Application Value Of Susceptibility-weighted Imaging And Diffusion-weighted Imaging In Differential Diagnosis And Efficacy Prediction Of Primary Central Nervous System Lymphoma

Part 1 Application Value of Susceptibility Weighted Imaging and Diffusion Weighted Imaging in Differential Diagnosis of Primary Central Nervous System Lymphoma and GlioblastomaObjective To investigate the clinical value of susceptibility weighted imaging（SWI）and diffusion weighted imaging（DWI）on differential diagnosis between primary central nervous system lymphoma（PCNSL）and glioblastoma.Methods and Methods 18 cases of PCNSL and 21 cases of GBM from January 2010 to December 2021 were collected.All patients were confirmed by pathology,and PCNSL was clinically diagnosed.Before the pathological results were obtained,radiotherapy,chemotherapy and hormone therapy were not be administered.All MRI images were analyzed by 2 attending physicians.If there was disagreement,a deputy chief physician participated in the discussion and reached an agreement.The content of the analysis was as follows:extraction of mean apparent diffusion coefficient（ADCmean）,semi-quantitative rating of intratumoral susceptibility signal intensity（ITSS）（grade 0-3）,diagnostic score based on T1WI enhanced image（1～4 points）etc.All numerical variables were normally distributed using the Kolmogorov-Smirnov test,and those that conformed to the normal distribution were expressed as the mean ± standard deviation,and those that did not conform to the normal distribution were expressed as the median（interquartile range）.The independent samples t-test was used if data was conformed to the normal distribution,and the Mann-Whitney U test was used if data was not conformed to the normal distribution,in order to analyze the differences between the two groups of numerical variables;the chi-square test was used to analyze the differences between the two groups of categorical variables.The receiver operating characteristic（ROC）curve was used to evaluate the differential diagnosis performance of ADCmean,ITSS grading and diagnostic score based on T1WI enhanced image,and the optimal threshold,area under the curve（AUC）,sensitivity,specificity,accuracy,positive predictive value（PPV）,negative predictive value（NPV）were obtained.When multiple indicators were combined,Binary Logistic is used to perform stepwise Logistic regression analysis to generate overall predictive probability variables.Results The mean age of PCNSL was 61.7±10.17 years;the mean age of GBM was 53.1± 13.65 years.There were 8 cases of multiple,10 cases of single,13 males and 5 females in PCNSL;There were 5 cases of multiple,16 solitary cases,13 males and 8 females in GBM.On PCNSL,The average ADCmean was（795.6±154.22）×10-6 mm2/s,the median ITSS was 1（interquartile range:2）grade,and the median diagnostic score was 1（Interquartile range:1）points,the median maximum diameter is 35.44（interquartile range:15.83）cm;on GBM,the average ADCmean is（1020.43±248.281）×10-6mm2/s,the median value was 3（interquartile range:1）grade in ITSS,the median diagnostic score was 3（interquartile range:2）points,and the median maximum diameter was 49.12（interquartile range:31.53）mm.The independent samples t test showed that ADCmean and age were statistically different（p=0.002,p=0.034）,and the Mann-Whitney U test showed that there were statistically different on the maximum diameter（p=0.037）,ITSS（p<0.001）)and diagnostic score（p=0.001）between PCNSL group and GBM group.ROC analysis demonstrated that the combination of multi-indicator（ITSS+ADCmean+diagnostic score based on T1WI enhanced image）AUC was the largest at 0.976 on differential diagnosis,followed by dual-indicator combined differential diagnosis（ITSS+ADCmean）AUC was 0.934;among the single indicators,ITSS had the largest AUC at 0.841.Conclusion DWI and SWI based on plain scan have clinical application value in the differential diagnosis of PCNSL and GBM.They are easy to implement,and are more suitable for clinical practice and promotion.Part 2 Preliminary Study on the Prediction of Chemotherapy-responsive and Progression-free Survival by Susceptibility-weighted Imaging and Diffusion Weighted Imagingin Primary Central Nervous System LymphomaObjective To analyze the predictive value of susceptibility weighted imaging（SWI）and diffusion weighted imaging（DWI）for chemotherapy responsiveness and progression-free survival（PFS）in primary central nervous system lymphoma（PCNSL）.Materials and Methods 15 cases of PCNSL,confirmed by clinically and pathologically,were collected.Before chemotherapy,MRI plain scan and enhanced scan,DWI and SWI scan were performed,and intratumoral susceptibility signal intensity（ITSS）was evaluated on SWI,the mean apparent diffusion coefficient（ADCmean）of tumor was obtained on the DWI-derived ADC map.ITSS observation results were recorded by the two doctors according to the grades（0～3）;based on the presence or absence of ITSS and ITSS grading,the Kappa consistency test was carried out for consistency of evaluation.TheITSS gradingwas revised after discussion.Allnumerical variables were normally distributed using the Kolmogorov-Smirnov test,and those that conformed to the normal distribution were expressed as the mean±standard deviation,and those that did not conform to the normal distribution were expressed as the median（interquartile range）.The average value was used as the cutoff value for those with normal distribution,and the median value was used as the cut off value for those with non-normal distribution.The PFS was divided into two groups according to the cutoff value,and the initial efficacy after 4 cycles of chemotherapy was divided into complete remission（complete remission,CR）and non-CR,and then,the maximum diameter,age,ADCmean,and revised ITSS grading were divided into high and low groups based on the cut-off value,single and multiple groups were assigned based on the number of enhancing tumor,and two groups（male vs.Female）were assigned according to gender,two groups were assigned based on the presence or absence of ITSS.Finally,tables were established respectively and Fisher’s exact probability chi-square test was used to analyze whether there were statistical differences in the number of cases between high and low PFS orbetween CR and non-CRbased on groups with differentindicator status.Based on the table,the predictive sensitivity,specificity and accuracy of the existence status of ITSS and the level of ADCmean were calculated and obtained on PFS and the initial response of 4 cycles of chemotherapy.Results Age,PFS and ADCmean were conformed to normal distribution,while revised ITSS grading and maximum diameter were not conformed to normal distribution.Age was 46～79 years,mean age was 60.7±9.26 years.PFS was 3-30 months,mean PFS was 13.1±7.49 months.Revised ITSS grade was 0-3,median was 1（interquartile range:2）,9 cases revealed ITSS.ADCmean was 460～1159×10-6mm2/s,mean 796.5±168.25×10-6mm2/s;maximum diameter was 24.84～78.75mm,median was 35.25（interquartile range:21.10）mm.There were 10 males and 5 females.The initial efficacy was CR in 9 cases and non-CR in 6 cases.Between the two groups with high and low PFS,there were statistically significant differences in the number of cases between high and low age（p=0.001）,with or without ITSS（p=0.001）,high and low ADCmean（p=0.041）,and different initial efficacy（p=0.007）.Between different initial efficacy（CR and non-CR）,the number of cases between high and low age（p=0.001）,different PFS（p=0.007）,presence or absence ITSS（p=0.028）,and high and low ADCmean（p=0.035）were significantly different.Based on presence of ITSS,the sensitivity,specificity and accuracy of predicting PFS≤13 months and non-CR were 100%,86%and 93%,100%,67%and 80%,and based on ADCmean≤796×10-6 mm2/s,the sensitivity,specificity and accuracy of prediction were 75%,86%and 80%,83%,78%and 80%.The performance of ITSS in predicting PFS was better than ADCmean.Conclusions SWI and DWI based on plain scan maybe predict chemotherapy responsiveness and PFS in PCNSL,and the method of estimating the presence or absence of ITSS on SWI is simpler and more practical.