Application Of Mri In The Classic Types Of Fetal Holoprosencephaly

Objective To investigate the value of MRI in the diagnosis of classic types of fetal holoprosencephaly(HPE).Methods From December 2015 to December 2019,we performed prenatal fetal ultrasonography in our hospital and performed fetal cranial MRI within 72 hours,and 21 cases of fetal cases were diagnosed as classic HPE by prenatal ultrasound and concurrent fetal MRI.The age of pregnant women was 17 to 37 years,with an average of 26.4 ± 5.2 years,and the gestational age was 21 to 35 weeks,with an average of 26.4 ± 5.2 weeks.MRI was performed within 72 hours after US examination,using 2D FIESTA and SSFSE to scan the fetal brain in coronal,sagittal and axial position.According to the classification method proposed by DeMyer,fetuses were divided into three groups: lobar HPE(14 cases),semilobar HPE(6 cases)and alobar HPE type(1 case).The clinical data(such as age,gestational age,etc.)and MRI data(septum pellucida,lateral ventricles,deep gray nuclei,dorsal cysts and other facial deformities,etc.)of each group were observed.The frequency of different types of HPE involving deep brain structures(including the thalamus,hypothalamus,mesencephalon,callosum,caudate nucleus and lenticula)was analyzed;Using the scoring method put forward by Griffiths in 2016,we scored different types of HPE,and analyzed the differences of various types of HPE scores.Results1.Clinical data 21 cases of fetal HPE were included in this study.According toDeMyer’s classification,there were three groups: 1 case(4.7%)of alobar HPE,6 cases(28.6%)of semilobar HPE,and 14 cases(66.7%)of lobar HPE.Pregnant women range in age from 17 to 37 years.The mean age is 26.4 ± 5.2 years,of which 25.5 ± 5.5 years for lobar type,27.2 ± 3.7 years for semilobar type and 35 years for alobar type.And the gestational age range from 21 to 35 weeks.The average is 26.3 ± 4.4 weeks,including 27.4 ± 4.6 weeks for lobar type,24.7 ± 2.9 weeks for semilobar type and 21 weeks for alobar type.2.MRI morphological data In 21 cases of HPE,1 case is diagnosed as alobar HPE,,prenatal MRI showed absence of septum pellucidum,bilateral ventricle fusion,deep gray matter nucleus fusion,presence of the dorsal cyst,combined with ocular hypotelorism and proboscis;6 cases were diagnosed as semilobar HPE,Prenatal MRI showed bilateral ventricular fusion,absence frontal horn of lateral ventricle,and fusion of deep gray matter nuclei in different degrees;14 cases were diagnosed as lobar HPE,prenatal MRI showed bilateral ventricular fusion,some cases with frontal horn abnormalities,and some thalamic and hypothalamic fusion.In 21 cases of fetal holoprosencephaly,there was 1 case with hypotelorism and proboscis.3.Involvement of deep brain structures In the 21 cases of HPE included in the study,the frequency of involvement of deep brain structures was arranged from high to low as follows: thalamus 66.7%(14 / 21),corpus callosum 66.7%(14 / 21),midbrain 42.9%(9 / 21),caudate nucleus 28.6%(6 / 21),lentiform nucleus 28.6%(6 / 21),hypothalamus 28.6%(6 /21).4.MRI scoring data Among the 21 cases of HPE included in the study,4(66.7%)were lobar HPE,6(28.6)were semilobar HPE and 4.7% were alobar HPE.According to Griffiths’ scoring method,the mean scores of HPE 1.9 ± 0.8 for lobar HPE,11.17 ± 1.3 for semilobar HPE and 19 for alobar HPE,respectively.Conclusion1.In terms of clinical data,in this study,HPE fetuses were mostly examined at 20-25 gestational weeks,and the pregnant women were mostly 25-30 years old;The most common HPE is lobar HPE.2.In terms of MRI morphology,the classic type of HPE has characteristic MRI features,which is helpful for the prenatal diagnosis of HPE.3.In classic HPE fetuses,the thalamic and corpus callosum structures are most susceptible;compared to lobar HPE,semilobar HPE is more likely to involve anterior hemisphere fissure,anterior cerebral sickle,hypothalamus,midbrain,caudate nucleus,Bean-shaped nuclei and other structures.4.In fetal MRI,Griffiths score is very important for prenatal diagnosis of lobar and hemilobar HPE,and it can quantitatively evaluate the involvement of brain structure.The higher the score,the more serious the abnormal degree of brain structure.