Background The histological grade of bladder cancer (BCa) is an important factor associated with the treatment and prognosis. However, accurate determination of the preoperative histological grade of BCa remains a challenge. Purpose To investigate the diagnostic potential of synthetic MRI (SyMRI) in evaluating the histological grade of BCa. Study Type Prospective. Subjects Sixty patients (48 men and 12 women; mean age, 65 ± 11 years) with pathologically confirmed BCa (33 with high‐grade BCa and 27 with low‐grade BCa) were enrolled. Field Strength/Sequence Diffusion‐weighted imaging (DWI) acquired by a single‐shot echo‐planar sequence and SyMRI acquired by a multidynamic multiecho (MDME) sequence at 3.0 T. Assessment Preoperative quantitative longitudinal relaxation time (T1), transverse relaxation time (T2), proton density (PD), and apparent diffusion coefficient (ADC) values of BCa were independently measured by two radiologists. Statistical Tests Interclass correlation coefficient (ICC), independent sample t‐test, Mann–Whitney U test, Delong test, and receiver operating characteristic curve (ROC) analysis were used. Results Significant differences were found in the mean of all the T1, T2, PD, and ADC values between high‐ and low‐grade BCa. The best diagnostic performance was found for the mean ADC value with an area under the ROC curve (AUC) of 0.869, while the AUC values of the mean PD, T1, and T2 values were 0.755, 0.740, and 0.723, respectively. Data Conclusion SyMRI may be a potential noninvasive technique for evaluating the histological grade of BCa. However, the overall diagnostic performance of SyMRI‐derived parameters was inferior to the ADC value. Levels of Evidence 2. Technical Efficacy Stage 2.

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Background Synthetic magnetic resonance imaging (MRI) can provide quantitative information about inherent tissue properties and synthesize tailored contrast-weighted images simultaneously in a single scan. This study aimed to investigate the clinical feasibility of synthetic MRI in bladder tumors. Methods A total of 47 patients (37 males; mean age: 66±10 years old) with postoperative pathology-confirmed papillary urothelial neoplasms of the bladder were enrolled in this retrospective study. A 2-dimensional (2D) multi-dynamic multi-echo pulse sequence was performed for synthetic MRI at 3T. The overall image quality, lesion conspicuity, contrast resolution, resolution of subtle anatomic structures, motion artifact, blurring, and graininess of images were subjectively evaluated by 2 radiologists independently using a 5-point Likert scale for qualitative analysis. The signal intensity ratio (SIR), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were measured for quantitative analysis. Linear weighted Kappa, Wilcoxon’s signed-rank test, and the Mann–Whitney U-test were used for statistical analysis. Results The interobserver consistency was excellent (κ values: 0.607–1). Synthetic T1-weighted (syn-T1w) and synthetic T2-weighted (syn-T2w) images obtained scores of 4 in most subjective terms, which were relatively smaller than those of conventional images. The SIR and SNR of syn-T1w were significantly higher than those of con-T1w images (SIR 2.37±0.86 vs. 1.47±0.20, P<0.001; SNR 21.83±9.43 vs. 14.81±3.30, P<0.001). No difference was found in SIR between syn-T2w and conventional T2-weighted (con-T2w) images, whereas the SNR of the syn-T2w was significantly lower (8.79±4.06 vs. 26.49±6.80, P<0.001). Additionally, the CNR of synthetic images was significantly lower than that of conventional images (T1w 1.41±0.72 vs. 2.68±1.04; T2w 1.40±0.87 vs. 4.03±1.55, all P<0.001). Conclusions Synthetic MRI generates morphologic magnetic resonance (MR) images with diagnostically acceptable image quality in bladder tumors, especially T1-weighted images with high image contrast of tumors relative to urine. Further technological improvements are needed for synthetic MRI to reduce noise. Combined with T1, T2, and proton density (PD) quantitative data, synthetic MRI has potential for clinical application in bladder tumors.