title: Quantitative effects of contrast enhanced CT attenuation correction on PET SUV measurements.
abstract: 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.
authors: Department of Radiology, Nuclear Medicine Section, Duke University Medical Center, Durham, NC 27710, USA. tbunyaviroch@hotmail.com
authors: Tira
authors: T
authors: Bunyaviroch
authors: Timothy G
authors: TG
authors: Turkington
authors: Terence Z
authors: TZ
authors: Wong
authors: John W
authors: JW
authors: Wilson
authors: James G
authors: JG
authors: Colsher
authors: R Edward
authors: RE
authors: Coleman
mesh_terms: 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*
chemical_list: D003287:Contrast Media