Imaging tests neurosurgeons use, explained

MRI (magnetic resonance imaging) is the workhorse of neurosurgical imaging. It shows soft tissue — brain, spinal cord, discs, nerves — in exquisite detail. Most elective neurosurgical decisions rest on an MRI.

CT (computed tomography) uses X-rays and is faster, cheaper and better for looking at bone and acute bleeding. CT is the first scan in trauma and stroke because it is available immediately.

CT and MR angiography visualise the blood vessels of the brain and neck, used to diagnose aneurysms, vascular malformations and vessel narrowing. Digital subtraction angiography (DSA) — the gold standard — involves a catheter through the groin and is done in specialised centres.

Functional MRI maps active brain areas — speech, movement, vision — before surgery near critical regions. Diffusion tensor imaging maps white matter pathways for the same purpose.

PET scans are used mainly to distinguish active tumour from post-treatment scarring, and to look for metastatic disease elsewhere. Nerve conduction studies and EMG assess how well individual nerves and muscles are working — essential for many peripheral nerve and spine cases.