STATE OF THE ART IMAGING OF ACUTE STROKE

Transcription

1 STATE OF THE ART IMAGING OF ACUTE STROKE Marin Penkov UH St Ivan Rilski Sofia RadiologyTogether 2-3 June 2017

2 GOALS The concept and significance of penumbra CT and MRI Basic Principles Clinical application Comparison between methods

3 Introduction Brain damage with acute onset 80% from all strokes Important factor for death and disability New methods of treatement new requirements Conception of penumbra

4 ACUTE ISCHEMIA Central Core Periferial zone stuned cells Abnormal evoked potentials Reduced function Salvageable region Early recanalization

5 4 P Р parenchyma P pipes P perfusion P penumbra Rowley HA.The four P-s of acute stroke imaging: parenchyma, pipes, perfusion, and penumbra. AJNR Am J Neuroradiol 2001;22:

6 Imaging Methods MDCT MRI DSA Lopez AD et al. Lancet 2006; 367: Rothwell PM et al. Lancet 2005; 366: JT et al. Lancet Neurol 2003; 2:89-98

7 Targets Early detection of ishemic stroke Exclusion of intracranial hemorage Extra- intracranialcirculation and intravascular trombi rcbv, rcbf, MTT - perfusion Penumbra

8 CT At presentation 3h 24 h 2 days Ribbon sign

9 NECT Еuropean Cooperative Acute Stroke Study The Alberta Stroke Program Early CT Score (ASPECTS) National Institutes of Health Stroke Score (NIHSS) Radiographics, Vol23#3, May-June2003,p

10 CT Angio l l l l l l Common technology Exra- intracranial vessels Aortic arc/ Circle of Willis Intravenous thrombolysis Intraarterial thrombolysis Thrombosis severity RadioGraphics 2006; 26:S75 S95

11 CT ANGIO

12 CT PERFUSION rcbv 4-5 ml/100 g RCBF ml/100g min MTT Time to Peak Functional Hemodynamic maps The regions with reduced perfusion are positive immediatly after occlusion Penumbra 100% sensitivity Small volume Courtesy of B.Penev Tokuda Hospital Sofia

13 PERFUSION rcbv rcbf MTT Oligemia Normal or elevated Moderately reduced Prolonged Penumbra Normal or mildly decresased Markedly reduced Prolonged (>150%) Core Severely reduced <2ml/100 g Severely reduced Strong prolongation or not measurable

14 CT PERFUSION Courtesy of B.Penev Tokuda Hospital Sofia

15 МRI Better sensitivity Conventional methods (T2, FLAIR, T1, SWAN T1 +C ) DWI/ADC PWI (rcbv,rcbf, MTT) ASL? MRA 3D/2D TOF MRA + C MRS DTI

16 DWI Define the core minutes after onset Difference between chronic and acute

17 DWI

18 РWI rcbv 4-5 ml/100 g RCBF ml/100g min MTT Time to Peak Functional hemodinamyc maps The regions with reduced perfusion are positive immediatly after occlusion Penumbra 100% sensitivity DWI/PWI mismatch

19 PDM DWI inreversibly damaged tissue PWI - oligemia PDM (perfusion/diffusion mismatch) tissue at risk Viability and size of penumbra change dynamicallyin responce to regional CBF, pathophysiological environment and treatment Penumbra may resolve spontaneously Merging with core Becomming normal tissue By early recanalizational therapy the penumbra may be salvaged

20 PDM PDM does not optimally define ischemic penumbra PWI>DWI PWI=DWI PWI<DWI DWI in early phase overestimates infarct core PWI overestimates penumbra MISMATCH PENUMBRA MATCH No tissue at risk REPERFUSION Chen F, Ni YC. Magnetic resonance diffusion-perfusion mis-match in acute stroke. World J Radiol 2012; 4(3): Trombolysis No Trombolysis No Trombolysis Heiss WD. The concept of the penumbra: can it be translated to stroke menagment? Int J Stroke 2010; 5: Kidwell CS, Alger JR, Saver JL. Elvolving paradigms in neuroimaging of the ischemic penumbra. Stroke 2004; 35:

21 Take home mesages PDM is not yet perfectly matched with the ischemic penumbra, but it has been widely recognized as a crude and practical approximation of an imaging equivalent of the pathological ischemic penumbra Although MR is curently the preferred method for determining core and penumbra, CT perfusion is comparable and potentially more avaible PWI overestimates penumbra - include oligemia Acute stroke patients with a significant missmatch between DWI/ PWI are likely to benefit from reperfusion Acute stroke patients with little or no missmatch between DWI/ PWI may not benefit may even be harmed Future PDM validation is forthcoming ( studies based on larger cohort)

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