18F-choline PET/CT physiological distribution and pitfalls  in image interpretation: experience in 80 patients with  prostate cancer.
OBJECTIVE
18F-choline positron emission tomography (PET)/computed tomography (CT) is an integral part in restaging of patients with prostate cancer (PC). The aim of this study was to describe the whole-body physiologic distribution of 18F-choline and to discuss some abnormal sites of uptake not related to PC we observed.


METHODS
Eighty consecutive patients submitted to 18F-choline PET/CT imaging for primary staging or biochemical recurrence (prostate specific antigen rising) after treatment of PC was considered. Whole-body PET/CT was acquired approximately 40 min after 18F-choline injection.


RESULTS
We observed physiological 18F-choline uptake in liver, pancreas, spleen, salivary and lachrymal glands and also, owing to renal excretion, in urinary tract. Other sites of less intense tracer uptake were bone marrow and intestines. We found abnormal and unexpected PET findings in 15 patients (18.7%), not owing to PC localizations. The majority of these findings were owing to inflammation (12 of 15); a case of low grade lymphoma was detected; two patients showed focal brain uptake of 18F-choline and were subsequently submitted to magnetic resonance: in one a meningioma and in the other a low-grade brain tumour were diagnosed.


CONCLUSIONS
Accurate knowledge of the biodistribution of 18F-choline is essential for the correct interpretation of PET/CT imaging. CT enables differentiation of physiological bowel activity and 18F-choline excretion in the ureters. In our series, 18F-choline uptake in benign pathological conditions mainly included sites of inflammation; nevertheless, accumulation in tumour deposits not because PC cannot be excluded, particularly in the brain, where correlative imaging with magnetic resonance is of the utmost importance.
Schillaci
Orazio
O
Department of Diagnostic Imaging, Molecular Imaging, Interventional Radiology and Radiotherapy, University Hospital Tor Vergata, Rome, Italy.
Calabria
Ferdinando
F
Tavolozza
Mario
M
Cicciò
Carmelo
C
Carlani
Marco
M
Caracciolo
Cristiana R
CR
Danieli
Roberta
R
Orlacchio
Antonio
A
Simonetti
Giovanni
G
D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism; D002794:Choline / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007249:Inflammation / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011471:Prostatic Neoplasms / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism*; D003074:Solitary Pulmonary Nodule / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism; D014018:Tissue Distribution; D014057:Tomography, X-Ray Computed; D051598:Whole Body Imaging
C516370:fluoromethylcholine; D002794:Choline