[Value of whole-lesion apparent diffusion coefficient histogram parameters in preoperative differentiation of histological grade of bladder urothelial carcinoma].

<b>Objective:</b> To explore the clinical value of histogram parameters of the whole-leison apparent diffusion coefficient (ADC) in the histological grade of bladder urothelial carcinoma before operation. <b>Methods:</b> A retrospective analysis was conducted on patients with pathologically-proven bladder urothelial carcinoma who underwent preoperative bladder MRI at the First Medical Center of Chinese PLA General Hospital between January 1, 2019 and July 30, 2022. The patients were divided into high-grade and low-grade groups based on the histological grading of bladder urothelial carcinoma. The ADC histogram parameters of the two groups were compared. Multivariate logistic regression analyses were used to identify associated factors of high-grade bladder urothelial carcinoma. The diagnostic performance of the histogram parameters for the histological grade of bladder urothelial carcinoma was analyzed using receiver operating characteristic (ROC) curves. <b>Results:</b> A total of 63 patients were included, aged [<i>M</i> (<i>Q</i>₁, <i>Q</i>₃), 64 (42, 84)] years and comprising 52 males (82.5%). Among them, 30 patients (47.6%) were classified into the low-grade group, and 33 patients (52.4%) into the high-grade group. Differences were observed between the two groups in tumor volume, ADC_mean, ADC_1%, ADC_5%, ADC_10%, ADC_25%, ADC_50%, ADC_75%, ADC_90%, ADC_95%, ADC_99%, variance, kurtosis and skewness (all <i>P</i><0.05). ADC_mean (<i>OR</i>=1.042, 95%<i>CI</i>: 1.004-1.082), ADC_10% (<i>OR</i>=0.975, 95%<i>CI</i>: 0.950-0.999) and ADC_75% (<i>OR</i>=0.979, 95%<i>CI</i>: 0.962-0.997) were associated with high-grade bladder urothelial carcinoma. The area under the curve (AUC) of ADC_mean, ADC_10% and ADC_75% for differentiating the histological grade of bladder urothelial carcinoma before surgery were 0.772 (95%<i>CI</i>: 0.649-0.868), 0.690 (95%<i>CI</i>: 0.561-0.800) and 0.816 (95%<i>CI</i>: 0.698-0.902), respectively. The combined model of these 3 parameters demonstrated an AUC of 0.853 (95%<i>CI</i>: 0.741-0.929), with a sensitivity of 78.8% and a specificity of 83.3%. The diagnostic performance of the combined model was superior to that of ADC_10% alone (<i>P</i>=0.017), but no statistically significant differences were observed compared to ADC_mean and ADC_75% (both <i>P</i>>0.05). <b>Conclusions:</b> Whole-lesion ADC histogram parameters, including ADC_mean, ADC_10%, ADC_75% and the combined model of these 3 parameters could be utilized for the histological grade of bladder urothelial carcinoma before operation, with high sensitivity and specificity.