Imaging the TIA Patient

1
Imaging the TIA Patient

• Christopher Lewandowski, MD
• Henry Ford Hospital
• May 2009

2
Case

• SB is a 57 yo AAF with a past history of DM II
  and hyperlipidemia who come to the ED with sudden
  onset of R chin, R tongue, and later R sided
  numbness. Her R leg felt weak with walking. Onset
  -2 hrs PTA
• VS 180/90 P-82, RR-16, T-36.5 c
• PE revealed decrease to pinprick on R face, arm,
  and leg. Sx resolved shortly after arrival
• Now what?

Image the patient
3
Purpose of Imaging

• Exclude non-cerebrovascular causes
• of focal neurologic deficits
• Determine if the event was a stroke or a TIA
• Determine the etiology
• cardiogenic, non-cardiogenic
• large vessel disease, small vessel disease
• Treatment Decision

4
Treatment Options

• Risk Factor Control
• Antiplatelet
• Anticoagulation
• Carotid endarterectomy (CEA)
• stent (CAS)
• PFO closure
• Intracranial stenosis stent (wingspan)

5
What needs to be Imaged
6
Non-contrast CT -Head

• AHA Guidelines
• general agreement that patients should receive
  a CT scan of the head .. to exclude a rare lesion
  such as a subdural hematoma or brain tumor (Class
  III, type C).
• CT may reveal an area of brain infarction . 29
  to 34 of patients. may influence subsequent
  management (Class III, type C)
• CT of the head has a limited role in
  vertebrobasilar TIA (Class III).

Culebras, Stroke 1997 281480-1497
7
Utility of the Non-contrast CT-Head

• Douglas 322 pts ED diagnosis of TIA, CTlt48h
• Normal 46
• New infarct 4
• Old stroke 21
• Non-ischemic cause 1.2
• 3-tumors, 1-chronic subdural
• Risk of stroke at 90d 10.9
• Highest risk with new infarct on initial CT
  (5/13)
• OR 4.06 for stroke in 90d

Douglas VC, Stroke.2003 Dec34(12)2894-8
8
Is an MRI better for new infarcts?

• DWI is very sensitive for early ischemia
• Kidwell, 42 patients with TIA
• DWI in 20/42, 48
• DWI patients
• Longer duration of sx (7.3h v 3.2h)
• DWI changed the suspected cause in 33
• Not all DWI lesion evolved into strokes
• 50 reversible

Kidwell, Stroke 1999 301174-1180
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DWI for TIA

• Crisostomo, 75 patients with 78 TIAs
• DWI lt 3days
• 21 (16/78) DWI
• 7/16 DWI pts also on T2 or FLAIR
• DWI pts had
• Sx gt1h
• Motor deficits
• Speech deficits

Crisostomo, Stroke 2003 43932-937
10
DWI predicts risk

• Ay, 87 pts admitted with TIA
• DWI 41.3 (36/87)
• DWI 19.4 inpatient risk of recurrent stroke
• Coutts, 120 pts minor stroke or TIA (57.5)
• DWI-, no vessel occl 4.3 90d risk
• DWI, no vessel occl 10.8 90d risk
• DWI, vessel occl, 32.6 90 d risk

Coutts, Ann Neurol 200557848 Ay, Ann Neurol
2005, 57679
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Clinical Score Imaging risk assessment

• Ay, 601 TIA patients, all with MRI
• Clinical score DWI to predict 7d stroke risk
• ABCD2 gt 4 2.0 7d risk
• DWI 4.9 7d risk
• ABCD2 gt 4, DWI 14.9 7d risk

Ay, Stroke 200940181-6
12
What About PWI

• Restrepo, 22 pts with TIA and DWI/PWI
• 12 DWI (54)
• 7 PWI (32) (14 only PWI)
• 4 DWI and PWI (18)
• 15 DWI or PWI (68)
• Krol, 69 pts with TIA, 62 had PWI
• 21 PWI (34)
• 12 PWI and sx resolution
• No relation of PWI to clinical outcome

Restrepo, AJNR 2004251645 Krol Stroke 2005
362487-89
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DWI/PWI

• Mlynash, 43 TIA patients
• DWI / PWI within 48 hrs
• PWI 33 (16 only PWI)
• DWI 35
• DWI and PWI 16
• DWI or PWI 51
• PWI lesions more frequent with
• MRIlt12 hrs, speech deficit, lt60 yo
• PWI increases the sensitivity of MRI for ischemia

Mlynash, Neurology 2009 72(13) 1127-33
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DWI

• Precise evaluation of TIA
• 40 of TIA pts have DWI (25-67)
• increased risk of recurrent stroke
• Guides localization and treatment
• Identifies patients to admit
• PWI
• identifies another 3-14 of TIA patients with
  ischemia/hypoperfusion, significance uncertain

15
Imaging of Vessels in TIAAHA Guidelines

• A noninvasive screening technique is indicated
• carotid duplex or Doppler ultrasonography
• MRA provides noninvasive imaging
• leads to overestimation of degree of arterial
  stenosis (Class II)
• high-quality MRA
• sufficient vascular overview for
  vertebrobasilar ischemia
• contrast-enhanced CT scanning ..
• may be helpful as a screening tool in centers
  where it is available (Class III)
• radiographic arteriography (DSA)
• best defines surgically remediable lesions
• recommended for a symptomatic patient when
  noninvasive tests indicate 70 occlusion

16
Duplex US

• Anatomic US image Doppler flow velocity
• Carotid lesions are found in 8-31 of TIA pts

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Imaging of the neck

• Doppler US is the standard initial evaluation
• Advantages
• Inexpensive
• Reliably excludes critical stenosis,lt 50
• Disadvantages
• Operator dependant
• Over-estimates stenosis
• Can be limited by severe calcifications
• 88 sensitivity, 76 specificity

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CT Angiogram

• Advantages
• perform with CT-head
• available, accurate
• Images head and neck
• Disadvantages
• cost
• contrast
• radiation
• reformatting

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How good is CT-Angiogram

• Josephson 81 vessels with both CTA and DSA for
  stenosis gt70, 2 blinded readers
• Agreed on 78/81, 96 95CI90-99
• CT-A 100 sensitive, 63 specific
• NPV of CTA for stenosis gt70 100
• Comparable to MRA
• Wyers 59 pts with 3-D CTA and planned carotid
  stent
• influenced the planned approach in 37
• reliably identified anatomic contraindications to
  CAS without DSA

Josephson, Neurology 200463457-60 Wyers, J Vasc
Surg 2009 49614-22
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What about contrast nephropathy

• Josephson reviewed 1,075 patients that underwent
  CT-A and CT-Perfusion
• 52 creatinine increased by gt 0.5
• 4 possible renal failure due to contrast
• 2 temporary hemodialysis

Josephson, Neurology 2005641805-6
21
MR angiogram
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MRA

• Advantages
• Completed with DWI and entire sequence
• Covers head and neck
• Disadvantages
• Availability, cost
• Patient exclusion, tolerance
• Gadolinium
• Image acquisition time
• MRA
• 92 sensitivity 76 specificity
• CE-MRA
• 94 sensitivity 93 specificity

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DUS, MRA, DSAWhich one when?

• Busken 350 pts with DUS, MRA, and DSA
• DSA gold standard
• DUS
• 88 sensitive 76 specific
• MRA
• 92 sensitive 76 specific
• Strategy of DUS, then MRA
• 96 sensitive 80 specific
• DUS alone was the most efficient strategy, adding
  MRA as necessary

Busken, Radiology 2004233101-112
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What is the best strategy

• Wardlaw,
• Can DUS, CTA, MRA, or CE-MRA replace DSA
• Literature review with expert panel
• 41 studies, 2404 pts, 22 different strategies
• For 70-99 Stenosis
• CE-MRA most accurate 94 sens, 93 specific
• DUS, CTA, MRA all similar
• 89 sens, 84 specific
• For 50-69 Stenosis
• Literature overestimates accuracy because the
  sensitivity/specificity is better in asymptomatic
  arteries
• 1st DUS, confirm with CE-MRA

Wardlaw JM, Health Technol Asses 2006301-182
25
What do vascular surgeons do?

• Long 2002, survey of 382 vascular surgeons in
  France, 9390 stenoses
• Decision for surgery based on
• DUS DSA 69
• DUS MRA 14
• DUS CTA 9
• DUS alone 8

Long, Ann Vasc Surg 2002 16261-5
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What about Intracranial (IC) Stenosis

• Transcranial Doppler TCD
• Advantages
• Noninvasive, easy to perform
• Disadvantages
• operator dependant
• Rely on appropriate
• bone windows

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TCD for IC Stenosis

• Feldmann 407 pts, SONIA Trial
• All patients with TCD, MRA, DSA
• TCD 50 PPV, 85 NPV
• MRA 66 PPV, 87 NPV
• Low incidence of IC stenosis
• TCD provides similar information as MRA
• Zubkov 93 pts with AIS,
• CTA found 10 occlusions, 22 stenosis (EC/IC)
• Good correlation with DUS
• CTA demonstrates IC stenosis better than TCD

Feldmann, Neurology 2007682099-2106 Zubkov,
Neurol Res, 20088835-8
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What if you do find a IC stenosis

• WASID study
• IC stenosis gt50 after TIA or minor stroke
• 90d risk of Stroke - 4.7
• 90d risk of TIA - 6.9
• After TIA alone
• 60 (15/25) events occur w/in 90 days
• Treatment
• Antiplatelet agents
• stent under study (Wingspan)

Ovbiagele, Arch Neurol 2008 65(6)733-7
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Imaging the Heart ECG

• ECG Primarily for dx of Atrial Fibrillation
• Christensen ECG of 233 TIA pts
• Abnormal in 44 (ectopic beats and AV block)
• No ECG finding was assoc with poor outcome or
  mortality
• Elkins 1327 pts ED dx of TIA and ECG
• 2.3 with new AF
• 4.2 with abnormal ECGs had cardiac events
• Abn ECG LVH, AF, AV conduction delays
• Cardiac event AMI, CHF, Arrhythmia, ACS
• vs 0.6 with normal ECGs (OR 6.9 1.6-29.5)
• No increase risk of stroke or death with abnormal
  ECG

Christensen, J Neurol Sci 200523499-103 Elkins,
Arch Neurol 2002591437-41
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Cardiac Monitoring

• Purpose is to find Paroxysmal Atrial Fib
• Jabaudon 149 pts with stroke or TIA
• ECG for AF 2.7 - on day 1 (4/149)
• 4.1 - by day 5 (6/145)
• 24 hr Holter 5 w AF (7/139)
• 7d ELR 5.7 w AF (5/88)
• Tayal 56 pts- cryptogenic stroke
• 21 d of OPD monitoring, 23 w AF
• AF detected 7-21 days, 0 lt 7 d
• Low yield in general, consider longer monitoring
  if cardioembolic cause suspected

Jabaudon, Stroke 2004351647-1651 Tayal,
Neurology 2008, 181696-701
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EchocardiographyA traditional part of the TIA
evaluation

• 3 yield in unselected patients
• Suspect cardiac source
• Young patients
• No large vessel source or
• no small vessel disease
• Known cardiac disease
• AF (atrial thrombi)
• valvular disease, valve replaced
• Dilated cardiomyopathy
• Endocarditis
• TEE gtgt TTE for
• Aortic arch atheroma
• Atrial thrombi
• Valvular disease
• R to L shunts (PFO)

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Transesophageal Echocardiography

• Force 132 pts with TIA / minor stroke
• 70 -known cause, 62 cryptogenic
• TEE Positive for PFO/ASA in
• 3 w known cause
• 19 w cryptogenic
• deBruijn TEE gtTTE
• 231 TIA patients, both TTE TEE
• 55 (127/231) potential source
• 39 (90/321) only on TEE
• 40 of pts with (-) TTE had ()TEE

Force, Clin Neirol Neurosurg 2008110779-83 deBru
ijn, Stroke 2006 372531-2534
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SummarySimple and Rapid approach

• SOS-TIA (Lancet Neurlogy Nov 20076953-960)
• MRI or CT, DUS, EKG, TTE or TEE as needed
• 90d stroke risk 1.24
• EXPRESS (Lancet 2007369254-55)
• CT, ECG, DUS, TTE or TEE as needed
• 90d stroke risk 2.1
• EDOU (Stead, Neurocrit Care, 2008)
• CT, EKG, DUS,
• neurology consult with further testing as needed
• 90d stroke risk 2.4
• 80 Risk reduction

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SummaryWhat do you need to do

• Do something, and do it quickly
• Brain imaging CT or MRI
• Connect to CTA or MRA if possible
• Vascular imaging DUS
• Cardiac Imaging ECG, monitor
• TEE or TTE as indicated

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Back to the Case

• ECG- normal
• Monitor NSR
• CT normal
• DWI
• MRA normal
• TEE normal
• Discharged
• ASA, Simvistatin, glucatrol

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Stroke, 2009 June 402276-2293