MRI Findings in Spinal Tuberculosis (TB)

MRI is the imaging modality of choice for diagnosing spinal tuberculosis, with a sensitivity of 96%, specificity of 94%, and accuracy of 92%. 1

Characteristic MRI Findings

Vertebral body destruction and erosions, particularly of the endplates, are seen in nearly all cases (159/161 vertebrae) 2
Loss of vertebral body height in approximately 58% of affected vertebrae 2
Multiple contiguous vertebral involvement is common, with an average of 3.2 vertebrae affected per patient 2
Lumbar spine is most commonly affected (43.3%), followed by thoracic spine (36.6%) 3

Intervertebral disc is partially or fully preserved in 88.2% of cases, which differs from pyogenic infections where disc destruction is more prominent 2
Discitis is present in 98% of cases 2

Paravertebral and prevertebral collections/abscesses are seen in virtually all patients 2, 4
Paravertebral abscesses are typically septated and well-defined 2
Subligamentous spread of infection is a hallmark finding (seen in 156/161 vertebrae) 2

Marrow edema is present in all affected vertebrae, appearing as low signal on T1-weighted images and high signal on T2-weighted images 2, 1
In tuberculous spondylitis, T1-weighted sequences appear more sensitive than T2-weighted sequences in demonstrating inflammatory processes in vertebral bodies 1
Exudative lesions are common (158/161 vertebrae) 2

Gadolinium enhancement increases diagnostic confidence by better characterizing and delineating the disease process 4
Enhancement helps detect reactivation in old and healed TB 4
Epidural enhancement combined with abnormal lab values is predictive of positive biopsy results for spondylodiscitis 1

Fragmentary type of bone destruction is the most frequent pattern (48.2%), followed by lytic type (24.1%) 3
Relative preservation of disc space compared to pyogenic infections 2
Subligamentous spread with extensive paraspinal abscesses 2, 4
Posterior element involvement in approximately 40% of cases 4

Destruction of 2 or more contiguous vertebrae and their opposed endplates 1
Spread along the anterior longitudinal ligament 1
Disc infection with or without a paraspinal mass or mixed soft tissue fluid collection 1
Less commonly, spondylitis without disc involvement 1

MRI findings often appear more extensive (34.7%) than appreciated on plain radiographs 2
Cord edema is observed in some cases with neural deficit 2
Canal encroachment doesn't always correlate with severity of neurological deficit 2

MRI without and with IV contrast should be the first imaging choice in patients with suspected spinal TB 1
Look for the combination of paravertebral collections, marrow edema, subligamentous extension, epidural extension, endplate erosions and discitis (present in 83% of TB spine cases) 2
If MRI cannot be performed (e.g., implantable cardiac devices, cochlear implants, claustrophobia), consider a combination spine gallium/Tc99 bone scan, CT scan, or PET scan 1
In patients with suspected TB spine, perform tuberculin skin test (PPD) or interferon-γ release assay, especially in those from endemic regions 1

TB spine can sometimes mimic malignant processes, including metastatic disease 5
Large psoas abscesses can occur without obvious signs of bone involvement 5
MRI findings often lag behind clinical improvement based on clinical and laboratory parameters 1
Diffusion-weighted imaging sequences may help differentiate infectious spondylitis from reactive (Modic type 1) vertebral endplate changes 1