Objective: Bladder cancer is the ninth cause of cancer deaths and has high recurrence rate after resection of the tumors. Cystoscopy is the current most accurate method for investigating the bladder abnormalities. However, it is expensive, uncomfortable and invasive. It is possible to induce bleeding, urinary-tract infection and even puncture of bladder. Advances in medical imaging and computer technologies make virtual cystoscopy a potential alternative. Methods: Computed tomography (CT) and magnetic resonance imaging (MR/) are the preferred imaging modalities for virtual cystoseopy to get clear structural images or (and) functional images of the bladder. The boundary of bladder is segmented manually or automatically, and then the bladder is reconstructed and displayed by surface rendering. Useful features are extracted from the images and expressed o nthe reconstructed bladder to provide more valuable diagnosis information for doctors. Results: Comparing with conventional cystuscopy, virtual cystuscopy is noninvasive, more convenient, flexible and can provide more useful diagnosis information as well. Conclusions: Virtual cystoscopy is a promising method of detection and reexamination of bladder cancer. So far, more researches are needed for the virtual cystoscopy before clinical application. It clinical and commercial value are under investigation.

Objective To study the compliance of examinees,and effectiveness of colorectal distension with partially automated and individualized insufflation of air for dual-energy CT colonography.Methods Forty-six healthy adult volunteers without history of conditions affecting gastrointestinal motor function were enrolled in this study.One day before CT examination,volunteers were asked to orally administered 60 mL 4% diatrizoate meglumine five times for fecal tagging.Air was insufflated by using an inflator in a partially automated and individualized manner.The volunteers were initially asked to assume the right lateral decubitus position,then slowly turn to the supine position.Insufflation rate began at 1.5 L/min,and decreased to 0.5 L/min at later stage.The necessity and volume of air insufflation were decided according to effectiveness of colorectal distension on CT scout images,self-reported sensation of volunteers,and intestinal pressure.Dual-energy CT scanning was performed,and dual-energy blended images were acquired.Compliance of volunteers was statistically analyzed.The effectiveness of colorectal segments distension was statistically analyzed by using Kruskal-Wallis H test.Results No abdominal pain,bloating,nausea or vomiting were noted in the 46 volunteers.All volunteers easily accepted colorectal insufflation of air,with grade 1 compliance.The effectiveness of colorectal distension of grades 1,2,3 and 4 were 0%,2.1%,5.1% and 92.8%,respectively.The difference of effectiveness of colorectal segments distension had no statistical significance(χ2=6.19,P=0.288).The effectiveness of insufflation was poor in 6 colorectal segments,including 2 in sigmoid colon and 2 in rectum.Effectiveness of insufflation was suboptimal in 14 colorectal segments,including 4 in descending colon,4 in sigmoid colon,and 3 in rectum.Conclusion Compliance of examinees with partially automated and individualized insufflation of air for dual-energy CT colonography is excellent,with good effectiveness of colorectal distension.

Objective To comparative study the effect on colorectal cleansing of CT colonography with gulping down 10 mg bisacodyl before or 1 h after oral taking 2 liter polyethylene glycol .Methods Forty participants with informed consent were appor‐tioned to group A ,group B randomly ,20 cases in each group .On the day before CT colonography ,participants in group A oral took 20 mL of 40% W/V barium sulfate prior to 3 mealtime ,and 20 mL of 60% diatrizoate meglumine diluted in 250 mL of water after supper ,then gulped down 10 mg bisacodyl enteric‐coated tablets 1 hour before oral taking 2 liter polyethylene glycol electrolyte so‐lution .Participants in group B were the same as that in group A ,with the exception of gulping down 10 mg bisacodyl enteric‐coated tablets 1 hour after oral taking 2 liter polyethylene glycol electrolyte solution .Cleansing efficacy of stool and fluid ,and attenuation value of remainder fluid between the two groups were analyzed statistically .Results In group A ,score of cleansing efficacy of stool (1 .96 ± 0 .11) was lower than that in group B (2 .01 ± 0 .12) ,segments with good cleansing efficacy of stool (87/120 segments , 72 .50% ) was higher than that in group B (83/120 segments ,69 .17% ) ,the difference was not statistically significant (P>0 .05) .In group A ,score of cleansing efficacy of fluid (1 .50 ± 0 .06) was lower than that in group B (1 .53 ± 0 .06) ,segments with good cleansing efficacy of fluid(113/120 segments ,94 .17% ) was higher than that in group B (111/120 segments ,92 .50% ) ,the differ‐ence was not statistically significant (P>0 .05) .Attenuation value of remainder fluid [(729 ± 29)HU ] in group A was higher than that in group B[(653 ± 25)HU] ,the difference was statistically significant(P<0 .05) .Conclusion Gulping down 10 mg Bisacodyl before or after oral taking 2 liter polyethylene glycol has no effect on cleansing of stool and fluid ,with good cleansing efficacy .The former has better cleansing efficacy of fluid ,is beneficial to detecting polyps for CT colonography .