title: Quantitative assessment of tissue perfusion using MDCT: comparison of colorectal cancer and skeletal muscle measurement reproducibility.
abstract: OBJECTIVE
  The purposes of this study were to determine the reproducibility of quantitative colorectal cancer perfusion measurements using dynamic contrast-enhanced MDCT, and to compare this with measurements from skeletal muscle.
  
  
  METHODS
  Ten patients (mean age, 67 years; six men, four women) with histologically proven colorectal cancer were examined prospectively using 4-MDCT. Perfusion studies (cine mode; 4 x 5 mm collimation; 1 acquisition/s; 65 seconds total) were performed through the tumor epicenter after IV bolus contrast administration (iopamidol 340, 100 mL; 5 mL/s) and repeated within 48 hours. Quantitative values for blood volume, blood flow, mean transit time, and permeability were determined using commercial software. Two regions of interest were studied on the axial image: one within the tumor and another within the left gluteal muscle. Measurement reproducibility was assessed using Bland-Altman statistics.
  
  
  RESULTS
  For the tumor, the mean difference (95% limits of agreement) was -0.04 mL/100 g tissue (-2.50, 2.42); 8.80 (-50.5, 68.0) mL/100 g tissue/min; -0.99 (-8.19, 6.20) seconds; and 1.20 (-5.42, 7.83) mL/100 g tissue/min for blood volume, blood flow, mean transit time, and permeability, respectively. For muscle, the mean difference (95% limits of agreement) was 0.02 (-1.40, 1.43), 6.60 (-11.2, 24.3), -3.76 (-16.87, 9.35), and 1.30 (-4.68, 7.28), respectively.
  
  
  CONCLUSIONS
  Quantitative perfusion measurements are reproducible. Measurements from tumor are less variable than from skeletal muscle.
authors.affiliation: Paul Strickland Scanner Centre, Mt. Vernon Hospital, Northwood, 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: Clive I
authors.initials: CI
authors.lastname: Bartram
mesh_terms: D000230:Adenocarcinoma / Q000098:blood supply* / Q000000981:diagnostic imaging; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity; D001810:Blood Volume; D002081:Buttocks; D002199:Capillary Permeability; D015179:Colorectal Neoplasms / Q000098:blood supply* / Q000000981:diagnostic imaging; D003287:Contrast Media; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007479:Iopamidol; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000000981:diagnostic imaging; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed
chemical_list: D003287:Contrast Media; D007479:Iopamidol