Imaging the Human Brain with Functional CT Imaging

2011 ◽  
pp. 314-323
Author(s):  
Sotirios Bisdas ◽  
Tong San Koh
Keyword(s):  
Cerebral Perfusion ◽  
Tumor Imaging ◽  
Low Cost ◽  
Distributed Parameter ◽  
Cerebrovascular Reserve ◽  
Brain Death Diagnosis ◽  
Tracer Kinetic ◽  
Processing Software ◽  
Functional Ct ◽  
Multi Detector Computed Tomography

Recent advances in multi-detector computed tomography (CT) have revitalized its role in the clinical routine. In the field of cerebral perfusion, CT provides a rapid, low-cost functional imaging, which by the utilization of a suitable tracer kinetic analysis can provide valuable information in many clinical applications, like acute stroke, cerebrovascular reserve capacity, vasospasm after subarachnoidal hemorrhage, cerebral trauma, tumor imaging, and brain death diagnosis. The limitations of the existing commercially available post processing software are discussed and a new distributed-parameter tracer kinetic model for generating more accurate perfusion parametric maps is introduced.

scholarly journals Tracer-Kinetic Models for Measuring Cerebral Blood Flow Using Externally Detected Radiotracers

1987 ◽  
Vol 7 (4) ◽  
pp. 443-463 ◽  
Author(s):  
Kenneth B. Larson ◽  
Joanne Markham ◽  
Marcus E. Raichle
Keyword(s):  
Kinetic Models ◽  
Counting Rate ◽  
Compartment Model ◽  
Distributed Parameter ◽  
High Temporal Resolution ◽  
Yield Model ◽  
Residue Detection ◽  
Positron Emission ◽  
Tracer Kinetic ◽  
Tissue Systems

All tracer-kinetic models currently employed with positron-emission tomography (PET) are based on compartmental assumptions. Our first indication that a compartmental model might suffer from severe limitations in certain circumstances when used with PET occurred when we implemented the Kety tissue-autoradiography technique for measuring CBF and observed that the resulting CBF estimates, rather than remaining constant (to within predictable statistical uncertainty) as expected, fell with increasing scan duration T when T > 1 min. After ruling out other explanations, we concluded that a one-compartment model does not possess sufficient realism for adequately describing the movement of labeled water in brain. This article recounts our search for more realistic substitute models. We give our derivations and results for the residue-detection impulse responses for unit capillary-tissue systems of our two candidate distributed-parameter models. In a sequence of trials beginning with the simplest, we tested four progressively more detailed candidate models against data from appropriate residue-detection experiments. In these, we generated high-temporal-resolution counting-rate data reflecting the history of radiolabeled-water uptake and washout in the brains of rhesus monkeys. We describe our treatment of the data to yield model-independent empirical values of CBF and of other parameters. By substituting these into our trial-model functions, we were able to make direct comparisons of the model predictions with the experimental dynamic counting-rate histories, confirming that our reservations concerning the one-compartment model were well founded and obliging us to reject two others. We conclude that a two-barrier distributed-parameter has the potential of serving as a substitute for the Kety model in PET measurements of CBF in patients, especially when scan durations for T > 1 min are desired.

Design of a Multichannel High Precision Instrument in Portable Data Acquisition

2014 ◽  
Vol 644-650 ◽  
pp. 3718-3721
Author(s):  
Ai Hua Dong ◽  
Xiao Yan Kang ◽  
Yun Yi Wang
Keyword(s):  
Data Processing ◽  
Data Acquisition ◽  
Data Storage ◽  
Low Cost ◽  
Main Function ◽  
Synchronous Sampling ◽  
Sample Data ◽  
Visual Basic6.0 ◽  
Processing Software ◽  
Data Acquisition Unit

For the need of multi-channel simultaneous sampling in the modeling and identification of power system, a portable data acquisition system is introduced. It can sample multi-channel data simultaneously, and also have a mass data storage. The system is composed of data acquisition card and PC processing software. The C8051F410 MCU is the core of the data acquisition unit card. It not only provides multi-channel synchronous sampling, large storage capacity, easy to carry and low cost, but also can run offline, and bidirectional interaction with PC software. The data processing software is programmed by Visual Basic6.0. Its main function is sending sample orders and the sample data processing. It can store and process the sample data, also it can set the sampling parameters of the card. Through actual verification, the system is easy to use and meets the precision of requirement.

scholarly journals The Effect of Acetazolamide on Regional Cerebral Blood Oxygenation at Rest and under Stimulation as Assessed by MRI

1994 ◽  
Vol 14 (5) ◽  
pp. 742-748 ◽  
Author(s):  
Harald Bruhn ◽  
Andreas Kleinschmidt ◽  
Henning Boecker ◽  
Klaus-Dietmar Merboldt ◽  
Wolfgang Hänicke ◽  
...  
Keyword(s):  
Cerebral Perfusion ◽  
Blood Oxygenation ◽  
Reserve Capacity ◽  
Resonance Imaging ◽  
Gradient Echo ◽  
Vasomotor Tone ◽  
Regional Cerebral Blood ◽  
Cerebrovascular Reserve ◽  
Magnetic Resonance Imaging Mri ◽  
Cerebral Blood Oxygenation

The sensitivity of gradient echo magnetic resonance imaging (MRI) to changes in cerebral blood oxygenation (CBO) has been introduced for mapping functional brain activation. Here, we report that this approach allows monitoring autoregulation in the human brain under vasodilatory stress. Following the administration of acetazolamide, signal intensities of deoxyhemoglobin-sensitive images increased in cortical and subcortical gray matter and to a lesser extent in white matter. This result reflects a venous hyperoxygenation stemming from an increase in cerebral perfusion with oxygen consumption remaining constant. In addition, pharmacologic induction of vasodilation attenuated activity-related MRI signal changes in the visual cortex under photic stimulation. Although intersubject variability was high, this finding indicates individually persisting autoregulatory responsiveness to functional challenge despite an “exhausted” reserve capacity. It is suggested that recording CBO by MRI will foster our understanding of modulation of vasomotor tone and cerebral perfusion. Furthermore, this technique may prove valuable for assessing the cerebrovascular reserve capacity in patients with carotid artery occlusive disease.

Improvement in cognitive function and cerebral perfusion after bur hole surgery in an adult with moyamoya disease

2011 ◽  
Vol 115 (2) ◽  
pp. 347-349 ◽  
Author(s):  
Lionel Calviere ◽  
Isabelle Catalaa ◽  
Fabienne Marlats ◽  
Anne-Christine Januel ◽  
Jacques Lagarrigue ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Cognitive Function ◽  
Mr Imaging ◽  
Cognitive Dysfunction ◽  
Moyamoya Disease ◽  
Cerebral Perfusion ◽  
Cerebral Hypoperfusion ◽  
Complete Regression ◽  
Cerebrovascular Reserve ◽  
Old West

Recent studies have suggested that cognitive impairment may be a common complication in adults with moyamoya disease (MMD). However, the mechanisms of cognitive dysfunction have not been clarified. Whether cognitive impairment may occur as a consequence of cerebral hypoperfusion and may improve after revascularization surgery has not been determined. A 39-year-old West Indian woman with subacute dysexecutive cognitive syndrome and no history of stroke was diagnosed with MMD. Magnetic resonance imaging showed an old, small cerebral infarction in the left frontal white matter and no evidence of recent cerebral ischemia. Perfusion MR imaging with acetazolamide challenge demonstrated a reduced cerebrovascular reserve in both frontal lobes. Revascularization with bur hole surgery was performed, which resulted in complete regression of initial cognitive impairment. Improvement in cognitive function correlated with the development of transdural collaterals on angiography and improvement in cerebral perfusion on MR imaging. This case suggests a relationship between cognitive dysfunction and cerebral hypoperfusion in MMD. Cognitive impairment may be potentially reversible after bur hole surgery and cerebral perfusion improvement.

scholarly journals Evaluation of Cerebrovascular Reserve Capacity in Symptomatic and Asymptomatic Internal Carotid Stenosis With Transcranial Doppler

2016 ◽  
pp. 917-925 ◽  
Author(s):  
I. DOUVAS ◽  
D. MORIS ◽  
G. KARAOLANIS ◽  
C. BAKOYIANNIS ◽  
S. GEORGOPOULOS
Keyword(s):  
Carotid Artery ◽  
Carotid Stenosis ◽  
Transcranial Doppler ◽  
Internal Carotid ◽  
Low Cost ◽  
Reserve Capacity ◽  
Control Group ◽  
Cerebrovascular Reserve ◽  
Cerebrovascular Reserve Capacity ◽  
Asymptomatic Patients

Cerebrovascular reserve capacity (CVRC) is a hemodynamic parameter indicating the brain’s capacity to overcome ischemia. Transcranial Doppler (TCD) is a useful device to measure CVRC, with high availability and low cost. The aim of the study is to investigate asymptomatic patients with affected CVRC, who could benefit from CEA. One hundred and forty five consecutive patients (60 symptomatic and 65 asymptomatic), with internal carotid artery (ICA) stenosis >70 % and 20 healthy individuals without internal carotid stenosis underwent TCD-inhalation CO2 tests in order to measure the CVRC in both hemispheres of each patient. CVRC between asymptomatic and symptomatic patients were significantly different in the 95 % confidence interval (CI) as well as the mean CVRC value in contralateral carotid artery. The correlation between CVRC in the carotid artery with stenosis and the existence of symptoms is significant at the 0.01 level. Additionally, symptoms and CVRC of the contralateral carotid artery are also significant at the 0.05 level and CVRC values in asymptomatic patients and the control group at the 0.01 level. None of the covariant factors, except the age, are significantly correlated with CRVC. CVRC could be an early mark-index to evaluate the risk of stroke in this group of patients and to design their therapeutic approach.

scholarly journals Quantification of cerebral perfusion and cerebrovascular reserve using Turbo‐QUASAR arterial spin labeling MRI

2019 ◽  
Vol 83 (2) ◽  
pp. 731-748 ◽  
Author(s):  
Moss Y. Zhao ◽  
Lena Václavů ◽  
Esben T. Petersen ◽  
Bart J. Biemond ◽  
Magdalena J. Sokolska ◽  
...  
Keyword(s):  
Arterial Spin Labeling ◽  
Cerebral Perfusion ◽  
Spin Labeling ◽  
Cerebrovascular Reserve
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