MR diffusion imaging and ADC measurement in solid and cystic mediastinal masses for differentiating benign from malignant lesions

Abstract

Purpose: The purpose of this study is to evaluate the role of MR diffusion imaging (DWI) and apparent diffusion coefficient (ADC) measurement of solid and cystic mediastinal masses to differentiate benign from malignant lesions. Patients and methods: The study included 52 patients with mediastinal masses underwent conventional MRI and DWI (b value 0, 500 and 1000 s/mm2) examinations with 1.5-T MRI. The signal intensity of the lesions and the ADC values of the solid and cystic lesions were obtained. Statistical analyses were performed with the Mann-Whitney U test (z), Pearson’s chi-square test and receiver operating characteristic (ROC) analysis. Results: 29 lesions were malignant and 23 lesions were benign. The diffusion signal of the malignant masses was significantly higher than benign masses (p = 0.0001), the mean ADC value of benign lesions was higher than that of malignant lesions (p = 0.0001). By ROC analysis, ADC cutoff value of 1.25 × 10−3 mm2/s was considered the threshold value, and the sensitivity and specificity were 94.4% and 86.2%, respectively. There was no statistical difference between the ADC values of the cystic part in either benign or malignant lesions. Conclusion: Diffusion weighted MRI and measurement of ADC value can differentiate between solid benign and malignant mediastinal lesions. Keywords: Mediastinal masses, Mediastinal cystic and solid lesions, Magnetic resonance image, Diffusion-weighted imaging (DWI), Apparent diffusion coefficient (ADC)