Which imaging studies are recommended for patients with low back pain, and when should they be ordered?

For patients with low back pain, imaging studies are generally not routinely recommended in a non-specialist setting ³. This applies to low back pain with or without sciatica ³. Patients should be informed that if they are referred for a specialist opinion, imaging may still not be necessary ³.

Imaging should only be considered in specialist settings of care, such as a musculoskeletal interface clinic or hospital, and only if the results are likely to change the patient's management ³.

Imaging is indicated when there are 'red flag' symptoms or signs suggesting a potentially serious underlying cause, or if another underlying cause for symptoms is suspected ¹,². These serious causes include conditions like cancer, infection, trauma, or inflammatory diseases such as spondyloarthritis ³. In such cases, emergency hospital admission or specialist referral may be arranged, with urgency depending on clinical judgment ¹,².

Specific imaging recommendations and timings for suspected serious conditions include:

• Suspected Metastatic Spinal Cord Compression (MSCC): An MRI scan should be performed as soon as possible, and always within 24 hours, at a local hospital or appropriate centre with direct access to imaging facilities ⁴.
• Suspected Spinal Metastases (without MSCC): An MRI scan should be offered within 1 week at the local hospital to guide treatment options ⁴.
• MRI Scan Details: MRI of the spine should include sagittal T1 and/or short TI inversion recovery (STIR) sequences of the whole spine, sagittal T2-weighted sequences, and supplementary axial imaging through any significant abnormality ⁴.
• CT Scan Alternative: If MRI is contraindicated for suspected spinal metastases or MSCC, a CT scan should be carried out ⁴. Plain X-rays of the spine are not recommended to diagnose or rule out spinal metastases or MSCC ⁴.
• Suspected Spinal Injury (Adults 16 or over): CT is performed if imaging for cervical spine injury is indicated by the Canadian C-spine rule, or if there is a strong suspicion of thoracic or lumbosacral spine injury associated with abnormal neurological signs or symptoms ⁵. If a neurological abnormality attributable to spinal cord injury is present, an MRI should be performed after the CT, regardless of CT findings ⁵.
• Suspected Thoracic or Lumbosacral Column Injury (Children and Adults): An X-ray is the first-line investigation for suspected spinal column injury without abnormal neurological signs or symptoms in the thoracic or lumbosacral regions (T1–L3) ⁵. A CT scan should be performed if the X-ray is abnormal or if clinical signs or symptoms of a spinal column injury are present ⁵.