ABSTRACT
Objective To explore the application value of histogram quantitative analysis based on diffusion kurtosis imaging (DKI) in detecting prostate cancer (PCa) and assessing tumor aggressiveness. Methods One hundred and twenty patients were retrospectively enrolled in Zhongnan Hospital of Wuhan University from November 2014 to November 2016,with diagnosis confirmed by prostate biopsy,definitive Gleason score(GS) results and prostate MRI examinations. There were 90 tumor foci in 67 prostate cancer patients, including 23 cases with GS≤6 (37 tumor foci), 7 GS 3+4=7(7 tumor foci), 3 GS 4+3=7(3 tumor foci).Thirty four cases who were with GS≥8(43 tumor foci)were divided into low-grade PCa(37 GS≤6)and high-grade PCa(53 GS≥7).Fifty three patients were diagnosed with benign prostatic hyperplasia(BPH).All patients underwent conventional prostate MRI examination and multi b value DKI examination. The apparent diffusion coefficient(Dapp)corrected by non-Gaussian model,apparent kurtosis coefficient(Kapp)and ADC value were obtained for histogram analysis.Student's t test was executed to compare the differences of ADCs,Dappand Kappvalues between prostate cancer(PCa)and BPH,low-grade PCa and high-grade PCa.ROC curves were used to evaluate the diagnostic value of ADCs,Dappand Kappvalues in differentiating PCa from BPH and differentiating high-grade PCa from low-grade PCa. Pearson correlation was used to assess the correlations between the histogram quantitative parameters of ADCs,Dappand Kappvalues and Gleason score. Results Except skew of Kapp, the other histogram quantitative parameters of Kappbetween PCa and BPH were statistically significant (all P<0.05). Except the skew of Kapp, the other histogram quantitative parameters of Kappbetween low-grade PCa and high-grade PCa were statistically significant(all P<0.05).The median,mean and standard deviation of ADC,Dappand Kapphave good diagnostic value in detecting PCa from BPH and differing high-grade PCa from low-grade PCa.The area under ROC curve was ranging from 0.558 to 0.985.There were moderate to high correlations between median,mean of ADC(r=-0.701 and-0.676, respectively),median,mean of Dapp(r=-0.712 and-0.701,respectively),median,standard deviation,and kurtosis of Kapp(r=0.458,0.516 and-0.528,respectively)and Gleason score(all P<0.05).Conclusion The DKI parameters combined with histogram quantitative analysis is helpful in detecting prostate cancer and assessing tumor aggressiveness.