Enhancement of the Lymphatic System Following Intravenous Administration of Ferumoxytol

Lymphatic Imaging is increasingly important in the management of patients with Congenital Heart Disease. It is not known how the intravenous contrast agent ferumoxytol influences this imaging. This retrospective review of 120 patients suggests that intravenously given ferumoxytol rapidly enters the lymphatic system. The resultant shortening of T2 relaxation causes a degradation in T-2 weighted lymphangiography. Conversely, T1-weighted angiography shows clear depiction of the thoracic lymphatic duct immediately after ferumoxytol infusion. This enhancement depends on fasting status of the patient. The classic mechanism of macrophage uptake of iron oxide for MR lymphangiography does not explain the timing of these findings.