Feasibility of remote CT colonography at two rural Native American medical centers.

OBJECTIVE: Fort Defiance Indian Hospital and Tuba City Regional Health Care Center are two rural hospitals with limited availability of optical colonoscopy (OC) and other methods of colorectal cancer screening. Our goals were to determine whether adequate examinations could be obtained with remote supervision after brief onsite instruction and to share lessons learned in our experience with a remote CT colonography (CTC) screening program. MATERIALS AND METHODS: After brief onsite instruction, including performing a CTC examination on a volunteer to train the CT technologists, both sites began performing CTC using standard bowel preparation, fecal tagging, automatic insufflation, and low-dose technique. Studies were transferred to the University of Arizona Hospital for image quality assessment of stool, residual fluid, distention, and interpretation, with reports returned via the teleradiology information system. Clinical follow-up was performed on those patients referred for polypectomy or biopsy. RESULTS: Three hundred twenty-one subjects underwent CTC, including 280 individuals referred for screening examinations (87%). Ninety-two percent of subjects (295/321) had acceptable amounts of residual stool, 91% (293/321) had acceptable levels of fluid, and 92% (294/321) had acceptable distention. Fourteen percent (44/321) of CTC patients had polyps 6 mm or larger in size, with a positive predictive value of 41% for those who subsequently underwent colonoscopy-polypectomy (11/27). CONCLUSIONS: CTC can be introduced to rural underserved communities, performed locally, and interpreted remotely with satisfactory performance, thereby increasing colorectal cancer screening capacity. Important aspects of implementation should include technologist training, referring physician education, careful attention to image transmission, and clearly defined methods of communication with patients and referring providers.

Comparison of the accuracy of CT volume calculated by circumscription to prolate ellipsoid volume (bidimensional measurement multiplied by coronal long axis).

RATIONALE AND OBJECTIVES: Tumor volume is one of the most important factors in evaluating the response to treatment of patients with cancer. The objective of this study was to compare computed tomographic (CT) volume calculation using a semiautomated circumscribing tracing tool (manual circumscription [MC]) to prolate ellipsoid volume calculation (PEVC; bidimensional measurement multiplied by coronal long axis) and determine which was more accurate and consistent. MATERIALS AND METHODS: The study included six patients with nine neoplasms, six phantoms, and two radiologists. The neoplasms and phantoms of varying sizes and shapes were imaged using multidetector CT scanners, with slice thicknesses ranging from 0.5 to 3 mm. Measurements were performed using a TeraRecon 3D workstation. Each lesion and phantom was manually circumscribed, and its three dimensions were measured. The measurements were repeated 2 weeks later. RESULTS: MC of the phantoms deviated from their true volumes by an average of 3.0 +/- 1%, whereas PEVC deviated by 10.1 +/- 3.99%. MC interobserver readings varied by 1.2 +/- 0.6% and PEVC by 4.8 +/- 3.3%. MC intraobserver readings varied by 1.95 +/- 1.75% and PEVC by 2.5 +/- 1.55%. Patient tumor volume predicted by MC and PEVC varied greatly; MC interobserver readings differed by 3.3 +/- 2.1% and PEVC by 20.1 +/- 10.6%. MC intraobserver readings varied by 2.5 +/- 1.9% and PEVC by 5.5 +/- 3.2%. Variability was greater for complex shapes than for simple shapes. Bidimensional analysis demonstrated an interobserver difference of 12.1 +/- 8.7% and an intraobserver difference of 5.05 +/- 3.3%. These results demonstrate large interobserver and intraobserver variability. Variability was greater for complex shapes than for simple shapes. CONCLUSION: MC of neoplasms provided more accurate and consistent volume predictions than PEVC. More complicated shapes demonstrated the superiority of MC over PEVC.