title: Detection and classification of focal liver lesions in patients with colorectal cancer: retrospective comparison of diffusion-weighted MR imaging and multi-slice CT.
abstract: OBJECTIVE
  To compare the diagnostic performance of diffusion-weighted MR imaging (DWI) with multi-slice CT (MS-CT) in the detection and classification of focal liver lesions in patients with colorectal cancer.
  
  
  METHODS
  In a retrospective study 68 patients who underwent DWI at 1.5 T (b-values of 50, 300 and 600s/mm(2)) and contrast-enhanced MS-CT were analysed by two radiologists blinded to the clinical results. Imaging results were correlated with intraoperative surgical and ultrasound findings (n=24), imaging follow-up or PET (n=44). Sensitivity of DWI and MS-CT in detection of focal liver lesions was compared on a per-lesion and a per-segment basis. Receiver operator-characteristic (ROC) curves to determine the diagnostic performance and the sensitivities of correctly identifying liver metastases on a segmental base were calculated.
  
  
  RESULTS
  For lesion detection, DWI was significantly superior to MS-CT both on a per-lesion (difference in sensitivities for reader 1 and 2 22.65% and 19.06%, p<0.0001) and a per-segment basis (16.86% and 11.76%, p<0.0001). Especially lesions smaller than 10mm were better detected with DWI compared to MS-CT (difference 41.10% and 29.45%, p<0.0001). ROC-analysis showed superiority for lesions classification (p<0.0001) of DWI (AUC: 0.949 and 0.951) as compared to MS-CT (AUC: 0.879 and 0.892, p<0.0001 and p=0.005). DWI was able to filter out metastatic segments with a higher sensitivity (88.2 and 86.5%) compared to MS-CT (68.0 and 67.4%, p<0.0001 and p=0.005, respectively).
  
  
  CONCLUSIONS
  Compared to MS-CT DWI is both more sensitive in the detection of liver lesions and more accurate in determining the extent of metastatic disease in patients with colorectal cancer and therefore might help to optimize therapeutic management in those patients.
authors.affiliation: Department of Radiology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany. matthias.eiber@tum.de
authors.forename: Matthias
authors.initials: M
authors.lastname: Eiber
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Fingerle
authors.forename: Melanie
authors.initials: M
authors.lastname: Brügel
authors.forename: Jochen
authors.initials: J
authors.lastname: Gaa
authors.forename: Ernst J
authors.initials: EJ
authors.lastname: Rummeny
authors.forename: Konstantin
authors.initials: K
authors.lastname: Holzapfel
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000175:diagnosis*; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*