Aneurysm DSA

Subarachnoid Hemorrhage - Sentinel Bleed.

Axial Non contrast CT shows a focal hyper dense subarachnoid blood in left parietal cortical sulcus.
Sentinel bleed is a warning bleed due to minor blood leakage, precedes aneurysm rupture by a few hours to a few months, present with sudden focal or generalized headache, should not be overlooked must be screened on time to rule out underlying aneurysm with non invasive MR Angio or DSA.
Subarachnoid Hemorrhage – Massive and diffuse.

Axial Non contrast CT shows diffuse sub arachnoid bleed in basal cistern, interhemispheric fissure and sylvian fissure.

Most common causes of spontaneous SAH are rupture of a saccular (berry) aneurysm (80%) and rupture of an arteriovenous malformation (AVM) (10%). Causes of non aneurysmal SAH include amyloid angiopathy, blood dyscrasias, fibromuscular dysplasia, Moyamoya disease, vasculitis (10%)
As per the Law of La Place, the tension on the wall is proportional to the diameter. Thus, the rate of rupture is directly related to the size of the aneurysm.
Aneurysms usually occur at arterial bifurcations and mostly arise from the anterior circulation of the Circle of Willis (85%).

Left ACA Aneurysm

ACom Aneurysm

Basilar tip Aneurysm

MCA bifurcation Aneurysm

ICA Tip Aneurysm

Pcom Aneurysm

ICA bifurcation aneurysm

CT and MRI Brain with MR Angio

Non contrast CT Brain

MRI Brain Axial FLAIR

MR Angio Non contrast 3 D TOF

This non contrast CT study of brain shows hyper dense subarachnoid bleed in basal cisterns, sylvian fissures and bilateral hemispheric cortical sulci which is hyper intense on axial FLAIR Brain.
An associated mild to moderate hydrocephalus.
Non contrast 3 D TOF MR Angiogram of brain shows an Aneurysmal out pouching from right ICA at its bifurcation.

Internal carotid artery (ICA) bifurcation aneurysms are uncommon, little is known about its incidence, anatomical characteristics and results of endovascular treatment.
Equally distributed to the right and left side. When present on either side called Mirror aneurysms.

Intracranial hemorrhage

An intracranial hemorrhage is bleeding within the skull.
Occurs when a blood vessel within the skull is ruptured or leaks.
Can result from trauma as in head injury or non traumatic causes like hemorrhagic stroke secondary to hypertension, ruptured aneurysm, anticoagulant therapy or blood clotting disorders.
Itself a serious medical emergency as it can lead to raised intracranial pressure due to its mass effect and perilesional odema or can limit the blood supply of normal brain tissue. Internal herniations can lead to compression of vital brain structures.

Imaging modality:
CT scan ideal initial tool as it is definitive, accurate diagnosis, mass effect, cost effective, less time consuming for emergencies, suitable for non cooperative patients, easy availability, familiarity to new doctors on call,
MRI with Angiography for better evaluation in cases of non hypertensive haemorrhage to rule out underlying vascular malformation.

Broad classification: Intra-axial and Extra-axial.
Intra-axial haemorrhage: bleeding within the brain.
1. Intraparenchymal hemorrhage : bleeding within the brain parenchyma.
2. Intraventricular hemorrhage : bleeding within the brain's ventricles.

1. Intraparenchymal bleed further classified as basal ganglioinic and lobar bleed. Basal ganglionic are more common than lobar bleed, usually hypertensive. Lobar bleed are less likely to be hypertensive and other causes needs to ruled out.

2. Intraventricular hemorrhage are usually associated with or secondary to intra parenchymal bleed. Isolated intra ventricular bleed are rare.

Intra-axial haemorrhages are more dangerous and difficult to treat than Extra axial and are associated with further complications.

Extra-axial hemorrhage : bleeding that occurs within the skull but outside of the brain tissue.
1. Epidural hematoma : Between the skull and the dura.
2. Subdural hematoma : Between the dura and the arachnoid.
3. Subarachnoid hemorrhage: Between arachnoid and Pia.


Epidural hematoma (EPH)
98% cases associated with fracture; Post traumatic.
Involved vessel in tempero parietal region (Most common location) is Middle meningeal artery, In frontal region is anterior ethmoidal artery, in occipital region is transverse or sigmoid sinuses, in Vertex locus is superior sagittal sinus.
Lucid interval followed by unconsciousness.
Shape of collection is Biconvex or lentiform.
Surface area of hematoma smaller compared to sub dural, since limited by dural attachment at sutures.
Never cross suture lines.
May cross mid line falx in frontal region as its is outside the dura.


Sub dural hematoma (SDH)                            
Traumatic as well as non traumatic.
Involved vessels bridging veins.
Gradually increasing headache and confusion.
Shape of collection is concave or Crescent-shaped.
Surface area of hematoma larger , extend antero posteriorly over cerebral convexity.
Crosses suture line but never cross mid line.
May extend along interhemispheric fissure and tentorium.

Subarachnoid hemorrhage (SAH)

Besides from head injury may occur spontaneously, usually from a ruptured cerebral aneurysm.
Symptoms of SAH include a severe headache with a rapid onset ("thunderclap headache"), vomiting, confusion or a lowered level of consciousness, sometimes seizures.
CT is initial modality of choice seen a hyper density in the region of cortical sulci, basal cistern and sylvian fissure depending upon amount of bleed.
If CT is normal to be followed with MRI FLAIR and MR Angiography.
Confirmation is by lumbar puncture.