PET | Evaluation of Perfusion and Image Quality Changes by Reconstruction Me…

1Yong Ho Do, 1Hong Jae Lee, 1Jin Eui Kim, 1,2Hyung Jun Im, 1,2Jae Sung Lee , 1,2Dong Soo Lee

1Dept. of Nuclear Medicine, Seoul National Univ. Hospital

2Dept. of Nuclear Medicine, Seoul National Univ.

Purpose: The aim of this study was to evaluate changes of quantitative and semi-quantitative myocardial perfusion indices and image quality by image reconstruction methods in 13N- ammonia (13N-NH3) myocardial perfusion PET/CT.

Methods: Data of 14 (8 men, 6 women) patients underwent rest and adenosine stress 13N- NH3 PET/CT (Biograph TruePoint 40 with TrueV, Siemens) were collected. Listmode scans were acquired for 10 minutes by injecting 370MBq of 13N-NH3. Dynamic and static reconstruction was performed by use of FBP, iterative2D (2D), iterative3D (3D) and iterative TrueX (TrueX) algorithm. Coronary flow reserve (CFR) of dynamic reconstruction data, extent(%) and total perfusion deficit (TPD)(%) measured in sum of 4-10 minutes scan were evaluated by comparing with 2D method which was recommended by vendor. The image quality of each reconstructed data was compared and evaluated by five nuclear medicine physicians through a blind test.

Results: CFR were lower in TrueX 18.68% (p=0.0002), FBP 4.35% (p=0.1243) and higher in

3D 7.91% (p<0.0001). As semi-quantitative values, extent and TPD of stress were higher in

3D 3.07%p (p=0.001), 2.36%p (p=0.0002), FBP 1.93%p (p=0.4275), 1.57%p (p=0.4595), TrueX 5.43%p (p=0.0003), 3.93%p (p<0.0001). Extent and TPD of rest were lower in FBP

0.86%p (p=0.1953), 0.57%p (p=0.2053) and higher in 3D 3.21%p (p=0.0006), 2.57%p (p=0.0001) and TrueX 5.36%p (p<0.0001), 4.36%p (p<0.0001). Based on the results of the blind test for image resolution and noise from the snapshot, 3D obtained the highest score, followed by 2D, TrueX and FBP.

Conclusion: We found that quantitative and semi-quantitative myocardial perfusion values could be under- or over-estimated according to  the reconstruction algorithm in 13N-NH3

PET/CT. Therefore, proper dynamic and static reconstruction method should be established to provide accurate myocardial perfusion value.

Keywords: 13N-NH3 PET/CT; CFR; reconstruction method