CBL Review Case 2 FERN WHITE

MRI What is the difference between T1-weighted and T2-weighted MRIs? DWI? Diffusion weighted MRI. Images the random motion of water molecules as they diffuse through the extra-cellular space. Regions of high mobility “rapid diffusion” DARK Regions of low mobility “slow diffusion” BRIGHT T1T2 Short timing between pulsesLong timing between pulses Low signal (dark) = Water; flowing Hb; fresh Hb; Haemosiderin Low signal (dark) = Bone; flowing Hb; Deoxy Hb; Haemosiderin High signal (light) = Bone; fat; cholesterol High signal (light) = Water; cholesterol; Fresh Hb Contraindications?

Carotid Doppler Carotid ultrasound uses high-frequency sound waves to create pictures of the insides of your carotid arteries (based on Doppler effect). Used to investigate whether plaque has been building up in ICA. Criteria for reading ultrasound: Normal: ICA PSV <125 cm/sec; no visible plaque. < 50 % ICA stenosis: ICA PSV <125 cm/sec; plaque or thickening is visible % ICA stenosis: ICA PSV is cm/sec and plaque is visible. >70 % ICA stenosis : ICA PSV >230 cm / sec; visible plaque and luminal narrowing (the higher the Doppler parameters lie above the threshold of 230 cm/sec, the greater the likelihood of severe disease). Near occlusion of the ICA: velocity parameters may not apply, since velocities may be high, low, or undetectable. Diagnosis is established primarily by demonstrating a markedly narrowed lumen. Total occlusion of ICA: no detectable patent lumen at gray-scale US and no flow with spectral, power, and colour Doppler US. Normal carotid artery Carotid stenosis

Define TIA. Transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischaemia, without acute infarction. Resolved within 24 hours. Define stroke. Neurological deficit of cerebrovascular cause that persists beyond 24 hours or is interrupted by death within 24 hours What is a stroke mimic? A nonvascular disease which causes stroke like symptoms examples include seizures, sepsis, space occupying lesions, migraine, toxic/metabolic disorders.

Risk factors?

Transient Ischaemic Attack Causes of TIA? o Atheroembolism from carotid o Cardioembolism – thrombus post MI or in AF, valve disease, prosthetic valve o Hyperviscosity – polycythemia, sickle cell anaemia, increased WCC Can you think of any signs of causes for TIA? Can you remember Virchow’s Triad?

Diagnosis?  Hx and examination  FBC; ESR; U&Es; Glucose; Lipids  CXR  ECG  Carotid Doppler  CT  DW MRI – any existing infarcts? Bilateral would suggest cardioembolism What is Haemorrhagic Transformation of Infarct? Why is this particularly important? Ischemic attack transforms into a haemorrhage. Occurs due to reperfusion of the infarcted area - these blood vessels have been weakened and can bleed when blood flow is restored. This is particularly important as the initial attack will be treated with anti coagulants. Stop immediately!

Common sites for strokes and associated symptoms? The 3 cerebral arteries involved in an infarct are: Middle Cerebral Artery (MCA), Anterior Cerebral Artery (ACA) and Posterior Cerebral Artery (PCA). Of these, the most common site for a stroke is the Middle cerebral artery. Location of infarctSymptoms Middle cerebral artery Superficial division: Contralateral effects. Face and arm upper-motor weakness, sensory loss if sensory cortex is involved. Right = potential nonfluent aphasia if Broca’s area affected. Lenticulostriate branches: Contralateral effects. UPM hemiparesis due to damage to basal ganglia (globus pallidus, striatum) and genu of internal capsule. Larger infarcts extending to cortex may produce deficitis such as aphasia. Anterior cerebral artery Contralateral effects. UMN weakness due to damage to motor cortex; sensory loss due to damage to sensory cortex. Right: Grasp reflex, frontal lobe behavioural abnormalities, and transcortical aphasia if prefrontal cortex and supplemental motor involved. Left: Grasp reflex, frontal lobe behavioural abnormalities and left hemineglect if prefrontal cortex and non-dominant association cortex involved. Posterior cerebral artery Contralateral effects. Homonymous hemianopia due to damage in visual cortex of occipital lobe. Larger infarcts involving the internal capsule and thalamus may cause hemisensory loss and hemiparesis due to disruption of the ascending and descending information passing through these structures.

Main vessels affected by stroke. Areas supplied by MCA: The bulk of the lateral surface of the hemisphere; except for the superior inch of the frontal and parietal lobe and the inferior part of the temporal lobe. Superior division supplies lateroinferior frontal lobe (location o Broca’s area i.e. language expression). Inferior division supplies lateral temporal lobe (location of Wernicke’s area i.e. language comprehension) Deep branches supply the basal ganglia and internal capsule. Areas supplied by ACA: The medial surface of the frontal lobe by the medial orbito-frontal artery, and parietal lobes. The anterior four- fifths of the corpus callosum. Approximately 1 inch of the medial surfaces of frontal and parietal lobes. Anterior portions of the basal ganglia and internal capsule; olfactory bulb and tract. Areas supplied by PCA: Occipital lobe. Branches supply cerebral peduncle; thalamus; corpus collosum.

Differentials?  Hypoglycaemia  Migraine  Focal epilepsy  Retinal bleeds  Intracranial tumours

Management of TIA?  Control CVS risk factors: BP; hyperlipidaemia; DM; smoking  Antiplatelet drugs: Clopidogrel; Aspirin & dipyridamole  Warfarin: Indication = cardiac emboli (AF; mitral stenosis; recent MI)  Carotid endarterectomy: not recommended for minor stenosis. Best performed with >70% stenosis. Should be performed within 2 weeks. Carotid Doppler used to monitor blood flow during surgery. Incision is made along the artery and plaques are removed. Alternative is to put a stent in.

What is ABCD2? 64 year old female is admitted with unilateral weakness that lasted around 45 minutes. What else do you want to know? No speech disturbance Blood pressure is 126/82 Diabetes diagnosed 2 years ago What is her score? 5

Thank-you! Any questions?