Injected 3T-3D-FLAIR-MRI labyrinthine patterns match with the severity and tonotopic alteration in sudden sensorineural hearing loss.

Abstract

The aim of the study was to assess a correlation between MRI labyrinthine changes detected with IV-gadolinium optimized high-resolution 3D-FLAIR sequences 4h after injection (OPT4-3DFLAIR) and the type of SSNHL, in terms of frequency alteration and severity. This was a prospective monocentric study achieved from July 2019 to December 2020. The inclusion criterion was acute hearing loss of at least 30dB over three contiguous frequencies occurring within a 72-h period, documented by a pure-tone audiometry (PTA). The primary endpoint was the visual assessment of hyperintensity in labyrinthine structures on OPT4-3DFLAIR performed on 3T MRI. Thirty-six affected ears were included (20 men, 15 women; mean age: 54.5 ± 16.3years) with 69.4% full-spectrum hearing loss. The median hearing loss, expressed as median and interquartile range [IQR] was 91dB [74-120], with 47.2% of concomitant acute vestibular syndrome. Pathological signal was found in 26 out of 36 ears (72.2%). Basal turn enhancement was found in all abnormal MRIs, with 73.1% of apical turn enhancement and 50% of vestibular enhancement. Seventeen on 19 cases (89.5%) with apical involvement on MRI had low-frequency hearing loss. Vestibular involvement on MRI was significantly associated with a wider frequency range of hearing loss (p = 0.0002) and the severity of SSNHL (84.5 [71.7-92.5] dB versus 120 [85.8-120] dB, p = 0.0158). This report shows that in pathological MRI in SSNHL, a pathologic cochlear base signal is always detected, a cochlear apical turn enhancement matches with low-tone impairment, and a pathological signal within the posterior labyrinth is associated with an impairment of all frequencies and the severity of SSNHL.