Spinal Infections: Timing of MRI Findings in Dogs

Objective: To assess timing of magnetic resonance imaging (MRI) findings of spontaneous pyogenic spinal infections in dogs.

Method: This retrospective observational study included 61 dogs that underwent MRI for spinal infection (48 cases of diskospondylitis, 10 cases of paravertebral abscess or phlegmon, 3 cases of epidural abscess or phlegmon), confirmed by bacteriology, cytology or histopathology. Data collected included the site of infection, the type of lesion, the degree of neurological dysfunction, the interval between the onset of symptoms and the MRI examination, and the characteristics of vertebral bodies, intervertebral discs, dorsal arthrodial joints, the vertebral canal and paravertebral soft tissues.

Results: The frequency of spinal infections at the different sites differed significantly. The presence and type of vertebral and diskchanges associated with diskospondylitis were significantly different according to the time elapsed between the first onset of symptoms and the examination. All patients examined within 5 days from the onset of symptoms showed a reduction in thickness associated with contrast medium uptake of discs involved, as well as vertebral signal hyperintensity on T2-weighted sequences associated with areas of somatic contrast medium enhancement. The magnitude of contrast enhancement was greater in fat-suppressed sequences.
Conclusions: The MRI findings of spontaneous spinal infections are highly distinctive. Changes vary with time and MRI allows early detection, within 5 days from the onset of symptoms. In cases of suspected spinal infection, MRI must be preferred to other diagnostic procedures.