Spinal neuropathic arthropathy, also known as Charcot spine, can destroy the intervertebral disk space, adjoining vertebral bodies and facet joints. Although not a very common problem, it can resemble spinal infection, metastatic disease, or other degenerative diseases.
Researchers from Thomas Jefferson University in Philadelphia and Wilford Hall Medical Center at the Lackland Air Force Base in Texas turned to computed radiography, CT and MRI to draw up a list of imaging criteria that could differentiate between the processes. They reviewed the films for 33 patients who were treated either for Charcot spine or disk space infection between 1993 and 1998 (Radiology, March 2000, Vol. 214 (3), pp. 693-699).
The 14 patients with neuropathic arthropathy were followed up clinically for six months after imaging by a neurosurgeon and one of the study’s authors. During this time, no patient developed disk space infection. Of the 14, one dozen had conventional radiographs taken, seven had CT scans and MRI was done in six cases.
For the 19 patients with disk space infection, images were obtained with conventional radiography in 13 cases, CT scans were done in nine and 12 patients underwent MRI. All images were examined for the presence of endplate sclerosis, endplate erosions, osteophytes, decreased disk height, spondylolisthesis, facet involvement, vacuum disk phenomenon, paraspinal soft-tissue mass, disorganization and debris.
The protocol and general results were as follows:
- Conventional radiographs were obtained with standard projections of anterior-posterior, lateral, right and left posterior oblique and lateral spot image. According to the study, facet involvement, vacuum disk, debris and disorganization were seen more frequently in patients with Charcot spine than those with disk space infection.
- CT studies were obtained by using 3 x 3-mm transverse sections, a 130-150 mm scanning field and sagittal reconstruction. The authors reported that similar frequencies of endplate sclerosis, endplate erosions, osteophytes and paraspinal soft-tissue mass were present in both groups of patients, although disk bulge was more common in patients with spinal neuropathic arthropathy, as was debris and disorganization.
- Finally, MR images were take with a 1.5-tesla unit. T1-weighted and T2-weighted, spin echo images were obtained in the sagittal and transverse planes. In five patients with Charcot spine and 11 with disk space infection, gadolinium-enhanced MR images were taken as well. The best discriminators on MR images were facet involvement, vertebral body spondylolisthesis, disorganization and debris. No distinguishing signal intensity characteristics were noted in the disks of either group.
The group concluded that facet involvement and vacuum disk were more common in patients with Charcot spine than in those with infection. Other traits of spinal neuropathic arthropathy include osseous joint debris and joint disorganization. In the end, the authors did not recommend one modality over another, but asserted that their findings did not agree with earlier studies that touted T1 and T2-weighted MR imaging.
"Endplate erosion, endplate sclerosis, osteophyte formation, loss of disk height, paraspinal soft-tissue mass, and signal intensity characteristics on T1 and T2-weighted MR images were not useful .… The reported observation that T2-weighted MR images can help differentiate spinal neuropathic arthropathy from disk space infection was not supported by our results," they said.
To view the article in full, visit http://radiology.rsnajnls.org/cgi/content/full/214/3/693
