Determination of regional cerebral blood flow in patients with cerebral infarction. Use of fluoromethane labeled with fluorine 18 and positron emission tomography
G. G. Celesia, R. E. Polcyn, J. E. Holden, R. J. Nickles, R. A. Koeppe and S. J. Gatley
Regional cerebral blood flow (rCBF) was determined using the tissue kinetic
of fluoromethane labeled with fluorine 18 and positron emission tomography
(PET) in 13 normal subjects and 21 patients with cerebrovascular diseases.
The mean brain rCBF was 42.9 +/- 4.3 mL/100 g/min during the resting state.
The highest rCBF (60 +/- 8 mL/100 g/min) was noted in the mesial occipital
region corresponding to cortical area 17. All 17 cases of cerebral ischemic
infarcts had depressed rCBF in the hemisphere ipsilateral to the infarct.
Every area of decreased density shown in the conventional computed
tomograms (CT) was detected on the PET as an area of decreased rCBF (mean
rCBF of infarcted area, 14.3 +/- 6 mL/100 g/min). The PET images showed a
wider area of depressed rCBF than the region of the anatomic infarct. Five
types of remote effects were noted in areas without structural damage: (1)
decreased flow in the thalamus and caudate ipsilateral to the infarct; (2)
decreased flow in the hemisphere contralateral to the cerebral infarct; (3)
decreased flow in the cerebellar hemisphere contralateral to the cerebral
infarct; (4) decreased flow in the visual cortex distal to the optic
radiation lesion; and (5) decreased flow in the frontal cortex ipsilateral
to the infarct. The effects in the contralateral hemisphere and the
cerebellum were present only in the acute postictal phase. In four cases of
transient ischemic attacks, rCBF was normal. It is concluded that this
technique of measuring rCBF is a reliable method of identifying cerebral
ischemia and that the determination of the extent of impaired rCBF provides
a more accurate assessment of the region of brain dysfunction than CTs.
