title: Whole-liver CT texture analysis in colorectal cancer: Does the presence of liver metastases affect the texture of the remaining liver?
abstract: BACKGROUND
  Liver metastases limit survival in colorectal cancer. Earlier detection of (occult) metastatic disease may benefit treatment and survival.
  
  
  OBJECTIVE
  The objective of this article is to evaluate the potential of whole-liver CT texture analysis of apparently disease-free liver parenchyma for discriminating between colorectal cancer (CRC) patients with and without hepatic metastases.
  
  
  METHODS
  The primary staging CT examinations of 29 CRC patients were retrospectively analysed. Patients were divided into three groups: patients without liver metastases (n = 15), with synchronous liver metastases (n = 10) and metachronous liver metastases within 18 months following primary staging (n = 4). Whole-liver texture analysis was performed by delineation of the apparently non-diseased liver parenchyma (excluding metastases or other focal liver lesions) on portal phase images. Mean grey-level intensity (M), entropy (E) and uniformity (U) were derived with no filtration and different filter widths (0.5 = fine, 1.5 = medium, 2.5 = coarse).
  
  
  RESULTS
  Mean E1.5 and E2.5 for the whole liver in patients with synchronous metastases were significantly higher compared with the non-metastatic patients (p = 0.02 and p = 0.01). Mean U1.5 and U2.5 were significantly lower in the synchronous metastases group compared with the non-metastatic group (p = 0.04 and p = 0.02). Texture parameters for the metachronous metastases group were not significantly different from the non-metastatic group or synchronous metastases group (p > 0.05), although - similar to the synchronous metastases group - there was a subtle trend towards increased E1.5, E2.5 and decreased U1.5, U2.5 values. Areas under the ROC curve for the diagnosis of synchronous metastatic disease based on the texture parameters E1.5,2.5 and U1.5,2.5 ranged between 0.73 and 0.78.
  
  
  CONCLUSIONS
  Texture analysis of the apparently non-diseased liver holds promise to differentiate between CRC patients with and without metastatic liver disease. Further research is required to determine whether these findings may be used to benefit the prediction of metachronous liver disease.
authors.affiliation: Department of Radiology, Maastricht University Medical Center, The Netherlands ; Department of Radiology, Zhongshan Hospital, Fudan University, China.
authors.forename: Sheng-Xiang
authors.initials: SX
authors.lastname: Rao
authors.affiliation: Department of Radiology, Maastricht University Medical Center, The Netherlands.
authors.forename: Doenja Mj
authors.initials: DM
authors.lastname: Lambregts
authors.affiliation: Department of Radiology, Maastricht University Medical Center, The Netherlands.
authors.forename: Roald S
authors.initials: RS
authors.lastname: Schnerr
authors.affiliation: Department of Radiology, Maastricht University Medical Center, The Netherlands ; Department of Radiology, Catharina Hospital Eindhoven, The Netherlands.
authors.forename: Wenzel
authors.initials: W
authors.lastname: van Ommen
authors.affiliation: Department of Radiology, Maastricht University Medical Center, The Netherlands.
authors.forename: Thiemo Ja
authors.initials: TJ
authors.lastname: van Nijnatten
authors.affiliation: Department of Radiology, Maastricht University Medical Center, The Netherlands ; Department of Surgery, Maastricht University Medical Center, The Netherlands.
authors.forename: Milou H
authors.initials: MH
authors.lastname: Martens
authors.affiliation: Department of Radiology, Maastricht University Medical Center, The Netherlands ; Department of Surgery, Maastricht University Medical Center, The Netherlands.
authors.forename: Luc A
authors.initials: LA
authors.lastname: Heijnen
authors.affiliation: Department of Radiology, Maastricht University Medical Center, The Netherlands.
authors.forename: Walter H
authors.initials: WH
authors.lastname: Backes
authors.affiliation: Department of Surgical Oncology, Erasmus MC Cancer Institute, The Netherlands.
authors.forename: Cornelis
authors.initials: C
authors.lastname: Verhoef
authors.affiliation: Department of Radiology, Zhongshan Hospital, Fudan University, China.
authors.forename: Meng-Su
authors.initials: MS
authors.lastname: Zeng
authors.affiliation: Department of Surgery, Maastricht University Medical Center, The Netherlands ; GROW School for Oncology and Developmental Biology, The Netherlands.
authors.forename: Geerard L
authors.initials: GL
authors.lastname: Beets
authors.affiliation: Department of Radiology, Maastricht University Medical Center, The Netherlands ; GROW School for Oncology and Developmental Biology, The Netherlands.
authors.forename: Regina Gh
authors.initials: RG
authors.lastname: Beets-Tan
keywords: CT texture; Colorectal cancer; liver metastases; metachronous metastases; occult disease