Arterial Input Function Derived from Pairwise Correlations Between PET-image Voxels

Abstract

A metabolite corrected arterial input function is a prerequisite for quantification of positron emission tomography (PET) data by compartmental analysis. This quantitative approach is also necessary for radioligands without suitable reference regions in brain. The measurement is laborious and requires cannulation of a peripheral artery, a procedure that can be associated with patient discomfort and potential adverse events. A non invasive procedure for obtaining the arterial input function is thus preferable. In this study, we present a novel method to obtain image-derived input functions (IDIFs). The method is based on calculation of the Pearson correlation coefficient between the time-activity curves of voxel pairs in the PET image to localize voxels displaying blood-like behavior. The method was evaluated using data obtained in human studies with the radioligands [ 11 C]flumazenil and [ 11 C]AZ10419369, and its performance was compared with three previously published methods. The distribution volumes (V T ) obtained using IDIFs were compared with those obtained using traditional arterial measurements. Overall, the agreement in V T was good (B3% difference) for input functions obtained using the pairwise correlation approach. This approach performed similarly or even better than the other methods, and could be considered in applied clinical studies. Applications to other radioligands are needed for further verification.

Test–retest reproducibility of [11C]PBR28 binding to TSPO in healthy control subjects

“…Assuming that part of this variation is methodologically determined, this suggests that reproducibility could be further improved if this component of the analysis is removed. An important aim for future research will therefore be to investigate methods for [ 11 C]PBR28 quantification without the need of arterial blood sampling, such as the use of an image-derived input function [34] in relation to test-retest reproducibility.…”

In vivo imaging of synaptic loss in Alzheimer’s disease with [18F]UCB-H positron emission tomography

“…So, the input function was derived from dynamic PET images [19]. Briefly, the method extracts time series of radiotracer activity in the carotid arteries [33]. The identification of voxels belonging to the carotids is based on the computation of the Pearson product-9 moment correlation coefficient between a "seeding region" and voxels in a mask containing the carotid.…”

“…The identification of voxels belonging to the carotids is based on the computation of the Pearson product-9 moment correlation coefficient between a "seeding region" and voxels in a mask containing the carotid. As, during the first 2 minutes, radioactivity is mainly localized in the vessels, inducing a large spill-out effect [33], the signal was corrected for this spill-out effect using the geometric transfer matrix approach [34]. 1 For each group, the extracted signal was then corrected using the corresponding mean Finally, the Vt map was normalized into the MNI space using transformation parameters obtained during structural MRI spatial normalization (2 mm isotropic voxel size).…”

Molecular Imaging of PDE10A Knockout Mice with a Novel PET Radiotracer: [11C]T-773

“…Small animal imaging has the possibility of simultaneous brain and hearth imaging due to the large FOV compared to the body size of some rodent species. This has the possibility to facilitate the application of image derived input function methods similar to the advancements in human research (115), but with the use of the left ventricle instead.…”