Quantitative assessment of colorectal cancer perfusion using MDCT: inter- and intraobserver agreement.
OBJECTIVE
The objective of our study was to determine inter- and intraobserver agreement of MDCT colorectal cancer perfusion measurements.


METHODS
Thirty-one patients (17 men, 14 women; median age, 69 years) with proven colorectal cancer were examined prospectively using MDCT. A 65-sec dynamic study (cine mode, 4 x 5 mm collimation) was acquired through the tumor after i.v. contrast administration (100 mL of iopamidol 350, 5 mL/sec). Tumor blood volume, blood flow, mean transit time, and permeability measurements were determined by two independent observers using commercial software. Inter- and intraobserver agreement was assessed using the Bland-Altman test.


RESULTS
The mean difference for interobserver agreement (95% limits of agreement) was -0.81 mL/100 g tissue (-3.14 to 1.52); -9.94 mL/100 g tissue/min (-51.43 to 32.65); -1.09 sec (-7.05 to 4.86); and -2.90 mL/100 g tissue/min (-11.48 to 5.68) for blood volume, blood flow, mean transit time, and permeability, respectively. The intraclass correlation coefficient was 0.83, 0.89, 0.89, and 0.80, respectively. The mean difference for intraobserver agreement (95% limits of agreement) was 0.12 mL/100 g tissue (-1.90 to 2.14); 0.02 mL/100 g tissue/min (-13.13 to 13.17); -0.19 sec (-3.19 to 2.81); and 0.00 mL/100 g tissue/min (-2.45 to 2.45) for observer 1 and 0.26 mL/100 g tissue (-1.46 to 1.98); 4.47 mL/100 g tissue/min (-26.65 to 35.59); -0.21 sec (-2.48 to 2.06); 1.08 mL/100 g tissue/min (-4.92 to 7.08) for observer 2. The intraclass correlation coefficient was 0.86, 0.98, 0.97, 0.98 for observer 1 and 0.93, 0.96, 0.99, and 0.94, respectively, for observer 2.


CONCLUSIONS
There is greater inter- than intraobserver agreement for CT vascular perfusion measurements of primary colorectal cancer, which must be addressed for reliable clinical application in therapeutic monitoring.
Intestinal Imaging Centre, St. Mark's Hospital, Watford Rd., Level 4V, Harrow, Middlesex, HA1 3UJ, United Kingdom.
Vicky
V
Goh
Steve
S
Halligan
Jo-Ann
JA
Hugill
Paul
P
Bassett
Clive I
CI
Bartram
D000230:Adenocarcinoma / Q000098:blood supply* / Q000000981:diagnostic imaging*; D000368:Aged; D015179:Colorectal Neoplasms / Q000098:blood supply* / Q000000981:diagnostic imaging*; D003287:Contrast Media; D005260:Female; D006801:Humans; D007479:Iopamidol; D008297:Male; D015588:Observer Variation; D010539:Permeability; D012039:Regional Blood Flow; D014057:Tomography, X-Ray Computed / Q000379:methods*
D003287:Contrast Media; D007479:Iopamidol