The validity of upright myelography for diagnosing lumbar disc herniation

Successful visualization of dynamic change of lumbar nerve root compression with the patient in both upright and prone positions using dynamic digital tomosynthesis-radiculography in patients with lumbar foraminal stenosis: An initial report of three cases

The symptoms of lumbar foraminal stenosis are often exacerbated when the patient is upright. Lumbar pathological conditions related to clinical symptoms such as disc herniation, foraminal stenosis, and instability of the lumbar spine are often exacerbated when the patient is upright and hidden when the patient is supine. Lumbar radiculopathy is usually diagnosed by MRI. However, it is difficult to detect the compression of nerve roots while the patient is upright using conventional MRI when the patient is supine. Dynamic digital tomosynthesis radiculography (DTRG) while the patient is upright detects pathological changes of the lumbar nerve root while the patient is upright. We report cases of symptomatic lumbar foraminal stenosis which were diagnosed by using digital tomosynthesis radiculography with the patient in an upright position. Three patients with history of unilateral leg pain which was exacerbated when they were upright underwent selective nerve root block and DTRG in both prone and upright positions. All patients were relieved of the leg pain after selective nerve root block. DTRG with the patient in an upright position showed better exacerbation of nerve root compression than while the patient was prone in all cases. DTRG with the patient in prone and upright positions is useful to detect compression of nerve roots hidden while MRI is conducted with the patient supine. DTRG is helpful to diagnose lumbar foraminal stenosis which is exacerbated while the patient is upright.

Imaging intervertebral disc degeneration

Magnetic resonance imaging provides excellent anatomic detail of spinal tissues, but fails to provide the type of information that permits a definitive diagnosis in many patients with back pain. New imaging strategies that can be applied to the study of intervertebral disc degeneration include diffusion-weighted imaging, magnetic resonance imaging, diffusion tensor imaging, magnetic resonance spectroscopy, functional magnetic resonance imaging, dynamic computed tomography and magnetic resonance imaging, and T2 relaxometry. With dynamic imaging, the relative motions of normal and degenerated lumbar motion segments can be evaluated noninvasively. With further evaluation of the technique, hypermobile segments may be distinguishable from those with normal relative motion. T2 measurements obtained by T2 relaxometry appear to have important advantages with regard to spinal imaging because this modality provides a continuous and objective measure of the content of free water in the disc, which decreases with aging and degeneration. Anatomic imaging of the spine is highly accurate in the evaluation of nonmechanical causes of back pain and less beneficial in the evaluation of back pain that is due to mechanical causes. The development of functional imaging strategies of the spine will likely improve the management of patients with back pain. This article outlines the current magnetic resonance imaging protocols for intervertebral disc degeneration, indicates deficiencies in current imaging, and describes functional imaging strategies for the spine that will likely improve the evaluation of patients with back pain. It also reviews recent published articles on magnetic resonance imaging and computed tomographic imaging of the spine and details the results of studies that have explored the future potential of spine imaging.

False Negative Magnetic Resonance Imaging Results: A Report of 2 Cases

OBJECTIVES

The purpose of this study is to present 2 clinical case studies in which large herniated disks were not detected on magnetic resonance imaging (MRI), leading to false negative results, and discuss some issues regarding potential shortcomings of MRI.

CLINICAL FEATURES

Cases of cervical and lumbar herniated nucleus pulposus (HNP) are presented. Each patient had severe pain and neurological deficit. The patients had positive physical examination findings suggestive of HNP despite the negative MRI scans. Both subsequently underwent myelography and computed tomography to arrive at the final and definitive diagnosis of HNP.

INTERVENTION AND OUTCOME

Both patients failed a course of conservative care that included manual and mechanical traction, manual mobilization, myofascial release techniques, epidural steroid injections, oral steroid and narcotic medications, and rehabilitative exercises. Both patients eventually required surgical decompression.

CONCLUSION

False negative MRI results in these cases of large HNPs emphasize the importance of case history and physical examination findings as the basis for ordering diagnostic tests. The conclusion of this article is simple; no single diagnostic test should be considered as 100% accurate, as false negative studies may occur that may mislead the patient and clinician.

Medical imaging of intervertebral disc degeneration: current status of imaging

STUDY DESIGN

The author reviewed literature and reports on spine imaging, selected key articles in which novel imaging strategies were described, and prepared a review of currently developing imaging strategies in intervertebral disc degeneration.

OBJECTIVES

To provide a review of imaging in intervertebral disc degeneration that covers the current methodology briefly and describes developing techniques in detail.

SUMMARY OF BACKGROUND DATA

Computed tomography and magnetic resonance imaging provide excellent anatomic images of the spine. However, anatomic imaging of the spine does not reliably identify the source of pain in patients with intervertebral disc degeneration. Many functional imaging techniques are suited to the study of the spine. Some of these techniques will improve our understanding of intervertebral disc degeneration and clinical symptomatology.

METHODS

The author selected reports in the current literature for further review and attempted to describe succinctly the material in the reports that are most relevant to spine imaging.

RESULTS

New and potentially useful imaging strategies for spine imaging include dynamic computed tomography, dynamic magnetic resonance imaging, functional magnetic resonance imaging, diffusion imaging, and magnetic resonance spectroscopy.

CONCLUSIONS

Technological advances in magnetic resonance imaging and computed tomography imaging continue to offer more opportunities to investigate and diagnose back pain and intervertebral disc degeneration.

Computed tomography of the normal lumbosacral intervertebral disc in 22 dogs

Computed tomography of the lumbosacral spine was performed on 22 purpose-bred, medium-sized hound dogs between 1 and 6 years of age. Images were evaluated to determine the degree of disc bulge. All dogs were neurologically normal. Dogs were imaged in dorsal recumbency with the pelvic limbs variably extended. Sagittal reconstructions were made from transverse images. The mean (+/-SD) width of the mid-portion of the L7-S1 intervertebral disc was 0.5 +/- 0.07 cm (range 0.33-0.62 cm). All L7-S1 intervertebral discs were dorsally convex, with the mean bulge measuring 0.25 +/- 0.07 cm (range 0.17-0.50 cm). The height of the vertebral canal at L7-S1 was 0.91 +/- 0.11 cm (range 0.68-1.15 cm). The mean percentage of the vertebral canal occupied by the bulge was 26.89 +/- 5.05% (range 20.74-43.08%). Mild bulging of the L7-S1 intervertebral disc can be present without associated neuropathy in medium-sized dogs.