L W Lange

Qualitative real-time cross-sectional echocardiographic imaging of the human fetus during the second half of pregnancy.

In this study, we used high-resolution echocardiographic systems to investigate how early in pregnancy normal fetal cardiac anatomy could be noninvasively evaluated. Over a 2-year period, 84 of 88 fetuses were successfully imaged (27 were studied serially). Postnatal images of 73 were obtained during the newborn period. Estimated fetal age varied at initial examination from 19-41 weeks (mean 31 ± 0.5 weeks [± SEMI) of pregnancy. Estimated fetal weight using an ultrasound algorithm varied from 500-3100 g (mean 1580 ± 80 g [± SEMI). To evaluate fetal cardiac anatomy, we reproduced commonly used cross-sectional views of the heart. The four-chamber and the short-axis great artery views have been most successful for cardiac evaluation in the fetus. These views could be obtained in 96% and 95% of the patients, respectively. With these views, cardiac chamber and valve structures, as well as two great arteries, could be imaged in detail. The ascending and descending aorta, as well as the aortic arch and vessels to the arms and head, were visualized in 87% of examinations, and the inferior and superior venae cavae were visualized in 76%. In two of three RH fetuses, changes in cardiac chambers compatible with hydrops fetalis were demonstrated. We examined all fetuses after birth and verified clinically (or noninvasively) that no cardiac malformations were present. It appears, however, that the diagnosis of major congenital heart defects should be possible before birth.

Subxiphoid cross-sectional echocardiography in infants and children with congenital heart disease.

We developed anatomically related cross-sectional echocardiographic views to image the heart from the subxiphoid area in 100 children and infants with various forms of congenital heart disease studied prospectively before cardiac catheterization. Wide-angle cross-sectional views were achieved using a mechanical sector scanner in a scan plane oriented parallel to a line between the patients shoulders (a coronal plane) showing the equivalent anatomy of an anteroposterior angiogram. The subxiphoid technique appeared to be better than chest wall-based imaging in demonstrating obstructive lesions in the proximal portion of the right ventricular outflow tract (19 patients), i.e., the subpulmonic area, which is often at the narrow edge of the sector and behind the transducer artifact in chest wall studies. The subxiphoid technique was also useful for imaging the interatrial and interventricular septae; in subxiphoid views, as opposed to four-chamber apical views, there was significantly less false septal dropout and atrial septal defects (19 patients) as well as ventricular septal aneurysms (seven patients) were easily imaged. Finally, the subxiphoid orientation provided more adequate imaging in patients with discrete diaphragmatic subaortic stenosis (four patients), even when the diaphragm was just beneath the aortic valve. Subxiphoid cross-sectional echocardiography is an easily understood anatomical format for imaging cross-sectional anatomy in congenital heart disease and is a valuable adjunct to cross-sectional echocardiography from the chest wall.

A new technique for noninvasive evaluation of femoral arterial and venous anatomy before and after percutaneous cardiac catheterization in children and infants

A new ultrasonic method was applied to image the femoral artery and vein in children for evaluation of short- and long-term effects of cardiac catheterization with femoral percutaneous cannulation. Sixty-six children and infants (aged 5 days to 20 years) were studied with a 9 megahertz electronically focused real time scanner. Adequate studies were obtained in 46 patients before catheterization, in 26 of 30 short-term follow-up studies and in 14 long-term follow-up studies. Femoral arterial size could be quantitatively measured at the inguinal ligament and a correlation existed between imaged femoral arterial diameter and body weight (r = +0.82) or body surface area (r = +0.80). Short-term follow-up ultrasonic imaging studies allowed diagnosis of spasm and other complications of percutaneous femoral arterial puncture. Long-term follow-up studies were performed 4 months to 3 years after catheterization in 14 patients who had no complications recorded at the time of catheterization. These revealed significant differences between vessels on the catheterized and uncatheterized (control) sides in only 3 of the 14. High resolution ultrasonic imaging can provide anatomic and functional information about femoral arteries and veins and appears to be of assistance in planning cardiac catheterization and in studying the short- and long-term effects of percutaneous femoral cannulation.

Noninvasive assessment of surgical systemic to pulmonary artery shunts by range-gated pulsed Doppler echocardiography

Suprasternal range-gated pulsed Doppler echocardiography was used to evaluate surgical shunt patency in children with cyanotic congenital heart disease and right ventricular outflow obstruction following systemic artery to pulmonary artery anastomoses. Normal patients had laminar Doppler auditory signals and time interval histogram flow patterns because right pulmonary artery turbulence was not present during systole or diastole. Patients with pulmonary valvar stenosis had turbulence during systole only. In all nine postoperative patients with surgical shunts, turbulent systolic and diastolic time interval histograms and abnormal auditory signals were present. A typical shunt murmur was not audible to auscultation in six of the postsurgical patients at the time of the study. Suprasternal range-gated pulsed Doppler echocardiography affords an accurate, safe and simple noninvasive bedside means for confirming shunt patency in patients who have undergone surgical systemic artery to pulmonary artery anastomoses.

Cross-sectional echocardiography in hypoplastic left ventricle: Echocardiographic—angiographic—anatomic correlations

SummaryAlthough M-mode echocardiography has become a valuable tool in the noninvasive diagnosis of hypoplastic left ventricle (HLV), it may not resolve all diagnostic uncertainty. This study compares the findings of M-mode echocardiography, cross-sectional echocardiography, and autopsy in a group of 20 infants with HLV. M-mode echocardiograms alone were obtained in eight infants; five of these children underwent cardiac catheterization, and six underwent autopsy. Cross-sectional echocardiograms were obtained in the remaining 12 infants; two of these underwent cardiac catheterization, and all 12 underwent autopsy. Cross-sectional examinations were performed with either a high-resolution mechanical sector scanner or a sequentially scanning linear array. Short-axis views were used for left ventricular size and shape and for aortic root, pulmonary artery, and ductus size; suprasternal notch views were used for imaging the aortic arch and subxiphoid views for the atrial cavities. In all 12 infants the findings from cross-sectional echocardiography closely matched those of autopsy with respect to degree of hypoplasia of the mitral valve, the left ventricular cavity, and the left ventricular outflow tract. If the diameter of a valve orifice exceeded 3 mm at autopsy, patency of the valve could be diagnosed from the cross-sectional echocardiogram. The findings when M-mode echocardiograms alone were done less closely matched the autopsy findings, and in five of the eight cardiac catheterization was judged necessary to resolve remaining diagnostic uncertainty. This study found that cross-sectional echocardiography provided an accurate noninvasive diagnosis of the spectrum of anatomy found in HLV and had fewer pitfalls than M-mode echocardiography.

Ultrasound Cardiac Diagnosis

The principles of diagnostic ultrasound and various types of echo instrumentation and usage are presented. Three lesions (patent ductus arteriosus, aortic stenosis, and transposition of the great vessels) are discussed to illustrate the application of various echo techniques and instruments.