RSNA 2015

Abstract Archives of the RSNA, 2015


SST14-08

Quality Assurance in a Multicenter Trial Evaluating Quantitative CT Perfusion Imaging as a Biomarker of Patient Outcome in Ovarian Cancer Chemotherapy: An ECOG-ACRIN and NRG GOG Study

Friday, Dec. 4 11:40AM - 11:50AM Location: S403B



Ting-Yim Lee, MSc, PhD, London, ON (Presenter) Research Grant, General Electric Company Royalties, General Electric Company
Chaan Ng, MD, Houston, TX (Abstract Co-Author) Nothing to Disclose
Susanna I. Lee, MD, PhD, Boston, MA (Abstract Co-Author) Nothing to Disclose
Mark A. Rosen, MD, PhD, Philadelphia, PA (Abstract Co-Author) Nothing to Disclose
Feng Su, PhD, London, ON (Abstract Co-Author) Nothing to Disclose
Joseph Bauza, Philadelphia, PA (Abstract Co-Author) Nothing to Disclose
Zheng Zhang, PhD, Providence, RI (Abstract Co-Author) Nothing to Disclose
Susan M. Edwards, MD, Oklahoma City, OK (Abstract Co-Author) Nothing to Disclose
Therese M. Weber, MD, Birmingham, AL (Abstract Co-Author) Nothing to Disclose
Background

ACRIN 6695's primary objective was to determine whether CT perfusion (CTP) parameters are prognostic of progression-free survival at 6 months in a cohort of patients from the GOG-262 trial. The latter is a phase III trial on advanced stage ovarian cancer comparing standard to dose-dense paclitaxel/carboplatin with 91% of cohort also receiving bevacizumab. Multivariate analysis of ACRIN 6695 demonstrated association of CTP parameters with patient outcome. 76 subjects underwent 3 CTP studies comprised of dynamic contrast enhanced using a two-phase scanning protocol: 24 images at 2.8 s intervals followed by 8 images at 15 s intervals acquired using 120 kV and 50 mAs each image. Axial shuttle scanning mode was allowed but not required. To ensure protocol compliance and uniform image quality, a CT scanner certification process was implemented. Scanner accreditation required that images of a water phantom scan acquired using the trial CTP protocol be submitted to a central core lab where they were evaluated for the following variables: image interval, CT noise, spatial uniformity and temporal stability of CT number.

Evaluation

19 CT scanners from 4 vendors were accredited. The image intervals in both CTP phases were correct in all scanners. CT noise normalized to 5 mm slice thickness was 10.1±1.6 HU. Spatial uniformity and temporal stability was 0.94±0.54 and 0.44±0.15 HU respectively. Both CT noise and spatial uniformity were within 15% of vendor specifications for all accredited scanners.

Discussion

Important factors affecting the accuracy and precision of CTP derived functional parameters include image intervals, CT noise, spatial uniformity and temporal stability of CT numbers. The accreditation process for the ACRIN 6695 evaluated specifically these factors using a practical process which can be implemented by scanning a routine quality control water phantom already present at the site with the specified protocol.

Conclusion

The ACRIN 6695 trial has demonstrated that CT scanner quality assurance for abdominopelvic CTP can be successfully accomplished with sufficient uniformity across multiple sites and scanner platforms to yield positive results in a multicenter biomarker trial.

Honored Educators

Presenters or authors on this event have been recognized as RSNA Honored Educators for participating in multiple qualifying educational activities. Honored Educators are invested in furthering the profession of radiology by delivering high-quality educational content in their field of study. Learn how you can become an honored educator by visiting the website at: https://www.rsna.org/Honored-Educator-Award/

Susanna I. Lee, MD, PhD - 2013 Honored Educator