Suspected intracranial haemorrhage (non-traumatic)

ACR AC Cerebrovascular Diseases (2024); ACR AC Aneurysm/VM/SAH (2021)

Unenhanced CT is definitive for acute blood and needs nothing added to it. The vetting value lies downstream: deciding which patients need angiography for an underlying vascular cause, and which need delayed MRI for an underlying lesion.

Acute deficit, reduced consciousness or severe headache, frequently in a patient on an anticoagulant, where the immediate question is whether there is blood and whether reversal is needed now.

Referenced decision support — confirm against your local protocol.

Decision support, not a directive. Protocols and timings shown are typical published ones — your local protocol takes precedence, and the vetting radiologist decides.

The request in front of you

Everything is optional. Leave a field alone and the answer assumes nothing — the verdict updates as you go.

Study requested

What the referrer actually asked for. It is evidence of intent, not a constraint on the right answer.

Contrast as written

What the request form says, not what it should say.

Age

Pick a band, or type an exact age if it matters.

years

Pregnancy status

Haemodynamic state

The fact that lets a pathway waive its own requirements. A crashing patient does not wait for a score.

GCS

Anticoagulated or on antiplatelets

Moves the threshold for imaging head injury further than any other single item of history.

Renal risk factors

The question a vetter can actually answer from the request. An explicit “none known” is a real answer, and it removes checks rather than deferring them.

Previous contrast reaction

The pathway — tap anything already done

Marking a study complete moves the answer on. A patient arrives partway through a pathway far more often than at the start of one.

Accept as requested

CT Head — Unenhanced

CT Head

What we'd amend, and why

Acute extravascular blood is dense on CT without any contrast, which makes the unenhanced study both the most sensitive and the fastest test for this question. Adding contrast at this stage actively harms interpretation, because enhancing vessels and dense blood become difficult to separate. The result also drives an immediate action — anticoagulation reversal, blood pressure control, neurosurgical referral — so speed is part of the diagnostic value.

Nothing needs resolving before this goes ahead. Routine checks below are owned downstream.

How was this decided?

pathwayadult — Adults
rulerule-paeds-dose — Child-sized technique and contrast dose; checked by Radiographer at the scanner

Decision support only. Local protocol takes precedence.

Handled at the scanner(1)nothing for you to do

Settled and owned downstream. Each returns to a radiologist only on the stated trigger.

Child-sized technique and contrast dose
Confirm that a size- or weight-based protocol is selected — child-sized kV and mAs against size-based diagnostic reference ranges — and that contrast volume is calculated by weight rather than taken from an adult default. Weight-based iodinated contrast volumes of roughly 1.5–2.0 mL/kg are widely used in paediatric CT.
Radiographer at the scannerAt the scanner
Flags back if: No paediatric or size-based protocol exists on the scanner for the requested examination, or the requested coverage or number of phases exceeds what the clinical question needs — for example a multiphase study where a single phase answers it, or whole-body coverage for a focal question.

Pathways

Big forks are separate pathways; the first whose conditions match is the one used.

On an anticoagulant, a depressed conscious level, or haemodynamically unstable — scan and communicate immediately

Role	Study & protocol	Why this answers the question
First line	CT Head CT Head — Unenhanced usually appropriate	The study does not change and the timescale does. Three things follow a positive scan in this patient within minutes rather than hours — reversal of the anticoagulant, blood pressure control, and a neurosurgical conversation about a patient who is no longer protecting their airway — and haematoma expansion in the first hours is both commoner and larger on anticoagulation, so the volume at presentation is not the volume that matters. Report it live to the referring team rather than into a queue. A patient at a Glasgow Coma Scale of 8 or less is intubated and resuscitated on the way to the scanner, not held anywhere for it. Haemodynamic instability here is not blood loss — this bleed is inside a closed box and does not empty the circulation — so read it as one of two things, both of which the scan answers: a hypertensive emergency, where the pressure is driving the expansion and the confirmed diagnosis is what licenses lowering it, or the bradycardic hypertensive Cushing response of a brain that is coning, where the destination after the scanner is theatre or a neurosurgical unit rather than a ward bed. Neither is a reason to stabilise first and image later; the scan is the thing that tells the team which one they are treating, so it belongs on the resuscitation-room scanner with the team present.
Second line	CT Angiogram — Intracranial (Circle of Willis) CT Angiogram — Intracranial Arteries	The underlying-cause question is unchanged by anticoagulation, and it is worth saying so explicitly: an anticoagulant is an explanation for bleeding more than a cause of it, and in a young or normotensive patient with lobar or subarachnoid-predominant blood the aneurysm or malformation still has to be excluded. Acquired early, the spot sign it may show predicts the expansion this group is most at risk of.
Problem solving	MRI Brain MRI Brain — with gadolinium	Delayed rather than acute, exactly as on the main pathway: once the blood products have evolved, gadolinium-enhanced MRI is what shows an underlying tumour, cavernoma or venous infarct, and susceptibility imaging maps the microbleed burden that separates hypertensive from amyloid-related disease — the latter being the finding that changes whether anticoagulation is restarted at all.

Adults

Matches your inputsDefault

Role	Study & protocol	Why this answers the question
First line	CT Head CT Head — Unenhanced usually appropriate	Acute extravascular blood is dense on CT without any contrast, which makes the unenhanced study both the most sensitive and the fastest test for this question. Adding contrast at this stage actively harms interpretation, because enhancing vessels and dense blood become difficult to separate. The result also drives an immediate action — anticoagulation reversal, blood pressure control, neurosurgical referral — so speed is part of the diagnostic value.
Second line	CT Angiogram — Intracranial (Circle of Willis) CT Angiogram — Intracranial Arteries	Once blood is confirmed, angiography asks whether an aneurysm, arteriovenous malformation or dural fistula caused it. The yield is concentrated in young patients, lobar or subarachnoid-predominant blood, and haemorrhage without a hypertensive explanation. Acquired early it also demonstrates active extravasation within the clot, which predicts expansion.
Problem solving	MRI Brain MRI Brain — with gadolinium	A haemorrhage can hide the lesion that caused it. Delayed MRI with gadolinium, performed once the acute blood products have evolved, is the test for an underlying tumour, cavernoma or venous infarct, and susceptibility imaging additionally maps the microbleed burden that distinguishes hypertensive from amyloid-related disease. Done too early it is frequently uninterpretable, which is why the timing matters as much as the sequences.

Pitfalls

Requesting contrast on the initial study. Enhancement mimics and masks acute blood, and the unenhanced scan already answers the question.
Stopping at the unenhanced CT in a young or normotensive patient with lobar haemorrhage — the underlying vascular cause is the finding that changes management.
Arranging MRI in the first days for the underlying lesion. Acute blood products obscure enhancement; a delayed study is far more informative.
Assuming a small volume of blood is benign. Expansion in the first hours is common, particularly on anticoagulants, and the volume at presentation is not the volume that matters.

Priors — what to pull first

Compare with any prior study for pre-existing infarct, atrophy or microbleeds before attributing findings to the acute event.
A recent scan in an anticoagulated patient with a fall makes interval growth the question rather than presence or absence.

What makes a good request

The pattern of blood, not the fact of it, drives the follow-on. Deep basal ganglia haemorrhage in a hypertensive patient rarely needs vascular imaging; lobar, intraventricular or subarachnoid-predominant blood in a young or normotensive patient usually does.
State the anticoagulant and the last dose on the request. It does not change the study, but it changes how urgently the result must be communicated.

Scoring this once it is done

The classification and risk tools this question ends in.

ICH Score Intracerebral Hemorrhage Volume (ABC/2)Spetzler-Martin AVM Grade

How these studies are acquired

Contrast, phases and timing for every study on the pathways above.

CT Head — Unenhanced CT Angiogram — Intracranial Arteries MRI Brain — with gadolinium

Confirm locally

CT Head — Unenhanced: timings are typical — confirm against local protocol.
Timings, contrast volumes and rates above are typical published values. Your department's protocol, scanner and patient population decide the actual numbers.
Safety thresholds and premedication policy follow local policy where it differs from the cited guidance.

References

Implemented from the cited published sources. Educational and workflow support only; confirm against current guidelines and local policy before clinical use.