Relationship between FDG uptake and the pathological risk category in gastrointestinal stromal tumors.
OBJECTIVE
To evaluate (18)F-fluorodeoxyglucose (FDG) uptake and the pathological risk category of gastrointestinal stromal tumors (GISTs), and to investigate the possibility of determining the pathological risk category by positron emission tomography/computed tomography (PET/CT).


METHODS
We undertook 29 PET/CT studies in 20 patients with GISTs. Eleven of the 20 patients underwent PET/CT prior to therapy, with three of these also undergoing follow-up PET/CT after operation or imatinib therapy.


RESULTS
All eleven lesions imaged before treatment were FDG-positive on PET/CT. Seven of these eleven primary lesions were categorized as high risk and the other four primary lesions were categorized as low or intermediate risk. There was a significant difference between the maximum standardized uptake value (SUVmax) of the primary lesions categorized as high risk (11.8±3.15) and that of the primary lesions categorized as low and intermediate risk (2.88±0.47) (p<0.001). Recurrent tumors were also shown as FDG-positive.


CONCLUSIONS
Primary GISTs and recurrent tumors can be detected by PET/CT. Our study suggests that the degree of FDG uptake is a useful indicator of risk category. In addition, PET/CT is probably useful for follow-up examinations of GIST after operation or imatinib therapy. J. Med. Invest. 57: 270-274, August, 2010.
Otomi
Yoichi
Y
Department of Radiology, Institute of Health Biosciences, the University of Tokushima Graduate School, Kuramoto-cho, Tokushima, Japan.
Otsuka
Hideki
H
Morita
Naomi
N
Terazawa
Kaori
K
Furutani
Kaori
K
Harada
Masafumi
M
Nishitani
Hiromu
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000970:Antineoplastic Agents / Q000627:therapeutic use; D001549:Benzamides; D005260:Female; D019788:Fluorodeoxyglucose F18; D046152:Gastrointestinal Stromal Tumors / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000628:therapy; D006801:Humans; D000068877:Imatinib Mesylate; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D010879:Piperazines / Q000627:therapeutic use; D049268:Positron-Emission Tomography; D011743:Pyrimidines / Q000627:therapeutic use; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012307:Risk Factors; D014057:Tomography, X-Ray Computed
D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D000068877:Imatinib Mesylate