Selection of PET Camera and Implications on the Reliability and Accuracy of Absolute Myocardial Blood Flow Quantification

Abstract

Purpose of Review PET scanner design and performance evaluation has been driven historically by the imaging requirements for whole-body imaging in oncology. Cardiac PET imaging for accurate quantification of myocardial blood flow (MBF) using shortlived tracers such as rubidium-82 imposes additional requirements for wide dynamic range and high count-rate accuracy. This paper examines the technical challenges encountered in cardiac imaging of myocardial perfusion and blood flow quantification. Recent Findings The newest PET-CT scanners using digital silicon photomultiplier technology have high absolute sensitivity (4-20%) and time-of-flight resolution (3-7 cm) which further improves image quality. The concept of "integral" noise equivalent counts (iNEC) is introduced to compare scanner count-rate performance over the wide dynamic range encountered in MBF imaging with rubidium-82. Summary The latest-generation digital PET scanners with wide axial field-of-view and enhanced time-of-flight resolution should enable accurate quantification of MBF, without any compromise in the quality of conventional ECG-gated myocardial perfusion images.

Moving forward with motion reduction, detection and correction in cardiac PET

“…These improvements in image quality actually make motion artifacts more apparent. 1 Consider the analogy that you replace your old standard TV with an ultra-high definition set. With this ultra-high definition now you see more blemishes in the face of your favorite news anchor.…”

“…A more advanced method is one that uses external triggers to select a fraction of the perfusion data that is well registered with the attenuation image. 1 Both these methods suffer from lower count statistics and thus noisy data. Improved methods for correcting for the breathing motion are designed to use all the counts in the entire cardiac PET acquisition.…”