Clinical Value Of High-resolution Magnetic Resonance Imaging In Preoperative Staging Of Urinary Bladder Cancer

Part 1 Diffusion-weighted magnetic resonance imaging in bladder cancer:comparison of readout-segmented EPI and single-shot EPI TechniquesObjective: To evaluate whether readout-segmented echo planar imaging(RS-EPI)can provide better image quality in imaging bladder cancer in comparison with single-shot echo planar imaging(SS-EPI),and to compare quantitative image parameters derived from RS-EPI with those of SS-EPI.Materials and Methods: Thirty-five patients with bladder cancer were enrolled in this prospective study,which was approved by the local institutional review board and written informed consent was obtained from each patient.In all patients,the examination protocols of bladder cancer included RS-EPI and SS-EPI techniques was performed on a3 T MR system.RS-EPI and SS-EPI DWI images were evaluated by two independent observers for identification of susceptibility,detectability,motion artifacts and image blurring of the lesions.Signal-to-noise ratio(SNR),contrast-to-noise ratio(CNR),signal intensity ratio(SIR)and ADC values of bladder lesions were measured and compared.Inter-observer agreement was assessed with the Kappa statistics,the differences of scores of RS-EPI and SS-EPI and quantitative parameters were assessed by using paired sample t text and Wilcoxon signed rank tests.Results: There was good reader agreement in the scores,the Kappa values were0.878,0.860,0.748,0.842.There were significant differences in susceptibility,detectability and image blurring(all p < 0.05),except for motion artifacts of bladder lesions(p > 0.05).RS-EPI technique is superior to SS-EPI technique in image quality.No significant difference was observed for SNR and ADC values of bladder lesions between SS-EPI and RS-EPI techniques(96.65±51.59 vs.85.79±43.41,p=0.085 and1239.09±253.73×10-6 mm2/s vs 1230.16±239.60×10-6 mm2/s,p=0.627,respectively).There were significant differences in CNR and SIR values of the lesions between both techniques(3.54±1.26 vs.3.91±1.21,p=0.024 and 5.03±1.26 vs.5.51±1.35,p=0.015,respectively).Conclusion: RS-EPI technique has significantly higher image quality and better image contrast in bladder DWI than SS-EPI technique,in addition no significant difference in SNR and ADC values,which showed that RS-EPI was a promising method for reducing image artifacts and improving image quality in bladder cancer.The image blurring and lesion detectability of bladder cancer was significantly improved with RS-EPI.The RS-EPItechnique provided significant image quality improvement compared with SS-EPI at 3.0 T and could potentially provide better image quality in patients with bladder cancer.Part 2 Clinical value of MR high-resolution T2-Weighted imaging plus readout-segmented echo-planar imaging in preoperative diagnosis muscle and non-muscle invasive bladder cancerObjective: To evaluate the clinical value of high resolution T2-Weighted imaging(HR-T2WI),readout-segmented echo-planar imaging(RS-EPI)and HR-T2 WI plus RS-EPI in differentiating non-muscle invasive bladder cancer(NMIBC)and muscle invasive bladder cancer(MIBC).Methods: In a preoperative way,there were ninety-five patients with confirmed bladder cancer by cystoscope biopsy who underwent the operation and could have the pathological staging.In all patients,the examination protocols of bladder cancer included HR-T2 WI and RS-EPI techniques was performed on a 3.0T MRI.Two radiologists interpreted three image sets including HR-T2 WI,RS-EPI and HR-T2WI+RS-EPI to differentiate NMIBC and MIBC.ROC curves for each diagnostic method were obtained,and the corresponding AUCs were calculated.De Long test was used to compare the three methods.Results: Three diagnostic modalities were all effectively used to differentiate NMIBC and MIBC.The sensitivity,specificity,accuracy and AUC of HR-T2 WI were 95.5%,83.4%,88.5% and 0.889;The sensitivity,specificity,accuracy and AUC of RS-EPI were84.1%,94.1%,89.5% and 0.891;The sensitivity,specificity,accuracy and AUC of HR-T2 WI plus RS-EPI were 93.1%,100%,96.8%.and 0.966.HR-T2 WI plus RS-EPI has better diagnostic efficiency in preoperative diagnosis muscle and non-muscle invasive bladder cancer than the method in only HR-T2 WI or RS-EPI.Conclusion: HR-T2 WI plus RS-EPI can be used as an examination method for preoperative diagnosis of the muscle and non-muscle invasive bladder cancer.