Pilot first-in-human CCR2 PET/CT to detect abdominal aortic aneurysm wall instability

Area of Science:

• Cardiovascular Imaging
• Molecular Imaging
• Vascular Biology

Background:

• Abdominal aortic aneurysm (AAA) rupture is a life-threatening event, and current risk stratification methods are insufficient.
• Existing imaging focuses on size and growth, overlooking critical cellular and molecular indicators of instability.
• There is a significant unmet need for advanced imaging techniques to assess AAA instability.

Purpose of the Study:

• To evaluate the feasibility of C-C chemokine receptor type 2 (CCR2) Positron Emission Tomography/Computed Tomography (PET/CT) imaging in assessing abdominal aortic aneurysm (AAA) instability.
• To determine if CCR2 PET/CT signals correlate with AAA wall characteristics and rupture potential.
• To explore CCR2 expression in AAA tissue and its relationship with inflammatory markers.

Main Methods:

• A pilot, prospective, case-control study involving patients with and without AAAs.
• Intravenous administration of a CCR2-specific radiotracer followed by PET/CT scans.
• Analysis of PET/CT signals in AAA walls, correlated with patient data, anatomical segmentation, and rupture potential index (RPI).
• Histomorphic analysis of surgical AAA specimens for CCR2 content, macrophage infiltration, and matrix integrity.

Main Results:

• AAA patients showed higher CCR2 radiotracer signals in aortic tissue compared to controls.
• No correlation was found between CCR2 signal intensity and AAA diameter.
• Higher CCR2 signals, particularly in the posterior wall, correlated significantly with RPI (P=0.03).
• Histomorphology revealed elevated CCR2, increased macrophages, matrix metalloproteinase activity, and elastin degradation in AAAs.

Conclusions:

• First-in-human study demonstrating the feasibility of CCR2 PET/CT molecular imaging for AAA.
• CCR2 PET/CT can identify increased abdominal aortic aneurysm wall instability.
• This imaging approach shows potential for identifying AAAs at higher risk of progression and rupture.