Characterization of upper urinary tract urothelial lesions in patients with gross hematuria using diffusion-weighted MRI: A prospective study

ObjectiveOur objective was to evaluate the utility of diffusion-weighted MRI (DWI) and apparent diffusion coefficient (ADC) values in differentiation between malignant and non malignant lesions of the upper urinary tract in patients with gross hematuria.MethodsWe prospectively evaluated 51 patients with gross hematuria. The MRI sequences included T1, T2 weighted spin echo imaging and DWI with calculating ADC values of each detected lesion. Two radiologists independently reviewed the imaging sequences. The reference standard was established on the basis of histopathology. The agreement between two reviewers was tested by K statistics. Group comparison was completed with the Kruskal–Wallis test for ADC values and the Mann–Whitney U test. Furthermore, the diagnostic performance was evaluated by using the area under the curve (AUC) of receiver operating characteristic (ROC) curve analysis.ResultsDWI had higher sensitivity and specificity for both reviewers reviewer 1 [94%, 77%] and reviewer 2 [89% and 77%] over conventional sequences [T1 and T2] reviewer 1 [86%, 77%] and reviewer 2 [84% and 69%], respectively. Interobserver agreement was good (K = 0.79) using DWI.AUC was 89% and ROC curve revealed that a value of 1.5 × 10−3 mm2/s is the most significant cut off value with highest sensitivity and specificity 79% and 82% respectively in differentiation between malignant and non malignant lesions.ConclusionDWI had high sensitivity and accuracy in detection of upper urinary tract urothelial lesions and could also be used in differentiation between malignant and non malignant lesions of upper urinary tract lesions in patients with gross hematuria.Advances in knowledgeTo our knowledge this is the first prospective study that included benign lesions and tried to differentiate between malignant and non malignant lesions of the upper urinary tract.