MR evaluation of the parotid gland using STIR and Gadolinium-enhanced imaging

Abstract

The purpose of this study was to determine the efficiency of the STIR sequence in teh pre-operative assessment of salivary gland lesions, and to evaluate whether administration of intravenous contrast medium provided any additonal information. Nineteen patients with presumed parotid lesions were imaged using T₁-weighted soin-echo and STIR sequences and nine patients also had Gadolinium-DTPA (Gd-DTPA) enhancement. The pathological nature of all lesions was confirmed by cytological or histological examination. T₁-weighted spin-echo images were most useful for visualising anatomical structures and identifying the course of the facial nerve. Internal strcuture of tumours was best displayed with gladolinium enhanced images. Margination and conspicuity of lesions was optimal with STIR, which also achieved a minimal resolution of lesions of 4 × 6 mm diameter. Gd-DTPA enhancement of small lesions was sometimes misleading as they became obscured by surrounding enhancing glandular tissue or overlying fat. It is concluded that the combination is adequate to display anatomy and pathology with accuracy in both extensive ans subtle salivary gland disease. Gd-DTPA did not add to the diagnostic information already obtained by T1 and STIR imaging despite clearer demonstration of tumour architecture.