Multimodal ultrasonographic characterisation of parotid gland lesions--a pilot study

Lesions of the major salivary glands represent a heterogeneous group comprising infectious, autoimmune, and neoplastic disorders. The reliable pre-operative assessment of the lesional dignity might reduce patient's morbidity preventing re-surgery. To date, there exists no imaging technique which reliably distinguishes tumour entities.

35 parotid lesions were analysed in this study. B-mode ultrasound, colour duplex imaging and contrast enhanced ultrasound were applied for all patients. After fractionated boli of 4.8 ml SonoVue® perfusion kinetics, time to peak (TP) and mean transit time (MTT), were analysed for intraparotideal lesion and were normalised by circumjacent parotid tissue. Ultrasonographic data was structured in a multimodal diagnostic pathway.

B-mode ultrasound identifies six lymphoepithelial lesions due to Sjoegren's syndrome (p: 0.0001). CDS further differentiates hypovascularised pleomorphic adenoma from hypervascularised Warthin's tumours, monomorphic adenomas, and carcinomas (p<0.0001). Application of CEUS detected Warthin's tumours being significantly hypervascularised compared to monomorphic adenomas (MTT, p<0.05) and carcinomas (MTT, p<0.02).

A multimodal diagnostic pathway unifies different ultrasonographic techniques and identifies pleomorphic adenomas, Warthin's tumours and carcinomas with sensitivities of 100%. Further studies have to be performed to validate this diagnostic approach and to specify monomorphic adenomas.