Comparison of methods for quantification of rCBF on the HRRT PET scanner using [15O]H2O

• Main Authors: Walker, M D, Feldmann, M, Koepp, M J, Anton-Rodriguez, J M, Shaonan Wang, Matthews, J C, Asselin, Marie-Claude
• Format: Conference Proceeding
• Language: English
• Subjects: Image reconstruction; Noise; Positron emission tomography; Smoothing methods; Spatial resolution; Three dimensional displays
• ISSN: 1082-3654; 2577-0829
• DOI: 10.1109/NSSMIC.2010.5874340

The current study aimed to derive accurate estimates of regional cerebral blood flow (rCBF) from noisy dynamic [ 15 O]H 2 O PET images acquired on the High Resolution Research Tomograph (HRRT), whilst retaining the high spatial resolution of this scanner (2-3 mm) in parametric images. We compared the PET autoradiographic and the generalised linear least squares (GLLS) methods to the non-linear least squares (NLLS) method for rCBF estimation. Six healthy volunteers underwent two [ 15 O]H 2 O PET scans which included continuous arterial blood sampling. rCBF estimates were obtained from different methods of image reconstruction: 3DRP, OP-OSEM, and RM-OP-OSEM which includes a resolution model. A range of filters (3D Gaussian, 0-6 mm FWHM) were considered, as were a range of accumulation times (40-120 s) in the case of the autoradiographic method. Whole-brain rCBF values were found to be relatively insensitive to the method of reconstruction and rCBF quantification. The average whole-brain gray matter (GM) rCBF for 3DRP reconstruction and NLLS was 0.44±0.03 mL min cm -3 , in agreement with literature values. Similar values were obtained from other methods. For generation of parametric images using GLLS or the autoradiographic method, a filter of ≥4 mm was required in order to suppress noise in the PET images which can otherwise produce large biases in the rCBF estimates.