Susceptibility weighted imaging improved diagnostic accuracy of magnetic resonance in characterization of parotid gland lesions

Objective: The purpose of this study was to clarify the diagnostic value of susceptibility weighted imaging (SWI) for distinguishing malignant from benign parotid gland lesions by Magnetic Resonance. Methods: This research prospectively collected the preoperative SWI findings of 41 patients including 12 malignant and 29 benign parotid gland lesions which were confirmed by surgical pathology later. The venous distribution, the maximum diameter of veins (dv-max), the degree of intralesional susceptibility signal (ITSS) and the ITSS per unit area (N/SITSS) were further analyzed with SPSS 16.0 software. Result: The venous distribution (P<0.01), the dv-max (P<0.01), and the ITSS grading (P<0.01) of parotid gland lesions were significantly different between malignant and benign lesions, while N/SITSS (P=0.367) was statistically insignificant. When the Youden index reached the highest point, the optimum thresholds of dv-max was 1.8 mm and ITSS grading was greater or equal to 2. The corresponding areas under the ROC curve (AUC) were 0.924 and 0.856 respectively. Conclusion: The results provided evidence that imaging features of SWI may be helpful in distinguishing malignant from benign parotid gland lesions and worth to be generalized in parotid gland MR scanning.