RT Journal Article
SR Electronic
T1 Residual activity correction for computing myocardial blood flow from dynamic <sup>13</sup>NH<sub>3</sub> studies
JF Journal of Nuclear Medicine
JO J Nucl Med
FD Society of Nuclear Medicine
SP 2103
OP 2103
VO 52
IS supplement 1
A1 Pan, Xiao-Bo
A1 Alexanderson, Erick
A1 Le Meunier, Ludovic
A1 Declerck, Jerome
YR 2011
UL http://jnm.snmjournals.org/content/52/supplement_1/2103.abstract
AB 2103 Objectives A cardiac perfusion PET study requires at least 2 scans (rest and stress). With 13NH3 (half life of 9.97min), some residual activity from the previous study could still be present in the subsequent scan, potentially introducing overestimation in the quantification of the myocardial blood flow (MBF) [1]. A method to estimate and correct the residual activity for computing MBF is presented. Methods 24 patient rest and adenosine stress 13NH3 datasets were obtained on a Siemens Biograph-64 PET/CT scanner. The acquisition of the stress scan started before the injection, so that the first frame of the dynamic sequence only contains residual activity from the rest. 16 frames (12x10s, 2x30s, 1x60s, 1x360s) were reconstructed. The residual activity is quantified using the value of the blood input function (BIF) and time activity curve (TAC) on the first frame, and corrected by subtracting it from all frames of the TACs and BIF. MBF and CFR values are computed using Siemens syngo.MBF software. Results The time interval between the rest and stress injection is between 19 and 40 min. The mean (±SD) stress flow with and without residual correction is 2.09 ± 0.61 and 2.3 ± 0.65 ml/g/min, with correlation coefficient R2 = 0.969, slope = 0.93, intercept = -0.05. The ratio of MBF with and without residual correction is 90.7% ± 4.9%. The mean first frame residual activity in the myocardium varies between 1,993 to 19,967 Bq/ml. Conclusions Residual activities in the consecutive 13NH3 studies introduce some overestimation of MBF. A first frame subtraction method is shown to correct the residual activity successfully for computing MBF