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Value of High Field MRI on Development of Human Fetal Corpus Callosum and Fetal Corpus Callosum Agenesis for US Suspected.

Author: SunJian
Tutor: MaYuXiang;LiChuanTing
School: Shandong University
Course: Medical Imaging and Nuclear Medicine
Keywords: Fetus Corpus callosum measurements Fetal corpus callosum agenesis Ultrasonography Magnetic resonance imaging
CLC: R714.5
Type: Master's thesis
Year: 2008
Downloads: 59
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Abstract

Object 1.To establish reference ranges during human pregnancy for normal fetal corpus callosum dimensions by MRI measurements and statistical analysis, facilitate a more objective diagnosis of fetal corpus callosum agenesis;2.To explore the value of MRI on corpus callosum agenesis for US suspected,comparison with the imaging manifestation and clinical value of MRI and US.Method1.Collection of 55 normal fetuses cases diagnosed by MRI during 2005-2007, gestational age from 24 to 36weeks,52 fetuses above fit for measurement of MRI, T₂-weighted MR imaging was performed using HASTE and T₁-weighted MR imaging was using FLASH.On the base of fetal brain’s anatomical structure was normal viewing by multi-plane imagine of MRI,the length of fetal corpus callosum and the anteroposterior diameter of the brain was measured at the mid-sagittal plane,the width was measured at the mid-coronal plane,then statistics analyze the outcome of the measure and calculate the ratio of the length of the corpus callosum to the anteroposterior diameter of the brain.2.After prenatal screening by US using high resolution transabdominal transducers,19 cases are fetal corpus callosum agenesis suspected,the age of pregnant women is from 20 to 37 years old（average 28 years）and with gestation from 20 to 38weeks（average 29 weeks）were studied with a 1.5 T superconductive MR unit within 24 hours.T2-weighted MR imaging was performed using HASTE and T₁-weighted MR imaging was using FLASH.Comparison with the diagnosis of MRI and Ultrasound were done with autopsy or follow-up outcome and the imaging manifestation and clinical value of MRI and US.Results1.The length and width of fetal corpus callosum show a gradual increase during pregnancy from 24 to 36weeks and increased in a linear fashion.The size of the corpus callosum as a function of gestational age was expressed by regression equations:length（mm）=-4.349+1.395×gestational age（weeks）;width（mm）= 0.744+0.244×gestational age（weeks）.The dimension-gestational age correlation coefficients were:r=0.875 for length and r=0.604 for width,these were statistically significant（P＜0.01）.The ratio of the length of the corpus callosum to the anteroposterior diameter of the brain remained relatively constant from 24 to 36 weeks’ gestation.2.Of the 19 cases,19 fetus were found,MRI confirmed 14 cases considered or suspected as fetal corpus callosum agenesis by US（8 cases are completed agenesis of corpus collosom-CACC,6 cases are partial agenesis of corpus collosom-PACC, and 5 cases had took on autopsy）,however 3 cases are mild enlargement of lateral cerebral ventricle and 2 cases are leukodystrophy.In these cases,MRI confirmed a Dandy-Walker syndrome and a lipoma of corpus callosum suspected by US,detect a Dandy-Walker syndrome and a microcephalus made missed diagnoses by US.The fetal corpus callosum and additional cerebral anomalies were shown more clearly on MR T₂-weighted images.Of the 19 cases screened by US suspected fetal corpus callosum agenesis,14 cases were confirmed by MRI and autopsy,it is thus clear that US has become a significant diagnostic method that cannot be substitute in screening fetal corpus callosum agenesis.Conclusion1.The reference ranges during human pregnancy from 24 to 36week for normal fetal corpus callosum dimensions has been established by MRI measurements and it may facilitate a more objective diagnosis of fetal corpus callosum agenesis.2.MR has advantages in displaying fetal corpus callosum agenesis over ultrasound,the quality of MR images is not affected by maternal somatotype,volume of amniotic fluid,fetal skull and the pelvic skeleton of pregnant women,and it is a valuable complement to sonography in conforming the diagnosis of fetal corpus callosum,type and additional cerebral anomalies.3.Although it has certain limitations in displaying fetal corpus callosum agenesis, the transabdominal US is still a significant method in screening fetal corpus callosum agenesis.Using MRI on the base of Ultrasonography can improve the detection rate of fetal corpus callosum agenesis,and can be applied to guide the clinical treatment timely,avoid the occurrence of birth defect and alleviate the burden of society and family.

Value of High Field MRI on Development of Human Fetal Corpus Callosum and Fetal Corpus Callosum Agenesis for US Suspected.

Abstract

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