Virtual CT cystoscopy - Color mapping of bladder wall thickness

RATIONALE AND OBJECTIVES. TO improve the conspicuity of bladder tumors in a virtual environment, we developed an algorithm for color mapping the thick ness of the bladder wall. The purpose of this study was to demonstrate the feasibility of this algorithm as a component of virtual CT cystoscopy, METHODS. Five subjects with a history of superficial transitional-cell carc inoma of the bladder underwent helical CT scanning after insufflation of th e bladder with air. Source images were transformed into three-dimensional m odels, and the thickness of the bladder wall was demarcated by using a new computer algorithm and a fixed color scale. Results were compared with thos e obtained by conventional cystoscopy, RESULTS. Three tumors, one site of benign wall thickening, and normal wall thickness were correctly identified by using axial source images and virtua l cystoscopy with color mapping. CONCLUSIONS. Color mapping of bladder wall thickness is feasible and demons trates both normal and thickened urothelium. Its value in identification of small or sessile tumors will require further trials.