| Objective:To explore the value of multi-parameter quantitative analysis in the diagnosis of prostate cancer,obtain the best parameters and cut-off value in the diagnosis of prostate cancer.Meanwhile explore differences of various parameters among different grades of prostate cancer.To define the main MRI characteristics of prostate cancer after Argon-Helium cryoablation and to assess the effect of cryotherapy.To evaluate the ability of multi-parameter MRI in recognizing prostate cancer recurrence after Argon-Helium cryoablation.Subjects and Methods:?1?Patients underwent multi-parameter MRI of prostate in our hospital from March 2015 to September 2017 and patients who met the inclusion criteria were enrolled into this study.Prostate multi-parameter imagings were performed using 3.0 T MRI.A total of 44 cases of prostate cancer and 30 cases of benign prostatic hyperplasia were enrolled in this study to observe the signal characteristics and focal lesion characteristics of prostate cancer,prostate hyperplasia in T1WI,T2WI,IVIM and DCE-MRI images.Quantitative measurements of each quantitative parameter?D value,D*value,f value,skew,kurtosis,peak value?of each region of interest?ROC?in peripheral zone,central glandular zone,iliac bone of prostate hyperplasia and prostate cancer zone were measured respectively.To compare the differences among groups.The ROC curve was used to compare the diagnostic value of each quantitative value to prostate cancer and to confirm the best diagnostic threshold.Prostate cancer zones were divided into low to middle groups??7 points?and high-level group??8 points?according to Gleason score,the differences between the two groups were compared.?2?From January 2013 to September 2017,32 patients with pathological confirmed prostate cancer who were performed Argon-Helium cryoablation were retrospectively analysis?mean age 65,range 54-80?.All patients were performed pre-operative and post-operative multi-parameter MRI scans.Signals,quantitative parameters of cryonecrotic region and their differences between routine MRI and functional MRI were assessed.The morphology and signal change of urethra and pelvic floor muscles adjacent to cryogenic region were also evaluated.The effects of cryotherapy were evaluated to determine whether the tumor was cured,remnant,or with recurrence.Functional MRI could be used to differentiate occurrence from benign therapeutic reaction in prostate cancer patients after Argon-Helium cryoablation.Results:?1?The signal of peripheral zone and central gland in normal prostate decreased gradually with the increase of b value in IVIM sequence,while the signal of prostate cancer foci increased gradually.The diffusion coefficient?D?values of prostate cancer,peripheral zone of prostate hyperplasia and central gland of prostate hyperplasia were?0.561±0.350?×10-3 mm2/s,?1.264±0.299?×10-3 mm2/s,?0.875±0.156?×10-3 mm2/s respectively;the f values were 0.275±0.094,0.340±0.122,0.339±0.069 respectively;D*values were?9.865±3.195?×10-3 mm2/s,?9.717±4.211?×10-3 mm2/s,?9.472±2.672?×10-3 mm2/s respectively.There was significant difference between any two groups in the value of D?P<0.05?.The value of D in prostate cancer was significantly lower than that in peripheral zone and central gland,the D value in the peripheral zone was highest of the three.The f value of prostate cancer was lower than that of the peripheral zone and the central gland of the prostate?P<0.05?.Histogram analysis of skew?D?in prostate cancer were all statistically significant compare to peripheral zone and central gland,kurtosis?D?was only different compare to peripheral zone.Peak value?D?,peak value?f?in prostate cancer was statistically decreased compare to the peripheral zone.D,D*values in iliac bone metastases were significantly higher than normal iliac.The ROC curves were drawn according to the diagnostic criteria of each parameter.f value was of moderate diagnostic efficacy,D value has the highest diagnostic efficacy to differential diagnosis of prostate cancer.The thresholds to the diagnosis of PCa in D was 0.709×10-3 mm2/s,The sensitivity,specificity of the diagnosis of PCa were?95%?90.7%?;the thresholds in f was 0.289,The sensitivity,specificity of the diagnosis of PCa were?75%?68.2%?.There was statistically significant difference in skew?D?between low-grade and high-grade prostate cancer.?2?The prostate size of1 month post-operative became larger and shrinked after 1 month.Some patients reached radical cure after 3 months.No specific characteristic was noticed on T1WI or T2WI images after surgery,while DCE-MRI explicitly showed relatively specific circular enhancement which faded in the follow-up.Post-operative DWI or IVIM images illustrated three layers with mixed hypo-and hyper-intensity,and the central part demonstrated two signals representing coagulation necrosis and liquefaction necrosis,respectively.In the early stage,recurrence lesion presented as marked homogenous nodule and adjacent structures showed slow and homogenous enhancement.Recurrence was enhanced earlier and faster compared to fibrosis tissue and residual normal prostate tissue with restricted diffusion and lower ADC and D values.Conclusion:?1?The prostate IVIM scan can be used to obtain information on the diffusion and perfusion of the prostate tissue,which is of value in the diagnosis of prostate cancer.The D value has certain advantages in the diagnosis of prostate cancer.IVIM parameters do not show advantages in the determination of prostate cancer invasiveness,and further large sample studies are still needed.?2?Post-operative prostate and adjacent structures showed certain imaging features that could help monitor the size and range of cryonecrotic region damage and determine the ablation border.Signal characteristic in cryonecrotic region could differentiate necrosis types.Application of multi-parameter functional MRI could be of great value in differentiating recurrences in prostate cancer after Argon-Helium cryoablation. |
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