Volume measurement of the left ventricle in children using real-time three-dimensional echocardiography: comparison with ventriculography.

OBJECTIVES: Recently, a real-time three-dimensional echocardiography (RT3DE) volume scanning technique was developed and used clinically. For precise ventricular volumetry, independent of mathematical assumptions, imaging techniques such as three-dimensional echocardiography are required in children with heart disease. This study evaluated whether RT3DE is suitable for left ventricular volumetry in children, and whether left ventricular volumes measured by RT3DE correlate sufficiently well with those measured by left ventriculography (LVG). METHODS: Twenty-five children with heart disease, 17 boys and 8 girls aged from 8 months to 18 years (mean age 5.9 +/- 5.3 years), underwent cardiac catheterization at our institution. RT3DE was performed within 30 min after LVG using the Philips SONOS 7500 ultrasound system with an electronic sector probe consisting of a X 4 matrix phased array transducer (center frequency of 2-4 MHz). Ultrasound images of the ventricle were calculated offline using TomTec 4D Cardio-View RT 1.2 software. Left ventricular volumes by LVG were calculated using Siemens Hicor T.O.P. Finally, the left ventricular volumes by RT3DE and LVG were compared. RESULTS: Left ventricular volumes measured by RT3DE correlated and agreed well with those measured by LVG(r = 0.996, Y = 0.566 + 0.964 X, mean difference -0.29 +/- 1.90ml; left ventricular end-systolic volume, r = 0.979, Y=-0.187 + 0.897 X, mean difference -6.76 +/- 10.58ml; left ventricular end-diastolic volume). CONCLUSIONS: RT3DE is suitable for left ventricular volumetry in children. There was a good correlation between RT3DE and LVG, but the volume of left ventricular end-diastolic volume estimated by RT3DE was smaller than that by LVG.

Volume measurement of a pediatric ventricular phantom model using three-dimensional echocardiography.

PURPOSE: Volume measurement of the ventricle is necessary to evaluate cardiac function. Accurate volume measurement of the ventricle by three-dimensional (3D) echocardiography will mark a new step in pediatric cardiovascular diagnosis and treatment. We studied volume measurement of a pediatric ventricular model using 3D echocardiography. METHODS: The ultrasonic diagnostic setup used in this study comprised a Philips Sonos 7500 ultrasound system with an electronic sector probe of a ×4 matrix phased array transducer. The ventricular model was made from a latex surgical glove. The tip of the third finger of the glove was cut off and fixed to a manifold. The ventricular model was gently placed in a reservoir filled with water. Volumes of physiological saline solution ranging from 2 ml to 50 ml in 2-ml increments were injected into the ventricular model and examined. Twenty-five ultrasound images of the ventricular model were obtained using 4D Cardio View RT 1.2 software. RESULTS: There was excellent correlation and agreement between the injected volumes and the calculated volumes (Y = -0.539 + 1.005X, r = 0.997, four cut plane; Y = -0.191 + 1.006X, r = 0.997, eight cut plane). Thus, accurate volume measurement of the ventricular model by 3D echocardiography was confirmed. CONCLUSIONS: Our study demonstrated that 3D echocardiography is highly accurate for volume measurement in a pediatric ventricular model (for volumes of 2 to 50 ml) under static conditions.

Who is at risk for cardiac events in young patients with long QT syndrome?

The objective of this study was to determine who is at risk for cardiac events among young patients with long QT syndrome (LQTS) with or without a past history of LQTS-related cardiac events. The subjects were young patients with LQTS who had visited one of 36 hospitals from January 1997 to August 2000 in Japan. To predict the risk factors for cardiac events, stepwise regression analyses were performed for a total of 197 cases. There were 7 of 129 cases (5%) without a past history and 32 of the 68 (47%) cases with a past history of LQTS-related cardiac events that experienced new events after diagnosis (p<0.0001). Patients with a family history showed a higher incidence of symptoms both before and after diagnosis than patients with sporadic occurrence. Analyses revealed that noncompliance with medication and a lower age at diagnosis were significant predictors for the group with a past history. A negative predictive value <4 points was 100% in the group without a past history. To prevent future cardiac events, compliance with medication must be improved in those with a past history. A total LQTS score <4 points was useful to predict the absence of cardiac events in the group without a past history.

Effect of head position to the cerebral arterial flow in neonates.

The objective of this study is to determine the difference of the flow velocities of left and right cerebral arteries. We also studied the effect of head position to the cerebral arterial flow velocities. Eligible for inclusion in this study were 60 neonatal infants whose gestational age was 33.1+/-3.5 weeks and whose birth weight was 1793+/-613 g. The ultrasonographic examinations were performed in the first and second weeks after birth. In an axial scan through a temporal window, the Doppler sample volume was positioned at the center of the M1 portion of the middle cerebral artery and the flow velocity curve was detected. No statistical difference was seen in the flow velocities between the left and right middle cerebral arteries. However, the flow velocities in the upper side were significantly higher than those in the lower side. RI in the upper side was significantly smaller than that in the lower one. This change of flow velocities stabilized in 5 min after the head was turned upside down. The effect of head positioning to the intracranial blood flow must be considered when cerebral ultrasonography of neonates is performed.

Difference between left and right lateral ventricular sizes in neonates.

The objective of this study is to determine the causes of asymmetry of the lateral ventricles in neonates. We also studied the effect of head position and the relationship of body weight at birth in regard to lateral ventricular size. Eligible for inclusion in this study were 60 neonatal infants whose gestational age was 33.1+/-3.5 weeks and whose birth weight was 1793+/-613 g. Ultrasonographic examinations were performed at the first and the second weeks after birth. In parasagittal and coronal scans through the posterior horn of the lateral ventricle, the lateral ventricle was traced and its area was measured. We found no significant variation of ventricular size in relation to body weight at birth. The left ventricular size was larger than the right one. The difference of the left and right ventricular sizes was partially effected by head position. The ratio of left to right lateral ventricular sizes showed a very wide distribution. We considered that ventricular asymmetry is not pathological, but due to individual differences.