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ALL YOU NEED TO KNOW ABOUT STROKES AND CT HEAD INTERPRETATION MRama Aubeeluckeen Reviewed by Dr Rajiv Ark Here’s what we do: ■ Weekly tutorials open to all! ■ Focussed on core presentations and teaching diagnostic technique If you’re new here… ■ Bstudentsl students, for medical ■ Reviewed by doctors to ensure W elcome to accuracy T eaching ■ We’ll keep you updated about our Things! upcoming events via email and groupchats!https://app.medall.org/c/teaching-thingsStrokes Mohammed BinyameenContents - Stroke Vs TIA - Presentation + RFs - Function and blood supply of the brain, brainstem + cerebellum - Different types of stroke based on location - Treatment - Other differentials to considerPoll - How much neurology has everyone covered?SBA A 68-year-old man presents with sudden-onset right-sided weakness and slurred speech that resolved completely within 30 minutes. CT head is unremarkable. What is the most appropriate diagnosis? ● A) Ischemic stroke ● B) Transient ischemic attack (TIA) ● C) Hemorrhagic stroke ● D) Seizure with Todd’s paresis ● E) Migraine with auraSBAS A 68-year-old man presents with sudden-onset right-sided weakness and slurred speech that resolved completely within 30 minutes. CT head is unremarkable. What is the most appropriate diagnosis? ● A) Ischemic stroke ● B) Transient ischemic attack (TIA) ● C) Hemorrhagic stroke ● D) Seizure with Todd’s paresis ● E) Migraine with aura Answer: B) Transient ischemic attack (TIA)Stroke Vs T ransient Ischaemic Attack Lack of blood flow = ischaemia Stroke types: - Haemorrhage (15%) - SAH / / Thrombus Prolonged ischaemia = Necrosis + infarction Intracerebral haemorrhage Stroke - Ischaemia with infarction TIA - Ischaemia without infarctionPresentation Features: - Unilateral weakness/sensory loss - Aphasia/Dysarthria - Vertigo/Ataxia - Visual problems - Swallowing problems Assessment tools: - FAST - ROSIERRisk factors RFs for ischaemic stroke: RFs for haemorrhagic stroke: - Age - Age - Hypertension - Hypertension - Smoking - AVMs - Hyperlipidaemia - Anticoagulation - Diabetes - Underlying conditions (ADPKD) - Atrial fibrillation - Think all the general CVD risk factorsFunction of different lobes Lobe Major functions Frontal Behaviour, Executive function, Movement Parietal Sensation, Vision, Reading, Language Temporal Vision, Speech, Memory, Hearing Occipital VisionBlood supply of the brain Blood supply for cerebral cortex: - Internal carotid artery -> Anterior cerebral + Middle cerebral - Vertebral artery -> Basilar artery -> Posterior cerebralHomunculus of the PMC In an ACA stroke the leg weakness would be more pronounced than in a MCA strokeStroke symptoms by artery ACA: Lacunar strokes: - Contralateral leg weakness/sensory loss - Pure motor loss - Pure sensory loss MCA: - Ataxic hemiparesis - Contralateral arm + face weakness/sensory loss - Aphasia (dominant, usually LHS) - Hemispatial neglect (non-dominant) - Contralateral homonymous hemianopia PCA: - Contralateral homonymous hemianopia with macular sparing - Visual processing difficulties (e.g. agnosia) Learn the Bamford/Oxford stroke classificationHomonymous hemianopia with Homonymous hemianopia without macular sparing macular sparingSBA A 60-year-old man presents with sudden-onset weakness predominantly in his right leg and mild slowness of speech. He denies facial weakness or significant arm involvement. Examination reveals increased tone and brisk reflexes in the right lower limb. Which artery is most likely affected? ● A) Middle cerebral artery ● B) Anterior cerebral artery ● C) Posterior cerebral artery ● D) Basilar artery ● E) Vertebral arterySBA A 60-year-old man presents with sudden-onset weakness predominantly in his right leg and mild slowness of speech. He denies facial weakness or significant arm involvement. Examination reveals increased tone and brisk reflexes in the right lower limb. Which artery is most likely affected? ● A) Middle cerebral artery ● B) Anterior cerebral artery ● C) Posterior cerebral artery ● D) Basilar artery ● E) Vertebral artery Answer: B) Anterior cerebral arteryBrainstem anatomy + Blood supplyCranial nerve recap Not going to go through these but will leave it here as it'll help with the next partBrainstem strokes Weber’s syndrome (blockage of the PCA that supplies the midbrain): - Ipsilateral CNIII palsy (dilated, down + out pupil, ptosis) - Contralateral weakness of upper and lower limbs Lateral pontine syndrome (blockage of the AICA): - Facial nerve palsy + hearing loss (CN 5 and 8) - Ataxia + nystagmus (cerebellar damage) - CL body and IL face anaesthesia (spinothalamic damage) - IL Horner’s (sympathetic damage) Lateral medullary/Wallenberg syndrome (blockage of the PICA): - Dysphagia (CN 9/10) - Ataxia + nystagmus (cerebellar damage) - CL body and IL face anaesthesia (spinothalamic damage) - IL Horner’s (sympathetic damage)SBA A 55-year-old man presents with sudden onset of right-sided weakness and diplopia. Examination reveals right-sided hemiparesis and left-sided ptosis, with the eye deviated down and out. Which artery is most likely affected? ● A) Posterior cerebral artery ● B) Middle cerebral artery ● C) Basilar artery ● D) Superior cerebellar artery ● E) Anterior inferior cerebellar arterySBA A 55-year-old man presents with sudden onset of right-sided weakness and diplopia. Examination reveals right-sided hemiparesis and left-sided ptosis, with the eye deviated down and out. Which artery is most likely affected? ● A) Posterior cerebral artery ● B) Middle cerebral artery ● C) Basilar artery ● D) Superior cerebellar artery ● E) Anterior inferior cerebellar artery Answer: A) Posterior cerebral arteryCerebellar strokes Think DANISH - Dysdiadochokinesia - Ataxia - Nystagmus - Intention tremor - Scanning speech (Slow speech) - HypotoniaAphasias Broca’s aphasia (MCA) - Preserved comprehension but cannot articulate the words. Wernicke’s aphasia (MCA) - Fluent language with nonsensical speech Conduction aphasia - Normal fluency and comprehension. Cannot repeat things backInvestigation and managementIs it a haemorrhage or ischaemia? First line Ix = Non-contrast CT head. Covered in more detail laterManagement of TIA - Refer to stroke specialist - 24 hour referral if TIA within last 7 days. 7 day referral otherwise - Antiplatelets - Aspirin 300mg immediately followed by 75mg OD for 21 days. Clopidogrel started by specialist (300mg loading dose followed by 75mg OD indefinitely) - Control CVD RFs - Check BP, lipids, HbA1c and provide diet/exercise advice - Imaging - May be done by stroke specialist (usually MRI). May also docarotid US if required. Consider CT head if patient is on anticoagulantsT reatment for ischaemic stroke Initial management: - ABCDE - Make sure they are stable and not hypoxic - Maintain normal blood glucose, oxygen, temperature, hydration, etc. - Screen for unsafe swallow - Blood pressure - Do not aim for normotensive (CPP = MAP - ICP). Should be less than 185/110 - CT head within 1 hour Ischaemic stroke specific management - depends on time of presentation: - If within 4.5 hours can offer thrombolysis AND thrombectomy - If between 4.5 and 24 hours can offer thrombectomy alone if potential to salvage brain tissue - If presented after 24 hours offer just antiplatelets Antiplatelets - Aspirin 300mg for 14 days followed by Clopidogrel 75mg indefinitelyThrombolysis vs thrombectomy Alteplase = Tissue plasminogen activator. Plasmin causes breakdown of clot by degrading fibrinSBA A 70-year-old woman presents to the Emergency Department with sudden-onset right-sided weakness and slurred speech. Symptoms began 2 hours ago. CT head shows no evidence of hemorrhage and she is clinically stable. She has been given 300mg Aspirin in the community. What is the most appropriate next step in management? ● A) IV thrombolysis with alteplase ● B) IV thrombolysis with alteplase and mechanical thrombectomy ● C) Mechanical thrombectomy ● D) Clopidogrel 75 mg orally ● E) IV mannitolSBA A 70-year-old woman presents to the Emergency Department with sudden-onset right-sided weakness and slurred speech. Symptoms began 2 hours ago. CT head shows no evidence of hemorrhage and she is clinically stable. She has been given 300mg Aspirin in the community. What is the most appropriate next step in management? ● A) IV thrombolysis with alteplase ● B) IV thrombolysis with alteplase and mechanical thrombectomy ● C) Mechanical thrombectomy ● D) Clopidogrel 75 mg orally ● E) IV mannitol Answer: B) IV thrombolysis with alteplase and mechanical thrombectomyT reatment of haemorrhagic stroke Initial management = Same as before Haemorrhagic stroke specific management: - Urgent neurosurgical referral - Reversal of any anticoagulation - Lower BP to below 140 systolicOther differentials to think of Transient ischaemic attack - Resolves usually within an hour Todd's paresis - Preceding seizure + Resolves within a few hours Migraine with aura - Usually resolve completely + Previous history of migraines Bell’s palsy - No forehead sparing + Sx confined to one side of face Multiple sclerosis - Symptoms disseminated in time and space + Younger patient + History of optic neuritis Neuropathies - Follows distribution of peripheral nerve + Lack of central symptoms such as dysphagia Imaging interpretation Rama AubeeluckHow confident are you about interpreting neurological imaging? ● Practically a neuroradiologist ● I can do spot diagnosestructure but I’m unsure on a few things ● I know nothing ● I am not sureRapid fire spot diagnosis!Spot diagnosis 1 1. Subdural haematoma 2. Brain cancer 3. HSV encephalitis 4. Extradural haematoma 5. Multiple sclerosisSpot diagnosis 1 1. Subdural haematoma 2. Brain cancer 3. HSV encephalitis 4. Extradural haematoma 5. Multiple sclerosis ● Right sided ● Biconvex (bulging outwards) ● Limited by suture linesSpot diagnosis 2 1. HSV encephalitis 2. Brain cancer: gliobastoma multiforme 3. Subdural haematoma 4. Brain cancer: meningioma 5. Multiple sclerosisSpot diagnosis 2 1. HSV encephalitis 2. Brain cancer: gliobastoma multiforme 3. Subdural haematoma 4. Brain cancer: meningioma 5. Multiple sclerosis ● Left sided ● In fronto temporal region ● Surrounding oedemaSpot diagnosis 3 1. Multiple sclerosis 2. Chronic subdural haematoma 3. HSV encephalitis 4. Acute subdural haematoma 5. Brain cancer: meningiomaSpot diagnosis 3 1. Multiple sclerosis 2. Chronic subdural haematoma 3. HSV encephalitis 4. Acute subdural haematoma 5. Brain cancer: meningioma ● Left sided ● Hyperdense crescent shaped bleed ● Not limited by suture linesSpot diagnosis 4 1. Multiple sclerosis 2. Subarachnoid haemorrage 3. Meningioma (brain cancer) 4. HSV encephalitis 5. Chronic subdural haematomaSpot diagnosis 4 1. Multiple sclerosis 2. Subarachnoid haemorrage 3. Meningioma (brain cancer) 4. HSV encephalitis 5. Chronic subdural haematoma ● Hyperattenuation of supracellar and sylvian cisterns ● Not the starfish signSpot diagnosis 5 1. Motor neurone disease 2. Acute subdural haematoma 3. Guillan-Barre syndrome 4. Multiple sclerosis 5. Chronic subdural haematomaSpot diagnosis 5 1. Motor neurone disease 2. Acute subdural haematoma 3. Guillan-Barre syndrome 4. Multiple sclerosis 5. Chronic subdural haematoma ● Left sided ● Hypodense crescent shaped bleed ● Not limited by suture linesSpot diagnosis 6 (MRI) 1. Chronic subdural haematoma 2. HSV encephalitis 3. Temporal arteritis 4. Broca’s aphasia 5. Motor neurone diseaseSpot diagnosis 6 (MRI) 1. Chronic subdural haematoma 2. HSV encephalitis 3. Temporal arteritis 4. Broca’s aphasia 5. Motor neurone disease ● Right sided frontotemporal discharges ● Concurrent with HSV encephalitis if presentHow does a CT scan work? Any ideas?CT scan: how it works? ● CT = Computed tomography ● Tomography = Imaging technique allowing you to take cross-sectional images (slices) of the body ● CT head = Imaging technique using multiple X-rays to take multiple images of the head ● Hounsfield Units: Some tissues allow X-rays to pass through them (lots of penetration), whereas others have a poor penetration - so X-rays cannot pass through them ● The brightness in an X-ray or CT image depends on how many X-rays hit the detector!● Denser materials e.g. bone absorb MORE x-rays, so LESS x-rays pass to the detector ● Imaging software assigns high absorption to bright pixels ● The detector "sees" less signal in those regions -> a brighter appearanceAnatomy basicsAnatomy basics: the skullAnatomy basics: middle meningeal artery ● Branch of the maxillary artery ● dura materion is to supply the ● Passes behind the pterion bone, which is relatively thin, and is more likely to be fractured in traumatic injuries ● This can lead to extradural haematomasAnatomy basics: layers of the scalpAnatomy basics: dural layersAnatomy basics: bridging veins ● Bridge the subarachnoid space to the dura mater ● Help cool the brain and form an alternative drainage route of the brain in the case of obstruction of dural venous sinuses ● Rupture of these causes subdural haematomasAnatomy basics: the subarachnoid space ● The arachnoid granulations /villi are outpouchings of the arachnoid mater ● These go into the subarachnoid ● CSF is drained here and goes into the venous systemAnatomy basics: brain lobes and thalamusAnatomy basics: ventricle system ● Produce CSF ● 4 ventricles: right and left lateral ventricles (counts as 2), third ventricle and fourth ventricle ● Lateral: have horns which project into the frontal, occipital and temporal lobes. Most visible on a CT headAnatomy basics: ventricle system ● Third: Connects to lateral via foramen of Monro. Situated in between the right and the left thalamus ● Fourth: Connects to 3rd via cerebral aqueduct, and lies within the brainstem. Drains into the spinal cord and subarachnoid cisterns (where it is reabsorbed into the circulation)Anatomy basics - putting it togetherCT head interpretation Why is a structured approach important? First step: confirm patient details, compare to any previous images Call out any obvious diagnosis you can see Mnemonic - Blood Can Be Very Bad ● Blood: bleeding ● Can: cisterns ● Be: brain ● Very: ventricles ● Bad: boneBlood - 4 main bleeds to think about On a CT head, bleeding appears as areas of increased density (hyperattenuation) compared to the surrounding brain tissue due to the higher concentration of hemoglobin in blood. ● Acute bleeding (within hours): Appears bright white because fresh blood has a high Hounsfield Unit (HU). ● Chronic bleeding (after days to weeks): Becomes darker (hypodense) as the blood is broken down and reabsorbed, blending with the surrounding brain tissue.What are some symptoms of raised intracranial pressure? List in the chat !Symptoms of raised intracranial pressure Common to anything increasing pressure in the brain: bleeding, infection causing inflammation, tumours, hydrocephalus etc. ● Cushing's response (decreased HR , increased BP) ● Headache (worse on coughing, leaning forwards), vomiting ● Altered GCS: drowsiness, listlessness, irritability, coma ● Pupil constriction then dilation ● Decreased visual acuityExtradural haematoma ● Between the dura mater and the skull ● Dura is tightly adhered to the inner surface of the skull, and this attachment is particularly strong at the suture lines. ● Blood in this space cannot cross suture lines because the dura is fixed at these boundaries ● The haematoma therefore takes on a lens-shaped or biconvex appearance on imaging ● Extra-axial (outside the brain)Blood - extradural haematoma ● Cause: trauma - affects the middle meningial artery ● Pathophysiology: blood collects between the skull and dura (“extra-axial”) ● Clinical features: patient initially loses, briefly regains (lucid interval) and then loses again consciousness after a low-impact head injury. Plus general raised ICP symptoms ● CT head findings: biconvex (or lentiform), hyperdense collection around the surface of the brain, limited by the suture lines of the skull ● Definitive management: craniotomy and evacuation of the haematomaSubdural haematoma ● Between the dura mater and the arachnoid mater ● These layers are continuous across the skull, so blood can spread freely over the brain's surface, crossing suture lines. ● Extra-axialBlood - subdural haematoma ● Cause: Low impact head injury ● Pathophysiology: blood collects between the dura and arachnoid layer - can be chronic (hypoattenuated)) or acute (hyperattenuated) ● Risk factors: Old age and alcohol make the bridging veins weaker ● Clinical features: Fluctuating level of consciousness (seen in 35%) ± insidious physical or intellectual slowing, sleepiness, headache, personality change, and unsteadiness. Plus general raised ICP symptoms. ● CT head findings: Hyper/hypo dense crescentic collection, not limited by suture lines. Large bleeds can shift the brain and cause midline shift or herniation. ● Definitive management: If severe, craniotomy or burr hole washoutBlood - subarachnoid haemorrhage Acute blood (hyperdense/bright on CT) is typically distributed in the basal cisterns, sulci and in severe cases the ventricular system Blood - subarachnoid haemorrhage ● Cause: Traumatic injury most common cause. If no trauma, consider spontaneous SAH, where berry aneurysms are the most common cause (think ADPKD, Ehlers-Danlos, coaraction of the aorta) ● Pathophysiology: Bleeding in to the subarachnoid space, where CSF is located, between the pia mater and the arachnoid membrane ● Clinical features: Thunderclap headache at the back of the head, meningism, N/V ● CT Head findings: Acute blood (hyperdense/bright on CT) is typically distributed in the basal cisterns, sulci and in severe cases the ventricular system. Negative in 7% case. ● Definitive management: Treat underlying cause e.g. if aneurysm suspected, consider clipping or coiling ● Complications: Re-bleeding, vasospasm (ischaemia), hyponatraemia, seizures Blood Other places of bleeding can be intracerebral (within the brain tissue - left image), and intraventricular (within the ventricles themselves)Blood Strokes ● Hypodensity (darker) ● Loss of grey white differentiationCisterns Anatomy basics ● Recall from earlier the subarachnoid space (between the arachnoid layer and the pia) ● Cisterns refer to any of the openings in the subarachnoid space of the brain filled with CSF ● CSF is made in the choiroid plexus in the ventricles (lateral, third, fourth) ● CSF flows through the ventricles, and passes into the subarachnoid space through different apertures ● This allows CSF to enter the different cisterns within the subarachnoid spaceCisterns Cisterns Key cisterns to assess for effacement, blood and asymmetry: ● Ambient: surrounding the midbrain ● Suprasellar: superior to the sella turcica (where the pituitary gland sits) ● Sylvian: across the insular surface and within the Sylvian fissure (lateral side) ● corpora quadrigeminal: adjacent to the By examining these cisterns on a CT head, you can detect signs of subarachnoid haemorrhage, mass effect, or hydrocephalus.Brain - any pathologies in the brain tissue itself? Things to look out for ● Midline shift - has the brain been pushed toward one side? ● Sulcal effacement (thinning) ● Grey-white matter differentiation: poor differentiation suggests hypoxia, infarction, tumours or abscesses ● Any abnormal shifts in the brain tissue ● Masses - suggestive of tumours ● Hypodense foci: less dense, so think air (pneumocephalus) or fluid (oedema) ● Hyperdense foci: more dense, so thinkBrain - midline shift ● Subdural haematoma ● sidees the brain to the leftBrain - sulcal effacement Not a diagnosis in itself Causes: ● Oedema ● Space occupying lesions ● Hydrocephalus ● Bleeds ● InfectionsHow do I comment on a mass / bleed / pathology? Think about ● What side is the pathology on? ● Is there a specific anatomical landmark the pathology is predominantly covering e.g. a lobe or ventricle? ● Is the pathology hyperdense or hypodense? E.g. for the glioblastoma multiforme “I can see a mass in the left hemisphere, predominantly in the front-temporal region. There is an area of hypeodensity glioblastoma multiforme”.e of oedema. These findings are suggestive of aBrain - tumours Meningioma has oedema around itrme - classicallyWhat is the most common cause of brain cancer? 1. Glioblastoma multiforme 3. Metastases 4. Vestibular Schwannoma 5. Pilocytic astrocytomaWhat is the most common cause of brain cancer? 1. Glioblastoma multiforme - most common primary tumour in adults 3. Metastases - most common overallprimary tumour in adults 4. Vestibular Schwannoma 5. Pilocytic astrocytoma - most common primary tumour in childrenBrain - tumours form of brain cancerost common MeningiomaVentricles - normally the lateral componentVentricles Pathologies to look out for ● Bleeds ● Hydrocephalus: excess CSF in the ventricular wall space - normal pressure, obstructive, non-obstructive ● Calcification: The choroid plexus produces CSF and exists within all ventricles - this can become calcified in older individuals and is normal - do not mistake this for a bleed!Ventricles ● Clear hyperattenuation in ● More so on the left sideVentricles Normal pressure hydrocephalus ● Cause: secondary to reduced absorption at arachnoid villi ● Clinical features: incontinence, confusion, and gait disturbance (“wet, wacky, wobbly” ● CT head findings: Hydrocephalus with ventriculomegaly in the absence of, or out of proportion to, sulcal enlargement ● Management: VP shuntingVentriclesBone Can you identify any bony abnormalities? In a medical school exam this is unlikely to be a pathology they’d test you on: “I cannot see any bony pathologies”Category Condition Imaging findings Bleeds/Stroke Extradural haematoma (CT) Biconvex / lens-shaped hyperdensity; does not cross sutures. May have midline shifting List of conditions Subdural haematoma (CT) Crescent-shaped hyperdensity; can cross sutures. May have midline shifting to learn Subarachnoid haemorrhage Hyperdensity in the basal cisterns, Sylvian (CT) fissures, or sulci Intracerebral haemorrhage Localised hyperdensity within the brain (CT) parenchyma Ischaemic stroke (CT) Loss of grey-white differentiation, hypodensity in vascular territory Intracranial venous Dense dural sinus (clot), empty delta sign thrombosis (MRI) Infections HSV encephalitis (MRI) Hyperintensity in the fronto-temporal lobes Cancer Glioblastoma multiforme Irregular rim-enhancing lesion with (MRI) surrounding oedema Meningioma (CT/MRI) Extra-axial, well-defined, enhancing lesion; often with dural tail Metastases (MRI) Multiple enhancing lesions with oedema Ventricles Hydrocephalus (CT) Enlarged ventricles; possible periventricular hypodensity (CSF leakage) Autoimmune Multiple sclerosis (MRI) Hyperintense white matter plaques, often periventricular (Dawson’s fingers)T est yourself! Leandro Trossard, a 44 year old male, presents with a severe headache. He has a PMH of ADPKD. In 5 minutes, please: ● Present this CT head ● Give your most likely diagnosis ● Propose a management plan for this patient Example answer This is a non-contrast CT head for a 54-year-old male presenting with a sudden onset severe headache Bleeding: There is diffuse subarachnoid haemorrhage (SAH) visualised in the basal cisterns, bilateral Sylvian fissures, and inter-hemispheric fissure. Cisterns: All basal cisterns are hyperdense due to the presence of blood. Brain: There is no evidence of midline shift, infarction, or mass effect. No focal parenchymal abnormalities. Ventricles: The ventricular system appears normal in size, with no signs of hydrocephalus or calcification Bone: No bony abnormalities identified. The most likely diagnosis given the findings suggest a diffuse subarachnoid haemorrhage likely due to a ruptured intracranial aneurysm given the medical history of ADPKD Management Plan 1. Stabilise: A2E approach, monitor and control BP to prevent rebleeding 2. Neurological Support: Admit to a high-dependency unit (HDU) or intensive care unit (ICU), monitor for signs of raised intracranial pressure (ICP) and neurological deterioration. 3. Imaging and Intervention: Urgent CT angiogram to identify bleeding source, discuss with neurosurgery for considerationof surgical clipping or coiling. 4. Complication Prevention: Administer nimodipine to reduce the risk of vasospasm, monitor for and manage complications such as seizures, hydrocephalus, and rebleeding. Resources I found helpful 1. https://geekymedics.com/ct-hea d-interpretation/ 2. Radiopaedia for understanding pathologies 3. Running through OSCE cases where I have to present a CT head THANKS FOR W ATCHING! Please fill out the feedback form on Medall and see you next week!References