Concurrent Molecular Magnetic Resonance Imaging of Inflammatory Activity and Extracellular Matrix Degradation for the Prediction of Aneurysm Rupture

Background: Molecular magnetic resonance imaging is a promising modality for the characterization of abdominal aortic aneurysms(AAAs). The combination of different molecular imagingbiomarkers may improve the assessment of the risk of rupture. This study investigates the feasibility of imaging inflammatory activity and extracellular matrixdegradation by concurrent dual-probe molecular magnetic resonance imaging in an AAA mouse model. Methods: Osmotic minipumps with a continuous infusion of Ang II (angiotensin II; 1000 ng/[kg·min]) to induce AAAs were implanted in apolipoprotein-deficient mice (N=58). Animals were assigned to 2 groups. In group 1 (longitudinal group, n=13), imaging was performed once after 1 week with a clinical dose of a macrophage-specific iron oxide–based probe ( ferumoxytol, 4 mgFe/kg, surrogate marker for inflammatory activity) and an elastin-specific gadolinium-based probe (0.2 mmol/kg, surrogate marker for extracellular matrixdegradation). Animals were then monitored with death as...