Objective: For diagnosing patients with ischemic cerebrovascular disease, non-invasive count-based method with (15)O(2) and H (2) (15) O positron-emission tomography (PET) data is widely used to measure asymmetric increases in oxygen extraction fraction (OEF). For shortening study time, we have proposed dual-tracer autoradiographic (DARG) protocol in which (15)O(2) gas and C(15)O(2) gas are sequentially administrated within short period. In this paper, we evaluated feasibility of the non-invasive count-based method with the DARG protocol.
Methods: Twenty-three patients [67.8 +/- 9.9 (mean +/- SD) years] with chronic unilateral brain infarction were examined by the use of measurements of asymmetric OEF elevation. As DARG protocol, (15)O(2) and C(15)O(2) gases were inhaled with 5-min interval and dynamic PET data were acquired for 8 min. Quantitative OEF (qOEF) image was computed with PET data and arterial input function. Ratio image of (15)O(2) and C(15)O(2) phases of PET data was computed as count-based OEF (cbOEF) image. The asymmetric indices (AI) of qOEF (qOEF-AI) and cbOEF (cbOEF-AI) were obtained from regions of interest symmetric placed on left and right sides of cerebral hemisphere. To optimize the summation time of PET data for the cbOEF image, qOEF and cbOEF images with various summation times were compared.
Results: Image quality of cbOEF image was better than that of qOEF image. The best correlation coefficient of 0.94 was obtained when the cbOEF image was calculated from 0 to 180 s of (15)O(2) summed image and 340 to 440 s of C(15)O(2) summed image.
Conclusion: Using the appropriate summation time, we obtained the cbOEF image with good correlation with qOEF image, which suggests non-invasive cbOEF image can be used for evaluating the degree of misery perfusion in patients with chronic unilateral brain infarction. The count-based method with DARG protocol has a potential to dramatically reduce the examination time of (15)O PET study.
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Evaluation of utility of asymmetric index for count-based oxygen extraction fraction on dual-tracer autoradiographic method for chronic unilateral brain infarction.
Ann Nucl Med
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Department of Investigative Radiology, National Cardiovascular Center Research Institute, 5-7-1 Fujishirodai, Suita, Osaka 565-8565, Japan.
Objective: For diagnosing patients with ischemic cerebrovascular disease, non-invasive count-based method with (15)O(2) and H (2) (15) O positron-emission tomography (PET) data is widely used to measure asymmetric increases in oxygen extraction fraction (OEF). For shortening study time, we have proposed dual-tracer autoradiographic (DARG) protocol in which (15)O(2) gas and C(15)O(2) gas are sequentially administrated within short period. In this paper, we evaluated feasibility of the non-invasive count-based method with the DARG protocol.
View Article and Find Full Text PDFShorter examination method for the diagnosis of misery perfusion with count-based oxygen extraction fraction elevation in 15O-Gas PET.
J Nucl Med
February 2008
Biomedical Imaging Research Center, University of Fukui, Fukui, Japan.
Unlabelled: (15)O-Gas PET is useful for evaluating hemodynamic status in patients with ischemic cerebrovascular disease. To reduce examination time and exposure to radioactive gas, we assessed a count-based method with shorter continuous (15)O(2) gas inhalation.
Methods: Twenty-five patients (66 +/- 13 [mean +/- SD] y old) with unilateral cerebrovascular stenoocclusive disease were examined by use of measurements of asymmetric oxygen extraction fraction (OEF) elevation.
Diagnosis of misery perfusion using noninvasive 15O-gas PET.
J Nucl Med
October 2006
Biomedical Imaging Research Center, University of Fukui, Fukui, Japan.
Unlabelled: To avoid arterial blood sampling and complicated analyses in 15O-gas PET studies, we evaluated a noninvasive technique using the count-based method for measuring asymmetric increases in oxygen extraction fraction (OEF) in cerebrovascular disease.
Methods: Eighteen patients (mean age +/- SD, 61 +/- 16 y) with atherothrombotic large-cerebral-artery disease were studied for the measurement of hemodynamic parameters using the 15O-gas steady-state method with inhalation of 15O2, C15O2, and C15O. All patients also underwent H2(15)O PET with the bolus injection method.
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