Coronary calcium score scans for attenuation correction of quantitative PET/CT 13N-ammonia myocardial perfusion imaging.
OBJECTIVE
The aim of this study was to evaluate whether ECG-triggered coronary calcium scoring (CCS) scans can be used for attenuation correction (AC) to quantify myocardial blood flow (MBF) and coronary flow reserve (CFR) assessed by PET/CT with (13)N-ammonia.


METHODS
Thirty-five consecutive patients underwent a (13)N-ammonia PET/CT scan at rest and during standard adenosine stress. MBF values were calculated using AC maps obtained from the ECG-triggered CCS scan during inspiration and validated against MBF values calculated using standard non-gated transmission scans for AC. CFR was calculated as the ratio of hyperaemic over resting MBF. In all 35 consecutive patients intraobserver variability was assessed by blinded repeat analysis for both AC methods.


RESULTS
There was an excellent correlation between CT AC and CCS for global MBF values at rest (n = 35, r = 0.94, p < 0.001) and during stress (n = 35, r = 0.97, p < 0.001) with narrow Bland-Altman (BA) limits of agreement (-0.21 to 0.10 ml/min per g and -0.41 to 0.30 ml/min per g) as well as for global CFR (n = 35, r = 0.96, p < 0.001, BA -0.27 to 0.34). The excellent correlation was preserved on the segmental MBF analysis for both rest and stress (n = 1190, r = 0.93, p < 0.001, BA -0.60 to 0.50) and for CFR (n = 595, r = 0.87, p < 0.001, BA -0.71 to 0.74). In addition, reproducibility proved excellent for global CFR by CT AC (n = 35, r = 0.91, p < 0.001, BA -0.42-0.58) and CCS scans (n = 35, r = 0.94, p < 0.001, BA -0.34-0.45).


CONCLUSIONS
Use of attenuation maps from CCS scans allows accurate quantitative MBF and CFR assessment with (13)N-ammonia PET/CT.
Cardiac Imaging, University Hospital Zurich, NUK C42, Ramistrasse 100, 8091, Zurich, Switzerland.
Nina
N
Burkhard
Bernhard A
BA
Herzog
Lars
L
Husmann
Aju P
AP
Pazhenkottil
Irene A
IA
Burger
Ronny R
RR
Buechel
Ines
I
Valenta
Christophe A
CA
Wyss
Philipp A
PA
Kaufmann
D000368:Aged; D000369:Aged, 80 and over; D000641:Ammonia / Q000737:chemistry; D002118:Calcium / Q000378:metabolism*; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000378:metabolism*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging; D009590:Nitrogen Radioisotopes / Q000737:chemistry; D049268:Positron-Emission Tomography; D014057:Tomography, X-Ray Computed
D009590:Nitrogen Radioisotopes; D000641:Ammonia; D002118:Calcium