Respiratory gating in cardiac PET: Effects of adenosine and dipyridamole.
Respiratory motion due to breathing during cardiac positron emission tomography (PET) results in spatial blurring and erroneous tracer quantification. Respiratory gating might represent a solution by dividing the PET coincidence dataset into smaller respiratory phase subsets. The aim of our study was to compare the resulting imaging quality by the use of a time-based respiratory gating system in two groups administered either adenosine or dipyridamole as the pharmacological stress agent.



Forty-eight patients were randomized to adenosine or dipyridamole cardiac stress82RB-PET. Respiratory rates and depths were measured by a respiratory gating system in addition to registering actual respiratory rates. Patients undergoing adenosine stress showed a decrease in measured respiratory rate from initial to later scan phase measurements [12.4 (±5.7) vs 5.6 (±4.7) min-1, P < .001] and tended to have a lower frequency of successful respiratory gating compared to dipyridamole (47% vs 71%, P = .12). As a result, imaging quality was superior in the dipyridamole group compared to adenosine.



If respiratory gating is considered for use in cardiac PET, a dipyridamole stress protocol is recommended as it, compared to adenosine, causes a more uniform respiration and results in a higher frequency of successful respiratory gating and thereby superior imaging quality.
Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Section 4011, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen, Denmark.
Martin Lyngby
ML
Lassen
Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Section 4011, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen, Denmark. drrasmussen@hotmail.com.
Thomas
T
Rasmussen
Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Section 4011, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen, Denmark.
Thomas E
TE
Christensen
Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Section 4011, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen, Denmark.
Andreas
A
Kjær
Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Section 4011, Rigshospitalet, University of Copenhagen, Blegdamsvej 9, 2100, Copenhagen, Denmark.
Philip
P
Hasbak
D000241:Adenosine / Q000494:pharmacology*; D000368:Aged; D004176:Dipyridamole / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009038:Motion; D049268:Positron-Emission Tomography / Q000379:methods*; D012119:Respiration / Q000187:drug effects; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*
D004176:Dipyridamole; D000241:Adenosine
Respiratory gating; adenosine; dipyridamole; myocardial perfusion imaging: positron emission tomography