Extracardiac applications of MR blood pool contrast agent in children

Abstract

Magnetic resonance (MR) angiography has significantly reduced the need for diagnostic conventional angiography and is preferred over CT angiography in children because of its lack of ionizing radiation. The availability of gadofosveset trisodium (the only clinically approved blood pool MR contrast agent) has led to an increase in applications of MR for vascular imaging and an improvement in diagnostic quality of MR angiography. Gadofosveset is a gadolinium-based contrast agent that binds reversibly to albumin, resulting in increased paramagnetic effect and longer intravascular residence. This allows for high-resolution arterial and venous MR angiography, assessment of flow characteristics of vascular malformations, dynamic vascular imaging, and multi-station imaging with a single low-dose gadolinium contrast injection. The purpose of this pictorial essay is to facilitate understanding of the kinetics and safety profile of gadofosveset trisodium, discuss technical aspects of imaging, and illustrate advantages and extracardiac applications in pediatric body imaging.

Blood pool contrast agents for venous magnetic resonance imaging

“…Of note, QTc prolongation has been reported following gadofosveset administration, and therefore patients should be assessed for a history of underlying conditions that may predispose to arrhythmias from QTc prolongation. The most feared adverse effect of gadoliniumbased contrast agents, nephrogenic systemic fibrosis (NSF), has not been reported with gadofosveset (15).…”

“…Also, the combination of dynamic and steady-state imaging with gadofosveset allows for evaluation of anatomical and flow characteristics of vascular malformations, allowing the differentiation between high-flow and low-flow vascular malformation. First-pass images delineate the arterial anatomy and steady-state images facilitate assessment of the venous anatomy and enhancement pattern of the lesion (15).…”

“…Following the arterial first- pass phase, these agents are distributed to the extracellular compartment and rapidly diffuse out of the blood pool into the interstitium which results in a decrease in vascular signal and increased background enhancement (poor contrast-to-noise ratio) and a limited acquisition window. This short intravascular retention limits the application of dynamic imaging to evaluate flow patterns and requires repeated contrast administration to evaluate multiple stations or the effect of provocative maneuvers (15). Adequate bolus timing and patient cooperation are thus essential to obtain adequate MR angiographic images with these agents (15).…”

“…This short intravascular retention limits the application of dynamic imaging to evaluate flow patterns and requires repeated contrast administration to evaluate multiple stations or the effect of provocative maneuvers (15). Adequate bolus timing and patient cooperation are thus essential to obtain adequate MR angiographic images with these agents (15). While non contrast maging techniques are limited in detecting slow flow in smaller veins, contrast enhanced venous imaging with extracellular gadoliniumbased agents is technically more challenging than arterial imaging due to unpredictable venous opacification as contrast bolus traverses from the blood pool to interstial space (15).…”

“…Adequate bolus timing and patient cooperation are thus essential to obtain adequate MR angiographic images with these agents (15). While non contrast maging techniques are limited in detecting slow flow in smaller veins, contrast enhanced venous imaging with extracellular gadoliniumbased agents is technically more challenging than arterial imaging due to unpredictable venous opacification as contrast bolus traverses from the blood pool to interstial space (15). Gadolinium-based blood-pool contrast agents (BPCA) are characterized by prolonged intravascular circulation.…”