Value of diffusion tensor imaging in differentiating malignant from benign parotid gland tumors

To evaluate whether diffusion tensor imaging (DTI) can be used to differentiate malignant parotid gland tumors from the benign ones.

The study population comprised 59 parotid gland tumors (24 Warthin's tumors, 19 pleomorphic adenomas, seven other benign tumors, and nine malignant tumors). Single-shot echo-planar DTI was performed with motion-probing gradients along 30 noncollinear directions (b=1000s/mm²) at 3.0T. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values for benign and malignant tumors were compared using the Mann-Whitney U test. Receiver-operating characteristic (ROC) curve analysis was performed to assess the ability of the ADC and FA values to differentiate malignant tumors from the benign ones.

ADC values showed no significant difference between malignant (0.93±0.21×10^-3mm²/s) and benign tumors (1.19±0.50×10^-3mm²/s) (p=0.225). FA values of malignant tumors were significantly higher than those of benign tumors (0.26±0.06 vs. 0.17±0.05, p<0.001). The area under the ROC curve of FA was significantly greater than that under the curve of ADC (0.884 vs. 0.628, p=0.010).

DTI, particularly FA, can help differentiate malignant parotid gland tumors from the benign ones.