Prospective MR Evaluation of Endolymphatic Hydrops at Multiple Flip Angles Using Single-Dose Gadolinium Contrast

Technical advancements in inner ear MRI promise improved diagnosis and management of Ménière disease (MD), but a key challenge in optimizing 3D-FLAIR protocols for inner ear imaging lies in selecting the optimal flip angle. This study evaluates the 3 most common flip angle parameters used in 3D-FLAIR imaging for MD through a prospective, head-to-head comparison of image quality at constant flip angle (CFA) 120^°, CFA 140^°, and variable flip angle (VFA) obtained 4 hours after IV administration of a single-dose gadolinium-based contrast agent.

We prospectively enrolled 16 consecutive patients at our institution's otology clinic on the basis of the 2015 American Academy of Otolaryngology-Head and Neck Surgery criteria for MD, including acute or fluctuating symptoms of vertigo, hearing loss, tinnitus, or aural fullness. Each patient underwent delayed inner ear MRI at 3T with the 3 most commonly used flip angles: CFA 120°, CFA 140°, and VFA. The contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR) were determined for each flip angle. Assessment of blood-labyrinthine barrier (BLB) permeability, utricle-saccule discrimination, and endolymphatic hydrops (EH) was performed by 2 head and neck neuroradiologists.

Thirty-one ears were analyzed. One ear was excluded on the basis of a prior history of left labyrinthectomy after failed medical management of MD. There were 17 symptomatic and 14 asymptomatic ears determined by clinical and hearing evaluation. The SNR of the perilymphatic space and CNR of the endolymphatic space were significantly higher at CFA 140^°, followed by CFA 120^°, and then VFA (P < .05). There was significantly improved visualization of EH, the utricle-saccule complex, and BLB permeability at CFA 140^° (P < .05), with excellent interobserver agreement (κ > 0.80).

Our study demonstrates that 3D-FLAIR inner ear imaging using CFA 140^° and single-dose IV gadolinium contrast at 3T is a reliable method for detecting EH.