High B-value Diffusion MR Imaging In The Evaluation Of High-grade Gliomas And Solitary Metastases

Objective：To investigate the signal changes in Diffusion weightedimaging at different b-values of the brain tumors，and to research the effect ofdifferent b values on signal intensitys（SIs），ADC,signal to noise ratio andcontrast ratio.Materials and Methods：Three different b-values (b=1000s/mm~2，3000s/mm~2,5000s/mm~2)were applied in forty patients with brain tumors，measuring the SIs and ADC value in regions of tumor, peritumoral edemaand the Contralateral normal brain tissues.We also measure the noise SIs andthe standard deviation in regions of background.Results:1、The SIs in all ROIs were significant decreased with theincreasing of b-value(p＜0.05). From1000s/mm~2to3000s/mm~2，the SIs ofthe regions of interes（tROI）drop51.5%、80.6%、36.7%，respectively. From3000s/mm~2to5000s/mm~2,the SIs of ROIs drop67.6%、86.6%、58.7%，respectively.2、The ADC in all ROIs were significant decreased with the increasing ofb-value(p=0.000). From1000s/mm~2to3000s/mm~2，the ADC of the ROIsdrop51.1%、30.4%、31.5%，respectively. From3000s/mm~2to5000s/mm~2,that drops65.5%、53.2%、49.8%，respectively.3、The SNR in all regions were decreased with the increasing ofb-value.The SNR in the regions of tumor were significant decreased between 1000s/mm~2and3000s/mm~2，and1000s/mm~2and5000s/mm~2(p=0.000).There were significant difference between three b-values of the SNR in theregions of peritumoral edema (p＜0.05).4、The contrast ratio(CR)of tumor to peritumoral edema were increasedwith the increasing of b-value.When b value is5000s/mm~2，the CR is0.44±0.21.There were significant difference between1000s/mm~2and3000s/mm~2,1000s/mm~2and5000s/mm~2(p=0.000).Conclusion:With the increasing of b-value, signal intensitys（SIs），ADC,signal to noise ratio in regions of tumor, peritumoral edema andContralateral normal brain tissue were decreased.The decrease of signalintensity（SI）in region of peritumoral edema is the most obvious, and themost obvious decrease of ADC is in the region of tumor. High b-value（b=5000s/mm~2）is better to display the contrast difference between tumorand peritumoral edema than the other b-values. Objective：To research the effect of three different b values on thediagnosis and differential diagnosis between high-grade gliomas and solitarymetastases in the regions of tumor and peritumoral edema，and to find themost optimal b values to diagnose the two types of tumor. Materials and Methods: Three different b-values (b=1000s/mm~2，3000s/mm~2,5000s/mm~2)were applied in twenty five patients diagnosed ashigh-grade glioma and fifteen patients diagnosed as solitary metastases,measuring the SIs and ADC value in regions of tumor, peritumoral edemaand the Contralateral normal brain tissues.Results:1、There were significant difference of SIs in the regions oftumor between high-grade gliomas and solitary metastases with threedifferent b-values. The optimal b-value to differentiate gliomas from solitarymetastases in the region of tumor is5000s/mm~2.when b-value is5000s/mm~2，the optimal cutoff to differential diagnosis is226.4，and the Sensitivity,specificity, positive predictive value, negative predictive value are86.7%，56%，54.2%，87.5%，respectively.2、There were significant difference of ADC in the regions of peritumoraledema between high-grade gliomas and solitary metastases with threedifferent b-values. The optimal b-value to differentiate high-grade gliomasfrom solitary metastases in the region of peritumoral edema is1000s/mm~2.when b-value is1000s/mm~2，the area under ROC is0.988,the optimalcutoff to differential diagnosis is1.40×10-3mm~2/s，and the sensitivity,specificity, positive predictive value, negative predictive value are100％,88％,79.0％，100％,respectively.Conclusion: The SIs of b=5000s/mm~2is most useful to differentiate theregion of tumor in high-grade glioma from that of solitary metastases, whilethe ADC of b=1000s/mm~2is most useful to differentiate the region ofperitumoral edema in glioma from that of solitary metastases.