title: Comparison between perfusion computed tomography and dynamic contrast-enhanced magnetic resonance imaging in rectal cancer.
abstract: OBJECTIVE
  To compare pretreatment scans with perfusion computed tomography (pCT) vs. dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in rectal tumors.
  
  
  METHODS
  Nineteen patients diagnosed with rectal cancer were included in this prospective study. All patients underwent both pCT and DCE-MRI. Imaging was performed on a dedicated 40-slice CT-positron emission tomography system and a 3-T MRI system. Dynamic contrast enhancement was measured in tumor tissue and the external iliac artery. Tumor perfusion was quantified in terms of pharmacokinetic parameters: transfer constant K(trans), fractional extravascular-extracellular space v(e), and fractional plasma volume v(p). Pharmacokinetic parameter values and their heterogeneity (by 80% quantile value) were compared between pCT and DCE-MRI.
  
  
  RESULTS
  Tumor K(trans) values correlated significantly for the voxel-by-voxel-derived median (Kendall's tau correlation, tau = 0.81, p < 0.001) and 80% quantile (tau = 0.54, p = 0.04), as well as for the averaged uptake (tau = 0.58, p = 0.03). However, no significant correlations were found for v(e) and v(p) derived from the voxel-by-voxel-derived median and 80% quantile and derived from the averaged uptake curves.
  
  
  CONCLUSIONS
  This study demonstrated for the first time that pCT provides K(trans) values comparable to those of DCE-MRI. However, no correlation was found for the v(e) and v(p) parameters between CT and MRI. Computed tomography can serve as an alternative modality to MRI for the in vivo evaluation of tumor angiogenesis in terms of the transfer constant K(trans).
authors.affiliation: Department of Radiation Oncology, Maastricht University Medical Center, GROW School for Oncology and Developmental Biology, Maastricht, The Netherlands.
authors.forename: Roel G J
authors.initials: RG
authors.lastname: Kierkels
authors.forename: Walter H
authors.initials: WH
authors.lastname: Backes
authors.forename: Marco H M
authors.initials: MH
authors.lastname: Janssen
authors.forename: Jeroen
authors.initials: J
authors.lastname: Buijsen
authors.forename: Regina G H
authors.initials: RG
authors.lastname: Beets-Tan
authors.forename: Philippe
authors.initials: P
authors.lastname: Lambin
authors.forename: Guido
authors.initials: G
authors.lastname: Lammering
authors.forename: Michel C
authors.initials: MC
authors.lastname: Oellers
authors.forename: Hugo J W L
authors.initials: HJ
authors.lastname: Aerts
mesh_terms: D000368:Aged; D003287:Contrast Media / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D008954:Models, Biological; D049268:Positron-Emission Tomography / Q000379:methods*; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media