Association between Carotid Plaque Characteristics and Cerebral White Matter Lesions: One-Year Follow-Up Study by MRI

Objective: To prospectively assess the relation between carotid plaque characteristics and the development of new cerebral white matter lesions (WMLs) at MRI. Methods: Fifty TIA/stroke patients with ipsilateral 30-69% carotid stenosis underwent MRI of the plaque at baseline. Total plaque volume and markers of vulnerability to thromboembolism (lipid-rich necrotic core [LRNC] volume, fibrous cap [FC] status, and presence of intraplaque hemorrhage [IPH]) were assessed. All patients also underwent brain MRI at baseline and after one year. Ipsilateral cerebral WMLs were quantified with a semiautomatic method. Results: Mean WML volume significantly increased over a one-year period (6.52 vs. 6.97 mm3, P = 0.005). WML volume at baseline and WML progression did not significantly differ (P>0.05) between patients with 30-49% and patients with 50-69% stenosis. There was a significant correlation between total plaque volume and baseline ipsilateral WML volume (Spearman ¿ = 0.393, P = 0.005). There was no significant correlation between total plaque volume and ipsilateral WML progression. There were no significant associations between LRNC volume and WML volume at baseline and WML progression. WML volume at baseline and WML progression did not significantly differ between patients with a thick and intact FC and patients with a thin and/or ruptured FC. WML volume at baseline and WML progression also did not significantly differ between patients with and without IPH. Conclusion: The results of this study indicate that carotid plaque burden is significantly associated with WML severity, but that there is no causal relationship between carotid plaque vulnerability and the occurrence of WMLs. © 2011 Kwee et al

Volumetric measurements (mm³) at baseline and after one year.

<p>Volumetric measurements (mm³) at baseline and after one year.</p

Multisequence MR images of a plaque in the internal carotid artery obtained at baseline (upper row) and after one year (bottom row).

<p>The TOF and T2w TSE images at baseline are slightly blurred due to patient motion. There is no obvious change of plaque morphology. There is a plaque with a LRNC and IPH (asterisks) at baseline and at 1-year follow-up. There is a disruption of the FC at both time points (arrows).</p

Results of Spearman rank correlation analyses for associations between clinical parameters, ipsilateral WML volume at baseline and ipsilateral WML volume progression after one year. Significant results are displayed in bold.

a<p>Hypertension was defined as a systolic blood pressure ≥140 mm Hg and/or a diastolic blood pressure ≥90 mm Hg, or treatment with antihypertensive medication.</p>b<p>Diabetes mellitus was defined as reported use of medication for diabetes mellitus or fasting plasma glucose level ≥126 mg/dl.</p>c<p>Patients were categorized into current, former and never smokers.</p><p>NA: not applicable</p

Patient characteristics (n = 50).

<p>Patient characteristics (n = 50).</p

Scatter plots showing the relation between total plaque volume and ipsilateral WML volume at baseline (A) and ipsilateral WML volume difference after one year (B); and between LRNC volume and ipsilateral WML volume at baseline (C) and ipsilateral WML volume difference after one year (D).

<p>Box-and-Whisker plots showing the relation between fibrous cap status and WML volume at baseline (E) and WML volume difference after one year (F). Box-and-Whisker plots showing the relation between intraplaque hemorrhage and WML volume at baseline (G) and WML volume difference after one year (H).</p

Transverse T2-weighted TSE and fluid-attenuated inversion recovery images showing WMLs, mainly located adjacent to the ventricles (arrows).

<p>Transverse T2-weighted TSE and fluid-attenuated inversion recovery images showing WMLs, mainly located adjacent to the ventricles (arrows).</p

Co-registered T1-weighted TFE, TOF, T2-weighted TSE, pre- and post-contrast T1-weighted TSE images of a transverse section of a plaque in the internal carotid artery.

<p>The right bottom panel displays the plaque components: red = lumen; green = outer vessel wall; yellow = LRNC; orange = calcifications; remaining vessel wall area = fibrous tissue. IPH was scored as being present (asterisk in T1-weighted TFE and TOF images) and the FC was designated as thin and/or ruptured (arrow in post-contrast T1-weighted TSE image).</p