[Evaluation of soft tissue lesions affecting the masticator space with dynamic contrast enhanced MRI].

OBJECTIVE:To determine the characteristics and diagnostic value of dynamic contrast enhanced MRI (DCE-MRI) in differentiating benign soft tissue lesions from malignant tumors affecting the masticator space (MS). METHODS:Prior to managements, conventional MRI and DCE-MRI were performed in 53 patients who suffered from primary or secondary soft tissue lesions affecting the MS. The time to peak (TTP), relative maximum enhancement (RME) and relative washout ratio (RWO) were separately calculated. RESULTS:Mean TTP of benign and malignant lesions were (130.3 ± 13.2) and (69.6 ± 6.9) s, respectively. Mean RWO of benign and malignant lesions were (29.7 ± 5.5)% and (8.7 ± 2.1)%, respectively. Malignant lesions had a significantly shorter TTP(P = 0.001) and lower RWO (P = 0.003) than benign lesions. When TTP was less than 92.2 s and RWO less than or equal to 16.0%, malignant tumors were considered. DCE-MRI had a sensitivity of 72.3%, specificity of 93.5%, accuracy of 84.9%, positive predictive value of 88.9%, and negative predictive value of 82.9%. CONCLUSIONS:As a non-invasive imaging technique, DCE-MRI is valuable to differentiate benign soft tissue lesions from malignant tumors affecting the MS.