PET Measurement of rCBF in the presence of a neurochemical tracer

Converse, Alexander K.; Barnhart, Todd E.; Dabbs, Kevin; DeJesus, Onofre T.; Larson, Julie A.; Nickles, Robert J.; Schneider, Mary L.; Roberts, Andrew

doi:10.1016/j.jneumeth.2003.09.006

Cited by 15 publications

(12 citation statements)

References 20 publications

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“…16,17 Simultaneous measurements of blood flow and receptor binding would be able to experimentally measure the effects of blood flow on radiotracer binding. By repeatedly injecting a short-lived blood flow tracer in the presence of a long-lived neuroreceptor ligand, measurements of both CBF and receptor occupancy are possible using PET alone, 18 but such experiments are highly technically demanding and have not been performed to our knowledge. With the availability of combined PET/MRI scanners, however, it is now possible to continuously monitor CBF using arterial spin labeling techniques 19,20 during a neuroreceptor PET imaging experiment.…”

Section: Introductionmentioning

confidence: 99%

Effects of flow changes on radiotracer binding: Simultaneous measurement of neuroreceptor binding and cerebral blood flow modulation

Sander

Mandeville

Wey

et al. 2017

J Cereb Blood Flow Metab

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The potential effects of changes in blood flow on the delivery and washout of radiotracers has been an ongoing question in PET bolus injection studies. This study provides practical insight into this topic by experimentally measuring cerebral blood flow (CBF) and neuroreceptor binding using simultaneous PET/MRI. Hypercapnic challenges (7% CO) were administered to non-human primates in order to induce controlled increases in CBF, measured with pseudo-continuous arterial spin labeling. Simultaneously, dopamine D/D receptor binding of [C]raclopride or [F]fallypride was monitored with dynamic PET. Experiments showed that neither time activity curves nor quantification of binding through binding potentials ( BP) were measurably affected by CBF increases, which were larger than two-fold. Simulations of experimental procedures showed that even large changes in CBF should have little effect on the time activity curves of radiotracers, given a set of realistic assumptions. The proposed method can be applied to experimentally assess the flow sensitivity of other radiotracers. Results demonstrate that CBF changes, which often occur due to behavioral tasks or pharmacological challenges, do not affect PET [C]raclopride or [F]fallypride binding studies and their quantification. The results from this study suggest flow effects may have limited impact on many PET neuroreceptor tracers with similar properties.

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Section: Introductionmentioning

confidence: 99%

Effects of flow changes on radiotracer binding: Simultaneous measurement of neuroreceptor binding and cerebral blood flow modulation

Sander

Mandeville

Wey

et al. 2017

J Cereb Blood Flow Metab

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“…The modulated injection method of Converse et al . [3] is well suited to a factor analysis approach. They used a region of interest and allowed the fallypride to reach a point where it had little time variability before injection of fluoromethane.…”

Section: Discussionmentioning

confidence: 99%

Dual-Tracer PET Using Generalized Factor Analysis of Dynamic Sequences

et al. 2013

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Purpose With single-photon emission computed tomography, simultaneous imaging of two physiological processes relies on discrimination of the energy of the emitted gamma rays, whereas the application of dual-tracer imaging to positron emission tomography (PET) imaging has been limited by the characteristic 511-keV emissions. Procedures To address this limitation, we developed a novel approach based on generalized factor analysis of dynamic sequences (GFADS) that exploits spatio-temporal differences between radiotracers and applied it to near-simultaneous imaging of 2-deoxy-2-[18F]fluoro-D-glucose (FDG) (brain metabolism) and 11C-raclopride (D2) with simulated human data and experimental rhesus monkey data. We show theoretically and verify by simulation and measurement that GFADS can separate FDG and raclopride measurements that are made nearly simultaneously. Results The theoretical development shows that GFADS can decompose the studies at several levels: (1) It decomposes the FDG and raclopride study so that they can be analyzed as though they were obtained separately. (2) If additional physiologic/anatomic constraints can be imposed, further decomposition is possible. (3) For the example of raclopride, specific and nonspecific binding can be determined on a pixel-by-pixel basis. We found good agreement between the estimated GFADS factors and the simulated ground truth time activity curves (TACs), and between the GFADS factor images and the corresponding ground truth activity distributions with errors less than 7.3±1.3 %. Biases in estimation of specific D2 binding and relative metabolism activity were within 5.9±3.6 % compared to the ground truth values. We also evaluated our approach in simultaneous dual-isotope brain PET studies in a rhesus monkey and obtained accuracy of better than 6 % in a mid-striatal volume, for striatal activity estimation. Conclusions Dynamic image sequences acquired following near-simultaneous injection of two PET radiopharmaceuticals can be separated into components based on the differences in the kinetics, provided their kinetic behaviors are distinct.

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“…Ikoma et al 79 then presented work which paralleled Koeppe's work using 18 F-FDG and 11 C-flumazenil, and their results were consistent with those of Koeppe. Converse et al 80, 81 adapted the technique to PET measurement of regional cerebral blood flow using 17 F-fluoromethane (inhaled, T 1/2 = 64.5 sec) in the presence of a neurochemical tracer, 18 F-fallypride. The objective of this work was to demonstrate proof-of-principle for measuring rapidly changing blood flow patterns while also measuring the neuroreceptor status over a longer timescale.…”

Section: Techniques For Rapid Multi-tracer Pet Tumor Imagingmentioning

confidence: 99%

Methodology for Quantitative Rapid Multi-Tracer PET Tumor Characterizations

Kadrmas¹,

Hoffman²

2013

Theranostics

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Positron emission tomography (PET) can image a wide variety of functional and physiological parameters in vivo using different radiotracers. As more is learned about the molecular basis for disease and treatment, the potential value of molecular imaging for characterizing and monitoring disease status has increased. Characterizing multiple aspects of tumor physiology by imaging multiple PET tracers in a single patient provides additional complementary information, and there is a significant body of literature supporting the potential value of multi-tracer PET imaging in oncology. However, imaging multiple PET tracers in a single patient presents a number of challenges. A number of techniques are under development for rapidly imaging multiple PET tracers in a single scan, where signal-recovery processing algorithms are employed to recover various imaging endpoints for each tracer. Dynamic imaging is generally used with tracer injections staggered in time, and kinetic constraints are utilized to estimate each tracers' contribution to the multi-tracer imaging signal. This article summarizes past and ongoing work in multi-tracer PET tumor imaging, and then organizes and describes the main algorithmic approaches for achieving multi-tracer PET signal-recovery. While significant advances have been made, the complexity of the approach necessitates protocol design, optimization, and testing for each particular tracer combination and application. Rapid multi-tracer PET techniques have great potential for both research and clinical cancer imaging applications, and continued research in this area is warranted.

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PET Measurement of rCBF in the presence of a neurochemical tracer

Cited by 15 publications

References 20 publications

Effects of flow changes on radiotracer binding: Simultaneous measurement of neuroreceptor binding and cerebral blood flow modulation

Effects of flow changes on radiotracer binding: Simultaneous measurement of neuroreceptor binding and cerebral blood flow modulation

Dual-Tracer PET Using Generalized Factor Analysis of Dynamic Sequences

Methodology for Quantitative Rapid Multi-Tracer PET Tumor Characterizations

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