MD Conference Express ISC 2012 - (Page 25)
These findings indicate that baseline DWI lesions are reliably incorporated into the 5-day FLAIR lesion; ie, that “DWI reversibility” is minimal. In addition, tissue that remains hypoperfused (Tmax >6 sec) following endovascular therapy is very likely to progress to infarction. Treatment Implications of the Malignant MRI Profile Michael Mlynash, MD, MS, Stanford Stroke Center, Palo Alto, California, USA, discussed the endovascular treatment implications of the malignant MRI profile, which is defined as a large baseline DWI lesion and/or a large and severe baseline PWI lesion. This profile has previously been shown to predict poor outcomes following intravenous tPA therapy [Albers GW et al. Ann Neuro 2006] (Table 2). Table 2. Optimal Definitions for Predicting Poor Outcomes Following Reperfusion.
mRS 5-6 DWI >55 mL and/or PWI Tmax>10s>95mL Sensitivity Specificity PPV NPV 0.27 0.91 0.50 0.78 mRS 3-6 DWI >45 mL and/or PWI Tmax>10s>80mL 0.35 0.92 0.86 0.50
PH2 hemorrhages were 63% versus 20% (p=0.02). Those for median (IQR) infarct growth were 136 mL (92 to 209; n=8) versus 31 mL (5 to 67; n=45; p<0.001). Optimal definitions for predicting poor outcomes following reperfusion are approximately 50 mL for DWI and/or 90 mL for Tmax>10. According to Dr. Mlynash, automated imaging software can prospectively and rapidly identify these patients, improving the efficacy and safety of reperfusion therapies. Whole-Brain Perfusion CT Imaging – A New Method for Mapping Cerebral Vascular Territories Collateral blood supply is believed to be a key determinant of tissue survival in acute stroke. It sustains the penumbra before recanalization and offsets infarct growth [Bang OY et al. Stroke 2011]; yet, its characterization remains elusive. Soren Christensen, PhD, Aarhus University Hospital, Aarhus, Denmark, discussed computed tomography perfusion-based (CTP) Vascular Territory Maps. The hypothesis was that such maps would display redistribution of flow territories that were concordant with CT angiography (CTA). The research entailed a quantitative comparison of territory maps with the CTA-determined site of occlusion. Subjects were 19 acute stroke patients who were imaged <6 hours from symptom onset. Data were acquired on a Toshiba Aquilon One 320 slice system using standard perfusion protocol. Regions of interest (ROI) were placed in the middle cerebral artery, posterior cerebral artery, and anterior cerebral artery. An algorithm tracked the inflow patterns from the ROIs, and the territories were then labeled with colors. Fourteen images were interpretable; 5 were excluded due to head motion and/or poor signal enhancement during the bolus passage. The CTA findings included 2 M1 and 1 internal carotid artery occlusion. In the affected hemisphere, the vascular territory of the occluded vessel was either diminished or absent, with the tissue supplied instead by adjacent territories. In 2 of 14 cases, the estimated collateral territory appeared inconsistent with physiological expectations. According to Dr. Christensen, the initial results are promising. Vascular territory imaging using CTP data would open a window on the importance of the extent and origin of collateral blood supply in acute stroke by quantifying it with a technique that is complementary to standard perfusion and requires no additional hardware or higher radiation doses.
PPV=positive predictive value; NPV=negative predictive value; mRS=modified Rankin Scale; DWI=diffusion weighted imaging; PWI=perfusion weighted imaging.
According to Dr. Mlynash, patients who meet these criteria are likely to have unfavorable outcomes and infarct growth despite endovascular reperfusion. Mlynash et al. [Stroke 2011] found that among patients with a malignant profile who achieved reperfusion following intravenous tPA (n=9), 89% had a Rankin score of 5 to 6 at 90 days versus 39% of patients without reperfusion (n=18; p=0.02). The respective figures for parenchymal hemorrhage were 67% and 11% (p<0.01). The aims of the DEFUSE-2 malignant profile substudy were to investigate whether those who have the malignant profile are more likely to suffer severe disability, parenchymal hemorrhage, infarct growth, or death following endovascular reperfusion and to clarify the optimal definition of the profile in endovascular patients. Clinical response was assessed at 30 and 90 days. Study results show that 0% of malignant profile patients who achieved reperfusion (n=8) had a Rankin score of 0 to 2 at 30 days versus 48% of non-malignant profile patients who reperfused (n=50; p=0.02). The Rankin 5-6 outcomes were 50% in the malignant profile patients versus 22% in the non-malignant group (p=0.19). The respective figures for parenchymal hematoma (PH)1 or
Highlights from the International Stroke Conference 2012
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Table of Contents for the Digital Edition of MD Conference Express ISC 2012
MD Conference Express ISC 2012
From Neurovascular Laboratory to Clinic: A Journey Through Time
No Compelling Evidence to Use Warfarin or Aspirin in Heart Failure Patients
AXIS 2 Clinical Outcomes No Different Than Placebo
SAMMPRIS: 30-Day Outcomes After Angioplasty and Stenting
Aggressive Medical Therapy Benefits Those Who Fail Antithrombotic Therapy
Initial Clinical Results with TREVO® Mechanical Thrombectomy Device are Promising
Linking sICH Definitions to Outcomes
Solitaire™ Flow Restoration Device Achieves Successful Recanalization Free of Symptomatic Hemorrhage Transformation
FIA II Seeks Genetic Underpinnings of Familial Intracranial Aneurysm
SPS3 Study Does Not Support the Use of Combination Therapy for Stroke Prevention
Novel Agent NA-1 Proves that Ischemic Neuroprotection is Possible in Older Patients
Acute Endovascular Treatment
Neuroimaging
Stroke Guidelines: Current Recommendations in Principle and Practice
The Rising Trend of Ischemic Stroke in the Young
Advanced Neuroimaging Adds Time, Reduces Endovascular Treatment in Clinical Practice
MD Conference Express ISC 2012
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