The Value Of Post-contrast Delayed 3D-FLAIR MRI In The Diagnosis Of Unilateral Peripheral Vestibular Dysfunction

Background Clinically,unilateral peripheral vestibular dysfunction(UPVD)with dizziness/vertigo as the chief complaint is quite common.At present,with the application of vestibular evaluation techniques related to vertigo,such as calorie test /video head impulse test,the level of location diagnosis of peripheral vertigo,especially unilateral peripheral vestibular disease,has been greatly improved.However,it is still difficult to locate the vestibule,cochlea or vestibular nerve damage more accurately in clinic,and to diagnose the possible mechanisms such as endolymphatic hydrops(EH),blood-labyrinth barrier(BLB)damage.In recent years,intravenous injection of gadolinium(Gd)contrast agent for three-dimensional fluid-attenuated inversion recovery magnetic resonance imaging(3D-FLAIR MRI)can make more subtle lesions in labyrinthine,which provides a new means for accurate positioning of patients with UPVD and prediction of risk factors.Objective To analyze the common imaging features of post-contrast delayed 3DFLAIR MRI in UPVD patients and the predictive diagnosis of MRI positive,and further explore the correlation between imaging classification and cochleovestibular function tests and the possible influencing factors.Methods A total of 76 UPVD patients who were admitted to the outpatient and ward of the department of neurology of Beijing Aerospace Center Hospital from May2020 to June 2022 were enrolled.Clinical baseline data were collected,including age,sex,total course of disease,current course of disease,ear symptoms such as ear tightness and ear blockage and spontaneous nystagmus(SN)and other signs.Complete related cochleovestibular function tests,including pure-tone audiometry(PTA),calorie test and v HIT.All patients underwent post-contrast delayed 3D-FLAIR MRI after intravenous injection of Gd.At the same time,improve the collection of vascular risk factors indicators of patients,including hypertension,diabetes,hyperlipidemia and coronary heart disease,and related indicators of immune abnormalities,including antinuclear antibody spectrum and rheumatoid factor(RF),thyroglobulin antibodies(TGAb),thyroid peroxidase antibodies(TPOAb).Patients with UPVD were divided into MRI positive(MRI+)group and MRI negative(MRI-)group according to the abnormal imaging results.Single factor analysis was used to compare the differences of the above different clinical indexes between the two groups,and then Logistic was used.At the same time,draw the receiver operating characteristics(ROC)curve of the subjects,and its effectiveness is evaluated by the area under curve(AUC).To further analyze the correlation between cochleovestibular function tests and labyrinth imaging classification,so as to explore the possible pathophysiological mechanism of UPVD.Based on the imaging characteristics,MRI+ patients were further divided into vestibular EH group,cochlear EH group,vestibular perilymphatic enhancement(PE)group and cochlear PE group,and the differences of cochleovestibular function tests in different imaging types were analyzed to explore the disease related influencing factors.Results(1)The imaging results of UPVD patients showed that: There were 37 cases in MRI+ group and 39 cases in MRI-group,and the positive rate of MRI was 48.7%.Univariate analysis showed that the average age of MRI+ group was higher than that of MRI-group(P =0.007),and ear symptoms accounted for 78.4%(29/37)in MRI+ group and 46.2%(18/39)in MRI-group,and the proportion of patients in MRI+ group was significantly higher than that in MRIgroup(P=0.004).Vascular risk factors accounted for 54.1%(20/37)in MRI+ group and 23.1%(9/39)in MRI-group,and the proportion of patients in MRI+ group was significantly higher than that in MRI-group(P=0.005).Vascular immune abnormalities accounted for 29.7%(11/37)in MRI+ group and 10.3%(4/39)in MRI-group,and the proportion of patients in MRI+ group was significantly higher than that in MRI-group(P =0.029).The PTA in MRI+ group was significantly higher than that in MRI-group(P <0.001),and the CP value in MRI+ group was higher than that in MRI-group(P =0.029).(2)The predictive diagnosis of MRI+ in UPVD patients showed that: PTA(OR=1.096,95%CI 1.040-1.155,P=0.001)and immune abnormality(OR=7.063,95%CI 1.243-40.151,P=0.027)were independent risk factors for MRI+.And the AUC of MRI+ was 0.853(95%CI 0.757-0.950,P<0.001),when PTA > 32 d B.The AUC was 0.929(95%CI 0.872-0.986,P < 0.001)in the logistic model constructed by incorporating PTA and immune abnormalities.(3)Correlation between cochleovestibular function test and imaging classification in UPVD: the PTA of PE was significantly higher than that of vestibular EH(P=0.014)and cochlear EH(P=0.02);the CP value of vestibular PE patients was significantly higher than that of vestibular EH(P=0.002)and cochlear EH(P=0.003);the v HIT gain in vestibular PE patients was lower than that in vestibular EH(P=0.001)and cochlear EH(P=0.001),and v HIT gain in cochlear PE patients was lower than that in vestibular EH(P=0.024)and cochlear EH patients(P=0.021).The PTA of patients with vestibular EH grade 0 was significantly smaller than that of vestibular EH gradeⅠ(P<0.001)and vestibular EH grade Ⅱ(P<0.001),and the severity of vestibular EH was positively correlated with PTA(r=0.707,P<0.001).The PTA of cochlear EH grade 0 was significantly smaller than that of cochlear EH gradeⅠ(P<0.001)and cochlear EH gradeⅡ(P=0.002),and the severity of cochlear EH was positively correlated with PTA(r=0.577,P<0.001).(4)Possible mechanism of UPVD imaging classification: 42.9%(12/28)of EH patients had vascular risk factors,and 88.9%(8/9)of PE patients,and the proportion of PE patients was significantly higher than that of EH patients(P= 0.033).Univariate logistic analysis was performed on vascular risk factors,regression analysis showed that vascular risk factors were the risk factors of PE(OR=10.667,95%CI 1.171-97.185,P=0.036).Conclusions(1)Nearly half of UPVD patients have abnormal post-contrast delayed 3DFLAIR MRI,and the imaging features of post-contrast delayed 3D-FLAIR MRI in UPVD patients are mainly EH and PE.When the PTA of UPVD patients is > 32 d B and there are immune abnormalities,it is recommended to perform postcontrast delayed 3D-FLAIR MRI examination.(2)The severity of EH is positively correlated with the severity of hearing impairment.Compared with UPVD patients with EH,the cochlear and vestibular functions of UPVD patients with PE are more seriously damaged.(3)Vascular risk factors are the risk factors of PE,presumably related to the destruction of BLB caused by vascular injury mechanism.