Extent of intra-arterial calcification on head CT is predictive of the degree of intracranial atherosclerosis on digital subtraction angiography.

BACKGROUND

Intracranial intra-arterial calcifications (ICAC) are a common finding on head CT examinations, but their significance is not known. The aim of this study is to determine if a relationship exists between ICAC on head CT and the presence of a high-grade atherosclerotic stenosis on cerebral angiography.

METHODS

This was a retrospective study of 108 consecutive patients admitted to the stroke service at Parkland Hospital in Dallas, Tex., USA. Each patient had undergone a head CT and catheter-based angiographic study to meet the inclusion criteria. Demographic information was recorded along with CT imaging data in regards to the amount of calcification. Angiographic images were reviewed independently, and a comparison was made to determine if calcification was predictive of finding a high-grade stenosis on angiography.

RESULTS

A total of 108 consecutive patients with a mean age of 56 +/- 12 years were studied. Of the 540 vessels studied, 65 (12%) were found to have a stenosis of >or=50% on angiography, and 71 (13.1%) were found to have a calcium grade of 3 or 4 on head CT. ICAC appeared to be more common in the anterior circulation compared to the posterior circulation. Patients with grade 3 or 4 calcification of an intracranial vessel on head CT were more likely to have a stenosis of >or=50% on cerebral angiography.

CONCLUSIONS

The presence of ICAC on head CT appears to correlate with the presence of an underlying intracranial stenosis on angiography. Further study is required to validate these preliminary findings.