The Study Of3.0T MRI And Vessel Permeability Imaging In The Prostate Diseases

Part Ⅰ3.0T MRI study of the short T2signal nodules of the peripheral zones of prostateObjectiveCommon scan, contrast-enhanced scan and dynamic contrast-enhanced scan by using3.0T MRI were performed in persons with normal prostate and patients with prostate cancers or other diseases confirmed operatively and pathologically by fifteen-needle biopsy, to investigate the basis of the short T2signal nodule formation of the peripheral zones in prostate, the differential diagnosis capability of common MRI in short T2signal nodules, the effect of the pre-operative tPSA in differentiating the benign and malignant of the short T2signal nodules,and to summarize the ratio of short and long diameter and to investigate its clinical value.Materials and Methods1. SubjectsAmong114suspected examiners with prostate carcinoma,70patients who underwent prostate routine MRI scanning before pathological examinations during Jan.2008to Dec.2011were selected for study with the age range of45-81years and the mean age of68.5years.These patients were divided into two groups as follows:PCa group, short for prostatic carcinoma nodule group,38lesions; NCa group, short for non-prostatic carcinoma nodule group,61lesions.2. Major equipment and contrsast mediumMRI scanner (Achieva3.0T,Holland Philips) with abdominal Torsol coil; Spectris solaris MR power injector (US MEDRAD); contrast agent, gadoiamide (4.31g/15mL)3. Examination methodsScanning sequence:routine axial T1WI and T2WI, coronal T2WI and sagittal T2WI. Axial plane T2WI+PS:TR/TE=4152/90ms, FOV=240×160, slice thickness=3mm, matrix=512×512, NEX=3. After gadoiamide contrast was administered by injection as0.1mmol per kilogram of body weight at a rate of2.5mL/s,15mLof normal saline was injected at a rate of2.3mL/s. The scanning parameters were as follows:TR/TE=3.4/1.7,3D-FFE; axial scanning first, slice thickness=3mm; then coronal and sagittal scanning, slice thickness=4mm; matrixs=512×512, NEX=2～3.4. Imaging evaluation and data processingThe short diameter, length and the ratio of the short and the length were measured and recorded. The values were measured3times and the mean was as a final value. Enhancement patterns were divided into3grades:0grade (no enhancement),1grade (slight enhancement or delayed) and2grade (severe enhancement or fast forward and dissipated)5. Statistical Method SPSS13.0software package was applied to deal with data of both parts of study. All data were recorded as (mean±tandard deviation),95%CI and the rang of all parameters. Statistical significance level was set as a=0.05, statictically significant difference was defined as P value less than0.05. Independent-samples t test or Wilcoxon rank test and receiver operating characteristic curve were performed for differentiation of group PCa and NCa.Results1. MRI findings and pathological basis of PCa and NCa groupsGroup PCa appeared as round nodules with clear boundary. Some of them protruded at the prostate capsule. There were5lesions at grade1enhanced and29at grade2. The other4were not performed enhancement scan. Tumor cells were polygonal or cube-shaped with dark and large nuclei; arranged closely as cords or nests; mostly lesions involved nerve, vessel, lymph or capsule.Group NCa showed streaky on T2WI, mostly limited to the peripheral zone of prostate. There were4kinds of pathological basis. Gland hyperplasia:9lesions,6at grade0enhanced and3at1grade; substrate proliferation:8lesions,7at grade0and1at grade2; mixed type:17lesions,3at grade0,12at grade1, and the other2lesions no enhancement exzamination.; inflammation type:27lesions,7at grade0,18at grade1and2with no enhancement exzamination.Enhanced model between PCa and NCa had significant differences (P=0.000).2. Measurement of short T2signal nodule of PZsThe average S/L were (70.52±13.74)%and (39.75±12.31)%in group PCa and NCa respectively. And the ratio of S/L differed significantly (P<0.001) The area under the ROC curve (AUCs) was0.959[95%CI:(0.925,0.993), P=0.000]. The sensitivity was0.921while the specificity0.918for differentiation of two groups when the S/L was53.55%. 3. Statistically significant difference was found in tPSA value between group PCa and NCa (P<0.05).Conclusions1. PCa nodules showed round lesion, while NCa nodules strip.2. PCa nodules had a grade of2enhancement while NCas just0or1grade. The enhancement of the former was stronger than the latter relevant to different pathological basis.3. The S/L ratio is useful for the routine clinical diagnosis.4. The pathological basis of short T2signal nodules included benign changes such as acute and chronic inflammation, gland hyperplasia and stoma fibrosis besides malignant prostate carcinoma.5. The tPSA contributed to the differential diagnosis between PCa and NCa. Part Ⅱ The3.0T MR vascular permeability imaging in prostatic carcinoma and benign hyperplasiaObjectiveDynamic contrast-enhanced scan by using3.0T MRI were performed in persons with normal prostate and patients with prostate cancer and benign hyperplasia, to evaluate the micro-vascular characteristics of prostate cancer by summarizing the value of micro-vascular parameters, such as Ktrans, Kep and Ve, among normal prostate, benign hyperplasia and cancer, and to investigate the correlation between Gleason score and tPSA of prostate carcinoma.Materials and Methods1. Subjects42examiners who underwent prostate DCE-MRI scanning before pathological examinations during Jan.2011to Dec.2011were selected for study. According to the inclusion criteria,9healthy subjects and31patients with prostate diseases were chosen. The latter were divided into three groups as follows:Ca group, short for prostatic carcinoma; N-Ca group, short for non-prostatic carcinoma in central area; N-PCa group, short for non-prostatic carcinoma in PZs.2. Major equipment, regents and examination methodsMajor equipment, regents and the routine MRI scanning parameters were the same as the part Ⅰ. DCE-MRI scanning sequence:axial contrast TiWI. FA=15°, TR/TE=5.5/3.6ms,3D-FFE, FOV=240×160×160mm, voxel=1.25×1.25×3mm, matrix=216×216, NEX=4. At the beginning of the forth dynamic gadoiamide contrast as15mL per person was injected at a rate of2.5mL/s, then15mL of normal saline injected at a rate of2.3mL/s.3. Imaging evaluation and data processing3.1Analysis softwareDCE_TOOLR2.3.6software package:jointly developed by Philips Corporation and the U.S. National Institutes of Health. It can afford parameters as Ktrans, Kep and Ve of Per-MRI.3.2Prostate zoning ruleAccording to the axial T2WI, the prostate was divided into5zones and15districts as figure1. And we should adjust the non-15-needle biopsy on the above areas. When the PZs were pressed into a linear, the central area was divided into3zones as figure2.3.3Sampling and grouping methodsA specimen:a zone of PZs or a whole central area. No matter where the cancer foci was, in a zone or a district of central area, as a specimen. The parameter values for each plot confirmed as cancer foci points were calculated and then the average was taken as the final parameter values of the specimen. The cancer foci point from PZs or central area was classified to group Ca. Group N-Ca came from central area while group N-PCa PZs. All the values were measured3times and the mean was as a final value. The measured values included Ktrans and Kep.Ve was equal to Ktrans divided by Kep.3.4Setting of ROIThe size of ROI:25-30mm. When the PZs were pressed into a linear or the central area was too small to suit for the zone laws, the conformal ROI of the software was used at the least of16mm2.4. Statistical MethodAll data were recorded as (mean±tandard deviation),95%CI and the rang of all parameters. One-way ANOVA test, ROC curve and Pearson correlation test were performed.Results1. Non-quantitative analysis of Per-MRI among healthy examinersThe PZs showed crescent-shaped black impact of almost young and middle-aged examiners (6/9) while the central area purple-blue. The time-uptake curve showed large spacing between the femoral artery input curve and the prostate.2. Pathological findings of31patientsNon-prostate cancer patients:21cases, tPSA (13.02±2.28) μg/L, f/t (18.77±3.11)%; Prostate cancer patients:10cases, tPSA (29.92±16.05) μg/L, f/t (15.45±2.57)%, and the Gleason score between4to7:6cases,8to10:2cases.Sample sizes were as follows:20specimens of group Ca,23specimens of group N-Ca and46specimens of group N-PCa.3. Non-quantitative analysis of Per-MRI among patientsThe prostate central hyperplasia area displayed uneven color merging carcinogenesis or not. Per-MRI showed foci of carcinoma on the PZs earlier than T2WI and DWI. Per-MRI can also showed neurovascular bundle clearly on the poster lateral PZs.4. Quantitative analysis of Per-MRI among patientsThere was significant difference in the values of Ktrans, Kep and Ve among group Ca, group N-Ca and group N-PCa (P=0.000). The values of Ktrans in group Ca were significant higher than those in group N-Ca (P=0.013), while there were no significant difference of values of Kep and Ve (P>0.05). The values of Ktrans, Kep and Ve of the group Ca and N-Ca were significant higher than those in group Ve (P=0.000). The values of Ktrans in group Ca sourcing from central area was significant higher than PZs (P=0.003), while there were no significant difference of values of Kep and Ve between them. There was no correlation between Gleason score and valules of tPSA, f/t%, Ktrans, Kep and Ve (P>0.05).Conclusions1. The value of Ktrans of the group Ca was higher than it from group N-Ca. The values of Ktrans, Kep and Ve of groups Ca and N-Ca were higher than those of group N-PCa. The value of Ktrans in group Ca sourcing from central area was significant higher than PZs.2. There was no correlation between Gleason score and valules of tPSA, f/t%, Ktrans, Kep and Ve.3. The pseudo-color images of Per-MRI showed lower microvascular permeability of PZs than it of the central area because of the histological foundation. But it was difficult for the pseudo-color images of Per-MRI to show whether the central area merging carcinoma. Per-MRI showed foci of carcinoma on the PZs earlier than T2WI and DWI.