MRI Measurement Of Fetal Cardiothoracic Ratio In Middle And Late Pregnancy And Its Clinical Significance

Part 1 MRI measurement of normal fetal cardiothoracic ratio in middle and late pregnancyObjective:To measure the cardiothoracic diameters and ratios of normal fetuses in middle and late pregnancy by MRI,and to establish the normal reference ranges.Methods:A total of 160 cases of normal fetuses in middle and late pregnancy who underwent MRI examination in the First Central Hospital of Baoding and the Second Hospital of Hebei Medical University form march 2016 to march2018 were selected.Four MRI sequences including single shot-fast spin echo(SS-FSE)sequence or Single shot TSE sequence,fast imaging employing steady-state acquisition(FIESTA)sequence or Balance FFE sequence,fast inversion recovery motion insensitive(FIRM)sequence or SSh-T1W-TFE sequence and diffusion weighted imaging(DWI)sequence were used to observe the imaging clarity of the heart and its surrounding structures.On FIESTA(Balance FFE)sequence,a good four-chamber view was achieved,the heart transverse diameter(HTD)?thoracic transverse diameter(TTD)?heart area(HA)?thoracic area(TA)were measured,the cardiothoracic transverse diameter ratio(CTDR)and cardiothoracic area ratio(CTAR)were calculated.The normal reference range of cardiothoracic diameters and ratios in middle and late pregnancy were obtained.The differences of measurement parameters between the middle and late pregnancy were compared.Results:1.Both FIESTA(Balance FFE)sequence and SS-FSE(Single shot TSE)sequence could clearly display fetal chest cavity structure,the lung showed hyperintensity signal.FIESTA(Balance FFE)sequence could display heart internal anatomy,the blood flow in the chamber showed slightly hyperintensity signal,the myocardial tissue and the ventricular septum showed low signal;SS-FSE(Single shot TSE)and DWI sequence,the lung showed slightly hyperintensity signal,the chamber showed low signal,the cardiac structure could not be identified.FIRM(SSh-T1W-TFE)sequence,the lung and the chamber showed low signal,could not identify the structure of thoracic cavity clearly.2.In middle pregnancy,the 95%medical reference ranges of HTD?TTD?CTDR?HA?TA?CTAR were 1.71-2.81cm?3.94-6.02cm?0.41-0.49?3.40-9.12cm~2?11.90-28.10cm~2?0.27-0.35.In late pregnancy,the 95%medical reference ranges of HTD?TTD?CTDR?HA?TA?CTAR were1.71-2.81cm?3.94-6.02cm?0.41-0.49?3.40-9.12cm~2?11.90-28.10cm~2?0.27-0.35.3.The HTD?TTD?HA?TA showed significant differences between two groups(P<0.05),whereas no significant differences were found for CTDR and CTAR(P>0.05).Conclusion:1.The FIESTA(Balance FFE)sequence can clearly display the structure of the heart and the lung tissue in the thoracic cavity,and quantitatively measure the cardiothoracic diameter and the ratio.2.The establishment of MRI's normal reference value range for cardiothoracic diameters and ratios provide reference basis for the diagnosis of fetus with abnormal cardiothoracic ratio,which has great value.Part 2 Prenatal MRI diagnosis of abnormal cardiothoracic ratio in fetuses without congenital heart diseaseObjective:To explore the value of MRI in the diagnosis of fetal abnormal cardiothoracic diameter ratio(CTDR)without congenital heart disease,the MRI images of 45 cases with abnormal CTDR were analyzed retrospectively.Methods:A total of 45 cases of abnormal fetuses who underwent MRI examination in the First Central Hospital of Baoding and the Second Hospital of Hebei Medical University form march 2016 to march 2018 were retrospectively analyzed.22 cases with CTDR-increased and 23 cases with CTDR-reduced.The MRI features of fetuses with abnormal CTDR were analyzed.Results:1.Among the 23 CTDR-reduced fetuses,there were 16 cases of congenital cystic adenomatoid malformation,6 cases of congenital diaphragmatic hernia,and 1 case of congenital high airway obstruction syndrome,with CTDR of 0.38(0.37,0.39).2.Among the 22 CTDR-increased fetuses,there were 4 cases of vein of Galen aneurysmal malformation,4 cases of infantile hepatic hemangioendothelioma,6 cases of meconium peritonitis,4 cases of intestinal obstruction and 4 cases of simple amniotic fluid increase,with CTDR of0.52(0.50,0.53).Conclusion:MRI have great contribution in diagnosis of abnormal CTR in fetus without congenital heart disease,and provide more comprehensive clinical information.