Diagnostic Value And Risk Assessment Of Multimodal Magnetic Resonance Imaging In Prostate Cancer

BackgroundProstate cancer(PCa)is one of the most common malignant tumors in the urogenital system of middle-aged and eldly men,and it is also the second most common tumor in men.There are obvious regional and ethnic differences in the incidence of prostate cancer.In recent years,the incidence rate of PCa in China has also been rising.The treatment plan and prognosis of patients differs according to risk.Early PCa can be treated actively to achieve a higher five-year survival.However,the five-year survival rate of patients with advanced prostate cancer is significantly low.Therefore,early diagnosis and accurate assessment of PCa and its risk is the key to improve the quality of life and reduce mortality.Magnetic Resonance Imaging(MRI)is currently recognized as the best imaging technology for the diagnosis and differential diagnosis of prostate diseases,and multi parameter MRI has been used in the research and diagnosis of PCa.Amide proton transfer(APT)imaging and diffusion kurtosis imaging(DKI)are newly developed MRI technologies in recent years.These new technologies can detect the content of macromolecules / polypeptides in PCa tissues and the microscopic information of water molecule diffusion in the tumor,providing reference for the diagnosis,risk assessment and treatment of PCa in clinic.Part ? The Diagnostic Value and Risk Assessment of Amide Proton Transfer weighted Imaging in Prostate Cancer ObjectiveTo investigate the diagnostic value of proton Amide proton transfer weighted imaging(APTWI)in prostate cancer,and the value of its risk assessment.Materials and MethodsA total of 39 patients with PCa who underwent MR examination in our hospital from August 2017 to May 2018 and underwent biopsy or pathology were collected.Before operation,conventional sequences(axial,sagittal,coronal T1 WI and T2WI),diffusion weighted imaging(DWI)and APT were performed.All the scanned images are transmitted to the post-processing workstation,and two radiologists measure the asymmetric magnetic transfer ratio of PCa tissue at 3.5ppm,MTRasym(3.5ppm)was used to analyze the measured parameters,and to compare the difference of MTRasym values between cancer area and non cancer area.According to Gleason score(GS > 7 for high-risk group,GS = 7for middle-risk group,GS < 7 for low-risk group),the risk of PCa area was divided into high,middle and low-risk groups(20 cases in high-risk group,14 cases in middle-risk group,5 cases in low-risk group),and the difference of MTRasym value between groups in pathological area was compared.Receiver operating characteristic(ROC)curve was used to evaluate the diagnostic efficacy of each parameter,and Spearman's rank correlation was used to analyze the correlation between MTRasym value and Gleason score.ResultsThe MTRasym value of PCa area was significantly higher than that of non cancer peripheral tissue(P > 0.05).There was significant difference in MTRasym between low-risk group and high-risk group,middle-risk group and high-risk group(P < 0.05).Gleason score was positively correlated with MTRasym value(r = 0.568,P < 0.05).The area under the curve of low-risk group and middle-risk group,middle-risk group and high-risk group,low-risk group and high-risk group were 0.657,0.814 and 0.890 respectively.The diagnostic threshold was 3.69%,3.99%,4.67%;the sensitivity was100.0%,100.0%,65.0%;the specificity was 40.0%,57.1%,100.0%;and the Youden's index was 0.400,0.571,0.650,respectively.ConclusionAPT has the ability of preliminary diagnosis and identification of PCa,and can predict its risk,which provides a reference for clinical diagnosis and treatment of PCa.Part ? The Diagnostic Value and Risk Assessment of Diffusion Kurtosis Imaging in Prostate CancerObjective To explore the value of diffusion kurtosis imaging(DKI)in the diagnosis of prostate cancer(PCa),and the value of its risk assessment.Materials and Methods From October 2017 to December 2018,DKI sequence image data of 45 patients with PCa who were examined in MR of our hospital and confirmed by pathology or biopsy were collected.Before operation,all patients underwent conventional sequence(axial,sagittal,coronal T1 WI and T2WI),oblique diffusion weighted imaging(DWI)and diffusion kurtosis imaging(DKI).The mean kurtosis(MK)value and mean diffusivity(MD)value of cancer area and non cancer peripheral tissue were measured.The parameters were analyzed by related statistical software,and the differences of MK value and MD value of cancer area and non cancer area were compared,respectively.According to Gleason score(GS > 7 for high-risk group,GS = 7 for middle-risk group,GS < 7 for low-risk group),the risk of PCa area was divided into high,middle and low risk groups(23cases in high-risk group,13 cases in middle-risk group,9 cases in low-risk group),and the differences of MK and MD values between different groups in the lesion area were compared.Receiver operating characteristic(ROC)curve was used to evaluate the diagnostic efficacy of each parameter,and Spearman's rank correlation was used to analyze the correlation between MK value,MD value and Gleason score.Results The values of MK and MD in PCa area were significantly higher than those in non cancer peripheral tissues(P < 0.05).There was no significant difference in the values of MK and MD between low-risk group and middle-risk group(P > 0.05).There was significant difference in the values of MK and MD between the low-risk group and the high-risk group,the middle-risk group and the high-risk group(P < 0.05).Gleason score was positively correlated with the values of MK(r = 0.827,P < 0.05),and negatively correlated with the values of MD(r =-0.801,P < 0.05).The area under the curve of MK /MD was 0.838/0.769;the diagnostic threshold was 1.02/0.85,1.10/0.77,1.02/0.81;the sensitivity was 69.23%/84.62%,60.87%/65.22%,95.65%/86.96%;the specificity was88.89%/66.67%,92.31%/92.31%,88.89%/100.00%;and the Youden's index was0.581/0.513?0.532/0.575?0.845/0.869,respectively.Conclusion DKI has the potential to diagnose PCa and evaluate its risk degree,which can provide reference and have an important impact on clinical diagnosis and treatment of PCa.