Evaluation of intracardiac shunts with cardiac magnetic resonance.

Intracardiac shunts including atrial septal defect, ventricular septal defect, endocardial cushion defects, and surgical baffles may be identified, localized, and quantified using cardiac MRI methods. Both dark-blood and bright-blood techniques are helpful to identify anatomy. Contrast enhancement is especially useful for identifying associated vascular anomalies. Dynamic first-pass contrast agent signal-time studies may demonstrate rapid recirculation and shunting. Volumetric and phase contrast cine methods are useful to quantify flow. Pulmonary to systemic (Qp/Qs) flow ratios may be calculated noninvasively by comparing the pulmonary artery flow to the aortic flow measurement.