DOTATATE PETMRI AAA Study

Summary

Participation Requirements

Description

The prevalence of abdominal aortic aneurysm (AAA) in those over 65 years is 4-8% and rising. Currently, AAA size is the only metric to determine risk of growth/rupture; we are unable to image the underlying disease process. Using size alone is problematic. For small AAAs there is no consensus betwee...

The prevalence of abdominal aortic aneurysm (AAA) in those over 65 years is 4-8% and rising. Currently, AAA size is the only metric to determine risk of growth/rupture; we are unable to image the underlying disease process. Using size alone is problematic. For small AAAs there is no consensus between surgical societies on appropriate surveillance intervals. AAA growth is non-linear and thus some small AAAs may rupture between screening intervals. Macrophage mediated inflammation leads to weakening of the aortic wall. Our own laboratory work indicates macrophages correlate with AAA severity in mice. In humans, activated macrophages express SomatoSTatin Receptor 2 (SSTR2). For the first time ever, using a radiotracer probe specific for SSTR 2 (gallium-dotatate), we will detect activated macrophages in AAAs using Positron Emission Tomography- Magnetic Resonance Imaging (PET-MRI). Patients attending the University Health Network (UHN) Vascular clinic undergoing ultrasound surveillance of small AAAs of differing sizes will be imaged with Ga-Dotatate PET-MRI. We will correlate aneurysm size and anatomical information with in-vivo imaging of aortic macrophages detected with Ga-Dotatate, to determine the risk of aneurysm growth.

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