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

Jugular bulb anatomical variations and pneumatization patterns: a comprehensive CBCT analysis

PURPOSE

This study aims to assess the anatomical possibilities of the jugular bulb (JB).

METHODS

Fifty archived CBCT scans were analyzed.

RESULTS

The average distance between the internal acoustic canal (IAC) and the JB was 7.97 mm on both sides (Right: SD = 2.56 mm, range 3.16-13.3 mm; Left: SD = 2.5 mm, range 2.9-13.6 mm). JB walls' pneumatization was classified into eight patterns. Deep petrosal cells (DPCs) prevailed in the lateral wall of the JB. The absence of pneumatization (NP) was commonly found on the left side. The presence of infralabyrinthine and hypotympanic cells varied. Less common types included accessory occipital cells (AOCs), posteromedial tracts (PMTs), and basi-occipital cells (BOCs), which determined a consistent variation of the lateral wall pneumatization patterns. Pneumatization of the medial wall was not observed in 50 right sides and 49 left sides. The inferior wall analysis revealed symmetry in AOC distribution and a predominant occurrence of NP. Cases with hypotympanum (HT) in the lateral wall showed a statistically significant IAC-JB distance increase by an average of 4.67 mm compared to NPs. Specific pneumatizations, particularly HT on the lateral side, have a significant effect on the IAC-JB distance, showing a clear pattern of increasing distance from DPC to NP and then to HT. A significant distance increase in HT pneumatization was noted. There were also recorded instances of JB hypoplasia and hyperplasia, JB diverticula, dehiscent JBs, and high JBs.

CONCLUSION

This study establishes a novel classification of JB pneumatizations to aid in the understanding of the temporal bone anatomy.

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.

MRI can help differentiate Ménière's disease from other menieriform diseases

It is difficult to distinguish other pathologies mimicking Ménière's disease (MD) clinically. This study aims to investigate the differences of imaging findings and features between MD and other menieriform diseases via intravenous gadolinium-enhanced magnetic resonance imaging (MRI). 426 patients with menieriform symptoms, including MD, vestibular migraine (VM), and vestibular schwannoma (VS), underwent 3D-FLAIR and 3D-T2WI MRI 6 h after the intravenous gadolinium injection. MR images were analyzed for inner ear morphology, perilymphatic enhancement (PE), EH and other abnormalities. EH was observed at a higher rate in MD patients (85.71%) than patients with other menieriform diseases (VM group = 14.75%, VS group = 37.50%). The prevalence of unilateral EH as well as both cochlear and vestibular EH showed significant differences between MD and VM groups. The prevalence of cochlear EH (I and II) and vestibular EH (II and III) was different between MD and VM groups. The prevalence of PE was higher in MD than VM group. The degrees of cochlear and vestibular hydrops were higher in the definite than probable MD group (P < 0.05). Using these imaging features, MRI can be used to help differentiate MD from other menieriform diseases.