Guidelines for Imaging of Neurological / Neurosurgical Disorders

Headaches

Unenhanced CT only required for new onset of headaches or significant changes in character of chronic headaches.
Especially if accompanied by other neurological symptoms, drowsiness or related to posture.

Stroke

The acute question is bleed vs infarct, for which unenhanced CT is ideal.
In the subacute/chronic setting eg TIA, carotid doppler ultrasound as well as unenhanced CT is recommended.
For possible brainstem strokes or in a young patient MRI is usually preferred.

Seizures

All patients with epilepsy should have an MRI at some stage, even if the condition has been present for years.

Trauma

Skull films are not generally indicated.
Acute loss of consciousness, subsequent drowsiness, neurological symptoms all require unenhanced CT.
Chronic post-concussion headaches/symptoms, consider unenhanced CT.
"Space Occupying Lesion"
With suggestive symptoms only (i.e. low probability) unenhanced CT.
With symptoms and signs (i.e. high probability) MRI should be obtained.
Possible metastases (known primary) is best investigated with contrast enhanced MRI.
Screening for intracranial aneurysms
Should be considered in patients with a strong family history (2 or more first degree relatives with subarachnoid haemorrhage).
Magnetic Resonance Angiography is an accurate non-invasive means of screening for this. Neurosurgical counselling is recommended prior to screening.

Spine

Trauma - plain films +/- CT if required.
Persistent pain - plain films.
Pain and radicular symptoms/sciatica - MRI preferred (CT adequate).
Spondylolysis - reversed angle CT.
Myelopathy, progressive lower limb weakness, bladder/bowel symptoms - MRI

Other

Occasionally encountered disorders for which MRI has completely replaced CT include: MS, pituitary disorders, atypical trigeminal neuralgia and sensorineural hearing loss.
In general, MRI is preferred in young children, as they often require a GA for imaging.

CT and MRI are currently available at St George's Radiology.
CT  available at Cashmere Radiology
MRI at Southern Cross and Hagley Radiology.

If you would like to discuss a case, the following Christchurch Radiology Group radiologists have subspecialty interest in neuroradiology:
Dr Scott Wells 021 946 014
Dr Ross Keenan 021 332 953
Dr David O'Neill-Kerr 021 905 053

Scott Wells
Neuroradiologist
CHRISTCHURCH RADIOLOGY GROUP