MRI evaluation of neurofibromatosis 2 patients: a standardized approach for accuracy in interpretation.

OBJECTIVE: To determine the level of agreement between local radiologists' and an experienced neuroradiologist's measurements of vestibular schwannomas. STUDY DESIGN: Prospective study with uniform magnetic resonance acquisition protocol parameters and reporting instructions across 30 magnetic resonance imaging facilities worldwide. SETTING: Multicenter natural history study of neurofibromatosis Type 2. SUBJECTS: One hundred fifteen magnetic resonance imaging examinations of 57 neurofibromatosis Type 2 patients older than 5 years of age. INTERVENTIONS: Thin-slice, postcontrast cranial magnetic resonance imaging. MAIN OUTCOME MEASURES: Spearman's rho interobserver association coefficient of vestibular schwannoma linear measurements. RESULTS: The local and experienced radiologist measurements and identification of tumors agreement was fair (kappa = 0.77). Discordant interpretations were adjudicated by another experienced neuroradiologist. CONCLUSION: The least interobserver variability was found in measurements of thin-slice postcontrast magnetic resonance imaging scans obtained at neurofibromatosis Type 2 centers in patients without previous operations and moderately sized tumors. If the schwannoma was difficult to assess, because of magnetic resonance imaging acquisition protocol, postoperative changes, or tumors smaller than 5 mm in greatest diameter, the neuroradiologist provided a more thorough assessment. The authors suggest uniform reporting criteria for vestibular schwannoma assessments to ensure clinically relevant information is communicated regarding vestibular schwannoma size.     

Magnetic resonance appearance of the inner ear after hearing-preservation surgery.

OBJECTIVE: To determine whether the appearance of the inner ear on T2-weighted follow-up magnetic resonance imaging correlates with hearing status after hearing-preservation surgery for vestibular schwannoma. STUDY DESIGN: Retrospective chart review. SETTING: Tertiary referral medical center. PATIENTS: The study includes patients undergoing hearing-preservation surgery for vestibular schwannoma from 1998 to 2003. INTERVENTION: Diagnostic evaluation with magnetic resonance imaging and audiometric evaluation. MAIN OUTCOME MEASURES: Hearing results as reported in charts was correlated with appearance of membranous labyrinth on T2-weighted magnetic resonance images obtained at least 1 year after surgery. RESULTS: Twenty-nine patients were identified, 16 of whom satisfied the inclusion criteria. All 16 of the patients underwent middle fossa removal of vestibular schwannoma. Serviceable hearing according to American Academy of Otolaryngology-Head and Neck Surgery criteria was preserved in eight patients (50%). Of the eight patients without serviceable hearing, six had the cochlear nerve sacrificed at the time of surgery. All patients with serviceable hearing had normal appearing cochleovestibular signal on T2-weighted images, whereas six of eight patients (75%) with no hearing or poor hearing had abnormal low signal in the inner ear, suggesting inner ear ossification. The positive predictive value of a normal labyrinth for preserved hearing was 90%, whereas the negative predictive value of an abnormal labyrinth for no hearing was 100%. All but one patient who had the cochlear nerve sacrificed showed abnormal morphology of the labyrinth on T2-weighted magnetic resonance imaging. CONCLUSION: We describe the T2-weighted magnetic resonance findings after hearing-preservation surgery for acoustic tumor removal. Loss of inner ear signal on T2-weighted images correlates with loss of hearing postoperatively, whereas preserved inner ear signal correlates with hearing preservation after middle fossa surgery for vestibular schwannoma removal.     

Neurovascular contacts in the inner ear canal and cerebellopontile angle. A methodologic comparison between CT with pneumocisternomeatography and MR angiography]

The interaction between arterial loops and the vestibulocochlear nerve is considered to be responsible for such clinical symptoms as progressive sensorineural hearing loss, tinnitus and vestibular dysfunction. Previously, neurovascular relationships were best demonstrated with invasive Gas-CT-cisternography, although this technique resulted in a low detection rate of 38%. Magnetic resonance angiography offers a non-invasive method for imaging vessel loops in the cerebellopontine angle without contrast medium in more than 90% of cases. A comparison between gas-CT-cisternography and magnetic resonance angiography in 9 patients revealed a superior simultaneous depiction of both anterior inferior cerebellar arteries with magnetic resonance angiography.     

Magnetic resonance imaging of the inner ear in patients with idiopathic sudden sensorineural hearing loss

Although gadolinium-enhanced magnetic resonance imaging (Gd-MRI) has been used to indicate the presence of a subclinical labyrinthitis in patients with idiopathic sudden sensorineural hearing loss (ISSHL), its sensitivity in daily clinical practice is unknown. We describe Gd-MRI findings in 27 ISSHL patients taking part in a prospective multicenter clinical trial. MRI findings were related to the severity of the hearing loss, vestibular involvement and the time interval between the occurrence of ISSHL and imaging. Pathological enhancement of the cochlea indicating a labyrinthitis was found in one patient with ISSHL. In 26 cases, no pathological enhancement could be established. Study results indicate that the present sensitivity of Gd-MRI is low for detecting subclinical viral labyrinthitis in patients with ISSHL. To improve the sensitivity of MRI in ISSHL, we recommend that imaging is performed as early as possible, preferably before treatment is started. Received: 17 November 1997 / Accepted: 8 May 1998     

Changes in endolymphatic hydrops after vestibular neurectomy observed in magnetic resonance imaging – A pilot study

ObjectivesThe aim was to evaluate endolymphatic hydrops in patients with Ménière's disease before and after vestibular neurectomy to verify if the endolymphatic space dilatation, observed in magnetic resonance imaging, regressed within several months after surgery.MethodsMagnetic resonance imaging was performed after intravenous gadolinium injection in four patients with unilateral definite Ménière's disease before and eight months after vestibular neurectomy. Clinical symptoms, audiovestibular tests, and endolymphatic hydrops in magnetic resonance imaging were evaluated.ResultsEndolymphatic hydrops was visualized in preoperative magnetic resonance imaging in three out of four analyzed patients. In the remaining one, an asymmetrical contrast enhancement in the affected ear was found. After the vestibular neurectomy, all four patients presented a complete resolution of vertigo episodes and improved functional level. Significant postoperative hearing deterioration was found in two patients. In the follow-up magnetic resonance imaging, no reduction of the endolymphatic hydrops was visualized. A reduction of asymmetrical contrast enhancement in one patient was found.ConclusionsMagnetic resonance imaging of the inner ear is a helpful diagnostic tool for Menière's disease. Vestibular neurectomy is an effective treatment for intractable vertigo; however, there is no endolymphatic hydrops regression evidence within several months after the surgery. Therefore, further studies with a long follow-up period and repeated magnetic resonance imaging are needed to assess the vestibular neurectomy's impact on endolymphatic hydrops. Nevertheless, magnetic resonance imaging supports the clinical diagnosis of Ménière's disease and may help understand its pathophysiology.     

Usher syndrome: an otoneurologic study

Usher syndrome is an autosomal recessive disorder characterized by severe hearing loss or deafness and retinitis pigmentosa. Eleven families with 25 affected members were studied. The test battery included genetic studies, clinical examination, audiological, ophthalmologic, and otoneurological tests, and magnetic resonance imaging. Sixteen affected persons had profound hearing loss or were considered anacusic, with absent bilateral vestibular responses. These patients had varying degrees of retinitis pigmentosa. These 16 patients were considered to have type I Usher syndrome. Nine persons were diagnosed as Usher type II with a moderate to profound hearing loss, normal vestibular function, and retinitis pigmentosa of varying degree. Magnetic resonance imaging was normal in all cases. Otoneurological tests indicated no central nervous system disturbances. The conclusion is that hearing loss and balance problems in Usher syndrome are due to inner ear damage with no evidence of central nervous system disturbances. Furthermore, the ataxia seen in Usher type I is due to a combination of retinitis pigmentosa and bilateral peripheral vestibular deficiency.     

Advanced techniques in magnetic resonance imaging in the evaluation of the large endolymphatic duct and sac syndrome

The purpose of this report is to compare temporal bone computed tomography (CT) to high-resolution magnetic resonance (MR) imaging using a novel thin-section fast spin echo (FSE) pulse sequence in identifying and characterizing patients with large vestibular aqueduct syndrome. Sixteen patients with sensorineural hearing loss and a CT diagnosis of large vestibular aqueduct(s) underwent high-resolution fast spin echo magnetic resonance imaging with dual, 3-in phased array receiver coils centered over the external auditory canals. Magnetic resonance imaging parameters included axial and oblique sagittal fast spin echo with an effective slice thickness of 1 mm contiguous. Thirty-eight patients with 76 normal inner ears who underwent MR imaging using this technique had their endolymphatic duct measured. MR alone identified the enlarged endolymphatic sac seen along with the large endolymphatic duct in all cases. Three cases (five inner ears) with enlarged bony vestibular aqueducts on CT showed no evidence of endolymphatic duct or sac enlargement on MR. MR alone identified a single case of mild cochlear anomaly in conjunction with an enlarged endolymphatic duct and sac. In the normal population the size of the normal endolymphatic duct at its midpoint measured from 0.1 to 1.4 mm. Thin-section, high-resolution fast spin echo MR imaging of the inner ear may be superior to CT in the evaluation of patients with the large vestibular aqueduct syndrome.     

Magnetic resonance imaging-detected inner ear hemorrhage as a potential cause of sudden sensorineural hearing loss

Purpose

The aim of this study is to assess the value of magnetic resonance imaging in identifying the etiology of sudden sensorineural hearing loss, and to correlate the high signals in the labyrinth with clinical features to identify if inner ear hemorrhage could be implicated.

Materials and methods

In this retrospective study, inner ear magnetic resonance imaging was given to 112 patients with sudden sensorineural hearing loss in the First Affiliated Hospital of Sun Yat-sen University from 2011 to 2012. The clinical features of patients with high signals in the labyrinth on magnetic resonance imaging were analyzed.

Results

Abnormal magnetic resonance images were identified in 13 (11.6%) patients. Retrocochlear pathology was found in six patients, including two cases of lacunar infarction, one case of multiple ischemias in the brainstem and bilateral centrum semiovale, two cases of acoustic neuroma, and one case of inner ear hemangioma. There were seven cases showing high signals in the labyrinth on unenhanced T1-weighted and fluid-attenuated inversion recovery images. Clinical features of these seven patients were characterized by irreversible profound hearing impairment and vestibular dysfunction. These findings were consistent with the hypothesis that their symptoms were caused by an inner ear hemorrhage.

Conclusion

The results indicate the importance of magnetic resonance imaging in sudden sensorineural hearing loss in patients. Moreover, patients with vestibular dysfunction and sudden profound hearing loss may have an inner ear hemorrhage evident by interpreting clinical and magnetic resonance imaging results.     

Giant vertebro-basilar aneurysm: an unusual cerebello-pontine angle lesion

Acoustic neuromas (vestibular schwannomas) comprise more than 90 per cent of all cerebello-pontine angle (CPA) lesions. We present a rare case of a giant vertebro-basilar aneurysm presenting as a CPA lesion. The general condition of the patient precluded the completion of the magnetic resonance (MR) sequences. The clinical and limited radiological results (T2 images alone, the features of which were not specific) initially did not lead to a specific diagnosis. To obtain further radiological information a computed tomography (CT) scan with contrast was performed and this revealed the lesion to be an aneurysm. The diagnostic difficulties and the treatment dilemmas of such a lesion are discussed. The importance of fine, axial, post-contrast CT arteriography with three-dimensional reconstruction, MR angiography and digital subtraction angiography are highlighted. The limitations of MR imaging in patients with CPA lesions are discussed.     

Acute vestibular neuritis visualized by 3-T magnetic resonance imaging with high-dose gadolinium

Sudden idiopathic unilateral loss of vestibular function without other signs or symptoms is called acute vestibular neuritis. It has been suggested that reactivation of human herpes simplex virus 1 could cause vestibular neuritis, Bell palsy, and sudden unilateral hearing loss. Enhancement of the facial nerve on gadolinium-enhanced magnetic resonance imaging (MRI) is a common finding in Bell palsy, but enhancement of the vestibular nerve has never been reported in acute vestibular neuritis. We present 2 consecutive cases of acute vestibular neuritis where high-field-strength MRI (3.0 T) with high-dose (0.3 mmol/kg of body weight) gadolinium-pentetic acid showed isolated enhancement of the vestibular nerve on the affected side only. These findings support the hypothesis of a viral and inflammatory cause of acute vestibular neuritis and might have implications for its treatment.     

Growth rate of non‐vestibular intracranial schwannomas

Growth rate of non‐vestibular intracranial schwannomas A group of nine patients with non‐vestibular intracranial neuromas (four jugular, four facial, one trigeminal) underwent an interval scanning management policy, with serial annual magnetic resonance (MR) imaging. Tumour volume was assessed by manual measurement of the tumour area by MR imaging. Tumour volume was assessed by manual measurement of the tumour area on MR imaging axial cuts. The mean tumour size at presentation was 4.6 cm³ (range 0.7–17.8 cm³). During a mean follow‐up of 36 months (range 22–50 months), five out of nine tumours grew significantly at a rate of more than 5% of their initial volume per year. Only those tumours growing at a rate of more than 20% initial volume per year exhibited symptom progression. During a 36‐month period of interval scanning, just over 50% of non‐vestibular intracranial neuromas exhibited significant growth. Symptom progression was found to be a strong indicator of a high growth rate. This proportion exhibiting growth is higher than that demonstrated by unilateral sporadic vestibular schwannomas, but less than in patients with neurofibromatosis II. Early treatment of non‐vestibular intracranial neuromas should therefore be considered.     

Vestibular schwannomas with fluid-fluid level

Vestibular schwannomas containing cystic parts are common, but it is extremely rare for a vestibular schwannoma to contain fluid-fluid levels. In this report, we present two cases of vestibular schwannoma with magnetic resonance imaging findings of a fluid-fluid level, and we discuss the radiological features and possible mechanism of fluid-fluid level formation.     

Magnetic resonance imaging vs palpation of cervical lymph node metastasis

In a series of 100 patients with head and neck carcinoma, the preoperative histopathologic findings of palpation and magnetic resonance imaging were compared with regard to both laterality and lymph node level (I through V). The overall error for palpation in detecting affected sides was 32%. Gadolinium-enhanced magnetic resonance images reliably upgraded 60% of the clinically negative necks, the overall error of magnetic resonance imaging being 16%. However, for both modalities, the sensitivity per level was too low to allow for selective neck dissections in case of only one positive level. These findings show that apart from primary tumor grading, magnetic resonance imaging can improve the preoperative grading of cervical lymph nodes. In selected cases, this may change the treatment plan to a "wait-and-see" policy or a more conservative type of neck dissection.     

Outcome of using magnetic resonance imaging as an initial screen to exclude vestibular schwannoma in patients presenting with unilateral tinnitus

The improved cost-effectiveness of gadolinium-enhanced magnetic resonance imaging (MRIg) as a diagnostic tool for vestibular schwannoma has resulted in smaller tumours being diagnosed. There has been a change in the clinical presentation of these tumours and up to four per cent may present with unilateral tinnitus. The limitation of auditory brain stem response (ABR) as a screening tool that detects small tumours is recognized and there is a strong argument for using MRIg as the initial investigation. Various screening guidelines have been proposed, some include submitting patients with unilateral tinnitus for MRIg. This report describes the findings in a group of 174 patients presenting with unilateral tinnitus who underwent MRIg as part of a guideline-directed screen to exclude vestibular schwannoma. Five patients had a cause for their tinnitus diagnosed, one a vestibular schwannoma. Two had intracranial aneurysms and another three had pathology revealed that merited onward referral. A further nine patients had incidental findings that neither accounted for their symptoms nor needed further investigation or referral. The rationale for screening these patients with MRIg is discussed.     

Cyclin D1 expression and histopathologic features in vestibular schwannomas.

OBJECTIVE: To evaluate cyclin D1 expression in vestibular schwannoma and its relationship with histologic, clinical, and radiologic features. PATIENTS: Twenty-one patients with histologically confirmed vestibular schwannoma. INTERVENTION: Immunohistochemistry analysis was performed with anticyclin D1. Histopathologic features studied included Antoni pattern and nuclear and stromal degenerative changes. Clinical charts, audiometric data, and magnetic resonance imaging characteristics were reviewed. MAIN OUTCOME MEASURES: Cyclin D1 expression and its association with histologic, clinical, and radiologic findings. RESULTS: Cyclin D1 expression was found in 52% of cases. Cyclin D1 expression was more frequent in right-sided tumors (p = 0.02) and in tumors with nuclear degenerative changes (p < 0.0001). Patients with negative cyclin D1 expression had longer duration of deafness (p = 0.02) and higher 2,000-Hz hearing thresholds (p = 0.04) than cyclin D1+ patients. CONCLUSION: Cyclin D1 expression, present in nearly half of the cases, may play a role in the development of these tumors. Further studies are needed to fully understand the contributions of histopathologic and immunohistochemical factors to vestibular schwannoma biological activity.     

3D-constructive interference into steady state (3D-CISS) labyrinth signal alteration in patients with vestibular schwannoma

Objective

To evaluate signal intensity of the inner ear using 3D-CISS imaging and correlated signal characteristics in patients with vestibular schwannoma to neuro-otological symptoms.

蜗神经磁共振成像在感音神经性聋中的应用

目的探讨蜗神经磁共振成像在感音神经性聋(SNHL)中的应用价值。方法采用GE TwinExct1.5T磁共振扫描仪对130例(260耳)SNHL患者进行蜗神经磁共振成像及内耳水成像。蜗神经成像序列为斜矢状位FRFSET2加权像,内耳水成像为3DFIESTA序列。结果 90例大于等于18岁的患者中,85例170耳显示蜗神经、迷路正常;1例2耳前庭导水管扩大;1例1耳蜗神经信号缺失;3例6耳蜗神经细小;40例小于18岁的患者中,19例38耳显示蜗神经、迷路正常;2例3耳Michel畸形;6例12耳Mondini畸形;1例2耳共腔畸形;12例24耳前庭导水管扩大;21例畸形中7例14耳蜗神经信号缺失。2例4耳显示内听道狭窄伴蜗神经细小。结论磁共振内耳成像对诊断SNHL有着重要的价值,对判断患者内耳蜗神经发育情况及内耳畸形有着不可替代的作用,是这类患者进行人工耳蜗植入术前必要检查。     

Postoperative imaging and follow-up of vestibular schwannomas.

OBJECTIVE: No standards exist regarding patient follow-up after complete vestibular schwannoma resection. We surveyed neurotologists and neurosurgeons to determine practice patterns. STUDY DESIGN: A nonrandomized sample of American Neurotology Society and North American Skull Base Society members was surveyed. Questions concerned years in practice, experience with vestibular schwannoma surgery, and postoperative follow-up algorithms given the scenario of complete gross tumor removal. Data were collected, tallied, and statistically analyzed. SETTING: Academic and private practice neurotologists and neurosurgeons. SUBJECTS: Nonrandom sample of American Neurotology Society and North American Skull Base Society members. MAIN OUTCOME MEASURES: Number of postoperative magnetic resonance imaging scans, timing of magnetic resonance imaging scans, timing of final magnetic resonance imaging scan, timing of final visit, and variability between specialties. RESULTS: Four hundred ninety-eight surveys were sent and 135 were returned (27.1%). The average number of postoperative magnetic resonance imaging scans was 3.6 for neurotologists (range, 1-11) and 5.6 for neurosurgeons (range, 1-13). This was statistically significant (p >0.001). There was no correlation between number of magnetic resonance imaging scans and either years in practice or tumor experience. Average length of follow-up varied greatly (1 year to lifetime) but was most commonly 5 years. Eight percent of neurotologists varied their postoperative routine on the basis of surgical approach, whereas none of the neurosurgeons did. CONCLUSION: There remains no standard postoperative imaging algorithm for patients after complete vestibular schwannoma resection.     

Congenital inner ear malformations without sensorineural hearing loss in children

Inner ear malformations are frequently found in patients with congenital hearing loss. It has been reported that normal hearing is rare in patients with severe inner ear vestibular malformations. A 9-year-old boy had had complained of recurrent dizziness and disequilibrium for 2 months. Clinical and neuro-otological examinations showed peripheral involvement of the vestibular system, while audiological investigation was normal. High-resolution magnetic resonance imaging, with three-dimensional reconstruction, showed dysplasia of the bilateral lateral semicircular canals (LSCCs). Isolated vestibular malformation might not be as rare as previously thought, and should be examined by imaging of the temporal bone.