Single-bolus computed tomography urography (CTU)is a recently developed one-stop imaging examination for diagnosis of urinary tract diseases, including urinary malignancies. However, single-bolus CTU uses two post- contrast phases (i.e.: nephrographic and excretory phases) for diagnosis of urinary tract diseases. A further-developed split-bolus CTU uses solitary post-contrast phase containing mixed information of nephrographic and excretory phases for diagnosis of urinary tract disease; however, whether split-bolus CTU has similar high diagnostic values for urinary malignancies remains unaddressed. Thus, the aim of this study is to compare the diagnostic performance between single-bolus and split-bolus CTU for diagnosing urinary malignancies. This study will enroll 352 patients from two hospitals if they fit the including criteria including aged > 40 years old, presenting with gross hematuria or having urinary malignancies histories, normal renal function (i.e.: estimated glomerular filtration rate > 60 mL/min/1.73 m2, no allergic history to iodinated contrast medium and no pregnancy). All enrolled patients will be randomized to undergo split-bolus and single-bolus CTU in 1: 1 manner. Two radiologists will read CTU images independently using a standardized recording sheet with Likert scales 1-5 representing higher probabilities of presence of urinary malignancies for larger number). The diagnostic values of split-bolus and single-bolus CTU will analyzed using reference standards by final diagnoses of urinary malignancies (i.e.: presence of urinary malignancies based on histological examinations of cytology examinations, biopsies or surgical specimens). The diagnostic performance of split-bolus CTU and single- bolus CTU for urinary malignancies will be compared using areas under receiver operating curve (ROC) to determine whether there is presence of significant difference .

This study will enroll 352 patients. The calculation of sample size is according to the following equation:

n2=〖(Z∝+Zβ/2)〗^2/〖(δ-|ε|)〗^2 [p1(1-p1)/k+p1(1-p2)]

∝=0.05, β=0.2, δ=0.05, p1=0.96, p2=0.80 Then, the number of each arm patient should be ≥ 141 patients. However, if 20 % of the enrolled patients by fitting inclusion criteria are excluded by fitting exclusion criteria, the number of each arem should be ≥ 176 patients. Thus, this study plans to enroll 352 patients (for two arms). The enrolled patients are randomized to two groups (using single-bolus CTU versus using split-bolus CTU) using permuted block method.

Inclusion Criteria: Fitting all of the followings

1. age ≥ 40 years old
2. presenting with gross hematuria or having a history of urothelial carcinomas
3. normal renal function (i.e.: estimated glomerular filtration rate ≧ 60 mL/min/1.73 m2)
4. no allergy history of iodinated contrast medium

Exclusion Criteria: Fitting any of the followings

1. pregnant or lactating woman
2. withdrawal of informed consent

Plan to make individual participant data