Computed tomography evaluation of intracranial atherosclerosis in Chinese patients with transient ischemic attack or minor ischemic stroke--its distribution and association with vascular risk factors.
OBJECTIVE
Intracranial atherosclerosis has been suggested to be common in Asians. We apply a semi-quantitative CT scoring system to evaluate the degree of intracranial atherosclerotic calcification and determine its distribution, severity, and the associated risk factors. The clinical outcome of these patients after a 3-year follow-up was also evaluated.


METHODS
Sixty consecutive patients diagnosed clinically to have either a transient ischemic attack (TIA) or minor ischemic stroke and underwent early computed tomographic angiography (CTA) were included into the prospective study. Two radiologists evaluated the axial CTA images for any calcification in the precavernous, cavernous and postcavernous segments of intracranial internal carotid artery (ICA), anterior, middle, and posterior cerebral as well as vertebrobasilar arteries, based on a standard CT scoring system for extent (0-4) and thickness (0-4). The composite CT score for extent and thickness of these vascular segments or vessels were recorded for all patients. The worst site (highest composite score) was chosen as the marker of the degree of intracranial atherosclerosis of each patient. The patients were then classified into mild, moderate, and severe groups, according to a composite CT score of 0-2, 3-5, and 6-8, respectively. These findings were gathered with clinical parameters and outcome after a 3-year follow-up period and corresponding statistical analyses were conducted.


RESULTS
The most severely affected vessel was found to be intracranial internal carotid arteries, and severe, moderate, and mild atherosclerosis were present in 16 (26.67%), 30 (50%), and 14 (23.33%) patients, respectively. Using multiple logistic regression analysis, diabetes mellitus (odds ratio = 10.6, P value = .004), and age (odds ratio = 1.07, P value = .02) were found to be significant risk factors for severe intracranial atherosclerosis. Two patients in the severe group, 3 patients in the moderate group, and 1 patient in the mild group were found to have stroke or TIA after a 3-year follow-up, but there was no significant difference among the 3 groups.


CONCLUSIONS
Significant intracranial atherosclerosis as determined by severe CT calcification was common in a cohort of Chinese patients with TIA and minor stroke. Age and diabetes mellitus were independent significant risk factors, and this CT calcification score might serve as an early indicator of intracranial atherosclerotic disease.
Mak
Henry Ka-Fung
HK
Department of Diagnostic Radiology, The University of Hong Kong, Hong Kong. makkf@hkucc.hku.hk
Wong
Chan-Wah
CW
Yau
Kelvin Kai-Wing
KK
Wong
Wai-Ming
WM
Gu
Jing
J
Khong
Pek-Lan
PL
Chan
Bernard Poon-Lap
BP
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D002545:Brain Ischemia / Q000453:epidemiology*; D002114:Calcinosis / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000208:ethnology; D002536:Cerebral Arteries / Q000000981:diagnostic imaging* / Q000473:pathology / Q000503:physiopathology; D018450:Disease Progression; D005260:Female; D006801:Humans; D002537:Intracranial Arteriosclerosis / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000208:ethnology; D002546:Ischemic Attack, Transient / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012307:Risk Factors; D012720:Severity of Illness Index; D020521:Stroke / Q000453:epidemiology*; D014057:Tomography, X-Ray Computed