Application Of New Functional Magnetic Resonance Imaging And The PI-RADS Guidelines In Prostate Cancer

Part ? Feasibility study of FA and ADC values by diffusion tensor imaging: differentiate and classify abnormal signal nodules in prostate transition zoneObjective: To investigate the diagnostic utility of FA?fractional anisotropy?and ADC?apparent diffusion coefficient?values of diffusion tensor imaging?DTI?in differentiating and classifying abnormal signal nodules in prostate transition zone?TZ?.Materials and Methods: Fifty-four transition zone-prostate cancer?TZ-PCa?cases and thirty benign prostatic hyperplasia?BPH?cases with pathologically confirmed were enrolled in this retrospective study.All the patients who underwent with 3.0T MRI were divided into 3 groups: BPH,Gleason score?GS??3+4=7 and GS?4+3=7.The FA and ADC values of the region of interest?ROI?were respectively measured,using one-way ANOVA to compare the difference between groups and Dunnett T3 test to compare between groups.Results: The mean FA values of the 3 groups were 150.52±29.63,215.21±54.59 and 251.01±59.47 respectively,and there was statistical difference between the groups?F=32.882,P = 0.000?;comparison among groups: just BPH with the other two groups had statistical difference?P = 0.000,P = 0.000?.The mean ADC values(×10^-6mm²/s)of the 3 groups were 1606.11±234.64,854.00±172.29 and 742.78±115.91 respectively,and there was statistical difference between the groups?F=202.928,P = 0.000?;comparison among groups: BPH with the other two groups had statistical difference?P = 0.000,P = 0.000?;and groups between the GS?3+4=7 and GS?4+3=7 also had statistical difference?P = 0.040?.Conclusions: The FA and ADC values of DTI have higher value for distinguishing between benign and malignant nodules;however,ADC values have more obvious advantages than FA in the further classification.Part ? Validation of SE-EPI-based T2 mapping for characterization of prostate cancer: a new method compared with the traditional CPMG methodObjective: We aim to compare the results of spin echo-echo planar imaging?SE-EPI?-based T2 mapping?a new quantitative analysis combining T2 values at different b-values and apparent diffusion coefficient?ADC?values at different echo times?TEs??with those of the conventional Carr-Purcell-Meiboom-Gill?CPMG?method and to investigate the potential validity of SE-EPI-T2 mapping for the characterization of prostate cancer?PCa?.Materials and Methods: Our retrospective study finally included 42 PCa patients?the cancer group?with 135 lesions and 42 noncancer patients?the noncancer group?with 120 lesions?from 1/2016 to 11/2016?who underwent 3.0T MRI by 8 independent acquisitions with b-values ranging from 0 to 2000 s/mm2 and TEs ranging from 32 to 100 ms before a 12-core transrectal ultrasound?TRUS?-guided prostate biopsy.One radiologist with four years of experience in prostate images used in-house developed software to draw regions of interest?ROIs?for each patient.The Mann-Whitney U test and two-sample t-tests were used to analyze differences between the cancerous and noncancerous groups.The correlations between CPMG-T2 values and SE-EPI-T2 values at different b-values were determined by Spearman's rho analysis or Pearson analysis.Bland-Altman analysis was used to compare the agreement between the two methods.Results: Substantial agreement regarding the measurements was observed between the two methods.The average correlation between the CPMG-T2 values and SE-EPI-T2 values was moderate and positive?except for b=1000 and 2000 s/mm²,which yielded no statistically significant differences?,and the best correlations were found at b=100 s/mm² in the noncancer group?r= 0.603,P = 0.000?and at b=0 and 100 s/mm² in the cancer group?r= 0.513,P = 0.000;r= 0.508,P = 0.000?.In addition,statistically significant differences were found between the noncancer and cancer groups in T2 values?all b-values,except for b=2000 s/mm²,P = 0.526?and ADC values?diff TEs??P = 0.000?.Conclusions: Substantial agreement in the measurements was found between the SE-EPI method and CPMG method.SE-EPI-based T2 mapping has potential clinical value for the prostate and can be easily used in multiparametric quantitative analyses with T2 and ADC values.SE-EPI-based T2 mapping can be considered an alternative to the traditional CPMG-T2 mapping method.Part ? Diagnostic performance and interobserver consistency of the Prostate Imaging Reporting and Data System Version 2: a Study on six prostate radiologists with different experiences from half a year to 17 yearsObjective: One of the main aims of the updated Prostate Imaging Reporting and Data System Version 2?PI-RADS v2?is to diminish variation in the interpretation and reporting of prostate imaging,especially among readers with varied experience levels.This study aimed to retrospectively analyze diagnostic consistency and accuracy for prostate disease among six radiologists with different experience levels from a single center and to evaluate the diagnostic performance of PI-RADS v2 scores in the detection of clinically significant prostate cancer?PCa?.Materials and Methods: From December 2014 to March 2016,84 PCa patients and 99 benign prostatic hyperplasia patients who underwent 3.0T multiparametric magnetic resonance imaging before biopsy were included in our study.All patients received evaluation according to the PI-RADS v2 scale?1-5 scores?from six blinded readers?with 6 months and 2,3,4,5,or 17 years of experience,respectively,the last reader was a reviewer/contributor for the PI-RADS v2?.The correlation among the readers' scores and the Gleason score?GS?was determined with the Kendall test.Intra-/inter-observer agreement was evaluated using ? statistics,while receiver operating characteristic curve and area under the curve analyses were performed to evaluate the diagnostic performance of the scores.Results: Based on the PI-RADS v2,the median ? score and standard error among all possible pairs of readers were 0.506 and 0.043,respectively;the average correlation between the six readers' scores and the GS was positive,exhibiting weak-to-moderate strength?r= 0.391,P = 0.006?.The AUC values of the six radiologists were 0.883,0.924,0.927,0.932,0.929,and 0.947,respectively.Conclusions: The inter-reader agreement for the PI-RADS v2 among the six readers with different experience is weak to moderate.Different experience levels affect the interpretation of MRI images.