sodium-pertechnetate-tc-99m and Ductus-Arteriosus--Patent

A simple algorithm is developed to enhance the resolution of components of multimodal pulmonary radiohistograms. Based on the assessed right ventricular ejection fraction (RVEF), it deconvolves out the effect of indicator smearing in the right ventricle on the heart rate samples of the pulmonary radiohistogram, ck. The output is the ideal curve, c'k = ck/RVEF--(1-RVEF).ck-1/RVEF, that would be obtained if RVEF equalled unity. Since the formula is not a recursive one, it does not suffer from error propagation pertinent to numerical deconvolution. Once RVEF is known, implementation of the algorithm is simple. If RVEF is not known accurately it may be replaced with its upper estimate, RVEFup > RVEF, yielding a partial deconvolution of the curve. When applied to studies of patients with left-to-right shunt the method improves the accuracy and lessens the interobserver variation of the Maltz-Treves method.

Topics: Adult; Algorithms; Child; Ductus Arteriosus, Patent; Female; Heart Septal Defects; Humans; Lung; Male; Middle Aged; Sodium Pertechnetate Tc 99m; Stroke Volume; Ventriculography, First-Pass

With first-pass radionuclide angiography, it is possible to visualize sequentially the cardiovascular structures and to obtain computer-generated time-activity curves for regions of interest over these structures. Analysis of these curves permits the detection, localization, and quantitation of intracardiac shunts and shunts between the great arteries. The authors present the formulae used for the quantitative analysis and discuss clinical applications.

Topics: Ductus Arteriosus, Patent; Electrocardiography; Heart Defects, Congenital; Heart Septal Defects, Atrial; Heart Septal Defects, Ventricular; Hemodynamics; Humans; Infant; Infant, Newborn; Models, Cardiovascular; Postoperative Complications; Radionuclide Imaging; Sodium Pertechnetate Tc 99m; Tetralogy of Fallot; Transposition of Great Vessels