Fetal echocardiography was introduced to clinical medicine in the early 1980s when studies reported its use for evaluation of cardiac arrhythmias as well as basic cardiac anatomy using M-mode, M-mode–directed real-time, and real-time ultrasound.1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20, and 21
Although the prenatal diagnosis of congenital heart defects was the goal of early investigators, a logical approach to the problem was not available until investigators suggested the concept of using the 4-chamber view as an initial screening tool to detect fetuses at risk for structural malformations.22,23,24,25, and 26 Although this seemed quite promising, it met with varied success.27,28,29,30,31, and 32 One of the main reasons was that not all major heart defects altered the size, shape, or anatomy of the structures identified in the 4-chamber view. Therefore, investigators suggested that examination of the outflow tracts should be considered during the screening examination of the fetal cardiovascular system.29,30,31, and 32 This suggestion was canonized when the American Institute of Ultrasound in Medicine (AIUM Practice Guideline for the Performance of an Antepartum Obstetric Ultrasound Examination, 2003), the American College of Radiology (ACR Practice Guidelines for the Performance of the Antepartum Obstetrical Ultrasound, 2003), and the American College of Obstetricians and Gynecologists (ACOG Practice Bulletin #58: Ultrasonography in Pregnancy, December 2005) published recommendations stating that an attempt should be made to examine the outflow tracts of the fetal heart during the screening examination of the low-risk fetus.
At the present time evaluation of the fetal heart still remains difficult, even though the examiner may use additional imaging modalities (M-mode, pulsed Doppler, continuous Doppler, color Doppler, and tissue Doppler).33,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83, and 84 Over 10 years ago investigators began evaluating the possibility of three-dimensional (3D) image acquisition of the fetal heart.85,86,87,88,89,90,91,92,93, and 94 During the past several years 3D and four-dimensional (4D) ultrasonography have become commercially available for use in prenatal diagnosis of heart defects.95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127,128,129,130,131,132, and 133 Because prenatal diagnosis of congenital heart defects is shared between various specialties (radiologists, obstetricians, maternal–fetal medicine specialists, and pediatric cardiologists), not all equipment and approaches may be common among diagnosticians. This communication will focus on the use of 3D and 4D sonographic approaches to examine the fetal heart whether the examiner is performing a screening examination or a fetal echocardiogram.