Intracranial Vessel Wall Lesions on 7T MRI (Magnetic Resonance Imaging)

Abstract

Background and Purpose— Intracranial vessel wall lesions are a novel imaging marker of intracranial atherosclerosis (ICAS), but data on their occurrence and risk factors are lacking. Our aim was to study the frequency, distribution, and risk factors of intracranial vessel wall lesions on 7T magnetic resonance imaging in patients with a history of vascular disease. Methods— Within the SMART-MR study (Second Manifestations of Arterial Disease-Magnetic Resonance), cross-sectional analyses were performed in 130 patients (68±9 years) with assessable 7T intracranial vessel wall–magnetic resonance imaging data. Associations between vascular risk factors and ICAS burden, defined as the total number of vessel wall lesions, were estimated using linear regression analyses with ICAS burden as the dependent variable, adjusted for age and sex. Results— Ninety-six percent of patients had ≥1 vessel wall lesion. The mean±SD (range) ICAS burden was 8.5±5.7 (0–32) lesions. Significant associations were found between ICAS burden and age ( b =2.0 per +10 years; 95% CI, 0.81– 3.10), systolic blood pressure ( b =0.9 per +10 mm Hg; 95% CI, 0.27–1.42), diabetes mellitus ( b =3.2 for presence of diabetes mellitus; 95% CI, 0.79–5.72), hemoglobin A1c level ( b =1.2 per +1%; 95% CI, 0.19–2.26), apoB (apolipoprotein-B) ( b =4.7 per +1 g/L; 95% CI, 0.07–9.35), and hs-CRP (high-sensitivity C-reactive protein) level ( b =2.7 for hs-CRP >3 mg/L; 95% CI, 0.22–5.11). No significant associations were found with sex, smoking, and other lipid-factors. Conclusions— Vessel wall lesions are a novel and direct magnetic resonance imaging marker of ICAS. In this cohort, 96% of patients had at least 1 lesion on 7T vessel wall–magnetic resonance imaging. More lesions were found with older age, higher systolic blood pressure, diabetes mellitus, and higher levels of hemoglobin A1c, apoB, and hs-CRP.

Intracranial Atherosclerotic Burden on 7T MRI Is Associated with Markers of Extracranial Atherosclerosis: The SMART-MR Study

“…This is in line with early postmortem studies that reported frequencies approaching 100% in older age. 27,28 Furthermore, the distribution of vessel wall lesions, which we recently reported, 12 was also in line with the distribution of plaques in those postmortem studies, particularly the increased involvement of the larger cerebral arteries compared with the smaller ones. These findings suggest that vessel wall MR imaging at 7T allows a more accurate approximation of the ICAS burden, compared with other neuroimaging methods.…”

“…Vessel wall MR imaging directly visualizes the pathologic vessel wall, enabling more accurate measurement of the ICAS burden. 11,12,26 A very high frequency of ICAS was found in the current population, 12 especially compared with other neuroimaging studies. This is in line with early postmortem studies that reported frequencies approaching 100% in older age.…”

“…More details regarding arterial or segmental distribution can be found in our prior publication. 12 Examples of vessel wall lesions in a 76-year-old male patient are shown in the Figure. Age-and sex-adjusted linear regression analyses showed that cIMT was significantly associated with a higher ICAS burden (b 4 0.53 lesions per þ0.1 mm; 95% CI, 0.06-0.98 lesions).…”

“…From June 2016 to October 2017, we included 147 patients participating in the second follow-up examination of the SMART-MR study who had intracranial vessel wall MR imaging performed as part of a 7T MR imaging of the brain. 12 A flowchart of the study sample is provided in the On-line Figure. Seventeen patients were excluded from the current study because of artifacts hampering vessel wall MR imaging assessment of $1 major segment of the circle of Willis (major segments included the distal internal carotid artery and primary branches [M1, A1, P1] of the anterior, middle, and posterior cerebral arteries), leaving 130 patients for the final analysis. For the current study, measurements of extracranial atherosclerosis and risk factor assessment, including questionnaire data and blood and urine sampling, were obtained (median, 2.3 years; range, 0.6-8.6 years) before the 7T MR imaging.…”

“…11 Vessel wall lesions are a novel neuroimaging marker of ICAS, which can be assessed using intracranial vessel wall MR imaging. 12 Vessel wall MR imaging enables visualization of the intracranial arterial walls, allowing a more direct evaluation of ICAS. 13 Currently, 7T is the highest field strength at which vessel wall MR imaging has been performed in humans in vivo and has been shown to be superior to lower field strengths in the detection of vessel wall anomalies.…”