Tadashi Kanda

Regional Cerebral Blood Volume and Hematocrit Measured in Normal Human Volunteers by Single-Photon Emission Computed Tomography

Single-photon emission computed tomography (SPECT) was used for the measurement of regional cerebral blood volume (CBV) and hematocrit (Hct) in normal healthy human volunteers (mean age 30 ± 8 years). Regional cerebral red blood cell (RBC) volume and plasma volume were determined separately and their responses to carbon dioxide were investigated. Ten right-handed healthy volunteers were the subjects studied. SPECT scans were performed following intravenous injection of the RBC tracer (99mTc-labeled RBC) and plasma tracer (99mTc-labeled human serum albumin) with an interval of 48 h. Regional cerebral Hct was calculated as the regional ratio between RBC and plasma volumes and then was used for calculating CBV. Mean regional CBV in the resting state was 4.81 ± 0.37 ml/100 g brain, significantly greater in the left hemisphere compared with the right by 3.8% (p < 0.01). Mean regional RBC volumes (1.50 ± 0.09 ml/100 g brain) were less than mean regional plasma volumes (3.34 ± 0.28 ml/100 g brain), and mean regional cerebral Hcts were 31.3 ± 1.8%, which was 75.9 ± 2.1% of the large-vessel Hct. During 5% CO2 inhalation, increases in plasma volume (2.48 ± 0.82%/mmHg Paco2) were significantly greater than for RBC volume (1.46 ± 0.48%/mmHg Paco2). Consequently, the cerebral-to-large-vessel Hct ratio was reduced to 72.4 ± 2.2%. Results emphasize the importance of cerebral Hct for the measurement of CBV and indicate that regional cerebral Hcts are not constant when shifted from one physiological state to another.

Regional cerebral blood flow during an attack of vertebrobasilar insufficiency.

Using technetium-99m-labeled hexamethylpropyleneamineoxime [( 99mTc]HM-PAO) and single-photon emission computed tomography, we measured changes in regional cerebral blood flow in a 58-year-old man during an attack of vertebrobasilar insufficiency. Angiography demonstrated compression of the left vertebral artery by the osteophytes of cervical spondylosis when the patient turned his head to the left. Measured in the orthostatic position while turning his head to the left during a typical attack of vertebrobasilar insufficiency, regional cerebral blood flow was significantly reduced in the left cerebellum and the right occipital region. Our study illustrates the capability of [99mTc]HM-PAO single-photon emission computed tomography to measure transient reductions in regional cerebral blood flow and to relate these changes to the pathophysiology of vertebrobasilar insufficiency.

Ataxic hemiparesis with reductions of ipsilateral cerebellar blood flow.

Regional cerebellar blood flow was measured in a patient with left-sided ataxic hemiparesis, using single-photon emission computed tomography and N-isopropyl-p-[123I]Iodoamphetamine. X-ray computed tomography revealed a small infarct in the paramedian portion of the right upper basis pontis. Blood flow was markedly reduced in the contralateral cerebellar hemisphere corresponding to the side of ataxia. The present study emphasizes the value of the three-dimensional functional imaging of the cerebellum to investigate the responsible lesion for ataxia and to study function of the cerebro-cerebellar circuits.

Gender differences in health‐related quality of life among stroke patients

Background:u2003 To determine whether differences in health‐related quality of life (HRQOL) exist between male and female stroke patients and, if present, to identify factors influencing these differences.

Increase in cerebrospinal fluid and plasma levels of 3-methoxy-4-hydroxyphenylglycol in acute stroke.

BACKGROUND AND PURPOSEn3-Methoxy-4-hydroxyphenylglycol is known to be a principal metabolite of brain norepinephrine and to be released into the blood and cerebrospinal fluid in association with activation of the central noradrenergic system. We examined changes in plasma and cerebrospinal fluid levels of 3-methoxy-4-hydroxyphenylglycol during acute stroke to see if there might be a correlation between these and the patients clinical state.nnnMETHODSnWe measured plasma levels of 3-methoxy-4-hydroxyphenylglycol in 32 control subjects and in 50 patients with brain hemorrhage and 57 patients with brain infarction who were admitted to the hospital within 72 hours after onset. In addition, we estimated 3-methoxy-4-hydroxyphenylglycol concentrations in the cerebrospinal fluid of 37 patients with brain infarction and eight control patients.nnnRESULTSnMean +/- SEM values for plasma 3-methoxy-4-hydroxyphenylglycol in the patients with brain hemorrhage and those with brain infarction were 7.3 +/- 0.5 and 6.6 +/- 0.5 ng/ml, respectively. Both values were significantly higher than that obtained in the 32 control subjects (4.6 +/- 0.3 ng/ml, p less than 0.01). Plasma levels of 3-methoxy-4-hydroxyphenylglycol correlated well with state of consciousness and prognosis. The mean +/- SEM level of 3-methoxy-4-hydroxyphenylglycol in the cerebrospinal fluid of the 37 patients with brain infarction (10.9 +/- 0.6 ng/ml) was also significantly higher than that in the eight control patients (7.9 +/- 0.6 ng/ml, p less than 0.01).nnnCONCLUSIONSnThe observed increase in plasma and cerebrospinal fluid levels of 3-methoxy-4-hydroxyphenylglycol implies that the activity of the central noradrenergic neurons may be enhanced at the onset of stroke, and these levels may be related to some extent to the clinical state and prognosis of stroke patients.