A PROSPECTIVE cross-sectional study reports that combining diffusion-weighted MRI with spectral Doppler ultrasound significantly enhances clinicians’ ability to distinguish benign from malignant tumours in the major salivary glands. The findings could help reduce reliance on invasive preoperative procedures such as biopsies, which are often time-consuming and uncomfortable for patients.
The research team evaluated 28 patients presenting with salivary gland masses. Histopathological examination later confirmed that 64.3% of the lesions (18 cases) were benign, while 35.7% (10 cases) were malignant.
Researchers Identify Key Markers to Distinguish Salivary Gland Tumours
Across multiple parameters, malignant tumours showed consistently distinct imaging characteristics. Spectral Doppler ultrasound demonstrated particularly strong discriminatory power. Malignant lesions exhibited significantly higher resistive index (RI) values, averaging 0.81 compared to 0.65 in benign tumours. An RI cutoff of 0.76 yielded an 80% sensitivity and an 88.9% specificity (AUC 0.82), making it the most powerful Doppler marker.
Pulsatility index (PI) also proved valuable: malignant masses showed a mean PI of 1.52 versus 1.25 in benign lesions. A cutoff of 1.28 provided 80% sensitivity and 77.8% specificity (AUC 0.79). Peak systolic velocity (PSV) contributed additional differentiation, with malignant tumours displaying markedly higher flow velocities. A PSV threshold of 34.5 cm/s achieved 80% sensitivity and 72.2% specificity.
Diffusion-weighted MRI further strengthened diagnostic accuracy. Malignant lesions had significantly lower apparent diffusion coefficient (ADC) values, averaging 0.84 × 10⁻³ mm²/s, compared with 1.23 × 10⁻³ mm²/s in benign lesions. An ADC cutoff of 0.79 × 10⁻³ mm²/s yielded 70% sensitivity and 88.9% specificity.
Combined Imaging Approaches Transform Salivary Gland Tumours Evaluation
Crucially, the study found that combining ADC measurements with top-performing Doppler parameters improved diagnostic precision beyond what either modality achieved alone. When all Doppler indices were integrated with MRI findings, the researchers reported perfect classification of tumours within their cohort.
The authors conclude that a multimodal imaging approach may provide a highly reliable, non-invasive alternative to preoperative biopsy, potentially streamlining diagnosis and improving patient care in salivary gland tumour management.
Reference
Mohammad MTA et al. 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. Egypt J Radiol Nucl Med. 2025; 56:230
