Streaming in Transposition of the Great Arteries by Using Cardiac Magnetic Resonance Imaging

A 6-month-old child with progressive cyanosis was referred to our service for assessment. Transthoracic echocardiography confirmed the diagnosis of transposition of the great arteries, a very large ventricular septal defect (VSD), and subpulmonary stenosis. The atrial septum was intact. The transcutaneous oxygen saturation levels measured 40% to 50% in room air with a hemoglobin value of 19 g/dL. Conventional treatment with an arterial switch and VSD closure was not possible, because it would result in neoaortic obstruction because of the significant subpulmonary stenosis. Additionally, the size of the VSD was such that achieving adequate septation of the ventricles remained questionable. To aid surgical planning, a cardiac magnetic resonance scan was performed to determine whether the low transcutaneous oxygen saturation levels were due to poor mixing of blood or limited pulmonary blood flow.The scan was performed on a commercial 1.5T scanner (Achieva; Philips Healthcare, Best, The Netherlands) with a 2-channel coil. The child was awake and self-ventilating with the use of a wrap-and-feed strategy. A validated highly undersampled 4D phase-contrast flow (4D flow) sequence1 was used to …