Atherosclerotic Carotid Plaque components correlated with Cerebral Damage at 7T

Embolisms, caused by (a) (ruptured) atherosclerotic plaque(s) in the carotid
artery, can cause a TIA (Transient Ischemic Attack) or an ischemic stroke.
Patients undergo a carotid endarterectomy for removal of these atherosclerotic
lesions. The relation between the composition of the atherosclerotic plaque and
1) pre- and postoperative embolisms and 2) (recurrent) infarcts after surgery,
were investigated in the Athero-Express study1. We found that patients with a
fibrotic plaque had a lower risk for recurrent TIA or stroke than patient
groups with a more lipid-rich plaque. Patients with a more inflamed plaque
showed more embolisations (measured with Trans Cranial Doppler (TCD)). In
addition, a high ration of neovasculature with intra plaque bleeding was a
strong predictor for cardiovascular events throughout the whole body. Thus, the
classically defined measures for plaque vulnerability (plaque bleeding, large
lipid lakes and local inflammation) were all related with adverse outcomes
peri-operatively as well as during follow up.

Recently, a 7 Tesla human MRI (Magnetic Resonance Imaging) scanner became
available in the University Medical Center Utrecht (UMCU). This new technique
creates the possibility to visualize carotid artery plaques using high
resolution in vivo MRI and to correlate specific plaque components with
cerebral damage in humans.

Correlate plaque characteristics, determined on high resolution 7 Tesla MRI,
with cerebral damage ((clinically silent) cerebral (micro) infarcts or bleeds),
also seen on 7 Tesla MRI. As gold standard histology of the plaques will be
obtained

Patients scheduled for an endarterectomy of (one of) the carotid arteries are
included via the vascular surgeon. These patients
have had a TIA or stroke, or are asymptomatic with a partially occluded carotid
artery.(>70% stenosis)
About one day before surgery the patients are scheduled for an MRI scan of the
head/neck area in the 7 Tesla MRI scanner. During this MRI scan the brain will
be evaluated for micro infarct/bleeding damage. In the neck area, several MR
images with several weightings will be aqcuired for plaque visualization and
characterization. This will take approximately 75 minutes (including
preparation of the patient). The biggest area of the plaque (culprit lesion)
will be located at a certain distance from the carotid bifurcation. During the
operation the plaque is excised and immediately processed. The segment with the
biggest plaque (culprit lesion) is located and fixated in formalin for
histological analysis. This segment is cut and stained for presence of:
collagen, macrophages, smooth muscle cells, lipids, thrombus and endothelium
(microvessels(neovasculature)). (Athero-Express studie) Additionally, several
other segments will be fixated in formalin and subsequently stained.
(approximately 50% of the plaque will be available for histology)

Nearly negligible risks, only the gadolinium injection could lead to rare
side-effects, but by following the exclusion criteria very strictly
this will be minimized.