The possible role of F-18 FDG positron emission tomography in the differential diagnosis of focal pancreatic lesions.
OBJECTIVE
To compare the diagnostic values of different methods for the differentiation of malignant from benign pancreatic lesions.


METHODS
In 22 patients with focal pancreatic lesions, the carbohydrate antigen (CA) 19-9 level was measured; abdominal ultrasound (US), computed tomography (CT), endoscopic retrograde cholangiopancreatography (ERCP), and F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) were performed; and the value of these methods were analyzed for their use in cancer diagnosis.


RESULTS
Malignant lesions were identified in six patients and verified by surgery or clinical follow-up. The CA 19-9 level was elevated in four of the five patients examined (sensitivity, 80%). In all six cases, US and CT revealed hypoechogenic and hypodense areas (sensitivity, 100%). In one patient, ERCP was unsuccessful but yielded true-positive results in three others (sensitivity, 60%). The sensitivity of FDG PET was 100%. Sixteen focal cases of pancreatic disease proved to be benign. The CA 19-9 level was elevated in four of them (specificity, 73%). Hypoechogenic and hypodense areas were evident on US and CT in eight patients. The specificity of CT was 50% (8 of 16 cases). The specificity of US was 47% (7 of 15 cases). The specificity of successful ERCP was 92%. Fourteen negative FDG-PET results were truly negative. In two patients, however, the PET findings proved to be falsely positive (specificity, 88%).


CONCLUSIONS
FDG-PET is an effective tool to differentiate malignant from benign focal pancreatic lesions. In persons with focal pancreatic hypoechogenic or hypodense lesions detected by CT or US and an elevated CA 19-9 level, FDG PET should be the next step in the diagnostic strategy.
Papós
Miklós
M
Department of Nuclear Medicine, First Department of Medicine, University of Szeged, Szeged, Hungary. paposm@comser.szote.u-szeged.hu
Takács
Tamás
T
Trón
Lajos
L
Farkas
Gyula
G
Ambrus
Edit
E
Szakáll
Szabolcs
S
Lonovics
János
J
Csernay
László
L
Pávics
László
L
D000328:Adult; D018395:CA-19-9 Antigen / Q000032:analysis; D002760:Cholangiopancreatography, Endoscopic Retrograde; D003937:Diagnosis, Differential; D005260:Female; D005462:Fluorine Radioisotopes; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D010182:Pancreatic Diseases / Q000000981:diagnostic imaging*; D010190:Pancreatic Neoplasms / Q000000981:diagnostic imaging* / Q000276:immunology / Q000601:surgery; D019275:Radiopharmaceuticals; D014055:Tomography, Emission-Computed; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
D018395:CA-19-9 Antigen; D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18