Original ArticleEffect of temporal sampling protocols on myocardial blood flow measurements using Rubidium-82 PET
Introduction
Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) using Rubidium-82 (Rb-82) PET is increasingly used in daily clinical practice. It provides valuable prognostic information in addition to the visual evaluation of myocardial perfusion imaging (MPI) PET data in the detection and evaluation of coronary artery disease (CAD).1, 2, 3, 4, 5 The increasing use of MBF and MFR quantification among multiple hospitals performing Rb-82 PET MPI and the lack of consensus in literature and guidelines on reconstruction protocols has led to a wide variety of temporal sampling protocols that could limit accuracy and data comparison between centers.6,7
A temporal sampling protocol is used to reconstruct dynamic images. These dynamic images are then used to determine the tracer activity concentration in the blood pool (left ventricle (LV)) and myocardial tissue over time in order to quantify MBF and MFR.3 It is important that these measurements are accurate as the resulting time–activity curves (TACs) are used as input for compartmental analysis to calculate the MBF.3,8,9 Both the length and the number of time frames in the temporal sampling protocol may influence the measured TACs and may therefore alter MBF and MFR measurements.10 In order to interchange and interpret MBF and MFR values across different centers, it is important to know the effect of temporal sampling on absolute MBF and MFR measurements. Therefore, our aim was to assess the effect of various clinically used temporal sampling protocols on MBF and MFR quantification.
Section snippets
Temporal Sampling Protocol Selection
A literature search was performed using the Scopus database to find articles available in September 2020. The search strategy to identify all possible temporal sampling protocols used in clinical practice involved the use of the following terms in the title, keywords or abstract: “Rubidium” or “Rb,” and “myocardial blood flow” or “MBF” or “flow,” and “quantification” or “sampling” or “dynamic” or “time frame” or “frame time,” and not “dog” or “canine” or “rabbit,” or “animal.” The full texts of
Results
We screened 112 articles finding 62 potentially relevant articles containing temporal sampling protocols, as shown in Figure 2. Upon additional review, this resulted in 15 different temporal sampling protocols that were applied to patient data, including the reference protocol referred by 26A, as shown in Table 1 and Figure 3. The baseline characteristics of the included patients are summarized in Table 2.
We found a good reproducibility for the reference protocol as the mean absolute relative
Discussion
In this study, we selected temporal sampling protocols used in Rb-82 PET MPI from the literature and assessed the effect on absolute blood flow measurements. We showed that the use of various temporal sampling protocols can result in different rest and stress MBF, both on a regional and global level. We found mean absolute relative differences up to 13% for global MBF and up to 16% for regional MBF in comparison to the reference protocol. No significant differences were found for global or
New Knowledge Gained
This manuscript provides new insights and has several clinical consequences. First, one should be cautious in using different temporal sampling protocols in PET imaging as we found significant differences for rest and stress MBF measurements in the myocardium as a whole but also on a regional level. It seems that MFR is less dependent on temporal sampling (this study) and also on other technical variations.19, 20, 21 Therefore, MFR seems to be a more suitable parameter to be used between
Conclusions
Various temporal sampling protocols for MBF and MFR quantification using Rb-82 PET result in different MBF values. MFR measurements were more robust to different temporal sampling protocols. Hence, we recommend using MFR instead of MBF measurements, especially when employed at different centers and in multicenter trials.
Disclosures
None of the authors have anything to disclose.
Funding
The authors have not received funding for the present study.
References (30)
- et al.
Impaired myocardial flow reserve on rubidium-82 positron emission tomography imaging predicts adverse outcomes in patients assessed for myocardial ischemia
Cardiac Imaging
(2011) - et al.
Clinical quantification of myocardial blood flow using PET: Joint position paper of the SNMMI cardiovascular council and the ASNC
J Nucl Cardiol
(2018) - et al.
Time-frame sampling for 82Rb PET flow quantification: Towards standardization of clinical protocols
J Nucl Cardiol
(2017) - et al.
Quantification of myocardial blood flow and flow reserve: Technical aspects
J Nucl Cardiol
(2010) - et al.
Precision and accuracy of clinical quantification of myocardial blood flow by dynamic PET: A technical perspective
J Nucl Cardiol
(2015) - et al.
Optimization of temporal sampling for 82rubidium PET myocardial blood flow quantification
J Nucl Cardiol
(2017) - et al.
How to detect and correct myocardial creep in myocardial perfusion imaging using rubidium-82 PET?
J Nucl Cardiol
(2019) - et al.
Impact of regadenoson-induced myocardial creep on dynamic rubidium-82 PET myocardial blood flow quantification
J Nucl Cardiol
(2019) - et al.
Quantitative assessment of myocardial perfusion in the detection of significant coronary artery disease cutoff values and diagnostic accuracy of quantitative [O-15]H2O PET imaging
J Am Coll Cardiol
(2014) - et al.
Comparison of positron emission tomography measurement of adenosine-stimulated absolute myocardial blood flow versus relative myocardial tracer content for physiological assessment of coronary artery stenosis severity and location
JACC Cardiovasc Imaging
(2009)
Impact of point spread function modeling and time-of-flight on myocardial blood flow and myocardial flow reserve measurements for rubidium-82 cardiac PET
J Nucl Cardiol
Comparison of maximal rubidium-82 activities for myocardial blood flow quantification between digital and conventional PET systems
J Nucl Cardiol
Generator-produced rubidium-82 positron emission tomography myocardial perfusion imaging—From basic aspects to clinical applications
J Cardiol
Regadenoson versus dipyridamole hyperemia for cardiac PET imaging
JACC Cardiovasc Imaging
Clinical use of quantitative cardiac perfusion PET: Rationale, modalities and possible indications. Position paper of the cardiovascular committee of the European association of nuclear medicine (EANM)
Eur J Nucl Med Mol Imaging
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