In a study of 59 patients surgically treated by various surgeons for relief of herniated lumbar intervertebral disc accompanied by symptoms that persistently recurred or had become resistant to conservative therapy, it was noted from review of hospital and office records that laminectomy either greatly relieved or entirely abated symptoms in 83 per cent of the cases.
Postoperative complications reported by the surgeons who did the operations consisted of one death and five wound infections. Contrast myelography and electromyography, used in almost all cases in the series, appeared to be valuable adjuncts in the diagnosis of herniated lumbar intervertebral discs. The most common site of the lesion in this series was between the fourth and fifth lumbar vertebrae. Strain upon lifting was the most commonly reported precipitating factor.
The authors describe a new computerized tomography (CT) myelography technique with coronal and oblique coronal view to demonstrate the status of the cervical nerve rootlets involved in brachial plexus injury. They discuss the value of this technique for diagnosis of nerve root avulsion compared with CT myelography with axial view.
CT myelography was performed with penetration of the cervical subarachnoid space by the contrast medium. Then the coronal and oblique coronal reconstructions were created. The results of CT myelography were evaluated and classified with presence of pseudomeningocele, intradural ventral nerve rootlets, and intradural dorsal nerve rootlets. The diagnosis was by extraspinal surgical exploration with or without spinal evoked potential measurements and choline acetyl transferase activity measurement in 25 patients and recovery by a natural course in 3 patients. Its diagnostic accuracy was compared with that of CT myelography with axial view, correlated with surgical findings or a natural course in 57 cervical roots in 28 patients.
Coronal and oblique coronal views were superior to axial views in visualization of the rootlets and orientation of the exact level of the root. Sensitivity and specificity for coronal and oblique coronal views of unrecognition of intradural ventral and dorsal nerve root shadow without pseudomeningocele in determining pre-ganglionic injury were 100% and 96%, respectively. There was no statistically significant difference between coronal and oblique coronal views and axial views.
The information by the coronal and oblique coronal slice CT myelography enabled the authors to assess the rootlets of the brachial plexus and provided valuable data for helping to decide whether to proceed with exploration, nerve repair, primary reconstruction.
A prospective study of 80 patients suffering from sciatica was conducted at Fauji Foundation Hospital, Rawalpindi, Pakistan.
The aim of this study was to select patients for lumbar myelography on clinical grounds in the absence of magnetic resonance
imaging (MRI)/computerized tomography (CT) facilities and to know the causes of sciatica.
Materials and Methods:
All patients underwent conventional lumbar myelography due to lack of MRI facility at a local
hospital as well as financial constraints. Myelography was done with radio-opaque dye, Iopamidol, on outpatient basis
Lumbar myelograms were positive in 77.5% and negative in 22.5% cases. Minor complications in the form of headache developed in 32.5% patients but no major complication like meningitis and archnoiditis developed. Lumbar disc prolapse and stenosis were found to be common causes of sciatica. Non-filling of nerve roots was seen in 33.87%, blocks (complete/partial) in 54.83%, and stenosis in 11.29% patients.
Conventional myelography was found to be safe and an informative diagnostic technique in areas where facility of high-tech investigations like CT/MRI was not available. Conventional lumbar myelography could be recommended and performed with confidence on outdoor basis, in cases of sciatica with positive straight leg raising test, reflex loss, sensory, or motor deficit.
Complications; iopamidol; lumbar disc; myelography; sciatica
Sciatica is commonly caused by lumbar prolapsed intervertebral disc (PID) and other spinal lesions. Uncommon causes like nerve root schwannoma are rarely considered in the differential diagnosis of sciatica. Spinal schwannomas occur both sporadically and in association with neurofibromatosis type 1 (NF1; von Recklinghausen's disease).
This case report describes lumbar foraminal schwannoma as an unusual cause of radiculopathy, presenting clinically as a lumbar disc prolapse. The diagnosis was confirmed on MRI scan. Patient had complete symptomatic recovery following surgical enucleation of the tumour mass from the L5 nerve root. This case report is of particular interest as it highlights the diagnostic confusion, which is bound to arise, because the clinical presentation closely mimics a lumbar PID. This often leads to delay in diagnosis and “failure of conservative treatment.”
Perineurial cysts may be responsible for clinical symptoms and a cure effected by their removal. They do not fill on initial myelography but may fill with Pantopaque some time, days or weeks, after Pantopaque has been instilled into the subarachnoid space. Perineurial cysts arise at the site of the posterior root ganglion. The cyst wall is composed of neural tissue. When initial myelography fails to reveal an adequate cause for the patient's symptoms and signs referable to the caudal nerve roots, then about a millilitre of Pantopaque should be left in the canal for delayed myelography which may later reveal a sacral perineurial cyst or, occasionally, a meningeal cyst. Meningeal diverticula occur proximal to the posterior root ganglia and usually fill on initial myelography. They are in free communication with the subarachnoid space and are rarely in my experience responsible for clinical symptoms. Meningeal diverticula and meningeal cysts appear to represent a continuum. Pantopaque left in the subarachnoid space may convert a meningeal diverticulum into an expanding symptomatic meningeal cyst, as in the case described. Many cases described as perineurial cysts represent abnormally long arachnoidal prolongations over nerve roots or meningeal diverticula. In general, neither of the latter is of pathological significance. Perineurial, like meningeal cysts and diverticula, may be asymptomatic. They should be operated upon only if they produce progressive or disabling symptoms or signs clearly attributable to them. When myelography must be done, and this should be done only as a preliminary to a probable necessary operation, then patient effort should be made to remove the Pantopaque.
In a prospective study, patients with known malignant disease who were suspected of having a spinal epidural metastasis, had myelography which was not confined to the clinically suspected site, but included at least the whole lumbar and thoracic spinal canal. Fifty four of the 106 myelograms revealed at least one epidural metastasis. Twelve of these 54 myelograms showed two separate lesions, and four myelograms showed three separate lesions. In all 16 cases with multiple lesions at least one of the lesions was asymptomatic at the time of the diagnosis. It is concluded that multiple spinal epidural metastases are of common occurrence and occur in about one third of the cases. This finding may have important clinical implications. Examination of the spinal canal for epidural metastases should not be confined to the clinically suspected site, but should include as extensive an area as possible of the spinal canal, whatever technique is to be used.
One hundred and two patients with suspected cervical spondylotic myelopathy were prospectively investigated using MRI as the initial imaging technique. The aim was to discover if clinicians could manage patients with MRI alone, or if they would find a second investigation necessary. Eighty two patients were managed using MRI alone, 34 of whom were treated surgically. Twenty patients had a second investigation: a myelogram in 18 and a CT myelogram in two. This was performed in nine patients to exclude structural pathology in the thoracic or lumbar region (which was not examined with MRI), and in 11 to obtain more specific information about the cervical region. Only five of these 20 patients had surgical treatment. The diagnosis changed after the second investigation in four patients, but management was not influenced in any of these. MRI is a satisfactory alternative to myelography for most patients with suspected cervical spondylotic myelopathy.
Magnetic resonance myelography (MRM) after lumbar discectomy is all too often an unrewarding challenge. A constellation of findings are inevitable, and determining their significance is often difficult. MRM is a noninvasive technique that can provide anatomical information about the subarachnoid space. Until now, there is no study reported in literature showing any clinico-radiological correlation of post operative MRM. The objective of this study was to prospectively evaluate the diagnostic effectiveness of MRM for the demonstration of decompression in operated discectomy patients and its correlation with subjective and objective outcome (pain and SLR) in immediate postoperative period.
Materials and Methods:
Fifty three patients of single level lumbar disc herniation (LDH) justifying the inclusion criteria were operated for discectomy. All patients underwent MRM on second/third postoperative day. The pain relief and straight leg raise sign improvement was correlated with the postoperative MRM images to group the patients into: A- Subjective Pain relief, SLR improved and MRM image showing myelo regression; B- Subjective Pain relief, SLR improved and MRM image showing no myelo regression; C- No Subjective Pain relief, no SLR improved and MRM image showing myelo regression and; D- No Subjective Pain relief, no SLR improved and MRM image showing no myelo regression.
The result showed that Group A had 46 while Group B, C and Group D had 4, 2 and one patients respectively. Clinico-radiological correlation (Clinically diagnosed patient and findings with MRM correlation) was present in 47 patients (88.68%) which includes both A and D groups. The MRM specificity and sensitivity were 92% and 33.33% respectively.
MRM is a non-invasive, efficient and reliable tool in confirming postoperative decompression in lumbar discectomy patients, especially when economic factors are to be considered and the required expertise to reliably read a complex confusing post-operative MRI is not available readily. Further, controlled double blinded multicentric study in operated and non operated LDH, with MRI comparison would give better evidence to justify its use in screening to detect persisting compression and to document decompression.
Discectomy; lumbar disc herniation; magnetic resonance myelography
This study was undertaken to compare the diagnostic performances of magnetic resonance imaging (MRI), MR myelography (MRM) and myelography in young soldiers with a herniated lumbar disc (HLD).
Sixty-five male soldiers with HLD comprised the study cohort. A visual analogue scale for low back pain (VAS-LBP), VAS for leg radiating pain (VAS-LP), and Oswestry disability index (ODI) were applied. Lumbar MR, MRM, and myelographic findings were checked and evaluated by four independent radiologists, respectively. Each radiologist was asked to score (1 to 5) the degree of disc protrusion and nerve root compression using modified grading systems devised by the North American Spine Society and Pfirrmann and the physical examination rules for conscription in the Republic of Korea. Correlated coefficients between clinical and radiological factors were calculated. Interpretational reproducibility between MRI and myelography by four bases were calculated and compared.
Mean patient age was 20.5 ± 1.1. Mean VAS-LBP and VAS-LP were 6.7 ± 1.6 and 7.4 ± 1.7, respectively. Mean ODI was 48.0 ± 16.2%. Mean MRI, MRM, and myelography scores were 3.3 ± 0.9, 3.5 ± 1.0, and 3.9 ± 1.1, respectively. All scores of diagnostic performances were significantly correlated (p < 0.05). However, none of these scores reflected the severity of patients' symptoms. There was no statistical difference of interpretational reproducibility between MRI and myelography.
Although MRI and myelography are based on different principles, they produce similar interpretational reproducibility in young soldiers with a HLD. However, these modalities do not reflect the severity of symptoms.
Comparison study; Herniated Lumbar Disc; Interpretational reproducibility; Magnetic Resonance Imaging; MR Myelography; Myelography
We report the case of a 74-year-old woman who presented with acute-onset right groin pain irradiating to the thigh anteriorly after having suffered for a few weeks from slight knee pain. As a CT scan showed multiple herniated intervertebral discs and spinal stenosis at the L3–L4 level, she was referred to a neurosurgical unit with the tentative diagnosis of L2-L3 radicular pain. Investigations (MR, myelography with CT scan) showed severe acquired lumbar canal stenosis. Decompression surgery was finally postponed because of the patient's serious cardiac medical history and she was referred to us for conservative treatment. She was found to have iliopsoas bursitis with chondrocalcinosis of the knee. Local steroid injections of the two sites abolished her symptoms. We draw attention to the possible pitfalls that the radiographic appearance and one of the multiple clinical presentations of this unrare pathology may represent. Whenever a patient comes walking with crutches, avoids puting weight on his or her leg, and radicular pain is suspected, we advise consideration of other extra-spinal causes for the pain.
Iliopectineal bursitis; Chondrocalcinosis; Pseudogout; Calcium pyrophosphate dihydrate; Spinal stenosis
Myodil (iophendylate), an oil-based positive contrast media, now discontinued, was widely used for performing myelography 30–70 years ago. We identified this agent as the explanation for uncommon magnetic resonance imaging (MRI) findings in a patient with thoracic spinal fracture.
Case report and literature review.
An 81-year-old man complained of back pain after falling down stairs. Anamnesis revealed that he had undergone myelography with an oil-based contrast agent about 60 years previously as a part of the diagnostic workup for back pain and sudden onset of gait difficulty. Plain radiography of the thoraco-lumbar spine showed a fracture of the eleventh thoracic vertebra and a radio-opaque, oval shadow at the level of the T9–T10 vertebrae. Many small radio-opaque dots with the appearance of a string of pearls were seen from T8 to L3 vertebrae. MRI revealed a sharply demarcated intradural extramedullary mass, of approximately 5 mm in diameter on the left side of the dura in the region of the T9–T10. The mass showed high signal intensity on T1-weighted MRI, and low signal intensity on T2-weighted MRI.
Increased awareness of this rare presentation of procedures performed in the past is essential when atypical radiographic images are encountered. This case illustrates rare sequelae of Myodil use manifesting decades after administration.
Vertebral fracture; Contract media; Arachnoiditis; Myodil (iophendylate); Neuroimaging; Spinal mass; Myelography; Ventriculography; Cisternography; Axial computed tomography; Magnetic resonance imaging
Aim: To compare the diagnostic accuracy of low-dose computed tomography (CT), magnetic resonance imaging (MRI) and fluoroscopy in percutaneous discography in patients scheduled for lumbar spondylodesis. Material and methods: Within a prospective pilot study, 18 disc segments of 11 patients with radicular or pseudoradicular pain prior to anteroposterior spondylodesis were evaluated. After injection of a mixture of non-ionic iodine-containing contrast agent and gadolinium-based contrast medium into the disc spaces, all patients underwent conventional fluoroscopy, as well as low-dose CT and MRI. The occurrence of memory pain during contrast injection was recorded. CT, MRI and fluoroscopic images were analyzed independently by two readers blinded to the clinical findings. Results: There was 100% agreement between CT and MRI discography in the detection, localization and grading of degenerative changes. In contrast, conventional fluoroscopy identified only 9 of the 12 abnormal segments. Memory pain following puncture was identified in 3 of the 12 affected segments. Summary: Low-dose CT and MRI discography have a similar accuracy in the assessment of disc disruption and they are superior to fluoroscopic discography.
Computed tomography; Low dose; Magnetic resonance imaging; Discography
A herniated intervertebral disc is the most common type of soft tissue mass lesion within the lumbar spinal canal. Magnetic resonance imaging (MRI) is a useful tool for the assessment of patients with lower back pain and radiating pain, especially intervertebral disc herniation. MRI findings of intervertebral disc herniation are typical. However, from time to time, despite an apparently classic history and typical MRI findings suggestive of disc herniation, surgical exploration fails to reveal any lesion of an intervertebral disc. Our patient underwent lumbar disc surgery with the preoperative diagnosis of lumbar disc herniation; however, nothing could be found during the surgical procedure, except a swollen nerve root.
herniated intervertebral disc; magnetic resonance imaging; nerve root
A comparison of MRI and computed tomography-myelography (CTM) for lumbar intracanalar dimensions. To compare the capability and reproducibility of MRI and CTM in measuring the cross-sectional morphology of intracanalar lesions of the lumbar spine.
Materials and Methods
MRI and CTM of lumbar disc levels from 61 subjects with various lumbar spinal diseases were studied. Dural area, dural anteroposterior (AP) diameter, dural right-left diameter, and thickness of the ligamentum flavum were measured by two orthopedic surgeons. Each section was graded by degree of stenosis. Absolute value and intra- and inter-observer correlation coefficients (ICC) of these measurements and the associations between MRI and CTM values were determined.
Except for MRI determination of ligament flavum thickness, CTM and MRI and intra- and ICC suggested sufficient reproducibility. When measurements of dural area, dural AP diameter, and RL diameter were compared, values in CTM were significantly (p = 0.01-0.004) larger than those in MRI (CTM/MRI ratios, 119%, 111%, and 105%, respectively). As spinal stenosis became more severe, discrepancies between CTM and MRI in measurements of the dural sac became larger.
Both CTM and MRI provided reproducible measurements of lumbar intracanalar dimensions. However, flavum thickness may be more accurately measured by CTM. Because the differences in the measurements between CTM and MRI are very slight and there is very little data to suggest that the precise degree of stenosis is related to symptoms or treatment outcome, the usefulness of the CTM over MRI needs to be confirmed in future studies.
Magnetic resonance imaging; computed tomography; myelography; CTM; lumbar spine; lumbar spinal canal stenosis; diagnosis
A consecutive series of 397 myelograms performed in 385 patients over a six month period at the Mersey Regional Neurosciences Unit is reported. The reasons for performing the myelogram were to identify the cause of a radicular lesion in 54% of patients, a chronic spinal cord lesion in 30%, an acute cord lesion in 9%, suspected disease at the level of the foramen magnum 6%, and for a variety of other conditions in 8%. For the 385 patients undergoing a myelogram in the study period, the median interval from admission to request, request to myelography and from myelography to discharge was nought, one and three days respectively. The proportion of patients submitted to myelography by individual consultants ranged from 7% to 28%. There was a two-fold variation in the delays in the time to requesting and performing myelograms. There was room for improvement in the clinical information supplied on the myelography request form. The role of ancillary investigations and their effect on myelography was unclear. Only 16 of the patients with suspected cord disease had visual evoked responses performed before myelography. Five of them had myelography after an abnormal result. The estimated annual direct cost of myelography in the unit was at least 486,000 pounds. Reorganisation might have yielded hypothetical "savings" of between 30,000 pounds (6%) and 155,000 pounds (32%), though in practical terms these "savings" represented resources which might have been freed for use in other higher priority clinical problems within the unit, rather than true reductions in monetary cost.
The dermatomal somatosensory evoked potential from the lumbo-sacral dermatomes was recorded from 21 patients with radiographically and surgically (20) proven lumbo-sacral root compression due to prolapsed intervertebral disc or canal stenosis. The potential was abnormal in 19 of the 20 surgically proven cases. The dermatomal somatosensory evoked potential is as accurate as myelography for diagnosis but has the advantage of being non-invasive and repeatable. It provides useful additional diagnostic and pathophysiological information about lumbo-sacral root compression.
Retrospective review of imaging data from a clinical trial.
To compare the interpretation of lumbar spine magnetic resonance imaging (MRIs) by clinical spine specialists and radiologists in patients with lumbar disc herniation.
Summary of Background Data
MRI is the imaging modality of choice for evaluation of the lumbar spine in patients with suspected lumbar disc herniation. Guidelines provide standardization of terms to more consistently describe disc herniation. The extent to which these guidelines are being followed in clinical practice is unknown.
We abstracted data from radiology reports from patients with lumbar intervertebral disc herniation enrolled in the Spine Patient Outcomes Research Trial. We evaluated the frequency with which morphology (e.g., protrusions, extrusions, or sequestrations) was reported as per guidelines and when present we compared the morphology ratings to those of clinicians who completed a structured data form as part of the trial. We assessed agreement using percent agreement and the κ statistic.
There were 396 patients with sufficient data to analyze. Excellent agreement was observed between clinician and radiologist on the presence and level of herniation (93.4%), with 3.3% showing disagreement regarding level, of which a third could be explained by the presence of a transitional vertebra. In 3.3% of the cases in which the clinician reported a herniation (protrusion, extrusion, or sequestration), the radiologist reported no herniation on the MRI.
The radiology reports did not clearly describe morphology in 42.2% of cases. In the 214 cases with clear morphologic descriptions, agreement was fair (κ = 0.24) and the disagreement was asymmetric (Bowker’s test of symmetry P < 0.0001) with clinicians more often rating more abnormal morphologic categories. Agreement on axial location of the herniation was excellent (κ = 0.81). There was disagreement between left or right side in only 3.3% of cases (κ = 0.93).
Radiology reports frequently fail to provide sufficient detail to describe disc herniation morphology. Agreement between MRI readings by clinical spine specialists and radiologists was excellent when comparing herniation vertebral level and location within level, but only fair comparing herniation morphology.
herniated disc; MRI; SPORT; reliability; imaging
Intractable pain in the neck and upper extremity is frequently radicular in character and mechanical in origin. Rupture of a cervical intervertebral disc is the most common cause.
Diagnosis and localization are more difficult in the cervical than in the lumbar region. Pantopaque myelogram should be considered only as a mean of localization. Operation should be preceded by a thorough trial of conservative treatment.
A series of 24 patients presenting with features of both cervical and lumbar spondylosis and disc disease has been studied in order to evaluate the results of surgical treatment. Myelography is essential for confirmation of multifocal lesions. In all but 4 cases beneficial results were obtained after decompression of the predominantly involved region of the spinal canal. These 4 patients were improved after both lumbar and cervical laminectomy in two stages with an interval of 3-6 months. Morbidity was insignificant.
Symptomatic intraspinal lumbar facet joint synovial cysts can be managed both conservatively and surgically. Diagnosis of the lumbar facet joint cyst is made through cross-sectional imaging of the spine, either by computerized tomography (CT) scan, myelography, or most commonly magnetic resonance imaging. Conservative treatment by facet joint injection can be performed under fluoroscopic or CT guidance, although only CT guidance provides direct visualization of the cyst confirming accurate needle placement. This case report illustrates the use of percutaneous CT-guided facet joint cyst treatment as a temporizing measure or alternative to surgical treatment in the proper clinical scenario.
CT-guided injections; lumbar facet joint cysts
Fifty-six patients who had undergone fifty-seven operations for low back and leg pain thought to be associated with a prolapsed intervertebral disc have been reviewed. Forty-two had only mild residual signs and symptoms or none at all.
The patients selected for surgery were those with intractable signs and symptoms which had not improved with conservative treatment, and some were chronic low back invalids.
Myelography is a desirable adjunct in some patients when localization or diagnosis is in doubt.
In addition to the forty-two patients who had a successful outcome, five patients were improved and five who eventually had recurrences were successful at first. The figures therefore show that some measure of relief resulted from fifty-two out of fifty-seven operations performed.
The results of operation for carefully selected patients with presumptive prolapsed lumbar intervertebral disc are good. The operation is expected to relieve leg pain but more than half the patients will continue to have some discomfort or paraesthesiae. More relief from backache occurs than might be expected in view of the pathology and nature of the surgical procedure.
Most patients can return to their former occupation even though arduous.
Those accustomed to wear low back supports for years are able to stop doing so after surgery.
A small proportion of patients with initial successful results develop recurrence of back and leg symptoms. Most subside with conservative treatment and may arise from rupture of adhesions but re-exploration is sometimes necessary.
The results after the fenestration operation were not convincingly superior to those after laminectomy. Bearing in mind that the fenestration procedure was usually done on those with clear-cut signs and positive localization, it does not appear that there is anything to be gained by doing this rather more difficult operation.
Despite potential advantages of three-dimensional fluoroscopy-based navigation, there still remain a lot of controversies about the indications of this technology, especially whether it is worthy of being used in placement of pedicle screws in lumbar spine. However, according to the inconsistent conclusions reported in the literature and our experiences, the traditional method relying on anatomical landmarks and fluoroscopic views to guide lumbar pedicle screw insertion is unable to meet the requirement of precise screw placement. Based on our observation, screw malposition seems to occur concomitant with vertebral axial rotation which is a ubiquitous phenomenon. Three-dimensional fluoroscopy-based navigation can provide the most valuable axial images in real-time, so it may be useful for placement of pedicle screws in lumbar spine. This study was intended to evaluate the effect of axial rotation of lumbar vertebrae on the accuracy of pedicle screw placement using the traditional method, as well as assess the value of three-dimensional fluoroscopy-based navigation in improving the accuracy. Sixteen lumbar simulation models at different degrees of axial rotation (0°, 5°, 10°, and 20°), with every four assigned the same degree, were equally divided into two groups (traditional method group and three-dimensional fluoroscopy-based navigation group). Random placement of pedicle screws was carried out, followed by CT scan postoperatively. Then the outer pedicle cortex contours were depicted from reconstructed sectional pedicle images using Photoshop. The accuracy of pedicle screw placement was evaluated by determining the interrelationship between screw trajectory and pedicle cortex (quality), and measuring the shortest distance from pedicle screw axis to outer cortex of the pedicle (quantity). Eighty pedicle screws were implanted, respectively, in each group. In traditional method group, statistical difference existed in the accuracy of pedicle screw placement at different axial rotational degrees (P < 0.05). With degrees increasing, the accuracy declined. The accuracy of three-dimensional fluoroscopy-based navigation group was higher than traditional method group in vertebrae with axial rotation (P < 0.01). In qualitative evaluation, the accuracy of the two methods had statistical difference when the degree was 20°, and in quantitative evaluation, statistical difference existed in 5°, 10°, and 20° of vertebral axial rotation.
Lumbar spine; Pedicle screw; Vertebral rotation; Three-dimensional fluoroscopy-based navigation; Accuracy
Diagnostic methods and biomarkers of early disc degeneration are needed as emerging treatment technologies develop (e.g., nucleus replacement, total disc arthroplasty, cell therapy, growth factor therapy) to serve as an alternative to lumbar spine fusion in treatment of low back pain. We have recently demonstrated in cadaveric human discs an MR imaging and analysis technique, spin-lock T1ρ-weighted MRI, which may provide a quantitative, objective, and non-invasive assessment of disc degeneration. The goal of the present study was to assess the feasibility of using T1ρ MRI in vivo to detect intervertebral disc degeneration. We evaluated ten asymptomatic 40–60-year-old subjects. Each subject was imaged on a 1.5 T whole-body clinical MR scanner. Mean T1ρ values from a circular region of interest in the center of the nucleus pulposus were calculated from maps generated from a series of T1ρ-weighted images. The degenerative grade of each lumbar disc was assessed from conventional T2-weighted images according to the Pfirmann classification system. The T1ρ relaxation correlated significantly with disc degeneration (r=−0.51, P<0.01) and the values were consistent with our previous cadaveric study, in which we demonstrated correlation between T1ρ and proteoglycan content. The technique allows for spatial measurements on a continuous rather than an integer-based scale, minimizes the potential for observer bias, has a greater dynamic range than T2-weighted imaging, and can be implemented on a 1.5 T clinical scanner without significant hardware modifications. Thus, there is a strong potential to use T1ρ in vivo as a non-invasive biomarker of proteoglycan loss and early disc degeneration.
Intervertebral disc degeneration; Magnetic resonance imaging (MRI); Spin lock; Nucleus pulposus; In vivo
The diagnostic utility of scalp-recorded somatosensory evoked potentials (SEP) in patients with sciatica has generally been regarded as low. The purpose of the present study was to determine the validity of sensory nerve SEP in different subgroups of sciatic patients. A total of 65 consecutive patients with sciatica showing disc pathology and/or facet joint hypertrophy on lumbar computed tomography (CT) and/or myelography were studied. Symptomatic myelographically compressed nerve roots were defined as truly compromised roots. Asymptomatic myelographically normal nerve roots were defined as truly normal roots. Bilateral sensory nerve SEP representing nerve roots L4, L5, and S1 were performed in all patients. Evaluation of SEP included the use of P1 latency inter-root comparison. The false-positive rate of SEP was low. Pathological L4, L5, and S1 SEP therefore strongly indicate true compromise of the corresponding nerve roots. The true-positive rate was higher in patients with facet joint hypertrophy with or without additional disc disease than in patients with disc pathology only, and highest if the sciatic sensory symptoms were present during the SEP registration. Diagnostic validity was not influenced by previous episodes of sciatica, the duration of the present episode, or the number of spinal levels with ipsilateral myelographically compressed nerve roots. Pathological SEP strongly indicate sensory radiculopathy in patients with sciatica. Diagnostic efficacy is higher in patients with facet joint hypertrophy than in patients with disc pathology only and highest when the sciatic symptoms are present during registration.
Evoked potentials Somatosensory Diagnostic tests Sciatica Spinal stenosis Intervertebral disc displacement
To date, there have been no prospective, objective studies comparing the accuracy of the MRI, myelo-CT and myelography. The purpose of this study is to compare the diagnostic and predictive values of MRIs, myelo-CTs, and myelographies. Myelographies with dynamic motion views, myelo-CTs, MRIs and exercise treadmill tests were performed in 35 cases. The narrowest AP diameter of the dural sac was measured by myelography. At the pathologic level, dural cross-sectional area (D-CSA) was calculated in the MRI and Myelo-CT. The time to the first symptoms (TAF) and the total ambulation time (TAT) were measured during the exercise treadmill test and used as the standard in the comparison of correlation between radiographic parameters and walking capacity. The mean D-CSA by CT was 58.3 mm2 and 47.6 mm2 by MRI. All radiographic parameters such as AP diameters and D-CSA have no correlation to TAF or TAT (p>0.05). Our data showed no statistically significant differences in the correlation of the patients' walking capacity to the severity of stenosis as assessed by myelography, myelo-CT and MRI.
Spinal stenosis; myelography; spiral computed tomography; magnetic resonance imaging; exercise test; predictive value of tests