Imaging Evaluation of SAH and Aneurysm

Overview

  • Subarachnoid Hemorrhage (SAH)
    • Ruptured intracranial aneurysm (80% of non-traumatic cases).
    • Vascular malformations (up to 5% of cases).
    • Imaging workup
      • Non-enhanced CT (NECT) of the head (sensitivity 98%)
      • CTA
        • Performed if NECT positive
        • Specificity 100%, sensitivity 96-99.7% for >4mm aneurysms
      • MRI/MRA
        • Uncommonly used for acute SAH
    • For more information, please see the corresponding chapter in Radiopaedia
  • Intracranial Aneurysms
    • Incidence of intracranial aneurysms is 2-3% in the general population
    • Saccular aneurysms
      • Typically arise at arterial branch points
      • Far more common than intracranial arterial dissections and dissecting pseudoaneurysms
      • May be associated with high velocity flow phenomena
        • Feeding vessels to dural AVFs
        • Feeding and intra-nidal AVM vessels
        • Vessels associated with infection, trauma, and neoplasm
          • Cause fewer than 5% of all aneurysms
      • Acute onset of severe headache is the typical presentation indicating aneurysm rupture
      • Progressive sequela
        • Acute hydrocephalus
        • Vasospasm
        • Cerebral edema
        • Ischemic infarct
        • Herniation
        • Coma
        • Death
    • For more information, please see the corresponding chapter in Radiopaedia

  • Imaging workup
    • CTA superior to MR for detection
    • MRI/MRA for surveillance of unruptured/treated aneurysms
    • DSA
      • Gold standard for evaluation of aneurysms detecte...
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