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.     

MR imaging of spinal neurofibromatosis

The MR findings in 7 patients with neurofibromatosis involving the spine were evaluated. Six patients had paraspinal tumors at multiple levels. In 4 they were bilateral. Five patients had multiple intraspinal lesions, frequently with growth through the neural foramen. In one patient paraspinal tumors were found in the lumbar sacral plexus and in another bony dysplasia and meningoceles but no tumors were disclosed. In 2 patients the lesions were associated with bilateral acoustic neuromas and multiple intracranial meningeomas. In one of these a spinal meningeoma with signal characteristics close to spinal cord was found. The other tumors had a signal that was equal to or slightly lower than the spinal cord and slightly higher than muscle on T1-weighted images. On T2-weighted images the tumors had a markedly increased signal compared to surrounding tissue. In 3 patients with tumors larger than 4 cm the signal intensity was inhomogeneous with decreased signal in the center on T2-weighted images, indicating the presence of increased fibrous tissue. Gadolinium-DTPA was given to one patient with marked increase in intensity of small tumors on T1-weighted images. The study shows that MR imaging is the modality of choice for evaluating most aspects of spinal and paraspinal neurofibromatosis.     

Intradural schwannomas of the spine: MR findings with emphasis on contrast-enhancement characteristics.

Intradural extramedullary schwannomas are nerve sheath neoplasms that consist of focal proliferations of Schwann cells involving a spinal nerve. We reviewed the MR findings in seven patients with pathologically proved intradural schwannomas. The contrast-enhancement characteristics on MR images were determined and compared with the histologic features of the tumor. Six lesions were variably hyperintense on T2-weighted images and one was uniformly hypointense compared with the signal intensity of the spinal cord. Signal on T1-weighted images ranged from hypointense to isointense. All seven tumors showed heterogeneous enhancement; in five, the enhancement involved only the periphery of the lesion. The pattern of enhancement did not correlate with the signal characteristics noted on unenhanced T1- and T2-weighted images. Pathologically, hyaline thickening of vessel walls and cyst formation were prevalent in the peripherally enhancing lesions. However, enhancement did not correlate with the relative proportion of Antoni type A and type B tissue. Recognition of the MR characteristics of intradural extramedullary schwannomas may be helpful in the differential diagnosis of spinal tumors. In particular, peripheral contrast enhancement of an intradural extramedullary tumor on MR images should suggest the diagnosis of schwannoma.     

Spinal intradural capillary hemangioma: MR findings

We report a case of a spinal intradural capillary hemangioma. On MR images, a well-circumscribed intradural mass was detected at the T8-T9 level. The signal intensity of the mass relative to the spinal cord was isointense on T1-weighted images, hyperintense on T2-weighted images, and showed homogeneous, strong enhancement on contrast-enhanced T1-weighted images. The mass had both extramedullary and intramedullary components.     

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.     

Intradural spinal metastases in pediatric patients with primary intracranial neoplasms: Gd-DTPA enhanced MR vs CT myelography

Recently, the application of intravenous gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) has been shown to improve the detection of intradural extramedullary spinal disease in adults. The ability of Gd-DTPA enhanced magnetic resonance (MR) to detect intradural extramedullary spinal metastases was studied in pediatric brain tumor patients. Spinal MR images before and after intravenous injection of Gd-DTPA were analyzed retrospectively in eight pediatric patients with known intracranial neoplasms and clinically suspected subarachnoid tumor seedings. Contrast enhanced spinal MR was compared with CT myelography in four of these patients. In our pediatric population Gd-DTPA enhanced images revealed tumor seeding not appreciable on noncontrast images. Although CT myelography has been the accepted standard investigation in the evaluation of suspected spinal metastases in children, we found that contrast enhanced MR is equal or superior in sensitivity to CT myelography. Spinal MR also provided information not obtainable via CT myelography. In the future, Gd-DTPA enhanced spinal MR should be considered in the initial evaluation of suspected subarachnoid spinal metastases in pediatric patients with known primary brain tumors.     

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.     

Radiological findings of spinal schwannomas and meningiomas: focus on discrimination of two disease entities

This study evaluates the effectiveness of CT and MR imaging in differentiating intradural extramedullary spinal schwannomas and meningiomas in a large group of patients. In addition, the study correlates tumour location, morphologic characteristics and enhancement pattern. From January 2000 to June 2007, we retrospectively reviewed 128 consecutive patients (51 male, 77 female; mean age at admission 53.8 years; range 17–83 years) with spinal intradural extramedullary tumours (92 schwannomas, 36 meningiomas) at our institution. Fifty-one of ninety-two schwannomas (55.4%) showed fluid signal intensity on T2-weighted MR images. Twenty-two of thirty-six meningiomas (61.1%) showed hyperintense signal intensity and thirteen of thirty-six meningiomas (36.1%) showed isointense signal on T2-weighted MR images. Fifty-four schwannomas (58.7%) showed rim enhancement and thirty-three meningiomas (91.7%) showed diffuse enhancement on contrast-enhanced T1-weighted MR imaging. Twenty-one meningiomas (58.3%) showed dural tail sign in contrast-enhanced T1-weighted MR imaging. Twenty-one meningiomas (58.3%) showed calcification on CT images. MR and CT imaging results are therefore useful for the differentiation of schwannomas from meningiomas of the spine.     

Imaging of the spine and spinal cord

Recent technologic advances in MR imaging of the spine and spinal cord have been aimed at shortening examination time and suppressing artifacts. Gradient-recalled fast T2-weighted imaging is advocated for evaluating cervical radiculopathy. Better signal-to-noise ratios are achieved with three-dimensional Fourier transform gradient-recalled T2-weighted imaging and with decreased bandwidth acquisition. Obtaining high-contrast images of the spine is often complicated by the appearance of truncation artifacts. In outpatient radiculography, both iopamidol and iohexol appear safe, but iohexol seems better tolerated. In trauma, MR imaging is definitive, and signal abnormalities can help in evaluating neurologic recovery. Intraoperative spinal sonography may be helpful in evaluating acute injury. Enhancement with gadolinium diethylenetriamine penta-acetic acid is useful in the evaluation of disk space infections, osteomyelitis, and epidural abscess and in the study of spinal cord sarcoidosis. In patients with the acquired immunodeficiency syndrome, MR imaging may show hyperintense spine on T2-weighted images. MR imaging with gadolinium diethylenetriamine penta-acetic acid or gadolinium tetra-azacyclododecane tetra-acetic acid enhancement can be useful in evaluating intramedullary and intradural extramedullary tumors and for determining the extent of spinal leptomeningeal metastases. MR imaging can also be used to differentiate benign from pathologic fractures.     

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.     

Application of turbo fluid-attenuated inversion-recovery MRI in evaluation of intraspinal tumors

PURPOSE: Although fluid-attenuated inversion-recovery (FLAIR) magnetic resonance imaging (MRI) is widely applied to diagnose central nervous system diseases, its role in diagnosis of intraspinal tumors is unclear. In this study, we evaluated the potential clinical application of a turbo FLAIR sequence for imaging of intraspinal tumors. MATERIALS AND METHODS: Forty-eight consecutive patients with intraspinal tumors underwent MRI with turbo FLAIR and turbo spinal echo (TSE) sequences. Turbo FLAIR images were then qualitatively and quantitatively compared with T2-weighted TSE images. RESULTS: Turbo FLAIR images were evaluated as superior to T2-weighted TSE images for image artifact, extradural tumor conspicuity, and intradural extramedullary tumor conspicuity and detection. Intramedullary tumor conspicuity with turbo FLAIR was less than T2-weighted TSE. Similar capabilities in detection of extradural and intramedullary tumors were found between turbo FLAIR and T2-weighted TSE. Turbo FLAIR and T2-weighted TSE displayed similar normal spinal cord signal-noise ratio (SNR) and tumor-to-cerebrospinal fluid (CSF) contrast-to-noise ratio (CNR). In addition, turbo FLAIR yielded significantly higher tumor-to-CSF contrast than T2-weighted TSE. However, tumor SNR, tumor-to-normal spinal cord contrast and CNR with turbo FLAIR images were lower than those with T2-weighted TSE images. CONCLUSION: This study demonstrated (a) a superiority of turbo FLAIR to T2-weighted TSE in displaying and detecting intradural extramedullary tumors, (b) a superiority of turbo FLAIR to T2-weighted TSE in demonstrating extradural tumors, and (c) less usefulness in displaying intramedullary tumors with turbo FLAIR than with T2-weighted TSE.     

Magnetic resonance imaging spectrum of spinal meningioma

PurposeTo evaluate magnetic resonance (MR) imaging findings of spinal meningioma and to determine the radiological subtypes based on the MR imaging findings and their respective clinical features.Material and methodsData for 105 patients with surgically treated and histopathologically diagnosed spinal meningiomas at our hospital between May 1, 2003 and May 1, 2017 were evaluated in this study. Two radiologists reviewed the characteristics of spinal meningiomas on MR images and categorized the spinal meningiomas into subtypes based on MR imaging findings.ResultsMost spinal meningiomas showed higher signal intensity than that of the spinal cord but lower than that of the subcutaneous fat on T2-weighted images (WI). 56 cases (54%) showed adjacent spinal cord signal changes. Meningiomas could be categorized according to MR imaging findings into type A: dural-based tumors with a homogeneous signal intensity and intense contrast enhancement (81 cases, 77%); type B: round or oval-shaped tumors with an internal hypointense portion on T2-weighted images (18 cases, 17%); type C: en plaque tumors (three cases, 3%); and type D: tumors with unusual findings and a heterogeneous appearance (three cases, 3%). All type C patients showed spinal cord signal changes.ConclusionsSpinal meningioma showed slightly high signal intensity rather than high signal intensity on T2-weighted images. Spinal cord signal changes were present in more than half of the cases. Clinical differences were observed among the different MR imaging types.     

MR imaging of intradural inflammatory diseases of the spine

Twenty-eight patients with intradural inflammatory disease of the spine were studied in order to characterize the MR imaging findings of infectious and inflammatory conditions. Patients were categorized according to the spinal compartment involved. Among the 12 patients in the intradural extramedullary group, unenhanced scans were either normal or nonspecific while contrast-enhanced scans were helpful in visualizing and localizing the lesion. Nevertheless, contrast-enhanced MR studies were unable to differentiate infection and inflammation from tumor in this compartment. Among 16 patients with intramedullary lesions, four had granulomatous disease and 12 had nongranulomatous disease. The granulomatous lesions resembled tumors and displayed MR characteristics of a focal lesion with large nodular enhancement. The patients with nongranulomatous intramedullary lesions exhibited two subsets of MR findings. In the first subset of nine patients, diffuse cord swelling and high signal were seen on long TR images, combined with either no enhancement or peripheral, diffuse, or speckled enhancement of the spinal cord on contrast-enhanced short TR images. In the second subset of three patients, minimal or no spinal cord swelling was displayed despite the visualization of high signal on long TR scans and nodular enhancement with contrast administration on short TR scans. Both subsets were sufficiently unique that nongranulomatous myelitis could usually be differentiated from spinal cord tumors.     

Thoracic intradural arachnoid cyst: possible pitfalls with myelo-CT and MR

Summary A thoracic intradural arachnoid cyst presenting as an intradural extramedullary mass highly suggestive of psammoma on myelogram and myelo-CT is reported in a 34-year-old female. High densities of the cyst were related to collection of contrast media within the cyst. However MR examination of the thoracic spinal cord including sagittal T1 (without and with contrast) and T2 studies failed to demonstrate the mass. Lack of MR changes were related on one hand to the small size of the cyst and to the absence of mass effect on the spinal cord, and on the other hand to a CSF-like signal of the contents of the cyst. Only combination of myelography, myelo-CT and MR allows precise diagnosis of small intradural arachnoid cysts; however MR is the method of choice for evaluation of large intradural subarachnoid cysts.     

CT and MR imaging of advanced Zollinger-Ellison syndrome

The CT and magnetic resonance (MR) findings in 13 patients with advanced Zollinger-Ellison syndrome are described. In eight patients (62%) one or more primary tumors were found with both methods. All patients with proven liver metastases (n = 7) were identified by MR. Computed tomography was positive in six of these patients. Three patients with lymph node metastases were identified on CT and MR and one patient had bone metastases. Computed tomography and MR were inferior to selective arteriography in the detection of multiple lesions of the pancreas in a patient with multiple endocrine neoplasia-I syndrome. On the T1-weighted MR images, the primary tumors demonstrated no consistency with regard to their signal intensity relative to the adjacent pancreatic parenchyma. All gastrinomas had an increased relative signal intensity on the T2-weighted images with the exception of a calcified tumor. Liver and lymph node metastases had a low signal intensity on the T1-weighted images and an increased signal intensity on the T2-weighted images. The signal intensity of primary tumors and metastases was independent of size. In conclusion, MR was able to detect abnormalities based on its outstanding lesion/normal tissue contrast, whereas CT diagnosis was based mostly on contour distortion. For the current technique, MR is considered at least equal to CT.     

MR imaging of spinal lymphoma.

Fourteen patients with spinal lymphoma examined by MR imaging were reviewed. Thirteen of them also had extraspinal lymphoma. Vertebral involvement was found in 12 patients, epidural in 10, and paraspinal in 8 patients. On the basis of MR imaging at 0.3 T, spinal lymphoma may be divided into three types of growth pattern according to the main location: paraspinal, vertebral, and epidural. Most frequently, all three locations were found simultaneously on MR (7/14). In one patient the location was vertebral with epidural extension, in one paraspinal with vertebral extension, in 3 it was entirely vertebral, and in 2 entirely epidural. Multiple plane T1-weighted imaging gave complete information about the extent of spinal lymphoma. The signal intensity was lower than or equal to muscle and lower than bone marrow in paraspinal and vertebral lesions on T1-weighted images and high on T2-weighted images. Epidural lesions showed a hypo- or isointense signal relative to the cord on T1-weighted images except in one case and a hyperintense signal on T2-weighted images. Compression of the cord and cauda equina due to bulging of diseased vertebral bodies and epidural lesions was well demonstrated. MR imaging was also found useful in the follow-up of treatment.     

Importance of absence of CSF pulsation artifacts in the MR detection of significant myelographic block at 1.5 T

MR imaging was performed on 21 patients who had high-grade myelographic block due to various diseases in all spinal compartments (extradural, intradural/extramedullary, and intramedullary) and in all portions of the spinal canal (cervical, thoracic, and lumbosacral). Loss of CSF pulsation artifacts due to significant compression of the spinal cord was demonstrated on non-motion-compensated T2-weighted examinations in each case. We believe that the absence of such artifacts on these sequences indicates significant spinal cord compression in patients without classic signs and symptoms of cord compression but with intraspinal disease identified on T1-weighted studies.     

Epidural abscess of the cervical spine: MR findings in five cases.

Cervical epidural abscess is an uncommon infectious process of the spinal epidural space. Although this disorder is often unsuspected clinically, the patient's signs and symptoms may suggest other diagnoses that frequently lead to an MR examination. We retrospectively reviewed the MR examinations of five patients with surgically proved cervical epidural abscess in order to assist in the diagnosis of this clinically elusive disorder. Each epidural abscess was evaluated for MR signal intensity, location, extent, delineation, and enhancement pattern. We assessed the spinal cord for compression and signal intensity and analyzed the vertebrae, intervertebral disks, and paraspinal soft tissue. Compared with the spinal cord, the abscess was isointense or hypointense on T1-weighted spin-echo images and hyperintense on T2-weighted images. The abscess was hyperintense or isointense relative to the cord on T2* gradient-echo images. Enhancement of the abscess occurred in the two patients given an IV injection of gadopentetate dimeglumine. The epidural abscess was located anteriorly in three patients, posteriorly in one, and was circumferential in one. The abscess extended from two to nine vertebral bodies in length. In each case, the abscess caused some degree of spinal cord compression, and one patient had bright signal intensity within the cord on T2-weighted images. Three patients had MR changes of accompanying osteomyelitis and paravertebral abscess. MR imaging is useful in diagnosing cervical epidural abscess and in evaluating associated abnormality of the spinal cord, vertebral bodies, intervertebral disks, and paraspinal soft tissue.     

Gadolinium-DTPA enhanced MR imaging of spinal dural arteriovenous fistulas

To evaluate the role of magnetic resonance (MR) in the diagnosis of dural arteriovenous (AV) fistulas and the resulting myelopathy, the MR examinations of 11 patients with symptoms and signs of slowly progressive myelopathy of the lower spinal cord have been reviewed. Patients with intradural or extradural AV malformations were excluded. Six patients have been examined without the use of a contrast agent. The other five patients were studied prior and after intravenous administration of gadolinium-diethylenetriamine pentaacetic acid (DTPA). Serpentine linear areas of low signal due to flow void effects within the subdural space have been detected in seven patients. The T1-weighted sagittal images and T2-weighted sagittal and axial images demonstrated signal intensity changes within the center of the cord due to prolongation of T1 and T2 relaxation times. In addition, a relatively abrupt increase of the sagittal and transverse diameters of the lower thoracic cord was found in all cases. In nine patients T1-weighted, proton-density and T2-weighted sagittal images presented "blurred" margins of the lower thoracic cord. After intravenous administration of Gd-DTPA (0.1 mmol/kg), contrast enhancement was present not only within these vessels but also within the lower spinal cord. There was only slight enhancement of the cord immediately after injection of the contrast agent, but significant enhancement was observed 40-45 min later.     

Acute spinal cord injury: MR imaging at 1.5 T

Thirty-seven magnetic resonance (MR) imaging studies were performed with a 1.5-T magnet and surface coils in 27 patients with suspected spinal cord injuries. Imaging was performed 1 day to 6 weeks after injury. Cord abnormalities were seen with MR in 19 patients, while skeletal and/or ligamentous injuries were seen in 21 (78%). Three types of MR signal patterns were seen in association with cord injuries. Acute intraspinal hemorrhage was seen in five patients with cord injuries and demonstrated decreased signal intensity on T2-weighted images obtained within 24 hours of injury. Cord edema and contusion had high signal intensity on T2-weighted images and were observed in 12 cases with cord injury. Neurologic recovery, determined in 16 patients, was insignificant in patients with intraspinal hemorrhage; however, patients with cord edema or contusion recovered significant neurologic function. MR at 1.5 T is extremely useful in the diagnosis of acute cord injury and also demonstrates potential in predicting neurologic recovery.