Upright, weight-bearing, dynamic-kinetic MRI of the spine: initial results

Can recumbent magnetic resonance imaging replace myelography or computed tomography myelography for detecting lumbar spinal stenosis?

OBJECTIVE

To compare the diagnostic efficacy of recumbent magnetic resonance imaging (MRI), computed tomography myelography (CTM), and myelography, with regard to indications for surgery for lumbar stenosis.

BACKGROUND DATA

In patients with lumbar spinal stenosis-like disorders, small compressions are sometimes observed in magnetic resonance images acquired in the recumbent position, leading to potential misdiagnosis. Few prospective studies have compared the diagnostic accuracy of MRI, myelography, and CTM. Therefore, it is not clear whether myelography is necessary or not.

METHODS

Fifty-four patients fulfilled the criteria. All patients underwent MRI, myelography, and CTM. MRI was performed with the patient in a normal recumbent position, and CTM was performed with the patients in both a recumbent and extended positions. All patients underwent surgery for lumbar spinal stenosis. Findings from visual examinations (sagittal images of MR, axial images of MR, axial reconstruction images of CTM and myelograms) were defined as compression + or -. We analyzed the sensitivity of the different examinations for diagnosis and the relationship among the types of images.

RESULTS

Sensitivity was as follows: CTM 94.4 %, myelography 87.0 %, and MRI 75.9 %. In myelography, the images of 37 patients were worsened by dynamic synthesis (Dyn+). Among patients without compression on MRI, 11 showed compression on myelography. Of these 11, 8 of these patients were Dyn+, and 2 patients showed compression on myelography, but not on CTM and were Dyn+. Thus, some compression can be revealed only with myelography. CTM was more sensitive than axial MRI and showed compression in 12 patients that was not detected by axial MRI.

CONCLUSION

Myelography revealed stenosis that was not detected by MRI. CTM with extension is more sensitive for detecting stenosis than MRI. Recumbent MRI cannot replace myelography or CTM in terms of dynamic findings and sensitivity.

Lumbar spine MRI in upright position for diagnosing acute and chronic low back pain: statistical analysis of morphological changes

Background

Patients with low back pain frequently demonstrate recumbent magnetic resonance imaging (MRI) alterations not always related to homogeneous clinical symptoms. The purpose of this study was to evaluate and quantify the statistical significance of variations of some anatomical parameters of the lumbosacral spine and reveal occult disc pathologies from recumbent to upright position in patients with acute and chronic low back pain.

Materials and methods

Fifty-seven patients complaining of low back pain (27 women, 30 men) underwent dynamic lumbosacral MRI with a 0.25-T tilting system (G-scan Esaote). We settled five parameters for which variations have been evaluated: lumbosacral angle, lordosis angle, L3–L4 intersomatic disc height, L3–L4 interspinous processes distance, and widest anteroposterior dural sac diameter. Images were obtained in both recumbent and upright positions.

Results

Statistically significant differences [one-way analysis of variance (ANOVA), p = 0.0043] were found between each pair of values of parameters sampled in recumbent and upright positions. In 70 % of patients, on visual qualitative analysis only, an increment of disc protrusions and/or spondylolisthesis was found in the upright position; in three cases, in the upright position only, an interarticular pseudocyst was found.

Conclusions

Dynamic MRI with an open-configuration, low-field tilting MRI system is a feasible and promising tool to study degenerative pathology of the spine. Moreover, in cases of low back pain with negative MRI in the recumbent position or in patients with pain in the upright position only, tilting MRI permits visualization of occult spine and disc pathologies in patients with acute or chronic low back pain.

Unsuspected spondylolysis in patients with lumbar disc herniation on MRI: The usefulness of posterior epidural fat

BACKGROUND AND PURPOSE

Lumbar disc herniation (LDH) at the level of non-displaced spondylolysis (isthmic spondylolisthesis) is an uncommon association rarely evaluated in the literature. In this study, authors examine whether the continuous posterior epidural fat between the dura mater and spinous process (continuous double-hump sign) at the level of LDH is a valuable tool to identify patients with non-displaced spondylolysis on MRI.

METHODS

Eighteen patients (group 1) presented at our department (2000-2010) with a LDH associated with an undiagnosed non-displaced spondylolysis on MRI. Spondylolysis was confirmed by direct visualization of the defect on CT-scan, dynamic radiography, MRI or at surgery. To validate this method, we made the same evaluation in 20 surgically treated patients (group 2) with a one-level LDH without spondylolysis.

RESULTS

In all patients of group 1 spondylolysis was unsuspected on the MRI report. However, a positive "continuous double-hump sign" was seen in 16 patients. The spondylolysis was recognized on MRI in six cases, on CT-scan in nine cases and on dynamic radiography in one case. Two cases were diagnosed surgically. In group 2, only one patient had a positive "continuous double-hump sign". This new sign had a specificity of 95%, sensitivity of 88.88%, and accuracy of 92.10% for diagnosis of non-displaced spondylolysis.

CONCLUSIONS

Non-displaced spondylolysis may be associated with adjacent LDH. Although uncommon, it is important for neurosurgeons to be aware of this association because of its implication on the therapeutical management. MRI is not always sufficient to recognize a non-displaced spondylolysis with certainty; however "continuous double-hump sign" may be used as a simple valuable diagnosis tool.

A pilot trial on kinematic magnetic resonance imaging using a superconducting, horizontally opened, 1.2 T magnetic resonance system

Purpose

This study was performed to introduce and evaluate the potential of kinematic magnetic resonance imaging (KMRI) using a high-field open-magnet magnetic resonance (MR) system.

Methods

We attempted to perform KMRI of healthy volunteers’ lumbar spine and knee in the lateral position and ankle in the supine position utilizing the superconducting, horizontally opened, 1.2 T MR system (OASIS, HITACHI, Tokyo, Japan). For the KMRI of the lumbar spine, the volunteer had to lie on one side while maintaining maximally anteflexed, neutral, and maximally retroflexed positions and remain still for the duration of the acquisition time for each posture. In the same way, KMRI of the knee was performed with the volunteer's knee flexed at 0°, 30°, 60°, 90°, and 120° in the lateral position, and KMRI of the ankle was performed with the volunteer's ankle in maximally dorsiflexed, neutral, and maximally plantarflexed positions while lying in the supine position.

Results

We could acquire higher quality kinematic MR images than those acquired using low-field MR systems. The spinal canal, intervertebral discs and foramina, and facet joints in lumbar spine KMRI; the ligaments, menisci and patellofemoral joint in knee KMRI; and the tibiotalar articulation and peroneal tendon in ankle KMRI were clearly depicted.

Conclusion

The results of our pilot trial indicated that a superconducting horizontally opened, 1.2 T MR system offers high-quality KMRI images and can be utilized for the kinematic diagnosis and evaluation of sports injuries.

The influence of morphology on cervical injury characteristics

STUDY DESIGN

Review of peer-reviewed literature.

OBJECTIVE

Outline the effects of neck and cervical spine morphology on soft tissue injury Potential during low velocity automotive rear impacts.

SUMMARY OF BACKGROUND DATA

Automotive rear impacts are mechanical events and the response of the human head-neck complex can be thought of in biomechanical terms. This manuscript reviews evidence from peer-reviewed studies implicating occupant-related factors in the onset and severity of cervical spine soft-tissue injury.

METHODS

Effects of anatomical characteristics, head-neck and spine orientation, facet joints, and neck muscles were reviewed.

RESULTS

On the basis of existing biomechanically based research, the following occupant-related characteristics can influence the response of the cervical spine during automotive rear impacts: anatomical dimensions of the cervical spine, head-neck and cervical spine orientation at the time of impact, facet joint orientation, and neck muscle size and orientation.

CONCLUSION

The response of the cervical spine to rear impacts can be described using biomechanical concepts. This review has identified occupant-related factors that can influence injury susceptibility and cited biomechanically related research to outline the method by which those factors affect the overall head-neck and cervical spine response in such a way as to increase the susceptibility or severity of injury for a given rear impact event.

Spondylolysis and spondylolisthesis: prevalence of different forms of instability and clinical implications

STUDY DESIGN

Imaging study with an evaluation of incidences and clinical correlation.

OBJECTIVE

To evaluate the incidence of 3 different types of instabilities in patients with spondylolysis or isthmic spondylolisthesis. Clinical findings are correlated with imaging findings, and the imaging findings are analyzed with regard to their clinical implications.

SUMMARY OF BACKGROUND DATA

Spondylolysis and isthmic spondylolisthesis are common disorders. An unstable slip is the most well-known form of instability, but other forms also exist. However, the incidence of these instabilities and their clinical implications are yet unclear.

METHODS

A total of 140 patients with 141 levels of spondylolysis identified by MRI (magnetic resonance imaging) were included in this study. Using positional MRI, the instability of the slip, an increased angular movement, and movement in the spondylolytic cleft were assessed. On the basis of clinical findings, the patients were classified as presenting with either radicular or nonradicular symptoms. The incidence of the instabilities was recorded and correlated with the incidence of radicular symptoms.

RESULTS

Fifteen patients had an unstable slip (anterior instability); 35, an increased angular movement (angular instability); and 34 patients, a movement in the spondylolytic cleft (posterior instability). All forms of instability could be found together. No instability at all was found in 76 patients. Radicular symptoms were found significantly more often in patients with one or more of the described instabilities compared with patients without instability.

CONCLUSION

All 3 described forms of instability are common in spondylolysis or isthmic spondylolisthesis and associated with radicular pain. This finding stresses the value of positional MRI in the evaluation of patients with spondylolysis and isthmic spondylolisthesis, especially if radicular symptoms are present.

Lumbar spinal stenosis with exacerbation of back pain with extension: a potential contraindication for supine MRI with sedation

A 71-year-old male with lumbar spinal stenosis developed exacerbation of lower back pain and leg paresthesias while attempting to undergo a spinal magnetic resonance imaging (MRI) scan in the supine position. After undergoing sedation for the MRI, he developed an acute cauda equina syndrome that required surgical decompression. MRI may be contraindicated in the supine position for patients with spinal stenosis and back pain exacerbated by mild-to-moderate extension, since it may further compress the neural tissue.

Role of imaging in spine, hand, and wrist osteoarthritis

Osteoarthritis (OA) of the wrist is mainly secondary to traumatic ligamentous or bone injuries. Involvement of the radiocarpal joint occurs early on in the disease, whereas the mediocarpal joint is involved at a later stage. Metabolic diseases may also involve the wrist and affect specific joints such as the scapho-trapezio-trapezoid joint. Although OA of the wrist is routinely diagnosed on plain films, a thorough assessment of cartilage injuries on computed tomographic arthrography, magnetic resonance imaging (MRI), or MR arthrography remains necessary before any surgical procedure. OA of the fingers is frequently encountered in postmenopausal women. Distal interphalangeal joints and trapezio-metacarpal joint are the most frequently involved joints. Whereas the clinical diagnosis of OA of the wrist and hand is straightforward, the therapeutic management of symptomatic forms remains unclear, with no clear guidelines. OA of the spine is related to degenerative changes of the spine involving the disc space, vertebral endplates, the facet joints, or the supportive and surrounding soft tissues. The sequelae of disc degeneration are among the leading causes of functional incapacity in both sexes, and are a common source of chronic disability in the working years. Disc degeneration involves structural disruption and cell-mediated changes in composition. Radiography remains usually the first-line imaging method. MRI is ideally suited for delineating the presence, extent, and complications of degenerative spinal disease. Other imaging modalities such as computed tomography, dynamic radiography, myelography, and discography may provide complementary information in selected cases, especially before an imaging-guided percutaneous treatment or spinal surgery. The presence of degenerative changes on imaging examinations is by no means an indicator of symptoms, and there is a high prevalence of lesions in asymptomatic individuals. This article focuses on imaging of OA of the wrist and hand, as well as lumbar spine OA, with an emphasis on current MRI grading systems available for the assessment of discovertebral lesions.

Lumbar segmental mobility according to the grade of the disc, the facet joint, the muscle, and the ligament pathology by using kinetic magnetic resonance imaging

STUDY DESIGN

The kinematic study of human lumbar spinal movements.

OBJECTIVE

To investigate how disc degeneration and the degeneration of facet joint, ligaments, and paraspinal muscles are associated with lumbar segmental mobility.

SUMMARY OF BACKGROUND DATA

Previous studies revealed relationship between spinal motion and osteoarthritic changes of facet joint as well as disc degeneration; however, little is known about the association of disc, facet joint, ligament, and muscle degeneration with lumbar segmental motion characteristics.

METHODS

The 1580 lumbar motion segments from 316 patients (200 male, 116 female) underwent Kinetic magnetic resonance imaging, which were used to assess disc degeneration (grade I-V) and facet joint degeneration (grade 1-4), interspinous ligament (ISL) degeneration (grade 1-4), ligamentum flavum hypertrophy (LFH), and fatty degeneration of muscles. Segmental translational and angular motion in the flexion, extension, and neutral postures were digitally automatically measured by MR analyzer.

RESULTS

Grade II (46.77%) disc, grade 1 (48.35%) facet joint degeneration, and grade 1 (64.1%) ISL were most common. LFH was most common in L4-L5 (49/330, 14.8%). In younger age (<35), grade I disc and grade 1 facet joint were predominant compared with the older age (35< or = and <45) in which grade III, IV, and V disc and grade 2 facet joint were predominant (P < 0.05). Translational motion increased significantly in high grade of disc and facet joint (except grade V disc and grade 4 facet joint) and with LFH in L1-L5 (P < 0.05). Angular motion significantly decreased in grade V disc, grade 4 ISL, and without LFH in L1-L5 (P < 0.05). According to muscle fatty degeneration, translational and angular motions were not significantly changed.

CONCLUSION

Our results support that facet joint degeneration is followed by disc degeneration according to age. Increased translational movements of the lumbar segments occurred in severe disc degeneration accompanied by facet joint degeneration or the presence of LFH even if the movements were stabilized in the advanced status. Therefore, the current status of the intervertebral discs, facet joints, and ligamentum flavum should be taken into consideration when evaluating stability within the lumbar spine.

Dynamic lumbar spinal stenosis : the usefulness of axial loaded MRI in preoperative evaluation

Two cases of dynamic lumbar spinal stenosis were identified by the authors using axial loaded magnetic resonance image (MRI). In both cases, the patients presented with neurogenic claudication but MRI in decumbency showed no definite pathologic condition associated with their symptoms. In contrast, axial loaded MRI demonstrated constrictive spinal stenosis and a significantly decreased dural sac caused by epidural fat buckling and thickening of the ligamentum flavum in both cases. In the second case, a more prominent disc protrusion was also demonstrated compared with decumbent MRI. After decompressive surgery, both patients had satisfactory outcomes. Axial loaded MRI can therefore give decisive information in dynamic spinal disorders by allowing simulation of an upright position.

Imaging‐based planning for spine surgery

The planning of decompressive and reconstructive spine surgery is based on clinical findings and diagnostic imaging. The evaluation of segmental instability, but also of the risk of destabilization following a needed decompression of the spinal canal and/or neural foramina make complex spine surgery a challenge, bearing in mind the risk of failures in case of an inadequate operation. The insufficient correlation between imaging and clinical symptoms originating from the spine and its nerve roots has been frustrating for some decades. This review focuses on the new upright, dynamic-kinetic, i.e., "functional" MRI and its ability to detect load- and motion-dependent disc herniations, stenosis, instabilities, and combinations of these pathologies not seen during recumbent imaging.

Segmental in vivo vertebral motion during functional human lumbar spine activities

Quantitative data on the range of in vivo vertebral motion is critical to enhance our understanding of spinal pathology and to improve the current surgical treatment methods for spinal diseases. Little data have been reported on the range of lumbar vertebral motion during functional body activities. In this study, we measured in vivo 6 degrees-of-freedom (DOF) vertebral motion during unrestricted weightbearing functional body activities using a combined MR and dual fluoroscopic imaging technique. Eight asymptomatic living subjects were recruited and underwent MRI scans in order to create 3D vertebral models from L2 to L5 for each subject. The lumbar spine was then imaged using two fluoroscopes while the subject performed primary flexion-extension, left-right bending, and left-right twisting. The range of vertebral motion during each activity was determined through a previously described imaging-model matching technique at L2-3, L3-4, and L4-5 levels. Our data revealed that the upper vertebrae had a higher range of flexion than the lower vertebrae during flexion-extension of the body (L2-3, 5.4 +/- 3.8 degrees ; L3-4, 4.3 +/- 3.4 degrees ; L4-5, 1.9 +/- 1.1 degrees , respectively). During bending activity, the L4-5 had a higher (but not significant) range of left-right bending motion (4.7 +/- 2.4 degrees ) than both L2-3 (2.9 +/- 2.4 degrees ) and L3-4 (3.4 +/- 2.1 degrees ), while no statistical difference was observed in left-right twisting among the three vertebral levels (L2-3, 2.5 +/- 2.3 degrees ; L3-4, 2.4 +/- 2.6 degrees ; and L4-5, 2.9 +/- 2.1 degrees , respectively). Besides the primary rotations reported, coupled motions were quantified in all DOFs. The coupled translation in left-right and anterior-posterior directions, on average, reached greater than 1 mm, while in the proximal-distal direction this was less than 1 mm. Overall, each vertebral level responds differently to flexion-extension and left-right bending, but similarly to the left-right twisting. This data may provide new insight into the in vivo function of human spines and can be used as baseline data for investigation of pathological spine kinematics.

The Preoperative Spine: Diagnostic Work up with fMRI

The advantages of the upright, open, multi-positional MRI, i.e. functional MRI (fMRI) are presented with illustrative cases and the literature is reviewed. In cases of not explained and especially in position-dependent spinal and/or neurological pain and/or dysfunction functional or dynamic MRI is able to reveal dynamic compressions/stenosis, as well as segmental dysfunction and instabilities in a noninvasive way. This new technology could become mandatory for the preoperative investigation of unexplained, mainly "dynamic, mobile or unstable" spinal pathologies. Allowing a better correlation of signs and symptoms with the imaging findings and thus a more targeted treatment, fMRI could help to decrease the rate of failed back surgery syndrome in the near future.

Use of stand-up magnetic resonance imaging for evaluation of a cervicothoracic injury in a patient with ankylosing spondylitis

BACKGROUND CONTEXT

Injuries at the cervicothoracic junction are common in patients with ankylosing spondylitis. These injuries present challenges for both initial and follow-up imagings.

PURPOSE

To describe a case of a patient with ankylosing spondylitis who was treated with laminectomy and a cervicothoracic orthosis for a spinal epidural hematoma after a nondisplaced fracture at the cervicothoracic junction and to discuss the merits of stand-up magnetic resonance imaging (MRI) for follow-up evaluation of this type of injury.

STUDY DESIGN/SETTING

Case report.

METHODS

Clinical data of a patient with ankylosing spondylitis who sustained a nondisplaced C7 fracture are presented, followed by a detailed review of the literature concerning imaging techniques available for the evaluation of cervical spine trauma in this patient population.

RESULTS

The patient was treated with emergent laminectomy and evacuation of the epidural hematoma, followed by definitive management in a cervicothoracic orthosis secondary to medical comorbidities. The patient was then successfully followed postoperatively with stand-up MRI because conventional imaging techniques could not adequately image the injury level in an upright position.

CONCLUSIONS

Cervicothoracic injuries are common in patients with ankylosing spondylitis and may be difficult to follow with conventional imaging techniques. Stand-up MRI is a relatively new modality that may offer significant advantages over conventional imaging because of the ability to evaluate the cervicothoracic junction in a more functional position and the lack of a confining space such as that found in standard MRI units.

Whole-spine dynamic magnetic resonance study of contortionists: anatomy and pathology

OBJECT

Whole-spine magnetic resonance (MR) images were obtained using a cylindrical 3-T MR imaging system in 5 contortionists to assess the pathological changes possibly associated with the practice of contortion. Whole-spine dynamic MR images were obtained using a 1-T open MR imaging system in 2 of these contortionists with the purpose of defining the range of motion (ROM) achieved during extreme contortion. The range of spinal motion in this unique population was then quantified.

METHODS

The study included 5 female contortionists 20-49 years of age. Imaging was performed using open 1-T and cylindrical 3-T high-field MR imaging systems. Data were viewed and analyzed with DICOM-compliant tools. Real-time, dynamic, and standard MR imaging allowed for quantification of the contortionists' ROM.

RESULTS

There was a difference of 238 degrees between full spinal extension and full flexion. Three of the 5 contortionists had 4 anterosuperior limbus vertebrae at T-11 and the upper lumbar levels.

CONCLUSIONS

Whole-spine dynamic MR imaging is a valuable tool for the evaluation of the extreme ROM in contortionists, allowing for the quantification of extreme mobility. The limbus fractures present in 3 of the 5 contortionists is postulated to be due to avulsion on hyperextension. Future research may open the use of whole-spine dynamic MR imaging into such areas as pain management and traumatic spinal injuries.

Posture-dependent human 3He lung imaging in an open-access MRI system: initial results

RATIONALE AND OBJECTIVES

The human lung and its functions are extremely sensitive to orientation and posture, and debate continues as to the role of gravity and the surrounding anatomy in determining lung function and heterogeneity of perfusion and ventilation. However, study of these effects is difficult. The conventional high-field magnets used for most hyperpolarized (3)He magnetic resonance imaging (MRI) of the human lung, and most other common radiologic imaging modalities including positron emission tomography and computed tomography, restrict subjects to lying horizontally, minimizing most gravitational effects.

MATERIALS AND METHODS

In this article, we review the motivation for posture-dependent studies of human lung function and present initial imaging results of human lungs in the supine and vertical body orientations using inhaled hyperpolarized (3)He gas and an open-access MRI instrument. The open geometry of this MRI system features a "walk-in" capability that permits subjects to be imaged in vertical and horizontal positions and potentially allows for complete rotation of the orientation of the imaging subject in a two-dimensional plane.

RESULTS

Initial results include two-dimensional lung images acquired with approximately 4 x 8 mm in-plane resolution and three-dimensional images with approximately 2-cm slice thickness.

CONCLUSIONS

Effects of posture variation are observed, including posture-related effects of the diaphragm and distension of the lungs while vertical.

Imaging in the position that causes pain

BACKGROUND

Magnetic resonance imaging has the diagnostic advantages of being noninvasive and able to visualize soft tissue. However, conventional recumbent MRI may underestimate a disease because the position of imaging takes stress off the spine.

CASE DESCRIPTION

A 37-year-old woman presented with complaints of pain in the neck that radiated down her right arm when she turned her head to the right and increased with extension. She complained of paresthesias, numbness/tingling in the index and middle fingers and thumb, in the C6 and C7 nerve root dermatomes. Conventional conservative measures, including anti-inflammatories, muscle relaxants, opiates, and physical therapy, had been tried without positive results. Magnetic resonance imaging was performed in a weight-bearing upright neutral position, in the extended upright position, and in the extended upright position with the head turned to the right. The latter images showed a clear protrusion at C5-C6 and C6-C7. These protrusions were not clearly evident in the upright neutral position. A targeted epidural block at C5-C6 and C6-C7 relieved the patient's pain, and she has been able to continue work.

CONCLUSIONS

Magnetic resonance imaging of the cervical spine in the position that causes the patient's symptoms may increase the sensitivity and accuracy of the diagnostic study and thus provide the spine-care professional with a potentially more accurate diagnosis and a targeted treatment plan. Such MRIs may also decrease the need for myelography.

Upright positional MRI of the lumbar spine

Supine magnetic resonance imaging (MRI) is routinely used in the assessment of low back pain and radiculopathy. However, imaging findings often correlate poorly with clinical findings. This is partly related to the positional dependence of spinal stenosis, which reflects dynamic changes in soft-tissue structures (ligaments, disc, dural sac, epidural fat, and nerve roots). Upright MRI in the flexed, extended, rotated, standing, and bending positions, allows patients to reproduce the positions that bring about their symptoms and may uncover MRI findings that were not visible with routine supine imaging. Assessment of the degree of spinal stability in the degenerate and postoperative lumbar spine is also possible. The aim of this review was to present the current literature concerning both the normal and symptomatic spine as imaged using upright MRI and to illustrate the above findings using clinical examples.

Discrepancies of MRI findings between recumbent and upright positions in atlantoaxial lesion. Report of two cases

Two cases of atlantoaxial (A-A) instability that showed different MRI findings between supine and upright positions are presented. The upright MRI represented the findings corresponding to their symptoms. In A-A lesions, conventional MR images taken in the supine position do not always explain the pathophysiological consequences. The MR images taken in the upright position disclose the actual spinal pathophysiology with gravitational effects.

Upright MRI of glenohumeral dysplasia following obstetric brachial plexus injury

The purpose of this study was to evaluate the role of upright magnetic resonance imaging (MRI) shoulder scanning in the diagnosis of glenohumeral deformity following obstetric brachial plexus injury (OBPI). Eighty-nine children (ages 0.4 to 17.9 years) with OBPI who have medial rotation contracture and reduced passive and active lateral rotation of the shoulder were evaluated via upright MRI of the affected glenohumeral joint. Qualitative impressions of glenoid form were recorded, and quantitative measurements were made of glenoid version and posterior subluxation. Glenoid version of the affected shoulder averaged -16.8 +/- 11.0 degrees (range, -55 degrees to 1 degrees ), and percentage of the humeral head anterior to the glenoid fossa (PHHA) averaged 32.6 +/- 16.5% (range, -17.8% to 52.4%). The glenoid form was normal in 43 children, convex in 19 children and biconcave in 27 children. Standard MRI protocols were used to obtain bilateral images from 14 of these patients. Among the patients with bilateral MR images, glenoid version and PHHA were significantly different between the involved and uninvolved shoulders (P<.000). Glenoid version in the involved shoulder averaged -19.0 +/- 13.1 degrees (range, -52 degrees to -3 degrees ), and PHHA averaged 29.7 +/- 18.4% (range, -16.2% to 48.7%). In the uninvolved shoulder, the average glenoid version and PHHA were -5.2 +/- 3.7 degrees (range, -12 degrees to -1 degrees ) and 47.7 +/- 3.0% (range, 43% to 54%), respectively. The relative beneficial aspects of upright MRI include lack of need for sedation, low claustrophobic potential and, most important, natural, gravity-influenced position, enabling the surgeon to visualize the true preoperative picture of the shoulder. It is an effective tool for demonstrating glenohumeral abnormalities resulting from brachial plexus injury worthy of surgical exploration.

Lumbar degenerative disk disease

The sequelae of disk degeneration are among the leading causes of functional incapacity in both sexes and are a common source of chronic disability in the working years. Disk degeneration involves structural disruption and cell-mediated changes in composition. Mechanical, traumatic, nutritional, and genetic factors all may play a role in the cascade of disk degeneration, albeit to variable degree in different individuals. The presence of degenerative change is by no means an indicator of symptoms, and there is a very high prevalence in asymptomatic individuals. The etiology of pain as the symptom of degenerative disease is complex and appears to be a combination of mechanical deformation and the presence of inflammatory mediators. The role of imaging is to provide accurate morphologic information and influence therapeutic decision making. A necessary component, which connects these two purposes, is accurate natural history data. Understanding the relationship of etiologic factors, the morphologic alterations, which can be characterized with imaging, and the mechanisms of pain production and their interactions in the production of symptoms will require more accurate and reproducible stratification of patient cohorts.

Dynamic magnetic resonance imaging of the cervical spine using the NeuroSwing System

OBJECTIVE

Routine MR examinations of the cervical spine might be insufficient in the diagnosis of a stenotic problem of the spinal canal, especially when symptoms only occur in a specific position. Latest developments enable real-time dynamic MR examinations in the neutral position as well as anteflexion and retroflexion using a dynamic instrumentation system designed for the cervical spine. We report our experience using the dynamic NeuroSwing System.

MATERIALS AND METHODS

Twenty patients with symptoms of cervical spinal stenosis were included. All examinations were performed using a 1.5 Tesla MR scanner. The patients were measured in the neutral position, and in dynamic anteflexion and retroflexion. Patients set their individual limits of movement interactively during the scan. The dynamic scans were performed within 51 seconds using a real-time TrueFisp (steady-state free precession) sequence with a slice thickness of 4 mm and a temporal resolution of 2.5 images per second.

RESULTS

The averaged anteflexion and retroflexion were 42.3 degrees and 47.25 degrees, respectively. An increase in spinal stenosis during movement was found in 5 patients.

CONCLUSION

Real-time dynamic examination of the cervical spine might be a useful supplement to the conventional static examination and may allow a more precise allocation of symptoms in some patients.

Imaging the degenerative diseases of the lumbar spine

Degenerative changes of the spine may involve the disc space, the facet joints, or the supportive and surrounding soft tissues. MR imaging is ideally suited for delineating the presence, extent, and complications of degenerative spinal disease. Other imaging modalities such as radiography, myelography, and CT may provide complimentary information in selected cases. Percutaneous procedures may be used to confirm that a morphologic abnormality is the source of symptoms. Correlation with clinical and electrophysiologic data is also helpful for accurate diagnosis. Combining the information obtained from imaging studies with the patient's clinical presentation is mandatory for determining the appropriate patient management strategy, especially true in patients afflicted with any condition directly attributed to the degenerative processes of the spine.

Evaluation of intervertebral disc herniation and hypermobile intersegmental instability in symptomatic adult patients undergoing recumbent and upright MRI of the cervical or lumbosacral spines

PURPOSE

The purpose of the study was to determine the difference in findings between recumbent and upright-sitting MRI of the cervical and lumbosacral spine in patients with related sign and symptoms.

MATERIALS AND METHODS

A total of 89 patients were studied (lumbosacral spine: 45 patients; cervical: 44 patients). T1-weighted (TR: 350, TE: 20) fast spin echo and T2-weighted (TR: 2500, TE: 160) fast spin echo images were acquired in the sagittal and axial planes in both the recumbent and sitting-neutral positions. The images were acquired on the Upright MRI unit (Fonar Corporation, Melville, NY). Differences were sought between the recumbent and upright-sitting positions at all levels imaged, in both planes.

RESULTS

The total number of cases of pathology was 68, including instances of posterior disc herniation and anterior and posterior spondylolisthesis. Focal posterior disc herniations were noted in 55 patients (cervical: 31, lumbosacral: 24) [62% of patients]. Six of these herniations (cervical: 4, lumbosacral: 2) [11%] were seen only on the upright-sitting study. Focal posterior disc herniations were seen to comparatively enlarge in size in 35 patients on the upright-seated examination (cervical: 21, lumbosacral: 14) [72%], and reduce in size in 9 patients (cervical: 5, lumbosacral: 4) [18%]. Degenerative anterior (n: 11) and posterior (n: 2) spondylolisthesis was seen in 13 patients (cervical: 0, lumbosacral: 13) [15% of patient total]. Anterior spondylolisthesis was only seen on the upright-seated examination in 4 patients (cervical: 0, lumbosacral: 4) [31%]. Anterior spondylolisthesis was comparatively greater in degree on the upright-seated study in 7 patients (cervical: 0, lumbosacral: 7) [54%]. Posterior spondylolisthesis was comparatively greater in degree on the recumbent examination in 2 patients (cervical: 0, lumbosacral: 2) [15%]. The overall combined recumbent miss rate in cases of pathology was 15% (10/68). The overall combined recumbent underestimation rate in cases of pathology was 62% (42/68). The overall combined upright-seated underestimation in cases of pathology was 16% (11/69).

CONCLUSIONS

Overall, upright-seated MRI was found to be superior to recumbent MRI of the spine in 52 patents (recumbent missed pathology [n: 10]+recumbent underestimated pathology [n: 42]=52/89 total patients: 58%) in cases of posterior disc herniation and anterior spondylolisthesis. This seems to validate the importance of weight-bearing imaging in the spine that might be expected to unmask positional enlarging disc herniations and worsening spondylolisthesis. Overall, recumbent MRI was found to be superior to upright-seated MRI in 11 cases (11/89: 12%). The latter finding was possibly due to the fact that upright seated position is actually partial flexion that might be expected to reduce some cases of hypermobile posterior spondylolisthesis.

Spinal injury in sport

Spinal injuries are very common among professional or amateur athletes. Spinal sport lesions can be classified in overuse and acute injuries. Overuse injuries can be found after years of repetitive spinal load during sport activity; however specific overuse injuries can also be found in adolescents. Acute traumas are common in contact sports. Most of the acute injuries are minor and self-healing, but severe and catastrophic events are possible. The aim of this article is to review the wide spectrum of spinal injuries related to sport activity, with special regard to imaging finding.

Degenerative Disease of the Spine

Degenerative disease of the spine is a definition that includes a wide spectrum of degenerative abnormalities. Degeneration involves bony structures and the intervertebral disk, although many aspects of spine degeneration are strictly linked because the main common pathogenic factor is identified in chronic overload. During life the spine undergoes continuous changes as a response to physiologic axial load. These age-related changes are similar to pathologic degenerative changes and are a common asymptomatic finding in adults and elderly persons. A mild degree of degenerative changes is paraphysiologic and should be considered pathologic only if abnormalities determine symptoms. Imaging allows complete evaluation of static and dynamic factors related to degenerative disease of the spine and is useful in diagnosing the different aspects of spine degeneration.

Multilevel cervical spondylosis

Multilevel cervical spondylosis is a common disorder encountered by most actively practicing spine surgeons. Patients can present with a combination of complaints, including mechanical neck pain, radiculopathy, and myelopathy. A comprehensive evaluation is required for appropriate diagnosis and treatment. Accurate interpretation of imaging techniques, including plain x-rays, CT, and MRI, is necessary to formulate the optimal surgical strategy. Key points to address during construction of the operative plan include the direction of approach, the extent of the decompression, and the type of stabilization construct when necessary. This article outlines various techniques to facilitate operative planning, optimize the surgical objective, and minimize potential complications.

The value of fat saturation sequences and contrast medium administration in MRI of degenerative disease of the posterior/perispinal elements of the lumbosacral spine

Degenerative-inflammatory lumbar spinal pathology is one of the most common reasons why individuals seek medical care, and low back pain is the main symptom among those most commonly associated with this pathologic condition. Pain is commonly attributed to degenerative disc disease, particularly herniated discs, but many different spinal and perispinal structures may undergo degenerative-inflammatory phenomena and produce pain: discs, bone, facet joints, ligaments and muscles. In particular, in patients with non-radicular low back pain, this syndrome may arise from changes of the posterior elements/perispinal tissues of the lumbar spine (i.e., the "posterior vertebral compartment"). They include: facet joint pathology (e.g., osteoarthritis, joint effusion, synovitis and synovial cysts), spondylolysis, spinal/perispinal ligamentous degenerative-inflammatory changes and perispinal muscular changes. It is well known that magnetic resonance is the most sensitive imaging method for the evaluation of spinal degenerative pathology, even in the initial stages of the disease. T2-weighted sequences with fat saturation, and when indicated the use of contrast-enhanced T1-weighted images with fat saturation, permit the visualization of degenerative-inflammatory changes of the posterior elements of the lumbar spine that in most cases would have been overlooked with conventional non-fat suppressed imaging.