Value of high-resolution MR scan using micro-surface coil in the diagnosis of primary facial nerve tumors
Dai Qunyao1, Hong Guixun2, Yang Zhiyun2
1 Department of Medical Imaging, Peking University Shenzhen Hospital, Shenzhen 518036, China;
2 Department of Radiology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
Abstract:Objective To investigate the clinical value of high-resolution MR scan using micro-surface coil in the diagnosis of primary facial nerve tumors. Methods Retrospective study. Sixteen cases of primary facial nerve tumors [11 males and 5 females, aged 15-56 (34.9±11.7) years] confirmed by surgery or biopsy in the Department of Otorhinolaryngology, the First Affiliated Hospital of Sun Yat-sen University from May 2015 to October 2019 were collected. Before operation, all patients underwent facial high-resolution scan using micro-surface coil and curved planar reformation of facial nerves (Method A). Conventional MR plain and enhanced scans using head coil (Method B) were also performed. (1) The location, involved range, shape, growth pattern, and signal characteristics of tumors on images of these two methods were analyzed, and the maximum diameter was compared by paired t-test. (2) The characteristic “entering and exiting facial nerve sign”, which reflected the relationship between tumors and facial nerves, was taken as the MRI diagnostic standard of facial nerve tumors, and pathological diagnosis was taken as the gold standard. The diagnostic accuracy of the two methods was compared by paired Chi-square test. Results (1) Methods A and B showed consistency in displaying the location, involved range, and shape of the tumors. However, compared with Method B, Method A displayed the range more intuitively. Nine tumors were located on the left side and seven on the right side. All tumors involved two or more segments of the facial nerve. The tumor center of 1 case was located in the internal auditory canal, 1 in the labyrinthine segment, 6 in the geniculate ganglion, 5 in the tympanic cavity, 1 in the mastoid region, and 2 in the parotid gland area. Seven cases showed irregular, lobulated, or cauliflower shape, 5 showed round shape, and 4 showed mushroom shape. (2) The maximum diameter of tumors in Method A was 8-33.5 (18.9±7.9) mm, and that in Method B was 8.5-32.5 (18.8±7.85) mm. No significant difference was observed between the two methods (t=0.951, P>0.05). (3) In Method A, the signal of tumors was similar to that of normal nerves. In Method B, the tumors showed mainly or slight hypointensity on T1WI and hyperintensity or slight hyperintensity on T2WI. Tumors with cystic changes showed heterogeneous signal in both methods. (4) All 16 cases in Method A showed “entering and exiting facial nerve sign,” whereas only four cases showed this sign in Method B. The diagnostic accuracy was 16/16 and 4/16, respectively, and the difference between the two methods was statistically significant (P=0.000). Conclusions High-resolution MR imaging using micro-surface coil combined with curved planar reformation can improve the ability of showing the relationship between tumors and facial nerves, thereby improving the diagnostic accuracy of primary facial nerve tumors. The “entering and exiting facial nerve sign” is of great value to the MRI diagnosis.
戴群瑶, 洪桂洵, 杨智云. 微小表面线圈高分辨MR扫描在原发性面神经肿瘤诊断中的应用价值[J]. 中华解剖与临床杂志, 2020, 25(6): 617-621.
Dai Qunyao, Hong Guixun, Yang Zhiyun. Value of high-resolution MR scan using micro-surface coil in the diagnosis of primary facial nerve tumors. Chinese Journal of Anatomy and Clinics, 2020, 25(6): 617-621.
McRackan TR, Wilkinson EP, Rivas A. Primary tumors of the facial nerve[J]. Otolaryngol Clin North Am, 2015, 48(3): 491-500. DOI:10.1016/j.otc.2015.02.008.
[3]
Lee JD, Lee WS.Surgical findings to differentiate between facial nerve schwannoma and vestibular schwannoma[J]. Clin Exp Otorhinolaryngol, 2014, 7(3): 157-159. DOI:10.3342/ceo.2014.7.3.157.
[4]
Ma Q, Song H, Zhang P, et al.Diagnosis and management of intraparotid facial nerve schwannoma[J]. J Craniomaxillofac Surg, 2010, 38(4): 271-273. DOI:10.1016/j.jcms.2009.07.005.
[5]
周宙, 潘碧涛, 李卓浩, 等. 微小表面线圈和3D-PSIF-DWI在面神经腮腺段成像中的初步应用[J]. 临床放射学杂志, 2012, 31(5): 717-720. DOI:10.13437/j.cnki.jcr.2012.05.012.Zhou Z, Pan BB, Li ZH, et al.A preliminary study of displaying facial nerve of intraparotid segment using micro surface coil and 3D PSIF DWI[J]. J Clin Radiol, 2012, 31(5): 717-720. DOI:10.13437/j.cnki.jcr.2012.05.012.
Abreu E, Aubert S, Wavreille G, et al.Peripheral tumor and tumor-like neurogenic lesions[J]. Eur J Radiol, 2013, 82(1): 38-50. DOI:10.1016/j.ejrad.2011.04.036.
[8]
Quesnel AM, Santos F.Evaluation and management of facial nerve schwannoma[J]. Otolaryngol Clin North Am, 2018, 51(6): 1179-1192. DOI:10.1016/j.otc.2018.07.013.
[9]
Aboshanif M, Omi E, Suzuki S, et al.Facial nerve neuroma in the geniculate ganglion extending into the internal auditory canal: a case report[J]. Auris Nasus Larynx, 2018, 45(3): 648-652. DOI:10.1016/j.anl.2017.09.010.
Xu F, Pan S, Alonso F, et al.Intracranial facial nerve schwannomas: current management and review of literature[J]. World Neurosurg, 2017, 100: 444-449. DOI:10.1016/j.wneu.2016.09.082.
[12]
Matsushima K, Kohno M, Izawa H, et al.Middle fossa approach for facial nerve schwannoma aiming for functional improvement: 2-dimensional operative video[J]. Oper Neurosurg (Hagerstown), 2020, 18(5): E167-E168. DOI:10.1093/ons/opz178.
[13]
Park SH, Kim J, Moon IS, et al.The best candidates for nerve-sparing stripping surgery for facial nerve schwannoma[J]. Laryngoscope, 2014, 124(11): 2610-2615. DOI:10.1002/lary.24814.
[14]
Sayegh ET, Kaur G, Ivan ME, et al.Facial neuroma masquerading as acoustic neuroma[J]. J Clin Neurosci, 2014, 21(10): 1817-1818. DOI:10.1016/j.jocn.2013.12.029.
Shimizu K, Iwai H, Ikeda K, et al.Intraparotid facial nerve schwannoma: a report of five cases and an analysis of MR imaging results[J]. AJNR Am J Neuroradiol, 2005, 26(6): 1328-1330.
[17]
Ciobanu L, Seeber DA, Pennington CH.3D MR microscopy with resolution 3.7 μm by 3.3 μm by 3.3 μm[J]. J Magn Reson, 2002, 158(1-2): 178-182. DOI:10.1016/s1090-7807(02)00071-x.
[18]
鲜军舫, 王振常, 李强, 等. 面神经瘤的影像学研究[J]. 中华放射学杂志, 2001, 35(7): 487-491. DOI:10.3760/j.issn:1005-1201.2001.07.002.Xian JF, Wang ZC, Li Q, et al.Imaging investigation of facial neuroma[J]. Chin J Radiol, 2001, 35(7): 487-491. DOI:10.3760/j.issn:1005-1201.2001.07.002.
[19]
张骥, 罗道天. 面神经瘤的CT和MRI诊断[J]. 中华放射学杂志, 2001, 35(7): 491-493. DOI:10.3760/j.issn:1005-1201.2001.07.003.Zhang J, Luo DT.CT and MRI diagnosis of facial nerve neuroma[J]. Chin J Radiol, 2001, 35(7): 491-493. DOI:10.3760/j.issn:1005-1201.2001.07.003.