Rationale: Amyloid beta (Ab) is mainly known for its role in Alzheimer's disease (AD)
pathology. However, Ab seems not only to be involved in AD pathology, but also in
atherosclerosis, which might explain the remarkable similarities in risk factors between
these two pathologies. In vitro studies suggest that a major part of this association is
based on the ability of amyloid to lead to macrophage activation and thus inflammation. These
data lead to the hypothesis that Ab is associated with plaque vulnerability.
18F-Flutemetamol is a PET tracer with high affinity for Ab. This has been extensively studied
in AD patients.
Objective: To validate 18F-Flutemetamol PET in the evaluation of plaque vulnerability.
Study design: A cross-sectional validation study. Study population: 25 adults, who have
recently (<14days) experienced a transient ischemic attack (TIA) or stroke with a carotid
artery plaque of ≥30% and without evidence of another etiology than carotid atherosclerosis
(i.e. cardiac or small vessel).
Of these 25 patients, 10 patients will be included who have been scheduled for carotid
endarterectomy (CEA). The other 15 will be selected of patients who are not scheduled to
undergo CEA.
Intervention: All patients will undergo a PET/MRI scan with 18F-Flutemetamol, either before
the scheduled CEA or within the first 30 days following the cerebrovascular event. Imaging
will include the carotid and coronary arteries as well as the brain.
Main study parameters/endpoints: Tracer uptake in the carotid artery will be correlated to
vulnerable plaque characteristics as assessed by MRI. In the 10 CEA patients, tracer uptake
and MR imaging of different plaque characteristics will be validated with plaque histology of
the surgically removed specimen.
Nature and extent of the burden and risks associated with participation, benefit and group
relatedness: There is no additional benefit for study subjects. Study subjects will receive
the same treatment as non-participating patients. Patients will be screened for in- and
exclusion criteria to minimize risks.
For optimal MR imaging patients will be injected with a Gadolinium based contrast agent,
which is a common procedure and associated with very low risk of complications. The PET
tracer 18F-flutemetamol has been studied extensively and is currently used in patients with
AD. Adverse events were not frequent and mainly mild. The radioactivity dose will be around
6.8 mSv.