1152: Color Doppler ultrasound of major salivary glands

Abstract

Color Doppler ultrasound (CDU) is an important imaging technique for analyzing the vascularity of the salivary glands and, in conjunction with gray-scale imaging, can be used to characterize some pathologic conditions. Patients with Sjogren’s syndrome may or may not show parenchymal changes on high-resolution gray-scale ultrasound (US). Gray-scale changes mainly consist of a decrease of parenchymal echogenicity up to a total derangement of parenchymal texture, cyst-like ectasia of peripheral ducts, undefined margins and decreased volume of the gland. CDU show a higher number of color flow signals (CFS) in all heterogeneous glands than in normal glands. The hypervascularity is generally diffuse and can be subjectively graded (e.g., minimal, ± or +; intermediate, ++; or profuse, +++ or ++++). Patients with salivary gland involvement in sarcoidosis had marked parotid swelling and a high grade of parenchymal heterogeneity on US.CDU shows diffuse hypervascularity of the glands similar to that seen in Sjogren’s disease. In chronic sclerosing sialadenitis the most common US appearances are the diffuse cirrhotic-like patterns. The involved gland shows prominent vascularity (++–+++) on CDU, with no mass effect or obvious displacement of the vessels. Both benign and malignant tumors have a higher grade of vascularity than the surrounding salivary parenchyma. Generally, malignant parotid tumors demonstrate a higher degree of tumor vascularization (profuse or intermediate) and higher peak systolic velocities (PSV) than benign tumors. Pleomorphic adenomas are oval hypoechoic lesions. Most had intermediate grade of vascularity and a peripheral basket-like pattern consisting of a fine vascular network surrounding the nodule. Spectral Doppler analysis (SDA) shows a wide range of resistivity index (RI) values (0.6 to 1.0), and a PSV below 50 cm s. Adenolymphomas are well-demarcated tumors, frequently associated with one or more cystic components and posterior enhancement. The larger the lesion, the more predominant the cystic portion. CDU depicts a hilar disposition of CFS with centrifugal distribution through one or more vascular pedicles in a relatively regular pattern. The RI and PSV are not significantly different from those in pleomorphic adenoma. Non-Hodgkin’s lymphomas appeared on US as single or occasionally multiple hypoechoic nodules in the parotid gland, similar to the pleomorphic adenomas, and have feeding and draining vessels that enter or leave and branch into the nodule through a centrally located pedicle, although a real hilum is not visible on gray-scale US. CDU shows profuse (graded +++ or ++++) vascularity. The accuracy of evaluating parotid tumors by gray-scale US has been reported to range from 78% to 90% for benign lesions and lower for malignant tumors (57% to 67%). Estimating the histologic type of a parotid tumor has been reported to have an accuracy of 60%. Fine needle aspiration (FNA) has a limited role in the evaluation of salivary tumors. However, FNA and core needle biopsy are of great aid in the evaluation of inflammatory or tumor-like conditions of salivary glands. CDU-guided biopsy with sampling in different locations of the enlarged salivary gland can provide sufficient diagnostic information from the histologic study to prevent sampling errors of the cytologic study. CDU shows promise as an adjunct to gray-scale US in the differential diagnosis of salivary pathologies.