Integrated backscatter of the brain of preterm infants.

We measured integrated backscatter (IBS) in the brain of preterm infants using acoustic ultrasound. The study group consisted of 25 preterm infants (gestational age, 32.4+/-2.5 weeks; birth weight, 1488+/-422 g). In parasagittal scans through the posterior horn of the lateral ventricle, regions of interest (ROI) were positioned in the cerebral white matter near the posterior horn (P), anterior horn (A) of the lateral ventricle, and the thalamus (T). IBS of the ROI was measured and IBS of P minus T (P-T) and IBS of A minus T (A-T) were calculated. A-T was greater than P-T. A-T and P-T decreased with increasing gestational age and birth weight. These changes may represent maturation of the cerebrum. A-T or P-T may be useful parameters of cerebral tissue characterization.

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.

Utility of a Doppler-derived index combining systolic and diastolic performance (Tei index) for detecting hypoxic cardiac damage in newborns.

The purpose of this study was to assess cardiac function of newborns with mild asphyxia by a Doppler-derived index combining systolic and diastolic performance (Tei index). We studied 20 preterm infants with mild asphyxia. A control group consisted of 20 gestational age-matched preterm infants without asphyxia. Echocardiograms were performed during the fourth and seventh days after birth. Peak velocities of an early filling wave (E) and an atrial contraction wave (A) were measured from the mitral inflow velocity profile and the ratio of peak E to A was calculated. Ejection time was measured from the left ventricular outflow Doppler signal. The sum of isovolumetric times was obtained by subtracting the ejection time from the interval between cessation and onset of mitral inflow. The index was the sum of isovolumetric times divided by ejection time. Ejection fraction was also calculated. The ratio of peak E to A and ejection fraction were the same in both groups. The myocardial performance index in patients with asphyxia was higher than that in patients without asphyxia. We concluded that patients with mild asphyxia have a mild cardiac dysfunction and this change can be detected by a myocardial performance index.

Efficacy of iodine-123-15-(p-iodophenyl)-3-R, S-methylpentadecanoic acid single photon emission computed tomography imaging in detecting myocardial ischemia in children with Kawasaki disease.

To evaluate its efficacy in detecting myocardial ischemia in children, iodine-123-labeled 15-(p-iodophenyl)-3-R, S-methylpentadecanoic acid (BMIPP) myocardial single photon emission computed tomography (SPECT) imaging was performed in 16 pediatric patients with Kawasaki disease (KD, 11 male, 5 female; mean age and range: 13 years 8 months and 8 years 11 months to 17 years 7 months). Five children with chest pain and no cardiac disease were studied as controls (2 male, 3 female; mean age and range: 13 years 4 months and 9 years 4 months to 17 years 11 months). Selective coronary angiography was also performed in the 16 patients to evaluate the location of coronary stenosis and coronary aneurysms. The SPECT images were expressed as polar maps (Bull's eye maps) and the 'defect' area was defined as where the uptake of BMIPP was less than the standardized BMIPP images of the 5 control children. In the 16 patients, 33 segments had coronary aneurysms and 10 (10/33: 30.3%) had significant coronary stenosis on selective coronary angiography. Nine of the 10 (90%) segments with significant coronary stenosis showed a defect on the BMIPP image whereas only 6 of the 23 (26.1%) segments without coronary stenosis showed a defect on BMIPP imaging. The sensitivity of BMIPP SPECT imaging for detection of coronary stenosis was 90% (9/10) and its specificity was 73.9% (17/23), whereas the sensitivity of (201)Tl SPECT imaging was 80% (8/10) and its specificity was 60% (14/23). There was no significant difference between the BMIPP and 201Tl SPECT images in either the sensitivity or specificity for the detection of coronary stenosis. In the present series, only one case had discordant BMIPP uptake (BMIPP uptake < (201)Tl uptake) in which there was a large coronary aneurysm and re-canalization after complete obstruction at segment 1 of the right coronary artery. This discordant BMIPP uptake reflects the possibility of ischemic but viable myocardium after re-canalization of a large aneurysm in KD. In conclusion, BMIPP SPECT imaging is useful for detecting the areas of ischemic myocardium caused by coronary artery stenosis in children with KD.

Autonomic function in Kawasaki disease with myocardial infarction: usefulness of monitoring heart rate variability.

BACKGROUND: Despite anticoagulant therapy, many patients with Kawasaki disease and giant coronary artery aneurysm develop myocardial infarction. These patients have a high risk of sudden death, but the etiology is not clear. We studied autonomic function and the possibility of malignant ventricular arrhythmia through heart rate variability. METHODS: We studied six Kawasaki disease patients with myocardial infarction and 16 normal controls. Heart rate variability was investigated using a 24 h electrocardiogram. We assessed the standard deviation from the mean of the normal R-R intervals (SDNN), the proportion of adjacent R-R intervals with a difference greater than 50 msec (pNN50) and the root-mean square of successive R-R differences as time-domain analysis (rMSSD). We assessed very low-frequency power, low-frequency power (LF), high-frequency power (HF) and the LF/HF ratio in frequency-domain analysis. RESULTS: There was no significant difference in SDNN, but there was a significant difference in pNN50 and rMSSD. Patients with Kawasaki disease showed lower HF and higher LF/HF than normal controls. CONCLUSION: Our findings suggest that patients with Kawasaki disease and myocardial infarction show decreased vagal activity, which could cause malignant arrhythmia.

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.