PET as Part of an Interdisciplinary Approach to Understanding Processes Involved in Reading

1993 ◽  
Vol 4 (5) ◽  
pp. 287-293 ◽  
Author(s):  
Julie A. Fiez ◽  
Steven E. Petersen
Keyword(s):  
Positron Emission Tomography ◽  
Blood Flow ◽  
Information Processing ◽  
Brain Activity ◽  
Interdisciplinary Approach ◽  
Emission Tomography ◽  
Brain Blood Flow ◽  
Positron Emission ◽  
Types Of Information ◽  
Task Conditions

Positron emission tomography (PET) is a recently developed technology that can be used to create images of brain blood flow, which is related to brain activity. By acquiring images of brain blood flow during different task conditions, investigators can isolate activity changes related to specific types of information processing. Several examples demonstrate how regions involved in reading can be identified, and how the results are most interpretable when information from other disciplines is considered.

Brain Blood Flow in the Nitroglycerin (Gtn) Model of Migraine: Measurement Using Positron Emission Tomography and Transcranial Doppler

Cephalalgia ◽  
2002 ◽  
Vol 22 (9) ◽  
pp. 749-757 ◽  
Author(s):  
EM Bednarczyk ◽  
DS Wack ◽  
MY Kassab ◽  
K Burch ◽  
K Trinidad ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Blood Flow ◽  
Transcranial Doppler ◽  
Occipital Cortex ◽  
Anterior Cingulate ◽  
Emission Tomography ◽  
Brain Blood Flow ◽  
Positron Emission ◽  
Subcutaneous Sumatriptan ◽  
History Of

Nitroglycerin has been widely used as a model of experimental migraine. Studies combining measurement of flow velocity using transcranial Doppler (TCD) concurrently with measures of cerebral blood flow (CBF) are uncommon. We report the results of a study combining TCD and positron emission tomography (PET). Healthy volunteers with no personal or family history of migraine underwent measurement of CBF using H215O PET, and velocity using TCD. Measurements were done at baseline, and following i.v. nitroglycerin at 0.125, 0.25 and 0.5 μg/kg per min. Subcutaneous sumatriptan (6 mg) was injected, with CBF and velocity measured 15, 30, and 60 min later. Nitroglycerin was terminated and measurements obtained 30 min later. Six male and six female subjects were studied. Nitroglycerin increased global CBF while flow velocities decreased. Sumatriptan did not have a significant effect on these values. Regions of increased flow included the anterior cingulate, while regions of decreased flow included the occipital cortex. Our data suggest that nitroglycerin induces regional changes in CBF that are similar to changes reported in spontaneous migraine, but produces distinctly different effects on global CBF and velocity.

scholarly journals Reproducibility of Resting Cerebral Blood Flow Measurements with H215O Positron Emission Tomography in Humans

1993 ◽  
Vol 13 (5) ◽  
pp. 748-754 ◽  
Author(s):  
Elizabeth Matthew ◽  
Paul Andreason ◽  
Richard E. Carson ◽  
Peter Herscovitch ◽  
Karen Pettigrew ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regions Of Interest ◽  
Emission Tomography ◽  
Brain Blood Flow ◽  
Flow Measurements ◽  
Positron Emission ◽  
Normal Humans ◽  
Blood Flow Measurements

Two consecutive measurements of resting CBF were carried out in normal volunteers (n = 25) using H215O positron emission tomography. Absolute whole-brain blood flow (WBBF; ml 100 g−1 min−1, mean ± SD) for the first (40.3 ± 6.4) and second (39.3 ± 6.5) measurements was not significantly different (mean % difference 2.3 ± 8.7). Analysis of regions of interest showed no significant differences in absolute regional CBF (rCBF) and normalized (rCBF/WBBF) rCBF. Left-right differences were also not significant. These data demonstrate the reproducibility of resting CBF measurements in normal humans.

scholarly journals Effects of Acetazolamide on Cerebral Blood Flow, Blood Volume, and Oxygen Metabolism: A Positron Emission Tomography Study with Healthy Volunteers

2001 ◽  
Vol 21 (12) ◽  
pp. 1472-1479 ◽  
Author(s):  
Hidehiko Okazawa ◽  
Hiroshi Yamauchi ◽  
Kanji Sugimoto ◽  
Hiroshi Toyoda ◽  
Yoshihiko Kishibe ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Metabolic Rate ◽  
Blood Volume ◽  
Cerebral Blood Volume ◽  
Capillary Blood ◽  
Emission Tomography ◽  
Positron Emission ◽  
Capillary Blood Volume

To evaluate changes in cerebral hemodynamics and metabolism induced by acetazolamide in healthy subjects, positron emission tomography studies for measurement of cerebral perfusion and oxygen consumption were performed. Sixteen healthy volunteers underwent positron emission tomography studies with15O-gas and water before and after intravenous administration of acetazolamide. Dynamic positron emission tomography data were acquired after bolus injection of H215O and bolus inhalation of15O2. Cerebral blood flow, metabolic rate of oxygen, and arterial-to-capillary blood volume images were calculated using the three-weighted integral method. The images of cerebral blood volume were calculated using the bolus inhalation technique of C15O. The scans for cerebral blood flow and volume and metabolic rate of oxygen after acetazolamide challenge were performed at 10, 20, and 30 minutes after drug injection. The parametric images obtained under the two conditions at baseline and after acetazolamide administration were compared. The global and regional values for cerebral blood flow and volume and arterial-to-capillary blood volume increased significantly after acetazolamide administration compared with the baseline condition, whereas no difference in metabolic rate of oxygen was observed. Acetazolamide-induced increases in both blood flow and volume in the normal brain occurred as a vasodilatory reaction of functioning vessels. The increase in arterial-to-capillary blood volume made the major contribution to the cerebral blood volume increase, indicating that the raise in cerebral blood flow during the acetazolamide challenge is closely related to arterial-to-capillary vasomotor responsiveness.

Neural Mechanism of Propofol Anesthesia in Severe Depression

2003 ◽  
Vol 98 (5) ◽  
pp. 1101-1111 ◽  
Author(s):  
Kenichi Ogawa ◽  
Takeshi Uema ◽  
Nobutaka Motohashi ◽  
Masami Nishikawa ◽  
Harumasa Takano ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Statistical Parametric Mapping ◽  
Severe Depression ◽  
Dose Effect ◽  
Emission Tomography ◽  
Association Cortex ◽  
Depressed Patients ◽  
Positron Emission

Background The precise neural mechanisms of propofol anesthesia in humans are still unknown. The authors examined the acute effects of propofol on regional cerebral blood flow (rCBF) using positron emission tomography in patients with severe depression. Methods In six severely depressed patients (mean age, 55.0 yr) scheduled for electroconvulsive therapy, anesthetic levels were monitored by electroencephalography, and rCBF was serially quantified in the awake, sedated, and anesthetized states. The authors used high-resolution positron emission tomography with 15O-labeled water and statistical parametric mapping 99 for imaging and analysis of the data. Results Global cerebral blood flow showed sharp decreases from the awake level during the administration of propofol, decreasing 26.8% in the sedated state and 54.4% in the anesthetized state. Moreover, a dose effect was seen in both parietal cortices and the left lateral prefrontal region with larger regions of relative decrease in rCBF at higher propofol doses. At the higher dose, the values of rCBF in the pulvinar nucleus of the thalamus, the pontine tegmentum, and the cerebellar cortex were also affected. Meanwhile, there were few changes of relative rCBF in the basal frontal lobes during both sedated and anesthetized states. Conclusions As in earlier studies using normal subjects, pronounced suppression in rCBF in the brain stem reticular formation, the thalamus, and the parietal association cortex occurred even in severely depressed patients. However, previously reported decreases in rCBF in the basal frontal lobe were absent in depressed patients.

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