Entity Features that reduce the need for imaging Features that increase the need for imaging Best test Pathology detected
Mild head trauma No history of concerning features (next column) and normal examination Abnormal examination; headache, vomiting, age >60 years, drug or alcohol intoxication, amnesia, trauma above the clavicle, seizure, Glasgow coma score <15 at 2 hours after injury, suspected open skull fracture, signs of skull base fracture, or dangerous mechanism (eg, pedestrian struck by vehicle, assault by blunt object, passenger ejected from vehicle) Head computed tomography or magnetic resonance imaging Haemorrhage, fracture, contusion
Transient neurological episode (with symptom resolution and normal neurological examination) History suggestive of migraine, benign forms of vertigo, psychogenic spells, or cardiogenic or neurogenic syncope (eg, vasovagal) Probable seizure Head magnetic resonance imaging with gadolinium (or head computed tomography with iodinated contrast) Tumour, haemorrhage, infection, inflammation, developmental anomalies
Probable transient ischaemic attack Head magnetic resonance imaging with head and neck magnetic resonance angiography (or head computed tomography and head and neck computed tomography angiography) Vascular abnormality; residual small infarction
Headache Defined benign headache syndrome (migraine, tension, medication overuse); no history of concerning features (next column), and normal examination Focal symptoms (eg, hemiparesis); abnormal neurological examination; thunderclap, cluster-type, or undefined headache; accelerating pattern; aggravation by exertion or Valsalva; onset after age 50; non-classic visual or other aura; vomiting; systemic illness or signs Head computed tomography and computed tomography angiography Haemorrhage or aneurysm
Magnetic resonance imaging with gadolinium Infection, tumour, and other inflammatory processes
Neck and low back pain No neurological deficit, age <50, no history of systemic disease or cancer, tolerable symptoms, or duration <6 weeks Neurological deficit (weakness, sphincteric dysfunction, or saddle anaesthesia), age >50, positive history of systemic disease or cancer, intolerable symptoms, or duration >6 weeks Magnetic resonance imaging (with gadolinium if infection, inflammation, or neoplasia suspected) Compressive myelopathy from degenerative disease or tumour; infectious or inflammatory myelitis
 

A guide to imaging for common neurological problems 2010