Quantitative Potentials of Dynamic Emission Computed Tomography

Budinger, Thomas F.; Derenzo, Stephen E.; Greenberg, William L.; Gullberg, Grant T.; Huesman, R.H.

doi:10.1097/00004728-197902000-00048

Cited by 47 publications

(36 citation statements)

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“…40 A significant response to ACZ was assumed if post-ACZ T c -H M P A O h AU% exceeded the twofold root-mean-square uncertainty ranges of pre-ACZ and post-ACZ uptake measurements. Hemispheric and regional (^3 adjacent sectors) hemodynamic compromise was diagnosed if the respective SAIs after ACZ challenge exceeded the twofold root-meansquare uncertainty ranges of pre-ACZ and post-ACZ indexes.…”

Section: Fjp Jhlmentioning

confidence: 99%

99mTc-HMPAO-SPECT with acetazolamide challenge to detect hemodynamic compromise in occlusive cerebrovascular disease.

Knop

Thie

Fuchs

et al. 1992

Stroke

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Background and Purpose: Insufficiency of collateral supply may lead to low-flow infarcts in severe occlusive cerebrovascular disease. The aim of this study was to evaluate the feasibility of technetium99m-labeled hexamethylpropyleneamine oxime ("Tc-HMPAO) single-photon emission computed tomography (SPECT) to assess hemodynamic compromise in the anterior circulation.Methods: Cerebral blood flow before and after 1 g acetazolamide was analyzed by "Tc-HMPAO-SPECT in 21 symptomatic patients with documented extracranial obstructions. SPECT findings were correlated with the results of angiography, transcranial Doppler sonography, and computed tomographic scan.Results: The acetazolamide-induced increase of cerebral blood flow could be reliably monitored by increase of cerebral "Tc-HMPAO uptake, which varied between 11.4% and 47.6% in the less-affected hemisphere. Increment of hemispheric side-to-side asymmetry of tracer uptake after drug challenge revealed significant restriction of regional vasoreactivity in 11 patients. Agreement in assessing hemodynamic compromise was reached in 81% of patients with ophthalmic artery collaterals on angiography (p<0.001), in 76% with low-flow infarcts on computed tomographic scan (p<0.01), and in 91% with markedly reduced flow velocities on transcranial Doppler (p<0.0001). One patient developed a low-flow infarct in the area predicted by SPECT during follow up.Conclusions: We conclude that Tc-HMPAO-SPECT with acetazolamide challenge is a useful method for assessment of the adequacy of hemispheric collateral pathways in patients with severe occlusive cerebrovascular disease. (Stroke 1992;23:1733-1742

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Section: Fjp Jhlmentioning

confidence: 99%

99mTc-HMPAO-SPECT with acetazolamide challenge to detect hemodynamic compromise in occlusive cerebrovascular disease.

Knop

Thie

Fuchs

et al. 1992

Stroke

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“…24 where PS (ml/min/g) is the product of the capillary permeability and surface area. Therefore, E becomes reduced (E<1) for finite PS.…”

Section: Fitting Proceduresmentioning

confidence: 99%

Measurement of absolute myocardial blood flow with H215O and dynamic positron-emission tomography. Strategy for quantification in relation to the partial-volume effect.

et al. 1988

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An in vivo technique was developed for measuring the absolute myocardial blood flow with H2`50 and dynamic positron-emission tomography. This technique was based on a new model involving the concept of the tissue fraction, which was defined as the fraction of the tissue mass in the volume of the region of interest. The myocardium was imaged dynamically by positron-emission tomography, starting at the time of intravenous bolus injection of 1212O. The arterial input function was measured continuously with a beta-ray detector. A separate image after C`50 inhalation was also obtained for correction of the H2"5O radioactivity in the blood.The absolute myocardial blood flow and the tissue fraction were calculated for 15 subjects with a kinetic technique under region-of-interest analysis. These results seem consistent with their coronary angiographic findings. The mean value of the measured absolute myocardial blood flows in normal subjects was 0.95 0.09 ml/min/g. This technique detected a diffuse decrease of myocardial blood flow in patients with triple-vessel disease. (Circulation 1988;78:104-115) W ith the use of suitable tracers and appropriate mathematical models, positronemission tomography (PET) has the capability ofproviding noninvasive quantitative measurements of physiological functions in organs. However, in the field of cardiac PET, relatively few measurements have been made of the absolute value of the myocardial blood flow (MBF) and metabolism.1,2 The main reason for this concerns the so-called partial volume effect (PVE), 1-6 that is, the spillover effect in radioactivity measurement due to the relatively thin-walled myocardium compared with the spatial resolution of PET,7 and the wall motion of the myocardium. The PVE problem

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“…Other studies [23][24][25][26] are aimed specifically at the reduction of Poisson noise contained in medical (including PET) images, exploiting its statistical properties. It is not clear if this approach is strictly valid in case of PET images [27].…”

Section: Introductionmentioning

confidence: 99%

Properties of Noise in Positron Emission Tomography Images Reconstructed with Filtered-Backprojection and Row-Action Maximum Likelihood Algorithm

et al. 2012

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Noise levels observed in positron emission tomography (PET) images complicate their geometric interpretation. Post-processing techniques aimed at noise reduction may be employed to overcome this problem. The detailed characteristics of the noise affecting PET images are, however, often not well known. Typically, it is assumed that overall the noise may be characterized as Gaussian. Other PET-imaging-related studies have been specifically aimed at the reduction of noise represented by a Poisson or mixed Poisson + Gaussian model. The effectiveness of any approach to noise reduction greatly depends on a proper quantification of the characteristics of the noise present. This work examines the statistical properties of noise in PET images acquired with a GEMINI PET/CT scanner. Noise measurements have been performed with a cylindrical phantom injected with 11 C and well mixed to provide a uniform activity distribution. Images were acquired using standard clinical protocols and reconstructed with filtered-backprojection (FBP) and row-action maximum likelihood algorithm (RAMLA).Statistical properties of the acquired data were evaluated and compared to five noise models (Poisson, normal, negative binomial, log-normal, and gamma). Histograms of the experimental data were used to calculate cumulative distribution functions and produce maximum likelihood estimates for the parameters of the model distributions. Results obtained confirm the poor representation of both RAMLA-and FBP-reconstructed PET data by the Poisson distribution. We demonstrate that the noise in RAMLAreconstructed PET images is very well characterized by gamma distribution followed closely by normal distribution, while FBP produces comparable conformity with both normal and gamma statistics.

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Quantitative Potentials of Dynamic Emission Computed Tomography

Cited by 47 publications

References 0 publications

99mTc-HMPAO-SPECT with acetazolamide challenge to detect hemodynamic compromise in occlusive cerebrovascular disease.

99mTc-HMPAO-SPECT with acetazolamide challenge to detect hemodynamic compromise in occlusive cerebrovascular disease.

Measurement of absolute myocardial blood flow with H215O and dynamic positron-emission tomography. Strategy for quantification in relation to the partial-volume effect.

Properties of Noise in Positron Emission Tomography Images Reconstructed with Filtered-Backprojection and Row-Action Maximum Likelihood Algorithm

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