2. Prof. dr. Arif Faisal, Sp.Rad(K), NKL, DHSM
Professor of Radiology Department, Faculty of
Medicine Public Health and Nursing, Universitas
Gadjah Mada
Curriculum Vitae
Educational Background
• 1976: Medical Doctor-Universitas Gadjah Mada
• 1981: Radiology Specialist (Sp.1)-Universitas Gadjah Mada
• 1998: Diploma in Health Services Management, Edith Cowan University, Perth
Consultant
• 2001 : Consultant specialist in Oncology Imaging
• 2018 : Consultant specialist in Neuroradiology, Head and Neck
Work Experience
• 1977-2018: Lecturer of Universitas Gadjah Mada
• 1987-1994: Head of Radiology Department-Universitas Gadjah Mada
• 1994-2001: Deputy Director of Dr.Sardjito Hospital, Yogyakarta
• 2001-2009: President Director of Dr. Soeradji Tirtonegoro Hospital, Klaten
• 2010-2018: President Director of Academic Hospital-Universitas Gadjah Mada
• 2010-2013: Head of Radiology Study Program-Universitas Gadjah Mada
3. Prof. dr. Arif Faisal, Sp.Rad(K), NKL, DHSM
IMAGING TECHNOLOGY FOR STROKE
4. Stroke Definition
(WHO,2013)
Stroke:
a clinical syndrome consisting of rapidly developing clinical signs
of focal (or global in case of coma) disturbance of cerebral
function lasting more than 24 hours or leading to death with no
apparent cause other than a vascular origin.
Transient Ischemic Attack (TIA):
Stroke resolve completely within 24 hours
5. MAJOR CATECORIES OF STROKE
1. ISCHEMIC:
- interruption of blood supply – 87%
- thrombosis & emboli
2. HEMORRHAGIC:
- rupture of blood vessel / abnormal
vascular structure – 13%
Hemorrhagic Transformation:
- Some hemorrhagices develop inside
areas of ischemic
*
*
6. 1. To differentiate the ischemic from haemorrhagic stroke and intracerebral
haemorrhages → non-contrast CT (NCCT) is the primary modality.
2. To exclude other causes of stroke (i.e., stroke mimics such as tumors,
seizure, etc.).
3. To determine vascular territory of stroke and location and extent of
intravascular clot.
4. To estimate the volume and location of the infarcted tissue and tissue at
risk for infarction.
5. To find the occluded artery in ischemic stroke and to help the treatment
planning.
Shafaat et al. Stroke Imaging. Statpearl (Internet) National
Library of Medcine 2022.
The main reasons of neuroimaging in stroke
7. o CT based
Non contrast CT (NCCT)
CT angiography (CTA)
CT perfusion (CTP)
CT venography (CTV)
o MRI based
T1,T2, Gradient Recalled Echo (GRE)
Susceptibility-weighted imaging (SWI)
Fluid Attenuated Inversion Recovery (FLAIR)
Diffusion Weighted Imaging (DWI)
MR angiography (MRA)
MR perfusion (MRP)
Imaging Technology
13. Hypertensive patient: Hyperacute hematoma → the right
internal capsule and insular cortex
T1W image
Iso-hypointense
T2W image:
Hyperintense
GRE image
Low intensity
MRI In Hemorrhagic Stroke
14. Stages of hematoma evolution on MRI
Five stages of hematoma evolution are recognized :
1. Hyperacute (<1 day)
- intracellular oxyhemoglobin (T1: isointense; T2: isointense to hyperintense; DWI: high; ADC: low)
2. Acute (1 to 3 days)
- intracellular deoxyhemoglobin; T1: remains isointense to hypointense; T2: signal intensity drops
to become hypointense; DWI: low; ADC: low)
3. Early subacute (3 to 7 days)
- intracellular methemoglobin (T1: signal gradually increases to become hyperintense; T2: remains
hypointense; DWI: low; ADC: low)
4. Late subacute (7 to 14-28 days)
- extracellular methemoglobin (T1: remains hyperintense; T2: signal gradually increases; DWI: high;
ADC: low)
5. Chronic (>14-28 days)
1. periphery
- intracellular hemosiderin (T1: hypointense; T2: hypointense)
2. center
- extracellular haemichromes (T1: isointense; T2: hyperintense; DWI: low; ADC: high)
Gaillard F. Hemorrhage on MRI. Radiopedia 2022.
15. The mnemonic in haemorrhagic on MRI
• I Bleed DWI-ADC: HILO
• T1 Isointense
• T2 Bright
• hyperacute <1 day
• I Die DWI-ADC: LOLO
• T1 Isointense
• T2 Dark
• acute 1 to 3 days
• Bleed Die DWI-ADC: LOLO
• T1 Bright
• T2 Dark
• early subacute 2 to 7 days
• Bleed Bleed DWI-ADC: HILO
• T1 Bright
• T2 Bright
• late subacute 7 to 14-28 days
• Die Die DWI-ADC: LOHI
• T1 Dark
• T2 Dark
• chronic >14 to 28 days
16. CT and MRI images intracerebral haemorrhage (horizontal arrows). The vertical arrow in
the GRE-MRI scan → the artefact caused by magnetic field inhomogeneity at the
CSF/bone/air interface.
CT T2WI GRE
4,5 h
2 h
Kakkar et al. Current approaches and advances in the imaging of stroke. Dis Model Mech. 2021;
14(12):dmm048785. Published online. Doi: 10.1242/dmm.048785.*
17. CT versus MRI scans for detecting
stroke.
(A,B) A haemorrhage can be seen
clearly in the CT scan (A; white
arrow), less evident in an MRI scan
(B; white arrow).
(C,D) An ischaemic infarct faintly
visible in the CT scan (C; blue arrow),
clearly visible in MRI scan (D; blue
arrow).
haemorrhage
Ischemic infarct
18. FLAIR images (M) → multifocal areas of hypointensities, mainly lobar in location, surrounded by
hyperintense margins representing edema. T2*GRE image (N) → “blooming” representing multiple
acute ICHs. Two days later, follow-up NECT (O) → multiple ICHs with surrounding moderate edema.
FLAIR NECT
T2*GRE
Elmegiri et al. MRI Characterization of Non-traumatic Intracerebral Hemorrhage in Young Adults. Front
Neurol. 2020, 11.588680 doi. 10.3389/fneur.2020.558680
20. Depend on the age of infarction:
- Hyperacute (less than 12 hours)
→ exclude intracranial hematoma, hyperdense vessel sign
- Acute (12 to 24 hours)
→ cytotoxic oedema (hypodense), loss of grey-white matter interface
- Subacute (24 hours to 5 days)
→ vasogenic oedema (hypodense) with mass effect and herniation
- Chronic/old (within weeks after stroke)
→ volume loss, encephalomalacia
NCCT findings in ischemic stroke
21. Key CT Technique in Ischemic Stroke
A. Non Contrast CT (NCCT)
B. CT Angiography (CTA)
C. CT Perfusion (CTP)
22. - Detection hemorrhage or non-hemorrhage
- Detection early-stage acute ischemia:
= hyperdense vessel sign → thrombosis
= the insular ribbon sign→ hypodensity
= obscuration of the lentiform nucleus.
= loss of contrast between gray matter and white matter
A. Non Contrast CT
Hyperdense
vessel sign
Insular ribbon sign
– cytotoxic edema
Obstruction lentiform
nucleus + loss
contrast W-G
23. Exemplary NCCT with the labeled
ASPECTS regions (ASPECTS 10),
based on MCA:
M1: anterior middle cerebral artery
(MCA) cortex/frontal operculum;
M2: MCA cortex lateral to insular
ribbon/anterior temporal lobe;
M3: posterior MCA cortex/posterior
temporal lobe;
M4: anterior MCA territory superior to
M1; M5: lateral MCA territory superior
to M2; M6: posterior MCA territory
superior to M3;
I: insula; C: caudate; L: lentiform
nucleus; IC: internal capsule.
McDonough et al. State of the Art Stroke Imaging: A Current Perspective. Canadian Association of Radiologists
Journal, 2022, 73(2):371-383. https://doi.org/10.1177/08465371211028823
Ischemic stroke
24. B. CT - Angiography
Hyperdense proximal left MCA
(thrombosis)
Absence of MCA segmen
(occlusion)t
26. To measure perfusion parameters:
1. Cerebral blood volume (CBV): the volume of blood per unit of brain
tissue; normal range, 4–5 mL/100 g;
2. Cerebral blood flow (CBF): the volume of blood flow per unit of brain
tissue per minute; normal range in gray matter, 50–60 mL/100
g/min;
3. Mean transit time (MTT): the time difference between the arterial
inflow and venous outflow;
4. Time to peak enhancement, the time from the beginning of contrast
material injection to the maximum concentration of contrast
material within a region of interest (ROI)
C. CT Perfusion
29. A central irreversibly infarcted tissue core surrounded by a peripheral region of
stunned cells that is called a penumbra
Reversible
Irreversible
30. A 41-year-old obese, normotensive female developed left-sided hemiplegia at
6 a.m.
CT at 7.30 CBF CBV CT-Angio 6 wks after
stroke
After thrombolysis
32. MRI In Ischemic Stroke
a.To distinguish hemorrhagic from infarct
b.Shows the vascular anatomy on suspected venous infarction
or carotid or vertebral dissections
c. Shows better an acute ischemic lesion than CT
34. CT MRI
Detection of hemorrhage Detection of hemorrhage with SWI
Angiography, better resolution Angiography, non-contrast
Faster, more available, less restrictive
Slower, limited availability, restrictive
environ
Radiation No radiation
Limited in posterior fossa Better detection in posterior fossa
Limited detection of small lesions Better detection of small lesions (DWI)
Less specific in detection of “stroke
mimics”
Better detection of “stroke mimics,”
especially on contrast-enhanced scans
Comparison between MR and CT perfusion
in ischemic stroke
SWI=Susceptibility-weighted imaging; DWI= Diffusion-weighted imaging
Vymazal et al. Comparison of CT and MR imaging in ischemic stroke.
Insights Imaging 2012:619-627
36. Right middle cerebral artery infarction.
DWI:
Restricted water
diffusion
ADC:
Decreased
signal
Fast spin echo T2-
weighted fat
suppressed image
37. – Acute ischemic stroke with cytotoxic edema:
→ decrease water diffusion in infarcted tissue:
- increased DWI → hyperintense
- decreased ADC → hypointense
– Acute ischemic stroke with vasogenic edema:
→ increase water diffusion
- increased DWI signal (T2 shine)→ hyperintense
- increased ADC → hyperintense
DWI and ADC
Provides a quantitative measure of the water diffusion.
38. 1. Diffusion image → area with irreversible changes (dead issue).
2. A large area with hypoperfusion.
3. Diffusion-perfusion mismatch → blue, can be saved with therapy.
1 2 3
39. Modern concept of ischemic
penumbra.
Early abnormality on DWI equals
the infarct core plus a part of the
tissue at risk (penumbra); and the
perfusion deficiency on PWI
includes the infarct core plus
penumbra and region of benign
oligemia. PWI-DWI mismatch
(PDM) does not optimally define the
ischemic penumbra.
Chen et al. Magnetic resonance diffusion-
perfusion mismatch in acute ischemic stroke:
An update. World J Radiol 2012; 4(3): 63-74.
DOI: 10.4329/wjr.v4.i3.63]
40. • Infarct:
- Decreased Cerebral Blood Volume (CBV)
→ final infarct area
• Penumbra:
- Normal Cerebral Blood Volume (CBV)
- Low Cerebral Blood Flow (CBF)
- High Mean Transit Time (and Time To Peak)
→ may or may not survive the ischemic insult.
Imaging of Penumbra: CTP & MRP
41. Conclusions
1. CT and MRI are the best imaging technology to establish a
diagnosis of stroke.
2. CT is the most widely used first-line imaging tool in patients with
acute stroke and to differentiate cerebral infarction and
hemorrhage.
3. Multimodal CTA-CTP and MRA-MRP delineate the hemodynamics
of ischemic stroke that may be used to guide treatment decisions
and prognosticate regarding expected outcomes.
