title: (18)F-FDG Uptake at the Surgical Margin after Hepatic Resection: Patterns of Uptake and Differential Diagnosis.
abstract: OBJECTIVE
  To evaluate the patterns of (18)F-FDG uptake at the surgical margin after hepatectomy to identify features that may differentiate benign and malignant uptake.
  
  
  METHODS
  Patients who had undergone a PET/CT after hepatectomy were identified. Delay between resection and PET/CT, presence of uptake at the surgical margin, pattern of uptake, and maximal standardized value were recorded. The PET/CT findings were correlated with contrast-enhanced CT or MRI.
  
  
  RESULTS
  There were 26 patients with increased 18F-FDG uptake; uptake was diffuse in seven and focal in 19. Diffuse uptake was due to inflammation in all cases. Focal uptake was due to recurrence in 12 and inflammation in seven cases. Defining a focal pattern only as a positive for malignancy yielded 100 % sensitivity, 87 % specificity, 37 % false positive rate. As expected, SUVmax was significantly higher for recurrence than inflammation, but did overlap. Contrast-enhanced CT allowed differentiation between malignant and benign uptake in all cases.
  
  
  CONCLUSIONS
  F-FDG uptake after hepatectomy does not equate to recurrence and yields a high false positive rate. Diffuse uptake did not require additional evaluation in our sample. Focal uptake, however, may be due to recurrence; differentiating benign and malignant nodular uptake relies on optimal contrast-enhanced CT or MRI.
  
  
  CONCLUSIONS
  • Marginal uptake exposes patients to the risk of false positive diagnosis of recurrence. • Benign and malignant patterns of marginal uptake overlap. • Diffuse marginal uptake in our experience, has a high chance to be inflammatory. • Focal marginal uptake can be due to recurrent tumour or inflammation. • Contrast-enhanced CT or MR allows the differentiation between benign and malignant uptake.
authors: Department of Radiology, University New Mexico, 2211 Lomas Boulevard, NE, Albuquerque, NM, 87106, USA.
authors: Silanath
authors: S
authors: Peungjesada
authors: Thomas A
authors: TA
authors: Aloia
authors: Patricia
authors: P
authors: Fox
authors: Beth
authors: B
authors: Chasen
authors: Sooyoung
authors: S
authors: Shin
authors: Ali
authors: A
authors: Baiomy
authors: Evelyne M
authors: EM
authors: Loyer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D006801:Humans; D008107:Liver Diseases / Q000175:diagnosis* / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods; D049268:Positron-Emission Tomography / Q000379:methods; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18