MR imaging of spontaneous spinal cord infarction

Magnetic resonance imaging was utilized to evaluate three women, one of whom was pregnant, with a clinical diagnosis of anterior spinal artery syndrome. In each case, development of spinal cord infarctions was spontaneous. Sagittal and axial MR images of the spine were obtained prior to and following administration of Gd-diethylenetriamine pentaacetic acid. Magnetic resonance showed no cord enlargement or signal abnormality on T1-weighted images prior to contrast medium administration. On T2-weighted images there was abnormal increase in signal intensity in the cord at levels corresponding to the neurologic deficits in all three patients. Variable contrast enhancement was demonstrated in these areas. Magnetic resonance imaging was positive, whereas CT-myelography, carried out in the two nonpregnant women, failed to demonstrate any abnormalities.     

MRI of spinal cord and vertebral body infarction in the anterior spinal artery syndrome

We describe the temporal sequence of signal changes in the spinal cord and vertebral column following vascular damage caused by ethanol injected during surgery.     

Diffusion-weighted MR imaging of the spinal cord

Diffusion-weighted MR imaging may increase the sensitivity and specificity of MR imaging for certain pathologic conditions of the spinal cord but is rarely performed because of several technical issues. We therefore tested a novel phase-navigated spin-echo diffusion-weighted interleaved echo-planar imaging sequence in seven healthy volunteers and six patients with intramedullary lesions. We performed diffusion-weighted MR imaging of the spinal cord with high spatial resolution. Different patterns of diffusion abnormalities observed in patient studies support the possible diagnostic impact of diffusion-weighted MR imaging for diseases of the spinal cord.     

MR imaging of acute spinal cord trauma

The thoracic spinal cords of five mongrel dogs were imaged with a 1.5 T MR scanner before and after trauma induced by a well-established method of spinal cord impaction that produces central cord hemorrhagic necrosis. The anesthetized dogs were studied acutely with a 5-in. circular surface coil, 12-cm field of view, sagittal and axial partial-saturation (TR = 600, TE = 25 msec) and spin-echo (TR = 2000, TE = 25-100 msec) techniques. One normal dog was used as a control. The cords were surgically removed and histologically examined. Direct correlation of the pathologic findings and imaging data showed that at the level of trauma there was obliteration of epidural fat and CSF spaces secondary to central cord hemorrhage and edema. The traumatized cords expanded to fill the bony canal, and there was loss of visualization of the internal anatomy of the cord (gray- and white-matter structures). We conclude that MR can accurately identify cord hemorrhage and edema within a few hours of spinal trauma.     

Functional MR imaging of the human cervical spinal cord.

BACKGROUND AND PURPOSE: Although research with functional MR imaging of the brain has proliferated over the past 5 years, technical limitations, such as motion, chemical shift, and susceptibility artifacts, have impeded such research in the human spinal cord. The purpose of this investigation was to determine whether a reliable functional MR imaging signal can be elicited from the cervical spinal cord during simple motor activity. METHODS: Subjects performed three different motor tasks that activate different segments of the spinal cord. Gradient-echo-planar imaging on a 1.5-T clinical unit was used to image cervical spinal cords of human subjects. Another group of subjects was imaged while performing isometric exercise to study the relationship between the blood oxygenation level-dependent (BOLD) signal and applied force. RESULTS: Task-dependent BOLD activity was detected in all subjects. Signal amplitude varied between 0.5% and 7%. Moreover, a linear relationship was found between the applied force and the signal amplitude during isometric exercise. While regions of activation were distributed throughout the spinal cord, concentrated activity was found in the anatomic locations of expected motor innervation. CONCLUSION: The functional MR imaging signal can be reliably detected with motor activity in the human cervical spinal cord on a 1.5-T clinical unit. The location of neural activation has an anatomic correspondence to the myotome in use. The strength of the BOLD signal is directly proportional to the level of muscular activity.     

Avascular necrosis of the vertebral body: MR imaging

Five patients with plain radiographic evidence of a compressed vertebra containing an intravertebral vacuum cleft indicative of avascular necrosis underwent magnetic resonance (MR) imaging. In these patients, the T2-weighted images revealed a distinct appearance consisting of marked and discrete hyperintensity at the location of the intravertebral cleft. T1-weighted images were hypointense in this region. Recognition of this pattern is important in the MR imaging evaluation of compression fractures of the vertebral body so that confusion with malignancy or infection may be avoided, thereby obviating additional diagnostic studies.     

MR imaging of spinal cord in Devic disease

A 20-year-old man with typical features of Devic disease was studied with magnetic resonance (MR) demonstrating sequential changes of the spinal cord from swelling to atrophy. A good correlation between neurological findings and MR imaging was documented.     

扩散加权成像在脊髓梗死中的应用

目的研究扩散加权成像(DWI)在脊髓梗死中的诊断及鉴别诊断价值。方法6例临床诊断为脊髓梗死患者,在发病后1～30d内采用1.5T磁共振仪行常规MRI和DWI。DWI均采用导航回波校正多次激励平面回波序列,并在矢状面进行表观扩散系数(ADC)值的测量。结果均成功行常规MRI和DWI检查,颈髓2例,胸腰段4例。常规T2WI表现为矢状面条状和片状长T2信号(6/6),早期多伴有肿胀(5/6),轴面表现为对称长T2信号,部分呈典型“蛇眼征”。其中,1例仅累及脊髓后动脉,表现为脊髓后部长T2信号。DWI除1例接近等信号外(发病后30d),余(发病1～12d)均表现为明显高信号,ADC平均值[(0.37±0.10)×10-3mm2/s],较正常值[(0.89±0.08)×10-3mm2/s]明显减低,差异有统计学意义(t=4.71,P<0.01)。本组中2例在3个月内进行复查,DWI信号逐渐减低,同时ADC值逐渐升高至正常,分别为0.85×10-3mm2/s和0.95×10-3mm2/s。结论DWI是脊髓梗死较为特异的诊断和鉴别诊断方法,值得推广应用。     

MR imaging in the tethered spinal cord syndrome

MR examinations of the spine were reviewed in 25 patients with a clinical diagnosis of tethered spinal cord. In 21 patients (84%), the level of the tip of the conus was below the mid L2 vertebral body. The causes of the tethering were spinal lipomas (72%), tight filum terminale syndrome (12%), diastematomyelia (8%), and myelomeningocele (8%). These entities were readily identified in all instances. Bony dysraphisms were well demonstrated by MR. Interestingly, cavitary lesions/myelomalacia of the conus or the cord adjacent to the tethering lesion were seen with appropriate images in nine of 20 patients. This unexpected finding may have diagnostic and/or prognostic significance. Spinal MR was found to be extremely useful in the evaluation of the suspected tethered spinal cord. It was able to visualize the conus medullaris, assess the thickness of the filum terminale, identify traction lesions, and evaluate associated bony dysraphisms.     

Idiopathic spinal cord herniation: value of MR phase-contrast imaging.

We report two patients with an idiopathic transdural spinal cord herniation at the thoracic level. Phase-contrast MR imaging was helpful in showing an absence of CSF flow ventral to the herniated cord and a normal CSF flow pattern dorsal to the cord, which excluded a compressive posterior arachnoid cyst.     

Venous infarction of the spinal cord resulting from dural arteriovenous fistula: MR imaging findings

Three patients with spinal dural arteriovenous fistula presented with acute and/or progressive myelopathy. The thoracic cord was focally enlarged and poorly defined on MR images in two of the patients. One individual showed focal cord atrophy, and one demonstrated abnormal intrathecal vessels. In all patients MR studies revealed cord enhancement after IV administration of gadopentetate dimeglumine. The MR findings are believed to represent disruption of the blood-cord barrier associated with cord ischemia and/or infarction, which, in turn, is caused by venous stasis resulting from the fistula. The diagnosis in each case was confirmed by the combined results of myelography, spinal arteriography, and surgery. Surgical excision or embolization of the fistula produced a poor return of lost function but an arrest in the progression of paresis. One of the patients had constant severe back and leg pain postoperatively, and a follow-up MR study 5 months after surgery showed focal atrophy and persistent enhancement of the thoracic cord. The patient with preoperative focal cord atrophy had an MR examination 1 year prior to surgery, which revealed enhancement of the cord similar to that seen on the immediate preoperative MR study. This patient also had severe pain in the back and lower extremities preoperatively, which accompanied her progressive paraparesis. It is believed that long-standing enhancement of the spinal cord in patients with dural arteriovenous fistula probably results from chronic progressive venous ischemia, which may be irreversible and cause pain of a central type.     

Fixed spinal cord: diagnosis with MR imaging

Pulsatile motion of the spinal cord was examined with phase imaging techniques. Sagittal images of the spinal cord were obtained at different times of the cardiac cycle in healthy volunteers, as well as in patients in whom the spinal cord either was tethered, was compressed, or contained an intramedullary lesion. Pulsatile velocity changes of the spinal cord, observed on the phase images, were most marked at the cervical-upper thoracic level. Cord motion was found to be significantly decreased in cases in which the cord was either tethered or compressed. Cord enlargement due to an intramedullary lesion generally did not lead to decreased cord motion. Imaging of pulsatile cord motion may be clinically useful in evaluating diseases restricting cord motion or changing the status of parenchymal compliance.     

Diffusion-weighted MR imaging in acute spinal cord ischemia

We report diffusion-weighted (DW) MR findings for acute spinal cord ischemia in a 56-year-old patient. MR imaging obtained approximately 3 h after symptom onset demonstrated an area of hyperintensity on DW images, but no conspicuous signal abnormality on T2-weighted images in the conus medullaris. DW imaging of the spinal cord can contribute to the early detection of spinal cord vascular compromise.     

The lumbar vertebral body and diskovertebral junction. Radio MR imaging anatomic correlations

Radiographs and MR images of spine specimens provide superb tomographic views of changes that involve the mineralized network and the medullary content of vertebral bodies. By illustrating changes in the balance between bone resorption and formation and between fat and nonfat marrow cells, these frozen images of the reality help us to understand normal variants and lesions that develop in osseous and articular diseases of the lumbar spine.     

MR imaging of spinal cord hemangioblastoma associated with syringomyelia

A case of isolated spinal cord hemangioblastoma with associated extensive syringohydromyelia, which was evaluated by myelography, postmyelographic CT, magnetic resonance (MR), and angiography is presented. The specific preoperative and postoperative advantages of MR are given as well as a brief review of the literature.