1. 2015 Joint Congress on Medical Imaging and Radiation Sciences Imaging and Intervention in Acute Stroke: MR Imaging in Acute Stroke Viesha Ciura, MD, FRCPC Neuroradiologist RCA/Mayfair Diagnostics Clinical Assistant Professor Department of Radiology University of Calgary May 29 th, 2015

2. Disclosures No disclosures

3. Objectives 1. understand the utility of MRI in acute stroke 2. identify which acute stroke patients are most likely to benefit from evaluation with MRI

4. Outline MRI sequences in acute stroke – DWI – MR perfusion – MRA The MGH Experience utility of MRI in acute stroke – determining stroke acuity – posterior circulation infarcts – lacunar infarcts – embolic infarcts – stroke mimics

5. Imaging Acute Stroke 4 critical questions: – is there intracranial hemorrhage? NCCT – is a large vessel occluded? CTA, MRA – is part of the brain IRREVERSIBLY injured? = CORE DWI > PWI > CTA-SI > NCCT – is there additional tissue AT RISK? = PENUMBRA NIHSS > PWI

6. Imaging Acute Stroke Gonzalez RG et al. The Massachusetts General Hospital acute stroke imaging algorithm: an experience and evidence based approach. J NeuroIntervent Surg 2013;5:7-12.

7. Why do we care about infarct core? determine which patients are likely to benefit from IA therapy for anterior circulation occlusion – cutoff of 70 mL, or approximately 1/3 of MCA territory – patients with infarct core >70 mL have poor clinical outcomes and higher mortality, regardless of treatment Yoo AJ, et al. MRI-based selection for intra-arterial stroke therapy: value of pretreatment diffusion-weighted imaging lesion volume in selecting patients with acute stroke who will benefit from early recanalization. Stroke 2009;40:2046-54. ABC/2

8. Is there additional tissue at risk? CBV MTT CBF courtesy Dr. Vincent Timpone

9. MR perfusion MRP in acute stroke: – selecting patients for reperfusion therapy (PWI-DWI mismatch) – not uniformly proven to predict a beneficial treatment response other potential roles – establishing diagnosis – TIA – predicting prognosis – guiding nonthrombolytic therapies designed to maintain cerebral perfusion (ie: blood pressure) concerns regarding repeatability, reliability and clinical efficacy takes TIME – acquisition, post-processing 40 million neurons! Copen WA et al. MR perfusion imaging in acute ischemic stroke. Neuroimag Clin N Am 2011;21:259-83.

10. MR perfusion for TIA establishing diagnosis difficult since patient symptoms have resolved, and cannot be evaluated by physical exam up to 17% of TIA patients suffer a stroke within 90 days of TIA – US, CTA or MRA may demonstrate stenosis that suggests a vascular origin – TIAs of cardioembolic origin occur in patients without vascular pathology PWI may be the only imaging indicator of ischemia Mlynash M et al. Yield of combined perfusion and diffusion MR imaging in hemispheric TIA. Neurology 2009;72:1127-33.

11. The MGH Experience Gonzalez RG et al. The Massachusetts General Hospital acute stroke imaging algorithm: an experience and evidence based approach. J NeuroIntervent Surg 2013;5:7-12.

12. “ED2CT” (to MRI) pre-hospital ED2CT page to techs, nurses, MDs ANGIO

13. Case 50 yo RHD woman, sudden onset left sided weakness, NIHSS 17

14. CT at outside hospital, 1.5 hrs after symptom onset IV tPA given 1 hr 45 mins after symptom onset

15. CTA 4.5 hrs after symptom onset

16. From CT table directly to MRI table DWI ADC

17. Arterial puncture 5.5 hours after symptom onset Stentriever device utilized to achieve recanalization

18. The Real World Experience When to consider MRI? – “negative” CT brainstem, lacunar, embolic infarcts – determining stroke acuity – young patient presenting with acute stroke – suspected stroke mimics

19. Case 63 yo M, found down, GCS 3, decerebrate posturing

20. NCCT

21. Coronal reformatted MIPs

23. Stentriever device in basilar artery and right PCA Initial angio Final angio -recanalized basilar artery -occlusion more distal right PCA

24. Case 34 yo F with vertigo, ataxia, vomiting, nystagmus

26. FLAIR ADC DWI T2W

27. FLAIR ADC DWI T2W LATERAL MEDULLARY INFARCT

28. T1W Right parasagittal T1W Left parasagittal TOF MRA collapsed MIP TOF MRA MIP Left vertebral artery dissection

29. Case 52 yo F with left-sided face and arm weakness

30. First MRI North of 60

34. When to consider MRI? “negative” CT determining stroke acuity – “waker uppers” or unknown time of onset – age-indeterminate lacunar infarct, no prior imaging young patient presenting with acute stroke suspected stroke mimics

35. Case 55 yo M with left face, arm, and leg weakness and paresthesias

36. ACUTE RIGHT PICA TERRITORY INFARCT?

37. ACUTE INFARCT RIGHT PONS, CHRONIC INFARCT RIGHT CEREBELLUM DWI ADC FLAIR

38. When to consider MRI? “negative CT” determining stroke acuity young patient presenting with acute stroke suspected stroke mimics

39. Case 5 yo F R arm and face weakness after temporal lobectomy for cortical dysplasia

40. FLAIR ADC DWI

41. FLAIR ADC DWI ANTERIOR CHOROIDAL ARTERY INFARCT

42. When to consider MRI? “negative” CT determining stroke acuity young patient presenting with acute stroke suspected stroke mimics – infection – seizure (status epilepticus) – neoplasm – PRES – demyelination

43. Right MCA infarct?

44. HSV ENCEPHALITIS

45. Right MCA Infarct?

46. STATUS EPILEPTICUS

47. Left MCA Infarct?

48. LOW GRADE GLIOMA

49. Embolic Infarcts?

50. METASTASES

51. Basilar Infarct?

52. OSMOTIC DEMYELINATION

53. Summary The MGH Experience – DWI to assist in patient selection for IA therapy – MR perfusion – limited role The Real World Experience – MRI as a problem-solving tool history ≠ CT findings – posterior fossa, lacunar, embolic infarcts suspected stroke mimic young patients MRI should not delay intervention – “time is brain”!

54. Acknowledgements some slides adapted from work developed by – Dr. R.G. Gonzalez, MGH – Dr. William Copen, MGH – Dr. Dan Boulter, The Ohio State University – Dr. Vincent Timpone, Wilford Hall Medical Center

55. References Gonzalez RG et al. The Massachusetts General Hospital acute stroke imaging algorithm: an experience and evidence based approach. J NeuroIntervent Surg 2013;5:7-12. Yoo AJ, et al. MRI-based selection for intra-arterial stroke therapy: value of pretreatment diffusion-weighted imaging lesion volume in selecting patients with acute stroke who will benefit from early recanalization. Stroke 2009;40:2046-54. Copen WA et al. MR perfusion imaging in acute ischemic stroke. Neuroimag Clin N Am 2011;21:259-83. Schaefer PW et al. Combining MRI with NIHSS thresholds to predict patient outcomes in acute ischemic stroke: value for patient selection. AJNR Am J Neuroradiol 2015;36:259–64. Mlynash M et al. Yield of combined perfusion and diffusion MR imaging in hemispheric TIA. Neurology 2009;72:1127-33. Boulter DJ, Schaefer PW. Stroke and stroke mimics: a pattern based approach. Semin Roentgenol 2014; 49:22-38.

56. Merci! Questions?