Feasibility of the virtual dissection technique as the standard reading method in computed tomography colonography

Abstract

OBJECTIVES: In general, computed tomography (CT) colonography is interpreted using a combination of 2D images with multiplanar reformats and 3D endoluminal reconstruction (virtual endoscopic images). This study evaluated the use of the virtual dissection technique as the standard reading method in CT colonography as an alternative to virtual endoscopic images for screening of colorectal neoplasms.
METHODS: Forty-six colorectal neoplasms in 15 patients diagnosed using preoperative CT colonography and optical colonoscopy were included in this study, and three readers evaluated virtual dissection images acquired using three different workstations (Virtual Place: AZE; Ziostation: Ziosoft; SYNAPSE VINCENT: Fujifilm Medical). To compare the virtual dissection images with optical colonoscopic images, each neoplasm was scored on a 5-point Likert scale ranging from 1 (lowest score: neoplasm was not detected) to 5 (highest score: neoplasm was easily detected and resembled the lesion observed in the optical image.
RESULTS: The mean scores of the three workstations were 2.70±1.01, 2.78±0.93, and 2.28±1.00; the score of one workstation was significantly lower compared with those of the other two workstations. The mean numbers of lesions with a score >3 were 27.3, 29.0, and 19.0; the mean for one workstation was significantly lower than those for the other two workstations.
In some cases, one workstation falsely identified a true polyp in the stool tagged with contrast material as stool; however, the other two workstations identified it correctly.
CONCLUSION: Tumor shape and electronic cleansing effects differ between different workstations because of the differences in the reformat algorithm employed. These results suggest that polyp detectability of the virtual dissection technique varies depending on the workstation used. Therefore, we conclude that the virtual dissection technique is not suitable for use as a standard reading method for the interpretation of CT colonography.