Ferumoxytol was selectively taken up by atherosclerotic plaques compared to non-plaque vessel walls (ΔR2* 24.6 vs 7.5 s−1; p=0.004), but did not correlate with 18F-FDG uptake.
Observational (n=13)
Can ferumoxytol-enhanced MRI quantify arterial wall inflammation in patients with carotid artery stenosis compared to healthy controls?
Ferumoxytol is selectively taken up by atherosclerotic plaques and can be used for carotid USPIO-MRI to visualize plaque inflammation, which does not correlate with 18F-FDG uptake.
Absolute Event Rate: 24.6% vs 7.5%
p-value: p=0.004
Background and aimsInflammation in atherosclerotic plaques is an important determinant of plaque vulnerability, and can be detected non-invasively using ultra-small superparamagnetic iron-oxide (USPIO) enhanced MRI. The aims of the current study were: 1) to determine whether ferumoxytol can be used for USPIO-MRI of atherosclerotic plaques, 2) to establish a protocol for quantitative USPIO-MRI of carotid artery plaques using ferumoxytol, and 3) to study the relation between USPIO uptake and plaque burden and 18F-fluorodeoxyglucose (FDG) uptake (measured by 18F-FDG PET/CT scan) in atherosclerotic plaques.MethodsIn 9 patients with carotid artery stenosis >30% and 4 healthy controls, quantitative R2* MRI scans of the carotid arteries were performed before and 72 h after USPIO administration (4 mg/kg ferumoxytol). USPIO uptake was assessed by quantifying the difference in R2* (ΔR2*) between baseline and post-USPIO scans. In addition to MRI, 18F-FDG PET/CT was performed on both carotid arteries. MR and PET/CT images were co-registered, and 18F-FDG uptake was quantified in all slices containing atherosclerotic plaque.ResultsInfusion of ferumoxytol resulted in higher R2* values after 72 h in atherosclerotic plaques (ΔR2* 24.6 ± 19.8 s−1; p = 0.0003), but not in the healthy control vessel wall (ΔR2* 2.6 ± 5.6 s−1, p = 0.23). USPIO uptake in patients was higher in atherosclerotic plaques compared to the patient non-plaque vessel wall (ΔR2* of 24.6 ± 19.8 vs. 7.5 ± 9.3 s−1, p = 0.004). No correlation was found between USPIO uptake and 18F-FDG uptake in atherosclerotic plaques (R2 = 0.03, p = 0.55).ConclusionsFerumoxytol is selectively taken up by atherosclerotic plaques and can thus be used for carotid USPIO-MRI. As USPIO and 18F-FDG uptake in atherosclerotic plaque do not correlate in this cohort, these agents may visualize different pathophysiological aspects of plaque inflammation.
Smits et al. (2017) conducted an observational in Carotid artery stenosis >30% (n=13). Ferumoxytol vs. Non-plaque vessel wall / healthy controls was evaluated on USPIO uptake (ΔR2*) in atherosclerotic plaques vs patient non-plaque vessel wall (p=0.004). Ferumoxytol was selectively taken up by atherosclerotic plaques compared to non-plaque vessel walls (ΔR2* 24.6 vs 7.5 s−1; p=0.004), but did not correlate with 18F-FDG uptake.