neuromas. No difference in the pattern of enhancement between the acute or chronic Bell's palsy patients was seen. Radiographic resolution appeared to lag behind clinical resolution. The facial neuroma appeared distinct from the other lesions as a focally enhancing mass. The enhancement pattern in the Bell's group correlated with the histopathologic features of Bell's palsy and is consistent with the viral hypothesis of the syndrome. Thin-section contrast-enhanced MR scans are recommended for individuals with atypical presentation of facial paralysis. In the proper clinical setting, contrast-enhanced MR imaging may permit a positive radiographic diagnosis of Bell's palsy, which has previously been a diagnosis of exclusion.     

Contrast-enhanced MR imaging of the facial nerve in 11 patients with Bell's palsy

Contrast-enhanced MR images (at 1.5 T) were obtained in 11 patients with facial palsy. The group included five people with acute idiopathic facial (Bell's) palsy, three with chronic idiopathic facial palsy, and one each with acute facial palsy after local radiation therapy, acute facial palsy resulting from herpes zoster virus infection, and facial palsy caused by facial neuroma. Eight of the 11 patients demonstrated marked enhancement of the affected facial nerve from the labyrinthine portion through the descending canal. Three patients also demonstrated mild enhancement of the distal canalicular portion of the facial nerve, simulating small distal acoustic neuromas. No difference in the pattern of enhancement between the acute or chronic Bell's palsy patients was seen. Radiographic resolution appeared to lag behind clinical resolution. The facial neuroma appeared distinct from the other lesions as a focally enhancing mass. The enhancement pattern in the Bell's group correlated with the histopathologic features of Bell's palsy and is consistent with the viral hypothesis of the syndrome. Thin-section contrast-enhanced MR scans are recommended for individuals with atypical presentation of facial paralysis. In the proper clinical setting, contrast-enhanced MR imaging may permit a positive radiographic diagnosis of Bell's palsy, which has previously been a diagnosis of exclusion.     

Facial nerve palsy: evaluation by contrast-enhanced MR imaging

AIM: The purpose of this study was to investigate the value of contrast-enhanced magnetic resonance (MR) imaging in patients with peripheral facial nerve palsy. MATERIALS AND METHODS: MR imaging was performed in 147 patients with facial nerve palsy, using a 1.0 T unit. All of 147 patients were evaluated by contrast-enhanced MR imaging and the pattern of enhancement was compared with that in 300 control subjects evaluated for suspected acoustic neurinoma. RESULTS: The intrameatal and labyrinthine segments of the normal facial nerve did not show enhancement, whereas enhancement of the distal intrameatal segment and the labyrinthine segment was respectively found in 67% and 43% of patients with Bell's palsy. The geniculate ganglion or the tympanic-mastoid segment was enhanced in 21% of normal controls versus 91% of patients with Bell's palsy. Abnormal enhancement of the non-paralyzed facial nerve was found in a patient with bilateral temporal bone fracture. CONCLUSION: Enhancement of the distal intrameatal and labyrinthine segments is specific for facial nerve palsy. Contrast-enhanced MR imaging can reveal inflammatory facial nerve lesions and traumatic nerve injury, including clinically silent damage in trauma.     

Intensity of MR contrast enhancement does not correspond to clinical and electroneurographic findings in acute inflammatory facial nerve palsy.

PURPOSETo determine the value of MR contrast enhancement in predicting the course of acute inflammatory facial nerve palsy and in selecting patients for surgical decompression.METHODSSix patients with an acute inflammatory incomplete or complete peripheral facial nerve palsy (five idiopathic and one herpetic in origin) had repeated MR imaging studies with and without contrast enhancement, electroneurography, and clinical examinations to establish a connection between the intensity of contrast enhancement on MR images, the clinical condition, and the electrophysiological data. The examinations were performed every second day starting on the first day of admission until clinical recovery was proved by clinical deblockage (spontaneous clinical improvement). The last examination was performed 3 months after the onset of the facial nerve palsy.RESULTSAn abnormal, very intense contrast enhancement of the facial nerve was always present in the distal intrameatal and proximal tympanic segments and in the geniculate ganglion. The labyrinthine segment exhibited a mild to moderate enhancement, and the distal tympanic and mastoid segments showed a moderate to intense enhancement. The intensity of contrast enhancement did not correspond to the severity, duration, or course of the facial nerve palsy, and the electroneurographic data had no predictive value in indicating the severity of the inflammatory process. Three months after clinical recovery, a persistent and more or less unchanged or even slightly more intense contrast enhancement was observed.CONCLUSIONThe long-lasting intense contrast enhancement seen in the facial nerve segments of patients who have acute peripheral inflammatory facial nerve palsy is explained by a two-phase breakdown of the blood-nerve barrier.     

Idiopathic,herpetic, and HIV-associated facial nerve palsies: abnormal MR enhancement patterns.

PURPOSETo determine specific criteria that can be used to define normal versus abnormal MR contrast enhancement of the facial nerve.METHODSTwenty-three patients with acute unilateral inflammatory peripheral facial nerve palsy were examined on a 1.5-T MR using multiplanar T1-weighted spin-echo sequences before and after injection of gadopentetate dimeglumine. These MR patterns were compared with those of healthy control subjects.RESULTSThe normal facial nerve usually showed a mild to moderate enhancement of the geniculate ganglion and the tympanic-mastoid segment. The intracanalicular-labyrinthine segment did not enhance. All patients showed abnormal enhancement of the distal intracanalicular and the labyrinthine segment. An intense enhancement could be observed in the geniculate ganglion and the proximal tympanic segment, especially in herpetic palsy. Associated enhancement of the vestibulocochlear nerve was seen in herpetic and idiopathic palsy. Enhancement of the inner ear structures was detected only in herpetic palsy.CONCLUSIONSAbnormal contrast enhancement of the distal intracanalicular and the labyrinthine facial nerve segment is observed in all patients and is the only diagnostically reliable MR feature proving an inflammatory facial nerve lesion. The intense enhancement of the geniculate ganglion and the proximal tympanic segment is possibly correlated with the reactivation of the latent infection in the sensory ganglion. The abnormal enhancement results from breakdown of the blood-peripheral nerve barrier and/or from venous congestion in the venous plexuses of the epi- and perineurium.     

High-intensity facial nerve lesions on T2-weighted images in chronic persistent facial nerve palsy

Our aim was to estimate the value of MRI in detecting irreversibly paralysed facial nerves. We examined 95 consecutive patients with a facial nerve palsy (14 with a persistent palsy, and 81 with good recovery), using a 1.0 T unit, with T2-weighted and contrast-enhanced T1-weighted images. The geniculate ganglion and tympanic segment had gave high signal on T2-weighted images in the chronic stage of persistent palsy, but not in acute palsy. The enhancement pattern of the facial nerve in the chronic persistent facial nerve palsy is similar to that in the acute palsy with good recovery. These findings suggest that T2-weighted MRI can be used to show severely damaged facial nerves. Received: 13 December 1999 Accepted: 2 May 2000     

Etude angiographique des paralysies faciales

Summary Many arguments lead us to think that a possible etiologic factor in idiopathic Bell's palsy is the ischemia of the facial nerve and that angiography could help in diagnosis: (1) the rapid progress of the paralysis; (2) the correlation between Bell's palsy occurring after embolization of the internal maxillary artery, the middle meningeal artery, the occipital or posterior auricular artery, and their participation in the blood supply of the facial nerve; (3) the already known ischemic third nerve paralysis reported in diabetes and extending further to the facial nerve.Even if it is technically impossible to study Bell's palsy by angiography, it is interesting to understand and consider some complications of embolization and perhaps to envisage a new kind of treatment.     

MRI of the facial nerve in idiopathic facial palsy

The purpose of this prospective study was to define the enhancement pattern of the facial nerve in idiopathic facial paralysis (Bell's palsy) on magnetic resonance (MR) imaging with routine doses of gadolinium-DTPA (0.1 mmol/kg). Using 0.5T imager, 24 patients were examined with a mean interval time of 13.7 days between the onset of symptoms and the MR examination. Contralateral asymptomatic facial nerves constituted the control group and five of the normal facial nerves (20.8%) showed enhancement confined to the geniculate ganglion. Hence, contrast enhancement limited to the geniculate ganglion in the abnormal facial nerve (3 of 24) was referred to as equivocal. Not encountered in any of the normal facial nerves, enhancement of other segments alone or associated with geniculate ganglion enhancement was considered to be abnormal and noted in 70.8% of the symptomatic facial nerves. The most frequently enhancing segments were the geniculate ganglion and the distal intracanalicular segment. Correspondence to: I. Saatçi     

Magnetic resonance imaging of the intratemporal facial nerve in idiopathic peripheral facial palsy

The aim of this study was to investigate the prevalence of facial nerve involvement with gadolinium-enhanced magnetic resonance imaging (Gd-MRI) in patients with idiopathic peripheral facial palsy (IPFP), and to discuss the localization and the pattern of enhancement. A total of 13 patients (9 female, 4 male) with IFPF were included in this study. Topographic tests and electromyography (EMG) were performed, and MRI was taken. Ten subjects whose cranial MRIs were taken for nonorganic pathology served as the control group. Twelve of 13 paralytic facial nerves had enhancement on postcontrast images. Two facial nerves of the control group demonstrated enhancement. We found a correlation between the enhancement of the facial nerve and the time for recovery. The average time from the onset of facial palsy to the recovery in patients with enhancement was 14 weeks, whereas it was 6 weeks in patient with no enhancement. Finally, all patients had complete recovery of the facial nerve function. We concluded that contrast enhancement of the paralytic facial nerve can be a radiological sign of a neural inflammation and may indicate a prolonged recovery.     

T2-weighted three-dimensional fast spin-echo MR in inflammatory peripheral facial nerve palsy.

PURPOSEOur objective was to identify histologically and intraoperatively verified focal nerve thickening of the distal intrameatal segment on three-dimensional fast spin-echo (FSE) T2-weighted MR images as a new diagnostic criterion in patients with inflammatory peripheral facial nerve palsy.METHODSTwenty-two patients with clinically diagnosed unilateral (n = 20) or bilateral (n = 2) inflammatory peripheral facial nerve palsy were examined on a 1.5-T MR imager using noncontrast and contrast-enhanced T1-weighted SE sequences and 3-D T2-weighted FSE sequences with secondary reformations. Abnormal contrast enhancement and possible focal nerve thickening of the distal intrameatal segment, labyrinthine nerve segment, and geniculate ganglion region were analyzed prospectively.RESULTSIn all patients, the T1-weighted postcontrast SE images showed characteristic smooth, linear, abnormally intense contrast enhancement of the distal intrameatal segment, indicating peripheral inflammatory nerve palsy. In 23 nerves (96%) a focal bulbous nerve thickening of the distal intrameatal segment was observed on 3-D T2-weighted FSE images. In 100% of patients with peripheral inflammatory facial nerve palsy, postcontrast T1-weighted SE images showed a smooth, linear, and abnormally intense contrast enhancement of the distal intrameatal segment; reformatted very thin 3-D T2-weighted FSE images showed a focal bulbous nerve thickening of the distal intrameatal segment in 96% of patients. These findings corresponded to intraoperative and histologic findings.CONCLUSIONThree-dimensional T2-weighted FSE sequences are fast and cheap compared with T1-weighted postcontrast images, but secondary reformations are time-consuming and require exact anatomic knowledge for careful analysis of the different nerve segments.     

Bell's palsy: what is the prognostic value of measurements of signal intensity increases with contrast enhancement on MRI?

Our objective was to assess the prognostic value of measurements of the degree of contrast enhancement of the intratemporal segments of the facial nerve. We prospectively obtained MRI, slice thickness <1 mm of 20 patients with a facial palsy on the first day of inpatient treatment, and measured contrast enhancement of the nerve. The data were compared with compound muscle action potential (CMAP) measurements and the clinical course. Analysis of the initial enabled differentiation of three patients whose palsy was to show no improvement from 17 whose palsy was to resolve as expected. No patient with a poor outcome showed lesser increase in signal in the internal auditory canal, pars tympanica and pars mastoidea than patients who fully recovered. In no patient who had been diagnosed on the basis of the initial MRI as having a "normal" palsy was the amplitude of the (CMAP) reduced to less than 20% that of the normal side. Measurement of contrast enhancement was thus shown to be a prognostic indicator and may provide a basis for a differential treatment of facial palsy.     

Exploration artériographique du Nerf Facial Intra-Pétreux: Embryologie et Aspect Radio-Anatomiques Normaux

Summary The normal development of the hyoidostapedial system and its branches and anastomosis are outlined. The intrapetrous facial nerve receives its arterial supply from this network. The arterial arch of the facial nerve is seen more frequently in angiograms of infants than in those of adults. The fact that the same vessel supplies the VIIth and the Vth nerves suggests that an ischemic mechanism may frequently be involved in Bell's palsy. The facial nerve from the point of view of its arterial supply must be considered as a nerve of the middle fossa and represent the major risk of embolization in the propinal middle meningeal artery.     

外伤性面瘫的多层螺旋CT研究

目的探讨多层螺旋CT(MSCT)在外伤性面瘫中的应用价值。方法用MSCT对41例外伤性面瘫的颞骨行高分辨率轴面扫描。用Ph ilipsMx8000MSCT工作站,行岩锥感兴趣区的多平面重建(MPR)及面神经管的曲面重建(CPR)。观察骨折类型,骨折线的走行,中耳腔、乳突积血及外耳、中耳、内耳和面神经管的受累情况。结果41例患者中,39例颞骨有不同部位、不同类型的骨折,其中岩骨纵行骨折34例,横行骨折2例,混合型2例,1例岩骨无骨折,但颞骨鳞部骨折,2例未发现骨折。其中2例为双侧岩骨骨折。面神经管的CPR及MPR显示21例患者面神经管受累,9例可见骨碎片。结论MSCT扫描及重建技术能清晰显示面神经管的全貌及其损伤,对外伤性面瘫的诊断有重要意义。     

Abducens nerve enhancement demonstrated by multiplanar reconstruction of contrast-enhanced three-dimensional MRI

We describe contrast enhancement of the cisternal portion of the abducens nerve and discuss its clinical significance. We examined 67 patients with ophthalmoplegia using contrast-enhanced 3-dimensional (3D) MRI with multiplanar reconstruction along the nerves and found 16 patients (ten men, six women), aged 10–73 years (mean 34.4 years), with contrast enhancement of the abducens nerve. Of the 36 patients who had an abducens palsy, 14 (39 %) showed contrast enhancement. In the 16 patients, 23 abducens nerves enhanced; 13 were symptomatic and 10 asymptomatic at the time. The causes were disseminated tumour (1), an inflammatory process (3), trauma (2), ischaemia (2) and autoimmune diseases (8), such as the Miller Fisher syndrome, acute ophthalmoparesis, polyneuropathy and multiple sclerosis. Abducens and/or oculomotor nerve enhancement was the only abnormality on MRI in the patients with traumatic or ischaemic neuropathy or autoimmune diseases. There were 14 patients who recovered fully within 1–6 months after treatment, and resolution of the enhancement correlated well with recovery. Received: 27 September 1999 Accepted: 23 March 2000     

MR imaging of facial nerve enhancement in Bell palsy or after temporal bone surgery

The authors evaluated magnetic resonance (MR) images obtained with intravenously administered gadolinium in ten patients who had facial paralysis and no facial nerve tumor. In patients with either Bell palsy (four patients) or facial paralysis after temporal bone surgery (six patients), intratemporal facial nerve enhancement was seen. Facial nerve enhancement on MR images proved to be a nonspecific finding.     

An unusual case of facial nerve palsy following soccer related minor head injury

A 16 year old amateur soccer player sustained a minor head injury while contesting a ball in the air. He was unconscious for two minutes and remained “dizzy” for about an hour. After two days he developed a profound left lower motor neurone facial nerve palsy. He was found to have a complex fracture of the left petrous temporal bone, with fluid in the left middle ear and left mastoid. Treatment was conservative with oral steroids and oral co‐amoxiclav and a left myringotomy to decompress his middle ear. The spectrum of aetiology, presentation, and prognosis for facial nerve injuries is discussed.     

Enhancement pattern of the normal facial nerve at 3.0 T temporal MRI

The purpose of this study was to evaluate the enhancement pattern of the normal facial nerve at 3.0 T temporal MRI. We reviewed the medical records of 20 patients and evaluated 40 clinically normal facial nerves demonstrated by 3.0 T temporal MRI. The grade of enhancement of the facial nerve was visually scaled from 0 to 3. The patients comprised 11 men and 9 women, and the mean age was 39.7 years. The reasons for the MRI were sudden hearing loss (11 patients), Méniàre''s disease (6) and tinnitus (7). Temporal MR scans were obtained by fluid-attenuated inversion-recovery (FLAIR) and diffusion-weighted imaging of the brain; three-dimensional (3D) fast imaging employing steady-state acquisition (FIESTA) images of the temporal bone with a 0.77 mm thickness, and pre-contrast and contrast-enhanced 3D spoiled gradient record acquisition in the steady state (SPGR) of the temporal bone with a 1 mm thickness, were obtained with 3.0 T MR scanning. 40 nerves (100%) were visibly enhanced along at least one segment of the facial nerve. The enhanced segments included the geniculate ganglion (77.5%), tympanic segment (37.5%) and mastoid segment (100%). Even the facial nerve in the internal auditory canal (15%) and labyrinthine segments (5%) showed mild enhancement. The use of high-resolution, high signal-to-noise ratio (with 3 T MRI), thin-section contrast-enhanced 3D SPGR sequences showed enhancement of the normal facial nerve along the whole course of the nerve; however, only mild enhancement was observed in areas associated with acute neuritis, namely the canalicular and labyrinthine segment. Imaging of the facial nerve is useful for the evaluation of pathological conditions. MRI of the facial nerve is usually performed selectively in cases of peripheral facial nerve palsy in patients with an atypical presentation or delayed recovery to exclude space-occupying lesions. The gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) contrast pulse sequence is the most informative MRI procedure for evaluation of facial nerve pathology [1]. Although many studies involving MRI of normal and paralysed facial nerves have been performed [2–10], there are no reports on the enhancement pattern of normal and abnormal facial nerves with 3.0 T MR scanning. The 3.0 T MR scan provides a higher signal-to-noise ratio (SNR), which allows a higher imaging matrix, thinner slices and a shorter time for scanning [11].The purpose of this retrospective study was to evaluate the enhancement pattern of normal facial nerves, bilaterally, with 3.0 T temporal MRI.     

MR imaging for evaluation of severe facial nerve damage in patients with facial nerve palsy

PURPOSE: To evaluate the usefulness of MR imaging for the detection of severe facial nerve damage in patients with facial nerve palsy. MATERIALS AND METHODS: We retrospectively reviewed 26 consecutive patients with facial nerve palsy (13 non-responders and 13 responders). T1-weighted, T2-weighted, and postcontrast T1-weighted images were obtained in all patients. FLAIR images were also obtained in 3 non-responders. RESULTS: The geniculate ganglion, labyrinthine segment, and tympanic segment or mastoid segment showed high signal intensity on T2-weighted images in 9 of 13 non-responders, whereas high signal intensity of the nerve was only seen in 1 of 13 responders. FLAIR imaging revealed high signal intensity lesions of the distal intrameatal segment in 2 non-responders. Contrast enhancement of the facial nerve showed a similar pattern in non-responders and responders. High signal intensity lesions on T2-weighted or FLAIR images showed enhancement on postcontrast T1-weighted images. CONCLUSION: These results suggest that a high signal intensity area on T2-weighted images is a marker of severe facial nerve damage. FLAIR imaging is useful for identification of T2-prolongation in the distal intrameatal segment.     

Bell palsy: quantitative analysis of MR imaging data as a method of predicting outcome

PURPOSE: To assess the prognostic value of quantitative analyses of region-of-interest (ROI) magnetic resonance (MR) imaging data in patients with acute facial nerve palsy. MATERIALS AND METHODS: In a single-blinded study, MR images were obtained in 39 patients (32 men and seven women; age range, 18-75 years; average age, 37.9 years) with acute facial nerve palsy. MR images were obtained before the 6th day of illness, on the first day of standard inpatient treatment with high-dose steroids. Signal intensity (SI) was measured at ROIs in each of five segments (internal auditory canal [IAC]; geniculate ganglion; and labyrinth, tympanic, and mastoid segments) of the intratemporal portion of the facial nerve and quantitatively analyzed. The SI measurements in the five segments were summed and divided by 100 to provide a basis for establishing an MR imaging index. SI increases and MR imaging indexes were compared with available clinical findings and electrophysiologic data. RESULTS: Data for all 39 patients could be analyzed. The MR imaging index was significantly higher in patients with poor outcomes than in patients with favorable outcomes (specificity, 97%; sensitivity, 75%; P <.01). The SI increases in the IAC were significantly different between patients who progressed to full recovery (mean increase, 45.7%) and patients who developed chronic facial paralysis (mean increase, 156.5%) (sensitivity, 100%; specificity, 97%; P <.001). The results of differentiating between patients with good and those with poor outcomes on the basis of SI measurements in the IAC were found to be in complete agreement with electrophysiologic data. CONCLUSION: Quantitative analysis of ROI MR imaging data is a valid method of predicting the outcome of acute facial nerve palsy during the first days after onset of symptoms and thus at a time when it is not yet possible to obtain valuable prognostic information by using electrophysiologic methods.     

MRI of mastoid and middle ear disease

MR and CT are complementary studies in evaluating inflammatory disease or neoplasms of the mastoid and middle ear cavities. CT should be performed prior to MR in the evaluation of patients with primary temporal bone pathology because of its ability to detect and delineate both soft tissue and bony abnormalities. CT should be performed whenever intratympanic or facial nerve pathology is suspected, even if the MR examination is normal. MR can be used to further characterize tympanic cavity masses as effusion, glomus tumor, hemorrhage or cholesterol granuloma. The prospect of Gd-DTPA-enhanced MR promises increased sophistication in the detection of glomus tumors and facial nerve neuromas. Noncontrast MR cannot differentiate between cholesteatoma and granulation tissue. The efficacy of Gd-DTPA in inflammatory disease of the temporal bone awaits further investigation.