Low radiation dose imaging of myocardial perfusion and coronary angiography with a hybrid PET/CT scanner.
OBJECTIVE
To test the image quality and feasibility of a sequential low radiation dose protocol for hybrid cardiac PET/CT angiography (CTA).


BACKGROUND
Multidetector computed tomography (MDCT) is a non-invasive method for coronary angiography. The negative predictive value of MDCT is high but perfusion imaging has a role in detecting functional significance of coronary lesions. This has encouraged combining these techniques. However, radiation dose is of concern. We report our first experiences with a low dose sequential CTA mode applicable to hybrid imaging.


METHODS
In the first phase, 10 consecutive cardiac MDCT angiographies were performed with spiral acquisition and compared in terms of image quality and dose with the following 10 patients performed with a new sequential mode. In the second phase, feasibility and radiation dose of a combined (15)O-water rest-stress PET perfusion/sequential CTA protocol were assessed in another group of 61 consecutive patients.


RESULTS
Mean effective radiation dose was 60% lower in the sequential group than in the spiral group (19.3 versus 7.6 mSv, P<0.001). In the second phase, the new sequential hybrid protocol proved possible in 87% of the patients given the preconditions determined by the manufacturer. Mean effective dose of the CT acquisition was 7.6 mSv and total dose from the PET/CTA hybrid study 9.5 mSv.


CONCLUSIONS
Low dose PET/CT allows cardiac hybrid studies with <10 mSv. The protocol can be applied to almost nine out of 10 patients with CT image quality comparable to spiral acquisition.
Kajander
S
S
Turku PET Centre, Turku, Finland. sami.kajander@tyks.fi
Ukkonen
H
H
Sipilä
H
H
Teräs
M
M
Knuuti
J
J
D000368:Aged; D017023:Coronary Angiography / Q000295:instrumentation*; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000000981:diagnostic imaging; D004867:Equipment Design; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000295:instrumentation*; D010104:Oxygen Radioisotopes; D049268:Positron-Emission Tomography / Q000295:instrumentation*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D036542:Tomography, Spiral Computed / Q000295:instrumentation; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*
D010104:Oxygen Radioisotopes