Background and purpose: Arterial calcification is a process of atherosclerosis, usually taking place within advanced atheromatous plaque. In the coronary arteries, calcification seen on computed tomography (CT) often indicates severe stenosis, and is noted in almost all patients with coronary symptoms. Calcification of the cerebral arteries is also frequently observed on brain CT, but its clinical significance has yet to be clarified. To evaluate the clinical significance of cerebral arterial calcification on brain CT, we investigated the angiographic and transcranial Doppler ultrasonography (TCD) findings of calcified cerebral arteries.
Methods: The subjects were 57 patients with ischemic stroke, all of whom underwent brain CT, digital subtraction cerebral angiography and TCD. Stroke subtypes were defined according to TOAST classification. Two clinicians who were blinded in respect to the patients' clinical history and to each other's interpretation, determined the presence of cerebral arterial calcification and the degree of angiographic stenosis.
Results: Cerebral artery calcification was noted in 23 patients (40%) out of a total of 46 arteries, consisting of 23 internal carotid, 15 vertebral, 5 basilar, 2 middle cerebral and 1 anterior cerebral artery. The patients with calcification were significantly older and more hypertensive than those without calcification. All the patients with calcification showed either large artery atherosclerosis or lacunar stroke. Hemodynamic alterations measured by TCD were rarely observed in calcified arteries. The severity and extent of the atherosclerotic changes were significantly greater in the patients with calcification than those without calcification.
Conclusion: These results suggest that cerebral arterial calcification does not directly indicate hemodynamically significant atherosclerotic stenosis involving calcified segments, but indicates the underlying etiology of either large artery atherosclerosis or lacunar stroke, and raises the possibility of a diffuse atherosclerotic process being present in the cerebral circulation.