3 T MR三维稳态进动快速成像序列显示腮腺肿瘤及其与腮腺内面神经和腮腺导管的关系

目的 探讨3 T MR三维稳态进动快速成像(3D-FIESTA)序列显示腮腺良性肿瘤及其与腮腺内面神经和腮腺导管关系的价值.方法 对22例腮腺良性肿瘤患者采用8通道头部线圈行3T常规MR序列T_1 WI、T_2 WI及3D-FIESTA序列扫描,并进行图像后处理.腮腺良性肿瘤与腮腺内面神经和腮腺导管的关系与手术结果相对照.结果 不同类型的腮腺良性肿瘤3 T MRI表现具有各自的特点.22例腮腺肿瘤在T_1WI主显示为低信号,在T_2WI上为高信号,其显示结果分别为21、22例;3D-FIESTA序列上则根据腮腺肿瘤类型的不同表现为低信号(10例)或高信号(12例)为主.腮腺内面神经主要分支在T_1WI、T_2WI及3D-FIESTA序列图像均显示为线样低信号结构,T_1、T_2WI对面神经主干的显示分别为16、18例;而3D-FIESTA对面神经主干、颞面支、颈面支的显示分别为22、21、22例.腮腺导管及其主要分支在T_1WI上呈线条低信号,T_2WI及3D-FIESTA序列图像显示为条状高信号结构,其显示分别为14、20、22例.与手术结果相对照,腮腺内面神经主干的显示结果为22例;腮腺主导管20例与3D-FIESTA序列的显示情况相一致,另2例因肿瘤推压移位,手术解剖未发现.结论 3 T MR 3D-FIESTA序列可以正确显示腮腺内面神经和腮腺导管及其与腮腺肿瘤的关系,对腮腺肿瘤手术计划的制定有重要的应用价值.

3 T MR 3D fast imaging employing steady state acquisition demonstrating branches of intraparotid facial nerve, parotid duct, and relation with parotid tumors

Objective To investigate the usefulness of 3 T MRI 3D-FIESTA in the evaluation of the intraparotid components of the facial nerve and parotid duct, and compare them with surgical findings. Methods Twenty-two cases with parotid benign tumors were scanned with conventional and 3D-FIESTA sequences on 3 T MRI scanner. Postprocessed multiplanar images were obtained with the workstation. Parotid ducts and facial nerves and tumors were identified on these images. The relationship of the tumors to the facial nerves and Parotid ducts was confirmed at surgery. Results Various types of parotid benign tumors had their characteristics on 3 T MR imaging. Parotid benign tumors mainly showed hypo-intensity on T_1WI in 21 cases, and hyper-intensity on T_2WI in 22 cases. But on 3D-FIESTA images, they appeared hypo-intensity (10 cases) or high intensity (12 cases) due to different types. Facial nerves in parotid appeared as linear structures with hypo-inteusity. The indication of the main trunks were 16 and 18 cases for T_1WI and T_2WI images, while on 3D-FIESTA images, the main trunks and cervicofacial and temporofacial divisions of the facial nerves were found in 22, 21,22 cases. Parotid ducts appeared as structures with hypo-intensity on T_1WI and hyper-intensity on multiplanar images (14, 20, 22 cases). Compared with surgical results, the main trunks of the facial nerve were correctly showed by 3D-FIESTA images in 20 cases. However, in 2 cases they were not located in the operation because of shifting. Conclusion 3 T MR 3D-FIESTA imaging could depict the extracranial facial nerve and the parotid duct in the parotid gland, which is useful for preoperative evaluation of parotid gland tumors.