role of imaging in the diagnosis and mangagement of acute cerebral infarction

7/29/2019 Role of Imaging in the Diagnosis and Mangagement of Acute Cerebral Infarction

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Susan Liu HokiGillian Lieberman, MD

Role of Imaging in the

Diagnosis and Mangagementof Acute Cerebral Infarction

Susan Liu Hoki, Harvard Medical School Year IIIGillian Lieberman, MD

July 2002


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Goals

Understand how imaging studies help instroke diagnosis and management throughexamining findings in patients at differentstages of acute ischemic stroke

Know the advantages of different tests in

stroke imaging


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Background: Stroke

Stroke is a lay term meaning a conditiondue to vascular lesions of the brain causedby hemorrahage, embolism, thrombosis, or

rupturing aneurysm

Primarily diagnosed clinically andconfirmed and followed through imagingtests


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Background: Stroke TypesMost common stroke etiologies:

1) Cerebral Infarction 80%2) Primary Intracranial Hemorrhage 15%3) Nontraumatic subarachnoid hemorrhage 5%

* FOCUS: Acute Cerebral Infarction


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Menu of Radiological Tests Cerebral Angiogram

CT: w/ or w/o contrastCT angiogram (CTA)

MR: w/ or w/o contrast T1 or T2 weighted (T1WI, T2WI)FLAIR

Diffusion weighted image (DWI)SusceptibilityMR angiogram


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Cerebral Angiogram Gold standard in the

past Outdated and

replaced byMRI/MRA High risk of

producing furtherthrombus formationin brain and causingrenal failure

Courtesy of Dr. Steve Reddy, BIDMC


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Patient 1: CT w/o ContrastTest of Choice in Emergencies

Normal findings Left MCA HemorrhageCourtesy of Dr. Nicole Nelson, BIDMC

Hyperdense areaof hemorrhageseen clearly on CT

1) Distinguish between ischemic and hemorrhagic stroke

2) Normal CT in patient with


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CT Findings in Cerebral InfarctionHyperacute:


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MR Findings in Cerebral InfarctionImmediate

Hyperintense on DWI(low apparent diffusioncoefficient, ADC) IV contrast enhancement perfusion alterations


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Treatment and Further Imaging After the initial CT scan, patient is treated with

1) tPA2) anti-coagulants3) antiplatelet aggreating agents

Further studies help in evaluating response totreatment and extent of brain damage notdetected on the initial CT

The following images presented will be of CT,CTA, MR, and MRA studies, which are most

commonly used at large hospitals


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The Ideal Early Patient Comes into the ER presenting with a recent

onset of stroke symptoms CT scan shows no hemorrhage and no

changes seen in ischemia Patient has no other contraindications for

rtPA therapy

rtPA is administered Follow progress with sensitive MR studies


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Patient 2:DWI Hyperacute Infarction Stage

HISTORY

38 y.o. womaninpatientdevelops right

hemisphericstrokesymptomswhile talking

with physician MRI studies


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Patient 3:Contrast-enhanced T1W

4 hrs after left MCAsymptoms began

Extensive Intravascularenhancement seen (an

immediate finding)

Osborn, Diagnostic Neuroradiology, 1994

S Li H ki


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Our Patient: Ms. JB

79 y.o. brought by her son who found her sittingon a chair in her bedroom, unresponsive. CC: unable to move left arm/leg no known cardiovascular disease PMH: TB exposure s/p Rx, sinusitis, arthritis DX: Acute Stroke

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JB: Early Stroke Findings on CT

NormalHyperdenseInsular Cortex

Courtesy of Dr. Barbara Appignani, BIDMC

Hypodensity and lossof gray and whitematter differentiation

right insula

Insular Ribbon Sign

Lenticular nucleus

part of internalcapsule

-InternalCapsule

-Damagedregion

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Hyperdensity inthe ProximalRight MCA

Courtesy of Dr. Barbara Appignani and Dr. Nicole Nelson, BIDMC

JB: Early Stroke Findings on CTNEXT:

-Patient startedon aspirin, BPcontrolled

-MR studies 6

hrs later

SusanLiuHoki


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JB: MRI-T2 Weighted Image


-T2W: good

anatomical detail-T2 signalhyperintensity in RMCA territory:R insula, basalganglia and internalcapsule-no shift in midlinestructures

6 hrs afterinitial CT

SusanLiuHoki


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JB: MR-DWI


-Findings similar tothose in T2WI

hyperintensity in RMCA territory:R insula, basal

ganglia and internalcapsule-Note less anatomical

detail compared to T2WI, but morestriking signal

6 hrs afterinitial CT

SusanLiuHoki


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JB: MRA 3-D Reconstruction


-KEY FINDING:

Absence of flow in RMCA branches

-Study pinpoints

artery location withproblem in flowthrough in R MCAterritory

Circle of WillisInternal Carotid ArteryAnterior Cerebral ArteryMiddle Cerebral Artery (MCA)

Absence of flow

C

SusanLiuHoki


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Patient 3: Ms. FL 86 y.o. with a history of atrial fibrillation

who was at home walking towards herhusband when she collapsed and becamesomulent

Unable to speak and had difficulty movingher right side clinical dx of acute stroke

CT scan w/o contrast 2 hrs after onset wasnormal Timingappropriate for rtPA

rtPA contraindicated since INR>1.5

SusanLiuHoki


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Ms. FL:MR T2-Weighted 2 days later

Courtesy of Dr. Nicole Nelson, BIDMC

FINDINGS :

Striking enhancement of brain parenchyma

Mass effect associatedwith infarct, mild midlineshift

Both commonly found1-3 days post-stroke45 hrs after

symptom onset

SusanLiuHoki


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FL: MR FLAIR

Courtesy of Dr. Nicole Nelson, BIDMC

FLAIR technique is

similar to T2WI exceptthat CSF signal issubstracted to more

accurately representhyperintense signal fromfluid produced bydamaged cells

45 hrs aftersymptom onset

Susan Liu Hoki


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Susa u oGillian Lieberman, MD

CT Findings in Cerebral InfarctionHyperacute:


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Gillian Lieberman, MD

MR Findings in Cerebral InfarctionImmediate

Hyperintense on DWI(low apparent diffusioncoefficient, ADC) IV contrast enhancement perfusion alterations


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Summary: Goals in Imaging PatientsPresenting with Clinical Signs of

Acute Stroke

Confirm clinical diagnosis CT Distinguish between hemorrhagic and

ischemic stroke, since treatment differsgreatly CT

Assess the severity of brain damage andfollow progression of damage MRstudies, plus CT to monitor newhemorrhage

Susan Liu Hoki


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Summary: Goals in Imaging PatientsPresenting with Clinical Signs of Acute Stroke

2) MR1) CT

Hemorrhage No Hemorrhage

Signs of Ischemia?

Severity?R/O Non-

stroke causesof symptoms

Assess severity,follow progress

T1WI T2WI DWI FLAIR Succeptibility

Susan Liu Hoki


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Summary Neuroradiology is important in confirming

the diagnosis of acute cerebral infarctionand monitoring progression Advances in MR techniques make early

diagnosis and assessment possible, whichare necessary in thrombolytic therapy to

prevent irreversible brain damage

Susan Liu Hoki


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References Adams Jr., Harold P., Gregory J. del Zoppo, and Rdiger von

Kummer. Management of Stroke: A Practical Guide for thePrevention, Evaluation, and Treatment of Acute Stroke, 2nd ed., WestIslip, NY: Professional Communications, Inc., 2002.

Castillo, Mauricio. Neuroradiology Companion, 2nd ed. , Philadelphia:Lippincott-Raven Publishers, 1999.

Nolte, John. The Human Brain , 4 th ed., St. Louis: MosbyYearBook, Inc., 1999./SLIDE #11

Osborn, Anne G. Diagnostic Neuroradiology. St. Louis: Mosby Year Book, Inc., 1994./SLIDE #8, 9, 13

Susan Liu Hoki


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Acknowledgements

Barbara Appignani, MD

Nicole Nelson, MD Steve Reddy, MD

Gillian Lieberman, MD Pamela Lepkowski Larry Barbaras and

Cara Lyn Damour

Susan Liu Hoki


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The End

role of imaging in the diagnosis and mangagement of acute cerebral infarction

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