Iterative Denoising Accelerated 3D FLAIR Sequence for Hydrops MR Imaging at 3T.

BACKGROUND AND PURPOSE: 3D FLAIR sequences have become the criterion standard for identifying endolymphatic hydrops, but scan time remains an important limitation to their widespread use. Our purpose was to evaluate the diagnostic performance and image quality of an accelerated 3D FLAIR sequence combined with an iterative denoising algorithm. MATERIALS AND METHODS: This was a retrospective study performed on 30 patients with clinical suspicion of endolymphatic hydrops who underwent 3T MR imaging 4 hours after gadolinium injection using two 3D FLAIR sequences. The first (conventional FLAIR) was accelerated with a conventional turbo factor of 187. The second was accelerated with an increased turbo factor of 263, resulting in a 33% scan time reduction (5 minutes 36 seconds versus 8 minutes 15 seconds, respectively). A sequence was reconstructed in-line immediately after the accelerated 3D FLAIR acquisition from the same raw data with iterative denoising (accelerated-FLAIR iterative denoising). The signal intensity ratio image quality score and endolymphatic hydrops diagnosis were evaluated. RESULTS: The mean signal intensity ratio for symptomatic and asymptomatic ears of accelerated-FLAIR iterative denoising was significantly higher than the mean SNR of conventional FLAIR (29.5 versus 19 and 25.9 versus 16.3, P < .001). Compared with the conventional FLAIR sequence, the image-quality score was higher with accelerated-FLAIR iterative denoising (mean image-quality score, 3.8 [SD, 0.4] versus 3.3 [SD, 0.6] for accelerated-FLAIR iterative denoising and conventional FLAIR, respectively, P = .003). There was no significant difference in the diagnosis of endolymphatic hydrops between the 2 sequences. Interreader agreement was good-to-excellent. CONCLUSIONS: The iterative denoising algorithm applied to an accelerated 3D FLAIR sequence for exploration of endolymphatic hydrops enabled significantly reducing the scan time without compromising image quality and diagnostic performance.

MRI evaluation of the endolymphatic space in otosclerosis and correlation with clinical findings.

PURPOSE: The purpose of this study was to investigate the clinical features of ears with otosclerosis and their correlation with endolymphatic hydrops and blood-labyrinth barrier (BLB) impairment on 3T magnetic resonance imaging (MRI). MATERIALS AND METHODS: This was a single-center retrospective imaging study. Thirty-nine ears from 29 patients (17 men, 12 women; mean age 52±12 [SD] years; range 27-74 years) with non-operated otosclerosis were included. All patients underwent three-dimensional fluid attenuated inversion recovery (FLAIR) MRI sequences performed 4hours after the intravenous administration of a single dose of gadolinium-based contrast material. MRI examinations were analyzed by two radiologists for the presence of saccular hydrops (SH) and BLB impairment. Results of MRI examinations were compared with clinical findings, hearing levels and extent of otosclerotic lesions based on high-resolution computed tomography findings. BLB impairment was evaluated using the signal intensity ratio, ratio of intensities between the basal turn of the cochlea and the medulla. RESULTS: SH was observed in 1/39 (3%) otosclerotic ears and BLB impairment in 8/39 (21%) while 8/29 patients with otosclerosis (28%) had vertigo. No significant associations were found between SH or BLB impairment on MRI, and the presence of vertigo or the degree of sensorineural hearing loss. CONCLUSION: Clinical manifestations of otosclerosis (sensorineural hearing loss and rotatory vertigo) were not significantly associated with MRI findings such as BLB impairment and endolymphatic hydrops. SH was only observed in one patient with obstruction of the vestibular aqueduct by an otosclerotic focus.

Comparison of Enhancement of the Vestibular Perilymph between Variable and Constant Flip Angle-Delayed 3D-FLAIR Sequences in Menière Disease.

BACKGROUND AND PURPOSE: Endolymphatic hydrops in patients with Menière disease relies on delayed postcontrast 3D-FLAIR sequences. The purpose of this study was to compare the degree of perilymphatic enhancement and the detection rate of endolymphatic hydrops using constant and variable flip angles sequences. MATERIALS AND METHODS: This was a retrospective study performed in 16 patients with Menière disease who underwent 3T MR imaging 4 hours after gadolinium injection using two 3D-FLAIR sequences with a constant flip angle at 140° for the first and a heavily-T2 variable flip angle for the second. The signal intensity ratio was measured using the ROI method. We graded endolymphatic hydrops and evaluated the cochlear blood-labyrinth barrier impairment. RESULTS: Both for symptomatic and asymptomatic ears, the median signal intensity ratio was significantly higher with the constant flip angle than with the heavily-T2 variable flip angle (7.16 versus 1.54 and 7.00 versus 1.45, P < .001). Cochlear blood-labyrinth barrier impairment was observed in 4/18 symptomatic ears with the heavily-T2 variable flip angle versus 8/19 with constant flip angle sequences. With heavily-T2 variable flip angle sequences, endolymphatic hydrops was observed in 7-10/19 symptomatic ears versus 12/19 ears with constant flip angle sequences. We found a significant association between the clinical symptomatology and the presence of endolymphatic hydrops with constant flip angle but not with heavily-T2 variable flip angle sequences. Interreader agreement was always perfect with constant flip angle sequences while it was fair-to-moderate with heavily-T2 variable flip angle sequences. CONCLUSIONS: 3D-FLAIR constant flip angle sequences provide a higher signal intensity ratio and are superior to heavily-T2 variable flip angle sequences in reliably evaluating the cochlear blood-labyrinth barrier impairment and the endolymphatic space.

Postoperative MR imaging features after superior semicircular canal plugging in Minor syndrome.

PURPOSE: To report the postoperative magnetic resonance imaging (MRI) features after superior semicircular canal plugging in patients with Minor syndrome. MATERIALS AND METHODS: The MRI examinations with 3D T2-weighted SPACE sequence of 12 patients with superior semicircular canal dehiscence syndrome (SCDS) were retrospectively assessed. Two radiologists independently evaluated the presence of a filling defect of the superior semicircular canal above the superior ampulla and the common crus using an oblique plane parallel to the superior semicircular canal (Pöschl's plane). RESULTS: Postoperative MRI showed a filling defect above the ampulla of the superior semicircular canal and the common crus in 8/12 patients (67%). Three patients (3/12; 25%) had a filling defect involving also the superior ampulla that caused postoperative labyrinthitis with labyrinthine enhancement on MRI in 2 patients. One patient (1/12; 8%) had incomplete plugging of superior semicircular canal with abnormal functional tests and remaining symptoms. CONCLUSION: Postoperative MRI shows a normal plugging aspect of the superior semicircular canal in 67% of patients. MRI can reveal complications that may have therapeutic implications.

New mouse model for inducing and evaluating unilateral vestibular deafferentation syndrome.

BACKGROUND: Unilateral vestibular deafferentation syndrome (uVDS) holds a particular place in the vestibular pathology domain. Due to its suddenness, the violence of its symptoms that often result in emergency hospitalization, and its associated original neurophysiological properties, this syndrome is a major source of questioning for the otoneurology community. Also, its putative pathogenic causes remain to be determined. There is currently a strong medical need for the development of targeted and effective countermeasures to improve the therapeutic management of uVDS. NEW METHODS: The present study reports the development of a new mouse model for inducing and evaluating uVDS. Both the method for generating controlled excitotoxic-type peripheral vestibular damages, through transtympanic administration of the glutamate receptors agonist kainate (TTK), and the procedure for evaluating the ensuing clinical signs are detailed. COMPARISON WITH EXISTING METHODS: Through extensive analysis of the clinical symptoms characteristics, this new animal model provides the opportunity to better follow the temporal evolution of various uVDS specific symptoms, while better appreciating the different phases that composed this syndrome. RESULTS: The uVDS evoked in the TTK mouse model displays two main phases distinguishable by their kinetics and amplitudes. Several parameters of the altered vestibular behaviour mimic those observed in the human syndrome. CONCLUSION: This new murine model brings concrete information about how uVDS develops and how it affects global behaviour. In addition, it opens new opportunity to decipher the etiopathological substrate of this pathology by authorizing the use of genetically modified mouse models.

Comparison of Video Head Impulse Test and Caloric Reflex Test in advanced unilateral definite Menière's disease.

AIMS: There have been very few studies of the Video Head Impulse Test (VHIT) in patients with Menière's Disease (MD). Some reported 100% normal VHIT results, others not. These discrepancies may be due to differences in severity. The present study compared VHIT and caloric reflex test results in advanced unilateral definite MD. MATERIAL AND METHOD: A prospective study included 37 consecutive patients, with a mean age of 56±12 years. Mean hearing loss was 59±18dB HL; 12 patients were subject to Tumarkin's otolithic crises. Abnormal caloric reflex was defined as ≥20% deficit, and abnormal VHIT as presence of saccades or <0.64 gain in vertical semicircular canals and <0.78 in horizontal canals. RESULTS: All patients had normal VHIT results, and 3 had normal caloric reflex; mean caloric reflex deficit was 45%. CONCLUSION: The present study is the only one to use the August 2015 updated definition of MD. The results showed that, outside of episodes of crisis, VHIT was normal during advanced unilateral definite MD, in contrast to abnormal caloric reflex. This feature could help distinguish MD from other inner ear diseases, and it would be interesting to try to confirm this hypothesis by studying MD patients.

Evolution of age at diagnosis of congenital hearing impairment.

AIM OF THE STUDY: To show the evolution of age at diagnosis of bilateral congenital hearing impairment according to date of birth and severity of hearing loss assessed in the better ear. PATIENTS AND METHODS: Retrospective study of children with hearing aids, born or living in France and examined in the ENT department for diagnosis or follow-up of congenital hearing impairment. RESULTS: In profound deafness, median age at diagnosis fell from 50 months for children born between 1985 and 1989 to 12 months for children born between 2000 and 2004; in severe hearing impairment, from 38 to 30 months, respectively; and in moderate hearing impairment, from 85 to 40 months, respectively. DISCUSSION: In this as in other series, age at diagnosis of bilateral congenital hearing impairment is seen to be decreasing slowly. CONCLUSION: In this study of children born before 2005 (i.e., before the start of the universal neonatal hearing screening program in the Paris region of France), age at diagnosis of moderate, severe or profound bilateral congenital hearing impairment remains high for the last period studied, but has fallen significantly over the last 20 years.