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.
Goh
Vicky
V
Intestinal Imaging Centre, St. Mark's Hospital, Watford Rd., Level 4V, Harrow, Middlesex, HA1 3UJ, United Kingdom.
Halligan
Steve
S
Hugill
Jo-Ann
JA
Bassett
Paul
P
Bartram
Clive I
CI
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