Magnetic resonance imaging of intraspinal cystic lesions: a pictorial review

Magnetic resonance imaging is the imaging modality of choice for the evaluation of diseases of the spinal cord and its coverings primarily because of improved lesion detection and characterization. The differentiation of intramedullary pathologic conditions (arising within the spinal cord) from extramedullary lesions (lying either within the thecal sac (intradural) or outside it (extradural) is usually straightforward. Although many lesions may occur in more than one compartment or may extend to involve more than one compartment simultaneously, accurate positioning of a detected lesion within the spinal canal and the assessment of its signal characteristics may help differentiate many of the more commonly encountered lesions and aid preoperative diagnosis. This pictorial review discusses the imaging findings and distinguishing features of a variety of intramedullary and extramedullary intraspinal cystic lesions with the use of magnetic resonance imaging. The imaging appearances are correlated with histologic findings where available.     

Primary tumors and other masses of the cerebellum and fourth ventricle: Differential diagnosis by computed tomography

Summary Seventy-three tumors of the cerebellum and fourth ventricle were analyzed by computed tomography to establish criteria for identifying the location and histology of the tumor. Brain stem tumors and metastases were excluded from the study. Tumors within the fourth ventricle are usually central in location, have a lucent halo and show no evidence of a separate, displaced fourth ventricle. Tumors within the cerebellar hemispheres are usually eccentric in location, lack a halo and displace the fourth ventricle. Ependymomas may be distinguished from classical medulloblastomas because they calcify more frequently, have small lucent zones, and extend into the cisterns of the cerebellopontine angles. Hemangioblastomas may be distinguished from cerebellar astrocytomas because they are usually not calcified, are smaller than astrocytomas and often exhibit central necrosis of smaller tumors than astrocytomas. In many cases, cerebellar sarcomas (desmoplastic medulloblastomas) may be distinguished from astrocytomas by their homogeneously increased attenuation homogeneous contrast enhancement and lack of calcification. In this series, all intraventricular lesions with ring blushes after contrast enhancement, and all but one intraventricular lesion with well defined lucencies, were ependymomas. All calcified extraventricular lesions were astrocytomas. No medulloblastoma, ependymoma or cerebellar sarcoma demonstrated homogeneously decreased attenuation and none was a predominantly cystic mass. The criteria presented tend to localize and identify accurately the vast majority of intraventricular and hemispheric masses, in the posterior fossa.Presented at the 14th Annual Meeting of the American Society of Neuroradiology, Atlanta, Georgia, May 18–24, 1976     

Pädiatrische intraspinale Neoplasien

With an overall incidence of 10?% of all central nervous system tumors, spinal tumors are relatively rare in children. The majority of these tumors are astrocytomas and ependymomas (70?%) followed by rare non-glial tumor entities, such as gangliogliomas. They can be differentiated into intramedullary, extramedullary intradural and extramedullary extradural tumors according to their occurrence within the anatomical intraspinal compartments. The clinical presentation is generally unspecific. Longer lasting back pain or a gradually worsening scoliosis are often the first signs of the disease. Neurological deficits, such as gait disturbances and paresis often occur after a time delay. In rare cases increased intracranial pressure has been reported. Knowledge concerning potential organ manifestations, resulting complications and typical radiological presentation, especially in magnetic resonance imaging are mandatory for adequate diagnosis and treatment of affected patients.     

Myxopapillary ependymoma of the ischioanal fossa

Ependymomas outside the confines of the cranium and spinal cord are rare. Direct extension into the soft tissues of the sacrococcygeal area may occur from a primary ependymoma of the spinal cord, cauda equina or filum terminale. Alternatively they may occur as a primary pre-sacral, pelvic and abdominal tumour, or as a primary tumour of the skin and subcutaneous tissue of the sacrococcygeal area without any demonstrable connection with the spinal cord. The Authors report a case of myxopapillary ependymoma of the ischioanal fossa, demonstrated by MRI. To our knowledge, our case is the first lesion reported at this site.     

Parasagittal ependymoma resembling falcine meningioma.

Presentation, diagnosis, and management of an unusual parasagittal ependymoma, radiographically resembling a falcine meningioma, are described. Despite its radiographic appearance, pathologic evaluation revealed classic features of an ependymoma. The radiographic and pathologic characteristics of this unusual lesion are briefly examined, and the literature is reviewed. Although extraaxial ependymomas are rare, they should be considered in the radiographic differential diagnosis of dural-based lesions, especially for patients within the first 3 decades of life.     

Supratentorial ependymomas: computed tomographic and pathologic correlations

Of a total of 52 cases of ependymomas, 38 were intracranial, with 15 being supratentorial and 23 infratentorial. Pre- and postoperative computed tomographic scans were correlated with surgical pathologic findings in four cases of supratentorial ependymomas. Pathologic specimens were analyzed from another four cases for which only postoperative scans were available. Seven cases had no computed tomographic studies, but pathology reports were available. Common computed tomography findings for these tumors included para- or intraventricular location, one or more cystic areas within the tumor, and calcifications within the lesion or around its periphery. Proven subependymal spread of tumor was evident by computed tomography in one case. Mixing of ependymoma with oligodendroglioma was present in four cases and with both oligodendroglioma and astrocytoma in two cases. Microscopic calcifications were more frequently seen in ependymomas that were mixed with oligodendroglioma.     

CT and MRI in the evaluation of extraspinal sciatica

Sciatica is the most frequently encountered symptom in neurosurgical practice and is observed in 40% of adults at some point in their lives. It is described as pain of the hip and the lower extremity secondary to pathologies affecting the sciatic nerve within its intraspinal or extraspinal course. The most frequent cause is a herniating lumbar disc pressing on the neural roots. Extraspinal causes of sciatic pain are usually overlooked because they are extremely rare and due to intraspinal causes (lumbar spinal stenosis, facet joint osteoarthritis, fracture, and tumors of the spinal cord and spinal column) being the main consideration. Early diagnosis of sciatica significantly improves the likelihood of relieving symptoms, as well as avoiding any additional neurologic injury and unnecessary surgery. We evaluate histolopathologically confirmed extraspinal causes of sciatica cases, accompanied by their presented computed tomography and/or magnetic resonance imaging findings.     

Magnetic resonance imaging of spinal trauma

A retrospective series of 118 magnetic resonance examinations of 110 patients who had sustained previous spinal trauma is reported. Examinations performed within 3 weeks of trauma showed extraspinal soft tissue (including ligamentous) injury in 48% and intraspinal lesions in 61% (mostly consisting of extradural haematoma and spinal cord contusion). In examinations performed more than 3 weeks after injury intraspinal abnormalities were shown in 51% and these represented spinal cord compression, atrophy, myelomalacia and syringohydromyelia. Magnetic resonance imaging has the unique capability of displaying non-invasively the late sequelae of spinal trauma permitting simultaneous evaluation of the extra-spinal soft tissues, vertebral column and spinal cord. It is therefore recommended as the technique of choice in the investigation of patients who have sustained previous spinal injury, particularly those with neurological deficit. In the acute phase potentially remediable causes of neurological impairment such as disc herniation or extradural haematoma can be identified. Signal changes in the cord may allow the prognosis for neurological recovery to be established. In the later stages sequelae such as cord atrophy, myelomalacia and syringohydromyelia are accurately identified and surgical therapy may be guided, where appropriate.     

Multiple occult vascular malformations of the brain and spinal cord: MRI diagnosis

Summary We report a patient with multiple angiographically occult vascular malformations in the brain and spine. Magnetic resonance imaging showed multiple lesions in brain and spine with hypointense areas on both T1 and T2-weighted images. These hypointense areas are usually secondary to hemosiderin deposits consistent with remote bleeding in the lesions. We conclude that when magnetic resonance reveals an intraspinal lesion with signal intensity characteristics consistent with a vascular malformation, an examination of the brain should be performed to rule out associated intracranial lesions. The finding of multiple lesions in the brain with identical signal intensity characteristics reinforces the diagnosis of vascular malformation.     

Magnetic Resonance Imaging Characteristics of Primary Intraspinal Peripheral Primitive Neuroectodermal Tumour

Purpose

The purpose of our study was to describe the salient magnetic resonance imaging (MRI) findings in primary intraspinal peripheral primitive neuroectodermal tumour (PNET).

Methods

A retrospective review of the clinical and MRI images of 7 pathologically proven cases of intraspinal peripheral PNETs was performed. The various parameters, such as vertebral level of involvement; tumour location, size, focality, and margin; signal intensity of the lesion; the presence of hemorrhage or calcification; any signal voids; assessment of the adjacent cord for cord compression; cord dilatation; the presence of paraspinal tissue mass; or vertebral or other bony changes, were analysed.

Results

All 7 patients had lesions in the thoracolumbar region. Three patients had extradural lesions, 4 had intradural extramedullary lesions, and none had intramedullary lesions. Six lesions were well circumscribed. Only 1 patient had multifocal involvement. All lesions were of hypointense or isointense signal on T1-weighted imaging, whereas all but one were hyperintense on T2-weighted imaging. Lesions enhanced heterogeneously except 1 intradural extramedullary lesion, which enhanced homogeneously. A paraspinal mass was noticed in 2 patients. Vertebral collapse was present in 1 patients.

Conclusion

Intraspinal peripheral PNETs are rare spinal tumours. Although imaging characteristics are not specific, a focal circumscribed lesion in a young individual at the intramedullary, extramedullary intradural, or extradural spinal location that shows hypointense and hyperintense signal on T1- and T2-weighted images, respectively, requires PNET to be considered in the differentials.     

Intraspinal primitive neuroectodermal tumor: Imaging findings in six cases

Purpose

To retrospectively review CT and MRI findings in a series of six intraspinal primitive neuroectoderal tumors and to find out their radiological features.

Methods

CT and MRI of six patients with surgically and pathologically proved intraspinal primitive neuroectoderal tumor were retrospectively reviewed. The tumor location, morphological features, signal intensity, calcification, contrast enhancement characteristics, involvement of paraspinal soft tissues and adjacent bony structures were assessed.

Results

Of six patients, four had extradural lesions and two had intradural, extramedullary lesions. Most lesions were well defined and manifested heterogeneous iso- or hypo-intense signal on T1-weighted imaging and hyper-intense signal on T2-weighted imaging and moderate attenuation on CT, and were heterogeneously enhanced after contrast enhancement. The lesion extending through the intervertebral foramen with a large paraspinal soft tissue mass formed was found in four patients and vertebral bone involvement was seen in four patients.

Conclusions

Although imaging findings are not specific of intraspinal primitive neuroectoderal tumor, this diagnosis could be suggested when MR imaging depicts an intradural, extramedullary or extradural large well-circumscribed mass which extends out from intervertebral foramen and invades paraspinal soft tissues or vertebral bones in a young patient.     

Spinal intradural tumors

Spinal intradural tumors are uncommon lesions but may cause significant morbidity. In establishing the differential diagnosis for a spinal lesion, location, age, and the patient's clinical presentation are important. Magnetic resonance imaging plays a central role in the visualization of spinal tumors, easily allowing tumors to be classified as extradural, intradural extramedullary, or intramedullary which is very useful in tumor characterization. We describe intradural tumors; the majority is extramedullary, with nerve sheath tumors being the most frequent. Intramedullary tumors are uncommon spinal tumors. Ependymomas and astrocytomas comprise the majority of this group. Typical imaging features of both intradural extramedullary and intramedullary tumors are described.     

Meningioma of the scapula

Meningiomas account for approximately 15% of all intracranial tumors and are the most common non-glial primary tumors of the central nervous system. Most meningiomas are benign neoplasms with characteristic imaging features. Primary extradural meningiomas account for only 1–2% of all meningiomas. They must be differentiated from intradural meningiomas with secondary extradural extension and/or metastases. The vast majority of extradural meningiomas are found in the skull or in the head and neck region. We report on an extremely rare case of primary extradural meningioma that was located in the scapula. The lesion was resected. Radiographic findings and pathologic features are discussed. To the best of our knowledge, this form of presentation of an extradural meningioma has not been previously described.     

椎管内淋巴管瘤的影像学表现(附3例报告并文献复习)

目的探讨椎管内淋巴管瘤的影像特征。方法报道3例椎管内淋管瘤并参考相关文献分析其影像特点。结果2例病变位于骶管,1例位于腰段椎管。MR均表现为内有分隔的囊性病变。结论椎管内硬膜外有分隔的囊性病变可以提示淋巴管瘤的诊断。CT对椎管内淋巴管瘤的诊断帮助不大,MR对椎管内淋巴管瘤的诊断价值较大。     

骨嗜酸性肉芽肿X线诊断的若干问题

125 eosinophilic granulomas of the bone in 61 cases were reported. The radiologic manifestations may be summarized as follows: (1) Multiple lesions may occur with vertebra plana; (2) Epiphyseal lesion may be primary or secondarily involved by extension from metaphyseal lesion; (3) Metaphyseal lesion usually presents as an eccentric cystic area or central oval area of lucency; (4) The diaphyseal lesion manifests a "hole within hole" appearance; (5) The tarsal bone may exhibit a "bone within bone" sign; (6) Periosteal Codman triangle may be present.     

MR imaging of intraspinal tumors—Capability in histological differentiation and compartmentalization of extramedullary tumors

Summary Magnetic resonance (MR) images of 29 consecutive patients with intraspinal neoplasms (9 intramedullary tumors, 20 extramedullary tumors) were reviewed to evaluated the utility of MR imaging in distinguishing the intraspinal compartmental localisation and signal characteristics of each lesion. Compartment and histology of all neoplasms were surgically proven. MR correctly assigned one of three compartments to all lesions, 9 intramedullary, 14 intradural extramedullary (6 schwannomas, 3 neurofibromas, 5 meningiomas), and 6 extradural (3 schwannomas, 1 meningioma, 1 cavernous hemangioma, 1 metastatic renal cell carcinoma). All intramedullary tumors showed swelling of the spinal cord itself. In all five extradural tumors a low intensity band was visualized between the spinal cord and tumor. On the other hand, a low intensity band was demonstrated in no cases with intradural tumors. Visualization of this low intensity band is important in differentiating extradural from intradural-extramedullary lesions. We call this low intensity band, the extradural sign. Signal intensity of intradural tumors varied with histology. In extramedullary tumors, signal intensity of schwannomas was similar to that of the cerebrospinal fluid (CSF) both on T1 weighted (inversion recovery) and T2 weighted spin echo (SE) images. On the other hand, meningiomas tended to be isointense to the spinal cord on both T1 and T2 weighted SE images. We found relatively reliable signal characteristics to discriminate meningioma from schwannoma.     

Imaging of tumors of the spine and spinal cord

Imaging of the spine and spinal cord has traditionally been accomplished with plain radiography, myelography, and CT. Recently, MR imaging has become the technique of choice in the assessment of lesions of the spine and spinal cord. MR imaging provides accurate localization of intramedullary, intradural extramedullary, and extradural tumors. Ependymomas and low-grade astrocytomas are the most common intramedullary tumors. MR imaging findings are distinguishable by the delineation and size of the lesion, and the signal intensity on T2-weighted images. Other less common tumors include malignant astrocytomas, hemangioblastomas, and intramedullary metastasis. Numerous foci of high-velocity signal loss are seen in the hemangioblastomas. Metastasis, meningiomas, and schwannomas are the most common intradural extramedullary tumors. Meningiomas are characterized by dural enhancement on postcontrast T1-weighted images. Schwannomas and neurofibromas often erode bony structures and appear to be dumbbell-shaped. Epidural metastasis accounts for the majority of extradural tumors. Primary malignant extradural tumors include lymphomas, chordomas, and so on. The most common primary benign extradural tumor is hemangioma, which often appears to be hyperintense on both T1-weighted and T2-weighted images. Intramedullary non-neoplastic lesions include demyelinating, vascular, and infectious diseases. Diffuse, peripheral, or speckled contrast enhancement, and lack of contrast enhancement may suggest non-neoplastic lesions.