In vivo MRI measurement of blood oxygen saturation in children with congenital heart disease.

Objective: The purpose of this prospective study was to measure in vivo blood oxygen saturation (%O2) by MRI in children with congenital heart disease (CHD) using population-based values for T2O (T2 signal decay of fully oxygenated blood) and K (a parameter representing the deoxyhemoglobin effect) and compare the %O2 with direct cardiac catheterization measurements.

Background: MRI can determine %O2 using in vivo measurement of signal decay (T2) and an in vitro calibration curve relating T2 and %O2, based on the equation: 1/T2 = 1/T2O + K(1-%O2/100)2. Recent studies have correlated the T2/%O2 in children with CHD with the adult calibration statistics.

Phase-contrast MR assessment of pulmonary venous blood flow in children with surgically repaired pulmonary veins.

Background: Pulmonary venous (PV) obstruction may complicate surgical repair of PV abnormalities. By combining phase-contrast cine (PC) imaging and contrast-enhanced angiography, magnetic resonance (MR) imaging can provide physiological information complementing anatomical diagnosis. OBJECTIVES.

Differential regurgitation in branch pulmonary arteries after repair of tetralogy of Fallot: a phase-contrast cine magnetic resonance study.

Background: The importance of pulmonary regurgitation (PR) after repair of tetralogy of Fallot (TOF) is increasingly recognized, but little is known regarding its underlying mechanisms. This phase-contrast cine magnetic resonance (PC MR) study was performed to evaluate the relative contribution of each lung to total regurgitant volume.

Methods And Results: Twenty-two patients with significant PR underwent a PC MR 3 to 16 years after repair of TOF.

Contrast-enhanced MR angiography of pulmonary venous abnormalities in children.

Background: Echocardiography and X-ray angiography have been considered as gold standards for evaluation of pulmonary venous abnormalities. However, each technique has its own limitations, such as limitation in visualization of the pulmonary veins within the lungs by echocardiography, and the invasive nature of and use of ionizing radiation in X-ray angiography. Contrast-enhanced MR angiography (MRA) is a fast noninvasive method of visualization of the vessels including the pulmonary arteries and veins.

MRI-based blood oxygen saturation measurements in infants and children with congenital heart disease.

Background: Vessel oxygen saturation can be determined with MR oximetry using an in vivo measurement of signal decay (T2) and the calibration curve relating T2 to blood oxygen saturation (%HbO(2)), where: 1/T2=1/T2O+K (1-%HbO(2)/100)(2) and K is a constant parameter which correlates with measured fibrinogen levels. The ability to noninvasively measure %HbO(2) in cardiac chambers and vessels has enormous potential in children with congenital heart disease (CHD).

Objective: The purpose of the study was to prospectively characterize the T2-%HbO(2) relationship in infants where T2-%HbO(2) is the relationship between T2 and %HbO(2) (blood oxygen saturation) expressed by the equation given above, and to determine whether adult values for K and T2O (where T2O is the T2 of fully oxygenated blood) can be extrapolated to pediatric patients with CHD.