Absolute quantification of myocardial blood flow with H(2)(15)O and 3-dimensional PET: an experimental validation.
The purpose of this study was to assess a 3-dimensional (3D)-only PET scanner (ECAT EXACT3D) for its use in the absolute quantification of myocardial blood flow (MBF) using H(2)(15)O.


METHODS
Nine large white pigs were scanned with H(2)(15)O and C(15)O before and after partially occluding the circumflex (n = 4) or the left anterior descending (n = 5) coronary artery at rest and during hyperemia induced by intravenous dipyridamole. Radioactive microspheres labeled with either (57)Co or (46)Sc were injected during each of the H(2)(15)O scans, which allowed comparison between microsphere and PET measurements of regional MBF. PET analyses of 3D acquisition data were performed using filtered backprojection reconstruction and region-of-interest definition by factor and cluster analysis techniques and single-compartment model quantification.


RESULTS
The Hanning filter applied in image reconstruction resulted in a left atrial blood volume recovery factor of 0.84 +/- 0.06. Differences between repeated measurements of recovery were small (mean, -0.8%; range, -6.6% to 3.6%). In 256 paired measurements of MBF ranging from 0.05 to 4.4 mL. g(- 1). min(-1), microsphere and PET measurements were fairly well correlated. The mean difference between the 2 methods was - 0.11 mL. g(-1). min(-1) and the limits of agreement (+2 SD) were -0.82 and 0.60 mL. g(-1). min(-1) (Bland-Altman plot).


CONCLUSIONS
Dynamic measurements with H(2)(15)O using a 3D-only PET tomograph provide reliable and accurate measurements of absolute regional MBF over a wide flow range. The 3D acquisition technique can reduce the radiation dose to the subject while maintaining adequate counting statistics.
Schäfers
Klaus P
KP
Medical Research Council Clinical Sciences Centre and National Heart and Lung Institute, Faculty of Medicine, Imperial College of Science, Technology and Medicine, Hammersmith Hospital, London, United Kingdom.
Spinks
Terence J
TJ
Camici
Paolo G
PG
Bloomfield
Peter M
PM
Rhodes
Christopher G
CG
Law
Marilyn P
MP
Baker
Christopher S R
CS
Rimoldi
Ornella
O
D000818:Animals; D003326:Coronary Circulation / Q000502:physiology*; D006321:Heart / Q000000981:diagnostic imaging*; D006940:Hyperemia / Q000000981:diagnostic imaging; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation; D021621:Imaging, Three-Dimensional; D008863:Microspheres; D010104:Oxygen Radioisotopes; D013552:Swine; D014055:Tomography, Emission-Computed / Q000295:instrumentation / Q000379:methods*; D014867:Water
D010104:Oxygen Radioisotopes; D014867:Water