Analysis of myocardial time-activity curves of 123I-heptadecanoic acid. II. The acquisition time.
Optimal fitting of a myocardial time-activity curve is accomplished with a monoexponential plus a constant, resulting in three parameters: amplitude and half-time of the monoexponential and the constant. The aim of this study was to estimate the precision of the calculated parameters. The variability of the parameter values as a function of the acquisition time was studied in 11 patients with cardiac complaints. Of the three parameters the half-time value varied most strongly with the acquisition time. An acquisition time of 80 min was needed to keep the standard deviation of the half-time value within +/- 10%. To estimate the standard deviation of the half-time value as a function of the parameter values, of the noise content of the time-activity curve and of the acquisition time, a model experiment was used. In most cases the SD decreased by 50% if the acquisition time was increased from 60 to 90 min. A low amplitude/constant ratio and a high half-time value result in a high SD of the half-time value. Tables are presented to estimate the SD in a particular case.
Department of Cardiology, Free University, Amsterdam, The Netherlands.
M J
MJ
van Eenige
F C
FC
Visser
A J
AJ
Karreman
C M
CM
Duwel
G
G
Westera
P D
PD
Bezemer
J P
JP
Roos
D003327:Coronary Disease / Q000000981:diagnostic imaging; D005227:Fatty Acids / Q000493:pharmacokinetics*; D006207:Half-Life; D006801:Humans; D007457:Iodine Radioisotopes; D009206:Myocardium / Q000378:metabolism*; D011877:Radionuclide Imaging
D005227:Fatty Acids; D007457:Iodine Radioisotopes; C027252:17-iodoheptadecanoic acid