Basic Study
Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Radiol. Mar 28, 2018; 10(3): 24-29
Published online Mar 28, 2018. doi: 10.4329/wjr.v10.i3.24
Effect of varying computed tomography acquisition and reconstruction parameters on semi-automated clot volume quantification
Audrey E Kaufman, Alison N Pruzan, Ching Hsu, Sarayu Ramachandran, Adam Jacobi, Zahi A Fayad, Venkatesh Mani
Audrey E Kaufman, Alison N Pruzan, Sarayu Ramachandran, Adam Jacobi, Zahi A Fayad, Venkatesh Mani, Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
Audrey E Kaufman, Alison N Pruzan, Sarayu Ramachandran, Zahi A Fayad, Venkatesh Mani, Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, Hess Center for Science and Medicine, New York, NY 10029, United States
Ching Hsu, Daiichi Sankyo Inc., Basking Ridge, NJ 07920, United States
Author contributions: All authors designed the experiment; Kaufman AE, Pruzan AN, Ramachandran S and Mani V performed the experiment; Kaufman AE performed the image analysis; Pruzan AN and Hsu C performed statistical analysis; Kaufman AE and Mani V wrote the draft of the manuscript; all authors critically reviewed the manuscript.
Institutional review board statement: As this is an in-vitro study, institutional review board approval was not required.
Conflict-of-interest statement: Hsu C is an employee of Daiichi Sankyo Inc; all other authors have no conflicts to disclose.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Venkatesh Mani, PhD, Associate Professor, Director, Department of Radiology, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY 10029, United States. venkatesh.mani@mountsinai.org
Telephone: +1-212-824844 Fax: +1-240-3688096
Received: February 9, 2018
Peer-review started: February 10, 2018
First decision: March 12, 2018
Revised: March 14, 2018
Accepted: March 19, 2018
Article in press: March 20, 2018
Published online: March 28, 2018
Abstract
AIM

To examine effects of computed tomography (CT) image acquisition/reconstruction parameters on clot volume quantification in vitro for research method validation purposes.

METHODS

This study was performed in conformance with HIPAA and IRB Regulations (March 2015-November 2016). A ten blood clot phantom was designed and scanned on a dual-energy CT scanner (SOMATOM Force, Siemens Healthcare GmBH, Erlangen, Germany) with varying pitch, iterative reconstruction, energy level and slice thickness. A range of clot and tube sizes were used in an attempt to replicate in vivo emboli found within central and segmental branches of the pulmonary arteries in patients with pulmonary emboli. Clot volume was the measured parameter and was analyzed by a single image analyst using a semi-automated region growing algorithm implemented in the FDA-approved Siemens syngo.via image analysis platform. Mixed model analysis was performed on the data.

RESULTS

On the acquisition side, the continuous factor of energy showed no statistically significant effect on absolute clot volume quantification (P = 0.9898). On the other hand, when considering the fixed factor of pitch, there were statistically significant differences in clot volume quantification (P < 0.0001). On the reconstruction side, with the continuous factor of reconstruction slice thickness no statistically significant effect on absolute clot volume quantification was demonstrated (P = 0.4500). Also on the reconstruction side, with the fixed factor of using iterative reconstructions there was also no statistically significant effect on absolute clot volume quantification (P = 0.3011). In addition, there was excellent R2 correlation between the scale-measured mass of the clots both with respect to the CT measured volumes and with respect to volumes measure by the water displacement method.

CONCLUSION

Aside from varying pitch, changing CT acquisition parameters and using iterative reconstructions had no significant impact on clot volume quantification with a semi-automated region growing algorithm.

Keywords: Computed tomography angiography, Radiographic phantom, Computer-assisted image analysis, Pulmonary embolism, Thrombolytic therapy

Core tip: This in vitro study showed that with the exception of pitch, varying the computed tomography pulmonary angiography image acquisition parameters and using iterative reconstructions had no significant impact on clot volume quantification when using a semi-automated region growing algorithm. This finding is applicable to validating core lab analysis in multicenter clinical trials with imaging endpoints, where a wide range of acquisition and reconstruction parameters are used.