以眼科症状首诊的鼻咽癌MRI特征

目的 探讨以眼科症状首诊的鼻咽癌患者的MRI表现.方法 回顾性分析经病理证实的22例鼻咽癌患者Ⅲ、Ⅳ和(或)Ⅵ组颅神经侵犯的临床及MRI表现.结果 22例鼻咽癌患者病变均沿眼运动神经走行分布区浸润扩散.22例患者中复视者14例.发生外展神经、动眼神经和滑车神经不全麻痹者分别为12例(16侧)、6例(7侧)和3例(4侧).MRI表现:海绵窦受累表现为增厚型(8例共10侧)或肿块型(14例共16侧);眶上裂扩大4例4侧,眶上裂软组织信号影9例共10侧;眼外肌受累8例共10侧,表现为眼外肌增粗、周围脂肪间隙模糊伴异常强化;10例动态增强扫描显示鼻咽部病变与海绵窦、眶内病变的动态增强扫描曲线一致,均表现为速升平台型.结论 眼运动神经损害是鼻咽癌的首诊症状之一,应用MR检查可以明确诊断.     

Tentorial enhancement on MR images is a sign of cavernous sinus involvement in patients with sellar tumors

BACKGROUND AND PURPOSE: This study was undertaken to analyze enhancement patterns of the dura around sellar tumors and to compare the results with tumor invasion or compression of the cavernous sinuses. Postoperative enhancement patterns on MR images were compared with preoperative findings. METHODS: Contrast-enhanced coronal and sagittal MR images were examined prospectively in 96 patients with sellar tumors (65 macroadenomas, 15 microadenomas, 14 Rathke cleft cysts, and two chordomas at the sella). All patients underwent surgical treatment, and pre- and postsurgical features on MR images were compared. RESULTS: Presurgical MR images showed dural enhancement in 36.5% of the patients: asymmetric tentorial enhancement in 24 patients, symmetric tentorial enhancement in seven, and sphenoidal ridge or clivus enhancement in four. Asymmetric tentorial enhancement disappeared after surgical decompression in seven patients. For evaluation of cavernous sinus invasion ipsilateral to the enhancement, sensitivity and specificity of the asymmetric tentorial enhancement sign were 81.3% and 86.3%, respectively. Sensitivity and specificity of the sign were 42.9% and 93.6% for cavernous sinus involvement, including compression and invasion. CONCLUSION: Asymmetric tentorial enhancement is a useful sign in the diagnosis of invasion or severe compression of the cavernous sinus by sellar tumor. The sign may represent venous congestion or collateral flow in the tentorium due to obstructed flow in the medial portion of the cavernous sinus.     

CT and angiography of primary extradural juxtasellar tumors

The computed tomographic and angiographic features of 15 histologically proven primary extradural juxtasellar tumors were retrospectively reviewed. Five chordomas were characterized by prominent bone erosion and a significant posterior fossa component. Four trigeminal nerve neuromas each demonstrated bone erosion centered about Meckel's cave and moderate to marked contrast enhancement. Two cavernous sinus meningiomas revealed moderate contrast enhancement, expansion of the cavernous sinus, and moderate angiographic stain. Two cavernous hemangiomas of the cavernous sinus were intensely enhancing and demonstrated angiographic stain. Opacification of the sphenoid sinus with prominent bone destruction and lack of contrast enhancement was characteristic of a sphenoid sinus mucocele. The dural reflection could be directly visualized or indirectly inferred in each case.     

Inflammatory myofibroblastic tumor of the orbit with associated enhancement of the meninges and multiple cranial nerves

Inflammatory myofibroblastic tumor (IMT), Tolosa-Hunt syndrome (THS), and idiopathic hypertrophic pachymeningitis (IHP) seem to be part of a spectrum of disorders that have diverse locations but similar histologic and imaging findings. We report a case of a 50-year-old man presenting with multiple progressive cranial nerves palsies with leptomeningeal cranial nerve enhancement on MRI (II, V1-V3, and X), orbital and infraorbital masses, prominence within the left cavernous sinus, and diffuse dural enhancement. Biopsies of the orbital lesion and infraorbital nerve revealed IMT. The patient's lesions, symptoms, and dural enhancement quickly improved with steroid administration and nearly resolved over multiple subsequent scans over the next few months. This case illustrates a rare case of pseudotumor mimicking a more aggressive appearance that would usually portend a case of malignancy. There is a potential association of IMT, THS, and IHP, which may have existed in a concomitant fashion in this patient. The case also describes the unique finding of enhancement of the cisternal segments of multiple cranial nerves (simulating leptomeningeal malignant involvement), which may be related to inflammatory perineural edema or ischemic neuropathy.     

海绵窦的MRI解剖

为海绵窦解剖的影像学和外科学提供基础资料。方法利用１１具头颅冠状断面层标本,３６例正常头颅冠状面平扫,动态和常规增强ＭＲＩ对照研究了海绵窦的位置,形态和内容。结果海绵窦为中颅凹两层硬脑膜民的硬脑膜窦,颈内动脉和外层神经位于海绵窦内,     

Roentgenological investigation of cavernous sinus structure with special reference to paracavernous cranial nerves

Summary We have evaluated the anatomical structure of cavernous sinuses in parasellar blocks obtained from adult cadavers to gain clinically useful information. Ten microdissectional studies of parasellar blocks (20 sides of cavernous sinus) were carried out with special emphasis on the course of paracavernous cranial nerves (3rd to 6th). These were also examined on plain radiographs. Secondly, CT investigations of the cavernous sinuses (notably as to paracavernous cranial nerves) were undertaken in twenty clinical cases having presumed parasellar lesions and in three parasellar blocks from cadavers. The results from microdissectional studies and plain radiographs were as follows. It was found that the 3rd cranial nerve entered the lateral wall of the cavernous sinus close to the antero-inferior part of the posterior clinoid on lateral projection. The 4th cranial nerve, on the other hand, entered near the postero-inferior portion of the posterior clinoid on the same view. Variations in Parkinson's triangle were fairly often noted, although marked asymmetry was not seen in individual cases. From CT findings, it was found that a postenhanced, magnified direct coronal study was essential for identifying paracavernous cranial nerves more clearly. The 3rd and 5th cranial nerves were fairly well identified on axial and coronal projections. Careful radiological investigation including plain skull radiographs & CT seems to be of value for those who diagnose or treat parasellar lesions.     

Cavernous sinus invasion by pituitary adenomas

One hundred ninety-eight surgically explored pituitary adenomas were evaluated preoperatively by high-resolution computed tomography (CT). At surgery, evidence of direct cavernous sinus invasion was demonstrated in 19. CT findings in these cases included cavernous sinus expansion (17 patients) and visible encasement of the internal carotid artery (14 patients). The invasive tumor often enhanced to a lesser degree than the cavernous sinuses and ipsilateral internal carotid artery. Intracavernous cranial nerve compression, obliteration, or displacement (14 patients), invasion of the lateral wall of the cavernous sinus (seven patients), and diffuse bone destruction (seven cases) were other findings. Magnetic resonance imaging in three patients provided excellent demonstration of intracavernous internal carotid artery encasement, but displacement and obliteration of intracavernous cranial nerves was not shown as well as it was with CT. Histologically, only three patients showed anaplastic features and only one of them had distant metastases. There was no correlation between histologic features, hormone assays, and invasiveness. This experience indicates any type of pituitary adenoma, regardless of its endocrinologic activity, can invade the cavernous sinus. Cavernous sinus involvement makes complete surgical removal difficult. Preoperative recognition of invasive behavior of these tumors has prognostic value and aids in designing appropriate management. CT is the most useful technique generally available for evaluation and follow-up.     

The oculomotor cistern: anatomy and high-resolution imaging

BACKGROUND AND PURPOSE: The oculomotor cistern (OMC) is a small CSF-filled dural cuff that invaginates into the cavernous sinus, surrounding the third cranial nerve (CNIII). It is used by neurosurgeons to mobilize CNIII during cavernous sinus surgery. In this article, we present the OMC imaging spectrum as delineated on 1.5T and 3T MR images and demonstrate its involvement in cavernous sinus pathology.MATERIALS AND METHODS: We examined 78 high-resolution screening MR images of the internal auditory canals (IAC) obtained for sensorineural hearing loss. Cistern length and diameter were measured. Fifty randomly selected whole-brain MR images were evaluated to determine how often the OMC can be visualized on routine scans. Three volunteers underwent dedicated noncontrast high-resolution MR imaging for optimal OMC visualization.RESULTS: One or both OMCs were visualized on 75% of IAC screening studies. The right cistern length averaged 4.2 ± 3.2 mm; the opening diameter (the porus) averaged 2.2 ± 0.8 mm. The maximal length observed was 13.1 mm. The left cistern length averaged 3.0 ± 1.7 mm; the porus diameter averaged 2.1 ±1.0 mm, with a maximal length of 5.9 mm. The OMC was visualized on 64% of routine axial T2-weighted brain scans.CONCLUSION: The OMC is an important neuroradiologic and surgical landmark, which can be routinely identified on dedicated thin-section high-resolution MR images. It can also be identified on nearly two thirds of standard whole-brain MR images.

The oculomotor nerve (the third cranial nerve [CNIII]) is accompanied by a CSF-filled arachnoid-lined dural cuff as it enters the superolateral cavernous sinus roof. This oculomotor cistern (OMC) is well known to neurosurgeons as an avascular space used to expose and mobilize the nerve during cavernous sinus surgery. However, there has been no radiographic documentation and delineation of this cistern. The OMC is an important landmark for all surgeries involving the roof and lateral walls of the cavernous sinus, the basilar cisterns, the suprasellar area, and the middle cranial base.¹ It is important for radiologists and neurosurgeons planning tumor resection in this area to understand OMC MR imaging anatomy and pathology.We performed both a retrospective review of routine and high-resolution MR imaging of the brain as well as prospective dedicated imaging of the OMC and the surrounding structures to detail normal OMC imaging anatomy. We also illustrate its appearance in pathology involving the cavernous sinus.     

Perineural tumor extension to the cavernous sinus from superficial facial carcinoma: CT manifestations

The mechanism of cavernous sinus involvement by metastatic carcinoma from a facial primary tumor is poorly understood. The lack of lymphatic and obvious direct extension implicate either a vascular or perineural method of spread. The authors describe four patients who exhibited cavernous sinus metastases from facial carcinoma, all of whom experienced cranial nerve symptoms before the diagnosis of cavernous sinus involvement was made. Furthermore, the pathologic specimens from these patients exhibited extensive perineural involvement. The authors propose that the mechanism of metastasis in these patients is perineural extension.     

改良翼点入路显微直视手术切除海绵窦肿瘤

为总结海绵窦肿瘤显微神经外科治疗的经验，作者对1990年1月－2001年6月收治的26例海绵窦肿瘤病例进行了回顾性分析。手术均采用改良翼点入路，显微直视手术，其中6例在神经导航辅助下进行。结果全切19例（73.1%)部分切除7例（26.9%)。术后14例（53.8%)颅神经症状逐渐改善，6例（23.1%)出现新的颅神经损害症状，无死亡。对部分切除的病人，术后加立体定向放射外科治疗。随访8个月－12年，未见肿瘤复发。作者认为，熟悉海绵窦区的显微解剖并具备熟练的显微神经外科技术，可使该类手术取得良好效果。     

MR of oculomotor nerve palsy.

PURPOSETo assess the utility of MR in third cranial nerve palsy.METHODSWe reviewed precontrast and postcontrast MR of 50 patients with third cranial nerve palsy.RESULTSMR demonstrated an appropriate lesion in 32 cases. Of these patients, 6 had brain stem lesions and 15 had involvement of the nerve in the cavernous sinus; lesions of the cisternal segment of the nerve were present in 11 patients, with enhancement of this segment observed in 9 patients. An inflammatory or infiltrative source of the palsy was indicated in 19 of these 32 cases. Of 7 patients with pupillary involvement suggestive clinically of a compressive lesion, 4 demonstrated thickening and enhancement consistent with an infiltrative lesion of the nerve. Eighteen patients with pupil-sparing third cranial nerve palsies and a history of diabetes or vascular disease had normal MR findings, with no enhancement of the third cranial nerve observed.CONCLUSIONSPatients who do not have a history of diabetes or hypertension and in whom a complete or incomplete third cranial nerve palsy develops with or without pupil sparing should undergo MR imaging initially (unless there are clear symptoms or signs of subarachnoid hemorrhage) to exclude the presence of an infiltrative lesion or intraparenchymal process. Patients who have a history of vascular disease and a clinical presentation that is suggestive of an ischemic event may be observed initially, but should undergo imaging if improvement does not occur within 3 months.     

Perineural spread of malignant melanoma of the head and neck: clinical and imaging features

BACKGROUND AND PURPOSE: Extension of malignant melanoma along cranial nerves is a little-known complication of malignant melanoma of the head and neck. We describe the clinical and MR imaging findings of perineural spread of malignant melanoma to cranial nerves, emphasizing that this entity occurs more commonly with desmoplastic histology and may have a long latent period following primary diagnosis. METHODS: At two institutions, we identified and retrospectively reviewed eight cases of malignant melanoma of the head and neck that had MR imaging evidence of perineural spread of disease. All patients underwent confirmatory tissue sampling. RESULTS: Seven patients had melanomas of the facial skin or lip, and one patient had a primary sinonasal lesion. By histopathology, these melanomas included five desmoplastic, two mucosal, and one poorly differentiated melanotic spindle-cell tumor. All patients developed symptomatic cranial neuropathy an average of 4.9 years from the time of initial diagnosis. MR imaging demonstrated postgadolinium enhancement of at least one branch of the trigeminal nerve in all cases and of at least one other cranial nerve in five cases. Other findings included abnormal contrast enhancement and soft tissue thickening in the cavernous sinus, Meckel's cave, and/or the cisternal segment of the trigeminal nerve. CONCLUSION: Although perineural spread of disease occurs most commonly with squamous cell carcinoma and adenoid cystic carcinoma, malignant melanoma must also be included in this differential diagnosis, particularly if the patient's pathology is known to be desmoplastic. Similarly, any patient with malignant melanoma of the head and neck who undergoes MR imaging should receive an imaging assessment focused on the likely routes of perineural spread.     

Detailed imaging of abducens nerve anatomy using contrast-enhanced 3D-TOF MR angiography

PurposeCranial nerves (CNs), particularly CN IV and VI are difficult to visualize with conventional MRI techniques, particularly within the cavernous sinus region. The aim of this study was to evaluate the capacity of high-resolution contrast enhanced 3D time-of-flight (TOF) MR angiography using new generation 3 T imaging technology to provide detailed visualization of CN VI anatomy, particularly within the cavernous sinus and petroclival regions.MethodsTwo neuroradiologists conducted bilateral evaluation of CN VI visibility in 23 patients for nerve segments located in the petroclival segment (dural cave and Dorello's canal), and three divisions of the cavernous sinus. All images were collected using contrast enhanced TOF MR angiography using a new generation 3 T machine.ResultsOf the CN VI segments assessed, average visibility of CN VI was best achieved in Dorello's canal. Overall visibility of CN VI within the regions inspected was best achieved in the axial view, with the exception of the dural cave, which was best assessed using the coronal view.We also identified strong agreement in assessment of nerve visibility between the two reviewers.We also identified a putative CN6 duplication and a small schwannoma, highlighting the fidelity of our approach.ConclusionContrast enhanced 3D TOF MR angiography can visualize CN VI anatomy, particularly within the petrocavernosal region and cavernous sinus with simultaneous visualization of arterial and venous structures. This cannot be easily achieved using traditional MRI techniques. This imaging technique might be used with new generation machines to evaluate CN VI anatomy and pathologies within the petrocavernosal region and cavernous sinus, especially relating to vascular pathologies.     

3T MR三维稳态进动快速成像序列显示脑池段颅神经及其与周围病变的关系

目的探讨3T MR三维稳态进动快速成像(3D-FIESTA)序列显示中、后颅窝颅神经及其与周围病变关系的价值。方法对34例颅内脑外病变的患者行反转恢复SE T1WI、FSE T2WI及3D-FIESTA序列扫描。脑池段颅神经与周围病变的关系情况与手术结果相对照。结果 34例患者中共48处病变,3D-FIESTA序列显示9条神经被周围病变包绕,51条颅神经被压迫,与病变相邻的颅神经有10条,病变累及其邻近25条神经;其中23例患者行手术治疗,手术与MR图像对照,3D-FIESTA显示颅神经与周围病变关系的准确性分别为5/6、26/28、3/3、12/13。结论 3T MR 3D-FI-ESTA序列可以正确显示脑池段颅神经及其与周围病变的关系,对治疗前评估及病变的治疗有重要的应用价值。     

鼻咽癌侵犯前中颅窝的MRI表现

目的探讨鼻咽癌向前、中颅窝侵犯的ＭＲＩ征象。方法回顾分析３９例有颅神经损伤并经病理确诊的鼻咽癌病例,用１．０Ｔ磁共振机,行头颅、鼻咽部轴位和冠状面Ｔ１ＷＩ、Ｔ２ＷＩ和矢状面Ｔ２ＷＩ扫描,应用钆喷替酸葡甲胺（ＧｄＤＴＰＡ）增强后,分别行轴位、冠状面、矢状面Ｔ１ＷＩ扫描。结果（１）前颅窝受侵１３例,筛窦受侵３例,眶尖、球后受侵４例,两者同时受侵６例。（２）中颅窝受侵３８例,蝶骨体破坏３２例,蝶窦肿块２５例,破裂孔异常２０例,卵圆孔异常２８例,蝶鞍破坏６例,海绵窦受侵３５例。结论鼻咽癌经破坏颅底骨质、进出颅腔的自然骨性通道和两者并存的３种途径向前、中颅窝侵犯,ＭＲＩ能准确显示侵犯途径和程度     

Visualization of the lower cranial nerves by 3D-FIESTA

MR cisternography has been introduced for use in neuroradiology. This method is capable of visualizing tiny structures such as blood vessels and cranial nerves in the cerebrospinal fluid (CSF) space because of its superior contrast resolution. The cranial nerves and small vessels are shown as structures of low intensity surrounded by marked hyperintensity of the CSF. In the present study, we evaluated visualization of the lower cranial nerves (glossopharyngeal, vagus, and accessory) by the three-dimensional fast imaging employing steady-state acquisition (3D-FIESTA) sequence and multiplanar reformation (MPR) technique. The subjects were 8 men and 3 women, ranging in age from 21 to 76 years (average, 54 years). We examined the visualization of a total of 66 nerves in 11 subjects by 3D-FIESTA. The results were classified into four categories ranging from good visualization to non-visualization. In all cases, all glossopharyngeal and vagus nerves were identified to some extent, while accessory nerves were visualized either partially or entirely in only 16 cases. The total visualization rate was about 91%. In conclusion, 3D-FIESTA may be a useful method for visualization of the lower cranial nerves.     

Added value of contrast-enhanced CISS imaging in relation to conventional MR images for the evaluation of intracavernous cranial nerve lesions

Introduction  

The normal cranial nerves (CNs) of the cavernous sinus can be clearly demonstrated using contrast-enhanced constructive interference in steady-state (CISS) magnetic resonance imaging (MRI). This study used the method to evaluate pathological CNs III, IV, V₁, V₂, and VI in cavernous sinuses affected by inflammatory and neoplastic diseases.     

Dynamic MR imaging in Tolosa-Hunt syndrome

OBJECTIVE: To evaluate the cavernous sinuses with dynamic magnetic resonance (MR) imaging in patients with Tolosa-Hunt syndrome (THS). METHODS: The sellar and parasellar regions of five patients with THS and 12 control subjects were examined with dynamic MR (1.5 T) imaging in the coronal plane. Dynamic images were obtained with spin-echo (SE) sequences in three patients, and with fast spin-echo (FSE) sequences in two patients and control subjects. Conventional MR images of the cranium including sellar and parasellar regions were also obtained on T1-weighted pre- and post-contrast SE, and T2-weighted FSE sequences in the coronal plane. RESULTS: MR images revealed affected cavernous sinus with bulged convex lateral wall in three patients and concave lateral wall in two patients. In all control subjects, cavernous sinuses were observed with concave lateral wall. The signal intensity on T1- and T2-weighted images and contrast enhancement on post-contrast images of the affected cavernous sinuses in patients were similar to those of the unaffected cavernous sinuses in patients and control subjects. The dynamic images in all patients disclosed small areas adjacent to the cranial nerve filling-defects within the enhanced venous spaces of the affected cavernous sinus, which showed slow and gradual enhancement from the early to the late dynamic images. No such gradually enhancing area was observed in control subjects except one. The follow-up dynamic MR images after corticosteroid therapy revealed complete resolution of the gradually enhancing areas in the previously affected cavernous sinus. CONCLUSION: Dynamic MR imaging may facilitate the diagnosis of THS.     

Imaging of perineural tumor spread from palatal carcinoma.

Carcinomas of the hard or soft palate are known to spread perineurally along palatine branches of the maxillary nerve. Imaging of perineural tumor spread from the palate has been underemphasized in the imaging literature. We report the findings from eight patients in whom spread from primary cancers of the palate was seen along the palatine nerves. Indications of perineural spread include enlargement or excessive enhancement of a nerve, or abnormal density/signal intensity, enhancement, or widening of the pterygopalatine fossa, cavernous sinus, or Meckel''s cave.     

Diagnostic imaging and differential diagnosis of pathological processes of the sinus cavernosus

To describe the different imaging modalities for the evaluation of pathological changes in the cavernous sinus as well as to compile criteria for differential diagnosis. Imaging of the cavernous sinus comprises the primary use of tomographic modalities such as CT or MRI.The continuing development of multislice-CT (MSCT) allows the depiction of bony structures of the cavernous sinus with a high resolution.Secondary reconstructions of the acquired data set allow a reliable evaluation especially of the bony topography including the foraminae of nerves and vessels. Uni- or bilateral structures can be visualized using contrast-enhanced CT.CT-angiography is capable of demonstrating the course of the internal carotid artery and its involvement in pathologies of the cavernous sinus, this recent achievement has only been made available by use of the current short scanning times. Contrast-enhanced MRI in axial and coronal orientation, optionally using fat saturation techniques as well as arterial and venous MRI-angiography (MRA) are used to depict the soft parts of the cavernous sinus. Care must be taken to cover all topographic detail including different signal intensities, as multiple inborn, neoplastic, infectious or traumatic changes can be present hampering the radiologic diagnosis of the cavernous sinus. Uni- and bilateral infiltration of the cavernous sinus as well as vascular involvement represent additional criteria leading to the differential diagnosis.The advent of dynamic sequences as well as diffusion and perfusion weighted MRI have broadened the spectrum of diagnostic modalities. Digital subtraction angiography as an invasive technique is used during therapeutic procedures such as the local treatment of aneurysms or carotid-cavernous fistulas.