This presentation includes stroke and infarct latest defination an pathophysiology and CT MRI imaging features and management . This presntation help alot. Thanks

1. Role of imaging in stroke
management
Dr. Pradeep Kumar

7. DEFINITION:
• Stroke is a syndrome caused by disruption of the
blood flow to part of the brain due to either:
• (a) occlusion of a blood vessel (ischemic stroke,
seen in approximately 80% of cases); or
• (b) rupture of a blood vessel, resulting in injury
to cells and causing sudden loss of focal brain
functions.( Hemorraghic stroke).

8. Types:
• Hyperacute: <6 hrs
• Acute: 6-48 hrs.
• Subacute: 48 hrs-2wks.
• Chronic: > 2wks.

9. Etiology:
• Atherosclerotic: 40-45%
• Small vessel disease( lacunar infarct):15-30%
• Cardioembolic disease:15-25% MI, AF,valvular
disease.

10. • Pathogenesis:
cerebral blood flow(<15-18ml /100gm/min.)
O2 & glucose
ATP
Na –K ATPase
Na influx into cell
Cellular edema(cerebral edema)

11. • Nonenhanced CT is widely available, quick and no
contrast administration is required.

12. Early CT findings
Hyperdense MCA sign
• EARLIEST SIGN

13. Obscuration of lentiform
nucleus

14. Insular ribbon sign

15. NCCT in acute stroke
• OTHER EARLY SIGNS

17. • European Cooperative Acute Stroke Study
trial
• Alberta Stroke Program Early CT Score
(ASPECTS)

21. The main role of CT angiography is to
• reveal the status of large cervical
and intracranial arteries and
thereby help define the occlusion
site
• depict arterial dissection,
• grade collateral blood flow, and
• characterize atherosclerotic disease

22. • CT perfusion imaging can be used to measure the
following perfusion parameters:
• Cerebral blood volume (ie, the volume of blood per unit of
brain tissue; normal range, 4–5 mL/100 g);
• Cerebral blood flow (ie, the volume of blood flow per unit of
brain tissue per minute; normal range in gray
matter, 50–60 mL/100 g/min);
• Mean transit time, defined as the time difference between the
arterial inflow and venous outflow; and
• Time to peak enhancement, which represents the time from
the beginning of contrast material injection to the maximum
concentration of contrast material within a region of interest

23. • Knowing color scale is key.
• For TTP, higher scale (red) means longer TTP
(bad), and lower scale (blue) means shorter
TTP (good).
• For CBF, higher scale (red) means faster flow
(good), and lower scale (blue) means less flow
(bad).
• For CBV, higher scale (red) means more
volume (good), and lower scale less volume
(bad)

24. Ischemic core
Region of dec. blood
Penumbra
Well perfused area

30. • A thorough evaluation of acute stroke can be
performed by using a combination of
conventional MR imaging, MR angiography,
FLAIR images , and diffusion and perfusion-
weighted MR imaging techniques

31. FLAIR

33. • Diffusion-weighted imaging sequences now
are incorporated into most MR imaging
protocols and are essential components of an
acute stroke evaluation

34. Clinical Application

37. • While diffusion-weighted MR imaging is most
useful for detecting irreversibly infarcted
tissue, perfusion-weighted imaging may be
used to Identify areas of reversible ischemia as
well.

40. Subacute: 48hrs-2wks

41. 1

44. MR
• T1WI
○ Iso- to hypointense
○ May see T1 shortening (cortex, basal ganglia)
• T2WI
○ "Fogging effect" (isointensity)
• FLAIR
○ Hyperintensity corresponds to final infarct

45. Chronic cerebral infarct

49. Multiple embolic infarct

51. Lacunar infarct
• Lacunae are < 15mm CSF filled spaces or
holes.
• May be due to lipo hyalinosis and
atherosclerotic occlusion of perforating
arteries of circle of willis and peripheral
cortical branches or may be due to embolic
phenomenon.

59. Watershed or border zone infarct.
• Two types of vascular border zone:
External ( cortical ) : between ACA, MCA, PCA.
Internal (deep white matter) : between perforating
branches and major arteries.
• Etiology : emboli ( cortical more common ).
regional hypoperfusion( deep WM )
global ( all three cortical WS zone)
• Imaging:
External – wedge and gyriform shaped.
internal – rosary like line of white matter hyperdensites.

65. Current Thrombolytic and
Neurointerventional Techniques
• Alteplase, an intravenous tPA, is the only
thrombolytic therapy approved by the United
States Food and Drug Administration (FDA).

66. Catheter-directed Intraarterial
Thrombolysis
Intraarterial thrombolysis may be considered in
patients with an anterior circulation stroke that
is 6 hours old or less, who are ineligible for
intravenous thrombolysis, or in whom
intravenous thrombolysis was unsuccessful.
Intraarterial thrombolysis may be performed as
much as 24 hours after a posterior circulation
stroke

67. Embolectomy and
Mechanical Disruption Devices
• MERCI clot retriever and PENUMBRA
aspiration system has been approved by FDA

68. MERCI clot retriever:
• The retriever consists of a long thin wire with a helical coil formed at the
distal end. A balloon catheter is snaked into the affected vessel from
the femoral artery, and the balloon is inflated to prevent blood flow that
could hinder the retrieval process. The retriever is then fed through the
catheter, during which the distal coil is straightened to fit through the
catheter tube. When the retriever emerges at the clot site, the coil
reforms, wrapping around the clot and allowing the clot to be removed
with the catheter.

71. Thank you