Positron tomography with 18F-fluorodeoxyglucose in the preoperative evaluation of gallbladder lesions suspicious of malignancy: Diagnostic utility and clinical impact

Background

Gallbladder carcinoma is a neoplasm having a poor prognosis in which the role of positron emission tomography with ¹⁸F-fluordeoxyglucose as a diagnostic tool, although of possible usefulness, has not been well-defined.

Methods/design

It is a prospective cohort of patients with radiologically malignant suspicious gallbladder lesions. A staging diagnostic presurgical FDG-PET study was carried out in each patient using both dedicated PET and multimodality PET-CT scanners. Diagnostic accuracy parameters were calculated from the results of PET imaging and were correlated with the condition and/or the clinical course of the patients. The clinical impact of its implementation in the diagnosis of gallbladder carcinoma was also analyzed.

Results

A total of 42 patients were recruited (22 malignant lesions, 20 benign). Overall diagnostic accuracy was 83.33% for the diagnosis of the primary lesion, 88.89% for the evaluation of lymph node involvement and 85.1% for the evaluation of metastatic disease. Mean SUVmax in malignant gallbladder lesions was 6.14 ± 2.89. ROC curve showed a cut-off value of 3.65 in the SUVmax for malignancy. Accuracy of PET studies alone (n = 21) was slightly lower than that of the PET/CT (n = 21). FDG-PET changed the management of 14.8% of the population due to the identification of unsuspected metastatic disease.

Comments

FDG-PET accurately diagnoses malignancy or benignity of suspicious gallbladder lesions, with the addition of its capacity to identify unsuspected metastatic disease. PET-CT improves the diagnostic accuracy of the procedure, due to the metabolic-structural complementarity of their information. The SUVmax has a complementary value added to the visual analysis.