Normal Databases for the Relative Quantification of Myocardial Perfusion

Abstract

Purpose of review Myocardial perfusion imaging (MPI) with SPECT is performed clinically worldwide to detect and monitor coronary artery disease (CAD). MPI allows an objective quantification of myocardial perfusion at stress and rest. This established technique relies on normal databases to compare patient scans against reference normal limits. In this review, we aim to introduce the process of MPI quantification with normal databases and describe the associated perfusion quantitative measures that are used. Recent findings New equipment and new software reconstruction algorithms have been introduced which require the development of new normal limits. The appearance and regional count variations of normal MPI scan may differ between these new scanners and standard Anger cameras. Therefore, these new systems may require the determination of new normal limits to achieve optimal accuracy in relative myocardial perfusion quantification. Accurate diagnostic and prognostic results rivaling those obtained by expert readers can be obtained by this widely used technique. Summary Throughout this review, we emphasize the importance of the different normal databases and the need for specific databases relative to distinct imaging procedures. use of appropriate normal limits allows optimal quantification of MPI by taking into account subtle image differences due to the hardware and software used, and the population studied.

Single Photon Emission Computed Tomography (SPECT) Myocardial Perfusion Imaging Guidelines: Instrumentation, Acquisition, Processing, and Interpretation

“…It is customary to use separate, normal databases specific to the imaging camera, the reconstruction method, the patient's gender, as well as the perfusion agent used. 119 This quantitative analysis is typically displayed as a ''bullseye'' or polar plot. The quantitative programs are effective in providing an objective interpretation that is inherently more reproducible than visual analysis, eliminates the variability of the appearance of a defect when viewed in different media (with different radiotracers) and different translation tables, and is particularly helpful identifying subtle changes between two studies in the same patient.…”

The long way to dose reduction in myocardial perfusion imaging

“…Thus, a potential limitation of this quantitative approach is the need for system-specific, protocol-specific, dose-specific, and gender-specific databases of normality. 18 Very recently, different studies have shown that to compare data from the analysis of polar maps across different systems or different configuration of the same system will require the adoption of specific databases of normality, developed for each system and reconstruction method employed. 19,20 On the contrary, if the database of normality should be specific also for the dose level of the study is still an open question today.…”

Factors affecting appearance of a normal myocardial perfusion scan

“…In the recent review of quantification with normal limits, Rubeaux et al summarized the developments with regards to specific normal limits related to the new equipment and imaging protocols. 9 The key parameters defining the characteristics of the normal database are the camera type, count level (low-dose vs high-dose affecting the variation of the normals), 10 attenuation correction (yes/no), patient position (as studied by Kracsko et al), 5,7,8,11,12 and possibly patient ethnicity. For example, an extensive validation of Japanese-specific databases [13][14][15][16] clearly demonstrated the need for the creation of population-specific databases.…”