The Application Of High B-value Diffusion-weighted Imaging And Perfusion Parameter In Diagnosis Of Transition Zone Cancer

Part I : Diagnostic Value of Diffusion-weighted Imaging and Apparent Diffusion Coefficient Value in Transition Zone CancerPurpose: To investigate the diagnostic performance of 3.0-T diffusion-weighted imaging(DWI) and apparent diffusion coefficient (ADC) values for detection of transition zone(TZ) cancer by using b values of 1000, 2000, and 3000s/mm2.Materials and Methods: Our Institutional Review Board approved this prospective study.Patients underwent 3.0T prostate MRI examination including T2WI, T1WI and DWI with b-values of 1000, 2000, and 3000s/mm2. The following three sets of images were evaluated by two radiologists in consensus: protocol A (T2WI and DWI with b value of 1000s/mm2), protocol B (T2WI and DWI with b value of 2000s/mm2), and protocol C(T2WI and DWI with b value of 3000s/mm2). The likelihood of tumor was record and ADC values were measured for suspicious lesions on three sets of ADC maps (b = 0,1000s/mm2, 0, 2000s/mm2, and 0, 3000s/mm2, respectively). The independent t test and Mann-Whitney U test were used to compare the ADC value between TZ cancer and benign prostate tissue. For estimation of diagnostic capability,area under the receiver operating characteristic (ROC) curve was calculated.Results: 49 patients were recruited in our study. All patients underwent ultrasound guided prostate biopsy after MRI examination. 25 were histopathologically confirmed with TZ cancer and 24 with benign prostate tissue. The areas under the curves (AUC) in protocol C was significantly higher than those in protocol A and in protocol B (p = 0.0029 and 0.0492).The ADC value of TZ cancer was significantly lower than that of benign prostate tissue (p = 0.002, p < 0.001, and p < 0.001). The AUC of ADC value (b = 1000s/mm2),ADC value (b = 2000s/mm2) and ADC value (b = 3000s/mm2) were 0.718, 0.839 and 0.887, respectively. There was no statistical significance between the differences of ADC value (b = 2000s/mm2) and ADC value (b = 3000s/mm2),p = 0.308.Conclusion: DWI (b = 3000s/mm2) can improve the diagnostic accuracy for diagnosis of TZ cancer. For quantitative analysis, ADC value (b = 2000s/mm2) and ADC value (b =3000s/mm2) were diagnostically superior to ADC value (b = 1000s/mm2) for diagnosis of TZ cancer.Part ? : Incremental Values of Apparent Diffusion Coefficient in High b-Value Diffusion Weighted Imaging to PI-RADS v2 for Diagnosis of Transition Zone CancerPurpose: To evaluate the incremental value of the apparent diffusion coefficient (ADC) to the Prostate Imaging Reporting and Data System version 2 (PI-RADS v2) reporting system for diagnosis of transition zone (TZ) cancer.Materials and Methods: Our Institutional Review Board approved this prospective study.Patients underwent 3.0T prostate MRI examination. Two radiologists independently analyzed the images of suspicious lesions detected on MRI and assigned a PI-RADS v2 score according to PI-RADS v2 guidelines. The ADC values of suspicious lesions were also measured. Biopsy specimens were used as the reference standard. Interobserver agreement was evaluated using the kappa coefficient or intra-class correlation coefficient(ICC). Binary logistic regression and receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic performance.Results: 49 patients were recruited in our study. 25 were histopathologically confirmed with TZ cancer and 24 with benign prostate tissue. The interobserver agreement between the two radiologists was good for the PI-RADS v2 scores (? = 0.753) and excellent for the ADC values (ICC = 0.973). The combination of the ADC value and the PI-RADS v2 score yielded a significantly higher area under the curve (AUC) than achieved with the PI-RADS v2 score alone (Reader A: 0.861 vs 0.748, p = 0.0475; Reader B: 0.863 vs 0.723, p =0.0224, respectively).Conclusion: The addition of the ADC value to the PI-RADS v2 score significantly improved the diagnostic accuracy for diagnosis of TZ cancer.Part ?: Incremental Values of Perfusion Parameters to Apparent Diffusion Coefficient Value for Diagnosis of Transition Zone CancerPurpose: To investigate the incremental value of perfusion parameters to the apparent diffusion coefficient (ADC) value for diagnosis of transition zone (TZ) cancer.Materials and Methods: Our Institutional Review Board approved this prospective study.Patients underwent 3.0T prostate MRI examination. Two radiologists analyzed the images of suspicious lesions detected on MRI in consensus and measured the ADC value, Ktrans,Kep and Ve of suspicious lesions. Biopsy specimens were used as the reference standard.The Mann-Whitney U test was used to compare the differences between TZ cancer and benign prostate tissue. Binary logistic regression and receiver operating characteristic(ROC) analysis was performed to evaluate the diagnostic performance.Results: 49 patients were recruited in our study. 25 were histopathologically confirmed with TZ cancer and 24 with benign prostate tissue. The ADC value and Kep differed significantly between TZ cancer and benign prostate tissue (p = 0.085, p = 0.610). The difference of Ktrans and Ve between TZ cancer was not significant (p = 0.085, p = 0.610).No individual perfusion parameter improved the area under the curve (AUC) of ADC value (p = 0.858, 0.699, 0.709).Conclusion: The addition of the perfusion parameters to the ADC value cannot improve the diagnostic accuracy for diagnosis of TZ cancer.