Idiopathic hypertrophic cranial pachymeningitis: case report with 7 years of imaging follow-up

Idiopathic hypertrophic cranial pachymeningitis is a rare inflammatory disease with diffused involvement of the dura. Often, the definite diagnosis is made immediately with biopsy and the involved dura is removed surgically. Consequently, extensive preoperative imaging studies usually are not available. We reviewed a case of idiopathic hypertrophic cranial pachymeningitis and collectively summarized the interesting features from the 7 years preceding surgical treatment. These chronologic imaging findings with progressive intracranial involvement included dural thickening, dural mass, sinus thrombosis, and venous congestion constituted comprehensive pictures of idiopathic hypertrophic cranial pachymeningitis. The thickened dura may also at times mimic dural masses, such as en plaque meningioma.     

Hypertrophic cranial pachymeningitis involving dural sinuses: a pseudo signal-void appearance on MRI

A case of hypertrophic cranial pachymeningitis with an unusual and misleading manifestation is reported. CT detected calcified tentorium and superior sagittal sinus. MR imaging and MR angiography depicted tentorial thickening as well as occlusion of all major dural sinuses. Fibrocalcific occlusion of dural sinuses showed interestingly signal-void appearance on spin-echo images which could readily be interpreted as being patent sinuses.     

Idiopathic hypertrophic pachymeningitis: spectrum of the disease

Hypertrophic pachymeningitis is extremely rare. It is a fibrosing inflammatory process which involves the dura mater, including the tentorium. Numerous pathological entities produce thickening of the pachymeninges, so that idopathic hypertrophic pachymeningitis is a diagnosis of exclusion. We describe four patients with idiopathic hypertrophic pachymeningitis who had varied clinical presentation. Imaging studies revealed diffuse thickening of the pachymeninges; in one patient there was extensive dural sinus thrombosis. Since no identifiable cause was found, the cases were labelled as idiopathic. Received: 4 July 1996 Accepted: 1 November 1996     

Cranial epidural tuberculoma. A case report

A 33-year-old patient with cranial epidural tuberculoma without history of tuberculosis is described. CT and MR imaging showed a lesion located on both sides of a right frontotemporal bone destruction with epidural extent. Except for a small necrotic core, the lesion enhanced intensely after contrast medium administration. Osteitis and subgaleal abscess were associated. The displaced dura mater delineated the epidural tuberculoma. Diagnosis was verified by histology and identification of Mycobacterium tuberculosis. After removal of the tuberculoma and combination therapy, there was a complete regression of abnormalities. Differential diagnoses are dural tuberculoma, focal tuberculous pachymeningitis and tuberculous epidural empyema.     

颅内硬膜外积脓的影像诊断

目的　评估MR和CT对颅内硬膜外积脓的诊断价值。方法　对 4例颅内硬膜外积脓的CT和MR表现进行分析。结果　 2例额部 ;1例额顶部 ;1例后颅窝。 4例颅内硬膜外积脓处硬膜明显增厚 ,均匀强化 ,局部骨板侵蚀破坏变薄或增生。结论　CT和MR可以清楚显示颅内硬膜外积脓的形态学和病理学改变 ,因此CT和MR是诊断颅内硬膜外积脓最有价值的方法     

Dural "tail" associated with meningiomas on Gd-DTPA-enhanced MR images: characteristics, differential diagnostic value, and possible implications for treatment

Gadolinium-enhanced magnetic resonance (MR) imaging studies of 30 histologically proved cranial meningiomas revealed a linear enhanced structure or "tail" extending away from the tumor mass along the dural surface in 18 cases (60%). Contrast material-enhanced computed tomographic studies available in 10 of these 18 cases did not depict this structure. Characteristic features of this MR finding were reviewed, and criteria were defined to distinguish this tail from other enhanced structures. To assess the differential diagnostic value of this finding, gadolinium diethylenetriaminepentaacetic acid-enhanced MR studies of a control group of other extraaxial lesions as well as superficial intraaxial tumors that abut the meninges were reviewed. These cases failed to show this MR feature. Pathologic correlation was available in three meningiomas with the finding of a tail, and these demonstrated meningothelial tumor nodules in the samples taken from areas corresponding to the enhanced regions on MR images. This is in agreement with other recent pathologic studies of the dura mater surrounding meningiomas. The authors believe that the linear enhanced structure described may represent tissue containing tumoral nodules. Awareness of this MR sign may be useful in distinguishing meningiomas from other lesions and in planning total resection of the infiltrated dura mater.     

Thickening of dura surrounding meningiomas: MR features

Thickening of the dura in continuity with a convexity meningioma was noted on T1-weighted magnetic resonance (MR) images in seven patients. In five cases the corresponding CT image of the lesions was typical of meningioma. In two other cases the CT image of the lesions was atypical, owing to cyst formation in one and extensive edema in the other. After intravenous injection of paramagnetic contrast medium in four patients, the thickened dura demonstrated contrast enhancement at a variable distance from the tumor. In three patients the thickened dura was confirmed surgically. Pathology, available in one case, showed the thickened dura to correspond to tumoral extension within or around the dura. Magnetic resonance demonstration of thickening of the dura in continuity with a mass at the cerebral convexity may prove to be of importance in the differentiation of atypical lesions on CT and MR, especially with lower field magnets. Moreover, it could provide useful information to the neurosurgeon for more complete resection of the tumor.     

Idiopathic hypertrophic cranial pachymeningitis: a case report

Hypertrophic pachymeningitis is a rare fibrosing inflamatory process involving dura mater and tentorium. In this report we are presenting contrast enhanced MRI findings of an unusual case of pachymeningitis which presented with a periorbital mass due to dural sinuses occlusion and retrograde filling of periorbital veins through superior sagittal sinus.     

Cranial postoperative site: assessment with contrast-enhanced MR imaging

To define duration and patterns of postoperative contrast material enhancement, the authors evaluated magnetic resonance (MR) images obtained with gadolinium diethylenetriaminepentaacetic acid (DTPA) in 46 patients who had undergone major intracranial surgery. Intervals between surgery and MR imaging ranged from 1 day to 40 years (median, 1.3 years). Moderate or marked brain and dural enhancement was noted in nearly every patient imaged within 3 months of surgery, but all brain enhancement was gone by 1 year. Abnormal dural enhancement was noted in every patient imaged within 1 year of surgery and in approximately 50% at 1-2 years afterward. One patient had persistent mild enhancement of the dura 40 years after surgery. MR images revealed enhancement in several sites not frequently recognized on computed tomographic (CT) scans. Brain and meningeal enhancement with Gd-DTPA at cranial operative sites was more extensive and persisted much longer than is commonly seen on contrast-enhanced CT scans. Enhancement of the brain or pia mater does not normally last beyond 1 year, but dural enhancement may persist for decades.     

MR imaging findings of spinal dural involvement with Wegener granulomatosis

Involvement of the brain and meninges is rare in cases of Wegener granulomatosis, occurring in 2% to 8% of cases. Meningeal involvement in association with Wegener granulomatosis has scarcely been reported as being confined to the dura mater of brain on images and is thought to represent granulomatous infiltration. There are a few reported cases of Wegener granulomatosis that document involvement of dura at the level of the spinal cord. We present the case of a 52-year-old man with Wegener granulomatosis involving the cervical spinal dura and include detailed MR imaging findings.     

Dural metastases from prostate carcinoma: A systematic review of the literature apropos of six patients

Intracranial metastases are a rare manifestation of prostate carcinoma and the dura mater is the most affected site. We report a series of six patients with dural prostate metastases (DPM) and perform a systematic review of the current literature in order to depict imaging trademarks of this condition. This review points to a magnetic resonance imaging (MRI) pattern of meningeal involvement characterized by a diffuse smooth thickening, nodular appearance or dural-based masses. We also demonstrate an osteoblastic pattern of lesions, particularly in sphenoid wing, by computed tomography (CT) scans. We suggest that these imaging findings may support an elevated index of suspicion of DPM in elderly men, including those patients without urologic symptoms.     

Intracranial adenoid cystic carcinoma mimicking meningioma: report of two cases

Two cases of intracranial adenoid cystic carcinoma mimicking meningioma are reported. In one, MRI showed not only a homogeneously enhancing extra-axial tumour attached to the dura mater of the posterior cranial fossa, but also surrounding dural enhancement, the dural tail sign. In the second, CT demonstrated a well-demarcated enhancing extra-axial tumour, indistinguishable from a sphenoid ridge meningioma extending into the orbit. The neuroradiological features of intracranial adenoid cystic carcinoma may thus closely resemble those of meningioma.     

Prominent meningeal enhancement adjacent to meningioma on Gd-DTPA-enhanced MR images: histopathologic correlation

To assess tissue changes responsible for enhancement of the meninges adjacent to meningiomas on magnetic resonance (MR) images, the authors correlated the MR imaging characteristics of meningeal lesions seen before and after administration of gadolinium diethylenetriamine-pentaacetic acid (DTPA) with the appearance of these lesions on contrast material-enhanced computed tomographic (CT) images and with histopathologic findings in four patients. Histopathologic examination of meninges showed increased loose connective tissue, hypervascularity, and dilated vessels. There was neoplastic infiltration of the dura mater in two patients but it was restricted to the immediate junction of neoplasm and dura mater, with maximum peripheral extension within 1 mm of the tumor margin. In both patients the meninges were enhanced far beyond the neoplastic infiltration. The other two patients showed no infiltration of dura mater. These findings suggest that pathologic enhancement of meninges adjacent to meningioma after administration of Gd-DTPA mainly represents reactive changes to the neoplasm and does not necessarily indicate neoplastic involvement.     

Dural congestion accompanying meningioma invasion into vessels: the dural tail sign

Our purpose was to verify the histological appearance of the dural tail accompanying meningiomas on MRI. We studied seven patients such a dural tale. We examined the point of attachment of the tumour and the adjacent dura mater histologically. In all patients, rich vascularity and dilated vessels were observed in the dura mater at the point of attachment of the tumour; tumour cells invaded the dura mater and vessels, packing the latter. In the adjacent dura mater, showing as a dural tail on MRI, there was tumour-cell invasion in only one patient. Vascular congestion around the vessels compacted by the tumour cells in the dura mater and dilated vessels were seen in all patients. We therefore suggest that the mechanism of the dural tail sign is as follows. First, tumour cells invade vessels and pack them at the point of tumour attachment. Then, vessel congestion is induced in the adjacent dura mater, as a result of which it enhances markedly, giving rise to the dural tail sign. Received: 31 July 2000 Accepted: 29 September 2000     

Wegener granulomatosis: CT and MR findings.

PURPOSETo demonstrate the spectrum of CT and MR imaging findings in patients with Wegener granulomatosis and to determine how often these findings could be attributed to either direct extension from paranasal or orbital disease sites, remote granulomas, or central nervous system (CNS) vasculitis.METHODSWe retrospectively reviewed the CT or MR studies of 15 patients with Wegener granulomatosis.RESULTSAbnormal findings were seen in 7 patients (5 examined with MR imaging, 2 with CT). Findings included dural thickening and contrast enhancement (3 patients), infarcts (2 patients), regions of hyperintense signal on T2-weighted MR images (2 patients), and abnormal MR signal in the brain stem (2 patients). Three patients with imaging findings of dural enhancement and thickening were thought to have remote granulomatous lesions involving the dura. No patients had extension from sites external to the CNS or clinical findings suggestive of CNS vasculitis.CONCLUSIONThe spectrum of CT and MR findings in Wegener granulomatosis includes dural thickening and enhancements cerebral infarction, and MR signal abnormalities in the brain stem and white matter. Presumed remote granulomatous lesions were the most common causes of CNS findings in this study. Complications related to non-CNS disease (eg, hypertension, endocarditis) also appear to have played a role in some patients.     

Polygonal deformation of the dural sac in lumbar epidural lipomatosis: anatomic explanation by the presence of meningovertebral ligaments

BACKGROUND AND PURPOSE: In patients with epidural lipomatosis, axial lumbar spine CT and MR images occasionally reveal a geometric, polygonal or stellar, shape of the dural sac. The purpose of this study was to define the anatomic structures responsible for this radiologic appearance. We hypothesized that meningovertebral ligaments could anchor the dura mater to the osteofibrous walls of the spinal canal and account for the geometric deformation of the dural sac. METHODS: The epidural spaces were examined in 15 adult cadaveric and seven aborted fetal lumbar spines. For macroscopic studies, 70 adult vertebral segments were separated and dissected by removing the extradural fat. For microscopic examination, axial histologic sections were obtained from 35 fetal and five adult undissected vertebral segments. RESULTS: Meningovertebral ligaments were observed in the median, paramedian, and lateral aspects of the anterior and posterior epidural spaces of both adult and fetal lumbar spines. These ligaments anchor the outer surface of the dura mater to the osteofibrous walls of the lumbar canal. They may form an irregular longitudinal septum partitioning the epidural space. Histologic examination demonstrated the fibroelastic composition of these ligaments and suggested their possible perivascular morphogenetic origin. CONCLUSION: The morphologic and topographic features of the meningovertebral ligaments explain the polygonal, stellar, or Y-shaped deformation of the dural sac observed on axial CT and MR images in patients with lumbar epidural lipomatosis.     

The empty delta sign: frequency and significance in 76 cases of dural sinus thrombosis

The presence of the empty delta sign on contrast material-enhanced computed tomographic (CT) scans of the brain is considered pathognomonic of sagittal sinus thrombosis (SST); however, a valid explanation for its appearance is lacking, despite several hypotheses. To determine the frequency of the sign and its prognostic significance, 76 reported cases (112 CT manifestations) of SST and SST-related intracranial sinovenous occlusive disease were reviewed. Ten CT signs related to both disease processes were reported; the empty delta sign was the most frequently reported sign (28.6%) of SST. Patients with hemorrhagic infarction and/or the empty delta sign on CT scans had the poorest prognosis. A case illustrative of the empty delta sign is described in which there was engorgement of endothelial- and nonendothelial-lined spaces in the dura mater with hemorrhagic rupture into the dural leaf. The empty delta sign can probably be explained on the basis of the rich dural venous collateral circulation, consisting primarily of lateral lacunae, a vascular mesh (dural cavernous spaces), and meningeal venous tributaries.     

The dural tail sign--beyond meningioma

There have been somewhat conflicting reports published about the significance of linear meningeal thickening and enhancement adjacent to peripherally located cranial mass lesions on contrast-enhanced magnetic resonance (MR) images. Most of the authors consider this so-called "dural tail sign" or "flare sign" almost specific for meningioma. This review illustrates the MR imaging findings of a wide spectrum of disorders that show this dural sign. Causes include other extra-axial lesions and also peripherally located intra-axial lesions such as neuromas, chloromas, metastases, lymphoma, gliomas, pituitary diseases, granulomatous disorders, and also cerebral Erdheim-Chester disease. The dural tail sign is not specific to a particular pathological process. Nevertheless, useful conclusions can be drawn from the morphology of the lesion, its enhancement pattern, and its solitary or multifocal presentation. The final diagnosis must be based on cerebrospinal fluid studies or histological studies after biopsy.     

硬脑膜肥厚的MRI诊断及鉴别诊断分析

目的分析硬脑膜肥厚的MRI表现,探讨不同病理情况的影像学特点,以提高定性诊断水平。方法回顾分析36例经手术病理或临床证实的硬脑膜肥厚性疾病例纳入研究,其中男20例,女16例,年龄6～68岁,平均年龄(34±3.5)岁,采用西门子1.5T超导MR成像仪,完成横断面T2WI、T1WI、FLAIR和矢状面T2WI平扫,横断面、冠状面和矢状面T1WI增强及横断面FLAIR增强,2名高级职称影像医师共同回顾性分析MRI表现。结果低颅压综合征10例(27.8%),肥厚性硬脑膜炎10例(27.8%),其中1例为特发性,9例为感染性,硬脑膜转移瘤8例(22.2%),其中合并脑实质内小结节病灶5例,单纯局限性脑膜增厚3例,白血病颅内浸润1例(2.8%),系统性黄斑狼疮1例(2.8%),脑外伤后血肿形成2例(5.6%),脑肿瘤放疗后2例(5.6%),侵袭性脑膜瘤2例(5.6%),上述病例于MRI检查上均表现为硬脑膜弥漫性或局限性增厚。结论硬脑膜增厚疾病种类繁多,但根据病灶所发生的范围和是否伴随软脑膜及脑实质内强化结节等特征,并结合临床表现,多数能做出明确诊断。     

系统性恶性肿瘤所致脑膜癌病的磁共振成像表现

目的 探讨脑膜癌病的MRI表现特点,提高对脑膜癌病的影像学认识和诊断水平。方法 经确诊的脑膜癌病11例,MR常规扫描后均行钆喷替酸葡甲胺（Gd－DTPA）增强扫描,对其增强特点及病变类型进行回顾性分析。结果 MR平扫均未见脑膜异常信号。增强扫描后9例显示软脑膜异常增强,表现为脑表面连续的、可延伸至脑沟内的细线状高信号,累及范围包括小脑、脑干及大脑表面,但未见明确的蛛网膜下腔异常增强。3例显示硬脑膜－蛛网膜异常增强,表现为大脑凸面,其中1例同时累及小脑凸 面和小脑幕。9例累及软脑膜者脑脊液均为异常,2例仅累及硬脑膜－蛛网膜者脑脊液均为正常。结论 MR增强扫描能很好地显示脑膜癌病,根据增强特点可以区分脑膜癌 病的类型,结合临床对脑膜癌病能作出诊断并指导治疗。