Rest and adenosine stress 15O-water PET was performed using a hybrid PET-CT scanner (128-multidetector Biograph mCT, Siemens Medical Systems, Germany), as previously described [20 (link)]. Attenuation correction computed tomography imaging maps was acquired before rest and stress imaging. 15O-water was produced by an on-site cyclotron (PETtrace 8, GE Healthcare, UK) and a radiowater generator (Hydex Oy, Finland) generated the 15O-water bolus. For rest imaging, a target of 500 MBq 15O-water bolus was injected intravenously over 15 s and the venous line was then flushed for another 2 min. The dynamic acquisition was performed over 5 min (14 frames × 5 s, 3 frames × 10 s, 3 frames × 20 and 4 frames × 30 s).
Following suitable radioactivity decay (of approximately 10 min), stress imaging was performed with intravenously administering adenosine for 4 min (140 μg/kg/min, Adenoscan, Sanofi Aventis) [13 (link)], [20 (link)]. The above protocol was then repeated using a further dose of 500 MBq 15O-water bolus. Dynamic emission images were reconstructed using the standard UltraHD algorithm (Siemens Medical Systems, Germany) with a zoom of 2.00, matrix 128 × 128, voxels 3.18 × 3.18 × 3 mm.
Following suitable radioactivity decay (of approximately 10 min), stress imaging was performed with intravenously administering adenosine for 4 min (140 μg/kg/min, Adenoscan, Sanofi Aventis) [13 (link)], [20 (link)]. The above protocol was then repeated using a further dose of 500 MBq 15O-water bolus. Dynamic emission images were reconstructed using the standard UltraHD algorithm (Siemens Medical Systems, Germany) with a zoom of 2.00, matrix 128 × 128, voxels 3.18 × 3.18 × 3 mm.
