Abstract
Regional cerebral blood flow (rCBF) was measured by 133Xe inhalation technique during acute (Day 1-Day 14), subacute (Day 15-Day 28), and chronic (Day 29-) stage in 68 cases with embolic and 63 cases with thrombotic cerebral artery occlusion. All cases had unilateral supratentorial ischemic events. Diagnostic criteria of embolic and thrombotic cerebral artery occlusion have been reported elsewhere (Jpn Circ J 48 : 50, 1984).
In thrombotic group, mean rCBF of the affected hemisphere was significantly lower than that of the unaffected side, and was fairly constant in all stages (p<0.001). In contrast, mean rCBF of the affected side of embolic cases was significantly lower than that of the unaffected side only in subacute and chronic stages (p<0.02, p<0.001, respectively). Furthermore, mean rCBF of the affected hemisphere in acute stage was significantly higher than that in chronic stage (p<0.02).
When mean rCBF of each case in acute stage was plotted against that in chronic stage, a significant positive correlation was obtained in either hemispheres in both groups. Regression lines of thrombotic cases were approximately equal to the line of Y=X, while mean rCBF of embolic cases in acute stage was higher than that in chronic stage, making regression lines Y=0.47X + 23.1 in the affected hemisphere, and Y=0.74X + 11.0 in the unaffected hemisphere.
Regional CBF of the ischemic hemisphere was expressed as %CBF of corresponding channel in the contralateral hemisphere (relative rCBF). More than 40% of total number of channels showed relative rCBF higher than 100%, and only 21% showed decreased relative rCBF less than 90% in acute stage of embolic group. In chronic stage, these percentage changed to 23% and 50%, respectively. In thrombotic group, 58% of total channels showed the relative rCBF lower than 90% even in acute stage, and regional patterns of CBF showed no significant difference during the course.
High rCBF in acute stage of embolic group was thought to be the reflection of an increase of blood flow after reopening of the previously occluded artery that is frequently observed in embolic cerebral artery occlusion.
From the results of the present study, it is concluded that sequential changes of regional blood flow in cases with embolic cerebral artery occlusion are quite different from those with thrombotic cerebral artery occlusion; i.e., increased rCBF of the affected hemisphere in acute stage of cerebral embolism, and more constant and pronounced decrease of CBF in all stages of cerebral thrombosis.
