Age‐specific size of the normal adenoid pad on magnetic resonance imaging

Conclusions regarding the significance and appearance of the adenoids incidentally noted on magnetic resonance (MR) scans of the brain largely rely on observations of previously published plain film data. In order to determine the age specific appearance of normal adenoid tissue as measured on sagittal T1‐weighted midline MR images, we evaluated 189 patients without a history or clinical evidence of adenoid disease, who were sequentially referred for an MR scan of the brain. The thickness of the adenoid pad was measured to the nearest 1 mm along a line through the pharyngeal tubercle constructed perpendicular to the anterior clival surface. Patients were grouped according to age. Normal subjects demonstrated an age specific variation in the size of the pad with the maximal size being attained in early childhood and then steadily decreasing in later childhood and adulthood (P = 0.0001). The adenoids were largest in the 7–10 years age group (mean, 14.59 mm) and steadily declined to 4.83 mm by 60 years of age. Previous surgery had no effect on adenoid measurement (P = 0.582). Magnetic resonance scans provide an excellent method for assessing the adenoid pad.     

Labyrinthine enhancement on gadolinium-enhanced magnetic resonance imaging in sudden deafness and vertigo: correlation with audiologic and electronystagmographic studies.

Sudden deafness with or without vertigo presents a difficult diagnostic problem. This article describes 12 patients with enhancement of the cochlea and/or vestibule on gadolinium-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (MRI), correlating the enhancement with the auditory and vestibular function. All patients were studied with T2-weighted axial images taken through the whole brain, enhanced 3-mm axial T1-weighted images taken through the temporal bone, and enhanced T1-weighted sagittal images taken through the whole brain. Cochlear enhancement on the side of hearing loss was found in all the patients. The vestibular enhancement correlated with both subjective vestibular symptoms and objective measures of vestibular function on electronystagmography. In 2 patients, the resolution of symptoms 4 to 6 months later correlated with resolution of the enhancement on MRI. No labyrinthine enhancement was seen in a series of 30 control patients studied with the same MRI protocol. Labyrinthine enhancement in patients with auditory and vestibular symptoms is a new finding and is indicative of labyrinthine disease. While abnormalities on electronystagmograms and audiograms are nonspecific and only indicate a sensorineural problem, enhanced MRI may separate patients with retrocochlear lesions, such as acoustic neuromas, from those in whom the abnormal process is in the labyrinth or the brain.     

多模态镜下导航结合术中磁共振辅助下颅底中央区复杂病变的显微外科治疗

目的：探讨多模态镜下导航联合高场强术中磁共振成像系统在颅底中央区复杂病变处理中的应用价值及初步经验。方法：对19例颅底中央区复杂病变应用多模态镜下导航结合术中磁共振辅助进行显微外科治疗,术前将患者影像学信息导入神经导航系统进行三维重建,根据重建影像设计手术切口。手术方式采取经颅入路和经颅外人路,后者包括经口鼻蝶入路和经鼻蝶人路。术中将影像学二维／三维图像投射到术野中,指导手术操作,术中磁共振扫描判断肿瘤切除程度,同时更新导航资料,制定下一步处理计划。结果：镜下导航所示位置与实际情况基本一致。术中MRI扫描1-2次,14例发现肿瘤全切,5例残留,其中2例根据术中扫描更新导航资料并进一步手术切除,未发生与术中MRI相关的并发症或安全事故。结论：应用显微镜下导航技术联合术中磁共振辅助,为手术中实时判断肿瘤切除程度及其他可能发生的意外提供了客观依据,提高了肿瘤显微手术切除程度和手术安全性。     

Cine magnetic resonance imaging: evaluation of persistent airway obstruction after tonsil and adenoidectomy in children with Down syndrome

OBJECTIVE/HYPOTHESIS: Although usually successful, not all obstructive sleep apnea is cured by removal of the tonsils and adenoids (T&A). This is particularly true in children with Down syndrome and craniofacial anomalies. This is because of the multiple levels of obstruction in their airways, with obstruction present not only at the level of the tonsils and adenoids but also from base of tongue obstruction, soft palate collapse, and hypopharyngeal collapse. The cine magnetic resonance image (MRI) is useful in evaluating the upper airway in those patients who have not achieved a normal polysomnogram after T&A surgery. STUDY DESIGN: Prospective case series. METHODS: Fifteen children with Down syndrome who had previously undergone a T&A but continued to have abnormal postoperative polysomnograms underwent a cine MRI with fast gradient cine MRI images. RESULTS: The cine MRI identified different areas and levels of obstruction that ultimately affected the children's treatment courses. Recurrent adenoid tissue, glossoptosis, soft palate collapse, hypopharyngeal collapse, and enlarged lingual tonsils were identified. The results as well as several illustrative cases are presented. CONCLUSION: Cine MRI evaluates upper airway obstruction in children who may have multiple sources of obstruction causing their obstructive sleep apnea. This is particularly helpful in children with Down syndrome and craniofacial anomalies. This technology is useful in all children with complex upper airway obstruction.     

1例耳蜗前庭神经畸形患者耳蜗植入术前的功能性磁共振评估并文献复习

目的:探讨功能性磁共振(fMRI)评价耳蜗前庭神经畸形患者是否有人工耳蜗植入指征的可能性。方法:对1例15岁双侧耳聋患者,在人工耳蜗植入前进行听力学、影像学检查及fMRI综合评估。结果:纯音测听和听觉脑干反应显示患者为双侧极重度感音神经性聋,瞬态诱发性耳声发射双侧均未引出。颞骨薄层CT显示内耳畸形(不全分隔Ⅰ型),MRI斜矢状位重建显示耳蜗前庭神经畸形。fMRI显示左耳给声,1000Hz100dBHL,右侧听皮层被激活;右耳给声,双侧听皮层均未见激活。左侧人工耳蜗植入术后1个月开机,患者对声音有反应。结论:结合听力学和影像学检查,fMRI可评估人工耳蜗植入候选者,尤其是在影像学检查显示患者耳蜗前庭神经发育畸形时,更是一种有效的评估方法。     

Osteoplastic frontal sinus surgery with fat obliteration: technique and long-term results using magnetic resonance imaging in 82 operations

OBJECTIVE: To evaluate the intraoperative and late complications of osteoplastic sinus surgery with fat obliteration with long-term magnetic resonance imaging (MRI) follow-up. METHODS: The operative records of all patients who underwent osteoplastic frontal sinus surgery with fat obliteration between January 1, 1986 and December 31, 1997 were reviewed and the postoperative clinical course and magnetic resonance imaging (MRI) scans were analyzed if available. MRI analyses revealed that changes in the distribution of fatty and fibrous tissue, the development of necrosis or oil cysts, recurrences, inflammatory complications, and mucoceles were time-dependent occurrences. RESULTS: Eighty-two operative records were evaluated and 59 patients were followed 1 to 12 years after surgery. Eighty-six MRI scans in 51 patients were available for analysis. The most frequent intraoperative complications were exposure of orbital fat (19.5%), unintentional fracture of the anterior wall (19.5%), incorrect placement of the anterior wall (17%), and dural injury (9.8%). Persistent changes of the frontal contour (embossment, depression) occurred in 10.2% and the esthetic result was unfavorable in 5.1% of the cases. Mucoceles could be detected in 5 of 51 cases (9.8%). The amount of adipose tissue detectable in the last scan was less than 20% in the majority of cases (53%), and more than 60% in only 18% of the cases. The amount of adipose tissue decreased significantly with time (the median half-life was 15.4 mo). CONCLUSIONS: Osteoplastic frontal sinus surgery with fat obliteration is very useful and successful in patients in whom the frontal sinus is not accessible via an endonasal approach or the natural drainage cannot be reestablished. MRI is currently the most valuable diagnostic tool to evaluate the frontal sinus after obliteration with adipose tissue. The method has some limitations with regard to detection of small recurrent mucoceles and differentiating vital adipose tissue from fat necroses in the form of oil cysts. In these difficult cases, long-term MRI follow-up is necessary.