T2WI maximum tumor level histogram for differentiating parotid pleomorphic adenoma and malignant tumor / 中国介入影像与治疗学

ABSTRACT

Objective: To assess the value of T2WI maximum tumor level histogram in differentiating pleomorphic adenoma from malignant tumors of parotid gland. Methods: MRI of 64 patients with parotid tumors, including 41 cases of pleomorphic adenomas and 23 cases of malignant tumors confirmed by pathology were analyzed retrospectively. Mazda software was used to select ROIs in the maximum tumor level image on axial T2WI. Gray histogram analysis was carried out to obtain 9 characteristic parameters, including mean, variance, kurtosis, skewness, first percentile (perc 1%), tenth percentile (perc 10%), fiftieth percentile (perc 50%), ninetieth percentile (perc 90%) and ninety-ninth percentile (perc 99%). Statistical analysis was performed to compare the characteristic parameters of histogram between pleomorphic adenoma and malignant tumors. ROC curve was drawn to evaluate the effectiveness of the characteristic parameters of histogram in tumors differentiating. Results: Among 9 characteristic parameters of histogram, perc 1% and perc 10% had statistical differences between pleomorphic adenoma and malignant tumors (both P<0.05). Both of perc 1% and perc 10% of pleomorphic adenoma were significantly higher than those of malignant tumors. ROC curve analysis showed that perc 10% was the most effective parameter for differential diagnosis. The AUC was 0.70 (P=0.01), and the optimal critical value was 76.00. The sensitivity and specificity was 66.70% and 60.00%, respectively. Besides, the AUC, optimal critical value, sensitivity and specificity of perc 1% was 0.67 (P=0.04), 46.50, 63.90% and 60.00%, respectively. Conclusion: T2WI maximum tumor level histogram can be used as an important method to differentiate pleomorphic adenoma from malignant tumors of parotid gland before operation, which can provide valuable references for clinic.