Brain-gut axis imaging, motion correction with [ ¹¹ C]-carfentanil total-body PET

Area of Science:

• Neuroscience
• Radiology
• Pharmacology

Background:

• Mu-opioid receptors (MORs) are present in the brain and gastrointestinal (GI) tract.
• Total-body PET imaging offers in vivo evaluation of the MOR brain-GI axis.
• GI tract motion complicates dynamic PET imaging analysis.

Purpose of the Study:

• Establish a methodology for motion correction in dynamic total-body PET imaging of the brain-GI axis.
• Characterize peripheral MORs and provide a framework for semi-automatic PET modeling.
• Quantitatively assess pharmacologic perturbations of the MOR brain-GI axis.

Main Methods:

• Four subjects underwent dynamic [11C]-carfentanil total-body PET scans.
• Semi-automatic motion correction was applied using different reference frames.
• Comparison of semi-automatic and manual motion correction methods.
• Kinetic parameters (K1, VT, VTLogan) were estimated using Logan reference tissue model and compartment modeling.

Main Results:

• Semi-automatic motion correction strongly correlated with manual correction (r>0.7) for kinetic parameters.
• Loperamide significantly decreased GI tract MOR availability (VTLogan) compared to baseline (p<0.05).
• Naloxone reduced brain thalamic MOR availability, as expected; loperamide did not.

Conclusions:

• Semi-automatic motion correction in total-body PET facilitates quantitative characterization of the MOR brain-GI axis.
• This method reduces the analytical burden for dynamic PET studies.
• Enables precise assessment of pharmacologic effects on central and peripheral MORs.