Direct parametric estimation of blood flow in abdominal PET/CT within an EM reconstruction framework

• Published in: IEEE Nuclear Science Symposuim & Medical Imaging Conference pp. 2868 - 2874
• Main Authors: Kotasidis, F A, Reader, A J, Angelis, G I, Markiewicz, P J, Walker, M D, Price, P M, Lionheart, W R, Matthews, J C
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.10.2010
• Subjects: 4-D image reconstruction; Blood; Computed tomography; Direct parametric reconstruction; Image reconstruction; Kinetic theory; perfusion; PET/CT; Positron emission tomography; Reconstruction algorithms; Solid modeling
• ISBN: 9781424491063; 1424491061
• ISSN: 1082-3654; 2577-0829
• DOI: 10.1109/NSSMIC.2010.5874320

Parametric estimation of perfusion using [ 15 O]-H 2 O is an important biomarker for assessing treatment response in oncology clinical trials involving anti-vascular and anti-angiogenic agents. Traditionally the set of dynamic images are reconstructed independently, followed by post-reconstruction kinetic modelling. This methodology results in sub-optimal and often noisy end point parameters if voxel-by-voxel kinetic modelling is used. In [ 15 O]-H 2 O scans, the extremely short temporal frames and the rapid decay of the tracer results in further signal-to-noise ratio (SNR) reduction. Direct 4-D reconstruction methods have the potential to reduce noise and improve parameter estimates by combining image reconstruction and kinetic modelling in a unified process. In this work we implement a direct parametric reconstruction using an EM framework and apply it on a real [ 15 O]-H 2 O PET/CT dataset to derive parametric images of perfusion (f), clearance rate (k 2 ) and fractional blood volume (V a ). Results show substantial variance reduction both in perfusion and k 2 images compared to the post-reconstruction kinetic analysis, especially in areas of increased perfusion. This results in increased tumour-to-background contrast and improved delineation of organ boundaries. Although further analysis in needed, direct reconstruction methods have the potential to be applied in a wide variety of oncology PET/CT studies with the improvements highly depended on the tracer and the system under study.