Quantitative effects of contrast enhanced CT attenuation correction on PET SUV measurements.
OBJECTIVE
The presence of contrast materials on computed tomography (CT) images can cause problems in the attenuation correction of positron emission tomography (PET) images. These are because of errors converting the CT attenuation of contrast to 511-keV attenuation and by the change in tissue enhancement over the duration of the PET emission scan. Newer CT-based attenuation correction (CTAC) algorithms have been developed to reduce these errors.


METHODS
To evaluate the effectiveness of the modified CTAC technique, we performed a retrospective analysis on 20 patients, comparing PET images using unenhanced and contrast-enhanced CT scans for attenuation correction. A phantom study was performed to simulate the effects of contrast on radiotracer concentration measurements.


RESULTS
There was a maximum difference in calculated radiotracer concentrations of 5.9% within the retrospective data and 7% within the phantom data.


CONCLUSIONS
Using a CTAC algorithm that de-emphasizes high-density areas, contrast-enhanced CT can be used for attenuation mapping without significant errors in quantitation.
Bunyaviroch
Tira
T
Department of Radiology, Nuclear Medicine Section, Duke University Medical Center, Durham, NC 27710, USA. tbunyaviroch@hotmail.com
Turkington
Timothy G
TG
Wong
Terence Z
TZ
Wilson
John W
JW
Colsher
James G
JG
Coleman
R Edward
RE
D000465:Algorithms; D003287:Contrast Media / Q000493:pharmacokinetics*; D006801:Humans; D019047:Phantoms, Imaging; D049268:Positron-Emission Tomography / Q000295:instrumentation / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*
D003287:Contrast Media