The Application Of Magnetic Resonance Imaging In Testis

Part? Multi-model analysis of diffusion-weighted imaging of normal testes at 3.0 T: preliminary findingsObjectives: To establish diffusion quantitative parameters(ADC,DDC,?,Dapp,and Kapp)in normal testes at 3.0 T.Materials and methods: Sixty-four healthy volunteers in two age groups(A: 10–39 years;B: ?40 years)underwent diffusion-weighted imaging scanning at 3.0 T.ADC1000,ADC2000,ADC3000,DDC,?,Dapp,and Kapp were calculated using the mono-exponential,stretched-exponential and kurtosis models.The correlations between parameters and the age were analyzed.The parameters were compared between the age groups and between the right and left testes.Results: The average ADC1000,ADC2000,ADC3000,DDC,?,Dapp,and Kapp values did not significantly differ between the right and left testes(p>0.05 for all).The following significant correlations were found: positive correlations between age and testicular ADC1000,ADC2000,ADC3000,DDC and Dapp(r=0.516,0.518,0.518,0.521 and 0.516,respectively;p<0.01 for all)and negative correlations between age and testicular ? and Kapp(r=-0.363,-0.427,respectively;p<0.01 for both).Compared to group B,in group A,ADC1000,ADC2000,ADC3000,DDC and Dapp were significantly lower(p<0.05 for all),but ? and Kapp were significantly higher(p<0.05 for both).Conclusions: Our study demonstrated the applicability of the testicular mono-exponential,stretched-exponential and kurtosis models.Our results can help establish a baseline for the normal testicular parameters in these diffusion models.The contralateral normal testis can serve as a suitable reference for evaluating the abnormalities of the other side.The effect of age on these parameters requires further attention.Part ?Radiomic Signature as a Diagnostic Factor in differentiating benign and malignant testicular lesionsPurpose: To assess the diagnostic accuracy of radiomics signature based on magnetic resonance imaging(MRI)in differentiating benign and malignant testicular lesions.Materials and methods: The local review board approved this retrospective study.66 patients(median age,29 years;age range,8–72 years)with testicular lesions were consecutively enrolled between July 2014 and May 2017.We extracted 1669 features from a manually outlined lesion region on T2-weighted images.The maximum relevance minimum redundancy(m RMR)and least absolute shrinkage and selection operator(LASSO)logistic regression model were implemented to select features.Radiomics signatures were obtained with the LASSO logistic regression model.Receiver operating characteristic analysis was used to evaluate the diagnostic accuracy of the radiomic signatures.Results: Four features were selected to construct the radiomic signature for differentiating benign and malignant testicular lesions.The performance of the radiomic signature in identifying benign from malignant testicular lesions was good,with an AUC of 0.915(95% confidence interval [CI]: 0.836 to 0.964),sensitivity of 90.90(95% CI: 78.3-97.5%),and specificity of 84.10(95% CI: 69.9-93.4%).Conclusion: MRI-derived textural features could serve as a noninvasive diagnostic tool in differentiating benign and malignant testicular lesions.Part ? Characterization of testicular germ cell tumors: Whole-lesion histogram analysis of the apparent diffusion coefficient at 3TPurpose: To assess the values of parameters derived from whole-lesion histograms of the apparent diffusion coefficient(ADC)at 3T for the characterization of testicular germ cell tumors(TGCTs).Materials and methods: A total of 24 men with TGCTs underwent 3T diffusion-weighted imaging.Fourteen tumors were pathologically confirmed as seminomas,and ten tumors were pathologically confirmed as nonseminomas.Whole-lesion histogram analysis of the ADC values was performed.A Mann-Whitney U test was employed to compare the differences in ADC histogram parameters between seminomas and nonseminomas.Receiver operating characteristic analysis was used to identify the cutoff values for each parameter for differentiating seminomas from nonseminomas;furthermore,the area under the curve(AUC)was calculated to evaluate the diagnostic accuracy.Results: The median of 10 th,25th,50 th,75th,and 90 th percentiles and mean,minimum and maximum ADC values were all significantly reduced for seminomas compared with nonseminomas(p < 0.05 for all).In contrast,the median of kurtosis and skewness of ADC values of seminomas were both significantly increased compared with those of nonseminomas(p = 0.003 and 0.001,respectively).For differentiating nonseminomas from seminomas,the 10 th percentile ADC yielded the highest AUC with a sensitivity and specificity of 100% and 92.86%,respectively.Conclusion: Whole-lesion histogram analysis of ADCs might be used for preoperative characterization of TGCTs.