Color and power Doppler combined with Fetal Intelligent Navigation Echocardiography (FINE) to evaluate the fetal heart

Abstract

Objective: To evaluate the performance of color and bidirectional power Doppler ultrasound combined with Fetal Intelligent Navigation Echocardiography (FINE) in examining the fetal heart.

Methods: A prospective cohort study was conducted of fetuses in the second and third trimesters with a normal heart or with congenital heart disease (CHD). One or more spatiotemporal image correlation (STIC) volume datasets, combined with color or bidirectional power Doppler (S-flow) imaging, were acquired in the apical four-chamber view. Each successfully obtained STIC volume was evaluated by STICLoop™ to determine its appropriateness before applying the FINE method. Visualization rates for standard fetal echocardiography views using diagnostic planes and/or Virtual Intelligent Sonographer Assistance (VIS-Assistance®) were calculated for grayscale (removal of Doppler signal), color Doppler and S-flow Doppler. In four cases with CHD (one case each of tetralogy of Fallot, hypoplastic left heart and coarctation of the aorta, interrupted inferior vena cava with azygos vein continuation and asplenia, and coarctation of the aorta with tricuspid regurgitation and hydrops), the diagnostic potential of this new technology was presented.

Results: A total of 169 STIC volume datasets of the normal fetal heart (color Doppler, n = 78; S-flow Doppler, n = 91) were obtained from 37 patients. Only a single STIC volume of color Doppler and/or a single volume of S-flow Doppler per patient were analyzed using FINE. Therefore, 60 STIC volumes (color Doppler, n = 27; S-flow Doppler, n = 33) comprised the final study group. Median gestational age at sonographic examination was 23 (interquartile range, 21-27.5) weeks. Color Doppler FINE generated nine fetal echocardiography views (grayscale) using (1) diagnostic planes in 73-100% of cases, (2) VIS-Assistance in 100% of cases, and (3) a combination of diagnostic planes and/or VIS-Assistance in 100% of cases. The rate of generating successfully eight fetal echocardiography views with appropriate color and S-flow Doppler information was 89-100% and 91-100% of cases, respectively, using a combination of diagnostic planes and/or VIS-Assistance. However, the success rate for the ninth echocardiography view (i.e. superior and inferior venae cavae) was 33% and 30% for color and S-flow Doppler, respectively. In all four cases of CHD, color Doppler FINE demonstrated evidence of abnormal fetal cardiac anatomy and/or hemodynamic flow.

Conclusions: The FINE method applied to STIC volumes of normal fetal hearts acquired with color or bidirectional power Doppler information can generate successfully eight to nine standard fetal echocardiography views (via grayscale, color Doppler or power Doppler) in the second and third trimesters. In cases of CHD, color Doppler FINE demonstrates successfully abnormal anatomy and/or Doppler flow characteristics. Published 2017. This article is a U.S. Government work and is in the public domain in the USA. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Keywords: 4D; 5D heart color; STIC; cardiac; congenital heart disease; fetal echocardiography; spatiotemporal image correlation; ultrasound.

Figure 1

Color Doppler spatiotemporal image correlation volume dataset of normal fetal heart, showing nine cardiac diagnostic planes displayed automatically in single template through color Doppler Fetal Intelligent Navigation Echocardiography (see Videoclip S2). Color Doppler signals are displayed in systole. The unique feature of automatic labeling (through intelligent navigation) of each plane, anatomical structures, fetal left and right sides and cranial and caudal ends is shown. Labeling is distinctive because it stays with corresponding anatomical structures, even as image is increased in size (zoom). A, transverse aortic arch; Ao, aorta; Desc., descending; IVC, inferior vena cava; LA, left atrium; LV, left ventricle; P, pulmonary artery; PA, pulmonary artery; RA, right atrium; RV, right ventricle; RVOT, right ventricular outflow tract; S, superior vena cava; SVC, superior vena cava; Trans., transverse.

Figure 2

S‐flow Doppler (bidirectional power Doppler) spatiotemporal image correlation volume dataset of normal fetal heart, showing nine cardiac diagnostic planes displayed automatically in single template through color Doppler Fetal Intelligent Navigation Echocardiography (see Videoclip S3). Both diastolic and systolic flow is demonstrated at the same time in echocardiography views.

Figure 3

Spatiotemporal image correlation volume dataset of normal fetal heart acquired with color Doppler imaging and analyzed by color Doppler Fetal Intelligent Navigation Echocardiography (see Videoclip S4). Color display is turned off so that only grayscale information is depicted in nine cardiac diagnostic planes. The unique feature of automatic labeling (through intelligent navigation) of each plane, anatomical structures, fetal left and right sides and cranial and caudal ends is shown. A, transverse aortic arch; Ao, aorta; Desc., descending; IVC, inferior vena cava; LA, left atrium; LV, left ventricle; P, pulmonary artery; PA, pulmonary artery; RA, right atrium; RV, right ventricle; RVOT, right ventricular outflow tract; S, superior vena cava; SVC, superior vena cava; Trans., transverse.

Figure 4

Application of color Doppler Fetal Intelligent Navigation Echocardiography method in 31‐week fetus with tetralogy of Fallot (diagnostic planes with automatic labeling shown) (see Videoclip S6). Spatiotemporal image correlation volume acquired with S‐flow Doppler ultrasound. Six echocardiography views were abnormal and demonstrate typical features of this cardiac defect. Three vessels and trachea view shows narrow pulmonary artery due to stenosis, while transverse aortic arch is prominent. There is ‘Y‐shaped’ appearance of great vessels and antegrade flow (blue color) is seen. As is commonly noted in conotruncal abnormalities, four‐chamber view appeared normal, with diastolic perfusion across both atrioventricular valves (see Videoclip S6). Both five‐chamber and left ventricular outflow tract views show overriding aorta, dilated aortic root and perimembranous ventricular septal defect. Shunting of blood is seen from right ventricle across the ventricular septal defect into aortic root (five‐chamber view) and large overriding aorta (left ventricular outflow tract view). In short‐axis view of great vessels/right ventricular outflow tract, pulmonary artery is narrow with small ductus arteriosus and cross‐section of aorta is dilated. Ductal arch demonstrates similar findings. S‐flow Doppler signal was helpful in delineating anatomy of pulmonary artery and ductus arteriosus, as well as confirming antegrade flow in these structures. In aortic arch view, aortic root is dilated and there is prominent ascending aorta. A, transverse aortic arch; Ao, aorta; Desc., descending; IVC, inferior vena cava; LA, left atrium; LV, left ventricle; P, pulmonary artery; PA, pulmonary artery; RA, right atrium; RV, right ventricle; RVOT, right ventricular outflow tract; S, superior vena cava; SVC, superior vena cava; Trans., transverse.

Figure 5

Application of color Doppler Fetal Intelligent Navigation Echocardiography method in 26‐week fetus with hypoplastic left heart and coarctation of aorta (diagnostic planes with automatic labeling shown) (see Videoclip S7). Spatiotemporal image correlation volume was acquired with color Doppler ultrasound. Three vessels and trachea view shows hypoplastic transverse aortic arch with retrograde flow (red color), along with dilated pulmonary artery demonstrating antegrade flow (blue color). In four‐chamber view, left side of heart is severely hypoplastic. There is antegrade flow through tricuspid valve during diastole, but absent flow through atretic mitral valve. Five‐chamber view also demonstrates severely hypoplastic left side, antegrade flow through tricuspid valve and absence of color Doppler signal in atretic aortic root. Left ventricular outflow tract view confirms absence of color Doppler flow through mitral valve, as well as an atretic aortic valve with absent flow. However, antegrade flow is seen through the tricuspid valve. In short‐axis view of great vessels/right ventricular outflow tract, cross‐section of aorta is small when compared with pulmonary artery. There is systolic perfusion across pulmonary valve and trunk. Ductal arch view demonstrates similar findings. Aortic arch view demonstrates very narrow transverse aortic arch (coarctation), with reversed color Doppler flow in this area, as well as in the isthmus. A, transverse aortic arch; Ao, aorta; Desc., descending; IVC, inferior vena cava; LA, left atrium; LV, left ventricle; P, pulmonary artery; PA, pulmonary artery; RA, right atrium; RV, right ventricle; RVOT, right ventricular outflow tract; S, superior vena cava; SVC, superior vena cava; Trans., transverse.

Figure 6

Trivial tricuspid regurgitation in early systole demonstrated through color Doppler Fetal Intelligent Navigation Echocardiography in normal fetus (see Videoclip S10). Spatiotemporal image correlation volume was acquired with S‐flow Doppler ultrasound. Four‐chamber view diagnostic plane in grayscale was completely normal. However, S‐flow Doppler depicted tricuspid regurgitation. Automatic labeling (through intelligent navigation) of chambers in four‐chamber view and descending aorta (Ao) is shown. LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.

Figure 7

Spatiotemporal image correlation volume dataset of normal fetal heart acquired with S‐flow Doppler imaging and analyzed by color Doppler Fetal Intelligent Navigation Echocardiography (four‐chamber view with automatic labeling shown). Right inferior pulmonary vein can be visualized along imaginary straight line coursing backwards from atrial septum. Vein is seen with color flow towards left atrium (red color), at site of atrial septum (see Videoclip S11). Ao, aorta; LA, left atrium; LV, left ventricle; RA, right atrium; RV, right ventricle.

Figure 8

‘Pseudo’ ventricular septal defect (VSD) in left ventricular outflow tract view, as depicted by color Doppler. This spatiotemporal image correlation volume dataset of normal fetal heart was acquired with color Doppler imaging and analyzed by color Doppler Fetal Intelligent Navigation Echocardiography. (a) Diagnostic plane shows color signal (blue) from right ventricle crossing over anterior wall of aorta and spilling into left ventricular outflow tract, giving ‘Y’ appearance. (b) After Virtual Intelligent Sonographer Assistance was activated, automatic navigational movements improved echocardiography view and pseudo‐VSD was no longer visualized. No settings (e.g. color threshold, balance) were changed between (a) and (b).