Stroke Imaging & Diagnostics Flashcards
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Read the first 7 Stroke Imaging & Diagnostics flashcards as text
A transesophageal echocardiogram (TEE) reveals a patent foramen ovale (PFO) with atrial septal aneurysm in a 38-year-old with cryptogenic stroke. What is the significance of this combined finding?
Answer: The combination significantly increases the risk of paradoxical embolism compared to PFO alone
PFO combined with atrial septal aneurysm carries a substantially higher risk of paradoxical embolism and recurrent stroke than PFO alone, informing closure decisions.
Which technique in CT angiography allows assessment of intracranial collateral vasculature most comprehensively in acute ischemic stroke?
Answer: Multiphase CTA (mCTA) with acquisitions in arterial, peak venous, and late venous phases
Multiphase CTA captures arterial, peak venous, and late venous phases, allowing assessment of leptomeningeal collateral filling that single-phase CTA misses due to timing variability.
What does a negative DWI in a patient with clinical posterior circulation stroke symptoms most likely indicate?
Answer: Early posterior fossa ischemia that may be below DWI detection sensitivity in the acute phase
DWI can be falsely negative in early posterior fossa ischemia due to technical limitations and small lesion size; clinical suspicion should guide repeat imaging.
On MR spectroscopy in an acute stroke patient, which metabolite change reflects neuronal loss and irreversible infarction?
Answer: Decrease in NAA with increase in lactate
Decreased NAA reflects neuronal death, while elevated lactate confirms anaerobic metabolism in infarcted tissue; together they indicate irreversible injury on MR spectroscopy.
Which imaging protocol component is essential before administering IV tPA to ensure hemorrhage is excluded?
Answer: Non-contrast CT of the brain
Non-contrast CT is the required and sufficient imaging to exclude intracranial hemorrhage before IV tPA administration according to AHA/ASA guidelines.
A stroke patient's MRI shows restricted diffusion in a cortical and subcortical pattern following a specific vascular territory with hemorrhagic petechiae on GRE. What pattern does this most likely represent?
Answer: Arterial territorial infarction with hemorrhagic transformation
Cortical/subcortical restricted diffusion in an arterial territory with petechial hemorrhage on GRE is consistent with hemorrhagic transformation of an arterial ischemic infarct.
Transcranial Doppler (TCD) microemboli monitoring detects high-intensity transient signals (HITS). In a patient with recently symptomatic carotid stenosis, what do HITS indicate?
Answer: Active microemboli generation from the stenotic lesion, indicating high early stroke risk
HITS on TCD represent microemboli passing through the insonated vessel and indicate active embolization from an unstable plaque, which is associated with high early recurrent stroke risk.