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Nuklearmedizin 1987; 26(06): 241-247
DOI: 10.1055/s-0038-1628897
Review Articles
Schattauer GmbH

Analysis of Myocardial Time-Activity Curves of 123I-Heptadecanoic Acid I. Curve Fitting

M. J. van Eenige
*   From the Department of Cardiology, Switzerland
,
F. C. Visser
*   From the Department of Cardiology, Switzerland
,
C. M. B. Duwel
*   From the Department of Cardiology, Switzerland
,
P. D. Bezemer
**   Department of Cardiology Statistics, Switzerland
,
G. Westera
***   Free University Amsterdam, The Netherlands, and Universitätsspital Zürich, Switzerland
,
A. J. P. Karreman
*   From the Department of Cardiology, Switzerland
,
J. P. Roos
*   From the Department of Cardiology, Switzerland
› Author Affiliations
Further Information

Publication History

Received: 16 March 1987

Publication Date:
05 February 2018 (online)

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Myocardial time-activity curves can be described by two or more parameters. To establish the optimal curve fitting method 33 myocardial time-activity curves were analyzed with different curve fitting methods: monoexponential, biexponential and monoexponential plus constant. A background correction was not applied. Biexponential curve fitting resulted in redundancy of parameters. Optimal curve fitting was obtained with monoexponential plus constant. The constant represents the background activity together with the stored radiolabelled lipids and the half-time value represents the wash-out of radioiodide from the myocardium. A strong relation was found between the constant and the half-time value: small errors in the determination of the constant (background activity) resulted in considerable errors of the half-time value. It is concluded that optimal analysis of a myocardial time-activity curve can be performed with a monoexponential plus constant without earlier correction for background activity.

Zusammenfassung

Der myokardiale Zeitaktivitätsverlauf kann durch zwei oder mehr Parameter beschrieben werden. Um die optimale Kurvenbeschreibung zu finden, wurden 33 myokardiale Zeitaktivitätskurven mit verschiedenen Kurvenfitmethoden analysiert: monoexponential, biexponential und monoexponential plus Konstante. Eine Untergrundkorrektur wurde nicht angewandt. Der biexponentiale Kurvenfit resultierte in überzähligen Parametern. Ein optimaler Kurvenfit wurde monoexponential plus Konstante erreicht. Die Konstante repräsentiert die Untergrundaktivität zusammen mit den gespeicherten radiomarkierten Fetten. Die Halbwertszeit repräsentiert die Clearance von Jodiden aus dem Myokard. Eine feste Beziehung wurde zwischen Konstante und Halbwertszeit gefunden: kleine Fehler in der Berechnung der Konstante resultierten in bedeutenden Fehlern der Halbwertszeit. Die optimale Analyse einer myokardialen Zeitaktivitätskurve wird mit einem monoexponentialen Fit plus Konstante ohne vorhergehende Untergrundkorrektur erreicht.

 

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