ABSTRACT
Objective: To explore the value of speculating etiology of the magnetic resonance imaging (MRI) T1 weighted imaging (T1WI) labyrinthine high signal ratio in patients with unilateral sudden deafness accompanied by vertigo and tinnitus and its relationship with hearing prognosis. Methods: Fifty-two patients with unilateral sudden deafness accompanied by vertigo and tinnitus who were admitted to Beijing Tongren Hospital Affiliated to Capital Medical University from January 2016 to July 2019 were collected, including 27 males and 25 females, aged (47.7±15.1) years. The inner ear MRI data of 52 patients (17 plain scan, 35 enhanced scan) with unilateral sudden deafness were retrospectively analyzed. Two radiologists independently measured the labyrinthine high signal intensity of the affected side and the contralateral normal side on T1WI and enhanced T1WI and calculated the signal ratio (the normal labyrinth signal was subtracted from the affected signal and then divided by the normal signal). The etiology of the enhanced group was judged based on two methods, including whether the abnormal high signal was enhanced or not (unenhancement indicated hemorrhage and enhancement indicated inflammation), and the locations of labyrinthine involvement on enhanced three-dimensional fluid attenuated inversion recovery (3D-FLAIR) (inflammation usually involved the perilymph spaces, while hemorrhage involved the perilymph and endolymph spaces). In the plain group, the locations of labyrinthine involvement on 3D-FLAIR was applied to infer the potential etiology. Results: The two methods presumed that 8 cases might be hemorrhage (22.9%, 8/35) and 27 be inflammation (77.1%, 27/35) in the enhanced group, which had a high consistency, while it was speculated that 7 patients might be hemorrhage (7/17) and 10 patients be inflammation (10/17) in the plain group. The measurement results of the two radiologists were highly consistent within and between the groups [the intraclass correlation coefficient (ICC) values were greater than 0.800]. The area under the receiver operating characteristic (ROC) curve (AUC) of the T1WI high signal ratio in the enhanced group for speculating etiology was 0.949 (P<0.01), when the predictive threshold value was 0.467, with a sensitivity of 96.3% and a specificity of 87.5%. It might be hemorrhage when the ratio was higher than the threshold value, otherwise it was inflammation. The T1WI labyrinthine high signal ratio was higher in the hemorrhage group than that of the inflammation group, and the hearing prognosis was worse (all P<0.05). The T1WI labyrinthine high signal ratio of the unrecovered group was higher than that of the recovered group (P=0.034). Conclusions: The etiology of labyrinthine high signal formation can be inferred by quantitative values combined with the involved sites. The high signal in the labyrinth indicates poor hearing prognosis, the higher the signal intensity, the greater the possibility of hemorrhage and the worse the hearing prognosis.
