scholarly journals Maximizing Precision in Quantitative Autoradiographic Determination of Tissue Tracer Concentration Using Exposure Optimization

1986 ◽  
Vol 6 (4) ◽  
pp. 499-504 ◽  
Author(s):  
James L. Lear
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Optical Density ◽  
Digital Image ◽  
Precise Determination ◽  
Tracer Concentration ◽  
Image Analyzers

The relationships between tissue tracer concentrations, length of time of tissue contact with film, and the darkness of resulting autoradiographic images were explored. Operational equations were then developed relating ranges of film darkening to the ranges of tracer concentration contained within the sections. These equations were solved and used to define ranges of optical density that are optimal for precise determination of tracer concentration using digital image analyzers. The solutions indicated that optimal optical densities are a function of the range of tracer concentrations in the sections. For autoradiograms of typical cerebral blood flow and metabolism tracers, exposure should be controlled to produce images that are significantly less dark than what is generally considered pleasing to the eye.

Tc-99m HMPAO/SPECT Determination of Regional Cerebral Blood Flow Changes in Schizophrenics

1990 ◽  
Vol 15 (12) ◽  
pp. 904-907 ◽  
Author(s):  
BELKIS ERBAS ◽  
HAKAN KUMBASAR ◽  
G??NAYDIN ERBENGI ◽  
COSKUN BEKDIK
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Cerebral Blood Flow ◽  
Regional Cerebral Blood ◽  
Hmpao Spect ◽  
Flow Changes

Brain Death in the Newborn

PEDIATRICS ◽  
1989 ◽  
Vol 84 (3) ◽  
pp. 429-437
Author(s):  
Stephen Ashwal ◽  
Sanford Schneider
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Death ◽  
Clinical Findings ◽  
Term Infants ◽  
Clinical Criteria ◽  
Brain Dead ◽  
Electroencephalographic Activity ◽  
Radionuclide Uptake

The clinical courses of 18 preterm and term infants less than 1 month of age in whom brain death was diagnosed were retrospectively reviewed. Clinical diagnosis was determined neurologically and included (1) coma, (2) apnea, manifested by inability to sustain respiration, and (3) absent brainstem reflexes. Electroencephalograms were performed in all patients; 17 patients had adequate cerebral blood flow as estimated by radionuclide imaging. The results indicate that (1) neurodiagnostic tests such as electroencephalograms and radionuclide scanning reconfirmed clinically determined brain death in only one half to two thirds of patients; (2) electrocerebral silence in the absence of barbiturates, hypothermia, or cerebral malformations during 24 hours was confirmatory of brain death if the clinical findings remained unchanged; (3) absence of radionuclide uptake associated with initial electrocerebral silence was associated with brain death; (4) term infants clinically brain dead for 2 days and preterm infants brain dead for 3 days did not survive despite electroencephalogram or cerebral blood flow status; and (5) phenobarbital levels > 25 µg/ mL may suppress electroencephalographic activity in this age group. The findings suggest that determination of brain death in the newborn can be made solely by using clinical criteria. Confirmatory neurodiagnostic studies are of value because they can potentially shorten the period of observation.

Longitudinal Determination of Cerebral Blood Flow Velocity in Neonates with the Doppler Technique

1987 ◽  
Vol 18 (04) ◽  
pp. 218-221 ◽  
Author(s):  
H. Shuto ◽  
A. Yasuhara ◽  
T. Sugimoto ◽  
S. Iwase ◽  
Y. Kobayashi ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Flow Velocity ◽  
Blood Flow Velocity ◽  
Cerebral Blood Flow Velocity ◽  
Doppler Technique

RADIONUCLIDE CEREBRAL BLOOD FLOW IMAGING AS AN ADJUNCT IN THE DETERMINATION OF BRAIN DEATH IN CHILDREN

1982 ◽  
Vol 10 (3) ◽  
pp. 215
Author(s):  
Bernard H. Holzman ◽  
Richard G. Curless ◽  
George N. Sfakianakis ◽  
Cosimo Ajmone-Marsan ◽  
Jorge E. Montes
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Death ◽  
Flow Imaging ◽  
Blood Flow Imaging

scholarly journals Evaluation of [123I]Isopropyliodoamphetamine as a Tracer for Local Cerebral Blood Flow Using Direct Autoradiographic Comparison

1982 ◽  
Vol 2 (2) ◽  
pp. 179-185 ◽  
Author(s):  
James L. Lear ◽  
Robert F. Ackermann ◽  
Motonobu Kameyama ◽  
David E. Kuhl
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Partition Coefficient ◽  
Brain Uptake ◽  
Local Cerebral Blood Flow ◽  
Mean Values ◽  
Brain Uptake Index ◽  
First Pass ◽  
Potential Use

We investigated [123I]isopropyliodoamphetamine (IMP) for potential use in the autoradiographic determination of local cerebral blood flow (LCBF) in animals. The technique of direct autoradiographic comparison, derived from double radionuclide autoradiography, was used to compare the simultaneous uptakes of IMP and [14C]iodoantipyrine (IAP), a reference tracer, in awake and anesthetized rats. This new technique offers several advantages over the previously developed methods of comparing tracers, brain uptake index and first pass extraction ratio. These include the avoidance of disrupting normal cerebral blood–brain tracer exchange and the ability to compare uptakes at substructural levels, whereas the other methods are limited to larger areas. Mean values of LCBF obtained with IMP agreed closely with those using IAP, from 20 to 300 ml/100 g/min. Because IMP was found to have an extremely high effective brain:blood partition coefficient, approximately 25:1, a linear uptake tracer model could be used for IMP yielding more precise values than could IAP for LCBF values above 150. IMP was found to measure choroid plexus flows much more accurately than IAP, values being greater than 500 for IMP compared to approximately 200 for IAP. Because the mechanism of the extremely high partition coefficient of IMP is not yet defined, however, care must be used in measuring LCBF with IMP where the trapping mechanisms of normal vessels may be disrupted.

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