Feasibility of detecting small intestinal disease by FDG-PET/CT

Positron emission tomography (PET)/computed tomography with ¹⁸F-fluorodeoxyglucose (FDG) is widely used for the diagnosis of malignant tumors. However, we occasionally encounter cases in which pathological accumulation is indistinguishable from physiological accumulation. We conducted a retrospective study of the maximum standardized uptake value (SUVmax) and the distribution pattern of FDG accumulation in 80 evaluable patients with records of accumulation in the small intestine identified from data acquired at Dokkyo Medical University PET Center from March 2005 to December 2010. Our aim was to distinguish pathological accumulation from physiological accumulation. Nineteen of the 80 patients had lesions that required some form of treatment. These lesions were categorized as pathological accumulation, while other 65 lesions in 61 patients were categorized as physiological accumulation. Cases with diffuse accumulation in the intestinal tract were assigned to Group L (linear), all others to Group F (focal), in our analysis. Lesions were focal in 22 patients and linear in 62. The pathological accumulation group had a mean SUVmax of 12.2, which was higher than that of 5.0 in the physiological accumulation group, and included more lesions that were categorized into Group F (16 of 19 lesions). The sensitivity and specificity for detecting focal accumulation regarded as being pathological accumulation were 84% and 91%, respectively, and accuracy was 89%. The sensitivity and specificity with a cut-off SUVmax of 5.87 obtained in the ROC analysis were 84% and 78%, respectively, and accuracy was 80%. Evaluation of SUVmax in the small intestine and the distribution pattern of FDG accumulation may be useful for diagnosing lesions in the small intestine.