Incidental anal 18fluorodeoxyglucose uptake: Should we further examine the patient?

Figure 1 Flow chart. Among the 144 patients with non-incidental uptake, 121 had known anal cancer; 14 had pelvic cancer with known anal extension; 2 had a known abnormality on anorectal examination at the time of the positron emission tomography with computed tomography; 7 had recent pelvic radiotherapy or surgery. PET/CT: Positron emission tomography with computed tomography.

Figure 2 Incidental anal ¹⁸F-fluorodeoxyglucose uptake. A: An incidental anal ¹⁸F-fluorodeoxyglucose uptake in 1 study patient with hemo rrhoidal disease that required medical treatment (standardized uptake value max = 18.1); B: An incidental anal ¹⁸F-fluorodeoxyglucose uptake in 1 study patient without proctological diagnosis (standardized uptake value max = 4.9); C: An incidental anal ¹⁸F-fluorodeoxyglucose uptake in 1 study patient with hemorrhoidal disease that did not require treatment (standardized uptake value max = 8.8).

Figure 3 Receiver operating characteristic curve. A: Standardized uptake value mean; B: Standardized uptake value max; C: Metabolic volumes 41; D: Metabolic volumes 30, to differentiate patients requiring treatment from others. AUC: Area under the curve.