A1 Refereed original research article in a scientific journal
RAPID CALCULATION OF REGIONAL CEREBRAL BLOOD-FLOW AND DISTRIBUTION VOLUME USING IODINE-123-IODOAMPHETAMINE AND DYNAMIC SPECT
Authors: ITO H, IIDA H, BLOOMFIELD PM, MURAKAMI M, INUGAMI A, KANNO I, FUKUDA H, UEMURA K
Publisher: SOC NUCLEAR MEDICINE INC
Publication year: 1995
Journal: Journal of Nuclear Medicine
Journal name in source: JOURNAL OF NUCLEAR MEDICINE
Journal acronym: J NUCL MED
Volume: 36
Issue: 4
First page : 531
Last page: 536
Number of pages: 6
ISSN: 0161-5505
Abstract
Iodine-123-iodoamphetamine (IMP) is commonly used as a flow tracer for SPECT due to its large first-pass extraction fraction. Significant clearance from the brain, however, causes changes in distribution and underestimation of CBF values when a conventional microsphere model is applied to prolonged data acquisition. We have developed a rapid method to calculate CBF images in which clearance effects are taken into account. Methods: A dynamic SPECT scan was obtained from five subjects (four patients with cerebral infarctions and one healthy volunteer) following intravenous injection of IMP lasting 1 min. The arterial input function was obtained by frequent blood sampling and measurement of the octanol extraction ratio. The dynamic images were weighted and integrated so that the look-up table procedures yielded values of CBF and distribution volume (V-d) simultaneously. Results: Calculated Values for CBF and V-d were consistent with those determined by nonlinear least squares fitting [CBF: Y = 1.03X - 0.30 (ml/100 ml/min), r = 0.998, p < 0.001; V-d: Y = 0.99X - 0.11 (ml/ml), r = 0.99, p < 0.001] and calculated CBF correlated significantly with CBF measured by PET [Y = 0.85X - 0.15 (ml/100 ml/min), r = 0.92, p < 0.001]. Conclusion: This technique is valid for estimating CBF.
Iodine-123-iodoamphetamine (IMP) is commonly used as a flow tracer for SPECT due to its large first-pass extraction fraction. Significant clearance from the brain, however, causes changes in distribution and underestimation of CBF values when a conventional microsphere model is applied to prolonged data acquisition. We have developed a rapid method to calculate CBF images in which clearance effects are taken into account. Methods: A dynamic SPECT scan was obtained from five subjects (four patients with cerebral infarctions and one healthy volunteer) following intravenous injection of IMP lasting 1 min. The arterial input function was obtained by frequent blood sampling and measurement of the octanol extraction ratio. The dynamic images were weighted and integrated so that the look-up table procedures yielded values of CBF and distribution volume (V-d) simultaneously. Results: Calculated Values for CBF and V-d were consistent with those determined by nonlinear least squares fitting [CBF: Y = 1.03X - 0.30 (ml/100 ml/min), r = 0.998, p < 0.001; V-d: Y = 0.99X - 0.11 (ml/ml), r = 0.99, p < 0.001] and calculated CBF correlated significantly with CBF measured by PET [Y = 0.85X - 0.15 (ml/100 ml/min), r = 0.92, p < 0.001]. Conclusion: This technique is valid for estimating CBF.
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