Quantitative Analysis of the Facial Nerve Using Contrast-Enhanced Three Dimensional FLAIR-VISTA Imaging in Pediatric Bell's Palsy

PURPOSE: To evaluate the usefulness of quantitative analysis of the facial nerve using contrast-enhanced three-dimensional (CE 3D) fluid-attenuated inversion recovery-volume isotopic turbo spin echo acquisition (FLAIR-VISTA) for the diagnosis of Bell's palsy in pediatric patients. MATERIALS AND METHODS: Twelve patients (24 nerves) with unilateral acute facial nerve palsy underwent MRI from March 2014 through March 2015. The unaffected sides were included as a control group. First, for quantitative analysis, the signal intensity (SI) and relative SI (RSI) for canalicular, labyrinthine, geniculate ganglion, tympanic, and mastoid segments of the facial nerve on CE 3D FLAIR images were measured using regions of interest (ROI). Second, CE 3D FLAIR and CE T1-SE images were analyzed to compare their diagnostic performance by visual assessment (VA). The sensitivity, specificity, and accuracy of RSI measurement and VA were compared. RESULTS: The absolute SI of canalicular and mastoid segments and the sum of the five mean SI (total SI) were higher in the palsy group than in the control group, but with no significant differences. The RSI of the canalicular segment and the total SI were significantly correlated with the symptomatic side (P = 0.028 and 0.015). In 11/12 (91.6%) patients, the RSI of total SI resulted in accurate detection of the affected side. The sensitivity, specificity, and accuracy for detecting Bell's palsy were higher with RSI measurement than with VA of CE 3D FLAIR images, while those with VA of CE T1-SE images were higher than those with VA of CE 3D FLAIR images. CONCLUSION: Quantitative analysis of the facial nerve using CE 3D FLAIR imaging can be useful for increasing the diagnostic performance in children with Bell's palsy when difficult to diagnose using VA alone. With regard to VA, the diagnostic performance of CE T1-SE imaging is superior to that of CE 3D FLAIR imaging in children. Further studies including larger populations are necessary.

The Correlation Analysis of Endolymphatic Hydrops Degree in Vestibule and the Symptoms and Audiovestibular Functions in Patients with Meniere’s Disease / 听力学及言语疾病杂志

Objective To evaluate the correlation between the endolymphatic hydrops in vestibule and symp‐toms ,audiovestibular functions in patients with Meniere's disease .Methods Twenty -four hours after bilateral intra-tympanic 8 times diluted gadolinium administration , three - dimensional fluid - attenuated inversion recovery MRI ,using a three-Tesla unit ,was performed in 34 patients .The extent of endolymphatic hydrops in the MRI images was assessed and compared the hydrops with age ,duration ,stage of the disease ,frequency of attacks ,pure tone audiometry ,caloric test ,electrocochleography and vestibular evoked myogenic potentials .Results Thirty -four patients showed different levels of enhancement of perilymth in the inner ears .In these patients ,obvious signs of endolymphatic hydrops were visualized ,including 8 slight hydrops ,11 mild hydrops and 15 significant hydrops . In all 34 patients ,the results of PTA were 9 dB HL to 90 dB HL ,with average of 43 .56 dB HL and there were 21 abnormal and 13 normal patients in caloric test with a diagnostic rate 61 .76% ;17 normal ,7 abnormal and 10 not elicited patients in VEMP with a diagnostic rate 50% ;22 abnormal and 12 normal patients in electrocochleography with a diagnostic rate 64 .71% .There were almost no complications in all 34 patients after bilateral intra-tympanic injec‐tion except short vertigo among 5 of them .A statistically significant correlation was found between degrees of en‐dolymphatic hydrops in vestibule and age ,stage of the disease and VEMP (P 0 .05) and the correlation coefficient were 0 .494 ,0 .568 ,0 .590 , 0 .495 ,respectively .Conclusion The degree of endolymphatic hydrops in Ménière's disease has significant correlation with age ,VEMP ,stage of the disease and pure tone audiometry .No significant correlation was found between hy‐drops and duration ,frequency of attacks ,functional level scale ,caloric test and electrocochleography .

Role of 3D FLAIR in demonstration of peripheral lesions of brainstem and cranial neuropathies.

Aim: We present a pictorial review of 3D FLAIR images depicting its importance in demonstrating the peripheral lesions of brainstem particularly in relation to attachment of cranial nerves and cranial neuropathies and particularly in context of patients with multiple sclerosis (MS). Discussion: T2 axials and routine 2D FLAIR have drawbacks in depicting the lesions on the peripheral aspects of brainstem. Such lesions are commonly found in MS. The revised McDonald’s criteria (2010) put equal emphasis on periventricular, juxtacortical, infratentorial and cord lesions. Detection of peripheral lesions thus play important role in fulfilling the criteria of dissemination in space and also provide anatomic correlate in several cranial nerve palsies. In clinically isolated syndromes, demonstration of lesions at the site of affected cranial nerves increase diagnostic confidence and exclude other potential disease processes. Ability to show signal changes at cranial nerve attachment can also potentially prevent a false attribution of symptoms to neurovascular compression. Conclusion: We propose that 3D FLAIR sequence is extremely useful in detecting abnormalities on the surface of brainstem and cranial nerve attachments and should be performed in all patients of MS and cranial nerve palsies.

A rare case of third ventricular epidermoid cyst as seen by newer MRI sequences.

Aim: We describe a 52 year old gentleman who had a third ventricular lesion, presumed to be epidermoid cyst, which is very rare. We also describe the appearances of this rare condition on newer MRI sequences. Presentation of Case: Third ventricle is a rare site of epidermoid cysts and difficult to visualise specially in routine MRI sequences. We used 3D FLAIR sequence as part of routine MRI protocol that was helpful in raising suspicion initially, aided by clinical presentation. Subsequent 3D T2 SPACE sequence confirmed the presence of abnormality. Discussion: The case highlights the importance of high resolution 3D FLAIR sequence as part of initial MRI protocol that is devoid of CSF flow artefacts and therefore helpful for small intraventricular lesions. Importance of 3D T2 SPACE is also highlighted which is another new MRI sequence. It has excellent spatial resolution without artefacts that is helpful in clearly delineating the presence of small lesions such as epidermoid cyst and its relationship with surrounding structures and increasing diagnostic certainty. Conclusion: We present a rare case of presumed third ventricular epidermoid cyst and potential role of newer MRI sequences in small intraventricular lesions.

Enhancement Pattern of the Normal Facial Nerve on Three - Dimensional (3D) - Fluid Attenuated Inversion Recovery (FLAIR) Sequence at 3.0 T MR Units

PURPOSE: To compare the enhancement pattern of normal facial nerves on 3D-FLAIR and 3D-T1-FFE-F) sequences at 3.0 T MR units. MATERIALS AND METHODS: We assessed 20 consecutive subjects without a history of facial nerve abnormalities who underwent temporal bone MRI with contrast enhancement between January 2008 and March 2009. Two neuroradiologists independently reviewed pre-/post-enhanced 3D-T1-FFE-FS and 3D-FLAIR images respectively with 2-week interval to assess the enhancement of normal facial nerves divided into five anatomical segments. The degree of enhancement in each segment was graded as none, mild or strong, and the results of 3D-FLAIR and 3D-T1-FFE-FS image sets were compared. RESULTS: On 3D-FLAIR images, one of the two reviewers observed mild enhancement of the genu segment in two (10%) subjects. On 3D-T1-FFE-FS images, at least one segment of the facial nerve was enhanced in 13 (65%) subjects. At least one reviewer found that 17 of the 100 segments showed enhancement on 3D-T1-FFE-FS images, with the mastoid segment being the most commonly enhanced. Interobserver agreement on 3D-T1-FFE-FS images was good for enhancement of the normal facial nerve (kappa= 0.589). CONCLUSION: In contrast to 3D-T1-FFE-FS, normal facial nerve segments rarely showed enhancement on 3D-FLAIR images.

Optimizations of 3D MRI Techniques in Brain by Evaluating SENSE Factors

PURPOSE: A parallel imaging method provides us to improve temporal resolution to obtain three-dimensional (3D) MR images. The objective of this study was to optimize three 3D MRI techniques by adjusting 2D SESNE factors of the parallel imaging method in phantom and human brain. MATERIALS AND METHODS: With a 3 Tesla MRI system and an 8-channel phase-array sensitivity-encoding (SENSE) coil, three 3D MRI techniques of 3D T1-weighted imaging (3D T1WI), 3D T2-weighted imaging (3D T2WI) and 3D fluid attenuated inversion recovery (3D FLAIR) imaging were optimized with adjusting SESNE factors in a water phantom and three human brains. The 2D SENSE factor was applied on the phase-encoding and the slice-encoding directions. Signal-to-noise ratio(SNR), percent signal reduction rate(%R), and contrast-to-noise ratio(CNR) were calculated by using signal intensities obtained in specific regions-of-interest (ROI). RESULTS: In the phantom study, SENSE factor=3 was provided in 0.2% reduction of signals against without using SENSE with imaging within 5 minutes for 3D T1WI. SENSE factor=2 was provided in 0.98% signal reduction against without using SENSE with imaging within 5 minutes for 3D T2WI. SENSE factor=4 was provided in 0.2% signal reduction against without using SENSE with imaging around 6 minutes for 3D FLAIR. In the human brain study, SNR and CNR were higher with SENSE factors=3 than 4 for all three imaging techniques. CONCLUSION: This study was performed to optimize 2D SENSE factors in the three 3D MRI techniques that can be scanned in clinical time limitations with minimizing SNR reductions. Without compromising SNR and CNR, the optimum 2D SENSE factors were 3 and 4, yielding the scan time of about 5 to 6 minutes. Further studies are necessary to optimize 3D MRI techniques in other areas in human body.

Visualization of endolymphatic hydrops using Magnetic Resonance Imaging after intratympanic Gd-DTPA administration in patients with Meniere's disease

BACKGROUND AND OBJECTIVES: Endolymphatic hydrops are known as major causes of Meniere's disease. MRI (Magnetic resonance imaging) with contrast tried recently makes it possible to visualize perilymphatic and endolymphatic space without invasive procedures. There are no tryouts in the interior of our country. We attempted MRI after injection of gadolinium-diethylen-triamine pentaacetic acid (Gd-DTPA) in normal adults and patients with Meniere's disease to make sure 3D-FLAIR (fluid-attenuated inversion recovery) MRI parameters and to visualize endolymphatic spaces. MATERIALS AND METHODS: Five normal adults and Five patients with Meniere's disease were included in this study. Twenty-four hours after Gd-DTPA intratympanic injection, we performed 3D-FLAIR and 3D-IR imaging at 3T. MRI region of interest signal intensity was used to determine the diffusion of Gd-DTPA into the perilymphatic fluid spaces over time. RESULTS: Five of five in normal group, using 3D-IR MRI after Gd injection, had enhanced imagings (perilymphatic spaces) of inner ears. Five of five in patients group, using 3D-IR after Gd injection, had enhanced perilymphatic spaces and non-enhanced endolymphatic hydrops. CONCLUSIONS: Delayed contrast imaging of the inner ear with 3D-IR MRI after Gd-DTPA intratympanic injection revealed in vivo visualization of endolymphatic hydrops.