Image derived input functions for dynamic High Resolution Research Tomograph PET brain studies

Self Cite

The aim of this study was to validate in vivo the accuracy of a reconstruction-based partial volume correction (PVC), which takes into account the point spread function of the imaging system. The NEMA NU2 Image Quality phantom and five healthy volunteers (using [ 11 C]flumazenil) were scanned on both HR + and high-resolution research tomograph (HRRT) scanners. HR + data were reconstructed using normalization and attenuation-weighted ordered subsets expectation maximization (NAW-OSEM) and a PVC algorithm (PVC-NAW-OSEM). HRRT data were reconstructed using 3D ordinary Poisson OSEM (OP-OSEM) and a PVC algorithm (PVC-OP-OSEM). For clinical studies, parametric volume of distribution (V T ) images were generated. For phantom data, good recovery was found for both OP-OSEM (0.84 to 0.97) and PVC-OP-OSEM (0.91 to 0.98) HRRT reconstructions. In addition, for the HR + , good recovery was found for PVC-NAW-OSEM (0.84 to 0.94), corresponding well with OP-OSEM. Finally, for clinical data, good correspondence was found between PVC-NAW-OSEM and OP-OSEM-derived V T values (slope: 1.02 ± 0.08). This study showed that HR + image resolution using PVC-NAW-OSEM was comparable to that of the HRRT scanner. As the HRRT has a higher intrinsic resolution, this agreement validates reconstruction-based PVC as a means of improving the spatial resolution of the HR + scanner and thereby improving the quantitative accuracy of positron emission tomography.

Section: Phantom Studysupporting

confidence: 90%

In vivo Validation of Reconstruction-Based Resolution Recovery for Human Brain Studies

Mourik

Lubberink

Velden

et al. 2009

Self Cite

“…This becomes particularly challenging with radioligands with fast metabolism such as [carbonyl-11 C]WAY-100635, which typically displays small area under the tail of the blood curve. 32 Previous studies have shown that Chen's approach can be successfully applied to the radioligands 29 applied their method to [ 11 C]flumazenil data acquired with the HRRT, they found good correspondence between MIF and IDIF using 16 iterations (compared with 10 in the present study). We have previously shown, using the NEMA phantom, that for a volume of 10 mm diameter, increasing the number of iterations from 10 to 16 has negligible effect on the recovery, 9 whereas the noise level and reconstruction time are increased.…”

Section: Discussionsupporting

confidence: 62%

“…Mourik's method relies on optimal reconstruction settings for HRRT data. 29 To assess the clinical applicability, the standard reconstruction setting normally applied to HRRT data at Karolinska Institutet was used (see section Subjects and Positron Emission Tomography Measurements). To delineate ROIs for the carotids, a summation image of the early frames was smoothed, after which the 4 hottest pixels in 16 planes below the circle of willis were identified, as described as optimal ROI volume for the HRRT data.…”

Section: Methods For Image-derived Input Functionmentioning

confidence: 99%

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

Schain

Benjaminsson

Varnäs

et al. 2013

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.

“…Calibration greatly improved the estimation of the CMRglc values (score: 8). Mourik et al (2008aMourik et al ( , 2009 (Mourik et al, 2008b). This suggests that the necessity of calibrating the IF estimated with this method should be carefully assessed for each tracer and for each machine.…”

Section: Discussionmentioning

confidence: 99%

Comparison of Eight Methods for the Estimation of the Image-Derived Input Function in Dynamic [¹⁸F]-FDG PET Human Brain Studies

Zanotti‐Fregonara

Fadaili

Maroy

et al. 2009

The aim of this study was to compare eight methods for the estimation of the image-derived input function (IDIF) in [ 18 F]-FDG positron emission tomography (PET) dynamic brain studies. The methods were tested on two digital phantoms and on four healthy volunteers. Image-derived input functions obtained with each method were compared with the reference input functions, that is, the activity in the carotid labels of the phantoms and arterial blood samples for the volunteers, in terms of visual inspection, areas under the curve, cerebral metabolic rates of glucose (CMRglc), and individual rate constants. Blood-sample-free methods provided less reliable results as compared with those obtained using the methods that require the use of blood samples. For some of the bloodsample-free methods, CMRglc estimations considerably improved when the IDIF was calibrated with a single blood sample. Only one of the methods tested in this study, and only in phantom studies, allowed a reliable calculation of the individual rate constants. For the estimation of CMRglc values using an IDIF in [ 18 F]-FDG PET brain studies, a reliable absolute blood-sample-free procedure is not available yet.