Multi-sequence MRI signal intensity ratios as candidate imaging correlates for audiovestibular dysfunction in...

Vestibular schwannoma (VS) typically induces gradual sensorineural hearing impairment and vestibular dysfunction. Nevertheless, clinically applicable non-invasive candidate imaging markers capable of reflecting pathological alterations within the inner ear have not yet been well established. The present study sought to systematically investigate the correlative relationships between labyrinth signal intensity ratios acquired from multi-sequence inner ear magnetic resonance imaging (MRI) and audiovestibular functional deficits in patients diagnosed with VS.

A total of 22 patients with radiologically confirmed VS were consecutively enrolled for this retrospective observational study. All subjects received 3.0 T inner ear MRI examinations covering three pulse sequences: T2-weighted imaging (T2WI), pre-contrast three-dimensional fluid-attenuated inversion recovery (3D-FLAIR), and delayed post-contrast 3D-FLAIR acquired at the 4-h time point after gadolinium administration. Signal intensity ratios (cochlea-, vestibule-, and semicircular canal-to-brainstem; CBR, VBR, SBR) were measured and correlated with pure-tone audiometry, caloric testing, and video head impulse test (vHIT) results.

Compared to contralateral unaffected ears, affected ears exhibited significantly elevated signal ratios on both delayed post-contrast and pre-contrast 3D-FLAIR sequences (all p < 0.001), indicating blood-labyrinth barrier disruption, while T2WI ratios were significantly reduced (p < 0.001), suggesting structural alterations like increased protein content. Correlation analysis revealed that pre-contrast 3D-FLAIR CBR exhibited a moderate positive correlation with the degree of hearing loss (r = 0.582, p = 0.037), whereas T2WI SBR showed a correlation with low-frequency vestibular dysfunction assessed by caloric testing (r = 0.440, p = 0.040). In contrast, none of the evaluated MRI metrics demonstrated significant correlations with high-frequency vestibular function measured by vHIT.

These findings demonstrate that specific inner ear MRI signal ratios serve as promising candidate imaging correlates for auditory impairment and low-frequency vestibular deficits in VS. Pre-contrast 3D-FLAIR and T2WI sequences offer distinct insights into inflammatory leakage and structural damage, respectively. The potential for these metrics to guide personalized management strategies remains to be evaluated in future studies. Large-scale multicenter investigations incorporating histopathologic verification are therefore needed to dissect these underlying mechanisms and develop predictive prognostic frameworks.