| The first part:Intravoxel incoherent motion MR imaging for diagnosis of prostate cancer: an evaluation of optimal b value combinationObjective To explore the role of IVIM quantitative parameters to help diagnose prostate cancer and optimize the b-value pairs. Methods IVIM-DWI was performed in forty-seven patients confirmed of prostate cancer with biopsy. ROI was drawn on the map of IVIM parameters to measure the D, D*and f value corresponding to different bvalue combinations. Parameters of prostate cancer zone, non-cancerous peripheral zone and non-cancerous central gland zone were evaluated with variance analysis and LSD method was used to test the difference between each two. Results Group(1):the IVIM parameters(f, D*, D) obtained in prostate cancer area were(26.95 ± 4.75)%、(12.88 ± 4.93)×10-3mm2/s、(0.67 ± 0.11)×10-3mm2/s.(27.79 ± 3.47)%、(15.6 ± 2.82)×10-3mm2/s、(1.35 ± 0.16)×10-3mm2/s in non-cancerous central gland and(25.19 ± 4.3)%、(13.47 ± 4.84)×10-3mm2/s、(1.79 ± 0.29)×10-3mm2/s in non-cancerous peripheral zone.Group(2):the IVIM parameters(f, D*, D) obtained in prostate cancer area were(26.45 ± 4.73)%、(13.1 ± 4.44)×10-3mm2/s、(0.68 ± 0.14)×10-3mm2/s.(27.3 ± 4.06)%、(15.41 ± 3.46)×10-3mm2/s、(1.36 ± 0.17)×10-3mm2/s in non-cancerous central gland and(23.9 ± 3.54)%、(12.22 ± 4.61)×10-3mm2/s、(1.85 ± 0.29)×10-3mm2/s in non-cancerous peripheral zone.Group(3):the IVIM parameters(f, D*, D) obtained in prostate cancer area were(25.59 ± 4.84)%、(13.75 ± 5.08)×10-3mm2/s、(0.68 ± 0.12)×10-3mm2/s.(26.78 ± 3.86)%、(15.55 ± 2.82)×10-3mm2/s、(1.38 ± 0.16)×10-3mm2/s in non-cancerous central gland and(23.98 ± 5.2)%、(13.55 ± 5.27)×10-3mm2/s、(1.8 ± 0.31)×10-3mm2/s in non-cancerous peripheral zone.Group(4):the IVIM parameters(f, D*, D) obtained in prostate cancer area were(28.58 ± 5.93)%、(12.43 ± 5.55)×10-3mm2/s、(0.67 ± 0.13)×10-3mm2/s.(28.2 ± 3.16)%、(14.38 ± 3.15)×10-3mm2/s、(1.33 ± 0.16)×10-3mm2/s in non-cancerous central gland and(28 ± 6.93)%、(11.41 ± 5.64)×10-3mm2/s、(1.81 ± 0.35)×10-3mm2/s in non-cancerous peripheral zone.D value in cancer areaswas lower than that in non-cancerous areas, and the difference was statistically significant(P <0.05). D value of non-cancerous central gland region was less than that of the non-cancerous peripheral areas, and the difference was statistically significance(P <0.05). Conclusion D value of all four groups can be used to help diagnose prostate cancer, and the first group contained the minimum number of b values(0,10,100,200,1000), which leaded to the shortest scan time.The second part: Study of consistency of Intravoxel incoherent motion imaging in prostateObjective Intravoxel incoherent motion imaging of prostate was performed on volunteers to discuss the consistency and reproducibility of IVIM parameters. Methods 15 cases of young volunteers underwent IVIM inspectionat 3.0T Philips MRI, and the same physician repeated the scan after an interval of 16 days at 3.0T Philips and 3.0TX Philips. Intravoxel incoherent motion parameters were measured on intravoxel incoherent motion maps. Different programs were compared fordifferences in IVIM parameters and the interclass correlation coefficient(ICC) were also calculated. Paired t test and Bland-Altman plot were also applied. Results Parameters(D, f, D*)measured in central gland at the first time on 3.0T Philips were(1.35 ± 0.22)×10-3mm2/s,(33.33 ± 7.28)%,(14.28 ± 4.05)×10-3mm2/s, parameters measured in peripheral zone were(1.32 ± 0.14)×10-3mm2/s,(34.15 ± 7.34)%,(13.09 ± 3.20)×10-3mm2/s. Parameters measured in central gland at the second time on 3.0T Philips were(1.34 ± 0.16)×10-3mm2/s,(31.67 ± 5.34)%,(14.21 ± 3.53)×10-3mm2/s, parameters measured in peripheral zone were(1.35 ± 0.09)×10-3mm2/s,(34.05 ± 8.36)%,(12.94 ± 4.41)×10-3mm2/s. Parameters measured in central gland at the second time on 3.0TX Philips were(1.42 ± 0.19)×10-3mm2/s,(33.81 ± 5.77)%,(33.81 ± 5.77)×10-3mm2/s, parameters measured in peripheral zone were(1.31 ± 0.28)×10-3mm2/s,(32.83 ± 10.34)%,(12.43 ± 3.80)×10-3mm2/s. The same physician reproduced the same images obtained from the first scan on 3.0T Philips, parameters showed(1.31 ± 0.11)×10-3mm2/s,(34.64 ± 7.70)%,(13.98 ± 4.01)×10-3mm2/sin central gland and(1.32 ± 0.16)×10-3mm2/s,(33.20 ± 5.41)%,(13.46 ± 2.67)×10-3mm2/s in peripheral zone. The same physician used different programs to measure D, f, D* value, and there was no significant difference(P>0.05). The relative ICC in central gland were 0.794~0.910,0.460~0.769,0.520~0.735, respectively.The relative ICC inperipheral zone were 0.836~0.934, 0.523~0.803, 0.630~0.870, respectively. Bland-Altman scatter plot showed that D value appropriately improved consistency and can provide more reproducible and stableresults. Conclusion Threeprostate IVIM parameters(D, D * and f) were measured under different scenarios, and D value showed better consistency than the other two. |
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