Dual-time-point FDG-PET/CT for the detection of hepatic metastases.
OBJECTIVE
To prove the sensitivity of dual-time-point imaging with 18F-flourodeoxyglucose-positron emission tomography (18F-FDG-PET) of the liver to evaluate possible changes in the tumor-to-background ratio considering an improved detection rate of liver lesions.


METHODS
Image acquisition for the first whole-body scan started at a mean time point of 69 min (55-110 min). The mean time interval between the injection of 18F-FDG and the second delayed scan was 100 min (85-166 min).


RESULTS
Of 90 proven liver metastases in 34 patients, the first scan detected 53 (59%) liver lesions correctly, whereas in the second, delayed scan 81 (90%) lesions were diagnosed correctly (p<0.001). The mean Standardized uptake values in the first and second delayed scan were 6.59 g/ml versus 8.09 g/ml, respectively (p<0.001). Tumor-to-background ratio of the first and second delayed scan were 2.0 and 2.7, respectively (p=0.04).


CONCLUSIONS
Dual-time-point-imaging of the liver showed a significant increase of tumor-to-background ratio and hypermetabolic lesion diameter. Although, 30% of all verified liver lesions could only be detected in the second delayed scan 10% of all malignant liver lesions were missed with FDG-PET.
Dirisamer
Albert
A
Radiology, University Hospital Vienna, Vienna, Austria. albert.dirisamer@meduniwien.ac.at
Halpern
Benjamin S
BS
Schima
Wolfgang
W
Heinisch
Martin
M
Wolf
Florian
F
Beheshti
Mohsen
M
Dirisamer
Franz
F
Weber
Michael
M
Langsteger
Werner
W
D000328:Adult; D000368:Aged; D001943:Breast Neoplasms; D015179:Colorectal Neoplasms; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary; D008297:Male; D008545:Melanoma / Q000000981:diagnostic imaging / Q000556:secondary; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods* / Q000706:statistics & numerical data; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D013997:Time Factors; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000706:statistics & numerical data
D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18