Intramedullary High Signal Research Articles

The effects of MRI signal intensity changes and clinical manifestations on prognosis after surgical intervention for cervical spondylotic myelopathy

To investigate whether the magnetic resonance (MR) T2 image signal intensity ratio and clinical manifestations can predict the prognosis in patients with cervical spondylotic myelopathy (CSM). A total of 73 patients treated with anterior, posterior, or posterior-anterior combined surgery for compressive cervical myelopathy were enrolled retrospectively in this study. 1.5 T magnetic resonance imaging (MRI) was performed on all patients before surgery. T2-weighted images (T2WI) of sagittal signal intensity were obtained of the cervical spinal cord, and the regions of interest (ROI) were taken by 0.05 cm(2). MR T2WI of sagittal normal cord signal at the C7-T1 disc level were also obtained, and the ROI were taken by 0.3 cm(2). Signal value was measured by computer and the signal ratio between regions 0.05 cm(2) and 0.3 cm(2) calculated. Where no intramedullary high signal intensity was noted on MR T2WI, the ROI were taken by 0.05 cm(2) of the region of most severe spinal cord compression. The 73 patients were divided into three groups by hierarchical clustering analysis with signal intensity ratio (group 1: low signal intensity ratio; group 2: middle signal intensity ratio; group 3: high signal intensity ratio). Statistical analyses were performed with SPSS 11.0. There were significant differences between the three groups according to the recovery rate (P < 0.001), age (P= 0.003), duration of disease (P= 0.001), Babinski sign (P < 0.001), pre- and postoperative Japanese Orthopaedic Association (JOA) score (P= 0.006). With increases in both signal intensity ratio grade and age, the recovery rate and pre- and postoperative JOA scores gradually decreased, and the incidence of Babinski sign increased. There was no significant difference in sex among the three groups (P= 0.387). Multiple comparison tests further supported the above-mentioned results. Patients with light or no intramedullary signal changes on T2WI had a good surgical outcome. However, increase of signal intensity ratio and occurrence of the pyramidal sign were associated with a poor prognosis after surgery.

Experience of Epidural Steroids in Transverse Myelitis -A case report-

Transverse myelitis is a focal inflammatory disorder of the spinal cord characterized by motor, sensory, and autonomic dysfunction. A 41-year-old man with transverse myelitis and no pre-existing neurologic disease presented with hypesthesia, numbness, weakness in the both lower extremities, back pain, decreased libido, constipation, and dysuria. A MRI test showed intramedullary high signal intensity between T4 and T8 on a T2-weighted image. After high-dose intravenous methylprednisolone and oral prednisolone therapy, he showed facial swelling and acneiform eruption. Therefore, we injected 40 mg methylprednisolone via an epidural route. A 7-dose serial treatment improved most symptoms. A follow up MRI showed radiological improvement. We report a case of transverse myelitis treated by epidural steroids.

Relation of MR T2 image signal intensity ratio of cervical spondylotic myelopathy with clinical manifestations and prognosis

To investigate whether the signal intensity ratio in magnetic resonance imaging (MRI) and clinical manifestations can reflect prognosis in patients with cervical compressive myelopathy. Seventy-three patients with cervical compressive myelopathy treated with anterior, posterior, or posterior-anterior united decompression underwent 1.5-T MRI before surgery. T2-weighted images (T2WI) of the sagittal signal intensity on the cervical severe compression cord were obtained, and the regions of interest (ROIs) were taken by 0.05 cm(2). T2-weighted MR images of sagittal normal cord signal on the cervical between C7-T1 disc levels were obtained, and the ROIs were taken by 0.3 cm(2). Signal value is measured by computer and the signal ratio between the regions of the 0.05 cm(2) and 0.3 cm(2) was calculated. If no intramedullary high signal intensity was noted on T2-weighted MR images, the ROIs were taken by 0.05 cm(2) of the severe compression cord. The 73 patients were divided into 3 groups: low, medium, and high signal ratio groups (Group 1, 2, and 3, n = 18, 32, and 23 respectively). The recovery rate and JOA score of Group 1 were significantly higher, the age and Babinski sign positive rate were significantly lower, and disease duration was shorter in Group 1 than in Groups 2 and 3 (F = 22.009, P < 0.001, F = 5.561, P = 0.006, F = 6.371, P = 0.003, chi(2) = 15.719, P < 0.001, and chi(2) = 13.952, P = 0.001). There was no significant differences in sex among these 3 groups (chi(2) = 1.898, P = 0.387). The patients with light or without intramedullary signal change on T2WI experience a good surgical outcome. However, the patients with increase of signal intensity ratio and the occurrence of pyramidal sign show a poor prognosis after surgery.

Clinical and MRI Predictors of Outcome After Surgical Intervention for Cervical Spondylotic Myelopathy

Cervical spondylotic myelopathy (CSM) is the most common cause of spinal cord dysfunction in older individuals. Controversy remains in terms of the optimal timing and indications for surgical intervention. In this context, it would be of benefit to define clinical and magnetic resonance imaging (MRI) predictors of outcome after intervention for CSM. We studied subjects with clinically documented cervical myelopathy to evaluate the relationship among preoperative MRI signal change, clinical findings, and outcome after surgical intervention. We performed a retrospective case study of 76 CSM patients who underwent cervical decompressive surgery and who had pre- and postoperative MRI studies available for review. Preoperative clinical findings and MRI abnormalities on T1- (T1WI) and T2-weighted (T2WI) images were correlated with outcomes (Nurick scores; Odom's criteria) following surgical intervention. Postoperative MRIs were performed 2-4 months postsurgery to assess for adequacy of decompression and resolution of preoperative signal changes. The pattern of spinal cord signal intensity was classified as: Group A (MRI N/N), no intramedullary signal intensity abnormality on T1WI or T2WI; Group B (MRI N/Hi), no intramedullary signal intensity abnormality on T1WI and high intramedullary signal intensity on T2WI; Group C (MRI Lo/Hi), low intensity intramedullary signal abnormality on T1WI and high intensity intramedullary signal abnormality on T2WI. Statistical analyses were performed using SAS (version 8.2). We evaluated 76 patients (57% males, mean age 62 years, range 30-89) who experienced preoperative symptoms for an average of 6.5 months (range 1 month to 9 years). Preoperative MRI studies demonstrated the following: Group A (MRI N/N) = 45; Group B (MRI N/Hi) = 23; and Group C (MRI Lo/Hi) = 8. The mean postoperative follow-up period was 2.5 years (range 2 months to 8.5 years). A positive Babinski sign and the presence of intrinsic hand muscle atrophy showed the greatest association with abnormal preoperative MRI signal change. High preoperative Nurick score, clonus, and leg spasticity were associated with a less favorable postoperative outcome. In Group B (MRI N/Hi), 11/23 (52.17%) patients had recovery to MRI N/N (P < .0001) at their follow-up scan. Patients with high intramedullary signal change on T2WI who do not have clonus or spasticity may experience a good surgical outcome and may have reversal of the MRI abnormality. A less favorable surgical outcome is predicted by the presence of low intramedullary signal on T1WI, clonus, or spasticity. These data suggest that there may be a window of opportunity to obtain optimal surgical outcomes in patients with CSM.

Spinal Cord Compression Related to Cervical Disc Herniation in Different Age Groups

Our purpose was to determine the levels of cervical disc herniations and their relationship with intramedullary high signal intensity in magnetic resonance images of patients with clinical diagnosis of disc herniation. Four hundred forty-five patients with the clinical diagnosis of disc herniation were included. Disc herniations were mostly detected in 40 to 49 and 50 to 59 age groups. The most commonly involved intervertebral disc level was C5-C6. The patients with 4 levels disc herniations were mostly seen in 50 to 59 age group. Disc compression was observed in 90 patients and mostly seen in 50 to 59 age group. Intramedullary high signal intensity was detected in 22 patients and they were all type 1. In conclusion, pathologies related to disc degeneration can be observed in patients with neck pain as age increases even without any neurologic deficits. Therefore, a detailed analysis of all data for each patient is crucial in making the decision of any surgical intervention.

Cervical Myelopathy Secondary to Atlas Hypoplasia - Reports of 3 Adult Cases -

There have been paucity of reports on atlas hypoplasia, and as a result this condition is not clearly defined, nor well understood. The authors reported three cases of atlas hypoplasia that were found in adults who presented with myelopathic symptoms. On radiographic examination, it was found that the anterior-posterior diameter of the atlas was remarkably narrower in all three cases in comparison with normal persons. The MRI in all three cases also revealed intramedullary high signal lesions at the levels where severe spinal cord compression was present. This led to our diagnosis of atlas hypoplasia causing myelopathy.

A review of factors predictive of surgical outcome for ossification of the ligamentum flavum of the thoracic spine

Ossification of the ligamentum flavum (OLF) is a pathological condition that affects the ligament and causes slowly progressive myeloradiculopathy in adults. Although OLF has been regarded as endemic to East Asian countries, studies from outside these areas have increasingly been reported. Because of long-standing compression of the spinal cord by OLF, a patient's functional prognosis may not always be favorable, and attempts have been made in recent studies to identify clinical factors that are predictive of the surgical outcome of patients with thoracic OLF. The authors conducted a review of the literature published in the English, Japanese, and Korean languages. They examined studies in which correlation between clinical factors and outcome was statistically evaluated. The clinical factors included sex, age, level of the ossified ligamentum flavum, number of segments affected by OLF, coexisting ossification of the posterior longitudinal ligament (OPLL) or other spinal disorders, preoperative duration of symptoms, preoperative neurological score, computed tomography (CT)-based classification, and the presence of intramedullary high signal intensity on T2-weighted magnetic resonance images. The clinical factors that are unlikely to be predictive of outcome include sex, age, level of the ossified lesion, number of OLF-affected segments, coexisting OPLL, CT classification, and the presence of high signal intensity. It is unclear whether the preoperative duration of symptoms or neurological score is predictive of outcome because the results have been inconsistent among the studies. Analysis of the more recent literature, however, suggests that these two factors are predictive of outcome. The use of a neurological score should be standardized so that compilation and comparison of data can be facilitated.

Clinical and prognostic analysis of ossified ligamentum flavum in a Chinese population

The authors performed a retrospective study of clinical and radiological data obtained in 27 Chinese patients with myelopathy induced by ossification of the ligamentum flavum (OLF) who underwent surgery between March 1990 and March 2002. The factors related to surgical outcome of thoracic OLF-induced myelopathy were also assessed. The preoperative clinical features and radiological findings were reviewed retrospectively. Preoperative and postoperative neurological status was assessed using the Japanese Orthopaedic Association (JOA) scoring system and the Nurick Scale. The ossified lesions were classified into five types (lateral, extended, enlarged, fused, and tuberous). Multiple linear regression and logistic regression analyses were performed to establish the factors affecting surgical outcome. The patients' chief complaints were lower-limb weakness and gait disturbance (93%), numbness and sensory deficit (89%), and low-back pain (48%). The coexisting pathological entities were disc herniation, canal stenosis, and ossification of posterior longitudinal ligament. The ossified ligamentum flavum was mainly located at the T10-12 (67%) and T1-3 (15%) levels. Symptoms in 26 patients improved but resolved completely in only 14 after surgery. The mean overall JOA score was 5.3 +/- 1.9 preoperatively and 7.9 +/- 2.3 postoperatively. There is a significant difference between the pre- and postoperative neurological status (p < 0.05) determined by the Student t-test. The recovery rate was 46.3 +/- 9.4%. Multiple regression analysis revealed negative correlation between the duration of preoperative symptoms and surgical outcome as well as a positive correlation between the preoperative JOA score and surgical outcome. Logistic regression analysis demonstrated that fecal and/or urinary incontinence, positive patellar and/or ankle clonus, and intramedullary high T2-weighted magnetic resonance (MR) imaging signal change had negative effects on the surgical outcome. The clinical and radiological features of OLF in the Chinese population are similar to those observed in the Japanese population. The duration of preoperative symptoms and JOA score are the most important predictors of the postoperative JOA score and recovery rate. The patients with fecal and/or urinary incontinence, positive patellar and/or ankle clonus, and intramedullary high T2-weighted MR imaging signal change were at higher risk of poor outcome after surgery.

The motor conduction of cervical spondylotic myelopathy with intramedullary high signal intensity on MRI

We investigated an influence of the T2 weighted MR imaging (MRI)-documented intramedullary high signal intensity (IMHSI) on the motor conduction in cervical spondylotic myelopathy (CSM) patients. We measured the central motor conduction time (CMCT) and the latency from anterior horn cell to rootlet (CRL) of Biceps Brachii (biceps), Triceps Brachii (triceps) and Abductor Policis Brevi (APB) of 58 hands of 29 patients. The severity of myelopathy was evaluated by Japan Orthopaedic Association Scoring system (JOA score). CMCT of APB demonstrated good relationship ( r=0.71, p=0.0001) with JOA score whereas no relationship existed in measurement of the CMCT of the biceps nor the triceps. And only the CMCT of the APB of the patients with IMHSI were significantly longer (Mann Whitney- U-test, p<0.05) than that of the patients without IMHSI. CRL had no relationship with the localized site of the high intensity area. The motor conduction time measurement could not diagnosis the localized site of IMHSI. The motor fiber of APB was more vulnerable than that of the biceps and the triceps in the spinal cord with IMHSI.

Mielopatía cervical: análisis retrospectivo de los resultados quirúrgicos de 54 pacientes tratados mediante discectomía y fusión intersomática por vía anterior

Patients and methodsWe perform a retrospective analysis of clinical results in 53 consecutive patients surgically treated for cervical myelopathy or myelo-radiculopathy with anterior cervical discectomy and interbody fusión by means of the Cloward procedure. Results64.2% of the patients had good outcome as measured by the improvement in one or more grades in the Nurick's scale. No mortality related to the surgical procedure was noted, although 9.4% of the cases suffered neurological deterioration. Correct fusión was achieved in 92.5% of the patients, with a rate of post-surgical kyphosis of 9.4%. Multivariate analysis identified as factors related to the clinical outcome: age (p=0.008), vascular risk factors (p=0.031), duration of symptoms (p=0.002), pre-surgical neurological status (p<0.001), neuroradiological diagnosis (p=0.014), intramedullary high signal intensity changes in T2-weighted images (p=0.008), prolongation of the central somatosensory or motor conduction times (p=0.004) and neurologic complications (p=0.012) ConclusionsTreatment optimisation of the patient suffering cervical spondylotic myelopathy requires individualised evaluation. Prospective randomised studies are needed to answer the questions when and how to opérate.

The use of evoked potentials for clinical correlation and surgical outcome in cervical spondylotic myelopathy with intramedullary high signal intensity on MRI

Objective: To investigate the use of motor evoked potentials (MEPs) and somatosensory evoked potentials (SEPs) for clinical significance and surgical outcome in patients with cervical spondylotic myelopathy (CSM) with intramedullary...

Clinicopathological study of "snake-eye appearance" in compressive myelopathy of the cervical spinal cord.

The goal of this study was to elucidate the pathophysiological features and clinical significance of the magnetic resonance imaging-documented small intramedullary high signal intensity known as "snake-eye appearance" (SEA) in cases of compressive myelopathy such as cervical spondylosis or ossification of the posterior longitudinal ligament. One hundred forty-four patients with compression myelopathy who underwent surgery between 1998 and 2000 were selected. Intramedullary high signal intensity was found in 79 cases and was divided into two types, SEA and non-SEA (NSEA). The Japan Orthopaedic Association (JOA) scoring system was used for evaluation of pre- and postoperative neurological status. In nine cases of SEA autopsy was performed and specimens were histologically analyzed. The improvement ratio determined by JOA score was 32.2 +/- 15.1% in SEA, 47.1 +/- 12.1% in NSEA, and 50 +/- 18.3% (p < 0.01) in control cases in which high signal intesity was absent. There were significant differences among SEA, NSEA, and control groups. In a separate group of nine patients who died of unrelated causes, histological examination showed small cystic necrosis in the center of the central gray matter of the ventrolateral posterior column and significant neuronal loss in the flattened anterior horn. Snake-eye appearance was found to be a product of cystic necrosis resulting from mechanical compression and venous infarction. Destruction of the gray matter accompanying significant neuronal loss in the anterior horn suggested that SEA is an unfavorable prognostic factor for the recovery of upper-extremity motor weakness.

Cervical degenerative disease at flexion-extension MR imaging: prediction criteria.

To determine if there are any neutral-position imaging criteria that can help predict functional cord impingement at flexion-extension cervical magnetic resonance (MR) imaging. Sixty-two patients with cervical degenerative disease were evaluated with regard to the dynamic changes of canal stenosis at flexion-extension MR imaging. Functional cord impingement was considered if the cord was impinged or more impinged after neck flexion or extension. Selection criteria for neutral-position MR imaging, such as cervical curvature, canal space, degenerative stage, intramedullary high signal intensity on T2-weighted images, and resting instability, were evaluated for their ability to predict functional cord impingement at flexion-extension MR imaging (Fisher exact test, logistic regression analysis). MR images in 19 (31%) of 62 patients showed functional cord impingement at extension MR imaging compared with images in two (3%) patients at flexion MR imaging. Statistically significant differences were found for the criteria cervical degeneration stage (P <.001) and spinal canal space (P =.037) for predicting functional cord impingement at extension MR imaging. In contrast, no significant differences were found among selection criteria for flexion MR imaging. Probabilities of functional cord impingement at extension MR imaging were calculated with different combinations of degenerative stages and canal spaces. Probability could increase to 79% if the patient had both stabilization degeneration (disk protrusion or osteophytic formation with hypertrophy of the ligamentum flavum) and C7 canal space of 10 mm or less. None of the selection criteria evaluated in this study has the ability to predict functional cord impingement at flexion MR imaging; however, prediction of impingement at extension MR imaging can increase from 31% to 79% if proper criteria are selected.

Intramedullary high signal intensity on T2-weighted MR images in cervical spondylotic myelopathy: prediction of prognosis with type of intensity.

To examine whether the different appearances of intramedullary high signal intensity (SI) on T2-weighted MR images in cervical spondylotic myelopathy are related to differences in surgical prognosis. The magnetic resonance (MR) findings and Japanese Orthopedic Association (JOA) score of 64 cervical spondylotic myelopathy patients, who underwent decompression surgery, were evaluated. SIs were classified as type 0 if no intramedullary high SI on T2-weighted MR images was noted, type 1 if a predominantly (>50%) faint and fuzzy border of high SI was noted, or type 2 if a predominantly (>50%) intense and well-defined border of high SI was noted. Postoperative JOA scoring and MR imaging were also performed 6 months after surgery. Recovery ratios were calculated. There were 20 type 0, 23 type 1, and 21 type 2 cases. Statistical analyses showed no significant difference in age, sex, cervical curvature, and preoperative JOA score between the three groups. Statistical analyses of the recovery ratio showed significantly poor prognosis of type 2 compared with type 1 (P < .001) and type 0 (P =.001), but no difference between types 0 and 1 (P = .317). After controlling for factors of age, sex, preoperative JOA score, cervical curvature, and cord compression ratio, analysis of covariance showed the same result. Type 1 intramedullary high SI on T2-weighted MR images indicates a better surgical outcome than does type 2.

A new rabbit model for the study on cervical compressive myelopathy

Development process and pathology of myelopathy due to chronic spinal cord compression have not been fully elucidated. This study was conducted in order to establish an experimental model which can efficiently produce myelopathy and be useful in the studies on myelopathy due to chronic spinal cord compression. Under electrophysiological monitoring of the spinal cord, anterior compression was produced on C5 using a plastic screw. Two weeks later, a plastic plate was inserted under the C5 arch. For the subsequent 10 months on average, walking pattern and MR images were periodically monitored. Before the sacrifice, electrophysiological test was performed and then histopathological examination was done. Palsy appeared at 5 months on average after the addition of posterior compression. Mean compression ratio of the spinal cord calculated on MR images was 34%. All animals with compression showed a high intramedullary signal intensity, and the mean contrast-to-noise ratio (CNR) in the compressed area was 49%. Electrophysiological test showed a significant decrease in the amplitude of spinal cord evoked potentials (SCEPs) at the given compression level. Histology showed flattening of the anterior horn, disappearance and necrosis of anterior horn cells in the gray matter; and demyelination and axonal degeneration in the white matter. The antero-posterior compression produces the condition of spinal canal stenosis. Repeated antero-posterior compression to the spinal cord is important in establishing myelopathy. The present animal model was evaluated to be useful in the studies on myelopathy.

Spinal Dural AVF Two Cases with MRI Follow-up

Spinal dural arteriovenous fistula (d-AVF) is one of the arteriovenous malformations that are treatable by surgery or embolization. We present two cases treated by embolization and stress the necessity of early diagnosis and treatment, and the usefulness of T2WI on MRI for follow-up after embolization. One was a 51-year-old man who presented with gait disturbance and sphincter dysfunction. MRI revealed diffuse swelling on T1WI, and intramedullary high signal intensity on T2WI. A spinal d-AVF was found through tiny radicullomeningeal arteries via the right Th12 intercostal artery that drained into engorged retromedullary veins. The spinal d-AVF was embolized with 50% NBCA. Six months after the embolization, he was able to go back to his job, T2WI showed disappearance of the high signal intensity, which was confirmed at angiography one year after the embolization. The other case was a 62-year-old man who presented with sensory disturbance and gait disturbance. MRI showed the same findings, without the flow voids on them in case 1. The high signal area in the central spinal cord was thought to be syringomyelia, in which a syrinx-subarachnoid shunt was tried in vain. On the surface of the spinal cord, abnormally engorged and tortuous vessels were found. The syrinx was not confirmed. An angiogram showed a spinal d-AVF fed by the radicullomeningeal artery through a common trunk of the Th11/12 intercostal arteries with drainage into the retromedullary vein. The spinal d-AVF was embolized. Six months after the embolization, T2WI showed a decrease of high intensity areas. Early diagnosis and treatment are important for the prognosis of spinal d-AVF. T2WI may be the best way to check for recurrence.