Value of water enema ¹⁸F-FDG PET/CT for diagnosis of rectal cancer

Objective: To investigate the diagnostic value of delayed water enema ¹⁸F-FDG PET/CT for rectal cancer. Methods: Sixty-nine cases (52 males, 17 females; average age 57.9 years) with clinically suspected rectal cancer underwent routine and delayed water enema ¹⁸F-FDG PET/CT. The imaging results were compared with colonoscopy and surgical pathology. The diagnostic efficiency of the two imaging methods was compared and so was the SUV_max of lesions. Paired t and McNemar test were used to analyze the data. Results: There were 61 rectal cancer cases confirmed by pathology. The SUV_max of rectal cancer calculated from routine and delayed water enema ¹⁸F-FDG PET/CT was significantly different (13.17 ± 6.19 vs 14.25 ± 6.63; t = -6.100, P < 0.01). The sensitivity, specificity and accuracy of routine ¹⁸F-FDG PET/CT and delayed water enema ¹⁸F-FDG PET/CT in diagnosis rectal cancer were 90.2% (55/61) vs 98.4% (60/61), 4/8 vs 6/8, 85.6% (59/69) vs 95.7% (66/69). A statistically significant difference was found in diagnostic accuracy between the two imaging methods (χ² = 5.140, P < 0.05). Conclusion: The delayed water enema ¹⁸F-FDG PET/CT has a complementary diagnostic value for routine ¹⁸F-FDG PET/CT in rectal cancer. (authors)