Abstract：
BACKGROUND: Apparent diffusion coefficient (ADC) value is an important part of bladder cancer magnetic resonance imaging (MRI) assessment and can predict the aggressive and invasive potentials. There is growing interest in whole tumor volume measurements.
OBJECTIVE: To investigate if the volumetric ADC measurement method will significantly exceed the diagnostic performance of the selected region of interest (ROI) method in everyday practice.
METHODS: A prospective evaluation was carried out of 50 patients with bladder cancer by two radiologists. The mean and the minimum ADC values were measured using both methods. The inter-reader agreement was determined by the intraclass correlation coefficient. The ADC values were compared between different grades, states of muscle invasion, and lympho-vascular invasion (LVI); then, validity was evaluated using receiver operating characteristic (ROC) curves. Areas under the curve (AUC) were then compared for the level of statistical significance.
RESULTS: The inter-observer agreement was excellent for the ADC values using both methods. The volumetric measurement provides higher mean and lower minimum ADC values with statistically significant differences (P <0.00001). The highest diagnostic accuracy for differentiating tumor grade and predicting muscle invasion was for the minimum ADC by a selected ROI. However, the differences between the achieved AUCs were of no statistical significance. None of the ADC values predicted LVI with statistical significance.
CONCLUSIONS: The selected ROI and volumetric measurement methods of mean and minimum ADC in bladder cancer yield different values, still having comparable diagnostic performance with accurate ROI sampling. The minimum ADC value by ROI is preferred in everyday clinical practice.
OBJECTIVE: To investigate if the volumetric ADC measurement method will significantly exceed the diagnostic performance of the selected region of interest (ROI) method in everyday practice.
METHODS: A prospective evaluation was carried out of 50 patients with bladder cancer by two radiologists. The mean and the minimum ADC values were measured using both methods. The inter-reader agreement was determined by the intraclass correlation coefficient. The ADC values were compared between different grades, states of muscle invasion, and lympho-vascular invasion (LVI); then, validity was evaluated using receiver operating characteristic (ROC) curves. Areas under the curve (AUC) were then compared for the level of statistical significance.
RESULTS: The inter-observer agreement was excellent for the ADC values using both methods. The volumetric measurement provides higher mean and lower minimum ADC values with statistically significant differences (P <0.00001). The highest diagnostic accuracy for differentiating tumor grade and predicting muscle invasion was for the minimum ADC by a selected ROI. However, the differences between the achieved AUCs were of no statistical significance. None of the ADC values predicted LVI with statistical significance.
CONCLUSIONS: The selected ROI and volumetric measurement methods of mean and minimum ADC in bladder cancer yield different values, still having comparable diagnostic performance with accurate ROI sampling. The minimum ADC value by ROI is preferred in everyday clinical practice.
摘要：
背景：表观扩散系数（ADC）值是膀胱癌磁共振成像（MRI）评估的重要组成部分，可以预测侵袭性和侵入性潜力。对整个肿瘤体积的测量越来越感兴趣。
目的：研究体积ADC测量方法在日常实践中是否会明显超过所选感兴趣区域（ROI）方法的诊断性能。
方法：由两名放射科医生对50例膀胱癌患者进行了前瞻性评估。使用两种方法测量平均和最小ADC值。读者之间的一致性由类内相关系数确定。比较不同等级之间的ADC值，肌肉入侵的状态，和淋巴血管浸润（LVI）；然后，使用受试者工作特征(ROC)曲线评估有效性。然后比较曲线下面积(AUC)的统计学显著性水平。
结果：对于使用两种方法的ADC值，观察者之间的一致性非常好。体积测量提供较高的平均ADC值和较低的最小ADC值,具有统计学显著差异(P<0.00001)。区分肿瘤等级和预测肌肉侵袭的最高诊断准确性是通过选定的ROI获得最小的ADC。然而,所达到的AUC之间的差异无统计学意义.没有一个ADC值预测LVI具有统计学意义。
结论：选择的ROI和体积测量方法在膀胱癌中的平均和最小ADC产生不同的值，仍然具有与准确的ROI采样相当的诊断性能。ROI的最小ADC值在日常临床实践中是优选的。
目的：研究体积ADC测量方法在日常实践中是否会明显超过所选感兴趣区域（ROI）方法的诊断性能。
方法：由两名放射科医生对50例膀胱癌患者进行了前瞻性评估。使用两种方法测量平均和最小ADC值。读者之间的一致性由类内相关系数确定。比较不同等级之间的ADC值，肌肉入侵的状态，和淋巴血管浸润（LVI）；然后，使用受试者工作特征(ROC)曲线评估有效性。然后比较曲线下面积(AUC)的统计学显著性水平。
结果：对于使用两种方法的ADC值，观察者之间的一致性非常好。体积测量提供较高的平均ADC值和较低的最小ADC值,具有统计学显著差异(P<0.00001)。区分肿瘤等级和预测肌肉侵袭的最高诊断准确性是通过选定的ROI获得最小的ADC。然而,所达到的AUC之间的差异无统计学意义.没有一个ADC值预测LVI具有统计学意义。
结论：选择的ROI和体积测量方法在膀胱癌中的平均和最小ADC产生不同的值，仍然具有与准确的ROI采样相当的诊断性能。ROI的最小ADC值在日常临床实践中是优选的。
