PT - JOURNAL ARTICLE AU - Tiziano Schepis AU - Oliver Gaemperli AU - Valerie Treyer AU - Ines Valenta AU - Cyrill Burger AU - Pascal Koepfli AU - Mehdi Namdar AU - Itaru Adachi AU - Hatem Alkadhi AU - Philipp A. Kaufmann TI - Absolute Quantification of Myocardial Blood Flow with <sup>13</sup>N-Ammonia and 3-Dimensional PET AID - 10.2967/jnumed.107.044099 DP - 2007 Nov 01 TA - Journal of Nuclear Medicine PG - 1783--1789 VI - 48 IP - 11 4099 - http://jnm.snmjournals.org/content/48/11/1783.short 4100 - http://jnm.snmjournals.org/content/48/11/1783.full SO - J Nucl Med2007 Nov 01; 48 AB - The aim of this study was to compare 2-dimensional (2D) and 3-dimensional (3D) dynamic PET for the absolute quantification of myocardial blood flow (MBF) with 13N-ammonia (13N-NH3). Methods: 2D and 3D MBF measurements were collected from 21 patients undergoing cardiac evaluation at rest (n = 14) and during standard adenosine stress (n = 7). A lutetium yttrium oxyorthosilicate–based PET/CT system with retractable septa, enabling the sequential acquisition of 2D and 3D images within the same patient and study, was used. All 2D studies were performed by injecting 700–900 MBq of 13N-NH3. For 14 patients, 3D studies were performed with the same injected 13N-NH3 dose as that used in 2D studies. For the remaining 7 patients, 3D images were acquired with a lower dose of 13N-NH3, that is, 500 MBq. 2D images reconstructed by use of filtered backprojection (FBP) provided the reference standard for MBF measurements. 3D images were reconstructed by use of Fourier rebinning (FORE) with FBP (FORE–FBP), FORE with ordered-subsets expectation maximization (FORE–OSEM), and a reprojection algorithm (RP). Results: Global MBF measurements derived from 3D PET with FORE–FBP (r = 0.97), FORE–OSEM (r = 0.97), and RP (r = 0.97) were well correlated with those derived from 2D FBP (all Ps &lt; 0.0001). The mean ± SD differences in global MBF measurements between 3D FORE–FBP and 2D FBP and between 3D FORE–OSEM and 2D FBP were 0.01 ± 0.14 and 0.01 ± 0.15 mL/min/g, respectively. The mean ± SD difference in global MBF measurements between 3D RP and 2D FBP was 0.00 ± 0.16 mL/min/g. The best correlation between 2D PET and 3D PET performed with the lower injected activity was found for the 3D FORE–FBP reconstruction algorithm (r = 0.95, P &lt; 0.001). Conclusion: For this scanner type, quantitative measurements of MBF with 3D PET and 13N-NH3 were in excellent agreement with those obtained with the 2D technique, even when a lower activity was injected.