TEMPORAL PATTERN OF BLOOD-VOLUME CHANGE IN CEREBRAL INFARCTION - EVALUATION WITH DYNAMIC CONTRAST-ENHANCED T2-ASTERISK-WEIGHTED MR-IMAGING

OBJECTIVE. The purposes of this study were to evaluate the temporal pa ttern of blood volume change in cerebral infarction and to provide a g uideline in the interpretation of blood volume data, which are known t o vary according to the stage of infarction. SUBJECTS AND METHODS. Thi rty-three patients with large middle cerebral infarctions were examine d one to three times (one time in 20 patients, mio times in eight pati ents, and three times in five patients) after the onset of stroke by d ynamic contrast-enhanced T2-weighted MR imaging and MR angiography. A total of 54 infarctions (29 in an acute stage [up to 7 days], 15 in a subacute stage [8-21 days], and 10 in a chronic stage [22-35 days]) w ere included. After blood volume maps were created, blood volume ratio s (blood volume of the infarcted region divided by blood volume of cor responding contralateral region) were compared at different stages. Li kewise, findings on MR angiography were compared at different stages. RESULTS. Mean blood volume ratios in each stage of infarction were 0.4 6 in the acute stage, 1.48 in the subacute stage, and 0.73 in the chro nic stage (p <.001). Recanalization of occluded arteries occurred in 2 1% of infarctions in the acute stage and 80% in the subacute stage. In farctions with recanalization had higher blood volume ratios than did those without recanalization (p <.001). A biphasic pattern of blood vo lume ratios was found in 13 patients who underwent at least two MR exa minations: increased blood volume in the subacute stage and decreased blood volume in the chronic stage, regardless of recanalization (p <.0 1). CONCLUSION. Blood volume that initially decreases in cerebral infa rction increases in the subacute stage, reflecting reperfusion hyperem ia. Blood volume decreases again in the chronic stage. The time interv al between onset of stroke and MR examination must be considered for c orrect interpretation of blood volume data in cerebral infarction at v arious stages.