(68)Ga-DOTA chelate, a novel imaging agent for assessment of myocardial perfusion and infarction detection in a rodent model

BACKGROUND: Magnetic resonance imaging (MRI) with Gadolinium 1,4,7,10-tetraazacyclododecane-N′,N″,N′′′,N″″-tetraacetic acid (Gd-DOTA) enables assessment of myocardial perfusion during first-pass of the contrast agent, while increased retention can signify areas of myocardial infarction (MI). We studied whether Gallium-68-labeled analog, (68)Ga-DOTA, can be used to assess myocardial perfusion on positron emission tomography/computed tomography (PET/CT) in rats, comparing it with (11)C-acetate. METHODS: Rats were studied with (11)C-acetate and (68)Ga-DOTA at 24 hours after permanent ligation of the left coronary artery or sham operation. One-tissue compartmental models were used to estimate myocardial perfusion in normal and infarcted myocardium. After the PET scan, hearts were sectioned for autoradiographic detection of (68)Ga-DOTA distribution. RESULTS: (11)C-acetate PET showed perfusion defects and histology showed myocardial necrosis in all animals after coronary ligation. Kinetic modeling of (68)Ga-DOTA showed significantly higher k(1) values in normal myocardium than in infarcted areas. There was a significant correlation (r = 0.82, P = 0.001) between k(1) values obtained with (68)Ga-DOTA and (11)C-acetate. After 10 minutes of tracer distribution, the (68)Ga-DOTA concentration was significantly higher in the infarcted than normal myocardium on PET imaging and autoradiography. CONCLUSIONS: Our results indicate that acute MI can be detected as reduced perfusion, as well as increased late retention of (68)Ga-DOTA. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s12350-019-01752-6) contains supplementary material, which is available to authorized users.