Updated in Diagnosis of Acute Ischemic Stroke: CT/MRI and advances

Updated in Diagnosis of Acute Ischemic Stroke: 
CT/MRI and advances 
Nguyen Quang Anh, MD 
VIETNAM NATIONAL CONGRESS OF CARDIOLOGY 
15th Meeting, Ninh Binh 
Introduction 
• Ischemic: 80% of stroke 
• 3rd leading cause of dead in United States 
• 2025: prediction of 1.2 millions patients/year 
• In Viet Nam, stroke is top cause of Death (account 
for 18% - 2008) 
• Cardiovascular disease, diabetes 
Diagnostic Tools 
• Multi-choices in diagnosis 
• CT Scanner -> MRI (3 steps) 
• Perfusion -> Multiphase 
CT Scanner protocol 
• CT non-contrast: rule out hemorrhage + identify ischemic 
stroke area 
• CT Angiography: arterial occlusion 
• PW: if possible (double dose of contrast) 
MRI protocol 
• T2*: rule out hemorrhage + identify cerebral 
microbleeding 
• DWI: core of infarction 
• FLAIR: parenchymal lesion/ absence of “flow voids” in 
the occluded artery 
• TOF 3D: arterial occlusion site 
• PW: if possible 
Non-contrast 
 • “Emergency imaging of the brain is recommended before 
any specific treatment for AIS. Non-enhanced CT will 
provide the necessary information for initial treatment of 
IV r-tPA (Class I; level of Evidence A - same as 2013)*” 
*AHA/ASA-stroke guide line 2015 
CT Non-contrast 
• Rule out the hemorrhage 
• Identify ischemic lesion 
• Tips: 
• Change the window level 
–C: 8 
–W: 32 
- Rule out hemorrhage 
- Identify cerebral microbleeding 
 -> risk factor of bleeding after 
treatment 
T2* 
Kidwell Stroke 2002; Nighoghossian Stroke 2002; Derex Cerebrovasc Dis 2004 
Identify occlusion site 
T2* 
Acute stage < 6h 
Acute stage (6-24h) 
Early sub-acute stage: 48hrs - 3 weeks 
Late sub-acute stage 
Chronic stage 
ASPECTS 
• ≥ 6: favorable clinical outcome* 
*Stroke, 2008. 39(8): p. 2388-2391 
• ≥ 6: favorable clinical outcome* 
L 
ASPECTS 
 • ≥ 8: favorable clinical outcome* 
Pc-ASPECTS 
*Stroke, 2008. 39(9): p. 2485-90 
• DWI = irreversible lesion = core of infarction 
• Bigger core, worse outcome 
• In the MCA occlusion, core volume in DWI > 100cm3 
-> no indication of treatment (>1/3 territory of MCA) 
• >70cm3: poor prognosis even rapid recanalization* 
• <70cm3: good outcome (64%) after quick recanalization 
• Other studies**: 
– V <16cm3: good outcome 
– V >36cm3: bad result 
Volume of the core 
(*) Stroke, 2009. 40: p. 2046-2054 
(**)Stroke, 2011. 42(5): p. 1251-4. 
Volume 
V30cm3 N 
mRS ≤ 2 69 4 73 
mRS > 2 21 37 58 
Correlation between Volume of infarction 
and clinical recovery in our study 
• V<30cm3: good prognosis 
p < 0.05 
(*) Nguyen Duy Trinh, Pham Minh Thong 2014 
Angiography 
CT Angiography (MSCT) 
• “A non-invasive intracranial vascular study is strongly 
recommended. If not possible at the time of initial 
imaging, r-tPA should done first then try vascular imaging 
as quickly as possible (Class I, level A - New)” 
*AHA/ASA-stroke guide line 2015 
CT Angiography 
MIP (Single phase) VRT 
MRI TOF 3D 
Perfusion 
CT Perfusion 
• “The benefit of CT perfusion, DWI/perfusion-weighted 
imaging for selecting patients (ASPECTS<6) for 
endovascular therapy are unknown (Class IIb; level C - New). 
Further randomized, controlled trials should be done*” 
*AHA/ASA-stroke guide line 2015 
Lesions = Core 
(irreversible )+ penumbra 
(reversible) 
CT 
Perfusion 
MTT: mean transit time, CBF: Cerebral Blood Flow 
TTP: Time to peak, CBV: Cerebral blood volume 
MTT 
CBV CBF 
TTP 
DWI PERFUSION - MECHANISM 
MRI Perfusion 
Match PW/DW -> no 
penumbra -> no indication 
of treatment 
Mismatch PW/DW 
-> good indication 
for treatment 
Case 
Before 
DWI DWI PWI PWI 
After 
 • Sn of PW ~[74-84%], Sp of PW ~[96-100%] 
• Mismatch DW/PW = penumbra area 
• (PW – DW)/ DW x 100% > 20% -> significant difference* 
DWI/PW 
(*) EPITHET study-Stroke, 2009. 40: p. 2046-2054 
 CT Scanner 
– Low sensitivity; PW only for anterior 
circulation (64 slices) 
– 2 times of contrast (Angio & PW) 
– Can not discover micro bleeding 
– Quick 
– Patient unstable -> fast scan 
– Widespread access 
– In case of contraindication with MRI 
(Stent, pacemaker) 
 MRI 
• Very high Sv & Sp; PW for 
whole brain 
• Only 1 time of contrast (PW) 
• Identify micro bleeding 
• A little slower but acceptable 
• Patient need to be very stable 
• Mostly in big hospital 
• No radiation 
Comparison 
New update 
• CT Angiography Multiphase is a good choice 
• Simple procedure 
• Just published in 2015 
• Data from PRoveIT (Menon et al) 
• N = 147, comparison between CT Multiphase, single 
phase and CT Perfusion 
Protocol 
• Non contrast first then multiphase 
• Phase 1: 
• Evaluate the carotid and brain 
circulation 
• Double scan with contrast, then 
subtraction algorithm 
• Phase 2: 
• Just only the brain 
• Time for moving table+scan 
• Total 8sec 
• Phase 3 
• Similar to phase 2 
 Menon et al., (2015). Neuroradiology, 000 (0). 
Evaluation 
 Menon et al., (2015). Neuroradiology, 000 (0). 
Evaluation scale 
Điểm Đánh gia ́ (khi so sánh với bán cầu bên bệnh với bên lành) 
0 Không quan sát thất bất kỳ nhánh mạch máu nào đi vào vùng nhồi máu tại 
bất kỳ phase nào 
1 Có một vài nhánh mạch máu nho ̉ đi vào vùng nhồi máu tại bất kỳ phase nào 
2 Chậm 2 phase hiện hình mạch máu vùng ngoại vi VÀ giảm đậm độ-tốc độ 
ngấm thuốc, HOẶC chậm 1 phase nhưng có vùng không có mạch máu 
3 Chậm 2 phase hiện hình mạch máu vùng ngoại vi, HOẶC chậm 1 phase 
nhưng sô ́ lượng mạch máu trong vùng nhồi máu giảm 
4 Chậm 1 phase hiện hình mạch máu vùng ngoại vi, nhưng đậm độ và tốc độ 
ngấm thuốc thì tương tự 
5 Không có chậm phase, quan sát thấy ngay các nhánh mạch máu bàng hệ đi 
vào bình thường hoặc nhiều hơn trong vùng nhồi máu 
• 0-3: nghèo bàng hệ (poor)̣, 4: vừa (moderate), 5: tốt (good) 
• Left M1 occlusion (19h00’ ASPECTS ~ 8 point) 
Case 2a 
• Male, 75 years old, history of cardiac coronary disease 
• Stroke during hospitalizing time (17h30’) due to chest pain 
• Right hemiplegia, unconscious, G~13pt, NIHSS = 19 
PHASE 1 PHASE 2 PHASE 3 
• Multiphase score ~ 4 point (good collateral) 
Multiphase 
TTP 
(Time to Peak) 
CBF 
(Cerebral Blood Flow) 
CBV 
(Cerebral Blood Volume) 
• Mismatch > 35% 
Perfusion 
DSA (19h50’ – 20h10’) 
• Solitaire 6/20: 1 times 
• TICI 3 
Follow up 
• G ~ 15pt 
• NIHSS ~ 6pt 
• mRS ~ 2 after 2 days 
Case 2b 
• Female, 57 years old; Atrial fibrillation, still using anticoagulant 
• Administered to BM hospital in 2nd hours (13h15’->14h30’) 
• Left hemiplegia, NIHSS = 18 
• Right ICA occlusion (14h45’ ASPECTS ~ 6 point) 
PHASE 1 PHASE 2 PHASE 3 
Multiphase 
• Multiphase score ~ 2 point (poor collateral) 
DSA (15h15’ – 15h57’) 
• Solitaire 6/30: 4 times 
• TICI 3 
MRI follow up 
• G 15pt 
• NIHSS ~ 9pt 
• mRS ~ 4 after 2 wks 
Conclusion 
• CT Scanner noncontrast and MSCT is very important 
and always/strongly recommended in AIS (in new 
guideline 2015) before any treatment – easy and 
accessible in all hospital 
• MRI only in big hospital, very useful especially in 
unknown time stroke patients/ same function as CT 
• DWI/PW: good information but need more trial to prove 
its evidence and cut-off volume in prognosis 
• CT Multiphase: new choice and simple, also need more 
trials and time 
THANK YOU FOR YOUR ATTENTION