Ultrasound-Guided Fine Needle Aspiration of Major Salivary Gland Masses and Adjacent Lymph Nodes

Performance Evaluation of Ultrasound Images Using Non-Local Means Algorithm with Adaptive Isotropic Search Window for Improved Detection of Salivary Gland Diseases: A Pilot Study

Speckle noise in ultrasound images (UIs) significantly reduces the accuracy of disease diagnosis. The aim of this study was to quantitatively evaluate its feasibility in salivary gland ultrasound imaging by modeling the adaptive non-local means (NLM) algorithm. UIs were obtained using an open-source device provided by SonoSkills and FUJIFILM Healthcare Europe. The adaptive NLM algorithm automates optimization by modeling the isotropic search window, eliminating the need for manual configuration in conventional NLM methods. The coefficient of variation (COV), contrast-to-noise ratio (CNR), and edge rise distance (ERD) were used as quantitative evaluation parameters. UIs of the salivary glands revealed evident visualization of the internal echo shape of the malignant tumor and calcification line using the adaptive NLM algorithm. Improved COV and CNR results (approximately 4.62 and 2.15 times, respectively) compared with noisy images were achieved. Additionally, when the adaptive NLM algorithm was applied to the UIs of patients with salivary gland sialolithiasis, the noisy images and ERD values were calculated almost similarly. In conclusion, this study demonstrated the applicability of the adaptive NLM algorithm in optimizing search window parameters for salivary gland UIs.

Factors Influencing the Outcome of Ultrasound-Guided Fine-Needle Aspiration for Salivary Gland Lesion Diagnosis

OBJECTIVES

This study aimed to assess multiple factors influencing the outcomes of ultrasound (US)-guided fine-needle aspiration (FNA) of salivary gland lesions.

METHODS

From 2008 to 2013, a single radiologist performed US-guided FNA of salivary gland lesions in 243 patients. With the exclusion of pure cysts, poor image quality, and insufficient static image cases, 218 salivary gland lesions in 218 patients were included. The composition, size, location, and vascularity of the lesions were retrospectively investigated on the basis of sonographic findings by the same radiologist. The relationship between sampling adequacy and multiple factors was compared, and the diagnostic accuracy of US-guided FNA of salivary gland lesions was calculated by using the final diagnosis as a reference standard.

RESULTS

The sampling adequacy rate for US-guided FNA of the 218 salivary gland lesions was 96.8% (211 of 218). A significant difference was observed in the composition and vascularity of the lesions (P < .0001), whereas there was no significant difference in the patient age and sex, lesion size, lesion location, and needle size. The rate of inadequate sampling increased in predominantly cystic lesions compared with solid lesions as well as in low-vascularity lesions compared with high-vascularity lesions. Of the 218 lesions, 178 (81.7%) were ultimately diagnosed, and most were benign (162 of 178 [91.0%]). When 3 cases with indeterminate cytologic results were excluded, the sensitivity, specificity, positive and negative predictive values, and accuracy of US-guided FNA of salivary gland lesions were 64.3%, 98.8%, 81.8%, 97.0%, and 96.0%, respectively.

CONCLUSIONS

When using US-guided FNA to diagnose salivary gland lesions, sampling adequacy depends on the composition or vascularity of the lesions.