Excerpt

The importance of spatial resolution in myocardial perfusion imaging (MPI) has been continuously emphasized over the years with improvements in both hardware and software advancement for acquisition and processing. These advances and innovations began from changes in acquisition parameters (e.g., collimator design, acquisition & orbit type, and attenuation correction) to utilizing emerging technologies with solid-state detectors in hardware, and from a simple filtered back projection reconstruction to iterative, resolution recovery and scatter correction reconstruction algorithm techniques in software. While these advances mostly apply to SPECT imaging, PET MPI has undergone a steady evolution improving various aspects of imaging as well, including improvements in spatial resolution. Unlike any other organ imaged in nuclear medicine, improving the image resolution in SPECT or PET cardiac imaging still remains challenging due to inherent cardiac contraction, respiratory movement, and patient body motion during the image acquisition. It is especially true with traditional SPECT, where the scan duration is much longer as compared to PET MPI. However, during cardiac PET acquisition, collection of data in list-mode has become available for routine use, allowing for multiple image reconstructions from a single dataset, including static, gated, dynamic, and respiratory-gated images (Fig. 1). In this paper, we review few recent publications and their technical considerations for dual ECG/respiratory-gated cardiac PET imaging in an attempt to recover the spatial resolution loss due to cardiac and respiratory motion.

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