This document summarizes advances in imaging for ischemic stroke. It discusses the role of CT angiography (CTA) in detecting vessel occlusion and infarct core. Several major clinical trials demonstrated the benefits of endovascular therapy for certain patients. Guidelines now recommend endovascular treatment for those meeting specific criteria within 6 hours of onset. CT perfusion can identify penumbra and guide patient selection. While MRI is most accurate for core imaging, the time required may delay treatment. Faster door-to-treatment times are important to improve outcomes. Advanced imaging like CTA helps identify patients most likely to benefit from endovascular intervention.

1. ADVANCES IN IMAGING OF
ISCHAEMIC STROKE IMAGING
Vipul Gupta
Neurointerventional Surgery
(Interventional Neuroradiology)
Artemis Hospital, Gurgaon

2. Advances in Stroke imaging …
 Acute stroke imaging – clinical approach
 Vessel wall imaging
 Neurointerventional suite imaging
 TCD – integration in clinical practice

3. MR CLEAN Trial
Netherlands, 2015
ESCAPE Trial
Canadian, 2015
EXTEND-IA Trial
Australian, 2015
SWIFT PRIME Trial
USA, 2015
REVASCAT Trial
Spanish, 2015

4. AHA/ ASA guideline 2015:
Patients should receive endovascular therapy with a stent retriever if they meet all
the following criteria (Class I; Level of Evidence A). (New recommendation):
 prestroke mRS score 0 to 1
 acute ischemic stroke receiving intravenous r-tPA within 4.5 hours of onset
 causative occlusion of the internal carotid artery or proximal MCA (M1)
 age ≥18 years
 NIHSS score of ≥6
 ASPECTS of ≥ 6
 treatment can be initiated (groin puncture) within 6 hours of symptom onset

5. Advanced Imaging:
CTA used to detect MVO
CT Perfusion:
 SWIFT Prime – Criterion changed (71 with perfusion; 125 without)
 possibility that patients who may have responded to therapy were excluded.
Site of occlusion should be documented:
 studies not designed to validate the utility of the advanced imaging selection criteria

6. Imaging approaches for case selection
 NCCT (ASPECTS)- NIHSS
 NCCT & CTA, CTA-SI
 NCCT, CTA & CTP
 MRI-DWI, (MRA, PWI)
What information is needed?
• Bleed
• Infarct core – is critical 70-100 ml
• Major vessel occlusion
• Tissue at risk- penumbra
Time, imaging interpretation, unstable patients

7. Imaging…
 Hemorrhage
# NCCT- excluding hemorrhage is necessary and sufficient for IV –tPA
# MR- quite good, expert interpretation
 Major vessel occlusion
# CTA better & quicker than MRA for MVO
# Can be obtained without slowing IV thrombolysis.
 Core
# Most accurate - DWI.
# NCCT – least
# CT A- SI- better than NCCT
# CT perfusion- CBF, CBV, MTT – better
 Penumbra
# MVO with small core (CTA-SI or DWI)- penumbra is usually there
# CT perfusion
# MR perfusion???

8. NCCT & CTA, CTA-SI….
Benefits of CTA:
 Presence of proximal occlusion
 Core on CTA source images
 Collateral circulation assessment
 Arch anatomy - facilitate DSA
 Other - unstable aortic thrombus, arterial dissections
 Hemorrhage, major vessel occlusion- very good
 Infarct core- good
 Penumbra- small core with MVO, collaterals (Calgary group)- reasonable
 Issue- interpretation

9. Left terminal ICA with Bovine arch Type 2 and type 3 arches
Extra stiff
wire for
exchange
Penumbra 3 Max and 4 Max
DAC 0.044 to cross loop
Contralateral approach
Penumbra 3Max through PCOM/ Solumbra

10. •68/M, DM, HTN, CAD, underwent PTCA to LAD
•Admitted for surgery of aortic stenosis.
•Double anti-platelets was stopped
•Patient developed acute onset right side weakness
with aphasia.
IV- tPA given, no improvement

12. Futile recanalization….

13. ASPECTS scoring (tricky)

14. Good collaterals by the Miteff method (OR, 3.341; 95% CI, 1.203–5.099; P .014) was the independent predictor of
good outcome amongst various collateral grading scales.
Arterial Collateral status – penumbra,
retention of penumbra

15. Miteff system.A, Contrast opacification all sylvian branches. B, Some vessels can be seen at the Sylvian fissure.C, distal
cortical filling alone

16. Multipha
se CTA
Better able to predict outcomes than single phase and perfusionCT

17. CT, CTA, CTP….
CT perfusion imaging
MTTCBF CBV
Quantitative CTP mismatch classification using relCBF and Tmax is similar to perfusion-diffusion MRI.
Stroke. 2012 Oct;43(10):2648-53. Epub 2012 Aug 2.
Incremental improvement in interobserver reliability was demonstrated for NCCT, CTA-SI, and CTP-
CBV, respectively. (Stroke. 2013;44(1):234-6) 25.

18.  Left hemiplegia, left UL and LL 0/5
 5:14AM

19. 6:22AM

20. 8:07 AM
Patient made gradual recovery
Left LL 4/5 and UL 3/5 - 30 day follow up mRS at 90
days- 0

21. Patient presented with in 2 hours
Futile IV tpa

22. • 60 years old female.
• h/o hypertension and hypothyroidism
• Acute onset left hemiparesis and left facial weakness
• CT Brain , CTP and CTA done 6 1/2 hours after ictus.

24. CT, CTA, CTP
 Hemorrhage, major vessel occlusion- very good
 Infarct core- CBV, good ? Better than SI
 Penumbra- CBF & MTT vs CBV
 Over all sensitivity and specificity – 80-90%
 Interpretation – convenient in emergency, technical issues are
there

25. MRI
Adv
Best for core – DWI
No radiation or contrast
Can do MRA and perfusionimaging
But
•Time…..time…..time…..
•Shifting, checking forCI, MRA and perfusion time
•Sick restless patients
•MRA- not good enough
•Key- should not be delaying IV tPA
•Having one protocol for all acute stroke patients
•Every 30 min delay – 10% decrease possibility of good
outcome (IMS-II)
Hand PJ, Wardlaw JM, Rowat AM, et al. Magnetic resonance brain imaging in patients with acute stroke: feasibility and patient related difficulties. J Neurol Neurosurg Psychiatry
2005;76:1525–27
Goyal M AJNR 33 August 2012

26. Every 30-min delay in angiographic reperfusion reduced the relative likelihood of a
good clinical outcome by 12% in adjusted analysis.

28. Conclusion
• Improving door to puncture time may be the key
SNIS – 2015 …
• Target Door to puncture < 60 min
Door to recanalization <90 min
• Small steps make a big difference!!!

29. Thrombus imaging
•Length
•Type
•Fragmentation

30. Vessel wall imaging
•MR vessel wall imaging is a powerful tool for extracranial (eg, carotid)
plaque characterization, enabling the determination of stroke risk from
carotid plaque rupture
•The Multi-Ethnic Study of Atherosclerosis carotid MR imaging study first
reported associations of carotid plaque features with future events. It
showed that the remodeling index and lipid core presence measured
on MR imaging added a risk for a new event beyond traditional risk
factors in individuals without a history of cardiovascular disease.

34. ICAD

37. DynaCT stents

38. syngo® Neuro PBV IR
Neuro Parenchymal Blood Volume1. DynaCT – Mask Acquisition
2. Steady State
Contrast Injection
3. DynaCT –
Fill Acquisition
Segmentation
of Bone and
Air
–
Subtracted Image
remove
Detection of
Arterial
Input normalize
Smoothing
0
10
5
mL/100g
PBV Map

39. Case study 1:
65 male with vascular risk factors
Diagnosed with asymptomatic carotid
stenosis
Underwent VMR testing
Why?
Meta-analysis - odds ratio of 3.86 (95%
CI, 1.99–7.48) for stroke risk
Technique:
Breath hold at end of inspiration for 30
seconds
Uncooperative patients – re breath
Always compare with the opposite side
Formula – MFV (end) – MFV (start)/ MFV (
start) x 100/ seconds of breath holding
< 0.6 is impaired

40. Vasomotor reserve testing

41. Criterion for MES
 3 db higher than background
 Unidirectional (spatial > 7.5 mm and
temporal > 30 ms)
 MCA positive slope
 ACA negative slope
Case study 2
60 male with left sided minor stroke
Started on dual antiplatelet
Had a further event
Planned for MES testing

43. Study 3
 61 year male patient
presented in ER with c/o
severe headache a/w nausea
since one day.
 NCCT Head shows SAH
Pulsatility index
•ICP
•Distal spasm

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45. Thank you ….