Automatic extraction of forward stroke volume using dynamic PET/CT: a dual-tracer and dual-scanner validation in patients with heart valve disease.
BACKGROUND
The aim of this study was to develop and validate an automated method for extracting forward stroke volume (FSV) using indicator dilution theory directly from dynamic positron emission tomography (PET) studies for two different tracers and scanners.


METHODS
35 subjects underwent a dynamic (11)C-acetate PET scan on a Siemens Biograph TruePoint-64 PET/CT (scanner I). In addition, 10 subjects underwent both dynamic (15)O-water PET and (11)C-acetate PET scans on a GE Discovery-ST PET/CT (scanner II). The left ventricular (LV)-aortic time-activity curve (TAC) was extracted automatically from PET data using cluster analysis. The first-pass peak was isolated by automatic extrapolation of the downslope of the TAC. FSV was calculated as the injected dose divided by the product of heart rate and the area under the curve of the first-pass peak. Gold standard FSV was measured using phase-contrast cardiovascular magnetic resonance (CMR).


RESULTS
FSVPET correlated highly with FSVCMR (r = 0.87, slope = 0.90 for scanner I, r = 0.87, slope = 1.65, and r = 0.85, slope = 1.69 for scanner II for (15)O-water and (11)C-acetate, respectively) although a systematic bias was observed for both scanners (p < 0.001 for all). FSV based on (11)C-acetate and (15)O-water correlated highly (r = 0.99, slope = 1.03) with no significant difference between FSV estimates (p = 0.14).


CONCLUSIONS
FSV can be obtained automatically using dynamic PET/CT and cluster analysis. Results are almost identical for (11)C-acetate and (15)O-water. A scanner-dependent bias was observed, and a scanner calibration factor is required for multi-scanner studies. Generalization of the method to other tracers and scanners requires further validation.
Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark. hans.harms@clin.au.dk.
Hendrik Johannes
HJ
Harms
Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark. Lars.tolbod@aarhus.rm.dk.
Lars Poulsen
LP
Tolbod
Department of Cardiology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark. nilshans@rm.dk.
Nils Henrik Stubkjær
NH
Hansson
Departments of Nuclear Medicine & PET, Uppsala University, Akademiska Sjukhuset, 751 85, Uppsala, Sweden. tanja.kero@radiol.uu.se.
Tanja
T
Kero
Department of Cardiology, Uppsala University, Akademiska Sjukhuset, 751 85, Uppsala, Sweden. lovisa.holm.orndahl@akademiska.se.
Lovisa Holm
LH
Orndahl
Department of Cardiology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark. yong.kim@ki.au.dk.
Won Yong
WY
Kim
Department of Radiology, Uppsala University, Akademiska Sjukhuset, 751 85, Uppsala, Sweden. Tomas.bjerner@radiol.uu.se.
Tomas
T
Bjerner
Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark. kirsbouc@rm.dk.
Kirsten
K
Bouchelouche
Department of Cardiology, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark. henrikwiggers@dadlnet.dk.
Henrik
H
Wiggers
Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark. jf@clin.au.dk.
Jørgen
J
Frøkiær
Department of Nuclear Medicine & PET Centre, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark. jens.sorensen@pet.uu.se.|Departments of Nuclear Medicine & PET, Uppsala University, Akademiska Sjukhuset, 751 85, Uppsala, Sweden. jens.sorensen@pet.uu.se.
Jens
J
Sörensen
Dynamic imaging; Positron emission tomography; Stroke volume