Application Of Prenatal MRI In The Diagnosis Of Fetal External Ear Developmental Malformation

ObjectiveTo discuss the feasibility of prenatal MRI in evaluating fetal auricle developmental malformation and atresia of external auditory canal.Compare the value of ultrasound and MRI in the fetal external ear developmental malformationMaterials and MethodsThis study was a prospective study and had been approved by our ethics committee.Twenty-three pregnant women with fetal external ear developmental malformation suspected by ultrasound examination in our hospital underwent fetal external ear MRI examination.The pregnant women were aged from 18.0 to 40.0 years old,with an average age of(30.39±5.41)years old,all of them were singleton.The gestational age ranged from 23 weeks to 35 weeks,with an average age of(26.29±3.26)weeks.The MRI sequences included half-fourier acquisition single-shot turbo spin-echo(HASTE)and true fast imaging with steady-state precession(true FISP).Each sequence consisted of axial,sagittal,and coronal images.Radiologists with experience in prenatal diagnosis scored the image quality of True FISP,HASTE and ultrasound in 46 ears of 23 fetuses,and Kappa analysis of the results was performed.Scores grading the depiction ranged from 0 to 4 and were defined as follows:4,the image quality was excellent,being optimal for the diagnosis;3,the image quality was good,meeting the general diagnostic requirements;2,the image quality was suboptimal,barely meeting the diagnostic requirements;1,the image quality was poor,not being adequate for the diagnosis;0,the auricle structure was not recognizable.Kruskal-Wallis test was used to compare the differences of True FISP,HASTE and ultrasound scores.The sensitivity,specificity and accuracy of MRI and ultrasound in the diagnosis of fetal external auditory canal were calculated and compared,using follow-up as the gold standard.Fisher exact test was used to compare the efficacy of MRI and ultrasound in diagnosing atresia of external auditory canal.ResultsTotally 23 fetuses were examined,and 27 fetal external ears with developmental malformation were confirmed by follow-up,including 27 ears with auricle malformation(3 cup-shaped auricles,24 microtia)and 23 ears with external auditory canal atresia.Among the 23 fetuses,one fetus had unilateral lower cup-shaped auricle,one fetus had bilateral cup-shaped auricle,18 fetuses had unilateral microtia(8 on the left,10 on the right),and 3 fetuses had bilateral microtia.Among them,there was one fetus of bilateral microtia with bilateral atresia of the external auditory canal combined with cleft palate.Radiologists scored the image quality of 46 fetal auricles.The True FISP sequence scores were(3.7±0.5)and(3.6±0.5),respectively,and the Kappa value was 0.815;the HASTE sequence scores were(3.3±0.6)and(3.1±0.6),respectively,and the Kappa value was 0.726.;the ultrasound scores were(2.1±0.3)and(2.1±0.3),respectively,and the Kappa value was 0.691.The results of the two readers were consistent.Kruskal-Wallis test was used to compare the differences in True FISP,HASTE and ultrasound scores.The scores of the three groups were statistically different(3.63±0.48 Vs 3.18±0.61 Vs 2.12±0.32,P<0.001).After pairwise comparison,there were differences in scores between True FISP and HASTE,True FISP and ultrasound,and HASTE and ultrasound(adjusted P values were 0.001,<0.001,and<0.001,respectively),MRI and ultrasound were correct in the diagnosis of 27 fetal auricle malformations.For the diagnosis of fetal external auditory atresia,MRI correctly diagnosed 25 cases,ultrasound correctly diagnosed 6 cases.The sensitivity,specificity and accuracy of MRI and ultrasound in the diagnosis of external auditory canal atresia were 95.7%(22/23)?75.0%(3/4)?92.6%(25/27);21.7%(5/23)?25.0%(1/4)?22.2%(6/27),respectively.The sensitivity and accuracy of MRI in the diagnosis of atresia of external auditory canal were significantly higher than those of ultrasound,with statistically significant difference(P<0.001),and the difference in specificity was not statistically significant(P=0.50).ConclusionCompared with HASTE and ultrasound,True FISP showed significant advantage in fetal auricle anatomical structure and developmental abnormalities.MRI plays an important role in the diagnosis of fetal external ear developmental malformation,which can be used as an effective supplement to ultrasound,especially for the diagnosis of external auditory atresia.