Advances in CT Technology: Implications for the Diagnosis and Treatment of Stroke
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Stephen Huff, MD
Advances in CTAdvances in CTTechnology:Technology:
Implications for the Diagnosis Implications for the Diagnosis and Treatment of Stroke and Treatment of Stroke
Stephen Huff, MD
Stephen Huff, MDStephen Huff, MD
Associate ProfessorAssociate Professor
Department of Emergency MedicineDepartment of Emergency MedicineUniversity of VirginiaUniversity of Virginia
Stephen Huff, MD
DisclosuresDisclosures
• Executive Board, Foundation for Education Executive Board, Foundation for Education and Research in Neurologic Emergenciesand Research in Neurologic Emergencies
Stephen Huff, MD
CTA and CTPCTA and CTP• Essential questionsEssential questions
• Is there hemorrhage?Is there hemorrhage?• Is there a stroke?Is there a stroke?• Is there large vessel occlusion?Is there large vessel occlusion?• Is there “irreversibly” infarcted Is there “irreversibly” infarcted
core?core?• Is there “at risk” penumbra?Is there “at risk” penumbra?
• One contrast bolus yields two One contrast bolus yields two datasetsdatasets• Vessel patencyVessel patency• Infarct versus salvageable Infarct versus salvageable
penumbrapenumbra
Stephen Huff, MD
CT Angio & PerfusionCT Angio & Perfusion
Stephen Huff, MD
CT Perfusion TerminologyCT Perfusion Terminology
Blood FlowBlood Flow Blood VolumeBlood Volume Mean Transit TimeMean Transit Timeoror
Time to PeakTime to Peak
Stephen Huff, MD
DefinitionsDefinitionsPerfusionPerfusion The steady-state delivery of blood The steady-state delivery of blood
to cerebral tissue through the to cerebral tissue through the capillariescapillaries
Cerebral Blood Flow (CBF)Cerebral Blood Flow (CBF) Volume flow rate of blood Volume flow rate of blood through the cerebral vasculature through the cerebral vasculature per unit timeper unit time
Cerebral Blood Volume (CBV)Cerebral Blood Volume (CBV) Amount of blood in a given Amount of blood in a given amount of tissue at any timeamount of tissue at any time
Mean Transit Time (MTT)Mean Transit Time (MTT) Average time it takes for blood to Average time it takes for blood to traverse from the arterial to the traverse from the arterial to the venous side of the cerebral venous side of the cerebral vasculaturevasculature
Stephen Huff, MD
Changes in Cerebral Vascular Physiology Changes in Cerebral Vascular Physiology with Worsening Circulatory Impairmentwith Worsening Circulatory Impairment
CBFCBF CBVCBV MTTMTT
Salvageable Salvageable PenumbraPenumbra
↓↓ ↑↑ ↑↑IrretrievableIrretrievableInfarctInfarct
↓↓ ↓↓ ↑ ↑ ↑↑
Stephen Huff, MD
Relationship between CBV, Relationship between CBV, CBF, and MTTCBF, and MTT
MTT= Blood Flow / Blood VolumeMTT= Blood Flow / Blood Volume
Blood FlowBlood Flow Blood VolumeBlood Volume Mean Transit TimeMean Transit Timeoror
Time to PeakTime to Peak
Stephen Huff, MD
Case:Case:Value of CTA/CTP within 3 hour windowValue of CTA/CTP within 3 hour window
• 50 yo male50 yo male• CT within hour of CT within hour of
symptom onsetsymptom onset• Awake, alert, dysarthricAwake, alert, dysarthric• Fixed right sided gazeFixed right sided gaze• Left sided weaknessLeft sided weakness
Initial
Stephen Huff, MD
Case:Case:Value of CTA/CTP within 3 hour windowValue of CTA/CTP within 3 hour window
Stephen Huff, MD
Case:Case:Value of CTA/CTP within 3 hour windowValue of CTA/CTP within 3 hour window
BF BV TTPInitial
Stephen Huff, MD
Case:Case:Value of CTA/CTP within 3 hour windowValue of CTA/CTP within 3 hour window
BF BV TTP 3 day fuInitial
Stephen Huff, MD
Case:Case:“Wake up” Stroke“Wake up” Stroke
0735 at outside hospital
Stephen Huff, MD
Case:Case: “Wake up” Stroke “Wake up” Stroke
Stephen Huff, MD
Case:Case: “Wake up” Stroke “Wake up” Stroke
1030 at stroke center
Stephen Huff, MD
Case:Case: “Wake up” Stroke “Wake up” Stroke
24 hours later at stroke center
Stephen Huff, MD
ConclusionsConclusions• CTA identifies an occlusive lesion• Core infarct (not reversible):
Poor blood flow and blood volume with extremely long transit time
• Ischemic penumbras (reversible):Poor blood flow with increased blood volume and some increase in transit time
• CTA can distinguish these two• Perhaps IV tPA use can be optimized• Standard: give IV tPA if
within 3 hours
Stephen Huff, MD
Questions?Questions?J. Stephen HuffJ. Stephen Huff
huff@virginia.eduhuff@virginia.edu
www.ferne.orgwww.ferne.org
ferne_emra_2007_caseconf_huff_cta_100907_finalcd04/22/23 09:36
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