title: Diagnostic imaging of colorectal liver metastases with CT, MR imaging, FDG PET, and/or FDG PET/CT: a meta-analysis of prospective studies including patients who have not previously undergone treatment.
abstract: OBJECTIVE
  To obtain diagnostic performance values of computed tomography (CT), magnetic resonance (MR) imaging, fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET), and FDG PET/CT in the detection of colorectal liver metastases in patients who have not previously undergone therapy.
  
  
  METHODS
  A comprehensive search was performed for articles published from January 1990 to January 2010 that fulfilled the following criteria: a prospective study design was used; the study population included at least 10 patients; patients had histopathologically proved colorectal cancer; CT, MR imaging, FDG PET, or FDG PET/CT was performed for the detection of liver metastases; intraoperative findings or those from histopathologic examination or follow-up were used as the reference standard; and data for calculating sensitivity and specificity were included. Study design characteristics, patient characteristics, imaging features, reference tests, and 2 × 2 tables were recorded.
  
  
  RESULTS
  Thirty-nine articles (3391 patients) were included. Variation existed in study design characteristics, patient descriptions, imaging features, and reference tests. The sensitivity estimates of CT, MR imaging, and FDG PET on a per-lesion basis were 74.4%, 80.3%, and 81.4%, respectively. On a per-patient basis, the sensitivities of CT, MR imaging, and FDG PET were 83.6%, 88.2%, and 94.1%, respectively. The per-patient sensitivity of CT was lower than that of FDG PET (P = .025). Specificity estimates were comparable. For lesions smaller than 10 mm, the sensitivity estimates for MR imaging were higher than those for CT. No differences were seen for lesions measuring at least 10 mm. The sensitivity of MR imaging increased significantly after January 2004. The use of liver-specific contrast material and multisection CT scanners did not provide improved results. Data about FDG PET/CT were too limited for comparisons with other modalities.
  
  
  CONCLUSIONS
  MR imaging is the preferred first-line modality for evaluating colorectal liver metastases in patients who have not previously undergone therapy. FDG PET can be used as the second-line modality. The role of FDG PET/CT is not yet clear owing to the small number of studies.
  
  
  BACKGROUND
  http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.10100729/-/DC1.
authors.affiliation: Department of Radiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands. mniekel@gmail.com
authors.forename: Maarten Christian
authors.initials: MC
authors.lastname: Niekel
authors.forename: Shandra
authors.initials: S
authors.lastname: Bipat
authors.forename: Jaap
authors.initials: J
authors.lastname: Stoker
mesh_terms: D015179:Colorectal Neoplasms / Q000473:pathology*; D003287:Contrast Media; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary*; D008279:Magnetic Resonance Imaging; D049268:Positron-Emission Tomography; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18