scholarly journals Sources of Variability of Resting Cerebral Blood Flow in Healthy Subjects: A Study Using 133Xe SPECT Measurements

2013 ◽  
Vol 33 (5) ◽  
pp. 787-792 ◽  
Author(s):  
Otto M Henriksen ◽  
Christina Kruuse ◽  
Jes Olesen ◽  
Lars T Jensen ◽  
Henrik BW Larsson ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Healthy Subjects ◽  
Single Photon ◽  
Large Fraction ◽  
Photon Emission ◽  
Added Value ◽  
Emission Computed Tomography ◽  
Large Variability ◽  
Subject Variability

Measurements of cerebral blood flow (CBF) show large variability among healthy subjects. The aim of the present study was to investigate the relative effect of established factors influencing CBF on the variability of resting CBF. We retrospectively analyzed spontaneous variability in 430 CBF measurements acquired in 152 healthy, young subjects using 133Xe single-photon emission computed tomography. Cerebral blood flow was correlated positively with both end-tidal expiratory PCO2 (PETCO2) and female gender and inversely with hematocrit (Hct). Between- and within-subject CO2 reactivity was not significantly different. Including PETCO2, Hct and gender in the model reduced between-subject and within-subject variance by 14% and 13.5%, respectively. Withinsubject variability was mainly influenced by PETCO2 and between-subject variability mostly by Hct, whereas gender appeared to be of little added value when Hct was also accounted for. The present study confirms large between-subject variability in CBF measurements and that gender, Hct, and PETCO2 explain only a small part of this variability. This implies that a large fraction of CBF variability may be due to unknown factors such as differences in neuron density or metabolism that could be subject for further studies.

scholarly journals Dipyridamole Dilates Large Cerebral Arteries Concomitant to Headache Induction in Healthy Subjects

2000 ◽  
Vol 20 (9) ◽  
pp. 1372-1379 ◽  
Author(s):  
Christina Kruuse ◽  
Torsten B. Jacobsen ◽  
Lisbeth H. Lassen ◽  
Lars L. Thomsen ◽  
Steen G. Hasselbalch ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Healthy Subjects ◽  
Single Photon ◽  
Photon Emission ◽  
Controlled Study ◽  
Emission Computed Tomography ◽  
Large Artery

Dipyridamole is used for secondary prophylaxis in ischemic stroke and as a vasodilator agent in myocardial scintigraphy. An important side effect to administering dipyridamole is headache. The aim of the current study was to investigate the effects of dipyridamole on cerebral blood flow, large artery diameter, and headache induction. Twelve healthy subjects were included in this single-blind placebo-controlled study in which placebo (0.9% NaCl) and dipyridamole 0.142 mg/kg·min were administered intravenously over 4 minutes 1 hour apart. Blood flow velocity in the middle cerebral artery (Vmca) was recorded by transcranial Doppler and regional cerebral blood flow in the middle cerebral artery (rCBFmca) was measured using single photon emission computed tomography and 133Xenon-inhalation. Blood pressure, heart rate, and pCO2 were measured repeatedly. Headache response was scored every 10 minutes on a verbal scale from 0 to 10 (10 = worst). Dipyridamole caused a decrease in pCO2 ( P < 0.001). pCO2 corrected rCBFmca was 41.7 ± 6.9 mL/100 g ·min after placebo versus 41.2 ± 6.9 after dipyridamole ( P ≥ 0.05). pCO2 corrected Vmca decreased 8.4% ± 11.7 ( P < 0.001) after dipyridamole, indicating a mean 5.6% ± 6.7 ( P = 0.005) relative increase of the arterial diameter. After dipyridamole the median peak headache score was 2 (range 0 to 7) compared with 0 (range 0 to 3) after placebo ( P = 0.02). Dilatation of the middle cerebral artery outlasted the headache response. In conclusion, dipyridamole causes a modest pCO2 independent dilatation of the MCA, which is time-linked to the onset, but not to the cessation, of headache.

scholarly journals Brain Correlates of Memory Processes in Patients with Dementia of Alzheimer's Type: A Spect Activation Study

1998 ◽  
Vol 18 (4) ◽  
pp. 457-462 ◽  
Author(s):  
Dominique Cardebat ◽  
Jean-François Démonet ◽  
Michèle Puel ◽  
Alain Agniel ◽  
Gerard Viallard ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Cerebral Blood Flow ◽  
Single Photon ◽  
Photon Emission ◽  
Memory Task ◽  
Frontal Region ◽  
Emission Computed Tomography ◽  
Regional Cerebral Blood ◽  
Actual Performance

Task-induced changes in regional cerebral blood flow (rCBF) during verbal episodic memory activation were compared in 17 right-handed patients with dementia of the Alzheimer's type (DAT) and 20 healthy volunteers. Regional cerebral blood flow was assessed using single photon emission computed tomography (SPECT) and an injection of 133Xe (xenon, isotope of mass 133) in 21 regions of interest (ROI) during rest, passive listening to 36 words, and memorizing of a 12-word list repeated three times. In healthy subjects, memory—listening comparison showed activation of a distributed system involving several left-sided ROI, especially the posterior inferior frontal region. In patients with DAT, the same pattern of activation was found for listening—rest comparison, and no significant changes were found in memory—listening comparison. During listening compared with rest, significant activation was observed in left-sided hypoperfused regions. A significant correlation between memory performance and rCBF recorded in patients with DAT during the memory task was found only in the right lateral frontal region, a region that was not hypoperfused significantly in patients. The involvement of this region might relate to either retrieval effort or actual performance of patients with DAT on the memory task.

scholarly journals Dose-dependent effects of the selective serotonin reuptake inhibitor citalopram: A combined SPECT and phMRI study

2019 ◽  
Vol 33 (6) ◽  
pp. 660-669 ◽  
Author(s):  
Anouk Schrantee ◽  
Michelle M Solleveld ◽  
Hilde Schwantje ◽  
Willem B Bruin ◽  
Henk-Jan MM Mutsaerts ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Serotonin Transporter ◽  
Single Photon ◽  
Photon Emission ◽  
Occipital Cortex ◽  
Emission Computed Tomography ◽  
Positron Emission ◽  
Pre Treatment ◽  
Dose Dependent

Background: Serotonin transporter blockers, like citalopram, dose-dependently bind to the serotonin transporter. Pharmacological magnetic resonance imaging (phMRI) can be used to non-invasively monitor effects of serotonergic medication. Although previous studies showed that phMRI can measure the effect of a single dose of serotoninergic medication, it is currently unclear whether it can also detect dose-dependent effects. Aims: To investigate the dose-dependent phMRI response to citalopram and compared this with serotonin transporter occupancy, measured with single photon emission computed tomography (SPECT). Methods: Forty-five healthy females were randomized to pre-treatment with placebo, a low (4 mg) or clinically standard (16 mg) oral citalopram dose. Prior to citalopram, and 3 h after, subjects underwent SPECT scanning. Subsequently, a phMRI scan with a citalopram challenge (7.5 mg intravenously) was conducted. Change in cerebral blood flow in response to the citalopram challenge was assessed in the thalamus and occipital cortex (control region). Results: Citalopram dose-dependently affected serotonin transporter occupancy, as measured with SPECT. In addition, citalopram dose-dependently affected the phMRI response to intravenous citalopram in the thalamus (but not occipital cortex), but phMRI was less sensitive in distinguishing between groups than SPECT. Serotonin transporter occupancy showed a trend-significant correlation to thalamic cerebral blood flow change. Conclusion: These results suggest that phMRI likely suffers from higher variation than SPECT, but that these techniques probably also assess different functional aspects of the serotonergic synapse; therefore phMRI could complement positron emission tomography/SPECT for measuring effects of serotonergic medication.

Improvement in Regional Cerebral Blood Flow and Cerebral Vasoreactivity after Extracranial-Intracranial Arterial Bypass

Neurosurgery ◽  
1988 ◽  
Vol 22 (5) ◽  
pp. 913-919 ◽  
Author(s):  
Hunt H. Batjer ◽  
Michael D. Devous ◽  
Phillip D. Purdy ◽  
Bruce Mickey ◽  
Frederick J. Bonte ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Cerebral Blood Flow ◽  
Single Photon ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
Regional Cerebral Blood ◽  
Flow Measurements ◽  
Cerebrovascular Reserve ◽  
Neurological Improvement

Abstract Regional cerebral blood flow was measured with xenon-133 inhalation single photon emission computed tomography in a patient who developed a neurological deficit after carotid ligation. Hemispheric hypoperfusion was noted in resting studies and impaired vasoreactivity was suggested by lack of symmetrical flow augmentation after acetazolamide administration. Because of progressive neurological deterioration, an extracranial-intracranial bypass was performed. After prompt neurological improvement, repeat cerebral blood flow measurements at 1 and 9 weeks postoperatively confirmed improvement in resting flow and vasoreactivity. It is possible that decreased cerebrovascular reserve implied by measurements of vasoreactivity can identify patients who will benefit from surgical revascularization.

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