Evaluation of pulse sequences used for magnetic resonance sialography

Objectives: To determine the most appropriate sequences for the visualizati on of small parotid ducts in MR sialography. Methods: MR images of a phantom consisting of distilled water in polyethyle ne tubes were obtained with turbo-spin echo (TSE), single-shot turbo-spin e cho (SSTSE), half-fourier acquisition, single-shot turbo-spin echo (HASTE) and turbo gradient-spin echo (TGSE) pulse sequences and compared visually a nd quantitatively. MR sialograms obtained from healthy volunteers and patie nts with Sjogren's syndrome (SS) were obtained using the same four sequence s. Results: In the phantom, TSE images were best and the contrast-noise ratio (CNR) highest. In the volunteers, the main ducts were especially clearly vi sualized with TSE and in SSTSE; however, the majority of secondary and/or t ertiary parotid ducts were not depicted by any of the sequences used. In SS patients, images of small main ducts and small pseudocysts were clearer us ing TSE. However, TSE could not depict the narrow main ducts or peripheral ducts or very small pseudocysts. Conclusions: TSE is considered the most suitable MR sequence for assessing small parotid gland ducts. However, further improvement is needed since it does not always visualize them sufficiently.