title: Perfusion CT to assess angiogenesis in colon cancer: technical limitations and practical challenges.
abstract: OBJECTIVE
  Perfusion CT may have the potential to quantify the degree of angiogenesis of solid tumours in vivo. This study aims to identify the practical and technical challenges inherent to the technique, and evaluate its feasibility in colorectal tumours.
  
  
  METHODS
  51 patients from 2 institutions prospectively underwent a single perfusion CT on 2 different multidetector scanners. The patients were advised to breath-hold as long as possible, followed by shallow breathing, and were given intravenous buscopan to reduce movement. Numerous steps were explored to identify the challenges.
  
  
  RESULTS
  43 patients successfully completed the perfusion CT as per protocol. Inability to detect the tumour (n=3), misplacement of dynamic sequence co-ordinates (n=2), failure of contrast injection (n=2) and displacement of tumour (n=1) were the reasons for failure. In 14 cases excessive respiratory motion displaced the tumour out of the scanning field along the temporal sequence, leading to erroneous data capture. In nine patients, minor displacements of the tumour were corrected by repositioning the region of interest (ROI) to its original position after reviewing each dynamic sequence slice. In 20 patients the tumour was stable, and data captured from the ROI were representative, and could have been analysed by commercially available Body Tumor Perfusion 3.0® software (GE Healthcare, Waukesha, WI). Hence all data were manually analysed by MATLAB® processing software (MathWorks, Cambridge, UK).
  
  
  CONCLUSIONS
  Perfusion CT in tumours susceptible to motion during acquisition makes accurate data capture challenging and requires meticulous attention to detail. Motion correction software is essential if perfusion CT is to be used routinely in colorectal cancer.
authors.affiliation: Department of Surgery, Mayday University Hospital, Croydon, UK.
authors.forename: S
authors.initials: S
authors.lastname: Dighe
authors.forename: E
authors.initials: E
authors.lastname: Castellano
authors.forename: H
authors.initials: H
authors.lastname: Blake
authors.forename: N
authors.initials: N
authors.lastname: Jeyadevan
authors.forename: M U
authors.initials: MU
authors.lastname: Koh
authors.forename: M
authors.initials: M
authors.lastname: Orten
authors.forename: I
authors.initials: I
authors.lastname: Swift
authors.forename: G
authors.initials: G
authors.lastname: Brown
mesh_terms: D003110:Colonic Neoplasms / Q000098:blood supply* / Q000000981:diagnostic imaging; D003287:Contrast Media; D005240:Feasibility Studies; D006801:Humans; D007083:Iliac Artery / Q000000981:diagnostic imaging; D007472:Iohexol; D009068:Movement; D009389:Neovascularization, Pathologic / Q000000981:diagnostic imaging*; D055420:Perfusion Imaging / Q000379:methods*; D011446:Prospective Studies; D012984:Software; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D003287:Contrast Media; D007472:Iohexol