Mark Wax MD, Arie Kaufman PhD, Jerome Liang PhD, and Kevin Kreeger MS Jerome Liang PhD, and Kevin Kreeger MS Advancing Virtual Colonoscopy to Practice

Introduction Cited Limitations Approach to Overcoming Obstacles Conclusions Advancing Virtual Colonoscopy to Practice

Colorectal Cancer Screening Guidelines (Gastroenterology, 1997) Screening Modality –Safe –Acceptable –Available –Cost Effective

An alternative endoscopic procedure for examining the inner surface of the human colonAn alternative endoscopic procedure for examining the inner surface of the human colon Overcoming disadvantages of existing proceduresOvercoming disadvantages of existing procedures 3D Virtual Colonoscopy

40 sec CT scan of patient’s abdomen Reconstruction of 3D colon model Pre-processing of colon model Interactive navigation inside colon Virtual Colonoscopy Procedure

Introduction Cited Limitations Approach to Overcoming Obstacles Conclusions Advancing Virtual Colonoscopy to Practice

New England Journal of Medicine (Nov 11, 1999) “A Comparison of Virtual and Conventional Colonoscopy for the Detection of Colorectal Polyps” H. Fenlon et. al, Boston University “Virtual Colonoscopy - Promising but Not Ready for Widespread Use” J. Bond, Minneapolis VA

Cited Limitations Patient Preparation –Bowel Cleansing Technique –Gas distention of colon –Time to process data/images to determine whether optical colonoscopy is required

Cited Limitations Image Interpretation –Time consuming –Steep learning curve –Technically inadequate studies Retained stool/fluid Contracted segments –Sensitivity/specificity

Cited Limitations Cost –Expensive scanning hardware –Needs to be less than optical colonoscopy

Introduction Cited Limitations Approach to Overcoming Obstacles Conclusions Advancing Virtual Colonoscopy to Practice

Bowel Cleansing Contrast Agents - Barium Sulfate, Gastrograffin Low residue diet Electronic Cleansing

Inner View of the Colon

Technique Colon Distention –CO 2 instead of room air  Fast reabsorbtion  Increased patient comfort Collapsed colon segments –Glucagon –Supine and Prone Views

Image Interpretation Steep Learning Curve –Similar to any new technology or procedure Virtual fly-through interface mimics optical colonoscopy

User Interface

Time to Process Data and Interpret Images Volume rendering with SGI and PC platforms Navigation –Guided using colon centerline –Interactive with the click of a mouse

Sensitivity/Specificity Stool/Fluid tagging Electronic Cleansing Electronic Biopsy

Costs Estimated cost - $200-$300 –Less than Medicare reimbursement for Abdominal and Pelvic CT ($410) –Less than Physician charges for optical colonoscopy ($700) Only requires 10 minutes of CT scanning time Increased utilization of CT scanners

Introduction Cited Limitations Approach to Overcoming Obstacles Conclusions Advancing Virtual Colonoscopy to Practice

Virtual Colonoscopy System Technical Advances –Speed –Automation –Comfort –Cost effective Future –System still evolving, not yet frozen –Large scale clinical trial