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Feasibility of myocardial perfusion imaging with half the radiation dose in obese patients using ordered-subset
Nili Zafrir1, Tamir Bental, Alejandro Solodky
1Nuclear Cardiology Unit, Department of Cardiology, Rabin Medical Center, Beilinson Campus, 49100 Petah Tikva, Israel. zafrirmd@isdn.net.il
Background:
We previously described the feasibility of myocardial perfusion imaging (MPI) with nearly half the radiation dose using ordered-subset expectation maximization with resolution recovery (OSEM-RR) processing. This study sought to determine if the findings can be expanded to obese patients.
Methods:
Fifty obese patients (>100 kg) referred for MPI underwent stress-rest or rest-stress studies with a half dose of Tc-99m sestamibi in a 1-day protocol using OSEM-RR processing. Image quality and clinical results were compared with matched patients (by age, sex, weight, presence/probability of coronary artery disease) evaluated with standard "full-dose" Tc-99m sestamibi, mostly in a 2-day protocol. Dose activities were adjusted individually by weight.
Results:
Mean Tc-99m activity was 33.4 ± 13.9 mCi in the half-dose group and 60 ± 10 mCi in the full-dose group (P < .0001). Respective mean effective doses per study were 10 ± 4 and 18 ± 3 mSv (P < .0001). Overall image quality was good-to-excellent in 94% of the half-dose group and 80% of the full-dose group (P < .045). There was no between-group difference in rate or size of ischemia or infarction, except for stress left ventricular ejection fraction.
Conclusions:
MPI with half the radiation dose is feasible in obese patients. Image quality is better than for full-dose MPI, and the procedure can be performed in 1 day.
Insights
Myocardial perfusion imaging (MPI) is feasible in obese patients with half the radiation dose. This reduced-dose approach offers improved image quality and a shorter 1-day protocol compared to standard full-dose MPI.
Area of Science:
- Cardiology
- Nuclear Medicine
- Radiology
Background:
- Previous studies established the feasibility of reduced-dose myocardial perfusion imaging (MPI) using ordered-subset expectation maximization with resolution recovery (OSEM-RR).
- This research aimed to validate these findings in obese patient populations.
Purpose of the Study:
- To assess the feasibility and efficacy of a half-radiation dose MPI protocol in obese patients.
- To compare image quality and clinical outcomes between reduced-dose and standard full-dose MPI in this cohort.
Main Methods:
- Fifty obese patients underwent a 1-day, half-dose Tc-99m sestamibi MPI protocol with OSEM-RR processing.
- Image quality and clinical results were compared to matched patients who received standard full-dose MPI, often over a 2-day protocol.
- Dose activities were adjusted based on individual patient weight.
Main Results:
- The half-dose group received significantly lower mean Tc-99m activity (33.4 mCi) and had lower effective doses (10 mSv) compared to the full-dose group (60 mCi, 18 mSv).
- Overall image quality was rated good-to-excellent in 94% of the half-dose group versus 80% in the full-dose group (P < .045).
- No significant differences were observed in the rate or size of ischemia or infarction between groups, except for stress left ventricular ejection fraction.
Conclusions:
- Myocardial perfusion imaging with half the radiation dose is feasible and effective in obese patients.
- The reduced-dose protocol demonstrates superior image quality and can be completed within a single day.
- This approach offers a promising alternative for radiation dose reduction in MPI for obese individuals.