title: Quantitative colorectal cancer perfusion measurement using dynamic contrast-enhanced multidetector-row computed tomography: effect of acquisition time and implications for protocols.
abstract: OBJECTIVE
  To determine the effect of acquisition time on quantitative colorectal cancer perfusion measurement.
  
  
  METHODS
  Dynamic contrast-enhanced computed tomography (CT) was performed prospectively in 10 patients with histologically proven colorectal cancer using 4-detector row CT (Lightspeed Plus; GE Healthcare Technologies, Waukesha, WI). Tumor blood flow, blood volume, mean transit time, and permeability were assessed for 3 acquisition times (45, 65, and 130 seconds). Mean values for all 4 perfusion parameters for each acquisition time were compared using the paired t test.
  
  
  RESULTS
  Significant differences in permeability values were noted between acquisitions of 45 seconds and 65 and 130 seconds, respectively (P=0.02, P=0.007). There was no significant difference for values of blood volume, blood flow, and mean transit time between any of the acquisition times.
  
  
  CONCLUSIONS
  Scan acquisitions of 45 seconds are too short for reliable permeability measurement in the abdomen. Longer acquisition times are required.
authors.affiliation: Intestinal Imaging Centre, St. Mark's Hospital, Harrow, United Kingdom.
authors.forename: Vicky
authors.initials: V
authors.lastname: Goh
authors.forename: Steve
authors.initials: S
authors.lastname: Halligan
authors.forename: Jo-Ann
authors.initials: JA
authors.lastname: Hugill
authors.forename: Louise
authors.initials: L
authors.lastname: Gartner
authors.forename: Clive I
authors.initials: CI
authors.lastname: Bartram
mesh_terms: D000230:Adenocarcinoma / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000378:metabolism; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001810:Blood Volume / Q000502:physiology; D003110:Colonic Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000378:metabolism; D003287:Contrast Media / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007479:Iopamidol / Q000493:pharmacokinetics; D008297:Male; D008875:Middle Aged; D010539:Permeability; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000378:metabolism; D012039:Regional Blood Flow / Q000502:physiology; D013997:Time Factors; D014018:Tissue Distribution; D036542:Tomography, Spiral Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007479:Iopamidol