Noninvasive Quantification of Left-to-Right Shunt in Pediatric Patients (original) (raw)
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Circulation, 2004
Background— Flow quantification in real time by phase-contrast MRI (PC-MRI) may provide unique hemodynamic information in congenital heart disease, but available techniques have important limitations. We sought to validate a novel real-time magnetic resonance flow sequence in children. Methods and Results— In 14 pediatric patients (mean age 5.2±2.0 years) with cardiac left-to-right shunt, pulmonary (Q p ) and aortic (Q s ) flow rates were determined by nontriggered free-breathing real-time PC-MRI with single-shot echo-planar imaging combined with sensitivity encoding, which yielded 25 phase images per second at 2.7×2.7-mm in-plane resolution (field of view 30×34 cm 2 ). Over a 9.5-second period that included 2 to 5 respiratory cycles, 16.6±2.6 subsequent stroke volumes (range 13 to 22) were acquired in each vessel. Results were compared with conventional retrospectively ECG-gated PC-MRI. Mean Q p /Q s by conventional PC-MRI was 1.91±0.64, and it was 1.94±0.68 (mean±SD) by real-time ...
Radioangioscintigraphy and Doppler Echocardiography in the Quantification of Left-to-Right Shunt
Pediatric Cardiology, 2000
The magnitude of left-to-right shunt in 55 children with isolated congenital heart disease [atrial septal defect (ASD) or ventricular septal defect (VSD) (muscular and perimembranous)] was estimated by two methods: radionuclide quantification and Doppler echocardiography [flow (L/min) ס mean velocity × area × ejection time × heart rate]. We found little difference between the magnitude of left-to-right shunt obtained with Doppler echocardiography and that with radioangioscintigraphy for a whole group of patients (N ס 55, −11.42% to 12.04%) and for subgroups of ASD (n ס 24, −12.49% to 12.19%) and VSD (n ס 31, −10.69% to 12.23%). These results indicate that Doppler echocardiography, in comparision with radioangioscintigraphy, is sufficiently accurate for clinical estimation of the Q p /Q s ratio in isolated congenital heart disease with left-to-right shunt.
Journal of The American College of Cardiology, 1984
Range gated two-dimensional Doppler echocardiographic methods were evaluated for quantifying pulmonary (QP) to systemic (QS) blood flow ratios. Twenty-one patients were studied, 4 with patent ductus arteriosus, 6 with atrial septal defect and 11 with ventricular septal defect. The Doppler pulmonary to systemic flow (QP:QS) estimation method involved calculating volume flow (liters/min) at a variety of intracardiac sites by using imaging information for flow area and Doppler outputs to calculate mean flow velocity as a function of time. Area volume flows were combined to yield QP:QS ratios. The sites sampled were main pulmonary artery, ascending aorta, mitral valve orifice and subpulmonary right ventricular outflow tract. The overall correlation between Doppler QP:QS estimates and those obtained at cardiac catheterization (n = 18) or radionuclide angiography (n = 3) was r = 0.85 (standard error of the estimate = 0.48:1). These preliminary results suggest that clinical application of this Doppler echocardiographic method should allow noninvasive estimation of the magnitude of cardiac shunts.
Assessment of PDA shunt and systemic blood flow in newborns using cardiac MRI
2013
Patent ductus arteriosus (PDA) remains common in preterm newborns, but uncertainty over optimal management is perpetuated by clinicians' inability to quantify its true haemodynamic impact. Our aim was to develop a technique to quantify ductal shunt volume and the effect of PDA on systemic blood flow volume in neonates. Phase contrast MRI sequences were optimized to quantify left ventricular output (LVO) and blood flow in the distal superior vena cava (SVC) (below the azygos vein insertion), descending aorta (DAo) and azygos vein. Total systemic flow was measured as SVC + DAo À azygos flow. Echo measures were included and correlated to shunt volumes. 75 infants with median (range) corrected gestation 33 +6 (26 +4-38 +6) weeks were assessed. PDA was present in 15. In 60 infants without PDA, LVO matched total systemic flow (mean difference 2.06 ml/kg/min, repeatability index 13.2%). In PDA infants, ductal shunt volume was 7.9-74.2% of LVO. Multiple linear regression analysis correcting for gestational age showed that there was a significant association between ductal shunt volume and decreased upper and lower body flow (p = 0.01 and p < 0.001). However, upper body blood flow volumes were within the control group 95% confidence limits in all 15 infants with PDA, and lower body flow volumes within the control group limits in 12 infants with PDA. Echocardiographic assessment of reversed diastolic flow in the descending aorta had the strongest correlation with ductal shunt volume. We have demonstrated that quantification of shunt volume is feasible in neonates. In the presence of high volume ductal shunting the upper and lower body flow volume are somewhat reduced, but levels remain within or close to the normal range for preterm infants.
4D Flow MRI Quantification of Congenital Shunts: Comparison to Invasive Catheterization
Radiology: Cardiothoracic Imaging, 2021
To compare invasive right heart catheterization with four-dimensional (4D) flow MRI for estimating shunt fraction in patients with intracardiac and extracardiac shunts. Materials and Methods: In this retrospective study, patients who underwent 4D flow MRI and invasive right heart catheterization with a shunt run between August 2015 and November 2018 were included. The primary objective was comparison of estimated shunt fraction (ratio of pulmonary-to-systemic flow, Q p /Q s) at 4D flow and catheterization. Secondary objectives included comparison of the right ventricular-to-left ventricular stroke volume ratio (RVSV/LVSV) to shunt fraction (for those with applicable shunts) and comparison of cardiac output between 4D flow and catheterization. Statistical analysis included Pearson correlation and Bland-Altman plots. Results: A total of 33 patients met inclusion criteria (mean age, 49 years 6 16 [standard deviation]; 24 women). 4D flow measurements of Q p /Q s strongly correlated with those at catheterization (r = 0.938), and there was no bias. RVSV/LVSV correlated strongly with Q p /Q s from 4D flow (r = 0.852) and catheterization (r = 0.842). Measurements of left ventricle (Q s) and right ventricle (Q P) cardiac output from 4D flow and catheterization (Fick) correlated moderately overall (r = 0.673 [Q p ] and r = 0.750 [Q s ]). Conclusion: Shunt fraction measurement using 4D flow MRI compares well with that using invasive cardiac catheterization.
Assessment of shunt volumes in children with ventricular septal defects
Clinical Research in Cardiology, 2006
Summary The aim of this study was to compare the results of magnetic resonance based shunt volume measurements with the results of the invasive method by the principle of Fick. In 14 children (median age: 16.5 months) with ventricular septal defects the shunt volume was quantified by magnetic resonance flow measurements under spontaneous breathing conditions as well as with invasive angiography
Journal of the American College of Cardiology, 1990
In children with a ventricular seplal defect, Iransstptal blood flow has been demonstrated angiographically to be bidirectional in all but the smallest defects . To investigate this phenomenon noninvasively, two-dimensional Doppler color flow echocardiography was used in 77 patients (aged I day to 15.5 years, naean 24 months) . During isovolumelric contraction, flow was seen from the left to the right ventricle in 82 (98%) of 84 studies. During isovalumorle relaxation, right to left flow was noted in 72 (96%) of 75 studies.
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 1999
Glenn shunt and Fontan procedure, the most widely used surgical procedures in congenital heart anomalies, may be associated with abnormal pulmonary blood flow patterns and the development of pulmonary arteriovenous fistulae. This study quantified pulmonary and whole-body blood flow using the microsphere technique by sequential injection of 99mTc microspheres into upper and lower limb veins and performing planar lung imaging in four projections and anterior and posterior whole-body scans in 46 patients with either Glenn shunt or Fontan procedure. The right-to-left shunt volume was estimated by a brain and kidneys-to-lungs ratio and compared with calculations from the whole-body scans. In 31 of 46 patients, the blood from the superior vena cava was drained preferentially into the right lung (75%+/-19%). The inferior venous system was drained equally into both lungs. The right-to-left shunt volume was 24%+/-12% after injection into the superior caval system, 50%+/-18% after injection i...