title: Subtraction-multiphase-CT unbeneficial for early detection of colorectal liver metastases.
abstract: OBJECTIVE
  To assess the value of multiphase-subtraction-CT for early detection of colorectal-liver-metastases (CRLM).
  
  
  METHODS
  In 50 patients suspected of CRLM a routine pre-operative 4-phase-CT-scan of the upper abdomen was obtained. All 12 possible image subtractions between two different phases were constructed applying 3D-image-registration to decrease distortion artefacts induced by differences in inspiration volume. Two experienced radiologists initially reviewed the conventional 4-phase-CT for malignant and/or benign appearing lesions and at least 1-month hereafter the same 4-phase-CT now including the subtracted images. The results were compared to histology reports or to a combination of surgical exploration and intraoperative ultrasound together with results from pre-operative PET and follow-up examinations.
  
  
  RESULTS
  Although an additional number of 31 malignant appearing lesions were detected on the subtraction images, none proved to represent a true CRLM. Interobserver agreement (kappa) decreased from 0.627 (good) to 0.418 (fair).
  
  
  CONCLUSIONS
  Adding linearly co-registered subtraction-CT images to a conventional 4-phase-CT protocol does not improve detection of CRLM.
authors.affiliation: Department of Radiology, Vrije Universiteit Medisch Centrum, Amsterdam, The Netherlands. mr.meijerink@vumc.nl
authors.forename: Martijn R
authors.initials: MR
authors.lastname: Meijerink
authors.forename: Jan Hein T M
authors.initials: JH
authors.lastname: van Waesberghe
authors.forename: Richard P
authors.initials: RP
authors.lastname: Golding
authors.forename: Lineke
authors.initials: L
authors.lastname: van der Weide
authors.forename: Petrousjka
authors.initials: P
authors.lastname: van den Tol
authors.forename: Sybren
authors.initials: S
authors.lastname: Meijer
authors.forename: Cornelis
authors.initials: C
authors.lastname: van Kuijk
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015901:Angiography, Digital Subtraction / Q000379:methods; D002277:Carcinoma / Q000000981:diagnostic imaging* / Q000556:secondary*; D015179:Colorectal Neoplasms / Q000000981:diagnostic imaging*; D055088:Early Detection of Cancer / Q000379:methods*; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*