title: Electronic cleansing for dual-energy CT colonography based on material decomposition and virtual monochromatic imaging.
abstract: CT colonography (CTC) uses orally administered fecal-tagging agents to enhance retained fluid and feces that would otherwise obscure or imitate polyps on CTC images. To visualize the complete region of colon without residual materials, electronic cleansing (EC) can be used to perform virtual subtraction of the tagged materials from CTC images. However, current EC methods produce subtraction artifacts and they can fail to subtract unclearly tagged feces. We developed a novel multi-material EC (MUMA-EC) method that uses dual-energy CTC (DE-CTC) and machine-learning methods to improve the performance of EC. In our method, material decomposition is performed to calculate water-iodine decomposition images and virtual monochromatic (VIM) images. Using the images, a random forest classifier is used to label the regions of lumen air, soft tissue, fecal tagging, and their partial-volume boundaries. The electronically cleansed images are synthesized from the multi-material and VIM image volumes. For pilot evaluation, we acquired the clinical DE-CTC data of 7 patients. Preliminary results suggest that the proposed MUMA-EC method is effective and that it minimizes the three types of image artifacts that were present in previous EC methods.
authors.affiliation: 3D Imaging Research, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 25 New Chardon Street, Suite 400C, Boston, MA 02114, USA.
authors.forename: Rie
authors.initials: R
authors.lastname: Tachibana
authors.affiliation: 3D Imaging Research, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 25 New Chardon Street, Suite 400C, Boston, MA 02114, USA.
authors.forename: Janne J
authors.initials: JJ
authors.lastname: Näppi
authors.affiliation: Seoul National University Hospital, 101 Daehangno, Chongno-gu, Seoul 110-744, Republic of Korea.
authors.forename: Se Hyung
authors.initials: SH
authors.lastname: Kim
authors.affiliation: 3D Imaging Research, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, 25 New Chardon Street, Suite 400C, Boston, MA 02114, USA.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yoshida
keywords: Colon; dual-energy CT; random forest; virtual cleansing; virtual colonoscopy
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