Apparent Diffusion Coefficient Histogram Of MR Diffusion Weighted Imaging In The Differential Diagnosis Between High-grade Gliomas And Brain Metastases

Objective To investigate the value of apparent diffusion coefficient histogram in the differentiation of high-grade gliomas and brain metastases.Materials and Methods The conventional MR imaging,contrast –enhanced MR imaging and diffusion weighted imaging were performed in 13 patients with high-grade gliomas and 20 patients with brain metastases before any antineoplastic therapy.With reference of T2 WI,area of tumor was defined on each section of axial ADC maps to generate ADC histogram by MATLAB.Histogram-derived ADC parameters(ADCmean,ADCmax,ADCmin,ADCmedian,kurtosis,skewness,standard deviation,range and every 5% ADC value of the histogram)were analyzed between high-grade gliomas and brain metastases.It was defined as significant difference when P value was lower than 0.05.Receiver operating characteristic(ROC)analyses were performed determine the diagnostic efficiency and optimal thresholds for differentiating the high-grade gliomas from brain metastases by meaningful parameters.Results ADC histograms of high-grade gliomas and brain metastases were all skewness distribution.Most high-grade gliomas were positive skewness distribution,and shows a leptokurtic,the tail on the right is longer than left.Most brain metastases were negative skewness distribution,and shows a platykurtic,the tail on the left is longer than right.Kortosis,skewness,ADCmax,ADCmin of high-grade gliomas were 4.40±2.08,0.87±0.72,(2.63±0.44)×10-3mm2/s,(2.14±0.52)× 10-3mm2/s,and which of brain metastases were 3.12±1.44,0.41±0.55,(2.17±0.65)×10-3mm2/s,(1.55±0.69)×10-3mm2/s,lower than the value of high-grade gliomas(P<0.05).AUC,sensitivity,specificity and optimal threshold of kurtosis were 0.71,76.92%,60%,2.87;AUC,sensitivity,specificity and optimal threshold of skewness were 0.72,53.85%,90.00%,1.11;AUC,sensitivity,specificity and optimal threshold of range were 0.76,84.62%,65.00%,1.70×10-3mm2/s;AUC,sensitivity,specificity and optimal threshold of ADCmax were 0.70×10-3mm2/s,76.92%,60.00%,2.20×10-3mm2/s.The skewness of ADC is highest specificity,range of ADC histogram is highest AUC and sensitivity,the joint specificity of skewness and range is 58.50%,the joint sensitivity is 92.90%.Conclusion ADC histogram can become a new method to differentiate high-grade gliomas from brain metastases,and it performed better than conventional ADCs.