Combined role of spectral Doppler and diffusion-weighted MRI in the differentiation between benign and malignant masses of major salivary glands: a prospective cross-sectional study

Abstract Background Preoperative differentiation between benign and malignant salivary gland tumors is challenging but yet necessary. When the use of histopathological diagnosis, as a preoperative diagnostic tool, is invasive and time consuming manner, we tried in this study to evaluate the reliability and significance of multiple radiological tools, namely MRI with diffusion and ADC mapping in addition to spectral Doppler parameters, in differentiating benign and malignant salivary gland tumors in comparison with histopathological findings. Results Our study involved 28 patients, histopathological analysis demonstrated that the majority of lesions were benign, accounting for 64.3% ( n = 18) of the cases, while malignant lesions were representing 35.7% ( n = 10). The mean resistive index (RI) of the malignant lesions as well had a significantly higher level than the benign lesions (0.81 ± 0.17 vs 0.65 ± 0.09, respectively, p = (0.002); the best cutoff value was 0.76 (80% sensitivity, 88.9% specificity. AUC 0.82). The mean pulsatility index PI had also shown a significant higher level in malignant lesions than in benign lesions (1.52 ± 0.28 vs 1.25 ± 0.29, respectively, p = 0.027); the best cutoff value was 1.28 (80% sensitivity, 77.8% specificity, AUC 0.79). The mean PSV of malignant lesions was 49.8 cm/sec ± 22.72(SD) while the mean PSV of benign lesions was 30.39 cm/sec ± 13.51(SD). The best cutoff value of PSV in distinguishing benign from malignant lesions was 34.5 cm/s which had 80% sensitivity, 72.2% specificity with the area under the curve was 0.77.There was a strong statically significant difference of the mean ADC value between benign and malignant lesions (1.23 × 10 –3 ± 0.36 × 10 –3 mm 2 /sec vs 0.84 × 10 –3 ± 0.39 × 10 –3 mm 2 /sec p = 0.015), with the best cutoff value of ADC was 0.79 × 10 –3 mm 2 /sec, which had 70% sensitivity, 88.9% specificity, the AUC was 0.79. Conclusion Both ADC and spectral Doppler showed strong diagnostic performance in distinguishing benign from malignant salivary gland tumors. Combining ADC with the best performing spectral Doppler parameters improved overall accuracy, while incorporating all of spectral Doppler parameters achieved perfect classification in our cohort.