RESUMO
BACKGROUND: Heart defects are the most common congenital malformations in fetuses. Fetal cardiac structure and function abnormalities lead to changes in ventricular volume. As ventricular volume is an important index for evaluating fetal cardiovascular development, an effective and reliable method for measuring fetal ventricular volume and cardiac function is necessary for accurate ultrasonic diagnosis and effective clinical treatment. The new intelligent spatiotemporal image correlation (iSTIC) technology acquires high-resolution volumetric images. In this study, the iSTIC technique was used to measure right ventricular volume and to evaluate right ventricular systolic function to provide a more accurate and convenient evaluation of fetal heart function. AIM: To investigate the value of iSTIC in evaluating right ventricular volume and systolic function in normal fetuses. METHODS: Between October 2014 and September 2015, a total of 123 pregnant women received prenatal ultrasound examinations in our hospital. iSTIC technology was used to acquire the entire fetal cardiac volume with off-line analysis using QLAB software. Cardiac systolic and diastolic phases were defined by opening of the atrioventricular valve and the subsequent closure of the atrioventricular valve. The volumetric data of the two phases were measured by manual tracking and summation of multiple slices and recording of the right ventricular end-systolic volume and the right ventricular end-diastolic volume. The data were used to calculate the right stroke volume, the right cardiac output, and the right ejection fraction. The correlations of changes between the above-mentioned indices and gestational age were analyzed. The right ventricular volumes of 30 randomly selected cases were measured twice by the same sonographer, and the intra-observer agreement measurements were calculated. RESULTS: Among the 123 normal fetuses, the mean right ventricular end-diastolic volume increased from 0.99 ± 0.34 mL at 22 wk gestation to 3.69 ± 0.36 mL at 35+6 wk gestation. The mean right ventricular end-systolic volume increased from 0.43 ± 0.18 mL at 22 wk gestation to 1.36 ± 0.22 mL at 35+6 wk gestation. The mean right stroke volume increased from 0.62 ± 0.29 mL at 22 wk gestation to 2.33 ± 0.18 mL at 35+6 wk gestation. The mean right cardiac output increased from 92.23 ± 40.67 mL/min at 22 wk gestation to 335.83 ± 32.75 mL/min at 35+6 wk gestation. Right ventricular end-diastolic volume, right ventricular end-systolic volume, right stroke volume, and right cardiac output all increased with gestational age and the correlations were linear (P < 0.01). Right ejection fraction had no apparent correlation with gestational age (P > 0.05). CONCLUSION: Fetal right ventricular volume can be quantitatively measured using iSTIC technology with relative ease and high repeatability. iSTIC technology is expected to provide a new method for clinical evaluation of fetal cardiac function.
RESUMO
Objective To evaluate the concordance of two-dimensional echocardiography (2DE) and intelligent spatiotemporal image correlation (iSTIC) in measuring fetal aortic and aortic arch diameters during the second and third trimesters.Methods Data were collected by a prospective cross-sectional study of 140 normal singleton fetuses with the gestational age from 22 to 32 weeks.A total of 6 dimensions of the fetal aortic and aortic arch,including aortic annular diameter (AO),ascending aorta diameter (AAO),aortic arch diameter [AO Arch (INA to LCCA)],aortic arch diameter [AO Arch (LCCA to LSA)],aortic isthmus diameter and descending aorta diameter (DAO),were measured by two different methods.Concordance was assessed by comparing the measurements acquired by iSTIC with those determined by 2DE and depicted by Bland-Altman plots.Inter-and intra-observer variability was evaluated by the intraclass correlation coefficient (ICC) test.Results A total of 137 iSTIC volumes in 140 cases were found to be suitable for further analysis.Good correlation was observed in the measurements that determined by 2D or iSTIC (Pearson's R2 =0.977-0.983).There was no significant difference in the mean values of all the parameters that measured by two methods.Bland-Altman plot showed that the 95％ limits of agreement (LOA) in AO,AAO,AO Arch (INA to LCCA),AO Arch (LCCA to LSA),aortic isthmus diameter and DAO were (-0.1260/+ 0.2299),(-0.1707/+ 0.2241),(-0.1547/+ 0.2190),(-0.1736/+ 0.2024),(-0.1514/+ 0.2039) and (-0.1485/+ 0.2228),respectively.The points in the outside of LOA were 5.11％ (7/137),4.38％ (6/137),5.11％ (7/137),5.84％ (8/137),4.38％ (6/137)and 4.38％ (6/137),respectively.Conclusions iSTIC has a good agreement with 2DE in measuring fetal aortic and aortic arch dimensions during the second and third trimesters.