Novel methods of reconstructing the tracer distribution in myocardial perfusion images are being considered for lowcount and sparse sampling scenarios. Few examples of low count scenarios are when the amount of radioisotope administered or the acquisition time is lowered, in gated studies where individual gates are reconstructed. Examples of sparse angular sampling scenarios are patient motion correction in traditional SPECT where few angles are acquired at any given pose and in multi-pinhole SPECT where the geometry is sparse and truncated by design. The reconstruction method is based on the assumption that the tracer distribution is sparse in the transform domain, which is enforced by a sparsity-promoting penalty on the transform coefficients. In this work we investigated the curvelet transform as the sparse basis for myocardial perfusion SPECT. The objective is to determine if myocardial perfusion images can be efficiently represented in this transform domain, which can then be exploited in a penalized maximum likelihood (PML) reconstruction scheme for improving defect detection in low-count/ sparse sampling scenarios. The performance of this algorithm is compared to standard OSEM with 3D Gaussian post-filtering using bias-variance plots and numerical observer studies. The Channelized Non-prewhitening Observer (CNPW) was used for defect detection task in a “signalknown- statistically” LROC study. Preliminary investigations indicate better bias-variance characteristics and superior CNPW performance with the proposed curvelet basis. However, further assessment using more defect locations and human observer evaluation is needed for clinical significance.

Date Published: 19 March 2013
PDF: 8 pages
Proc. SPIE 8668, Medical Imaging 2013: Physics of Medical Imaging, 86681Y (19 March 2013); doi: 10.1117/12.2007061

Published in SPIE Proceedings Vol. 8668:
Medical Imaging 2013: Physics of Medical Imaging
Robert M. Nishikawa; Bruce R. Whiting; Christoph Hoeschen, Editor(s)