Modalities for Imaging Two-Dimensional Imaging Cross-sectional imaging remains the gold standard for the diagnosis of structural cardiac disease during fetal life The Pediatric Council of the American Society of Echocardiography recommends obtaining multiple cross-sectional tomographic views of the heart in order to make an accurate diagnosis.15 Fetal echocardiography should include an apical four-chamber view of the heart, an apical five-chamber view, a long-axis view of the left ventricular outflow tract, a long-axis view of the right ventricular outflow tract, a short-axis view at the level of the arterial trunks, a short-axis view at the level of the ventricles, a longaxis view of the caval veins, a view of the ductal arch, and a view of the aortic arch (Table 8.1; Figs 8.1 and 8.2).15 The American Institute of Ultrasound in Medicine also recommends the three-vessel tracheal view,31 which has proven useful in the assessment of critical congenital heart disease32–35 as well as aortic arch anomalies The fetal heart rate should be documented and any arrhythmia confirmed with M-mode imaging The diameters of the orifices of all valves should be measured in systole at right angles to the plane of flow.15 Reference ranges for the diameters of all valves over the course of gestation have been published.36 Cardiac dysfunction may be assessed by cross-sectional interrogation by the presence of ascites, pleural or pericardial effusions, skin edema, and cardiomegaly as defined by a ratio of cardiothoracic areas greater than 0.36.37 A ratio of cardiothoracic areas greater than 0.6 is associated with an extremely poor outcome.38 Table 8.1 Essential Components of the Fetal Echocardiogram Feature Anatomic overview Biometric examination Cardiac imaging views/sweeps Essential Component Fetal number and position in the uterus Establish stomach position and arrangement of abdominal organs Establish cardiac position Cardiothoracic ratio Biparietal diameter Femoral length Four-chamber view Four-chamber view angled toward great arteries (five-chamber view) Doppler examination Measurements Examination of rhythm and rate Long-axis view (left ventricular outflow) Long-axis view (right ventricular outflow) Short-axis sweep, cephalad angling to include the three-vessel view Long-axis view of caval veins Ductal arch view Aortic arch view Inferior and superior caval veins Pulmonary veins Hepatic veins Venous duct Oval foramen Atrioventricular valves Arterial valves Arterial duct Transverse aortic arch Umbilical artery Umbilical vein Atrioventricular valvar diameter Arterial valvar diameter Pulmonary trunk Ascending aorta Right and left pulmonary arteries Transverse aortic arch Ventricular length Ventricular short-axis dimensions M-mode of atrial and ventricular mural motion Doppler examination of patterns of atrial and ventricular flow FIG 8.1 Tomographic planes used to image the fetal cardiovascular system Imaging planes displayed are in a normal human fetus Starting at the top left, the following views are demonstrated in a clockwise manner: 1, apical (four-chamber) view; 2, apical (five-chamber) view angled toward the aorta; 3, long-axis view of the left ventricular outflow tract; 4, long-axis view of the right ventricular outflow tract; 5, short-axis view at the level of the great vessels; 6, short-axis view with caudad angling at the level of the