血管母细胞瘤的影像学诊断

目的探讨血管母细胞瘤的影像学诊断价值。资料与方法搜集经手术病理证实的中枢神经系统血管母细胞瘤36例;回顾性分析CT和MRI表现。结果病变位于后颅凹27例,大脑半球3例,脊髓8例;其中2例为小脑内多发病变,2例为小脑及颈髓并存病变。CT表现为囊性病变边缘有软组织密度结节,MRI表现为囊性信号伴边缘灰色信号结节,可见周围流空的血管信号影,结节明显强化;脊髓病变以血管信号影为主。结论CT和MRI对向管母细朐瘤均有串付串件诊断价值．MRI优于CT扫描。     

Choroid plexus papilloma in the posterior cranial fossa: MR, CT, and angiographic findings.

In this study, we reviewed the magnetic resonance (MR, n=5), computed tomography (CT, n=3), and angiography (n=3) of six patients with pathologically confirmed choroid plexus papilloma (CPP) in the posterior cranial fossa. CPPs in the posterior cranial fossa have several features, including a propensity to arise at the foramen of Luschka with extraventricular extension, occasional peritumoral signal voids/cysts or calcification, weaker enhancement on MR or CT, and less strong tumor staining by the anterior or posterior inferior cerebellar artery or angiography.     

Spinal cord schistosomiasis: MR imaging appearance with surgical and pathologic correlation

BACKGROUND AND PURPOSE: Spinal cord involvement is a rare manifestation of schistosomiasis. We describe the MR imaging findings of spinal cord schistosomiasis in correlation with surgery and pathology. METHODS: We report eight cases of spinal cord schistosomiasis. All patients were men (mean age, 16.7 years) with neurologic manifestations who had been referred for spinal MR imaging. In all cases, spinal masses were surgically removed. MR imaging findings were correlated with surgery and pathology. RESULTS: MR imaging showed moderate expansion of the distal spinal cord in all cases. Abnormalities were isointense to cord in T1 and patchy hyperintense in T2-weighted spin-echo images (n = 8). Three forms of contrast enhancement were recognized: (1) intramedullary nodular (n = 8); (2) peripheral (n = 8); and (3) linear radicular (n = 4). Total gross surgical removal of masses by using the Cavitron ultrasonic surgical aspirator was possible in six cases. Diagnosis was established by identification of ova in histopathologic studies: Schistosoma mansoni (n = 3), S. hematobium (n = 1), and uncertain species (n = 4). Intramedullary nodular enhancement was correlated to multiple schistosomiasis microtubercles. Peripheral enhancing lesions correlated to thickened leptomeninges infested by chronic granulomatous inflammatory cells and schistosoma eggs. Linear radicular enhancement correlated with thickened resected nervous roots infested by granulomatous cells and schistosoma eggs. CONCLUSION: Multinodular intramedullary contrast enhancement of the distal cord enabled correct presumptive preoperative MR imaging diagnosis of spinal schistosomiasis in three cases. Accurate diagnosis, through recognition of its MR imaging appearance, allows early treatment and better prognosis of spinal cord schistosomiasis.     

MR imaging of syringomyelia and hydromyelia

The relative effectiveness of plain computed tomography (CT), metrizamide CT, conventional myelography, and magnetic resonance (MR) imaging was compared for the examination of cystic spinal cord lesions. Intramedullary cavities in 18 patients were demonstrated by MR imaging: cavities were uncomplicated in 13 patients, associated with spinal tumors in two, and studied after occipital craniectomy for treatment of Chiari malformation and syringomyelia in two. Cavities were shown by MR imaging in all enlarged spinal cords, but a cavity was shown in only one of four small cords. The rostral limits of the cavities were demonstrated better than were the caudal extensions. Ventricular communication was not demonstrated. Chiari malformation was shown only in cavities that did not involve the medulla. Syringes associated with tumor were indistinguishable from uncomplicated cavities, but the tumor had abnormal signal on long spin-echo sequences in two cases. Cystic cord tumor (one case) had an inhomogeneous appearance. Caudal displacement of the cerebellar hemisphere through the surgical defect associated with compression of the fourth ventricle was shown in two cases after posterior fossa craniectomy. Thirteen patients were studied with metrizamide CT also. MR imaging proved to be as accurate as metrizamide CT in the diagnosis of intramedullary cavities that result in spinal cord enlargement, but it was less sensitive in detecting cavities within normal-sized or diminished spinal cords. It had the advantage that tumor tissue could be distinguished from associated syrinx cavities by differences in signal characteristics; and cerebellar ectopia was evaluated easily on sagittal MR views.     

Spinal epidural cavernous hemangioma: MR findings

PURPOSE: Cavernous hemangiomas with a spinal epidural location are very uncommon vascular tumors in contrast to those in the vertebral body. The purpose of this study was to describe the radiologic findings, focusing on the MR studies, of spinal epidural cavernous hemangiomas. METHOD: Five pathologically proven cases of spinal epidural cavernous hemangioma were retrospectively reviewed. MR (n = 5) and CT (n = 1) were evaluated. RESULTS: The level was thoracic (n = 4) or lumbosacral (n = 1). The mass was located in the epidural space and showed paravertebral extension in all cases. It showed a lobulated contour in all cases and encircled the spinal cord partially with a larger posterior (n = 3) or anterior (n = 1) component in four cases. In all cases, the mass showed high signal intensity on T2-weighted images and homogeneous, strong enhancement. Adjacent bony erosion (n = 5) and intervertebral neural foraminal widening (n = 4) were common. CONCLUSION: Spinal epidural cavernous hemangioma shows characteristic MR findings of a lobulated contoured epidural mass partially encircling the spinal cord with a larger posterior component in the spinal canal, high signal intensity on T2-weighted images, and homogeneous, strong enhancement.     

脊髓成血管细胞瘤的MR诊断

目的分析脊髓成血管细胞瘤的ＭＲ表现。方法 １６例经手术病理证实的脊髓成血管细胞瘤患者,男６例,女１０例,年龄１５￣５７岁,平均年龄３０．７岁,全部行ＭＲ检查。结果 在１６例患者中,出现多发或合并有小脑成血管细胞瘤的患者有８例,共发现脊髓成血管细胞瘤２３个。发生于颈段者１４个,其中９例位于Ｃ３水平以上,发生在胸髓者９个。１６个肿瘤位于脊髓背侧,４个肿瘤于脊髓中央,位于脊髓一侧,腹侧和髓外的肿瘤各１个     

Gd-DTPA-enhanced MR of suspected spinal multiple sclerosis

A prospective study was undertaken to evaluate the potential of Gd-DTPA-enhanced MR to differentiate active from inactive demyelinating lesions of the cervical spinal cord. Five patients with elongated high-signal-intensity lesions in the cervical cord on long TR/TE spin-echo MR images and a clinical suspicion of demyelinating disease had MR before and after IV Gd-DTPA. Delayed contrast enhancement (after 45-60 min) of the lesions was seen on short TR/TE images in two patients with clinically active disease, but no enhancement could be detected in three patients with stable disease. The patients with active disease underwent repeated MR examinations until the enhancement disappeared. The decrease in Gd-DTPA enhancement paralleled a decrease in clinical signs and symptoms of cervical myelopathy. MR is useful in evaluating patients suspected of having demyelinating disease. The MR finding of asymptomatic lesions in the brain lends support to the diagnosis of multiple sclerosis. Other possible causes of myelopathy, such as spinal cord compression and intramedullary tumor, can be excluded with the use of MR.     

MR features of diseases involving bilateral middle cerebellar peduncles

BACKGROUND AND PURPOSE: Distribution of lesions or involvement of specific anatomic sites can suggest the diagnosis of disease. The purpose of this study was to investigate what diseases affect both middle cerebellar peduncles (MCPs) and to evaluate other MR features for differential diagnosis.METHODS: MR findings of 27 patients (14 male and 13 female; age range, 4–77 years [mean, 48.5 years]) with bilateral MCP lesions were retrospectively studied.RESULTS: Neurodegenerative diseases were the most frequent diagnoses (n = 11 [41%]: sporadic olivopontocerebellar atrophy, eight; Shy-Drager syndrome, one; spinocerebellar ataxia, two). Also included were metabolic diseases (n = 6 [22%]: adrenoleukodystrophy, two; Wilson disease, two; cirrhosis of the liver, one; and hypoglycemia, one); cerebrovascular diseases, including posterior reversible encephalopathy syndrome (n = 3 [11%]: infarction, one; hypertensive encephalopathy, one; cyclosporin-A encephalopathy, one), demyelinating and inflammatory diseases (n = 4 [15%]: multiple sclerosis, one; acute disseminated encephalomyelitis, one; Behçet disease, one; and HIV encephalopathy, one), and neoplasms (n = 3 [11%]: lymphoma, one; glioma, one; meningeal carcinomatosis, one). All patients showed symmetrical T2 hyperintensity in both MCPs, except for one with malignant lymphoma. Marked atrophy in the posterior fossa was characteristically seen in neurodegenerative diseases. Enlargement of the pons was observed in hypertensive encephalopathy and neoplasms but absent in meningeal carcinomatosis. Lesions were restricted in the posterior fossa in eight patients with neurodegenerative diseases and one with brain stem glioma. Other patients had supratentorial lesions.CONCLUSION: Symmetricity of MCP lesions, morphologic change of the posterior fossa structures, and distribution of other lesions are helpful in the differential diagnosis.

MR imaging is the most sensitive imaging technique to depict brain lesions as altered signal intensities. Most of the lesions are demonstrated as hyperintensities on T2-weighted MR images, and the signal intensity itself is nonspecific. Characteristic distribution of lesions or involvement of specific anatomic sites, however, can suggest the diagnosis or narrow the differential diagnosis.The middle cerebellar peduncle (MCP) consists of the transversely coursing pontocerebellar fibers that arch across the midline and gather on each side (1). The MCPs can be evaluated by routine MR examination, and normal MCPs show homogeneous white matter signal intensity. Bilateral involvement of the MCPs is well known in olivopontocerebellar atrophy (OPCA) (2) but is relatively rare in other diseases. We retrospectively reviewed the MR findings and the clinical charts of the patients with bilateral MCP lesions to investigate what disorders affect both MCPs and to evaluate other MR features for differential diagnosis. A literature review on bilateral involvement of MCPs is also presented.     

Spinal intradural extramedullary capillary hemangioma: MR imaging findings

SUMMARY: Spinal intradural extramedullary capillary hemangiomas are extremely rare. We present the MR imaging and histologic findings in three patients with this abnormality. The three patients were men who had symptoms of either myelopathy (n = 2) or radiculopathy (n = 1). The tumors were well demarcated, 1.5-2.0 cm in diameter, and were located at the posterior or posterolateral portion of the thecal sac (one at the L1 level and the other two at the midthoracic level). On MR images, the tumor showed isointensity relative to the spinal cord on T1-weighted images, hyperintensity on T2-weighted images, and strong homogeneous enhancement on contrast-enhanced T1-weighted images in all three patients. In two patients, the dural tail sign was observed. Capillary hemangioma should be included in the differential diagnosis of a spinal intradural extramedullary tumor.     

MR findings in AIDS-associated myelopathy.

BACKGROUND AND PURPOSE: The most common cause of spinal cord disease among patients with AIDS or those infected with HIV-1 is AIDS-associated myelopathy. The purpose of this study was to determine the MR characteristics of the spinal cord in this patient population and to correlate these findings with the clinical severity of myelopathy. METHODS: MR images of the spinal cord in 21 patients with documented HIV-1 infection or AIDS and a clinical diagnosis of AIDS-associated myelopathy were assessed retrospectively for atrophy, intrinsic signal abnormality, and abnormal enhancement. The clinical severity of myelopathy was graded by a neurologist on the basis of physical examination, and a qualitative correlation was made with the MR findings. RESULTS: MR findings were abnormal in 18 of the 21 patients. The most common feature was spinal cord atrophy (n = 15), typically involving the thoracic cord with or without cervical cord involvement, followed by intrinsic cord signal abnormality (n = 6), and normal-appearing cord (n = 3). Three patients had both cord atrophy and intrinsic cord signal abnormality. The cord signal abnormality was diffuse, without predilection for any specific distribution pattern. Enhancement was not seen in any of the 10 patients who received intravenous contrast material. Only one of 16 patients with moderate to severe myelopathy had normal MR findings, as compared with two of five patients with mild myelopathy. CONCLUSION: MR findings in the spinal cord are abnormal in the majority of patients with AIDS-associated myelopathy, typically showing spinal cord atrophy, with or without intrinsic cord signal abnormality. Patients with moderate to severe myelopathy have an increased frequency of spinal cord abnormalities, but a definite correlation between clinical severity of myelopathy and extent of MR abnormalities remains to be established.     

Acute cervical spine trauma: evaluation with 1.5-T MR imaging

Twenty-one patients with acute neurologic deficits following cervical spine trauma were evaluated with magnetic resonance (MR) imaging (n = 21), computed tomography enhanced with intrathecal contrast material (CT myelography) (n = 18), myelography (n = 13), cervical spine radiography (n = 21), and intraoperative sonography (n = 7). MR imaging proved superior to other modalities in demonstrating parenchymal spinal cord injuries and cervical intervertebral disk herniation. Although both T1- and T2-weighted studies appear necessary to evaluate the anatomic relationship of the spinal cord, thecal space, intervertebral disks, and surrounding osseous and ligamentous structures, T2-weighted sequences were more sensitive than T1-weighted studies for detection of spinal cord injury. CT myelography was superior to MR imaging in demonstrating cervical spine fractures. In most cases, myelography revealed no information that was not apparent from both CT and MR imaging studies. Preliminary experience with MR imaging of acute cervical spine trauma suggests that it should be the study of choice in symptomatic patients who are otherwise clinically stable. CT may still be required in selected patients to evaluate complex fractures.     

Spinal subdural enhancement after suboccipital craniectomy.

PURPOSETo characterize transient intraspinal subdural enhancement (potentially mimicking the subarachnoid spread of tumor) seen on MR images in some children after suboccipital craniectomy for posterior fossa tumor resection.METHODSRadiologic and medical records of 10 consecutive children who had MR imaging for spinal staging after resection of posterior fossa tumor during a 9-month period were reviewed retrospectively. In addition, one case with similar findings of intraspinal enhancement on spinal staging MR images obtained at another institution was included in the review.RESULTSIntraspinal enhancement thought to be subdural was seen in four of 10 patients undergoing spinal staging MR imaging 6 to 12 days after surgery. In these four patients, MR studies 50 to 18 days later, without intervening treatment, showed resolution of the abnormal enhancement. A fifth patient (from another institution) with similar intraspinal enhancement underwent CT myelography 4 days later, which showed no subarachnoid lesions. No metastases have developed in any of these five patients during the 2.5- to 3.5-year follow-up period. conclusions: From analysis of the MR appearance and on the basis of prior myelographic experience, we suggest an extraarachnoid, probably subdural, location of this enhancement. Awareness of this phenomenon will reduce the rate of false-positive diagnoses of metastatic disease. Preoperative spinal staging should be considered for patients undergoing suboccipital craniectomy.     

Magnetic resonance study of lesions of the cervical spinal cord in multiple sclerosis

Lesions consistent with demyelinating plaques were retrospectively identified in the cervical spinal cord of 15/49 patients (31%) with multiple sclerosis examined with cranial and cervical MR imaging. The lesions appeared as hyperintense areas on proton-density and T2-weighted images. Clinical signs and symptoms suggestive of spinal cord location of the demyelinating plaques were observed in 14 of the 15 patients presenting with spinal cord lesions at MR, and also in 11 of the 34 patients with negative MR findings. In 2 patients the cervical lesion was not associated with brain lesions at MR, while in 1 patient it was associated with medullary dilatation. Serial MRs revealed disappearance of the cervical hyperintense area in both patients, and reduction in medullary volume in the latter. Therefore, MR imaging of the cervical spinal cord is suggested as an useful examination in patients with suspected multiple sclerosis, particularly in those presenting with clinical signs and symptoms suggestive of spinal cord involvement.     

中枢神经系统脱髓鞘性假瘤的MRI表现

目的 描述中枢神经系统脱髓鞘性假瘤的MRI表现，探讨该病变的病理学改变特征以及MRI诊断价值和限度。方法 对7例经手术病理证实及1例经临床证实的中枢神经系统脱髓鞘性假瘤进行了MR检查，对其MR影像学表现特征进行了回顾性分析。结果 MRI显示8例病变均表现为局限性肿块，邻近未见伴有多发病灶；5例呈均匀长T1信号，2例呈不均匀长T1信号，1例呈短T1及长T1混杂信号；5例呈均匀长T2信号，3例呈不均匀长T2信号；7例经钆喷替酸葡甲胺（Gd-DTPA)增强者病灶均有明显强化，其中1例左额顶叶病灶强化后有垂直于侧脑室分布的倾向，1例颈段脊髓病灶可见以背侧白质为主的强化；MR复查未见病变复发征象，其中1例激素治疗后病变逐渐缩小。结论 中枢神经系统脱髓鞘性假瘤的临床和影像学诊断较困难，MR检查常将本病误诊为肿瘤。诊断时若能认真分析临床病史并仔细观察MRI表现（特别是增强MRI表现），则有可能提出本病的诊断，此时可以先使用激素试验治疗，以避免手术或放射治疗造成的严重损伤。     

Childhood scoliosis: MR imaging

The spinal cords of 28 scoliosis patients between the ages of 1 month and 17 years were examined with magnetic resonance (MR) imaging. Complete visualization was obtained in all cases. In 15 patients (53%) neuropathologic abnormalities demonstrated by MR imaging significantly affected their clinical course, including tethered cords (n = 7), syringomyelia (n = 5), Arnold-Chiari I malformation (n = 4), spinal cord tumors (n = 2), Arnold-Chiari II malformation (n = 3), and diastematomyelia (n = 1). The advantages of MR imaging in the evaluation of the scoliotic spine in children include a high sensitivity for the occult conditions associated with scoliosis, good anatomic demonstration of the cord, and absence of bone artifacts. MR imaging is recommended as a primary imaging modality in scoliosis, following conventional radiography.     

Acute spontaneous spinal epidural hematomas.

BACKGROUND AND PURPOSE: Although previous reports have characterized MR imaging features of spinal epidural hematomas (EDH), few cases have been reported during the acute or hyperacute phase within the first 48 hours. Our goal in this investigation was to correlate the MR imaging features of acute (< or =48 hours) spontaneous EDH with clinical management and outcome. METHODS: Eight patients with acute spontaneous EDH (five men and three women; age range, 31-81 years) underwent MR imaging at 1.5 T (T1-weighted, n = 8; T1-weighted after the administration of 0.1 mmol/kg contrast material, n = 6; T2-weighted, n = 8; and T2-weighted, n = 4). The interval from symptom onset to hospital admission ranged from immediate to 5 days. Two neuroradiologists reviewed the MR images for signal characteristics, contrast enhancement, and cord compression. Treatment and clinical outcome were correlated with the imaging findings. RESULTS: The EDH were located in the cervical (n = 3), cervicothoracic (n = 2), thoracolumbar (n = 2), and lumbar (n = 1) regions. On T1-weighted images, the signal intensity of the EDH was isointense to spinal cord in five cases, hyperintense in two cases, and hypointense in one case and did not correlate with time to imaging. Isointensity on T1-weighted images persisted for 5 days in one case. On T2-weighted images, all EDHs were hyperintense with focal, heterogeneous hypointensity. Cord compression was severe in six patients, moderate in one patient, and minimal in one patient. Four cases were treated conservatively with complete resolution or improvement of symptoms within 1 to 3 weeks. CONCLUSION: MR imaging findings were useful in establishing the diagnosis of EDH but did not influence management or predict outcome in this series. Heterogeneous hyperintensity to cord with focal hypointensity on T2-weighted images should suggest the diagnosis of acute spinal EDH. Severity of neurologic impairment had the greatest impact on management and outcome. Nonoperative treatment may be successful in cases with minimal neurologic deficits, despite cord compression revealed by MR imaging.     

MR-pathologic comparisons of wallerian degeneration in spinal cord injury.

PURPOSETo describe the MR manifestations and temporal course of wallerian degeneration that occurs above and below a spinal cord injury, and to compare the MR findings with postmortem histopathology.METHODTwenty-four postmortem spinal cords from patients with cervical (n = 14), thoracic (n = 6), and lumbar (n = 4) cord injuries were studied with axial T1- and T2-weighted spin-echo MR imaging. Injury-to-death intervals varied from 8 days to 23 years. The images were examined for alteration of signal above and below the injury site. Histologic studies of these cords with axon, myelin, and connective tissue stains were performed at levels equivalent to the MR sections. Immunohistochemical analysis using antibodies to glial fibrillary acetic protein was also performed on 19 cords. Pathologic-imaging comparisons were made.RESULTSMR images showed increased signal intensity in the dorsal columns above the injury level and in the lateral corticospinal tracts below the injury level in all cases in which cord injury had occurred 7 or more weeks before death. In early postinjury survival times (8 days and 12 days) MR findings were normal; histologically there was early wallerian degeneration in only the dorsal columns at 8 days and in both the lateral and dorsal columns at 12 days. MR showed wallerian degeneration in all cases examined at 7 weeks after injury and thereafter.CONCLUSIONSWallerian degeneration was demonstrated by histology and MR in all specimens in which the injury-to-death interval was greater than 7 weeks. Recognition of wallerian degeneration on MR allows complete analysis of the injury, explains abnormal MR signals at sites remote from the epicenter of the injury, and may be useful in the future in the timing and planning of therapeutic interventions.     

MR imaging of the spinal cord: current status and future advances.

The advent of MR imaging has dramatically altered the evaluation of suspected myelopathy. MR is far less invasive than traditional imaging techniques and often offers a degree of understanding of an abnormality not previously possible. These achievements have closely followed recent technologic advances, such as the development of contrast agents and the introduction of sequences that permit a reduction in both imaging time and artifacts. The current role of MR in the imaging of spinal cord disorders, including intramedullary tumors, infectious and inflammatory myelitis, demyelinating diseases, vascular lesions, trauma, syringomyelia/hydromyelia, and neurodegenerative disorders, is reviewed. While further improvements will undoubtedly occur, the field of spinal MR imaging appears to be entering a maturing phase.     

Diffuse lesions in the CNS revealed by MR imaging in a case of Whipple disease

SUMMARY: We report a case of Whipple disease involving the brain, optic chiasm, posterior fossa, and spinal cord. We evaluate the role of MR imaging for initial evaluation and for long-term follow-up of Whipple disease involving the CNS. We also discuss the semiologic characteristics of the lesions.     

后颅窝脑实质出血穿入脑室系统的CT研究

目的：探讨后颅窝出血经脑室系统弥散的CT表现及临床意义。方法：回顾性分析23例后颅窝出血的CT检查资料。结果：后颅窝出血经脑室系统弥散者12例,其中第四脑室积血12例,第三脑室积血9例,侧脑室积血8例。后颅窝出血穿入脑室与血肿体积有明显关系（P＜0．01）,第三脑室扩大在脑室积血与非积血者之间有显著差异（P＜0．01）。结论：后颅窝出血可穿入第四脑室并经脑室系统弥散。CT检查对于发现病因及制定治疗方案具有重要意义。