Post-operative SPECT-CT

Post-operative SPECT-CT is a bone-activity scan fused with CT, used to investigate pain that continues or returns after spinal surgery — particularly after a fusion. Working out why pain persists after an operation is one of the harder problems in spine care, and it is made harder because metal screws and rods can degrade ordinary scans. By combining bone activity with detailed anatomy, this scan can help pinpoint where the problem lies.

After a fusion, several different problems can cause ongoing pain, and they call for different solutions: the screws or rods may have loosened, the fusion may not have fully knitted together (a pseudarthrosis), or the level next to the fusion may be taking extra strain and wearing out faster. Each of these tends to produce a distinctive pattern of increased bone activity. The scan detects that activity and the fused CT ties it to the exact hardware or bone, helping tell these possibilities apart — for instance flagging an active, non-united fusion, or an active adjacent level.

The procedure is the same as any bone SPECT-CT: a small tracer injection into a vein, a couple of hours' wait while it settles, then a painless scan while the camera rotates around the area, with the CT taken at the same visit. It involves a small amount of radiation and a longer overall appointment because of the waiting period. Tell the team about your previous surgery so the scan can be focused appropriately.

When pain persists after a fusion and ordinary scans are hard to read because of metalwork, post-operative SPECT-CT can add a decisive layer of information by showing where bone is actively reacting. This can change the working diagnosis — separating loose hardware, a failed fusion, and an adjacent-level problem — and so guide the right next step. Because a loose-looking screw is not always the source of pain, findings are always weighed by the specialist together with symptoms, examination, blood tests and other imaging rather than acted on alone.

• —Royal College of Radiologists — iRefer: Making the Best Use of Clinical Radiology
• —Royal College of Radiologists / British Nuclear Medicine Society — Guidance
• —British Association of Spine Surgeons (BASS)

This information is for general patient education and is not a substitute for an individual consultation. Always seek personalised advice from a qualified spinal specialist.