Application of oral contrast media in coregistered positron emission tomography-CT.
OBJECTIVE
Coregistration of positron emission tomography (PET) and CT images results in significantly improved localization of abnormal FDG uptake compared with PET images alone. For delineation of intestinal structures, application of oral contrast media is a standard procedure in CT. The influence of oral contrast agents in PET imaging using CT data for attenuation correction was evaluated in a comparative study on an in-line PET-CT system.


METHODS
Sixty patients referred for PET-CT were evaluated in two groups. One group of 30 patients received oral Gastrografin 45 min before data acquisition. The second group received no contrast medium. PET images were reconstructed, using CT data for attenuation correction. Image analysis was performed by two reviewers in consensus, using a 4-point scale comparing FDG-uptake in the gastrointestinal tract in PET images of both groups. Furthermore, correlation of FDG uptake and localization of contrast media in the intestinal tract in CT images were determined.


RESULTS
No significant difference in FDG uptake in PET images in all regions of the gastrointestinal tract except the ascending colon was seen in both groups. No correlation was found in the location of increased FDG uptake and contrast media in the CT images.


CONCLUSIONS
An oral contrast agent can be used for coregistered PET-CT without the introduction of artifacts in PET.
Department of Medical Radiology, Division of Nuclear Medicine, University Hospital Zurich, Raemistr. 100, CH-8091 Zurich, Switzerland.
Elena V
EV
Dizendorf
Valerie
V
Treyer
Gustav K
GK
Von Schulthess
Thomas F
TF
Hany
D000284:Administration, Oral; D000328:Adult; D000368:Aged; D003287:Contrast Media / Q000008:administration & dosage*; D003974:Diatrizoate Meglumine / Q000008:administration & dosage*; D004064:Digestive System / Q000000981:diagnostic imaging*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D019275:Radiopharmaceuticals; D014055:Tomography, Emission-Computed / Q000295:instrumentation; D014057:Tomography, X-Ray Computed / Q000295:instrumentation
D003287:Contrast Media; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D003974:Diatrizoate Meglumine