Feasibility of exercise treadmill ¹³N-ammonia positron emission tomography myocardial perfusion imaging using an...

Myocardial perfusion imaging with treadmill exercise nitrogen-13 (¹³N)-ammonia positron emission tomography (PET) presents a logistical challenge. We investigated the feasibility of exercise treadmill (GXT) ¹³N-ammonia PET MPI using an off-site cyclotron for production of ¹³N-ammonia.

Thirty-three patients underwent GXT ¹³N-ammonia PET MPI over 23 months. ¹³N-ammonia doses were prepared at an off-site cyclotron. Patients underwent ¹³N-ammonia resting and ¹³N-ammonia GXT emission and transmission scans at our facility. Image quality, perfusion data, and clinical variables were evaluated.

We analyzed 33 patients (7/26 female/male). Mean age was 63 ± 12 years and mean BMI was 33.7 ± 6.9. GXT PET was feasible in all patients. Image quality was good in 29 patients, adequate in 3, and severely compromised in 1 patient. Summed stress score was 4.5 ± 5.7. Resting and GXT left ventricular ejection fractions were 63.7 ± 10.9% and 66.3 ± 13.1%. TID ratio was 1.0 ± 0.1.

Treadmill exercise ¹³N-ammonia PET is feasible in a large medical center without access to an on-site cyclotron. This technique requires close coordination with an off-site cyclotron but expands the role of PET to patients for whom exercise is more appropriate than pharmacologic stress imaging.