Ventricular septal defect: visualization of shunt flow and determination of shunt size by cine MR imaging.

Cine MR imaging is a new, fast technique that employs low flip angles, short repetition and echo times, and gradient-refocused echoes. This technique was used in three patients with documented ventricular septal defects (VSDs) to obtain transverse and oblique sections of the heart spanning the cardiac cycle. In all patients, cine MR imaging showed high-velocity turbulent blood flow across the defect as areas of low signal intensity extending from the left ventricle to the right ventricle. In the oblique sections oriented parallel to the interventricular septum it was possible to identify the cross-sectional area of the VSD. Quantification of the left-to-right shunt was performed by comparing left and right ventricular stroke volumes determined from end-diastolic and end-systolic volumes of both ventricles. Cine MR imaging provides important functional information and anatomic detail in patients with VSD and may be useful for diagnosis, determination of severity, and noninvasive monitoring of the disease.