Chronic middle cerebral artery occlusion: a hemodynamic and metabolic study with positron-emission tomography.
OBJECTIVE
Chronic middle cerebral artery (MCA) occlusion is more common than generally thought. It is important to assess the cerebral hemodynamic status in patients with this chronic condition. We investigated the cerebral hemodynamic and metabolic disturbances in these patients in relation to the development of the collateral vasculature.


METHODS
We studied 13 patients with chronic unilateral MCA occlusion who had a minor or no stroke by using positron-emission tomography (PET). PET was performed by the oxygen 15 ((15)O) gas steady-state inhalation method. The intracranial arteries were evaluated by digital subtraction angiography. We divided the patients into 2 subgroups according to whether they had a normal or increased oxygen extraction fraction (OEF) in the occluded MCA territory and compared the 2 groups.


RESULTS
Of the 13 patients, 9 were classified into the normal OEF and 4 were classified into the increased OEF group. In the increased OEF group, the mean OEF values were also increased in the territories of the ipsilateral anterior cerebral artery, ipsilateral posterior cerebral artery, and contralateral MCA. The patients in the increased OEF group had more than 1 steno-occlusive lesion in the major intracranial arteries (P = .008). Three of the 4 patients in the increased OEF group also had vascular lesions in the collateral pathways to the MCA territory.


CONCLUSIONS
Most patients with chronic MCA occlusion did not show severe hemodynamic impairment. Those with increased OEF tended to have other areas of severe hemodynamic impairment and other vascular lesions, especially in the collateral pathways.
Tanaka
M
M
Departments of Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Osaka, Japan.
Shimosegawa
E
E
Kajimoto
K
K
Kimura
Y
Y
Kato
H
H
Oku
N
N
Hori
M
M
Kitagawa
K
K
Hatazawa
J
J
D000328:Adult; D000368:Aged; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000209:etiology / Q000378:metabolism*; D002908:Chronic Disease; D005260:Female; D006439:Hemodynamics; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000150:complications / Q000000981:diagnostic imaging* / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010104:Oxygen Radioisotopes / Q000493:pharmacokinetics*; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics
D010104:Oxygen Radioisotopes; D019275:Radiopharmaceuticals