Guidelines for Follow-Up CT Scans in Spondylodiscitis

Initial Diagnostic Approach

MRI with and without contrast is the primary diagnostic modality for spinal infections, with 96% sensitivity, 94% specificity, and 92% accuracy, and should include T1, T2 with fat suppression or STIR sequences, followed by T1 sequences with contrast in axial and sagittal planes 1
[18F]FDG PET/CT could be the preferred modality for detection of spondylodiscitis within 14 days of symptom onset, and is recommended in patients with spinal hardware, preferably performed 3-4 months after surgery 2, 3

CT provides valuable information on endplate irregularities, erosions, destruction, and extension to adjacent soft tissues, and is particularly useful in pre-surgical planning and follow-up of instrumented spine 1, 2, 4
When spinal fracture is suspected and conventional radiography is negative, CT should be performed 5
CT findings supportive of infection include endplate irregularities, erosions, destruction, and presence of collections, though these may be absent early in the disease 2, 4

Clinical and laboratory parameters (ESR and CRP) should be the primary means of monitoring treatment response 1

Delaying treatment while waiting for imaging studies if neurological deficits are present 1
Using CT as the primary diagnostic tool for epidural abscess due to its low sensitivity (6%) 1

Approximately 10% of cases may have non-contiguous multilevel infections, which should be considered in the diagnostic workup 2, 7
In cases of diagnostic uncertainty, PET-CT with FDG may be useful, especially if MRI is inconclusive or contraindicated 1
[18F]FDG PET/CT has been shown to change management in 52% of patients with spondylodiscitis 2