One study evaluating CTU in detecting bladder cancer in patients with hematuria or surveillance showed 13 of 710 false-negatives and 47 of 710 false-positives [36]. Of the false-negatives, 11 of 13 were due to limitations of the technique because the lesions were not visible in retrospect, whereas cystoscopy showed carcinoma in situ or urothelial erythema. Two false- negatives were related to technical factors, one case was related to a large postvoid residual with suboptimal opacification of the bladder, and one case was related to bilateral hip arthroplasties with artifacts obscuring the bladder. False-positive results were due to interpretation errors, most caused by benign prostatic hypertrophy mimicking a bladder lesion, followed by bladder trabeculation, post-treatment changes, and intravesical blood clots. According to experts in the field, a small percentage of patients with bladder cancer will also develop UTUC, necessitating a comprehensive examination of the urothelium [5]. One effective approach to detecting UTUC is the use of an abdomen-pelvis CTU protocol. In recent years, CTU and MRU have largely replaced IV urography (IVU) for evaluating the renal collecting systems and ureters [37,38]. These cross-sectional techniques offer several Pretreatment Staging of Urothelial Cancer advantages, such as the ability to visualize small masses, which may be obscured on excretory urography due to contrast material or bowel gas, identify focal wall thickening, and distinguish enhancing tumors from nonenhancing calculi or blood clots [5,37]. Additionally, CTU and MRU can evaluate nonfunctioning/obstructed kidneys that would not excrete the contrast medium required for excretory urography. Based on these strengths, Jinzaki et al [37] suggest that CTU should be the initial examination for high-risk patients, whereas Cohan et al [39] concluded that CTU can detect more bladder cancers than excretory urography.
Pretreatment Staging of Urothelial Cancer. One study evaluating CTU in detecting bladder cancer in patients with hematuria or surveillance showed 13 of 710 false-negatives and 47 of 710 false-positives [36]. Of the false-negatives, 11 of 13 were due to limitations of the technique because the lesions were not visible in retrospect, whereas cystoscopy showed carcinoma in situ or urothelial erythema. Two false- negatives were related to technical factors, one case was related to a large postvoid residual with suboptimal opacification of the bladder, and one case was related to bilateral hip arthroplasties with artifacts obscuring the bladder. False-positive results were due to interpretation errors, most caused by benign prostatic hypertrophy mimicking a bladder lesion, followed by bladder trabeculation, post-treatment changes, and intravesical blood clots. According to experts in the field, a small percentage of patients with bladder cancer will also develop UTUC, necessitating a comprehensive examination of the urothelium [5]. One effective approach to detecting UTUC is the use of an abdomen-pelvis CTU protocol. In recent years, CTU and MRU have largely replaced IV urography (IVU) for evaluating the renal collecting systems and ureters [37,38]. These cross-sectional techniques offer several Pretreatment Staging of Urothelial Cancer advantages, such as the ability to visualize small masses, which may be obscured on excretory urography due to contrast material or bowel gas, identify focal wall thickening, and distinguish enhancing tumors from nonenhancing calculi or blood clots [5,37]. Additionally, CTU and MRU can evaluate nonfunctioning/obstructed kidneys that would not excrete the contrast medium required for excretory urography. Based on these strengths, Jinzaki et al [37] suggest that CTU should be the initial examination for high-risk patients, whereas Cohan et al [39] concluded that CTU can detect more bladder cancers than excretory urography.