A. Head

The Head (section 1)

Clinical Issue		Modality	Recommended?		Comment
Congenital disorders (For children see section 13)	101	MRI	Indicated	[B]	Definitive exam for all malformations. CT may be needed to define bone and skull base anomalies. Sedation or GA may be required for infants and young children. *(for congenital disorders in children see 1301 and 1302)*
Acute Stroke (See also N01, N02)	102	CT	Indicated	Diagnosis [A] Treatment [B]	A policy of CT for most strokes as soon as reasonably possible is to be encouraged, but at least within 48 hours, as this will ensure accurate diagnosis of the cause, site and appropriate primary treatment and secondary prevention.
		MRI	Specialised investigation	[B]	MRI should be considered in young patients with stroke, in patients presenting late where it is essential to know whether they have previously had a haemorrhage, and in suspected posterior fossa stroke in patients whom it is important to demonstrate the site of the stroke lesion.
		US carotids	indicated only in specific circumstances	[B]	Should only be performed in: (1) those with full recovery in whom carotid endarterectomy is contemplated for secondary prevention; (2) suspected dissection; or (3) young patients, whether disabling or non-disabling ischaemic stroke.
Transient ischaemic attack (TIA) *(See also 205)*	103	CT	Indicated	[B]	May be normal. Can detect established infarction and haemorrhage and exclude disease processes that can mimic stroke syndromes, such as glioma, extra cerebral haemorrhage and cerebritis.
Transient ischaemic attack (TIA) *(See also 205)*	103	US carotids	Indicated	[B]	To assess suitability for carotid endarterectomy or angioplasty. Angiography, MRA and CTA are alternatives to show the vessels. MRI and NM can be used to show function.
Demyelinating and other white matter disease	104	MRI	Indicated	[A]	MRI is viewed as the most sensitive and specific investigation for establishing a diagnosis of multiple sclerosis. The diagnosis is made by demonstrating dissemination of clinical events and lesions in space and time.
?Space occupying lesion (SOL)	105	MRI	Indicated	[B]	MRI is most sensitive for early tumours, in resolving exact position (useful for surgery) & for posterior fossa lesions. MRI may miss calcification.
?Space occupying lesion (SOL)	105	CT	Indicated	[B]	CT often sufficient in supratentorial lesions.
Headache: acute, severe ; subarachnoid Haemhorrage	106	CT	Indicated	[B]	The clinical history is critical. A clinician should be able to diagnose patients who have classical migraine or cluster headaches without CT. SAH headache comes on typically in seconds, rarely in miniutes and almost never over more than 5 miniutes. CT will provide evidence of haemhorrage in up to 98% of patients with SAH is performed on a modern scanner within the first 48 hours of ictus. An LP should still be performed on all patients (delayed 12 hours after ictus for xanthochromia) with suspected SAH but with negative CT. CT is indicated in patients with acute onset headache with focal neurological signs, nausea or vomiting, or GCS below 14. An LP is the diagnostic test of choice for meningitis unless there are focal signs or a significantly depressed level of consciousness.
Headache: acute, severe ; subarachnoid Haemhorrage	106	MRI or NM	Specialised investigation	[C]	MRI better than CT for inflammatory causes. SPECT may be the most sensitive investigation for encephalitis and can provide evidence of circulatory derangement in migraine.
Headache:chronic *(For Children see Section 13)*	107	CT/MRI	Indicated only in specific circumstances	[C]	In the abscence of focal features imaging is not usually useful. The following features significantly increase the odds of finding a major abnormality on CT or MRI: recent onset and rapidally increasing frequency and severity of headache headache causing wake from sleep associated dizziness, lack of coordination, tinging or numbness (for headache in children see M08)
Headache:chronic *(For Children see Section 13)*	107	XR Skull, Sinus, C Spine,	Indicated only in specific circumstances	[B]	Radiography of little use in the absence of focal signs/symptoms.
Pituitary & juxta-sellar problems	108	MRI	Specialised investigation	[B]	Urgent referral when vision is deteriorating
Pituitary & juxta-sellar problems	108	SXR	Not indicated	[C]	Patients who require investigation need MRI or CT.
Posterior fossa signs	109	MRI	Indicated	[A]	MRI is the investigation of choice. CT images often degraded by beam hardening artefacts.
Hydrocephalus ?shunt function *(For Children see Section 13)*	110	CT	Indicated	[B]	CT adequate for most cases; MRI sometimes necessary and may be more appropriate in children. US first choice for infants. (for hydrocephalus in children see M06)
	110	XR	Indicated	[C]	If there is evidence of hydrocephalus on CT, XR can demonstrate the entire valve system
Middle or inner ear symptoms (including vertigo)	111	CT	Specialised investigation	[B]	Evaluation of these symptoms requires ENT, neurological or neurosurgical expertise.
Sensorineural hearing loss (For Children see Section 13)	112	MRI	Specialised investigation	[B]	MRI much better than CT, especially for acoustic neuromas. (For deafness in children see M05.)
Sinus disease *(For Children see Section 13)*	113	Sinus XR	Indicated only in specific circumstances	[B]	Acute sinusitis can be diagnosed and treates clinically. If it persists past 10 days on appropraite treatment, XR sinus may be required. Signs on XR sinus are often non-specific and encountered in asymptomatic individuals. (for sinus disease in children see M09)
Sinus disease *(For Children see Section 13)*	113	CT	Specialised investigation	[B]	CT is useful to demonstrate the presence and distribution of disease and sinonasal anatomy. Low-dose technique is desirable. CT is indicated when maximal medical treatment has failed, when complications arise (such as orbital cellulitis) or if malignancy is suspected.
Dementia & memory disorders, first onset psychosis	114	SXR	Not indicated	[A]	SXR should only ever be used to show clinically relevant abnormalities of the skull bones.
		CT	Indicated only in specific circumstances	[A]	Yield is low, even in younger patietns; neurological signs and rapid progression increase it. Over the age of 65, CT can be reserved for patients with an onset within the last year or an atypical presentation, rapid unexplained deterioration, unexplained focal neurological signs or symptoms, a recent head injury (preceding the onset of dementia) or urinary incontinence and/or gait ataxia early in illness
		MRI or NM	Not Indicated	[B]	More sophisticated examinations (MRI, SPECT) have no proven clinical value, although they may be used in research.
Orbital lesions	115	CT	Specialised investigation	[A]	CT remains the investigation of choice. MRI may be of value if CT is unhelpful or gives insufficient detail. Consider US for intraocular lesions.
Orbital lesions	115	MRI	Not Indicated	[A]	Suspected orbital lesions require specialist referral
Orbital lesions : trauma	116	CT	Specialised Investigation	[A]	Ct is indicated when orbital trauma may be combined with major facial fracture. If a less severe blow-out fracture is suspected, CT is carried out only if the patient is a candidate for surgery.
Orbital lesions : suspected foreign body	117	CT	Specialised Investigation	[A]	Indicated when XR fails to show a strongly suspected foreign body which may not be metallic, when multiple foreign bodies are present, or when it is not certain whether a previously demonstrated foreign body is intra-occular
		XR Orbits	Indicated	[A]	A single 'soft' lateral XR is the only projection required to exclude a metallic foreign body; eye-moving images are required only for confirmation of the intraocular position of a foreign body once demonstrated. Prior to an MRI study a posteroanterior XR is adequate to exclude a significant metallic foreign body. If a foreign body is confirmed CT may be required by some specialists.
		US	indicated	[B]	Us may be indicated for radiolucent foreign bodies or where XR is difficult
Acute visual loss: Visual disturbances	118	SXR	Not indicated	[A]	Specialists can diagnose many cases without resorting to imaging
		MRI/CT	Specialised Investigation	[A]	MRI is preferable for suspected lesions of the optic chiasm. Ct is preferable for orbital lesions
		Cerebral Angiography	Specialised Investigation	[A]	Specialist referral is indicated
Epilepsy (adult) *(For Children see Section 13)*	119	MRI	Specialised Investigation	[B]	Structural imaging is the technique of choice. Higher soft-tissue resolution and multiplanar capability give greater sensitivity and specificity for the identification of small cortical lesions. Particularly valuable in the evaluation of partial epilepsy, e.g. temporal lobe epilepsy.
		CT	Specialised investigation	[B]	Following trauma, CT may complement MRI in the characterisation of lesions, e.g. calcification
		NM	Specialised Investigation	[B]	Ictal SPECT or interictal PET is useful in the planning of epilepsy surgery when MRI is negative or its results conflict with EEG or neurophysiological evidence. Regional cerebral blood flow (rCBF) agents are also of value

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