Scott Leonard

Single photon-emission computed tomography

The current document is an update of an earlier version of single photon emission tomography (SPECT) guidelines that was developed by the American Society of Nuclear Cardiology. Although that document was only published a few years ago, there have been significant advances in camera technology, imaging protocols, and reconstruction algorithms that prompted the need for a revised document. This publication is designed to provide imaging guidelines for physicians and technologists who are qualified to practice nuclear cardiology. While the information supplied in this document has been carefully reviewed by experts in the field, the document should not be considered medical advice or a professional service. We are cognizant that SPECT technology is evolving rapidly and that these recommendations may need further revision in the near future. Hence, the imaging guidelines described in this publication should not be used in clinical studies until they have been reviewed and approved by qualified physicians and technologists from their own particular institutions. 2. INSTRUMENTATION QUALITY ASSURANCE AND PERFORMANCE

Reproducible measurements based on Myocardial Perfusion Studies for patient follow-up

Our aim is to derive quantitative measurements from Myocardium Perfusion Scintigraphic (MPS) exams for drug trials on Myocardium re-perfusion. We are considering 19 patients imaged 6 times to measure the effects of various conditions of SPECT acquisition (Sestamibi stress and Thallium rest). We are also measuring the stability of various indices of perfusion evolution. Our method is based on intra-patients image matching techniques for follow-up and on inter-patients matching with a reference model based on 100 normal subjects to define perfusion abnormalities. We are measuring intensity differences between normalized images of 10% for Sestamibi and 14% for Thallium. Correlation between image acquisitions is 95% for Sestamibi and 88% for Thallium. Our most stable index is the deficit load, being the integral over stress defects of perfusion deficit. For our 19 cases, deficit load average is 8% of global normal perfusion (GNP), standard deviation between 2 acquisitions is about 0.5% GNP with a -0.4% GNP systematic bias, and correlation between 2 acquisitions is 99.8%. The stability of the index is demonstrated and we expect that a deficit load variation of more than 2% GNP is significant of an evolution, which has to be confirmed by ongoing retrospective drug trials.