Vicky Joo-Lin Goh MBBCHIR, Presenter: Nothing to Disclose

Steve Halligan MD, Abstract Co-Author: Nothing to Disclose

Jo Ann Balmer, Abstract Co-Author: Nothing to Disclose

Clive I. Bartram MD, Abstract Co-Author: Nothing to Disclose

While inter- and intra-observer agreement has been determined for computed tomography (CT) assessment of colorectal tumour perfusion, no study has focussed on the repeatability of the technique itself.

Following ethical approval, 7 patients with colorectal cancer were examined prospectively using 4-detector row CT. A dynamic study (cine mode; 5mm collimation) was acquired through the tumour epicenter following intravenous contrast administration (100mls Niopam 340; 5ml/s), followed by a diagnostic study. The perfusion study was then subsequently repeated on a separate occasion (range 2 hours to 2 days) using identical technical parameters. Tumour blood volume, flow, mean transit time, and permeability were determined by a single observer using proprietary software and compared using Bland-Altman test statistics in order to determine agreement between the two sets of measurements.

The mean (SD) of blood volume, flow, transit time and permeability were 3.8 (1.1) ml/100g tissue; 69.8 (30.9) ml/100g tissue/min; 4.6 (1.6) seconds and 19.5 (7.8) ml/100g tissue/ml respectively for the first set of measurements, and 3.8 (1.3) ml/100g tissue; 63.1 (32.7) ml/100g tissue/min; 6.1 (3.5) seconds and 18.2 (9.4) ml/100g tissue/min for the second set of measurements. The mean difference (95% limits of agreement) was +0.12 ml/100g tissue (-1.4 to +1.6); +6.7 ml/100g tissue/min (-35.6 to +48.9); -1.5 seconds (-7.9 to +4.9); and +1.3 ml/100g tissue/min (-9.1 to +11.8) for blood volume, flow, transit time, and permeability respectively.

Repeatability of CT perfusion measurements is clinically acceptable and unlikely to significantly confound comparison of sequential measurements.

Goh, V, Halligan, S, Balmer, J, Bartram, C, Measurement of Colorectal Cancer Perfusion Using Multi-Detector Computed Tomography: Repeatability and Clinical Implications.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4405186.html