Abstract:

Objective To explore the application value of ADC and rADC values in the differential diagno⁃ sis of PCNSL and HGG as well as the correlation with Ki⁃67 in different tumor regions. Methods Clinical and imaging data of 30 cases of PCNSL and 35 cases of HGG were collected，the characteristics of MRI and DWI of 30 cases of PCNSL and 35 cases of HGG confirmed by clinical and pathology were analyzed. The differences of ADC values in different regions of the two groups of tumors were compared，and ROC curves were drawn to analyze and compare the diagnostic efficacy of ADC and rADC values in the two groups of tumors.The correlation was analyzed between tumor parenchymal ADC and rADC and Ki⁃67 in PCNSL group. Results There were statistically signifi⁃ cant differences in ADC values of tumor parenchyma，proximal peritumor，distal peritumor and contralateral white matter in PCNSL（F = 278.758，P < 0.001）. Pair comparison showed statistically significant differences（P < 0.05）. The parenchymal ADC values，ADC values around the proximal tumor and ADC values around the distal tumor in the PCNSL and HGG groups showed a parabola pattern of rising first and then falling，and a broken line pattern of rising.The ADC value and rADC value of tumor parenchyma and distal peritumor ADC value and rADC value of PCNSL were significantly lower than those of HGG group（P < 0.001），while the ADC value and rADC value of proximal peritumor ADC value and rADC value of PCNSL were significantly higher than those of HGG group（P<0.001）. When the rADC value of tumor parenchymal was 1.045，the sensitivity，specificity and accuracy of differ⁃ ential diagnosis of PCNSL and HGG were 96.7%，85.7% and 90.8%，respectively. The area under the rADC value curve was the largest（AUC = 0.964），and the diagnostic efficiency was the highest.Ki⁃67 expression was negatively correlated with ADC and rADC values. Conclusion The measurement techniques of ADC value and rADC value provide pathological basis and molecular imaging basis for noninvasive determination of tumor and peri⁃tumor micro⁃ invasion state，provide reliable basis for the diagnosis and differentiation of PCNSL and HGG，and also reflect the value⁃added activity of PCNSL at the molecular level.

Key words:

lymphoma； glioma； central nervous system； magnetic resonance imaging； apparent diffusion coefficient； Ki?67 ,