title: Positron emission tomography/computed tomographic scans compared to computed tomographic scans for detecting colorectal liver metastases: a systematic review.
abstract: OBJECTIVE
  To review diagnostic accuracy of positron emission tomography/computed tomography (PET/CT) for colorectal liver metastases.
  
  
  BACKGROUND
  Colorectal liver metastases can be treated with surgical resection; however, recurrence is seen in 58% of patients. PET/CT may better detect extra-hepatic disease before surgery to more accurately identify eligible candidates for surgery and, through better selection, improve patient prognosis.
  
  
  METHODS
  We conducted a comprehensive systematic review on adults with colorectal liver metastases who received PET/CT and CT scans to detect metastases. The gold standard to confirm the diagnosis was histology. Study selection, quality assessment, and data extraction were completed independently by 2 investigators. Pooling of results was not feasible because of heterogeneity. A qualitative summary of results is presented.
  
  
  RESULTS
  From 1083 citations, we identified 6 studies (440 patients) for the review. For extra-hepatic lesions (3 studies; 178 patients), PET/CT was more sensitive than CT, but specificities were similar (PET/CT sensitivity [SN] = 75%-89% and specificity [SP] = 95%-96% vs. CT SN = 58%-64% and SP = 87%-97%). For hepatic lesions (5 studies; 316 patients), PET/CT had higher SN and SP than CT (PET/CT SN = 91%-100% and SP = 75%-100%; CT SN = 78%-94% and SP = 25%-98%). For local recurrence (3 studies; 206 patients), PET/CT also had better accuracy than CT with SN = 93% to 100% and SP = 97% to 98% versus SN = 0 %-100% and SP = 97%-98%.
  
  
  CONCLUSIONS
  Based on this systematic review, we conclude that PET/CT has a higher accuracy for detection of extra-hepatic and hepatic colorectal metastatic disease than CT alone. However, the results are based on a small number of studies and should be interpreted cautiously.
authors.affiliation: Department of Public Health, University of Alberta, Edmonton, Canada. seema@ualberta.ca
authors.forename: Seema
authors.initials: S
authors.lastname: Patel
authors.forename: Michael
authors.initials: M
authors.lastname: McCall
authors.forename: Arto
authors.initials: A
authors.lastname: Ohinmaa
authors.forename: David
authors.initials: D
authors.lastname: Bigam
authors.forename: Donna M
authors.initials: DM
authors.lastname: Dryden
mesh_terms: D000328:Adult; D000368:Aged; D017024:Chemotherapy, Adjuvant; D015179:Colorectal Neoplasms / Q000473:pathology* / Q000628:therapy; D005260:Female; D006498:Hepatectomy / Q000379:methods; D006801:Humans; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000556:secondary* / Q000601:surgery / Q000628:therapy; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D018714:Radiotherapy, Adjuvant; D014057:Tomography, X-Ray Computed / Q000379:methods*