title: Comparative accuracy of intravenous contrast-enhanced CT versus noncontrast CT plus intravenous contrast-enhanced CT in the detection and characterization of patients with hypervascular liver metastases: a critically appraised topic.
abstract: OBJECTIVE
  To evaluate whether addition of nonenhanced computed tomography (NECT) to intravenous contrast-enhanced (CE) abdominal CT improves detection or characterization of hypervascular liver masses. Patients were referred for initial staging or follow-up with known breast, melanoma, neuroendocrine, or thyroid cancer.
  
  
  METHODS
  The literature was searched using the patient, intervention, comparison, and outcome (PICO) method. Retrieved articles were critically appraised and assigned a level of evidence based on the Oxford University Centre for Evidence-based Medicine hierarchy of validity for diagnostic studies.
  
  
  RESULTS
  One thousand one hundred studies were reviewed; only 11 studies matched the PICO of our study and were appraised. Most of the appraised articles were published in the 1990s using older technology and contrast delivery. The retrieved diagnostic performance for characterization of liver metastases showed sensitivity/specificity of 97%/76% for NECT, 97%/75% for arterial CT, and 98%/76% for portal venous phase CT in patients with breast cancer; sensitivity of 96% (arterial and portal CT) versus 100% (NECT, arterial and portal CT) in patients with melanoma; and sensitivity of 43% (portal CT) versus 17% (NECT) in patients with neuroendocrine tumor. No primary study was found for performance of different CT protocols in patients with thyroid cancer. Available evidence showed radiologists reported more conspicuous liver masses on CECT compared to NECT in patients with breast or neuroendocrine cancer.
  
  
  CONCLUSIONS
  Based on existing evidence, NECT only adds a small incremental value to CECT for detection/characterization of hypervascular liver metastases. Addition of NECT increases patient's exposure to radiation and the number of images available for interpretation.
authors: Department of Radiology, Emory University School of Medicine, 1364 Clifton Rd NE, Atlanta, GA 30322. Electronic address: gsadigh@emory.edu.
authors: Gelareh
authors: G
authors: Sadigh
authors: Department of Radiology, Children's Hospital of Atlanta and Emory University School of Medicine, Atlanta, Georgia.
authors: Kimberly E
authors: KE
authors: Applegate
authors: Division of Abdominal Imaging, Department of Radiology, Emory University School of Medicine, Atlanta, Georgia.
authors: Deborah A
authors: DA
authors: Baumgarten
mesh_terms: D003287:Contrast Media / Q000008:administration & dosage*; D006801:Humans; D007275:Injections, Intravenous; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary*; D009389:Neovascularization, Pathologic / Q000000981:diagnostic imaging*; D011856:Radiographic Image Enhancement / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods* / Q000706:statistics & numerical data
chemical_list: D003287:Contrast Media
keywords: Computed tomography; contrast media; critically appraised topic; early detection of cancer; liver; neoplasm metastasis