Contrast-enhanced ultrasound for monitoring effects of extracorporeal shock wave sialolithotripsy in sialolithiasis

Ultrasound in Inflammatory and Obstructive Salivary Gland Diseases: Own Experiences and a Review of the Literature

Background: Ultrasound is established as a diagnostic tool in salivary glands for obstructive diseases such as sialolithiasis and tumors. Concerning inflammatory diseases and in non-sialolithiasis-caused obstruction, much fewer data are available. In recent years, technical development has allowed a better assessment of the gland parenchyma, and knowledge about intraductal pathologies has increased considerably, which has provided new insights and a new interpretation of ultrasound findings. Objectives: To provide a comprehensive review of the literature that includes our own experiences and to point out the state of the art in ultrasound in the diagnostics of inflammatory and obstructive salivary gland diseases, taking adequate techniques and recent technical developments into consideration. Data sources and study eligibility criteria: A systematic literature search was performed in Pubmed using various specific key words. Results: According to the literature results, including our own experiences, ultrasound is of value in up to >90% of cases presenting with inflammatory and/or obstructive diseases. Technical developments (e.g., elastography) and the application of modified ultrasound techniques (e.g., transoral ultrasound) have contributed to these results. Today, ultrasound is considered a first-line diagnostic tool in these diseases. However, in some inflammatory diseases, the final diagnosis can be made only after inclusion of the anamnesis, clinical symptoms, serologic blood tests, or histopathologic investigation. Conclusions: Ultrasound can be considered as a first-line diagnostic tool in obstructive and inflammatory salivary gland diseases. In obstructive diseases, it may be sufficient for diagnostics in >90% of cases. In inflammatory diseases, ultrasound is at least an excellent screening method and can be used to establish the diagnosis in cases of an early suspicion. In all diseases ultrasound can contribute to better management and can be used for monitoring during follow-up.

Salivary lithotripsy in the era of sialendoscopy

The traditional management of obstructive salivary disorders has been replaced by minimally-invasive gland-preserving techniques including shock-wave lithotripsy, sialendoscopy, interventional radiology and endoscopically video-assisted trans-oral and cervical stone retrieval, of which sialendoscopy is considered to be the method of first choice. Primary endoscopically controlled stone extraction without prior fragmentation is only possible in 15-20% of cases; in more than 80%, fragmentation is necessary because of the size, impactation and location of the stone, or an alternative treatment such as transoral duct surgery or combined approaches are required. Moreover, about 10-20% of all stones cannot be adequately accessed by means of a sialendoscope or any alternative surgical method and, in such cases, extra-corporeal shock wave lithotripsy (ESWL) is the treatment of choice. However, in endoscopically accessible stones, ESWL is being gradually replaced by endoscopically assisted intra-corporeal techniques, including endoscopically guided laser and pneumatic intracorporeal lithotripsy. We describe the currently most widely used techniques for salivary lithotripsy, including ESWL, and endoscopically guided laser, electrohydraulic, electrokinetic and pneumatic intra-corporeal lithotripsy, and discuss their indications given the widespread use of advanced rehabilitative sialendoscopy and combined therapeutic approaches.

Dynamic contrast-enhanced ultrasound for differential diagnosis of submandibular gland disease

Intensity-time gradients (ITGs) of contrast-enhanced ultrasound (CEUS) can be used for non-invasive monitoring of gland-preserving treatment effects in sialolithiasis-related chronic sialadenitis as well as for imaging vascularization in tumors. The aim of this clinical trial was to evaluate feasibility to distinguish different entities of submandibular gland disease including inflammatory alterations of the submandibular gland as well as benign and malignant tumors. In this prospective clinical study, ITGs in 30 patients with sialolithiasis-related chronic sialadenitis or an unilateral submandibular mass and 18 disease-free submandibular gland controls were quantitatively analyzed by CEUS using the contrast agent SonoVue. In addition, clinical complaints according to visual analog scales (VAS) were documented. VAS data documented significantly less complaints only in benign tumors compared with the other pathologies of the submandibular gland. In parallel, CEUS-derived ITGs revealed significantly reduced ITGs only in benign tumors (n = 5) compared to the controls (n = 18). Despite of comparably reduced wash-in velocities in malignant lesions (n = 3) statistical significance was not reached. Chronic sialadenitis (n = 18) and its sclerosing variant (Küttner tumor, n = 4) revealed comparable ITGs as controls. Tumors of the submandibular gland present with reduced functional microcirculatory networks comparing with healthy gland controls and chronically inflamed submandibular glands. Thus, dynamic CEUS-derived ITGs in combination with conventional clinical measures--for example VAS--appear as a safe and promising strategy for non-invasive diagnostic workup of submandibular lesions and warrant further validation in a larger set of patients.

Validation of contrast-enhanced ultrasound-derived intensity-time gradients in submandibular gland sialolithotomy patients

Contrast-enhanced ultrasound (CE-US)-derived intensity-time gradients (ITGs) can be used for noninvasive monitoring of extracorporeal shock wave sialolithotripsy effects in chronic sialolithiasis-related sialadenitis. Aim of this trial was to further validate CE-US as an independent and quantitative diagnostic tool for sialolithotomy efficacy. In this prospective clinical phase II evidence level c study perfusion in patients (n = 10) with unilateral sialolithiasis of the submandibular gland was quantitatively analyzed by CEUS before and after sialolithotomy comparing with the contralateral disease-free gland. A visual analog scale (VAS) scoring clinical complaints was correlated with CE-US-derived ITGs. Furthermore, ITG ratios reflecting values from the contralateral side and the diseased side were calculated. VAS documented significantly reduced clinical complaints after sialolithotomy indicative of a successful treatment. VAS data significantly correlated with CE-US-derived ITGs. In addition, ITG ratios were significantly increased after sialolithotomy. In conclusion, CE-US-derived ITGs and ITG ratios appear as independent and valid quantitative parameters of sialolithotomy efficacy.