Comparison of vestibular aqueduct visualization on computed tomography and magnetic resonance imaging in patients with Ménière's disease.

BACKGROUND: The vestibular aqueduct (VA) serves an essential role in homeostasis of the inner ear and pathogenesis of Ménière's disease (MD). The bony VA can be clearly depicted by high-resolution computed tomography (HRCT), whereas the optimal sequences and parameters for magnetic resonance imaging (MRI) are not yet established. We investigated VA characteristics and potential factors influencing MRI-VA visibility in unilateral MD patients. METHODS: One hundred patients with unilateral MD underwent MRI with three-dimensional sampling perfection with application optimized contrasts using different flip angle evolutions (3D-SPACE) sequence and HRCT evaluation. The imaging variables included MRI-VA and CT-VA visibility, CT-VA morphology and CT-peri-VA pneumatization. RESULTS: The most frequent type of MRI-VA and CT-VA visualization was invisible VA and continuous VA, respectively. The MRI-VA visibility was significantly lower than CT-VA visibility. MRI-VA visibility had a weak positive correlation with ipsilateral CT-VA visualization. For the affected side, the MRI-VA visualization was negatively correlated with the incidence of obliterated-shaped CT-VA and positively with that of tubular-shaped CT-VA. MRI-VA visualization was not affected by CT-peri-VA pneumatization. CONCLUSION: In patients with MD, the VA visualization on 3D-SPACE MRI is poorer than that observed on CT and may be affected by its osseous configuration. These findings may provide a basis for further characterization of VA demonstrated by MRI and its clinical significance.

Discrepancies of video head impulse test results in patients with idiopathic sudden sensorineural hearing loss with vertigo and vestibular neuritis.

Objective: Sudden sensorineural hearing loss with vertigo (SHLV) and vestibular neuritis (VN) remain frequent causes of acute vestibular syndrome (AVS). The aim of study was to compare the results of video head impulse test (vHIT) in patients with SHLV and VN. The characteristics of high-frequency vestibule-ocular reflex (VOR) and the differences of the pathophysiological mechanisms underlying these two AVS were explored. Methods: Fifty-seven SHLV patients and 31 VN patients were enrolled. vHIT was conducted at the initial presentation. The VOR gains and occurrence of corrective saccades (CSs) of anterior, horizontal, and posterior semicircular canals (SCCs) in two groups were analyzed. Pathological vHIT results refer to impaired VOR gains and presence of CSs. Results: In SHLV group, pathological vHIT results was most prevalent in the posterior SCC on the affected side (30/57, 52.63%), followed by horizontal (12/57, 21.05%) and anterior SCC (3/57, 5.26%). In VN group, pathological vHIT preferentially affected horizontal SCC (24/31, 77.42%), followed by anterior (10/31, 32.26%) and posterior SCC (9/31, 29.03%) on the affected side. As for anterior and horizontal SCC on the affected side, the incidences of pathological vHIT results in VN group were significantly higher than those in SHLV group (ß = 2.905, p < 0.01; ß = 2.183, p < 0.001). There were no significant differences in the incidence of pathological vHIT result in posterior SCC between two groups. Conclusion: Comparison of vHIT results in patients with SHLV and VN revealed discrepancies in the pattern of SCCs impairments, which may be explained by different pathophysiological mechanisms underlying these two vestibular disorders presenting as AVS.

Comparison of radiological abnormalities between the jugular bulb and the vestibular aqueduct in patients with Ménière's disease.

Objective: Anatomical variations of the inner ear may contribute to the development of Ménière's disease (MD), which is a complex inner ear disorder histopathologically characterized by idiopathic endolymphatic hydrops (ELH). Abnormalities of the vestibular aqueduct (VA) and the jugular bulb (JB) have been suggested as predisposing factors. Yet, few studies have investigated the correlation between JB abnormalities and VA variations as well as its clinical relevance in these patients. In this retrospective study, we investigated the differences in the incidence of radiological abnormalities of the VA and JB in patients with definite MD. Methods: Anatomical variations of JB and VA were evaluated based on high-resolution CT (HRCT) in a series of 103 patients with MD (93 unilateral cases and 10 bilateral cases). JB-related indices included JB anteroposterior and mediolateral diameter, JB height, JB type regarding to Manjila classification system, and incidences of JB diverticulum (JBD), JB related inner ear dehiscence (JBID), and inner ear adjacent JB (IAJB). VA-related indices included CT-VA visibility, CT-VA morphology (funnel, tubular, filiform, hollow, and obliterated-shaped type), and peri-VA pneumatization. Radiological indices were compared between MD ears and control ears. Results: Radiological JB abnormalities were comparable between MD ears and control ears. As for VA-related indices, the CT-VA visibility was lower in MD ears than in control ears (p = 0.004). The distribution of CT-VA morphology was significantly different between MD and control ears (p = 0.013), with a higher proportion of obliterated-shaped type in MD ears (22.1%) than in control ears (6.6%). Conclusion: Compared with JB abnormalities, the anatomical variations of VA are more likely to be an anatomically predisposing factor for MD.

Comparison between audio-vestibular findings and contrast-enhanced MRI of inner ear in patients with unilateral Ménière's disease.

Objective: The diagnosis of Ménière's disease (MD), characterized by idiopathic endolymphatic hydrops (ELH), remains a clinical priority. Many ancillary methods, including the auditory and vestibular assessments, have been developed to identify ELH. The newly emerging delayed magnetic resonance imaging (MRI) of the inner ear after intratympanic gadolinium (Gd) has been used for identifying ELH in vivo. We aimed to investigate the concordance of audio-vestibular and radiological findings in patients with unilateral MD. Methods: In this retrospective study, 70 patients with unilateral definite MD underwent three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) sequences following intratympanic application of Gd. Audio-vestibular evaluations were performed, including pure tone audiometry, electrocochleogram (ECochG), glycerol test, caloric test, cervical and ocular vestibular evoked myogenic potentials (VEMPs), and video head impulse test (vHIT). The relationship between imaging signs of ELH and audio-vestibular results was investigated. Results: The incidence of radiological ELH was higher than that of neurotological results, including the glycerol test, caloric test, VEMPs, and vHIT. Poor or slight agreement was observed between audio-vestibular findings and radiological ELH in cochlear and/or vestibular (kappa values <0.4). However, the pure tone average (PTA) in the affected side significantly correlated with the extent of both cochlear (r = 0.26795, p = 0.0249) and vestibular (r = 0.2728, p = 0.0223) hydrops. Furthermore, the degree of vestibular hydrops was also positively correlated with course duration (r = 0.2592, p = 0.0303) and glycerol test results (r = 0.3944, p = 0.0061) in the affected side. Conclusion: In the diagnosis of MD, contrast-enhanced MRI of the inner ear is advantageous in detecting ELH over the conventional audio-vestibular evaluations, which estimates more than hydropic dilation of endolymphatic space.

Radiological presence of vascular loops in the cerebellopontine angle region in patients with unilateral Ménière's disease.

OBJECTIVE: The relationship between vascular compression of the vestibulocochlear nerve and audio-vestibular symptoms remains controversial. We aimed to examine the radiological features of vascular loops signs in cerebellopontine angle (CPA) and internal auditory canal (IAC) in patients with unilateral Ménière's disease (MD). METHODS: One hundred and thirty-seven patients with unilateral definite MD and 69 control subjects (138 ears) were enrolled. All subjects received magnetic resonance imaging of CPA-IAC. The configuration of vascular loops in CPA-IAC, based on the Kazawa classification system, from MD-affected, non-affected and control ears were compared. The associations between imaging findings and Ménière's stage, electrocochleogram (EcochG) and caloric test were analyzed. RESULTS: (1) Among the MD-affected ears, 6 cases (4.4%) were classified as Kazawa type IA, 27 cases (19.7%) as IB, 60 cases (43.8%) as IIA, and 44 cases (32.1%) as IIB. No significant interaural difference in the distribution of Kazawa's types was found ([Formula: see text] = 4.737, p = 0.578) in unilateral MD patients. (2) The distribution of Kazawa's types were not significantly different between the MD-affected ears and the control subjects ([Formula: see text] = 2.876, p = 0.411). (3) No relationship was found between Kazawa staging of the MD-affected ear and Ménière's stage (H = 2.679, p = 0.444), EcochG ([Formula: see text] = 0.827, p = 0.867) and caloric test ([Formula: see text] = 4.116, p = 0.248). CONCLUSIONS: In patients with unilateral MD, the configuration of vascular loops in CPA-IAC region, measured by Kazawa criteria, did not correlate with the laterality, clinical stage, the results of EcochG and caloric test, suggesting that vascular loops may be natural anatomical variations for patients with MD.

Vascular loops in cerebellopontine angle in patients with unilateral idiopathic sudden sensorineural hearing loss: Evaluations by three radiological grading systems.

Objective: We aimed to investigate the impact of the position, configuration and neurovascular contact of the anterior inferior cerebellar artery (AICA) in cerebellopontine angle (CPA) and internal auditory canal (IAC) on the clinical features of patients with unilateral idiopathic sudden sensorineural hearing loss (ISSNHL). Methods: One hundred and thirty-six patients with unilateral ISSNHL were enrolled. All patients received detailed history inquiry and standard treatments. Pure tone audiometry and magnetic resonance imaging (MRI) of CPA-IAC were performed. The MRI findings of both ears were evaluated by the Chavda, Gorrie and Kazawa systems. The association between radiological findings and clinical data were analyzed. Results: (1) No significant interaural difference in the position, configuration and neurovascular contact of AICA was observed. (2) There was no significant association between the AICA loop and concomitant vertigo or pre-treatment audiometric configuration in the affected ear. (3) Concomitant tinnitus seemed to be affected by the configuration of AICA categorized by Kazawa system, while the Chavda and Gorrie classification of AICA loop was unassociated with tinnitus. (4) Hearing outcomes were not compromised by the position or configuration of AICA based on the Chavda and Kazawa systems. Patients with Gorrie type B tended to have better hearing recovery than those with type C. Conclusions: In patients with ISSNHL, the position, configuration and neurovascular contact of AICA in the CPA-IAC were unassociated with the side of hearing loss, audiometric configurations, or concomitant vertigo. The neurovascular contact graded by Gorrie system might be associated with hearing outcomes.

Video Head Impulse Test Findings in Patients With Benign Paroxysmal Positional Vertigo Secondary to Idiopathic Sudden Sensorineural Hearing Loss.

Benign paroxysmal positional vertigo (BPPV) is amongst the most common causes of episodic vestibular syndrome. It can be classified as idiopathic and secondary types according to the causative factors, and the underlying mechanism between idiopathic (i-BPPV) and secondary BPPV (s-BPPV) may differ. Idiopathic sudden sensorineural hearing loss (ISSNHL) has been considered as a common inner ear disease that precipitates s-BPPV. Yet, few studies have addressed the functional impairment of the semicircular canal (SCC) system in patients with s-BPPV associated with ISSNHL. Our purpose was to explore the pathophysiological mechanism and investigate the clinical implications of video head impulse test (vHIT) in these patients. Here, the clinical and laboratory data of patients with BPPV secondary to ISSNHL, including the results of vHIT, were retrospectively reviewed, and compared with those of patients with i-BPPV. Pathological vHIT findings (low vestibulo-ocular reflex gain and re-fixation saccade), which mainly affected the posterior SCC, were more common in the s-BPPV group than in the i-BPPV group (41.9 and 0%, respectively). The incidence of horizontal SCC involvement was also higher in the s-BPPV group (45.16 and 16.67%, respectively). Furthermore, patients with s-BPPV showed lower vHIT gains of the posterior and horizontal SCCs in affected ears than in unaffected ears. Compared to i-BPPV, posterior SCC paresis detected by vHIT is more prevalent in BPPV secondary to ISSNHL. This dysfunction may be associated mainly with vestibular impairments caused by ISSNHL, and not with BPPV per se.

Non-contrast MRI of Inner Ear Detected Differences of Endolymphatic Drainage System Between Vestibular Migraine and Unilateral Ménière's Disease.

Objective: We aimed to evaluate the diagnostic performance of some anatomical variables with regard to endolymphatic sac (ES) and duct (ED), measured by non-contrast three-dimensional sampling perfection with application-optimized contrasts using different flip angle evolutions (3D-SPACE) magnetic resonance imaging (MRI), in differentiating vestibular migraine (VM) from unilateral Ménière's disease (MD). Methods: In this study, 81 patients with VM, 97 patients with unilateral MD, and 50 control subjects were enrolled. The MRI-visualized parameters, such as the distance between the vertical part of the posterior semicircular canal and the posterior fossa (MRI-PP distance) and visibility of vestibular aqueduct (MRI-VA), were measured bilaterally. The diagnostic value of the MRI-PP distance and MRI-VA visibility for differentiating VM from unilateral MD was examined. Results: (1) Compared with the VM patients, patients with unilateral MD exhibited shorter MRI-PP distance and poorer MRI-VA visibility. No differences in the MRI-PP distance and MRI-VA visibility were detected between patients with VM and control subjects. (2) No significant interaural difference in the MRI-PP distance and MRI-VA visibility was observed in patients with VM and those with unilateral MD, respectively. (3) Area under the curve (AUC) showed a low diagnostic value for the MRI-PP distance and MRI-VA visibility, respectively, in differentiating between the VM and unilateral MD. Conclusions: Based on non-enhanced MRI-visualized measurement, anatomical variables with regard to the endolymphatic drainage system differed significantly between the patients with VM and those with unilateral MD. Further investigations are needed to improve the diagnostic value of these indices in differentiating VM from unilateral MD.

Ginsenoside Rb1 alleviates colitis in mice via activation of endoplasmic reticulum-resident E3 ubiquitin ligase Hrd1 signaling pathway.

Endoplasmic reticulum (ER) homeostasis is regulated by ER-resident E3 ubiquitin ligase Hrd1, which has been implicated in inflammatory bowel disease (IBD). Ginsenoside Rb1 (GRb1) is the major ginsenoside in ginseng with multiple pharmacological activities. In this study we investigated the role of Hrd1 in IBD and its regulation by GRb1. Two mouse colitis models were established to mimic human IBD: drinking water containing dextran sodium sulfate (DSS) as well as intra-colonic infusion of 2, 4, 6-trinitrobenzene sulfonic acid (TNBS). Colitis mice were treated with GRb1 (20, 40 mg·kg-1·d-1, ig) or a positive control drug sulfasalazine (500 mg·kg-1·d-1, ig) for 7 days. The model mice showed typical colitis symptoms and pathological changes in colon tissue. In addition to significant inflammatory responses and cell apoptosis in colon tissue, colon epithelial expression of Hrd1 was significantly decreased, the expression of ER stress markers GRP78, PERK, CHOP, and caspase 12 was increased, and the expression of Fas was increased (Fas was removed by Hrd1-induced ubiquitination). These changes were partially, or completely, reversed by GRb1 administration, whereas injection of Hrd1 inhibitor LS102 (50 mg·kg-1· d-1, ip, for 6 days) exacerbated colitis symptoms in colitis mice. GRb1 administration not only normalized Hrd1 expression at both the mRNA and protein levels, but also alleviated the ER stress response, Fas-related apoptosis, and other colitis symptoms. In intestinal cell line IEC-6, the expression of Hrd1 was significantly decreased by LPS treatment, but was normalized by GRb1 (200 µM). GRb1 alleviated LPS-induced ER stress and cell apoptosis in IEC-6 cells, and GRb1 action was inhibited by knockdown of Hrd1 using small interfering RNA. In summary, these results reveal a pathological role of Hrd1 in colitis, and provide a novel insight into alternative treatment of colitis using GRb1 activating Hrd1 signaling pathway.