Faculty Bibliography

PURPOSE: The purpose of this report is to describe the MR findings of aortic vegetations in two patients. METHOD: MR imaging using SE and fast GE (Fastcard) sequences was performed in the axial and coronal planes. RESULTS: The vegetations were not visible with SE MRI, but were clearly visible with fast GE imaging (Fastcard). The vegetations appeared as areas of low signal at valve leaflets in contrast to the bright flowing blood. CONCLUSION: MR evaluation in patients with infective endocarditis is useful in clarifying echocardiographic findings and establishing the diagnosis in previously undiagnosed patients

Ideal position of the buttoned device for occlusion of atrial septal defects was achieved more often with transesophageal than with transthoracic echocardiographic guidance (10/11 vs 7/23; P = 0.001). Patients with ideal device position were less likely to have residual shunts, device unbuttoning, or atrioventricular valve regurgitation (2/17 vs 11/17; P = 0.002). We therefore recommend the use of transesophageal echocardiography to guide implantation of the buttoned device. (ECHOCARDIOGRAPHY, Volume 13, March 1996)

Doppler estimation of RV dP/dt correlates well with micromanometer catheter-measured values in children with hypoplastic left heart syndrome. Doppler estimation of RV dP/dt is a method of quantifying RV systolic function independent of geometric assumptions, and may be a valuable method for longitudinal analysis of RV function

The last decade saw a dramatic change in the management of congenital heart defects. The introduction and development in echocardiography and Doppler modalities enable definitive diagnosis of congenital lesions without cardiac catheterization. At the same time, new therapeutic procedures for congenital defects using the catheter as a channel for different procedures were developed. These therapeutic procedures have replaced cardiac surgery in many types of defects. The new developments in echocardiography and Doppler modalities provide accurate imaging and visualization of the transcatheter devices and brought these two imaging modalities into a close marriage. The use of echocardiography and Doppler in the catheterization laboratory became a must, especially when used in atrial (ASD) and ventricular septal defect (VSD) closure. In this article we will detail the role of echocardiography in the different transcatheter interventional procedures in the catheterization laboratory. Those include atrial septostomy, blade atrial septectomy, balloon dilation, ASD closure, VSD closure, patent ductus anterior closure, and pericardiocentesis

We investigated whether Doppler measurement of the fetal middle cerebral artery peak systolic velocity can be used to detect fetal anemia in pregnancies complicated by maternal blood group immunization. We first studied normal values for the middle cerebral artery peak systolic velocity in 135 fetuses (Group A), and also in 23 fetuses at risk for anemia who underwent 56 cordocenteses to assess the fetal hematocrit (Group B). A test to detect fetal anemia, based on the middle cerebral artery peak systolic velocity, was developed by using the data of the fetuses of Group A and Group B. Successively, the middle cerebral artery peak systolic velocity was prospectively determined in 16 fetuses at risk for anemia who underwent 42 cordocenteses (Group C) to assess the test developed, in a multicenter prospective fashion, by using the data of Group A and Group B. In the normal fetuses an exponential model expressed the increase of the middle cerebral artery peak systolic velocity values with advancing gestation. By using the data of the fetuses of Group A and Group B, four zones of anemia risk were identified. In Group C, none of the anemic fetuses had the middle cerebral artery peak velocity below the normal mean value, whereas all of the anemic fetuses had the peak velocity above the normal mean. The middle cerebral artery blood velocity increases with advancing gestation and is a non-invasive method of detecting anemia in pregnancies complicated by maternal blood group immunization

OBJECTIVES. This study attempted to determine the site, relative size and dynamic geometry of atrial septal defects using dynamic three-dimensional echocardiography. BACKGROUND. Recent studies have demonstrated the feasibility of dynamic three-dimensional echocardiography. Images are acquired from computerized reconstruction of sequential, tomographic ultrasound 'slices' of the heart. Ultrasound images can be obtained by linear progression of a transducer within a transesophageal imaging probe. In small infants and children the large transducer size has not allowed transesophageal placement, and the probe has been placed on the thorax or in the subcostal position. Other scanning devices, housed in plastic containers, acquire images in a rotational format and can also be placed in a transthoracic or subcostal position. METHODS. Specially designed transesophageal probes and a dedicated computer unit were used for two-dimensional image retrieval and reconstruction of three-dimensional images. Sixteen patients with atrial septal defects were studied (median age 18 months, range 1 day to 18 years). In one patient, images were obtained by transesophageal probe placement; in the other 15 patients, the probe was placed in the transthoracic or subcostal position. RESULTS. A dynamic three-dimensional echocardiogram of the atrial septal defect could be obtained in 13 of the 16 patients. The distinguishing features of the atrial septal defects and their spatial orientation could be visualized in unique three-dimensional views. CONCLUSIONS. Dynamic three-dimensional imaging could be applied to the specific evaluation of atrial septal defects. Unique views of the heart allowed for spatial comprehension of the defects, rendering potentially important clinical information

Twenty physicians experienced in fetal sonographic evaluation obtained fetal nuchal skinfold thickness measurements in each of five pregnant women between 16 and 18 weeks' gestation. A random effects analysis of variance model was used to explore the sources of variation in the set of measurements, to determine the interobserver variability of sonographically measured second-trimester nuchal skinfold thickness. It was possible to obtain 96 measurements. Four measurements (all in the same patient) were deemed unobtainable due to fetal position. All recorded measurements were between 1.7 and 4.5 mm. The means (and ranges) for the five patients were 2.7 (1.7-3.6), 2.9 (2.0-4.5), 2.7 (2.0-4.0), 3.3 (2.2-4.0), and 2.7 (1.8-4.0) mm. The standard deviation for interobserver variability, caused by the combined effect of physician and machine imprecision, was 0.56 mm and the overall coefficient of variation was 19.8%. Interpatient differences were statistically significant (p = 0.004). Interphysician differences were not (p = 0.11). We conclude that experienced physician sonographers using high-resolution ultrasound equipment are able to obtain second-trimester nuchal skinfold thickness measurements within 1.1 mm of the estimated true value with 95% probability

The optimal treatment of critical aortic stenosis in the neonate and infant remains controversial. We compared transventricular dilation using normothermic cardiopulmonary bypass and percutaneous balloon aortic valvuloplasty with respect to early and late survival, relief of aortic stenosis, degree of aortic insufficiency, left ventricular function, and freedom from reintervention. Between July 1987 and July 1993, 30 neonates and infants underwent transventricular dilation or balloon aortic valvuloplasty for critical aortic stenosis. The patients in the transventricular dilation group (n = 21) ranged in age from 1 to 59 days (mean age 18.0 days +/- 19.1 days) and the balloon aortic valvuloplasty group (n = 9) from 1 to 31 days (mean age 10.0 days +/- 9.0 days). There were no significant differences in weight, body surface area, or aortic anulus diameter between the two groups (p = 1.0). Associated cardiovascular anomalies were more common in the transventricular dilation group (48%) than in the balloon aortic valvuloplasty group (11%). After intervention, the degree of residual aortic stenosis and insufficiency was equivalent in the two groups as assessed by postprocedural Doppler echocardiography. Ejection fraction improved within both groups (transventricular dilation 39% +/- 20.2% versus 47% +/- 22.0%; balloon aortic valvuloplasty 51% +/- 16.1% versus 62% +/- 8.4%), and there was no significant difference between groups. The left ventricular mass/volume ratio increased within both groups (p < 0.05) but with no significant difference between groups (transventricular dilation 1.4 +/- 0.5 gm/ml versus 1.8 +/- 0.6 gm/ml; balloon aortic valvuloplasty 1.1 +/- 0.6 gm/ml versus 1.7 +/- 0.4 gm/ml). Early mortality in the transventricular dilation group was 9.5% and in the balloon aortic valvuloplasty group, 11.1%. There was one late death in the transventricular dilation group. Four patients from the transventricular dilation group (19%) and two patients from the balloon aortic valvuloplasty group (22%) required reintervention for further relief of aortic stenosis. We conclude that both transventricular dilation and balloon aortic valvuloplasty provide adequate and equivalent relief of critical aortic stenosis. The treatment strategy adopted should depend on other factors, including associated cardiovascular anomalies, vascular access, preoperative condition, and the technical expertise available at each institution