Time-resolved spin-labeled balanced steady-state free precession cineangiography for visualizing intracardiac shunt:...

A time-resolved spin-labeled cineangiographic MRI technique for visualizing blood flow in the heart and defects of the atrial septum is described. The method utilizes a spin labeling preparation and a time-resolved balanced steady-state free precession imaging readout that enhances blood in the left atrium or right atrium and suppresses background signal through inversion recovery. Four volunteer studies and 10 patient studies were performed at 1.5 T to characterize the signal properties and to test the clinical feasibility of depicting atrial septal defects. In volunteers, the spin-labeled cineangiographic method depicted intracardiac blood flow patterns and demarcated the intact atrial septum. Peak target to adjacent atrial chamber contrast-to-noise ratios of 84 and 94 were obtained 758 and 689 ms postlabeling; 50% of peak contrast-to-noise ratio was maintained for 803 and 599 ms in the left atrium and right atrium, respectively. In all patients with an atrial septal defect, the spin-labeled cineangiographic method demonstrated left-to-right flow and maintained good morphological assessment of surrounding cardiac structures. Right-to-left flow was seen in three patients. In conclusion, the spin-labeled cineangiographic method displayed favorable signal properties in volunteers and demonstrated shunting in patients with atrial septal defects. The technique is expected to be a viable alternative to the few techniques available for visualizing blood flow in the heart.