Abstract
BackgroundWe quantified myocardial blood flow with 82Rb PET using parameters of the generalized Renkin-Crone model estimated from 82Rb and 15O-water images reconstructed with time-of-flight and point spread function modeling. Previous estimates of rubidium extraction have used older-generation scanners without time-of-flight or point spread function modeling. We validated image-derived input functions with continuously collected arterial samples.MethodsNine healthy subjects were scanned at rest and under pharmacological stress on the Siemens Biograph mCT with 82Rb and 15O-water PET, undergoing arterial blood sampling with each scan. Image-derived input functions were estimated from the left ventricle cavity and corrected with tracer-specific population-based scale factors determined from arterial data. Kinetic parametric images were generated from the dynamic PET images by fitting the one-tissue compartment model to each voxel’s time activity curve. Mean myocardial blood flow was determined from each subject’s 15O-water k2 images. The parameters of the generalized Renkin-Crone model were estimated from these water-based flows and mean myocardial 82Rb K1 estimates.ResultsImage-derived input functions showed improved agreement with arterial measurements after a scale correction. The Renkin-Crone model fit (a = 0.77, b = 0.39) was similar to those previously published, though b was lower.ConclusionsWe have presented parameter estimates for the generalized Renkin-Crone model of extraction for 82Rb PET using human 82Rb and 15O-water PET from high-resolution images using a state-of-the-art time-of-flight-capable scanner. These results provide a state-of-the-art methodology for myocardial blood flow measurement with 82Rb PET.Electronic supplementary materialThe online version of this article (doi:10.1186/s13550-016-0215-6) contains supplementary material, which is available to authorized users.
Highlights
We quantified myocardial blood flow with 82Rb PET using parameters of the generalized Renkin-Crone model estimated from 82Rb and 15O-water images reconstructed with time-of-flight and point spread function modeling
An ideal image-derived input function (IDIF) might be expected to have a higher peak value, since no correction for internal-body dispersion was applied to the arterial input function (AIF)
These results suggest that IDIF correction could be beneficial for 82Rb kinetic modeling, due to poorer resolution from larger positron range and higher myocardium-to-blood-pool contrast
Summary
We quantified myocardial blood flow with 82Rb PET using parameters of the generalized Renkin-Crone model estimated from 82Rb and 15O-water images reconstructed with time-of-flight and point spread function modeling. Previous estimates of rubidium extraction have used older-generation scanners without time-of-flight or point spread function modeling. Crone model parameters for rubidium using canine or human MBF data from microspheres [10], 13N-ammonia [5, 11], and 15O-water [12, 13] Most of these studies used older-generation PET systems with 2D or reduceddose 3D acquisitions. When point spread function (PSF) modeling is included in reconstruction, MBF estimates from 82Rb PET may be higher [16]; such calculations were performed using an extraction model [11] derived from non-TOF, non-PSF images. Presotto et al [17] demonstrated the quantitative superiority of PSF + TOF for dynamic cardiac reconstructions using a thorax/heart phantom filled with either 18F alone or 18F and 13N (to simulate dynamically varying contrast), in both static and moving configurations
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