1. María Hernández-Pérez, Josep Puig, Gerard Blasco, Laura Dorado, Natalia Pérez de la Ossa, Antoni Dávalos, Josep Munuera EP-68 Assessment of collateral blood flow with dMR at 3T in Acute Stroke Patients

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3. Importance of every part of the arterial tree in acute ischemic stroke Site of occlusion Status of arterial circulation beyond the occlusion Functionality of leptomeningeal collaterals Predictors of recanalization and clinical outcome Background Bang, Stroke 2011 Bang, J Neurol 2008

4. Gold standard Invasive Time consuming Good visualization of site of occlusion and collaterals No hemodynamic information Well validated indirect assessment Post-process No hemodynamic information Background Conventional angiography CTAMR PWI derived indexes

5. Four-dimensional MR angiography (dMRA) is a time-resolved sequence that enables the hemodynamic study of cerebral blood vessels. Mainly used in arterio- venous malformation and vascular tumours. Background

6. We evaluated the ability of dMRA to determine the grade of occlusion and collateral blood flow in acute ischemic stroke patients. Purpose

7. Consecutive patients undergoing 3T-MRI within 12h of anterior circulation large artery occlusion MR protocol · SWI/GRE · DWI · FLAIR · TOF · dMRA · PWI Demographic variables Stroke severity Clinical variables Methods Clinical variables MR protocol

8. dMRA 3D-contrasted enhanced time resolved MR angiography with stochastic trajectories TE 1.17ms TR 3.15ms flip angle 25 Section thickness 2.5mm Acquisition bandwidth 650 Hz 30 dynamic acquisitions 2.28 sec per volume Total acquisition time 90 sec 8 Methods

9. 9 Evaluation by two independent readers Site of occlusion TIMI grades 0: no perfusion 1: penetration without perfusion ASITN collateral grading system 0: no collaterals 1: slow collaterals, persistence of some defect 2: rapid collaterals, persistence of some defect 3: slow collaterals, complete angiographic blood flow 4: rapid complete collateral blood flow TMax>2s vol x Collateral circulation deficit TMax>6s vol Vol of tissue with TMax>2s and TMax <6s DWI lesion volume ADC <600 PWI lesion volume TMax>6s 2: delayed, partial perfusion 3: complete perfusion

10. CLINICAL CHARACTERISTICS n=21 Age (years)63.4 ± 17 Gender (women)12 (57.1%) Baseline NIHSS17 [8-21] 21 patients finally included Results

11. RADIOLOGICAL FEATURES: differences TOF / dMRA TOF dMRA Site of the occlusion Extracranial ICA Intracranial terminal ICA Tandem + terminal ICA + M1 M1 3 (14.3%) 2 (9.5%) 1 (4.7%) 0 1 15 (71.4%) 3 (14.3%) 0 (0%) 4 (19%) 2 14 (66.7%) TIMI 0 1 2 3 NA 14 (66.7%) 4 (19.1%) 0 (0%) 3 (14.3%) 10 (47.6%) 5 (23.8%) 2 (9.5%) 1 (4.8%) 3 (14.3%) Results

12. RADIOLOGICAL DYNAMIC FEATURES (exclusive dMRA) n=21 Arterial collateral grade 0 1 2 3 4 0 (0%) 9 (42.9%) 0 (0%) 9 (42.9%) 3 (14.3%) Asymmetrical clearance deep veins3 (14.3%) Asymmetrical clearance superficial sinuses 11 (52.4%) Incomplete filling : 9 Complete filling : 12 Interreader agreement ACGk=0.93

13. Complete (n=12) Incomplete (n=9) DWI lesion volume (cc) p= 0.012 Complete (n=12) Tmax >6s volume (cc) p= 0.028 Incomplete (n=9) Complete (n=12) Collateral circulation deficit p= 0.009 Incomplete (n=9) Results

14. Arterial occlusionComplete collateral filling DWI lesion volume 14.61ml Tmax>6s volume 36.8ml Arterial occlusion Incomplete collateral filling DWI lesion volume 63.32ml Tmax>6s volume 216.7ml Results

15. dMRA at 3T is a fast, direct, feasible, noninvasive, reliable way to assess collateral circulation This technique provides profound insights into hemodynamic alterations in acute stroke patients dMRA is potentially useful for the evaluation of vascular occlusion and secondary effects throughout the vascular system; future studies should explore this role. Conclusions 1 2 3