MR imaging of surgical complications of systemic-to-pulmonary artery shunts.

Patients with a systemic-to-pulmonary artery shunt and positive findings on traditional imaging modalities such as chest X-ray, echocardiography, or cardiac angiography often can benefit from additional noninvasive imaging with magnetic resonance imaging (MRI). Diagnostic dilemmas encountered include: pseudoaneurysms, contained fluid collection (seroma) surrounding a shunt, and stenosis of the shunt anastomoses. MRI studies using traditional cardiac-triggered spin-echo (SE) imaging and the newer breathhold MRI studies with k-space segmented gradient-recalled echo (GRE) imaging can greatly help resolve diagnostic dilemmas. By combining different MR imaging techniques it becomes possible to clearly distinguish between pseudoaneurysms and seroma, to exclude an active leak and to sometimes visualize the distal anastomosis with more precision than conventional angiography. MRI is often able to add information needed for clinical decision making prior to surgical repair.