Is intracranial atherosclerosis an independent risk factor for cerebral atrophy? A retrospective evaluation

Abstract

Background: Our purpose was to study the association between the intracranial atherosclerosis as measured by cavernous carotid artery calcification (ICAC) observed on head CT and atrophic changes of supra-tentorial brain demonstrated by MRI.

Methods: Institutional review board approval was obtained for this retrospective study incorporating 65 consecutive patients presenting acutely who had both head CT and MRI. Arterial calcifications of the intracranial cavernous carotids (ICAC) were assigned a number (1 to 4) in the bone window images from CT scans. These 4 groups were then combined into high (grades 3 and 4) and low calcium (grades 1 and 2) subgroups. Brain MRI was independently evaluated to identify cortical and central atrophy. Demographics and cardiovascular risk factors were evaluated in subjects with high and low ICAC. Relationship between CT demonstrated ICAC and brain atrophy patterns were evaluated both without and with adjustment for cerebral ischemic scores and cardiovascular risk factors.

Results: Forty-six of the 65 (71%) patients had high ICAC on head CT. Subjects with high ICAC were older, and had higher prevalence of hypertension, diabetes, coronary artery disease (CAD), atrial fibrillation and history of previous stroke (CVA) compared to those with low ICAC. Age demonstrated strong correlation with both supratentorial atrophy patterns. There was no correlation between ICAC and cortical atrophy. There was correlation however between central atrophy and ICAC. This persisted even after adjustment for age.

Conclusion: Age is the most important determinant of atrophic cerebral changes. However, high ICAC demonstrated age independent association with central atrophy.

Figure 1

Axial bone window images at the level of the cavernous sinuses for different grades of arterial calcium. LOW CALCIUM SUBGROUP. A: Grade 1: Bilateral grade 1 cavernous carotids. Tangible arterial calcifications. B: Grade 2: Bilateral grade 2 cavernous carotids due to thin scattered calcifications. HIGH CALCIUM SUBGROUP. C: Grade 3: Bilateral grade 3 calcifications. Thick, interrupted on the right and thin confluent on the left. D: Grade 4: Bilateral grade 4 ICAC seen as thick, contiguous calcifications.

Figure 2

Cortical atrophy grades from 1 to 5 on T1-Weighted images (Image based grading spectrum for cortical atrophy has extended between 1 and 10, 10 being the largest degree of sulcal dilatation).

Figure 3

Central atrophy grades from 1 to 5 on T1-Weighted images (Image based grading spectrum for central atrophy has extended between 1 and 10, 10 being the largest degree of ventricular dilatation).