颞骨原发性恶性肿瘤颅神经侵犯的CT与MR影像学评估

目的 探讨颞骨原发恶性肿瘤颅神经侵犯的CT与MR影像学表现。方法 回顾性分析2010年1月-2018年12月中山大学附属第一医院颞骨原发性恶性肿瘤中合并颅神经侵犯的23例患者的CT、MR影像学资料。其中男15例、女8例,年龄3~80岁;出现颅神经功能障碍17例,包括面神经受累症状者15例,外展神经功能障碍者2例。观察颞骨恶性肿瘤神经侵犯的部位、神经根穿行孔道及神经根的形态、信号及强化等颅神经受侵的CT、MR表现,及其与临床症状、手术病理结果的关系。结果 CT、MRI显示颅神经受侵23例,其中面神经受侵22例,三叉神经受侵5例,展神经、舌咽神经、迷走神经受侵各2例,听神经、副神经、舌下神经受侵各1例。颅神经受侵征象:CT显示面神经管扩大破坏22例,圆孔、卵圆孔骨壁、岩尖三叉神经压迹破坏各2例,颈静脉孔、舌下神经管破坏各1例;MRI显示颅神经增粗、强化8例,神经根干与周围软组织强化影紧贴但未完全包绕3例,神经被肿瘤包绕14例。23例CT、MRI显示的神经受侵患者中出现相应神经症状者17例,占73.9%。同时行CT及MRI检查的16例患者中,CT和MRI影像显示的受累神经分别为19、23根,CT、MRI诊断与临床手术病理一致分别为18、22根,其诊断符合率分别为81.8%(18/22)、95.7%(22/23)。结论 颞骨恶性肿瘤容易出现颅神经侵犯,且以面神经受侵最常见。颅神经受侵CT表现为神经穿行孔道破坏,MRI可直接显示神经增粗、异常强化,神经紧贴软组织影或神经直接被肿瘤包绕。结合CT和MRI的影像评估可以全面精准显示颅神经浸润情况,且MR较CT更为灵敏。

CT and MRI evaluation of cranial nerve invasion in temporal primary malignant tumors

Objective This study aimed to investigate the CT and MR findings of cranial nerve infiltration in malignant tumors of the temporal bone. Methods The CT and MR manifestations of 23 patients with cranial nerve invasion in the temporal bone malignant tumors were retrospectively analyzed. The participants were from the First Affiliated Hospital of Sun Yat-sen University from January 2010 to December 2018 and comprised 15 males and 8 females with ages ranging from 3 years old to 80 years old. Seventeen cases of neurological dysfunction were studied, including 15 cases of facial nerve involvement symptoms and two cases of abducent nerve dysfunction. The appearance of the nerve pathway, the morphology, signal intensity, and enhancement of nerve roots were observed.ResultsCT and MRI showed 23 cases of cranial nerve invasion, including the following: facial nerve invasion in 22 cases; trigeminal nerve invasion in five cases; abductor nerve, glossopharyngeal nerve, and vagus nerve invasion in two cases individually; and auditory, accessory, and hypoglossal nerves in one case individually. The CT images of cranial nerve invasion showed 22 cases of facial nerve tube enlargement and destruction, two cases of round hole, oval hole epiphysis, and apex trigeminal nerve pressure trace destruction, and one case of jugular vein hole and sublingual neural tube destruction. The MRI showed that the cranial nerve roots were thickened and enhanced in 8 cases. The nerve was in contact with the enhanced soft tissue mass but not completely wrapped in three cases. The nerve was surrounded by tumors in 14 cases. Among the 23 patients with nerve invasion, 73.9% showed corresponding neurological symptoms, as revealed by the CT and MRI results. Among the 16 patients subjected to CT and MRI examination, 19 and 23 showed affected nerves, respectively, according to CT and MRI images. The CT and MRI diagnoses were consistent with clinical surgery and pathology with 18 and 22 involved nerves, and the diagnostic coincidence rate was 81.8%(18/22) and 95.7%(22/23), respectively. Conclusions Malignant tumors of the temporal bone were prone to cranial nerve invasion, and the facial nerve was the most common nerve that shows tumor invasion. The CT findings of cranial nerve invasion included bone destruction along the nerve pathway. MRI can directly show the nerve thickening and abnormal enhancement. The soft tissues clinging to the nerve or the nerve were directly surrounded by the tumor. The combination of CT and MRI allowed the comprehensive and accurate evaluation of cranial nerve invasion. MR was more sensitive than CT.