CT Colonography clinical trial under IRB approval. True 3D Viewer 1.0 is 510K cleared by FDA; development and 510K clearance in process for all other applications

Luminary Site: UCSF / SFVAMC

Principal Investigator: Judy Yee, MD. FACR. A pioneer in CT Colonography (Virtual Colonoscopy), Dr. Yee is Professor and Vice Chair of Radiology and Biomedical Imaging. She is Chief of Radiology at the San Francisco VA Medical Center.

Clinical Problem 

Current CT Colonography (CTC) visualization techniques have limitations in representing the complex 3D relationships present in the colon, a key factor that facilitates polyp detection. To successfully identify a polyp, radiologists’ must integrate a series of 2D images in their mind and cognitively extract the relevant 3D relationships that define the colon, neighboring anatomy and polyps.  In complex cases, they must visually map 2 or more views of the same data, attempting to recognize similarities between views and confirm that the feature of interest is a true polyp.


  1. Improve anatomic understanding. The  t3D-CTC protocol can provide a better understanding of colon lumen morphology because it integrates all three dimensions and corresponding depth cues in a single view.
  2. Increase polyp sensitivity. The t3D-CTC solution can provide an enhanced visualization and detection tool because the accurate depiction of depth information provided by t3D enhances the features that define a polyp (shape, size, height and edges). 
  3. Reduce false-positive findings. With a hand-directed stylus, the reader can interact with a 2D MPR image cross section over a 3D view of a polyp or colon segment to evaluate underlying tissue density.
  4. Increase reader tolerance to image noise. t3D-CTC allows viewers to clearly identify 3D structures, which would have been difficult to discern from noise without accurate depiction of depth information provided by t3D. 
  5. Reduce interpretation time. The t3D-CTC navigation strategy can eliminate anterograde and retrograde endoluminal navigation, as well as reduce reader tracking of the colon when there are redundant segments, aberrant anatomy or collapsed segments.