Fetal Myocardial Wall Area: Constructing a Reference Range by Means of Spatiotemporal Image Correlation in the Rendering Mode

Abstract

Objective: To establish the reference range of the myocardial wall area in the fetus using three-dimensional ultrasound in the rendering mode. Methods: A prospective, cross-sectional study including 371 singleton, uncomplicated pregnancies at 20 weeks 0 day to 33 weeks 6 days of gestation was carried out. Cardiac volumes were obtained using spatiotemporal image correlation (STIC) at the level of the four-chamber view. The end-diastolic myocardial area of the both ventricles was measured manually. The intraclass correlation coefficient (ICC) was used to assess intra- and interobserver concordance. Results: The mean myocardial area of the fetal right ventricular (RV) wall ranged from 0.86 ± 0.23 cm² at 20 weeks 0 day to 2.75 ± 0.69 cm² at 33 weeks 6 days of gestation. The mean myocardial area of the fetal left ventricular (LV) wall ranged from 0.82 ± 0.20 cm² at 20 weeks 0 day to 2.49 ± 0.59 cm² at 33 weeks 6 days of gestation. In addition, intra- and interobserver concordance for the myocardial area of the RV and LV walls was good, with ICC values of 0.94, 0.95, 0.85, and 0.93, respectively. Conclusions: The reference range for the myocardial area of the RV and LV walls was determined by cardio-STIC in the rendering mode at 20 weeks 0 day to 33 weeks 6 days of gestation, with good concordance between values.

Fetal Heart Function by Tricuspid Annular Plane Systolic Excursion and Ventricular Shortening Fraction Using STIC M-Mode: Reference Ranges and Validation

“…Because of these limitations, our group established 33 weeks and 6 days as the superior limit for studies with STIC. [34][35][36] STIC mimics one single cardiac cycle such that in fetuses with normal cardiac conduction, a single cardiac cycle represents the real fetal heart rhythm, which is reproduced on the screen. As the fetal heart 3D volumes are not subject to interference of fetal movements or maternal breathing, we believe that the intraobserver variability represents the real TAPSE variability measurement.…”

Evaluation of fetal heart geometry during pregnancy by three‐dimensional ultrasound using the STIC rendering mode

“…We defined the 20th week as the lower GA limit because starting in this period, organ growth, and weight gain in the fetus affect the final weight and proper growth . The upper limit was defined as 34th week because after this period, the fetus position on the back and imaging artifacts from the ribs are more common, hampering or even preventing the adequate analysis of the 4D fetal heart volume …”

“…We observed moderate/good intra‐ and inter‐observer reproducibility in the measurement of the eight angles of the fetal heart, proving that the STIC rendering mode is feasible and requires a learning curve. STIC rendering has been used to calculate the area of many fetal cardiac structures, including the interventricular septum, ventricular myocardium, annulus of the atrioventricular valves, and papillary muscles, and these measurements presented good intra and inter‐observer reproducibility …”

“…STIC rendering with a low level of transparency can be applied to the fetal heart using the interface between the cardiac cavities and walls, allowing improved cardiac imaging compared with two‐dimensional (2D) ultrasound . In addition, STIC rendering has been applied to measure the areas of the annulus of the atrioventricular valves, intraventricular septum, papillary muscles of the atrioventricular valves, and myocardium of the fetal heart ventricles …”

4D fetal echocardiography—An update

“…From the STIC acquisition, three‐dimensional voxels were created that had an X, Y, and Z component, resulting in three simultaneously displayed images referred to as the A, B, and C planes (Figure ). Following the first publication describing the STIC technique, numerous studies have been reported describing the use of this technique for evaluation of fetal cardiovascular structures and function …”