Volumetric Analysis of Colonic Distention According to Patient Position at CT Colonography: Diagnostic Value of the Right Lateral Decubitus Series

Abstract

Purpose To compare total colonic gas volume and segmental luminal distention according to patient position at CT colonography (CTC), and determine which two views should constitute the routine protocol. Methods Volumetric analysis was retrospectively performed on CTC examinations from 146 adults (mean age, 59.2 years; 81M/65F; mean BMI, 30.9) where supine, prone, and right lateral decubitus series were sequentially obtained using continuous low-pressure CO2 insufflation. Total colonic gas volumes were assessed using a novel automated volumetric tool. In addition, two radiologists scored distention by segment using a 4-point scale (4=Optimal/3=Adequate/2=Inadequate/1=Collapsed). Results Mean colonic gas volume (±SD) for supine, prone, and decubitus positioning was 1,617±567 ml, 1441±505 ml, and 1901±627 ml, respectively (p<0.001). Colonic volume was highest on the right lateral decubitus series in 73.3% (107/146) and lowest in 6.2% (9/146) of cases, whereas the prone series was highest in 0.7% (1/146) and lowest in 73.3% (107/146) of cases. Overall mean segmental reader scores and % inadequate/collapsed for supine, prone, and decubitus positions were 3.48/3.33/3.71, and 10.4%/12.1%/4.2%, respectively (p<0.001). The only mean segmental scores below 3.0 were the sigmoid on supine (2.68) and prone (2.58), compared with 3.23 on decubitus (p<0.001). Improvement in both decubitus and supine distention over prone increased further with increasing BMI (p<0.001). Conclusions The right lateral decubitus position consistently yields the best colonic distention at CTC, and significantly improves sigmoid evaluation. Prone distention was the worst, particularly as BMI increased. Routine supine and decubitus positioning should be considered for standard CTC protocols, particularly in obese individuals. Automated volumetric analysis provides for rapid objective assessment of colonic distention.

Effect of Reducing Abdominal Compression during Prone CT Colonography on Ascending Colonic Rotation during Supine-to-Prone Positional Change

“…Furthermore, our study underscores the general importance of confirming the mobility or lack of mobility of a suspected lesion on CTC by careful topographic comparisons with other available fixed structures, such as colonic folds, teniae or diverticula, using both, 3-dimensional and 2-dimensional views rather than a simple comparison of apparent lesion locations on 2-dimensional images. This careful interpretive approach is particularly important, since CTC can be obtained not only in the standard supine-prone positions but also in alternative positions, including lateral decubitus positions ( 16 17 18 19 ). The degree and pattern of colonic movement caused by lateral decubitus positions of patients would likely differ from standard supine-to-prone change; hence, comparing lesion locations between different sets of CTC images is even more difficult.…”

Objective and Subjective Intrapatient Comparison of Iohexol Versus Diatrizoate for Bowel Preparation Quality at CT Colonography

“…The total volume and mean attenuation of the residual luminal colonic fluid for each patient were derived using an automated quality assessment (QA) tool available on a beta version of our CTC software system (V3D Colon, Viatronix) that provides the luminal fluid and gas volumes [5, 6, 19]. This portion of the study was conducted by one of the co-authors (B.J.…”

Automatic Electronic Cleansing in Computed Tomography Colonography Images using Domain Knowledge

“…The parameters Low Threshold, High Threshold and Gaussian sigma (σ) with values in the range 40-50, 100-120 and 1.4 respectively resulted in accurate boundary detection between contrast-colon wall. Then colon blobs are identified using connected component labeling method and finally blobs diameter measuring <2 cm are discarded using knowledge of colon distention grading (Pickhardt et al, 2014). Then the segmented blob region is filled with the original slice voxel intensities so that colon content is absolutely preserved without loss of tissue details.…”