A biological phantom for contrast-media-based perfusion studies with CT.
OBJECTIVE
Perfusion computed tomography (PCT) is increasingly getting popular with the advent of computed tomography (CT) systems with adequate temporal resolution and spatial coverage. We sought to develop a biological phantom for perfusion measurements in CT to design, improve, and validate scan protocols and postprocessing algorithms in vitro.


METHODS
A special technique was applied to prepare and preserve a fresh porcine kidney. The kidney was connected to an open circuit driven by a peristaltic pump with the option to inject contrast material. We evaluated repeated dynamic contrast-enhanced CT acquisitions with different input flow rates and the relation to calculated parenchymal flow results of the phantom. Flow was calculated with 2 different algorithms. Identical scans were performed with a time interval of 1 year to check long-term stability of the phantom. Different bolus geometries were designed and bolus dispersion was measured for the setup using a tubing array.


RESULTS
We found a linear relationship between the input flow rate of the circuit and the calculated phantom tissue flow with a correlation coefficient rr2 = 0.99 for both algorithms. Both algorithms resulted in very similar absolute values, the mean difference was 3.1 mL/100 mL/min. Perfusion measurements with contrast material injection and storage did not alter the phantom. The enhancement properties did not change over the time of 1 year. With our setup, it was possible to design typical bolus geometries as they occur in clinical practice. Bolus dispersion was small: peak enhancement and bolus width changed by about only 5% over 2-m tube length.


CONCLUSIONS
A phantom for parenchymal flow measurements suitable for repeated measurements over a long period of time was developed. The setup allows the design of diverse bolus geometries with negligible dispersion.
Haberland
Ulrike
U
OncoRay-Center for Radiation Research in Oncology, TU Dresden, Germany. ulrike.haberland.ext@siemens.com
Cordes
Jens
J
Lell
Michael
M
Abolmaali
Nasreddin
N
Klotz
Ernst
E
D000818:Animals; D003287:Contrast Media; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007668:Kidney / Q000000981:diagnostic imaging*; D055420:Perfusion Imaging / Q000295:instrumentation*; D019047:Phantoms, Imaging; D013552:Swine; D014057:Tomography, X-Ray Computed / Q000295:instrumentation*
D003287:Contrast Media