Robust experiment design for estimating myocardial beta adrenergic receptor concentration using PET

Area of Science:

• Nuclear medicine
• Cardiovascular research
• Pharmacology

Background:

• Myocardial beta-adrenergic receptor (beta-AR) concentrations vary significantly in heart failure and volume overload.
• Positron emission tomography (PET) offers noninvasive in vivo estimation of myocardial beta-AR concentration.
• Existing optimal design methods are insufficient for heterogeneous populations.

Purpose of the Study:

• To develop a robust PET experimental protocol for precise myocardial beta-AR estimation in heterogeneous populations.
• To design a two-injection protocol accounting for a wide range of beta-AR concentrations and physiological parameters.
• To ensure reliable beta-AR estimates in both normal and pathological cardiac states.

Main Methods:

• Developed a robust two-injection PET protocol using [18F]-(S)-fluorocarazolol.
• Utilized a synthetic population with diverse beta-AR levels for optimal design.
• Employed a minimax criterion for timing and dosage optimization.
• Validated the protocol in pigs before and after induced beta-AR upregulation.

Main Results:

• The robust PET protocol provided highly precise myocardial beta-AR concentration estimates.
• Noninvasive PET predictions of beta-AR changes after sympathectomy correlated with in vitro assays.
• The designed protocol demonstrated reliability across normal and pathological states.

Conclusions:

• A robust PET experimental design yields reliable myocardial beta-AR estimates in heterogeneous populations.
• This methodology enhances noninvasive assessment of beta-AR in cardiovascular conditions.
• The approach is broadly applicable to parameter estimation in diverse patient groups.