[Noninvasive measurement of cerebrovascular circulation with the scintillation camera. A neurologic nuclear medicine study].

Repeated CBF-measurements can be performed after inhalation or intravenous injection of 133Xe. After the development of a bicompartmental model by Obrist et al. in 1975 atraumatic CBF-measurements became widely used but there were still some difficulties concerning the sensitivity of different flow-indices towards CBF changes in normals under test conditions or ischemia in stroke patients. Due to the "slippage phenomenon" mostly noncompartmental flow-indices are used for the detection of ischemic brain areas. In this study a scintillation camera, that is usually available in every nuclear medicine department, was used for atraumatic CBF-studies. A collimator consisting of hexagonal lead tubes (septa 0.2 mm thick; FWHM 1.7 cm in 10 cm) was constructed for this purpose. The obtained counting rate varied between 2432 and 9081 cps over the whole hemisphere and 116-1094 cps in regions of approximately 2.5 X 2.5 cm. In 31 patients with CVD CBF was measured with the intracarotid (i.c.) technique and 1 hour later after i.v. 133Xe-injection. Intravenous flow values were comparable to those obtained after i.c. 133Xe injection (fB X MFr = 0.904; p less than 0.001). In 12 of the used 13 regions also significant correlation coefficients were found. In order to estimate the reproducibility of the intravenous injection method CBF-measurements were performed in both hemispheres of 10 patients on two consecutive days. Highly significant correlation coefficients were found for hemispheric blood flow (r = 0.933; p less than 0.001) and temporal, frontotemporal, temporoparietal and praecentral regions, while in the high parietal, frontal and occipital region lower reporducibility was found. Normal CBF-values were obtained from 12 healthy volunteers (MF right hemisphere: 50.7 +/- 4.6 ml/100 g/min; MF left hemisphere: 50.6 +/- 4.6 ml/100 g/min). MF did not show any hyperfrontality, while F1 and the ISI gave highest flow values in frontal regions. The clinical status of 76 patients suffering from cerebral ischemia (68 with flow disturbances in one hemisphere, 8 with vertebrobasilar insufficiency) was estimated by a semiquantitative scorescale at time of admission and after an observation period lasting from 6 to 35 months. In each case CBF was measured twice: once in the subacute stage after onset of symptoms and once after the observation period. The duration of neurologic symptoms (TIA, RIND, CS) was compared to the obtained flow values. A significant relationship was found between the duration of symptoms and impairment of CBF, thus showing the prognostic value of intravenous CBF measurements.(ABSTRACT TRUNCATED AT 400 WORDS)