Imaging of Aneurysm Wall Inflammation Using Positron Emission Tomography.

Rationale: Aneurysm development, progression and rupture are characterised by extensive inflammation, dominated by the infiltration of T-cells, B-cells and macrophages. Recent studies into the pathophysiology of aneurysm wall degradation suggest a close relation between increased mechanical stress and the local activation of infiltrated lymphocytes and macrophages. The non-invasive detection of aneurysm wall inflammation, using 18-fluorodeoxyglucose positron emission tomography (FDG-PET) might therefore provide valuable information on the extend of the disease and could clarify the role of mechanical stress on the propagation of aneurysm wall inflammation.

Objective: Correlation of FDG uptake and in vitro aneurysm wall tensile strength. (primary objective). The effect of aneurysm sac depressurisation, after endovascular aneurysm repair, on aneurysm wall inflammation (secondary objective).

Study design: Observational case series (pilot). Study population: Patients scheduled for conventional (open) and endovascular aneurysm repair.

Main study parameters: Standard uptake value (SUV) measurements to asses FDG uptake in the aneurysm wall and in vitro aneurysm wall strength (N/mm).

Nature and extent of the burden and risks associated with participation,

benefit and group relatedness: Patients scheduled for conventional (open) or endovascular aneurysm repair are admitted to the hospital the day before surgery. At that point all patients will be evaluated using FDG-PET. Although intake of sugar-free liquids is permitted, glucose intake is restricted 6 hours prior to FDG-PET imaging. One hour after intravenous injection of 200-220 MBq FDG, whole body emission and transmission images will be acquired. To determine inflammation markers ( e.g. CRP), blood and urine samples will be collected prior to the operation and again 6 weeks after surgery. For in vitro aneurysm wall tensile strength testing wall specimens will be harvested during conventional aneurysm repair.