Prostate Cancer Detection with Multiparametric Magnetic Resonance Imaging： Prostate Imaging Reporting and Data System Version 1 versus Version 2

Background：Prostate Imaging Reporting and Data System （PI-RADS） is a globally acceptable standardization for multiparametric magnetic resonance imaging （mp-MRI） in prostate cancer （PCa） diagnosis.The American College of Radiology revised the PI-RADS to address the limitations of version 1 in December 2014.This study aimed to determine whether the PI-RADS version 2 （PI-RADS v2） scoring system improves the diagnostic accuracy of mp-MRI of the prostate compared with PI-RADS v1.Methods：This retrospective study was approved by the institutional review board.A total of 401 consecutive patients,with clinically suspicious Pca undergoing 3.0 T mp-MRI （T2-weighted imaging ＋ diffusion-weighted imaging ＋ DCE） before transrectal ultrasound-guided biopsy between June 2013 and July 2015,were included in the study.All patients were scored using the 5-point PI-RADS scoring system based on either PI-RADS v1 or v2.Receiver operating characteristics were calculated for statistical analysis.Sensitivity,specificity,and diagnostic accuracy were compared using McNemar＇s test.Results：Pca was present in 150 of 401 （37.41%） patients.When we pooled data from both peripheral zone （PZ） and transition zone （TZ）,the areas under the curve were 0.889 for PI-RADS v1 and 0.942 for v2 （P =0.0001）.Maximal accuracy was achieved with a score threshold of 4.At this threshold,in the PZ,similar sensitivity,specificity,and accuracy were achieved with v 1 and v2 （all P 〉 0.05）.In the TZ,sensitivity was higher for v2 than for v1 （96.36% vs.76.36%,P =0.003）,specificity was similar for v2 and v1 （90.24% vs.84.15%,P =0.227）,and accuracy was higher for v2 than for v1 （92.70% vs.81.02%,P =0.002）.Conclusions：Both v1 and v2 showed good diagnostic performance for the detection of Pca.However,in the TZ,the performance was better with v2 than with v1.

Using the Prostate Imaging Reporting and Data System version 2 （PI-RIDS v2） to detect prostate cancer can prevent unnecessary biopsies and invasive treatment

Prostate cancer （PCa） is one of the most common cancers among men globally. The authors aimed to evaluate the ability of the Prostate Imaging Reporting and Data System version 2 （PI-RADS v2） to classify men with PCa, clinically significant PCa （CSPCa）, or no PCa, especially among those with serum total prostate-specific antigen （tPSA） levels in the ＂gray zone＂ （4-10 ng ml-1）. A total of 308 patients （355 lesions） were enrolled in this study. Diagnostic efficiency was determined. Univariate and multivariate analyses, receiver operating characteristic curve analysis, and decision curve analysis were performed to determine and compare the predictors of PCa and CSPCa. The results suggested that PI-RADS v2, tPSA, and prostate-specific antigen density （PSAD） were independent predictors of PCa and CSPCa. A PI-RADS v2 score L≥4 provided high negative predictive values （91.39% for PCa and 95.69% for CSPCa）. A model of PI-RADS combined with PSA and PSAD helped to define a high-risk group （PI-RADS score = 5 and PSAD L≥0 15 ng ml-1 cm-3, with tPSA in the gray zone, or PI-RADS score L≥4 with high tPSA level） with a detection rate of 96.1% for PCa and 93.0% for CSPCa while a low-risk group with a detection rate of 6.1% for PCa and 2.2% for CSPCa. It was concluded that the PI-RADS v2 could be used as a reliable and independent predictor of PCa and CSPCa. The combination of PI-RADS v2 score with PSA and PSAD could be helpful in the prediction and diagnosis of PCa and CSPCa and, thus, may help in preventing unnecessary invasive procedures.

Evaluation of the Prostate Imaging Reporting and Data System for Magnetic Resonance Imaging Diagnosis of Prostate Cancer in Patients with Prostate-specific Antigen 〈20 ng/ml

Background： The European Society of Urogenital Radiology has built the Prostate Imaging Reporting and Data System （PI-RADS） for standardizing the diagnosis of prostate cancer （PCa）. This study evaluated the PI-RADS diagnosis method in patients with prostate-specific antigen （PSA） 〈20 ng/ml. Methods： A total of 133 patients with PSA 〈20 ng/ml were prospectively recruited. T2-weighted （T2WI） and diffusion-weighted （DWI） magnetic resonance images of the prostate were acquired before a 12-core transrectal prostate biopsy. Each patient＇s peripheral zone was divided into six regions on the images; each region corresponded to two of the 12 biopsy cores. T2WI, DWI, and T2W1 ＋ DWI scores were computed according to PI-RADS. The diagnostic accuracy of the PI-RADS score was evaluated using histopathology of prostate biopsies as the reference standard. Results： PCa was histologically diagnosed in 169 （21.2%） regions. Increased PI-RADS score correlated positively with increased cancer detection rate. The cancer detection rate for scores 1 to 5 was 2.8%, 15.0%, 34.6%, 52.6%, and 88.9%, respectively, using T2W1 and 12.0%, 20.2%, 48.0%, 85.7%, and 93.3%, respectively, using DWI. For T2WI ＋ DWI, the cancer detection rate was 1.5% （score 2）, 13.5% （scores 3-4）, 41.3% （scores 5-6）, 75.9% （scores 7-8）, and 92.3% （scores 9-10）. The area under the curve for cancer detection was 0.700 （T2WI）, 0.735 （DWI） and 0.749 （T2WI ＋ DWI）. The sensitivity and specificity were 53.8% and 89.2%, respectively, when The summed score ofT2Wl ＋ DWI

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 Years

Background： 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 pcrformance of PI-RADS v2 scores in the detection of clinically significant prostate cancer （PCa）. Methods： From December 2014 to March 2016, 84 PCa patients and 99 benign prostatic shyperplasia 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. lntra-/inter-observer agreement was evaluated using K 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 k 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. Conclusion： 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.

Dynamic contrast-enhanced magnetic resonance imaging of prostate cancer: A review of current methods and applications

In many areas of oncology, dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI) has proven to be a clinically useful, non-invasive functional imaging technique to quantify tumor vasculature and tumor perfusion characteristics. Tumor angiogenesis is an essential process for tumor growth, proliferation, and metastasis. Malignant lesions demonstrate rapid extravasation of contrast from the intravascular space to the capillary bed due to leaky capillaries associated with tumor neovascularity. DCE-MRI has the potential to provide information regarding blood flow, areas of hypoperfusion, and variations in endothelial permeability and microvessel density to aid treatment selection, enable frequent monitoring during treatment and assess response to targeted therapy following treatment. This review will discuss the current status of DCE-MRI in cancer imaging, with a focus on its use in imaging prostate malignancies as well as weaknesses that limit its widespread clinical use. The latest techniques for quantification of DCE-MRI parameters will be reviewed and compared.

Value of MRI diffusion weighted imaging in localization of prostate cancer with whole-mount step section pathology

Objective To evaluate the value of MRI diffusion weighted imaging in localization of prostate cancer with whole-mount step section pathology. Methods We treated 36 patients using laparoscopic radical prostatectomy from Oct. 2009 to Jun. 2010. Patients who did not have an MRL /DWI examination or a surgical history of pros-

Correlation of High PIRADS Score on Three-Tesla Magnetic Resonance with In-Gantry Magnetic Resonance Guided Biopsy in Patients with Clinical Risk of Prostate Cancer

Introduction and Objective: Prostate cancer detection is a difficult process despite different modalities that are available. The current standard of practice is based on stratifying risk using Prostate Specific Antigen (PSA), digital rectal examination (DRE) and performing a transrectal ultrasound (TRUS) or transperineal (TP) guided biopsy. Recent advances in three-tesla multiparametric magnetic resonance imaging (MP-MRI) technology and the availability of in-gantry MRI guided biopsies (MRGB) have added another diagnostic tool in management of prostate cancer. We review MRGB performed on high Prostate Imaging Reporting and Data System (PIRADS) score lesions in a single centre retrospective study. Materials and Methods: There were 77 patients (mean age 63) with high PIRADS score (4 and 5) that underwent in-gantry MRGB. All the biopsies were performed utilizing dynacad prostate biopsy system on a three-tesla MRI scanner by an urologist with assistance of an experienced radiologist. Two to three samples were obtained from each lesion using an MRI compatible 18-gauge biopsy needle. Three experienced pathologists evaluated the samples and provided the results and Gleason score in each positive sample. Results: Out of the total 77 high PIRADS patients, 54 were PIRADS score 4 (70%) and 23 PIRADS score 5 (30%). There were 22 positive biopsies for adenocarcinoma of prostate with a Gleason score of 3 + 3 = 6 or higher. Out of the 54 PIRADS score 4 lesions, 13 were positive (24%) and out of 23 PIRADS 5 lesions, 9 were positive (39%). The remaining 55 biopsies were negative for prostate cancer. Conclusion: We present our series of MRGB in patients with a high PIRADS score for prostate cancer. While this diagnostic paradigm was in its infancy stages, MRGB was positive in 24% of PIRADS 4 and 39% of PIRADS 5 lesions in this series.

Clinical and prostate multiparametric magnetic resonance imaging findings as predictors of general and clinically significant prostate cancer risk:A retrospective single-center study

Background:To evaluate the predictive values of Prostate Imaging Reporting and Data System version 2(PI-RADS v2),prostate-specific antigen(PSA)level,PSA density(PSAD),digital rectal examination findings,and prostate volume,individually and in combination,for the detection of prostate cancer(Pca)in biopsy-naïve patients.Methods:We retrospectively analyzed 630 patients who underwent transrectal systematic prostate biopsy following prostate multiparametric magnetic resonance imaging.A standard 12-core biopsy procedure was performed.Univariate and multivariate analyses were performed to determine the significant predictors of clinically significant cancer but not Pca.Results:The median age,PSA level,and PSAD were 70 years,8.6 ng/mL,and 0.18 ng/mL/mL,respectively.A total of 374(59.4%)of 630 patients were biopsy-positive for Pca,and 241(64.4%)of 374 were diagnosed with clinically significant Pca(csPCa).The PI-RADS v2 score and PSAD were independent predictors of Pca and csPCa.The PI-RADS v2 score of 5 regardless of the PSAD value,or PI-RADS v2 score of 4 plus a PSAD of<0.3 ng/mL/mL,was associated with the highest csPCa detection rate(36.1%-82.1%).Instead,the PI-RADS v2 score of<3 and PSAD of<0.3 ng/mL/mL yielded the lowest risk of csPCa.Conclusion:The combination of the PI-RADS v2 score and PSAD could prove to be a helpful and reliable diagnostic tool before performing prostate biopsies.Patients with a PI-RADS v2 score of<3 and PSAD of<0.3 ng/mL/mL could potentially avoid a prostate biopsy.

New model of PIRADS and adjusted prostatespecific antigen density of peripheral zone improves the detection rate of initial prostate biopsy:a diagnostic study

This study explored a new model of Prostate Imaging Reporting and Data System(PIRADS)and adjusted prostate-specific antigen density of peripheral zone(aPSADPZ)for predicting the occurrence of prostate cancer(PCa)and clinically significant prostate cancer(csPCa).The demographic and clinical characteristics of 853 patients were recorded.Prostate-specific antigen(PSA),PSA density(PSAD),PSAD of peripheral zone(PSADPZ),aPSADPZ,and peripheral zone volume ratio(PZ-ratio)were calculated and subjected to receiver operating characteristic(ROC)curve analysis.The calibration and discrimination abilities of new nomograms were verified with the calibration curve and area under the ROC curve(AUC).The clinical benefits of these models were evaluated by decision curve analysis and clinical impact curves.The AUCs of PSA,PSAD,PSADPZ,aPSADPZ,and PZ-ratio were 0.669,0.762,0.659,0.812,and 0.748 for PCa diagnosis,while 0.713,0.788,0.694,0.828,and 0.735 for csPCa diagnosis,respectively.All nomograms displayed higher net benefit and better overall calibration than the scenarios for predicting the occurrence of PCa or csPCa.The new model significantly improved the diagnostic accuracy of PCa(0.945 vs 0.830,P<0.01)and csPCa(0.937 vs 0.845,P<0.01)compared with the base model.In addition,the number of patients with PCa and csPCa predicted by the new model was in good agreement with the actual number of patients with PCa and csPCa in high-risk threshold.This study demonstrates that aPSADPZ has a higher predictive accuracy for PCa diagnosis than the conventional indicators.Combining aPSADPZ with PIRADS can improve PCa diagnosis and avoid unnecessary biopsies.

The combined role of MRI prostate and prostate health index in improving detection of significant prostate cancer in a screening population of Chinese men

Using prostate-specific antigen(PSA)for prostate cancer(PCa)screening led to overinvestigation and overdiagnosis of indolent PCa.We aimed to investigate the value of prostate health index(PHI)and magnetic resonance imaging(MRI)prostate in an Asian PCa screening program.Men aged 50–75 years were prospectively recruited from a community-based PSA screening program.Men with PSA 4.0–10.0 ng ml^(−1) had PHI result analyzed.MRI prostate was offered to men with PSA 4.0–50.0 ng ml−1.A systematic prostate biopsy was offered to men with PSA 4.0–9.9 ng ml^(−1) and PHI≥35,or PSA 10.0–50.0 ng ml^(−1).Additional targeted prostate biopsy was offered if they had PI-RADS score≥3.Clinically significant PCa(csPCa)was defined as the International Society of Urological Pathology(ISUP)grade group(GG)≥2 or ISUP GG 1 with involvement of≥30%of total systematic cores.In total,12.8%(196/1536)men had PSA≥4.0 ng ml^(−1).Among 194 men with PSA 4.0–50.0 ng ml^(−1),187(96.4%)received MRI prostate.Among them,28.3%(53/187)had PI-RADS≥3 lesions.Moreover,7.0%(107/1536)men were indicated for biopsy and 94.4%(101/107)men received biopsy.Among the men received biopsy,PCa,ISUP GG≥2 PCa,and csPCa was diagnosed in 42(41.6%),24(23.8%),and 34(33.7%)men,respectively.Compared with PSA/PHI pathway in men with PSA 4.0–50.0 ng ml^(−1),additional MRI increased diagnoses of PCa,ISUP GG≥2 PCa,and csPCa by 21.2%(from 33 to 40),22.2%(from 18 to 22),and 18.5%(from 27 to 32),respectively.The benefit of additional MRI was only observed in PSA 4.0–10.0 ng ml^(−1),and the number of MRI needed to diagnose one additional ISUP GG≥2 PCa was 20 in PHI≥35 and 94 in PHI<35.Among them,45.4%(89/196)men with PSA≥4.0 ng ml^(−1) avoided unnecessary biopsy with the use of PHI and MRI.A screening algorithm with PSA,PHI,and MRI could effectively diagnose csPCa while reducing unnecessary biopsies.The benefit of MRI prostate was mainly observed in PSA 4.0–9.9 ng ml^(−1) and PHI≥35 group.PHI was an important risk stratification step for PCa screening.

Computer-aided diagnosis and decision-making system for medical data analysis: A case study on prostate MR images

Prostate cancer is the most common cancer in males and a major cause of cancer-related death.Magnetic resonance(MR)imaging is recently emerging as a powerful tool for prostate cancer diagnosis.To clinically diagnose prostate cancer,doctors need to segment the prostate area in the MR image.However,manual segmentation is time consuming and influenced by the physician’s experience.Computer-aided diagnosis and decision-making systems have shown great effectiveness in assisting doctors for this purpose.At the same time,deep learning based on Generative Adversarial Networks can be applied to the segmentation of prostate MR images.In this paper,we propose a new computer-aided diagnosis and decision-making system based on a deep learning model to automatically segment the prostate region from prostate MR images.Additionally,receptive field block(RFB)was integrated into the model to enhance the discriminability and robustness of the extracted multi-scale features.We also introduced dense upsampling convolution instead of the traditional bilinear interpolation to capture and recover fine-detailed information.Adversarial training was used to train the model,and the segmentation results were experimentally tested.The results showed that adversarial training and RFB are indeed effective,and the proposed method is superior to other methods on various evaluation metrics.