Value of CT and three-dimensional reconstruction revealing specific radiological signs for screening causative high jugular bulb in patients with Meniere's disease

Characterization of jugular bulb position on computed tomography (CT) with implications for excision of vestibular schwannomas

To describe the distribution of jugular bulb position and pneumatization of posterior lip of internal auditory meatus (IAM) in patients with vestibular schwannoma (VS). This retrospective study included 43 patients who had a thin slice (< 2 mm) CT temporal bone for preoperative planning of retrosigmoid approach for excision of VS between March 2011 and March 2021. On computed tomography (CT), high riding jugular bulb was defined by its relationship to IAM and correlated with type of jugular bulb according to Manjila et al. classification. The most common position of the jugular bulb was type 2a on the side of the tumor (26/43, 60.5%) and contralateral to the side of the tumor (28/43, 65.1%). High riding jugular bulb was noted in 9 (20.9%) patients. Seven among the 9 (77.9%) patients with high riding jugular bulb had Manjila et al. type 4 jugular bulb. Pneumatization of posterior lip of IAM was noted in 8 (18.6%) patients. Avoidance of drilling of the IAM in the subgroup of 23 patients who underwent total excision of the tumor was significantly associated with Manjila et al. type 4 jugular bulb (3/4, 75%, p = 0.04) and pneumatization of posterior lip (3/4, 75%, p = 0.04). Ideally all patients with VS should undergo petrous bone CT of < 2 mm slice thickness as it can help in qualifying the jugular bulb position and recognizing pneumatization of the IAM. The presence of Manjila et al. type 4 jugular bulb or pneumatization of the posterior lip in patients with VS should alert the surgeon to anticipate and prevent complications related to drilling the posterior lip of the IAM.

ACR Appropriateness Criteria® Dizziness and Ataxia: 2023 Update

Diagnostic evaluation of a patient with dizziness or vertigo is complicated by a lack of standardized nomenclature, significant overlap in symptom descriptions, and the subjective nature of the patient's symptoms. Although dizziness is an imprecise term often used by patients to describe a feeling of being off-balance, in many cases dizziness can be subcategorized based on symptomatology as vertigo (false sense of motion or spinning), disequilibrium (imbalance with gait instability), presyncope (nearly fainting or blacking out), or lightheadedness (nonspecific). As such, current diagnostic paradigms focus on timing, triggers, and associated symptoms rather than subjective descriptions of dizziness type. Regardless, these factors complicate the selection of appropriate diagnostic imaging in patients presenting with dizziness or vertigo. This document serves to aid providers in this selection by using a framework of definable clinical variants. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

High jugular bulb in patients with non-thrombotic internal jugular venous and transverse sinus stenosis: Clues to pathogenesis

AIMS

Conventional theories for jugular bulb (JB) formation are insufficient to explain the high proportion of high JB in adult patients. We aimed to study features of high JB in patients with non-thrombotic internal jugular venous stenosis (IJVS) and/or transverse sinus stenosis (TSS) to explore the pathogenesis of high JB formation.

METHODS

We retrospectively enrolled consecutive patients with the diagnosis of non-thrombotic IJVS and/or TSS. The relationship between IJVS and/or TSS and high JB was explored. Logistic regression analysis was performed to identify potential independent risk factors for high JB.

RESULTS

A total of 228 patients were included in the final analyses. The proportions of IJVS, dominant-side IJVS, and non-TSS in dominant-side high JB subgroup were higher than those in nondominant-side high JB subgroup (83.3% vs. 62.5%, p < 0.001; 72.2% vs. 18.3%, p < 0.001; 43.5% vs. 29.2%, p = 0.02). Heights of JBs on dominant sides in IJVS subgroup and non-TSS subgroup were higher than those in non-IJVS subgroup and TSS subgroup (12.93 ± 2.57 mm vs. 11.21 ± 2.76 mm, p < 0.001; 12.66 ± 2.71 mm vs. 11.34 ± 2.73 mm, p = 0.003). Multivariate logistic regression indicated an independent association between dominant-side IJVS and dominant-side high JB (odds ratio, 29.40; 95% confidence interval, 11.04-78.30; p < 0.001).

CONCLUSION

IJVS and asymmetric transverse sinus were independently and positively associated with high JB, especially dominant-side IJVS with dominant-side high JB, indicating a potential hemodynamic relationship between IJVS and high JB formation. Conversely, TTS might impede high JB formation.

Wave In in auditory brainstem response suggests a high possibility of a high jugular bulb

Background

Wave In, which refers to the negativity between waves I and II in auditory brainstem response (ABR), is an electrophysiological phenomenon observed in previous studies. The term "high jugular bulb" (HJB) describes a jugular bulb that is located in a high position in the posterior aspect of the internal acoustic canal. The present study aimed to explore the correlation between wave In and the possibility of a HJB.

Methods

This retrospective study included a cohort of pediatric patients diagnosed with profound hearing loss who were enrolled in a government-sponsored cochlear implantation program at an academic medical center between January 2019 and December 2022. The analysis involved examining the results obtained from the ABR test and high-resolution computed tomography (HRCT) of the temporal bone in the patients. The position of the jugular bulb was classified according to the Manjila and Semaan classification.

Results

A total of 221 pediatric patients were included in the study. Twenty-four patients, with a median age of 3 years and a range of 1-7 years, showed significant bilateral (n = 21) or unilateral (n = 3) wave In (mean latency: right ear, 2.16 ms ± 0.22 ms; left ear, 2.20 ms ± 0.22 ms). The remaining 197 patients showed an absence of ABR. The HRCT images revealed that 18 of the 24 patients (75%) had HJB, but only 41 of the 197 patients who lacked ABR (20.8%) showed signs of HJB. The ratio difference was considered statistically significant based on the chi-squared test (χ2 = 32.10, p < 0.01). More than 50% of the HJBs were categorized as type 4 jugular bulbs, which are located above the inferior margin of the internal auditory canal.

Conclusion

ABR wave In in pediatric patients with profound hearing loss suggests a high possibility of HJB. The physiological mechanism underlying this correlation needs further investigation.

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.

Assessment of jugular bulb variability based on 3D surface models: quantitative measurements and surgical implications

PURPOSE

High-riding jugular bulbs (JBs) among other anatomical variations can limit surgical access during lateral skull base surgery or middle ear surgery and must be carefully assessed preoperatively. We reconstruct 3D surface models to evaluate recent JB classification systems and assess the variability in the JB and surrounding structures.

METHODS

3D surface models were reconstructed from 46 temporal bones from computed tomography scans. Two independent raters visually assessed the height of the JB in the 3D models. Distances between the round window and the JB dome were measured to evaluate the spacing of this area. Additional distances between landmarks on surrounding structures were measured and statistically analyzed to describe the anatomical variability between and within subjects.

RESULTS

The visual classification revealed that 30% of the specimens had no JB, 63% a low JB, and 7% a high-riding JB. The measured mean distance from the round window to the jugular bulb ranges between 3.22 ± 0.97 mm and 10.34 ± 1.41 mm. The distance measurement (error rate 5%) was more accurate than the visual classification (error rate 15%). The variability of the JB was higher than for the surrounding structures. No systematic laterality was found for any structure.

CONCLUSION

Qualitative analysis in 3D models can contribute to a better spatial orientation in the lateral skull base and, thereby, have important implications during planning of middle ear and lateral skull base surgery.

Proposal for a Unitary Anatomo-Clinical and Radiological Classification of Third Mobile Window Abnormalities

Introduction: An increased number of otic capsule dehiscence (OCD) variants relying on the third window pathomechanism have been reported lately. Therefore, a characterization of the anatomical structures involved and an accurate radiological description of the third window (TW) interface location have become essential for improving the diagnosis and appropriate therapeutic modalities. The purpose of this article is to propose a classification based on clinical, anatomical, and radiological data of third mobile window abnormalities (TMWA) and to discuss the alleged pathomechanism in lesser-known clinical variants.

Materials and Methods: The imaging records of 259 patients who underwent, over the last 6 years, a high-resolution CT (HRCT) of the petrosal bone for conductive hearing loss were analyzed retrospectively. Patients with degenerative, traumatic, or chronic infectious petrosal bone pathology were excluded. As cases with a clinical presentation similar to those of a TW syndrome have recently been described in the literature but without these being confirmed radiologically, we thought it necessary to be integrated in a separated branch of this classification as “CT - TMWA.” The same goes for certain intralabyrinthine pathologies also recently reported in the literature, which mimic to some extent the symptoms of a TW pathology. Therefore, we suggest to call them intralabyrinthine TW-like abnormalities.

Results: Temporal bone HRCT and, in some cases, 3T MRI of 97 patients presenting symptomatic or pauci-symptomatic, single or multiple, unilateral or bilateral OCD were used to develop this classification. According to the topography and anatomical structures involved at the site of the interface of the TW, a third-type classification of OCD is proposed.

Conclusions: A classification reuniting all types of TMWA as the one proposed in this article would allow for a better systematization and understanding of this complex pathology and possibly paves the way for innovative therapeutic approaches. To encompass all clinical and radiological variants of TMWA reported in the literature so far, TMWAs have been conventionally divided into two major subgroups: Extralabyrinthine (or “true” OCD with three subtypes) and Intralabyrinthine (in which an additional mobile window-like mechanism is highly suspected) or TMWA-like subtype. Along these subgroups, clinical forms of OCD with multiple localization (multiple OCD) and those that, despite the fact that they have obvious characteristics of OCD have a negative CT scan (or CT – TMWA), were also included.

A comparison of endolymphatic duct blockage, endolymphatic sac drainage and endolymphatic sac decompression surgery in reversing endolymphatic hydrops in Meniere's disease

Background

To explore the differences between endolymphatic duct blockage, endolymphatic sac drainage and endolymphatic sac decompression surgery in the reversal of endolymphatic hydrops (EH) in patients with intractable Meniere’s disease (MD).

Methods

A total of 27 MD patients receiving endolymphatic duct blockage surgery (n = 10), endolymphatic sac drainage surgery (n = 9) and endolymphatic sac decompression surgery (n = 8) underwent gadolinium-enhanced inner ear magnetic resonance imaging (MRI) scans prior to, 2 weeks after and at > 12 months following surgery.

Results

In the group with endolymphatic duct blockage, the second MRI revealed no changes in EH, whereas the third MRI revealed a reversal of vestibular EH in 3 patients and a downgrading of cochlear hydrops in 2 of these 3 patients, who presented with an improvement in their hearing and complete control of vertigo. In the group with endolymphatic sac drainage, the second MRI showed a reversal of EH in 4 patients, and no changes in EH in the remaining 5 patients, whereas the third MRI showed that those 4 patients who presented with a reversal of EH at the second MRI stage remained unchanged except a recurrence of vestibular hydrops in 1 patient. All 4 patients exhibited a complete control of vertigo, but hearing improved in 1, worsened in 1 and remained unchanged in 2. In the group with endolymphatic sac decompression, both the second and third MRI examination revealed no reversal of EH.

Conclusions

The present study has shown that both endolymphatic duct blockage surgery and endolymphatic sac drainage surgery have the potential to reduce EH in certain MD patients, but none of the patients receiving endolymphatic sac decompression surgery showed reversal of their EH.

Graphical Abstract

Cross-sectional Area of the Superior Petrosal Sinus is Reduced in Patients with Significant Endolymphatic Hydrops

Purpose: To evaluate the relationship between the size of the venous structures related to the inner ear and the degree of endolymphatic hydrops (EH).

Methods: Thirty-four patients with a suspicion of EH underwent whole brain MR imaging including the inner ear. Images were obtained pre- and post-administration, and at 4 and 24 hours after the intravenous administration of a gadolinium-based contrast agent (IV-GBCA). The cross-sectional areas (CSA) of the internal jugular vein (IJV), superior petrosal sinus (SPS), and inferior petrosal sinus (IPS) were measured on the magnetization prepared rapid acquisition of gradient echo (MPRAGE) images obtained immediately after the IV-GBCA. The grade of EH was determined on the hybrid of reversed image of positive endolymph signal and native image of positive perilymph signal (HYDROPS) images obtained at 4 hours after IV-GBCA as no, mild, and significant EH according to the previously proposed grading system for the cochlea and vestibule, respectively. The ipsilateral CSA was compared between groups with each level of EH grade. P < 0.05 was considered statistically significant.

Results: There were no statistically significant differences between EH grades for the CSA of the IJV or that of the IPS in either the cochlea or the vestibule. The CSA of the SPS in the groups with significant EH was significantly smaller than that in the group with no EH, for both the cochlea (P < 0.01) and the vestibule (P < 0.05). In an ROC analysis to predict significant EH, the cut-off CSA value in the SPS was 3.905 mm² for the cochlea (AUC: 0.8762, 95% confidence interval [CI]: 0.7952‒0.9572) and 3.805 mm² for the vestibule (AUC: 0.7727, 95% CI: 0.6539‒0.8916).

Conclusion: In the ears with significant EH in the cochlea or vestibule, the CSA of the ipsilateral SPS was smaller than in the ears without EH.

Dynamics in Endolymphatic Hydrops & Symptoms in Meniere's Disease After Endolymphatic Duct Blockage, Preliminary Results

Objective: The purpose of the present study was to evaluate the dynamics of endolymphatic hydrops (EH) and symptoms in a group of patients who underwent endolymphatic duct blockage (EDB) for treatment of intractable Meniere's Disease (MD), and to explore a metric for verifying the effectiveness of EDB procedure.

Methods: A total of 22 patients with intractable MD patients who underwent EDB participated in the present study. EH was visualized using locally enhanced inner ear magnetic resonance imaging (MRI) prior to and following surgery. The vestibular hydrops ratio (VHR) in the second MRI examination was compared with the pre-surgery recordings.

Results: Following EDB, 6 patients exhibited complete or partial reversal of EH, complete control of vertigo spells and reported improvement in hearing; 13 patients showed no changes in EH or hearing, but 5 of these patients exhibited complete control of vertigo attacks, and the other 8 patients exhibited improved control of vertigo attacks. The final 3 patients showed an increase in EH, but symptomatic worsening in 2 patients, and symptomatic improvement in 1 patient. There was a significant difference in the average VHR prior to and following EDB. Postoperative VHR was positively correlated with the frequency of vertigo spells in the latest 6 months of follow-up and improvement of postoperative average hearing threshold.

Conclusion: The decreased EH accompanying the reduction in vertigo attacks and hearing preservation may provide a metric for verifying the effectiveness of EDB treatment in patients with MD.