Urinary bladder cancer is the second most common neoplasm of the urinary tract worldwide. It accounts for 6-8% of malignancy in men and 2- 3% in women, with the highest incidence rates in North America , Europe and areas with endemic schistosomiasis in Africa and the Middle East.(1) Factors contribute to the development of bladder cancer are: advanced age, male sex, cigarette smoking and parasitic infection with schistosomiasis.~Bladder cancer ranges from unaggressive non-invasive tumor that recur and commit patients to long life surveillance to aggressive and invasive tumors with high disease mortality.(2) Knowledge of the clinical, histopathologic, and imaging features of common bladder neoplasms is essential. The first-line imaging tool for assessing bladder lesions is ultrasonography, which may be followed by a cross-sectional imaging examination such as computed tomography or magnetic resonance imaging if the origin of the mass is unclear or if distant spread is suspected.Computed tomography(CT) is of limited use because of :harm of ionizing radiation ,poor precision and high interobserver variability in the staging of bladder cancer.(3) Accurate preoperative diagnosis of detrusor muscle invasion of bladder cancer is important because non-muscle-invasive (stage T1 or lower) and muscle-invasive (stage T2 or higher) bladder cancers are treated differently.Prognosis of the tumor depends mainly on grade ,depths of invasion and the presence of carcinoma insitu(CIS).(4) MRI has now become established as the modality of choice for the local staging of bladder cancer and assessment of regional lymph node involvement and the tumor spread to pelvic bones and upper urinary ttract.(5) As it has high tissue contrast, multiplanar imaging capabilities, and the ability of tissue characterization.(6) Currently, the multi-parametric magnetic resonance imaging (mp-MRI) is widely used for bladder cancer diagnosis and staging. It consists of the conventional sequence [T2-weighted anatomic imaging (T2WI)] and functional MRI techniques [dynamic contrast-enhanced (DCE) imaging and diffusion-weighted imaging (DWI)] .(7) Multiparametric MRI improve patient care through imaging of the bladder with better resolution of the tissue planes than computed tomography and without radiation exposure.(8) Diagnostic accuracy of multiparametric MRI in differentiation between muscle invasive and non muscle invasive bladder cancer was 84% with highest sensitivity 78%.(9) The Vesical Imaging-Reporting and Data System (VIRADS) scoring system was created in 2018 to standardise imaging and reporting of bladder cancer staging with multiparametric MRI which suggests the likelihood of detruser muscle invasion. Muscle invasion disease carries a worse prognosis and requires radical surgery.(4) Multiparametric MRI and VI-RADS have been validated as appropriate tools for local staging of bladder cancer.(10) VI-RADS provides high diagnostic accuracy to diagnose high grade and muscle invasive bladder cancer.(11) Data collection :Prospectively calculated and collected data will be analysed. Computer software: SPSS package 23 Statistical tests: Descriptive statistics will be performed with frequency and cross tabulations for categorical variables. Means and standard deviations will be measured for numerical variables. The chi-square test will be used for comparing independent categorical variables. Monte Carlo simulations will be run for multiple groups if comparisons will not meet the chi-square criteria; Fishers exact test will be used in the comparison of the groups. Students t-test will be used for comparing the numerical data displaying normal distribution; the MannWhitney U-test will be performed for the numerical variables not displaying normal distribution. The P-value will be set at 0.05 and all of the comparisons will be two-tailed.
The purpose of this study is to assess the performance of multiparametric MRI in detection of occult muscle invasion in urinary bladder cancer