Role of diffusion-weighted MRI in evaluation of patients with salivary gland tumors

Abstract

Background and objectives Diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) values give appreciable information about tumor cellularity with tissue contrast between the active and necrotic areas within the tumor. Aim of the work The aim of this study was to investigate the capacity of diffusion MRI to predict benign and malignant salivary gland tumors, using ADC value and DWI. Patients and methods This study included 40 patients (24 male and 16 female). Sixteen patients had malignant lesions and 24 had benign ones. The DWI was obtained with b values including 0 and 800 mm2/s. The ADC was generated by measuring identical images at different b values and represented as ADC map, from which the ADC value was calculated. This was a prospective randomized controlled trial. Informed consent was obtained from parents or guardians. Results The absolute ADC value of lesions was significantly different between benign and malignant salivary gland tumors (P<0.001). The sensitivity of ADC in differentiating benign from malignant lesions in our study was 93.7%, indicating a high true positive rate. Hence, if the average ADC is below 0.85×10−3 mm2/s, there is high probability that the mass will be malignant with high specificity of 95.8%. Results revealed that the mean ADC values of benign and malignant salivary gland tumors were 1.33±0.46×10 and 0.65±0.21×10−3 mm2/s, respectively. The mean ADC value of benign lesions was significantly higher than that of malignant lesions. Conclusion The use of DWI and ADC values can provide better assessment of salivary gland tumors and predict benign and malignant lesions.

Keywords

• diagnostic imaging
• head and neck neoplasms
• salivary glands