What is the role of MRI in the diagnosis of Pott disease (tuberculous [TB] spondylitis)?

Updated: Aug 08, 2019
  • Author: Jose A Hidalgo, MD; Chief Editor: John L Brusch, MD, FACP  more...
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Answer

Magnetic resonance imaging (MRI) is the criterion standard for evaluating disk-space infection and osteomyelitis of the spine and is most effective for demonstrating the extension of disease into soft tissues and the spread of tuberculous debris under the anterior and posterior longitudinal ligaments. [37] MRI is also the most effective imaging study for demonstrating neural compression. [38, 39]

Contrast-enhanced MRI findings are useful in differentiating tuberculous spondylitis from pyogenic spondylitis. MRI findings in Pott disease include thin and smooth enhancement of the abscess wall and a well-defined paraspinal abnormal signal. Thick and irregular enhancement of the abscess wall and an ill-defined paraspinal abnormal signal suggest pyogenic spondylitis. [40] The images below are studies of a man aged 31 years with spinal tuberculosis.

Involvement of the disk is typically a characteristic of infectious spondylitis; however, this may not always be the case, and Pott disease can present with atypical features resembling neoplastic lesions. Findings of an intradural extramedullary mass at the lower end of the spinal cord associated with holocord T2 hyperintensities of the choroid has been described in intramedullary tubercular abscesses ”precipitation sign." [41, 42, 43, 44]

Three MRI parameters have been found to be strongly suggestive of spinal tuberculosis: subligamentous spread of abscess, vertebral body collapse, and large abscess collection with thin abscess wall. A combination of these MRI findings has a higher predictive value, an odds ratio of 16.3 when comparing a group of patients with spinal tuberculosis versus a group of patients evaluated for spondylodiscitis with a different diagnosis. [45]

MRI of a 31-year-old man with tuberculosis of the MRI of a 31-year-old man with tuberculosis of the spine. Images show the thoracic spine before and after an infusion of intravenous gadolinium contrast. The abscess and subsequent destruction of the T11-T12 disc interspace is marked with arrowheads. Vertebral body alignment is normal. Courtesy of Mark C. Diamond, MD, and J. Antonio Bouffard, MD, Detroit, Mich.
MRI of the T11 in a 31-year-old man with tuberculo MRI of the T11 in a 31-year-old man with tuberculosis of the spine. Extensive bone destruction consistent with tuberculous osteomyelitis is evident. The spinal cord has normal caliber and signal. No evidence of spinal cord compression or significant spinal stenosis is distinguishable. Courtesy of Mark C. Diamond, MD, and J. Antonio Bouffard, MD, Detroit, Mich.

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