Lower Extremity Deep Venous Thrombosis: Evaluation with Ferumoxytol-enhanced MR Imaging and Dual-Contrast Mechanism—Preliminary Experience

Abstract

Institutional review board approval and informed consent were obtained for this HIPAA-compliant study, whose purpose was to prospectively evaluate the use of a dual-contrast mechanism in conjunction with an iron oxide blood pool contrast agent, ferumoxytol, to depict deep venous thrombosis (DVT). Nine patients with lower extremity DVT detected with duplex ultrasonography (US) were imaged with magnetic resonance (MR) imaging and ferumoxytol. Three techniques, including precontrast two-dimensional time-of-flight (TOF) imaging, ferumoxytol-enhanced bright-blood imaging, and ferumoxytol-enhanced dark-blood imaging, were applied. Image quality for precontrast and ferumoxytol-enhanced images was analyzed by using a four-point scale. Thrombus was depicted as a filling defect within the blood pool on bright-blood images and as bright tissue that appeared highly contrasted against a dark background on dark-blood images. Image quality of ferumoxytol-enhanced images was uniformly superior to that of precontrast TOF images (P = .007). Compared with precontrast TOF images, ferumoxytol-enhanced bright-blood images had higher contrast-to-noise ratios (CNRs) between thrombus and blood (P = .051), whereas ferumoxytol-enhanced dark-blood images showed significantly higher CNRs between thrombus and surrounding muscle (P = .008). Ferumoxytol-enhanced MR imaging can depict DVT with a dual-contrast mechanism and show the extent of thrombus.

Advanced imaging in acute and chronic deep vein thrombosis

“…With contrast enhanced MRV unpredictable arrival of gadolinium based contrast in the more distal veins confounded by the very short transit time due to rapid redistribution into the extracellular fluid space led to development of "blood pool" contrast agent for calf veins imaging (65,66).…”

“…Li et al (66) prospectively evaluated the use of a dualcontrast mechanism in conjunction with an iron oxide blood pool contrast agent, ferumoxytol, to depict DVT. Three techniques, including precontrast 2D TOF, ferumoxytolenhanced bright-blood imaging, and ferumoxytol-enhanced dark-blood imaging, were applied focusing on its T1 as well as T2 relaxivity.…”

“…Dark-blood imaging is best for showing the extent of a thrombus and for detecting thrombi that are incompletely or not surrounded by blood (e.g., small calf thrombi) (66). Stable blood pool enhancement improves the SNR and longer imaging window allows to perform multiple sequences with no loss of image quality or diagnostic accuracy (66).…”

Blood pool contrast agents for venous magnetic resonance imaging

“…Ferumoxytol may therefore be an attractive option for patients with renal function impairment since iron-based agents are not associated with risk of nephrogenic systemic fibrosis, and can be considered in vascular imaging when gadolinium-based agents are contraindicated. In addition, Li et al evaluated extremity deep venous thrombosis with Ferumoxytol-enhanced MR and found that image quality scores for Ferumoxytolenhanced MR were uniformly superior to those of noncontrast 2D time-of-flight images (average image quality score for Ferumoxytol was 3.6 vs. 1.4 for precontrast images) (1). Also, MR showed agreement with duplex US in depicting 90% of the thrombi and an increased detection of additional contralateral thrombi.…”

“…Historically, one of the earliest imaging modalities used in venous imaging was ascending contrast venography, which is rarely used today due its invasiveness and risk of complications. Instead, ultrasound (US) has now become the modality of choice in clinical practice for the evaluation of deep vein thrombosis (DVT), with advantages in cost effectiveness, noninvasiveness, and portability in critically ill patients (1). However, key limitations of US exist, and include decreased sensitivity due to body habitus or edema, individual operator dependence (2), and difficulty in evaluation of calf veins and recurrent or chronic DVT (3).…”