Anaiysis Of Lateral Ventricular Volume And The Calcarine Sulcus Depth In Fetuses With Ventriculomegaly By MRI

Objectives:To investigate the reliability of 3D magnetic resonance hydrography（MRH）for lateral ventricular volume measurement in fetuses with ventriculomegaly（VM）and normal lateral ventricles,using manual multi-section planimetry（MSP）as a reference standard.To quantify changes in the lateral ventricular volume,the depth of the calcarine sulcus（CS）,and Apparent diffusion coefficient（ADC）values of occipital lobe in fetuses with isolated mild ventriculomegaly（IMVM）using MRI.Methods:71 fetuses with IMVM at 24–38 gestational weeks（GA）and 58 fetuses with normal lateral ventricles at 24–38 GA were enrolled.Volumes of the lateral ventricles were measured by manual MSP and 3D MRH.Depths of the CS and ADC values were also evaluated.Agreement between the 2 methods was assessed by Bland–Altman analysis.Bivariate correlations were performed using Pearson’s method.All differences were tested by t test.Intra-and inter-rater reliability was calculated using Intra-and inter-rater correlation coefficients（ICC）.Results:There were highly significant relationships between all 3D MRH and manual MSP measurements of lateral ventricular volumes(r_VM=0.92–0.98;r_N=0.95–0.98;all p<0.0001;VM:VM group,N:normal group),although left,right and total lateral ventricular volumes measured by 3D MRH tended to be slightly larger than MSP(bias_VMM 0.1±0.95,0.26±0.63,and 0.3±0.68 mL,respectively;bias_N 0.18±0.95,0.15±0.63,and0.33±0.68 mL,respectively).Inter-rater agreement and intra-rater repeatability were also excellent for 3D MRH(ICC_VM=0.994–0.99,ICC _N=0.989–0.992;ICC_VM=0.975–0.987,ICC_N=0.958–0.971,respectively).3D MRH showed significantly reduced measuring time（VM:3.55±0.42vs.11.81±0.13 mins;N:3.08±0.39 vs.12.12±0.11 mins;all p<0.0001）.Fetuses with IMVM had significantly larger lateral ventricular volumes and smaller CS depths than controls（volumes:9.37±2.20 mL vs.5.04±1.33mL,respectively,P<0.001;depths:8.27±2.55 mm vs.10.30±3.14mm,respectively,P<0.001）.In IMVM cases,the CS depths were smaller on the side with the larger ventricle（8.10±2.54 mm vs.9.59±2.81 mm,P<0.001）.No differences were observed in occipital lobe ADC values between the two groups（IMVM=1.80±0.24μm²/ms;controls=1.78±0.28μm²/ms,P>0.05）.Conclusion:Lateral ventricular volume measurement by 3D MRH was comparable to manual MSP.Fetuses with IMVM had larger lateral ventricular volumes,shallower CS depths,but normal occipital lobe ADC values.