title: FDG-PET/CT assessment of misty mesentery: feasibility for distinguishing viable mesenteric malignancy from stable conditions.
abstract: OBJECTIVE
  "Misty mesentery" is a CT appearance of mesenteric fat changes with increased attenuation often existing with swelled mesenteric lymph nodes. We evaluated diagnostic performance of FDG-PET/CT in distinguishing viable malignant disorders from benign conditions in misty mesentery.
  
  
  METHODS
  4236 FDG-PET/CT images were reviewed to identify patients with appearances of misty mesentery. Only the initial examinations were evaluated. Patients undergoing chemotherapy and/or radiotherapy within 3 months, patients with bulky mesenteric mass, and patients without follow-up examinations were excluded. Maximum short-axis diameter of mesenteric nodules (Diam-max) and maximum standardized uptake value (SUVmax) for mesenteric abnormalities were measured, and the diagnostic performance to differentiate between viable malignancy and stable lesions was assessed by receiver-operating characteristic (ROC) analysis, based on final diagnoses obtained by histology or follow-up examinations. Their significance was assessed by multivariate logistic regression.
  
  
  RESULTS
  71 studies met the inclusion criteria with confirmed diagnoses (13 viable malignancies; 58 stable lesions). Of the 13 malignant cases, 12 were lymphoma. ROC curves indicated an optimal Diam-max cut-off value of >10mm and SUVmax cut-off of ≥3.0, with area under the curve of 0.961 and 0.926, respectively. Using the optimal Diam-max cut-off, sensitivity and specificity were 69% and 98%, respectively. Using the optimal SUVmax cut-off, they were 85% and 98%, respectively. The combination of either Diam-max>10mm or SUVmax≥3.0 had a sensitivity of 92%. Both Diam-max and SUVmax were significant independent factors for predicting malignancy.
  
  
  CONCLUSIONS
  FDG-PET/CT is feasible for identifying viable malignancy in misty mesentery.
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto University Hospital, 54 Shogoin-kawahara-cho, Sakyo-Ku, Kyoto, Japan. koyakn@kuhp.kyoto-u.ac.jp
authors.forename: Koya
authors.initials: K
authors.lastname: Nakatani
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nakamoto
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005240:Feasibility Studies; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008643:Mesentery / Q000000981:diagnostic imaging* / Q000473:pathology*; D008875:Middle Aged; D064847:Multimodal Imaging; D010534:Peritoneal Neoplasms / Q000175:diagnosis* / Q000453:epidemiology*; D049268:Positron-Emission Tomography / Q000706:statistics & numerical data*; D015995:Prevalence; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18