Wenli Cai PhD, Presenter: Nothing to Disclose

Yoshiaki Yanagikawa, Abstract Co-Author: Nothing to Disclose

Koichi Nagata MD, Abstract Co-Author: Research Consultant, Ajinomoto Co, Inc

Hiroyuki Yoshida PhD, Abstract Co-Author: Patent holder, Hologic, Inc Patent holder, Median Technologies

The purpose of this study was to evaluate a novel electronic cleansing (EC) method, structural-analysis cleansing (SA-Cleansing), in virtually cleansing non-cathartic and cathartic CT colonography (CTC). We assessed whether, after the application of SA-Cleansing, the polyps submerged in tagged fecal materials had the same appearance as that of the “air-exposed” polyps in both cathartic and no-cathartic CTC.

Fifty non-cathartic and 50 cathartic CTC cases were retrospectively collected for this study. Each subject had video-assisted optical colonoscopy (OC) as reference standard. The detected polyps on OC were categorized based upon their morphologic and pathologic findings. Five pathology groups were provided, including P1: 6-9 mm adenoma, P2: > 9 mm adenoma, P3: cancer, P4: others, and P5: hyperplasic. Morphology groups were three-fold: polypoid, flat, and advance cancer. These cases were subjected to the SA-cleansing. A volume-of-interest (VOI) was extracted to encompass each submerged as well as air-exposed polyp from CTC images. These VOIs were presented to two observers in a random order. The observer rated the confidence level with a continuous scale ranging from 1 (virtually cleansed polyp) to 5 (air-exposed polyp).

In 50 cathartic CTC cases, 49 polyps were detected including 25 submerged and 24 non-submerged polyps. In 50 non-cathartic CTC cases, 27 polyps were detected, of which 13 were submerged and 14 were non-submerged polyps. The average score for non-cathartic CTC polyps was 3.71±1.74, in which submerged and non-submerged polyps scored 3.68±1.84 and 3.75±1.68, respectively. For the non-cathartic CTC cases, the average score was 3.52±1.56, in which submerged and non-submerged polyps scored 3.09±1.51 and 3.92±1.56, respectively. For the 5 pathology groups, the average score ranged from 3.14 to 4.55, with P5 having the lowest score and P2 having the highest score for both submerged and non-submerged groups. For the 3 morphology groups, the average score ranged from 3.17 to 4.02, with flat lesions having the lowest score of 3.17 and polyploidy and cancer having the same mean score of 4.00.

The submerged polyps cleansed by SA-Cleansing had no significant difference in visual assessment from non-submerged polyps.

Our new EC method with reduced subtraction artifacts can provide diagnostically useful visualization of the colonic lumen in CTC examinations.

Cai, W, Yanagikawa, Y, Nagata, K, Yoshida, H, Evaluation of the Conspicuity of Polyps Cleansed by Structural Analysis Method in Noncathartic CT Colonography.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8016375.html