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Radiologic Findings of Ischemic Stroke

Radiologic Findings of Ischemic Stroke. Natalia Markiewicz M4 September 24 th 2009. Risk Factors. Most Important: Hypertension Age Other: Smoking, Diabetes Mellitus, Hyperlipidemia, Atrial Fibrillation, CAD, Previous stroke/TIA, Family History.

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Radiologic Findings of Ischemic Stroke

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  1. Radiologic Findings of Ischemic Stroke Natalia Markiewicz M4 September 24th 2009

  2. Risk Factors Most Important: Hypertension Age Other: Smoking, Diabetes Mellitus, Hyperlipidemia, Atrial Fibrillation, CAD, Previous stroke/TIA, Family History

  3. Main subtypes of Ischemic Stroke Embolic stroke • Etiology: Cardiac, Arterial, Aorta, Paradoxical Thrombotic stroke • Etiology: Large and small vessel disease Systemic hypoperfusion • Etiology: Cardiac pump failure, Reduced cardiac output

  4. Clinical Features Embolic stroke • Occur suddenly with maximal deficit initially • Clinical features depend on the artery occluded Thrombotic stroke • Symptoms progress in a stepwise fashion with some periods of improvement Systemic hypoperfusion • Symptoms are diffuse, nonfocal, and typically bilateral

  5. Neuroimaging Non-contrast CT to exclude or confirm hemorrhage

  6. Non-contrast CT Patient presents within 0-3hrs of symptom onset. What is the next step in the management of this patient? Treatment: IV Thrombolytic Therapy

  7. Non-contrast CT Patient presents within 3-6hrs of symptom onset. What is the next step in the management of this patient? Establishing if there is any DWI/PWI mismatch: THE PENUMBRA

  8. Penumbra • Occlusion of an intracranial vessel leads to a fall in cerebral blood flow to zero, causing death of the brain tissue: core region of infarction (irreversible) • Tissue surrounding this core infarction is ischemic but salvageable (the penumbra) • The penumbra will eventually die if no change in blood flow occurs • Goal of thrombolytic therapy is to save the penumbra by restoring circulation

  9. Diffusion-weighted imaging Reveals evidence of ischemic injury within 3-30 minutes of onset. Signal reflects irreversibly damaged brain tissue.

  10. Perfusion-weighted imaging Measures the passage of contrast agent such as gadolinium through the brain parenchyma over time. Constructs maps of cerebral blood volume. Detects the entire region of hypoperfusion.

  11. The Importance ??? PWI/DWI mismatch: physiological evidence that there is brain tissue that can be salvaged with successful recanalization via tPA.

  12. References Harvard University Department of Radiology www.massgeneralimaging.org Kidwell, CS, Chalela, JA, Saver, JL, et al. Comparison of MRI and CT for detection of acute intracerebral hemorrhage. JAMA 2004; 292:1823. Smith, WS, English, JD, Johnston, SC. “Ischemic Stroke.” Harrison’s Online. Chapter 364.

  13. Questions Thank you

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