Contrast-enhanced MR images in patients with meningioma: importance of enhancement of the dura adjacent to the tumor

Linear enhancement (flare sign) along the dura mater that was continuous with or emanated from the dural margin of meningiomas was frequently observed on contrast-enhanced MR images obtained in 18 patients with intracranial meningiomas (surgically proved). Preoperative MR studies obtained at 1.5 T after administration of gadopentetate dimeglumine were reviewed retrospectively to determine the clinical significance of this sign. Thirteen (72%) of the 18 meningiomas exhibited the finding adjacent to the dural attachments. Four meningiomas of the cerebellopontine angle showed enhancement along the internal auditory canals. Three specimens of the dura adjacent to the tumor in different patients with this finding revealed proliferation of connective tissues abounding with vessels along the dura without definite tumor invasion. The flare sign is thought to be a common finding of meningiomas on contrast-enhanced MR images obtained with high-resolution sequences, and it is observable without tumor invasion. This sign in the cerebellopontine angle should not be misinterpreted as enhancement of acoustic schwannomas.     

Dural invasion of meningiomas adjacent to the tumor margin on Gd-DTPA-enhanced MR images: histopathologic correlation

In intracranial meningiomas a flat, contrast-enhancing, dural structure adjacent to the tumor can occasionally be observed on gadolinium-DTPA-enhanced MR images. We wished to evaluate whether there is a correlation between MR images and meningeal invasion of intracranial meningiomas. The study included 54 patients with intracranial meningioma and the meningeal sign. MR studies included T2-weighted and gadolinium-DTPA-enhanced T1-weighted images in axial, coronal, and sagittal planes. Histopathologic examinations were done on the meningiomas adjacent to the dura mater. The meningeal sign on MRI was observed from 2 up to 35 mm from the main tumor mass in 31 (57 %) of the 54 patients. In 20 of these 31 the histopathologic examination showed tumor invasion, while 11 patients had no tumor invasion but tissue proliferation, hypervascularity, and vascular dilatation. Seven of the 23 meningiomas without the meningeal sign had histologically proven infiltration of the adjacent dura. MR imaging is not able to determine definitive whether or not there is dural infiltration of the meningiomas. In conclusion, resection of the tumor with a wide margin is necessary to achieve complete excision of meningioma and to avoid recurrence. Received 23 July 1997; Revision received 10 October 1997; Accepted 17 October 1997     

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.     

MR imaging of myositis ossificans: Variable patterns at different stages

Five patients with a palpable mass at presentation underwent magnetic resonance (MR) imaging. The final diagnosis was myositis ossificans (MO). MR imaging features, particularly after injection of gadopentetate dimeglumine, mimicked those of an inflammatory mass or neoplasm. The lesions were excised in three patients, and the Images were correlated with histologic findings. Three different appearances were noted on MR images, corresponding to the stages of maturation of MO. Two cases Involved early-stage lesions, and Tl-weighted MR images showed a mass with homogeneous intermediate signal intensity. Both lesions showed rim enhancement after contrast agent injection and high signal intensity on T2-weighted images. Pathologic specimens demonstrated stroma with masses of spindle cells in which osteoid production was interspersed. The enhanced rim of the lesion mimicked the expected MR appearance of an abscess or necrotic tumor. Areas of enhancement in adjacent muscle were also seen on postcontrast T1-weighted images. Intermediate-stage MO was present in one case; there was evidence of a thin rim of calcification on plain radiographs and fatty changes in the lesion on T1-weighted Images, corresponding with histologic findings. One case of a mature lesion showed a considerable degree of peripheral calcification both on MR images and at histology. MR imaging is nonspecific in the diagnosis of early-stage MO.     

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.     

Intracranial solitary fibrous tumors: imaging findings in 6 consecutive patients

BACKGROUND AND PURPOSE: Intracranial solitary fibrous tumors (ISFTs) are rare mesenchymal neoplasms originating in the meninges. The aim of this study was to describe the CT, MR imaging, and angiographic features of the solitary fibrous tumor and to identify imaging characteristics. MATERIALS AND METHODS: We retrospectively reviewed CT, MR, and angiographic findings in 6 cases of ISFT. We evaluated the size, shape, and location of the tumor; the internal content and margin of the lesion; the pattern of enhancement; and the change of the adjacent structures. Density on noncontrast CT scans, signal intensity on MR images, and angiographic features were also documented. RESULTS: Each lesion appeared as a discrete extra-axial mass (size, 3-7 cm; mean, 5 cm). Five lesions were entirely solid, and 1 had peritumoral cyst. All 5 of the noncontrast CT scans showed hyperattenuated masses, and the tumors exhibited marked heterogeneous enhancement. No lesion contained calcification, and 2 cases showed bone invasions. On the MR images, 4 lesions showed mixed signal intensity on T2-weighted imaging. All of the lesions revealed marked heterogeneous enhancement. All of the tumors had thickening of the meninges adjacent to the tumor. Angiography showed delayed tumor blushing in all, and 3 of them had dysplastic dilation of the tumor vessels. CONCLUSION: Although there are no pathognomonic imaging findings, some imaging features, such as the "black-and-white mixed" pattern on T2-weighted images and marked heterogeneous enhancement, might be helpful in the diagnosis of intracranial solitary fibrous tumor.     

淋巴细胞性垂体炎的MRI表现

目的 描述淋巴细胞性垂体炎的MRI表现，探讨MRI的诊断价值和限度及其与垂体腺瘤的鉴别诊断。方法 对5例临床以多饮、多尿及头痛为主要症状前来就诊，手术病理诊断为淋巴细胞性垂体炎患者的术前MR影像及其临床资料进行回顾性分析。结果 5例淋巴细胞性垂体炎患者MRI均表现为垂体增大，垂体蒂增粗，正常神经垂体T1WI高信号消失，病变均呈明显强化，其中2例为均匀强化，3例强化不均匀。2例可见海绵窦及相邻硬脑膜受侵犯。结论 对于垂体增大合并中枢性尿崩症，伴或不伴有腺垂体功能低下的患者要考虑淋巴细胞性垂体炎的诊断。     

Iron-oxide-enhanced MR imaging of bone marrow in patients with non-Hodgkin's lymphoma: differentiation between tumor infiltration and hypercellular bone marrow

The aim of this study was to differentiate normal, hypercellular, and neoplastic bone marrow based on its MR enhancement after intravenous administration of superparamagnetic iron oxides in patients with cancer of the hematopoietic system. Eighteen patients with cancer of the hematopoietic system underwent MRI of the spine before and after infusion of ferumoxides ( n=9) and ferumoxtran ( n=9) using T1- and T2-weighted turbo spin-echo (TSE) and short tau inversion recovery sequences (STIR). In all patients diffuse or multifocal bone marrow infiltration was suspected, based on iliac crest biopsy and imaging such as conventional radiographs, MRI, and positron emission tomography. In addition, all patients had a therapy-induced normocellular ( n=7) or hypercellular ( n=11) reconversion of the normal non-neoplastic bone marrow. The MRI data were analyzed by measuring pre- and post-contrast signal intensities (SI) of hematopoietic and neoplastic marrow and by calculating the enhancement as deltaSI(%) data and the tumor-to-bone-marrow contrast as contrast-to-noise ratios (CNR). Changes in bone marrow signal intensity after iron oxide administration were more pronounced on STIR images as compared with T1- and T2-weighted TSE images. The STIR images showed a strong signal decline of normal and hypercellular marrow 45-60 min after iron oxide infusion, but no or only a minor signal decline of neoplastic bone marrow lesions; thus, deltaSI% data were significantly higher in normal and hypercellular reconverted marrow compared with neoplastic bone marrow lesions ( p<0.05). Additionally, the contrast between focal or multifocal neoplastic bone marrow infiltration and normal bone marrow, quantified by CNR data, increased significantly on post-contrast STIR images compared with precontrast images ( p<0.05). Superparamagnetic iron oxides are taken up by normal and hypercellular reconverted bone marrow, but not by neoplastic bone marrow lesions, thereby providing significantly different enhancement patterns on T2-weighted MR images; thus, superparamagnetic iron oxides are useful to differentiate normal and neoplastic bone marrow and to increase the bone marrow-to-tumor contrast.     

Prominent dural enhancement adjacent to nonmeningiomatous malignant lesions on contrast-enhanced MR images

Prominent dural enhancement was noted in 10 (16%) of 61 superficial malignant intracranial tumors studied with contrast-enhanced MR imaging during a 2-year period. Included were six glioblastomas, three parenchymal metastases, and one case of dural metastasis. Seven patients had surgery. In four, there was extensive leptomeningeal invasion in the center of the lesion. In two of these lesions there was firm attachment of the center of the tumor to the dura, but without dural invasion despite extensive external carotid artery supply to the tumor in one case. In two cases the overlying dura was normal, and there was no leptomeningeal tumoral invasion. In the case of dural metastasis, huge nodular lesions were present along the inner aspect of the dura. In none of the cases did prominent dural enhancement adjacent to the tumor correspond with tumoral invasion or extension to the dura. Prominent dural enhancement on contrast-enhanced MR images appears to be much less frequent in malignant tumor than in meningioma, where it is seen in up to 60% of the cases. We believe this finding is more likely to represent reactive changes of the dura than tumoral invasion.     

Postoperative evaluation for intracranial recurrence of medulloblastoma: MR findings with gadopentetate dimeglumine.

PURPOSETo characterize the gadopentetate dimeglumine-enhanced MR features of recurrent medulloblastoma.METHODSThe postsurgical gadopentetate dimeglumine-enhanced MR images of 48 patients (206 head examinations) with prior resection of medulloblastoma were retrospectively evaluated for enhancement in the brain parenchyma, meninges (dura, pia-arachnoid), and ventricles.RESULTSNineteen patients had recurrent tumor as determined by clinical course and positive imaging studies. Seventeen patients with recurrent disease had intracranial enhancement predominating in the pia-arachnoid (63%) or as a focal nodular brain lesion (26%). Three of these patients also had intraventricular metastases. None of the clinically healthy patients had these findings. One patient had recurrent tumor presenting within the fourth ventricle. Only 3 of 8 intraventricular lesions observed in the 4 patients initially enhanced with gadopentetate dimeglumine. Another patient with recurrent disease had extensive skeletal metastases without involvement of the central nervous system. Dural enhancement was observed in patients both with (42%) and without (38%) recurrent tumor.CONCLUSIONThe MR findings of pia-arachnoidal or focal nodular brain enhancement are highly specific in the diagnosis of recurrent medulloblastoma. Pia-arachnoidal or focal brain enhancement were also the most frequent patterns associated with recurrent tumor. Dural enhancement alone is not a reliable indicator of recurrent medulloblastoma. Not all intraventricular metastases enhance with gadopentetate dimeglumine, and careful evaluation for nonenhancing lesions within the ventricles should be made on postoperative MR examinations.     

脊柱区淋巴瘤的MRI特征

目的 分析脊柱区淋巴瘤的MRI表现,以提高对其的认识.方法 回顾性分析经手术及穿刺病理或临床随访证实的脊柱区淋巴瘤45例,其中原发性5例,均为非霍奇金淋巴瘤(NHL);继发性4|D例,其中霍奇金淋巴瘤(HL)9例,NHL 31例(B细胞型27例,T细胞型4例).将MRI表现与临床、病理结果进行对照.结果 (1)病变部位:单部位发病者13例,多部位发病者32例.5例原发性者均为单部位发病,继发性者40例中32例为多发.(2)病变类型:骨质破坏型27例,表现为不同程度的骨质破坏,23例合并有软组织肿块,18例软组织病变的范围超过骨质破坏的范围;软组织肿块型6例,骨质破坏不明显,5例表现为椎管内外软组织肿块并经椎间孔相连,呈围椎、钻孔生长的特点;骨髓浸润型9例,表现为椎骨髓质MRI信号异常,骨皮质完整,椎旁软组织正常;脊髓浸润型3例,表现为脊髓增粗和MRI信号异常.(3)MRI表现:椎骨骨质破坏和骨髓浸润表现为T1WI低信号,T2WI低、等或高信号,压脂T2WI高信号.软组织肿块与相邻正常肌肉相比,T1WI呈均匀低信号,T2WI呈高信号.增强扫描肿块多呈轻至中度强化,坏死液化不明显.结论 脊柱区淋巴瘤多为继发性B细胞NHL,其主要表现是溶骨性骨质破坏伴较大范围的软组织肿块,肿块有经椎间孔相连围椎、钻孔生长的特点,增强扫描呈轻至中度均匀强化.     

MR findings in eosinophilic infiltration of the liver

OBJECTIVE: This study describes the findings of magnetic resonance imaging (MRI) of focal eosinophilic infiltration of the liver. METHODS: Contrast-enhanced MR images of 8 patients with focal hepatic eosinophilic infiltration were reviewed retrospectively. We evaluated the signal intensity of focal lesions in T1-weighted and T2-weighted images and the pattern of enhancement in a dynamic contrast study. RESULTS: A total 22 focal hepatic lesions were observed; the lesions were isointense (55%) or hypointense (45%) on T1-weighted images and isointense (14%) or hyperintense (86%) on T2-weighted images. The arterial phase of the contrast study revealed 11 hyperintense lesions (50%). During the portal and delayed phases, 18 (82%) and 17 lesions (77%) were hyperintense, respectively. CONCLUSION: The focal eosinophilic infiltrations showed homogeneous enhancement in the portal and delayed phases in the dynamic contrast MR study. These findings should help to distinguish focal eosinophilic infiltration, especially from metastasis in patients with malignancy.     

Fibrosing inflammatory pseudotumors involving the skull base: MR and CT manifestations with histopathologic comparison.

PURPOSETo describe the MR and CT features of fibrosing inflammatory pseudotumors of the skull base region, and to document the MR signal intensity of the lesions with histopathologic comparison.METHODSWe reviewed the MR and CT studies of five patients with pathologically proved fibrosing inflammatory pseudotumor involving the skull base. Unenhanced spin-echo T1- and T2-weighted and contrast-enhanced T1-weighted MR images were obtained at 0.5 T in three patients and at 1.5 T in two patients. MR findings were correlated with histopathologic findings in all five cases, and the enhancement pattern was compared with CT findings in three cases.RESULTSIn three cases, the cavernous sinus was involved unilaterally, with adjacent extracranial infiltrative masses. In one case, both orbits, the cavernous sinuses, and the tentorium were involved with diffuse infiltrative lesions. One patient had an infiltrative nasopharyngeal mass; and in all five patients, MR images showed localized involvement of the skull base, with bone marrow replaced by tumor. The soft-tissue lesions were hypointense on T2-weighted images in all five cases and showed homogeneous contrast enhancement. Histopathologic studies revealed scanty inflammatory cell infiltration with densely fibrotic background in all cases. The hypointensity of the lesions on T2-weighted images seemed to be related to the degree of fibrosis.CONCLUSIONFibrosing inflammatory pseudotumor shows characteristic MR findings of infiltrative lesion with bone destruction and hypointensity on T2-weighted images. The lack of mobile protons due to the fibrotic background and/or high cellularity of the lesions may be the reason for their hypointensity and weaker enhancement on MR images.     

Epithelioid hemangioendothelioma of the liver: imaging findings with pathologic correlation.

Hepatic epithelioid hemangioendothelioma is a rare malignant neoplasm that has nonspecific clinical signs and symptoms and can be difficult to diagnose on the basis of biopsy results. Radiologists may suggest the diagnosis of this slowly progressive neoplasm by recognizing its characteristic radiologic features. We correlated images from CT (13), sonography (nine), and MR (six) with pathologic findings in resected whole livers (eight) and biopsy specimens (five) from 13 patients 25-58 years old. Gross pathologic examination showed a repetitive pattern of multiple solid tumor nodules, in a predominantly peripheral distribution, with coalescence as individual nodules exceeded 4 cm. Tumor nodules had a hyperemic rim. Lesions adjacent to the capsule often produced capsular retraction. These findings correlated well with imaging findings. On CT, the lesions were of low attenuation, peripherally based, and with capsular retraction or flattening in nine (69%) of 13 patients. Unenhanced CT scans showed superior conspicuity over contrast-enhanced CT scans (9/13, 69%) and showed the extent of lesions more accurately in all cases (13/13, 100%). In nine patients, lesions had a peripheral enhancement pattern of alternating attenuation values correlating with the hyperemic rim at pathologic evaluation. On sonograms, the tumors were solid and predominantly hypoechoic. On MR, tumor signal was low on T1-weighted and high on T2-weighted images, with a low-signal halo present around many of the lesions. CT, sonographic, or MR findings of coalescent peripheral hepatic masses with capsular retraction are highly suggestive of hepatic epithelioid hemangioendothelioma.     

Single-voxel proton MR spectroscopy of nonneoplastic brain lesions suggestive of a neoplasm.

BACKGROUND AND PURPOSEMR spectroscopy is used to characterize biochemical components of normal and abnormal brain tissue. We sought to evaluate common histologic findings in a diverse group of nonneoplastic diseases in patients with in vivo MR spectroscopic profiles suggestive of a CNS neoplasm.METHODSDuring a 2-year period, 241 patients with suspected neoplastic CNS lesions detected on MR images were studied with MR spectroscopy. Of these, five patients with a nonneoplastic diagnosis were identified retrospectively; a sixth patient without tissue diagnosis was added. MR spectroscopic findings consistent with a neoplasm included elevated choline and decreased N-acetylaspartate and creatine, with or without detectable mobile lipid and lactate peaks.RESULTSThe histologic specimens in all five patients for whom tissue diagnoses were available showed significant WBC infiltrates, with both interstitial and perivascular accumulations of lymphocytes, macrophages, histiocytes, and (in one case) plasma cells. Reactive astrogliosis was also prominent in most tissue samples. This cellular immune response was an integral component of the underlying disorder in these patients, including fulminant demyelination in two patients, human herpesvirus 6 encephalitis in one patient, organizing hematoma from a small arteriovenous malformation in one patient, and inflammatory pseudotumor in one patient. Although no histologic data were available in the sixth patient, neoplasm was considered unlikely on the basis of ongoing clinical and neuroradiologic improvement without specific therapy.CONCLUSIONNonneoplastic disease processes in the CNS may elicit a reactive proliferation of cellular elements of the immune system and of glial tissue that is associated with MR spectroscopic profiles indistinguishable from CNS neoplasms with current in vivo MR spectroscopic techniques. Such false-positive findings substantiate the need for histologic examination of tissue as the standard of reference for the diagnosis of intracranial mass lesions.     

Factor analysis of medical image sequences in MR of head and neck tumors.

PURPOSETo evaluate factor analysis of medical image sequences (FAMIS), a means whereby physiologic contrast enhancement kinetics, called factors, and their spatial distribution, termed factor images, are estimated after acquisition of dynamic MR images. The method is intended to recognize and characterize the different tissue kinetics automatically.METHODSThis method was evaluated in a series of 22 patients with head and neck tumors. Eleven patients presented with a previously untreated lesion. Six were examined for tumor recurrence, previously treated by multiple therapies. Five patients had preoperative chemotherapy and underwent MR before and after chemotherapy. In all cases, MR images were correlated with surgical and pathologic data. MR examinations were performed on a 1.5-T unit with static sequences and dynamic sequences acquired after bolus injection of gadolinium and processed by FAMIS.RESULTSFAMIS was able to identify three factors representing contrast-enhancement kinetics and their associated factor images. The neoplastic component was associated with the earlier factor image, F1. Fibrosis and chemotherapy and/or radiation-induced changes were associated with the two later factors, F2 and F3. The limits of this method were highly vascularized tissues whose earlier factor was similar to that of neoplastic tissues (mucosae and salivary glands), patient motion, responsible for artifacts in FAMIS, and lesions of less than 5 mm.CONCLUSIONFAMIS of dynamic MR studies was useful for differentiating neoplastic tissue from tissue having undergone changes by chemotherapy and/or radiotherapy, but it did not improve the ability of MR to characterize neoplastic tissues in previously untreated patients.     

眶壁转移瘤的CT和MRI诊断

目的分析研究眶壁转移瘤的CT和MRI特点,提高诊断准确率.方法回顾性分析23例经手术病理证实的眶壁转移瘤的CT和MRI表现,成人组16例,儿童组7例.所有病例均行CT平扫与MR平扫和增强扫描.结果16例成年患者CT表现均为溶骨性骨质破坏和眼眶不规则肿块,9例骨质破坏区邻近的颅内可见扁平不规则肿块;16例MRI表现为骨质破坏区邻近的眼眶和颅内均可见略长T1、略长T2信号的不规则软组织影,增强后呈明显强化.7例儿童患者CT表现均为溶骨性骨质破坏和眼眶不规则肿块,其中2例可见垂直针状高密度影,3例骨质破坏区邻近的颅内可见扁平不规则软组织肿块;MRI显示7例骨质破坏区邻近的眼眶内和6例颅内可见略长T1、略长T2信号不规则的软组织影,其中1例为双侧,增强后呈明显强化;7例双侧眶骨、4例斜坡和双侧岩尖及1例双侧颞骨鳞部骨髓腔呈略长T1、略长T2信号影,增强后呈明显强化.结论眶壁转移瘤的CT和MRI表现有一些特点,有助于诊断和鉴别诊断.     

Magnetic resonance of the brain: the optimal screening technique

Magnetic resonance (MR) images and computed tomograms of 25 patients with head trauma were compared. MR proved to be superior in many ways for demonstrating extracerebral as well as intracerebral traumatic lesions. Isodense subdural hematomas, which present a diagnostic dilemma on CT images were clearly seen on MR, regardless of their varying CT densities. In a case of epidural hematoma, the dura mater was shown directly as nearly devoid of signal on MR. Direct coronal images provided excellent visualization of extracerebral collections along the peritentorial space and subtemporal area. In a patient with intracerebral hematoma, CT failed to demonstrate residual parenchymal changes in a 3-month follow-up study, but MR clearly depicted the abnormalities. The superiority of MR over CT was also well illustrated in a patient with post-traumatic osteomyelitis of the calvarium.     

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。     

Hypertrophic cranial pachymeningitis: assessment with CT and MR imaging

Three patients with diffuse idiopathic cranial pachymeningitis with predominant involvement of the tentorium and falx are reported. Progressively increasing headaches were the usual symptoms, along with ataxia and various cranial nerve palsies. CT in all cases and MR imaging in two cases detected isolated thickened dura mater. In one case, MR depicted dural involvement as a very large, hypointense area with fine hyperintense edges on T2-weighted images. Microscopic examination of thickened dura revealed extensive fibrotic tissue with a chronic inflammatory infiltrate containing lymphocytes, plasma cells, and scattered eosinophils; these findings closely paralleled the MR features. Only four cases with similar pathologies have been described, all before the advent of CT and MR. We discuss the different causes of thickened dura mater as well as the significance of the fact that dural thickening can be responsible for occlusion of the dural sinuses. Cranial pachymeningitis is a rarely reported disease that can resemble other disorders associated with tentorial thickening; CT and MR can help differentiate it from these other disorders.