Spondylodiscitis Magnetic resonance imaging
MRI is the diagnostic procedure of choice if spondylodiscitis is suspected 1). This provides an image of the whole length of the spinal column so that spinal infection of other sections can also be detected. This procedure also reliably detects any spread of the inflammation to the paravertebral or spinal space.
Comparison of Magnetic resonance imaging of patients diagnosed with pyogenic spondylodiscitis and tuberculous spondylodiscitis allowed identification of individual characteristics for preliminary differentiation between TB and infectious spondylodiscitis and thereby enabling proper treatment 2).
T1
73-year-old male operated on L5-S1 lumbar disc herniation. Spondylodiscitis after lumbar microdiscectomy
C-REACTIVE PROTEIN 2.15mg/dL, Erythrocyte sedimentation rate 35 mm
Signal alteration in L5 and S1 vertebral body with hypointense behavior on T1 weighted image sequence
STIR
Hyperintense on STIR attributable to edema, with enhancement of the vertebral bodies as well as perivertebral soft tissues. The intervertebral disc L5-S1 presents an increase in its signal in STIR in its middle and posterior third that continues with an abscess in the left paracentral operated extruded disc area that presents peripheral enhancement and that obliterates the left recess and displaces the thecal sac , with approximate measurements of 23 mm x 22 mm (axial x cc), contacting the ipsilateral S1 root. Peri and paravertebral inflammatory changes in the left anterior and posterior epidural space, as well as in the surgical path of the left laminectomy. The findings are compatible with spondylodiscitis L5-S1 with a disc abscess in its middle-posterior third that presents an extrusion to the left recess. Signs of degeneration and dehydration of the L3-L4 discs with loss of disc space height, marginal osteophytes and Modic type II changes in the adjacent plates, without significant canal stenosis.
- MRI: gadolinium enhancement of adjacent vertebral bone marrow, as well as enhancement of the disk space and posterior annulus fibrosis;
decreased T1 disk uptake and increase disk uptake on T2 images
http://img.medscapestatic.com/pi/meds/ckb/50/15350tn.jpg
Diskitis/osteomyelitis is seen on this T2-weighted MRI of the lumbar spine, which demonstrates destruction of the L3-4 disk space with the adjacent endplate and/or vertebral body. L3 and L4 vertebral bodies show increased T2 signal, indicating edema and/or infarction. Also shown is a retropulsion of debris, which compresses the thecal sac.
The MRI will reveal air changes in the disc and possibly even external involvement involving the bone or epidural regions. A biopsy may be performed and helps with diagnosis in some cases but often an organism is not obtained.