Metabolic neuroimaging of the cervical spinal cord in patients with compressive myelopathy: a high-resolution positron emission tomography study

Physiological fluorodeoxyglucose uptake of spinal cord in adults

OBJECTIVE

Physiological fluorodeoxyglucose (FDG) uptake of spinal cord needs to be correctly recognized during evaluation of whole-body PET scans, especially for oncological cases. Our aim was to analyze physiological cord FDG uptake and its relation to gender, age, body weight, environmental temperature and time to imaging.

MATERIALS AND METHODS

PET scans of 254 patients in a single year, one patient for every working day were retrospectively selected. Temperature data were obtained from meteorology recordings. Maximum standard uptake value (SUVmax) of spinal cord at cervical and lower thoracic levels were noted. Spinal canal at L5 level, cerebellum and liver were used for normalization. Correlations with age, body weight, time to imaging and environmental temperature were analyzed.

RESULTS

Cervical SUV was higher than thoracic SUV (2.5-2.3). Cervical and lower thoracic SUV's were strongly correlated, highest when corrected with L5 level vertebral canal and liver (corr coeff 0.84 and 0.75) and lowest with cerebellum (corr coeff 0.4). Cervical spinal cord FDG uptake was higher for females than males (2.6 to 2.4). Temperature and age did not change spinal cord uptake. There were weak positive correlations with body weight (corr coeff 0.16 and 0.28, cervical and thoracic). There was weak negative correlation of cervical uptake with time to imaging (corr coeff -0.17).

CONCLUSION

Spinal cord FDG uptake at cervical and lower thoracic levels are strongly correlated. Females have slightly higher cervical SUV. Age and temperature does not change spinal cord FDG uptake in adults. Cord SUV's slightly increased with body weight.

Detection of nociceptive-related metabolic activity in the spinal cord of low back pain patients using 18F-FDG PET/CT

Background

Over the past couple of decades, a number of centers in the brain have been identified as important sites of nociceptive processing and are collectively known as the ‘pain matrix.’ Imaging tools such as functional magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) have played roles in defining these pain-relevant, physiologically active brain regions. Similarly, certain segments of the spinal cord are likely more metabolically active in the setting of pain conditions, the location of which is dependent upon location of symptoms. However, little is known about the physiologic changes in the spinal cord in the context of pain. This study aimed to determine whether uptake of 18F-FDG in the spinal cord on positron emission tomography/computed tomography (PET/CT) of patients with low back pain (LBP) differs from that of patients without LBP.

Methods

We conducted a retrospective review of 18F-FDG PET/CT scans of 26 patients with non-central nervous system cancers, 13 of whom had reported LBP and 13 of whom were free of LBP (controls). No patients had spinal stenosis or significant 18F-FDG contribution of degenerative changes of the spine into the spinal canal. Circular regions of interests were drawn within the spinal canal on transaxial images, excluding bony or discal elements of the spine, and the maximum standardized uptake value (SUVmax) of every slice from spinal nerves C1 to S1 was obtained. SUVmax were normalized by subtracting the SUVmax of spinal nerve L5, as minimal neural tissue is present at this level. Normalized SUVmax of LBP patients were compared to those of LBP-free patients at each vertebral level.

Results

We found the normalized SUVmax of patients with LBP to be significantly greater than those of control patients when jointly tested at spinal nerves of T7, T8, T9 and T10 (p < 0.001). No significant difference was found between the two groups at other levels of the spinal cord. Within the two groups, normalized SUVmax generally decreased cephalocaudally.

Conclusions

Patients with LBP show increased uptake of 18F-FDG in the caudal aspect of the thoracic spinal cord, compared to patients without LBP.

Implications

This paper demonstrates the potential of 18F-FDG PET/CT as a biomarker of increased metabolic activity in the spinal cord related to LBP. As such, it could potentially aid in the treatment of LBP by localizing physiologically active spinal cord regions and guiding minimally invasive delivery of analgesics or stimulators to relevant levels of the spinal cord.

Mechanical and cellular processes driving cervical myelopathy

Cervical myelopathy is a well-described clinical syndrome that may evolve from a combination of etiological mechanisms. It is traditionally classified by cervical spinal cord and/or nerve root compression which varies in severity and number of levels involved. The vast array of clinical manifestations of cervical myelopathy cannot fully be explained by the simple concept that a narrowed spinal canal causes compression of the cord, local tissue ischemia, injury and neurological impairment. Despite advances in surgical technology and treatment innovations, there are limited neuro-protective treatments for cervical myelopathy, which reflects an incomplete understanding of the pathophysiological processes involved in this disease. The aim of this review is to provide a comprehensive overview of the key pathophysiological processes at play in the development of cervical myelopathy.

FDG-PET imaging in mild traumatic brain injury: a critical review

Traumatic brain injury (TBI) affects an estimated 1.7 million people in the United States and is a contributing factor to one third of all injury related deaths annually. According to the CDC, approximately 75% of all reported TBIs are concussions or considered mild in form, although the number of unreported mild TBIs (mTBI) and patients not seeking medical attention is unknown. Currently, classification of mTBI or concussion is a clinical assessment since diagnostic imaging is typically inconclusive due to subtle, obscure, or absent changes in anatomical or physiological parameters measured using standard magnetic resonance (MR) or computed tomography (CT) imaging protocols. Molecular imaging techniques that examine functional processes within the brain, such as measurement of glucose uptake and metabolism using [¹⁸F]fluorodeoxyglucose and positron emission tomography (FDG-PET), have the ability to detect changes after mTBI. Recent technological improvements in the resolution of PET systems, the integration of PET with magnetic resonance imaging (MRI), and the availability of normal healthy human databases and commercial image analysis software contribute to the growing use of molecular imaging in basic science research and advances in clinical imaging. This review will discuss the technological considerations and limitations of FDG-PET, including differentiation between glucose uptake and glucose metabolism and the significance of these measurements. In addition, the current state of FDG-PET imaging in assessing mTBI in clinical and preclinical research will be considered. Finally, this review will provide insight into potential critical data elements and recommended standardization to improve the application of FDG-PET to mTBI research and clinical practice.

Clinical value of 2-deoxy-[18F]fluoro-d-glucose positron emission tomography in patients with cervical spondylotic myelopathy

Cervical spondylotic myelopathy (CSM) is one of the most common spinal cord disorders in the elderly. It is usually diagnosed by MRI, but in a significant number of patients the clinical course of CSM does not correlate with the extent of the spinal cord compression. Recent studies have suggested that a distinct metabolic pattern of the cervical cord, as assessed by PET with 2-deoxy-[18F]fluoro-d-glucose (18F-FDG) may predict a patient's clinical outcome after decompressive surgery for cervical spine stenosis. The authors provide an overview of the recent literature regarding the value of PET with 18F-FDG of the cervical cord in patients with CSM, paying attention to prognostic aspects and the potential role of inflammatory processes in the acute phase of the disease.

The current state-of-the-art of spinal cord imaging: methods

A first-ever spinal cord imaging meeting was sponsored by the International Spinal Research Trust and the Wings for Life Foundation with the aim of identifying the current state-of-the-art of spinal cord imaging, the current greatest challenges, and greatest needs for future development. This meeting was attended by a small group of invited experts spanning all aspects of spinal cord imaging from basic research to clinical practice. The greatest current challenges for spinal cord imaging were identified as arising from the imaging environment itself; difficult imaging environment created by the bone surrounding the spinal canal, physiological motion of the cord and adjacent tissues, and small cross-sectional dimensions of the spinal cord, exacerbated by metallic implants often present in injured patients. Challenges were also identified as a result of a lack of "critical mass" of researchers taking on the development of spinal cord imaging, affecting both the rate of progress in the field, and the demand for equipment and software to manufacturers to produce the necessary tools. Here we define the current state-of-the-art of spinal cord imaging, discuss the underlying theory and challenges, and present the evidence for the current and potential power of these methods. In two review papers (part I and part II), we propose that the challenges can be overcome with advances in methods, improving availability and effectiveness of methods, and linking existing researchers to create the necessary scientific and clinical network to advance the rate of progress and impact of the research.

Clinical significance of MRI/(18)F-FDG PET fusion imaging of the spinal cord in patients with cervical compressive myelopathy

PURPOSE

(18)F-FDG PET is used to investigate the metabolic activity of neural tissue. MRI is used to visualize morphological changes, but the relationship between intramedullary signal changes and clinical outcome remains controversial. The present study was designed to evaluate the use of 3-D MRI/(18)F-FDG PET fusion imaging for defining intramedullary signal changes on MRI scans and local glucose metabolic rate measured on (18)F-FDG PET scans in relation to clinical outcome and prognosis.

METHODS

We studied 24 patients undergoing decompressive surgery for cervical compressive myelopathy. All patients underwent 3-D MRI and (18)F-FDG PET before surgery. Quantitative analysis of intramedullary signal changes on MRI scans included calculation of the signal intensity ratio (SIR) as the ratio between the increased lesional signal intensity and the signal intensity at the level of the C7/T1 disc. Using an Advantage workstation, the same slices of cervical 3-D MRI and (18)F-FDG PET images were fused. On the fused images, the maximal count of the lesion was adopted as the standardized uptake value (SUV(max)). In a similar manner to SIR, the SUV ratio (SUVR) was also calculated. Neurological assessment was conducted using the Japanese Orthopedic Association (JOA) scoring system for cervical myelopathy.

RESULTS

The SIR on T1-weighted (T1-W) images, but not SIR on T2-W images, was significantly correlated with preoperative JOA score and postoperative neurological improvement. Lesion SUV(max) was significantly correlated with SIR on T1-W images, but not with SIR on T2-W images, and also with postoperative neurological outcome. The SUVR correlated better than SIR on T1-W images and lesion SUV(max) with neurological improvement. Longer symptom duration was correlated negatively with SIR on T1-W images, positively with SIR on T2-W images, and negatively with SUV(max).

CONCLUSION

Our results suggest that low-intensity signal on T1-W images, but not on T2-W images, is correlated with a poor postoperative neurological outcome. SUV(max) of lesions showing increased signal intensity and SUVR measured on fusion MRI/PET scans are more sensitive parameters for predicting clinical outcome than signal intensity on the MRI scan.

Pattern of 18F-FDG uptake in the spinal cord in patients with non-central nervous system malignancy

STUDY DESIGN

Retrospective review.

OBJECTIVE

To (1) propose a standard method to quantitate 2-deoxy-2-[18F]-fluoro-D-glucose (18F-FDG) uptake in the spinal cord and (2) use this methodology to retrospectively characterize the pattern of uptake within the entire spinal cord using whole-body positron emission tomography/computed tomography (PET/CT) imaging.

SUMMARY OF BACKGROUND DATA

A physiologic understanding of glucose metabolism within the spinal cord may provide insight regarding infectious, inflammatory, vascular, and neoplastic spinal cord diseases.

METHODS

Institutional review board approval was obtained. A total of 131 consecutive whole-body PET/CT studies from July to August 2004 were reviewed, and using exclusionary criteria of: (1) severe spinal arthropathy or curvature, (2) motion artifact, (3) canal hardware, (4) spinal tumor, and (5) marrow hyperplasia, 92 studies of neurologically intact patients (49 men and 43 women) were selected for a retrospective review of spinal cord 18F-FDG activity. The transaxial CT was used to define the canal and circular regions of interests were placed within the canal at the level of the vertebral body midpoint from C1 to L3. Region of interest total count, area, and maximum standardized uptake value (SUVmax) were recorded. Measurements at L5 served as an internal control. For comparative analysis, the cord-to-background (CTB) ratio was defined as spinal cord SUVmax to L5 SUVmax.

RESULTS

Mean CTB decreased along each spinal level from cranial to caudal (P < 0.001). Significant relative increases were observed at the T11-T12 vertebral body levels (P < 0.001). Although insignificant, a relative increase was observed at C4. No significant interactions of age or sex on CTB were observed.

CONCLUSION

The pattern of 18F-FDG uptake within the spinal cord, observed in patients with non-central nervous system malignancy, may be helpful in understanding glucose physiology of spinal cord diseases and warrants further research.

Imaging modalities for cervical spondylotic stenosis and myelopathy

Cervical spondylosis is a spectrum of pathology presenting as neck pain, radiculopathy, and myelopathy or all in combination. Diagnostic imaging is essential to diagnosis and preoperative planning. We discuss the modalities of imaging in common practice. We examine the use of imaging to differentiate among central, subarticular, and lateral stenosis and in the assessment of myelopathy.

Epidural abscess associated with pyogenic spondylodiscitis of the lumbar spine; evaluation of a new MRI staging classification and imaging findings as indicators of surgical management: a retrospective study of 37 patients

INTRODUCTION

The aim of this study was to review the patients with lumbar epidural abscess in terms of neurological morbidity, therapeutic outcome, and prognosis, while assessing the usefulness of a new MRI staging classification and specific imaging findings as indicators for surgical management.

MATERIALS AND METHODS

We reviewed 37 patients who sustained epidural abscess associated with pyogenic spondylodiscitis of the lumbar spine. Ten patients were treated conservatively, while 27 required urgent or elective surgical drainage. We studied patients with respect to symptomatology, Frankel-American Spinal Injury Association (ASIA) scale evaluation and a new proposed system of MRI staging of pyogenic spondylodiscitis (stages I–V).

RESULTS

Of the 37 patients with stage IV and V MRI lesions, 13 (35%) had septicemia and 8 (22%) presented with Frankel-ASIA scale C-D neurological status. All cases with ringlike enhancement on gadolinium-enhanced MRI in the epidural abscess lesions were treated surgically. Progression of local kyphosis and loss of intervertebral disk height were significantly prevented in the surgical group (P < 0.05). Improvements of neurological status and laboratory data were better in the surgical group than the conservative group (P < 0.05), with significantly short hospital stay (P < 0.05).

DISCUSSION

Epidural abscess associated with pyogenic spondylodiscitis presents with various neurological symptoms. In addition to assessment of progression by clinical symptomatology, modified neurological Frankel-ASIA scaling and the currently proposed MRI staging regimen may help to consider the timing of surgical intervention. In the acute, subacute or acute-on-chronic phase and the ringlike enhancement pattern of epidural abscess on gadolinium-enhanced MRI may be an indicator for surgery.

Cervical spondylotic myelopathy associated with kyphosis or sagittal sigmoid alignment: outcome after anterior or posterior decompression

Object

The effects of sagittal kyphotic deformities or mechanical stress on the development of cervical spondylotic myelopathy, or the reduction and fusion of kyphotic sagittal alignment have not been consistently documented. The aim in this study was to determine the effects of kyphotic sagittal alignment of the cervical spine in terms of neurological morbidity and outcome after 2 types of surgical intervention.

Methods

The authors retrospectively reviewed the records of 476 patients who underwent cervical spine surgeries for spondylotic myelopathy between 1993 and 2006 at their university medical center. Among these were identified 43 patients—30 men and 13 women, with a mean age of 58.8 years—who had cervical kyphosis exceeding 10° on preoperative sagittal lateral radiographs obtained in the neutral position, and their cases were analyzed in this study. Anterior decompression with interbody fusion was conducted in 28 patients, and en bloc open-door C3–7 laminoplasty in 15 patients. Both pre- and postoperative neurological, radiographic, and MR imaging findings were assessed in both surgical groups.

Results

The mean preoperative kyphotic angle in all 43 patients was 15.9 ± 5.9° in the neutral position. Segmental instability was noted in 26 patients (61%) and reversed dynamic spinal canal stenosis at the level above the local kyphosis in 22 (51%). Preoperative T2-weighted MR images showed high-intensity signal within the cord at and around the level of maximal compression or segmental instability in 28 patients (65%). The mean kyphotic angle in both the neutral and flexion positions was significantly smaller at 4–6 weeks after surgery in the anterior spondylectomy group than in the laminoplasty group (p < 0.001). Furthermore, the angle in the neutral position was significantly smaller on follow-up in the anterior spondylectomy group than in the laminoplasty group (p = 0.034). The transverse area of the spinal cord was significantly larger in the anterior spondylectomy group than in the laminoplasty group on follow-up (p = 0.037). Preoperative neurological scores (assessed using the Japanese Orthopaedic Association scale) and improvement on follow-up ≥ 2 years after treatment (average 3.3 years) were not significantly different between the 2 groups; however, there was a significant difference in Japanese Orthopaedic Association score at 4–6 weeks postoperatively (p = 0.047).

Conclusions

Kyphotic deformity and mechanical stress in the cervical spine may play an important role in neurological dysfunction. In a select group of patients with kyphotic deformity ≥ 10°, adequate correction of local sagittal alignment may help to maximize the chance of neurological improvement.

High-resolution magnetic resonance imaging and 18FDG-PET findings of the cervical spinal cord before and after decompressive surgery in patients with compressive myelopathy

STUDY DESIGN

Evaluation of cervical spinal cord (CSC) of patients with compressive myelopathy by magnetic resonance imaging (MRI) and high-resolution (18F)fluoro-deoxyglucose (18FDG) positron emission tomography (PET).

OBJECTIVE

To determine changes in morphology, intramedullary signal intensity, and glucose metabolic rate in CSC after decompression, and to assess the utility of 18FDG-PET in evaluation of patients with cervical myelopathy.

SUMMARY OF BACKGROUND DATA

The significance of CSC enlargement after decompression and signal intensity changes within the cord remain elusive. No data are available on metabolic activity of the compressed CSC. Only a few studies have examined correlation between high-resolution MRI and 18FDG-PET neuroimaging in cervical myelopathy.

METHODS

We studied 24 patients who underwent cervical decompressive surgery in terms of postoperative neurologic improvement and changes in MRI and 18FDG-PET. Neurologic status was assessed by the Japanese Orthopedic Association scoring system (17-point scale). Signal intensity change in the cord was qualitatively assessed on both T1- and T2-weighted images. The transverse area of the CSC on MRIs and glucose metabolic rate (standardized uptake value [SUV]) from 18FDG-PET were measured digitally.

RESULTS

Neurologic improvement correlated with preoperative CSC transverse area at maximal compression (P < 0.01) and at follow-up (P < 0.001) and with mean SUV before surgery (P < 0.01) and at follow-up (P < 0.05). Preoperative signal intensity change on MRIs (low intramedullary signal intensity abnormality on T1-weighted image and high intramedullary on T2-weighted image) correlated negatively with neurologic improvement rate (P < 0.05). The transverse area of the CSC was significantly smaller after surgery in patients with preoperative MRI signal intensity changes (P < 0.05). The SUV at follow-up tended to normalize in association with neurologic improvement.

CONCLUSION

Our results showed that postoperative neurologic improvement in patients with cervical compressive myelopathy correlated with increased transverse area of the spinal cord, signal intensity change on both T1- and T2-weighted image, and the mean SUV.

Measurement of glucose metabolism in rat spinal cord slices with dynamic positron autoradiography

We attempted to measure the regional metabolic rate of glucose (MRglc) in sliced spinal cords in vitro. The thoracic spinal cord of a mature Wister rat was cut into 400-mum slices in oxygenated and cooled (1-4 degrees C) Krebs-Ringer solution. After at least 60 min of preincubation, the spinal cord slices were transferred into double polystyrene chambers and incubated in Krebs-Ringer solution at 36 degrees C, bubbled with 5% O(2)/5% CO(2) gas. To measure MRglc, we used the dynamic positron autoradiography technique (dPAT) with F-18-2-fluoro-2-deoxy-d-glucose ([(18)F]FDG) and the net influx constant of [(18)F]FDG as an index. Uptake curves of [(18)F]FDG were well fitted by straight lines for more than 7 h after the slicing of the spinal cord (linear regression coefficient, r=0.99), indicating a constant uptake of glucose by the spinal cord tissue. The slope (K), which denotes MRglc, is affected by tetrodotoxin, and high K(+) (50 mM) or Ca(2+)-free, high Mg(2+) solution. After 10 min of hypoxia, the K value following reoxygenation was similar to the unloaded control value, but after 45 min of hypoxia, the K value was markedly lower than the unloaded control value, and after >90 min of reoxygenation it was nearly 0. Our results indicate that the living spinal cord slices used retained an activity-dependent metabolism to some extent. This technique may provide a new approach for measuring MRglc in sliced living spinal cord tissue in vitro and for quantifying the dynamic changes in MRglc in response to various interventions such as hypoxia.

Neurological improvement associated with resolution of irradiation-induced myelopathy: serial magnetic resonance imaging and positron emission tomography findings

We document serial magnetic resonance imaging (MRI) and [(18)F] 2-fluoro-2-deoxyglucose (FDG)-positron emission tomography (PET) findings in the process of improvement from delayed radiation necrosis of the spinal cord. A 61-year-old woman underwent radiotherapy for an oral carcinoma. Forty-six months later she developed a left-sided Brown-Séquard syndrome, suggesting incomplete cervical cord transection below the cervico-thoracic junction. Two months after starting steroid therapy, she had gradual clinical improvement, which continues 8 years after the termination of radiotherapy. Neurological improvement was associated with gradual resolution of an extensive high-intensity area within the cervico-thoracic spinal cord on MRI. Initially, the FDG-PET showed linear and uniform increase in FDG uptake throughout the cervical spinal cord with standardized uptake value of 2.68 +/- 0.16 (mean +/- SD), but it returned to normal value (1.90 +/- 0.14) at final follow-up. Considering that the normalization of FDG uptake correlated with neurological recovery, the uniform- and diffuse-increased FDG uptake noted in the initial course of myelopathy could reflect the metabolic activity of the compromised spinal cord.

Ossification of the posterior longitudinal ligament of the cervical spine: histopathological findings around the calcification and ossification front

OBJECT

The authors studied the histological and immunohistochemical features of ossified posterior longitudinal ligament (PLL) of the cervical spine, especially in the calcification and ossification front.

METHODS

Samples of en bloc ossified PLL plaque obtained in 31 patients were stained with H & E and immunohistochemically prepared for collagens (types I and II), vascular endothelial growth factor (VEGF), transforming growth factor (TGF)-beta, and bone morphogenetic protein (BMP)-2, and by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling method for apoptosis.

RESULTS

Enchondral ossification was evident between the ligamentous enthesis and deep layer of the ligament, with irregularly disorganized arrangement of elastic fibers in association with advancement of the degenerative process. In the ossification front, many hypertrophic metaplastic chondrocytes were noted in the ossifying plaque immediately contiguous to the ligament fibers, together with a considerable degree of neovascularization. Both TGFbeta and BMP-2 were highly expressed in metaplastic hypertrophic chondrocytes in the ossification front, and BMP-2 was also expressed in fibroblastic cells near the ossified PLL plaque. Expression of type I collagen was significant in the matrix of the ossified PLL lesion, whereas that of type II was marked in metaplastic chondrocytes in the ossification front. Apoptotic hypertrophic chondrocytes were observed mainly in the fibrocartilaginous area near the calcification front.

CONCLUSIONS

The enchondral ossification process in the ossified PLL was closely associated with degenerative changes of elastic fibers and cartilaginous cartilage formation, together with the appearance of metaplastic hypertrophic cartilage cells and neovascularization. The authors also found that VEGF-positive metaplastic chondrocytes in the ossification front and different expression patterns of collagens probably play some role in the extension of the ossified PLL from the ossification front.

Thoracic ossification of the human ligamentum flavum: histopathological and immunohistochemical findings around the ossified lesion

OBJECT

The object of this study was to histopathologically and immunohistochemically characterize ossification of the ligamentum flavum (OLF) in samples of the thoracic spine harvested en bloc during surgery and to enhance the understanding of the ossifying process, particularly calcification and ossification.

METHODS

Samples of OLF plaque were obtained en bloc from 43 patients who underwent posterior decompression. The histopathological findings were correlated with radiological subtypes using computed tomography. The expression of type I and type II collagens, vascular endothelial growth factor (VEGF), transforming growth factor (TGF)beta, and bone morphogenetic protein (BMP)-2 was investigated.

RESULTS

Surgical decompression using the posterior floating and en bloc resection technique resulted in neurological improvement in 40 of 43 patients. Progression of the OLF lesion longitudinally and medially was associated with significant degeneration of elastic fibers, fiber bundle derangement, decrements in fiber diameter, and fragmentation. Calcification and ossification paralleled the degeneration of the elastic fibers, extended more medially, and fused in the central area. Expression of BMP-2, TGFbeta, and VEGF was significant in chondrocytes in the calcified cartilage and fibrocartilage layers, especially around the calcified front.

CONCLUSIONS

Histopathologically, the progress of calcification and ossification was closely associated with the degeneration of elastic fibers and with significant expression of BMP-2, TGFbeta, and VEGF in the ossification front.

Neuroimaging in traumatic spinal cord injury: an evidence-based review for clinical practice and research

OBJECTIVE

To perform an evidence-based review of the literature on neuroimaging techniques utilized in spinal cord injury clinical practice and research.

METHODS

A search of the medical literature for articles on specific neuroimaging techniques used in SCI resulted in 2,302 published reports. Review at the abstract and full report level yielded 99 clinical and preclinical articles that were evaluated in detail. Sixty nine were clinical research studies subjected to quality of evidence grading. Twenty-three articles were drawn from the pre-clinical animal model literature and used for supportive evidence. Seven review articles were included to add an element of previous syntheses of current thinking on neuroimaging topics to the committee process (the review articles were not graded for quality of evidence). A list of clinical and research questions that might be answered on a variety of neuroimaging topics was created for use in article review. Recommendations on the use of neuroimaging in spinal cord injury treatment and research were made based on the quality of evidence.

RESULTS

Of the 69 original clinical research articles covering a range of neuroimaging questions, only one was judged to provide Class I evidence, 22 provided Class II evidence, 17 Class III evidence, and 29 Class IV evidence.

RECOMMENDATIONS

MRI should be used as the imaging modality of choice for evaluation of the spinal cord after injury. CT and plain radiography should be used to assess the bony anatomy of the spine in patients with SCI. MRI may be used to identify the location of spinal cord injury. MRI may be used to demonstrate the degree of spinal cord compression after SCI. MRI findings of parenchymal hemorrhage/ contusion, edema, and spinal cord disruption in acute and subacute SCI may contribute to the understanding of severity of injury and prognosis for neurological improvement. MRI-Diffusion Weighted Imaging may be useful in quantifying the extent of axonal loss after spinal cord injury. Functional MRI may be useful in measuring the anatomic functional/metabolic correlates of sensory-motor activities in persons with SCI. MR Spectroscopy may be used to measure the biochemical characteristics of the brain and spinal cord following SCI. Intraoperative Spinal Sonography may be used to identify spinal and spinal cord anatomy and gross pathology during surgical procedures. Further research in these areas is warranted to improve the strength of evidence supporting the use of neuroimaging modalities. Positron Emission Tomography may be used to assess metabolic activity of CNS tissue (brain and spinal cord) in patients with SCI.

Targeted retrograde transfection of adenovirus vector carrying brain-derived neurotrophic factor gene prevents loss of mouse (twy/twy) anterior horn neurons in vivo sustaining mechanical compression

STUDY DESIGN

Immunohistochemical analysis after adenovirus (AdV)-mediated BDNF gene transfer in and around the area of mechanical compression in the cervical spinal cord of the hyperostotic mouse (twy/twy).

OBJECTIVE

To investigate the neuroprotective effect of targeted AdV-BDNF gene transfection in the twy mouse with spontaneous chronic compression of the spinal cord motoneurons.

SUMMARY OF BACKGROUND DATA

Several studies reported the neuroprotective effects of neurotrophins on injured spinal cord. However, no report has described the effect of targeted retrograde neurotrophic gene delivery on motoneuron survival in chronic compression lesions of the cervical spinal cord resembling lesions of myelopathy.

METHODS

LacZ marker gene using adenoviral vector (AdV-LacZ) was used to evaluate retrograde delivery from the sternomastoid muscle in adult twy mice (16-week-old) and (control). Four weeks after the AdV-LacZ or AdV-BDNF injection, the compressed cervical spinal cord was removed en bloc for immunohistologic investigation of b-galactosidase activity and immunoreactivity and immunoblot analyses of BDNF. The number of anterior horn neurons was counted using Nissl, ChAT and AChE staining.

RESULTS

Spinal accessory motoneurons between C1 and C3 segments were successfully transfected by AdV-LacZ in both twy and ICR mice after targeted intramuscular injection. Immunoreactivity to BDNF was significantly stronger in AdV-BDNF-gene transfected twy mice than in AdV-LacZ-gene transfected mice. At the cord level showing the maximum compression in AdV-BDNF-transfected twy mice, the number of anterior horn neurons was sinificantly higher in the topographic neuronal cell counting of Nissl-, ChAT-, and AChE-stained samples than in AdV-LacZ-injected twy mice.

CONCLUSION

Targeted AdV-BDNF-gene delivery significantly increased Nissl-stained anterior horn neurons and enhanced cholinergic enzyme activities in the twy. Our results suggest that targeted retrograde AdV-BDNF-gene in vivo delivery may enhance neuronal survival even under chronic mechanical compression.

Cervical angina: a seemingly still neglected symptom of cervical spine disorder?

STUDY DESIGN

Retrospective, case series.

DESIGN

A review of 10 surgical cases with symptoms of cervical angina.

OBJECTIVE

To stress the importance of symptoms of cervical angina in patients with cervical spine disorders.

SETTING

Fukui University Hospital, Japan.

RESULTS

A total of 10 patients complaining of symptoms of cervical angina were admitted with a tentative diagnosis of coronary artery disease. Pain relief was achieved by anterior surgical decompression in all patients.

CONCLUSION

We stress that physicians should be aware of the symptoms of cervical angina and that surgical intervention often leads to complete relief of symptoms.

Cruciate paralysis and hemiplegia cruciata: report of three cases

STUDY DESIGN

Report of three cases of cruciate paralysis and hemiplegia cruciata.

OBJECTIVE

To stress the importance of upper cervical spine lesions causing neurological symptoms and signs.

SETTING

Neuro-orthopedic service, Fukui University Hospital, Japan.

RESULTS

Three patients (all females; one with congenital anomaly at the occiput-atlas level, one with assimilation of the atlas, and one with rheumatoid arthritis-related proliferative synovium) had clinical features of cruciate paralysis and hemiplegia cruciata. All three cases underwent decompressive surgeries.

CONCLUSION

Neurological symptoms and signs of cruciate paralysis and hemiplegia cruciata should be carefully assessed, and surgical therapy should be based on the pathological condition.