Mittal, Manoj

Background and Objective Hyperdense middle cerebral artery (HDMCA) sign is an early sign seen on CT head after acute ischemic stroke indicating acute arterial thrombosis. We aimed to measure HDMCA sign objectively. Methods We conducted a retrospective analysis of prospectively collected data from 151 cases of acute ischemic stroke eligible for IV rt-PA by time criteria, admitted to Mayo Clinic from March, 2002 through June, 2011. Admission CT Head was studied to identify HDMCA sign. All patients had either 24 hour CT head or MRI head to confirm the stroke in the same vessel territory. MCA was measured in Hounsfield units and was compared to the contralateral MCA. Receiver Operating Characteristic (ROC) curve analysis was performed to calculate sensitivity and specificity. Results Mean admission NIHSS score was 11±7. HDMCA sign was seen in 93 (62%) patients. ROC curve analysis for ipsilateral MCA Hounsfield units had an area under the curve 0.88 (p<0.001, CI 0.83-0.94) which showed 50 HU or more had 48% sensitivity and 98% specificity. Ratio of ipsilateral to contralateral MCA HU had an area under the curve 0.94 (p<0.001, CI 0.90-0.98) which showed ratio of 1.23 had 67% sensitivity and 98% specificity. A combination of either ipsilateral HU more than equal to 50 or a ratio of ipsilateral to contralateral MCA HU more than equal to 1.23 had 77% sensitivity, 95% specificity, 96% positive predictive value and 72% negative predictive value. Conclusion A combination of ipsilateral HU more than equal to 50 or a ratio of ipsilateral to contralateral MCA HU more than equal to 1.23 can objectively identify HDMCA sign with good sensitivity and high specificity.

Background and Objective Hyperdense MCA (HDMCA) sign is an early sign seen on CT head after acute ischemic stroke indicating acute arterial thrombosis. It has been reported as a predictor of stroke morbidity and mortality. The relationship of size of hyperdense middle cerebral artery (MCA) sign with stroke volume and functional outcome has not been sufficiently studied. Methods We did a retrospective analysis of prospectively collected data from 206 cases of acute ischemic stroke eligible for IV rt-PA by time criteria, admitted to Mayo Clinic from March, 2002 through June, 2011. Admission CT Head was studied to identify HDMCA sign which was further subcategorized according to size. CT head at 24 hours after intravenous tissue plasminogen activator was used to calculate Alberta Stroke Program Early CT Score (ASPECTS) to measure ischemic damage area. Functional outcome was assessed using the modified Rankin score at 3 months and dichotomized into less than equal to 2 (good outcome) and more than 2 (bad outcome). Univariate analysis including t-test, Chi-square, and Fisher Exact test was used when appropriate. Results Mean admission NIHSS score was 11±7. HDMCA sign was seen in 99 (48%) patients: 100% MCA occlusion (7) 76-100% M1 (17), 50-75% M1 (17), less than 50% M1 (6), MCA dot sign (23), sylvian dot sign (21) and sylvian MCA sign, defined as any sylvian MCA occlusion bigger than a dot (8). Univariate analysis showed statistically significant associations between our HDMCA classification and ASPECTS at 24 hours (p<0.001) and modified Rankin score at 3 months (p<0.001). Smaller infarctions (ASPECTS >8) were observed more often with lower MCA clot burden; MCA dot (48%), less than 50% MCA (80%), sylvian dot (57%) and sylvian MCA (38%), 50-75% M1 (6%), 75-100% M1 (0%) and 100% MCA (0%). Good outcome (mRS≤2 at 3 months) was seen more often with lower MCA clot burden; MCA dot (52%), less than 50% MCA (67%), sylvian dot (67%) and sylvian MCA (63%). Conversely, larger HDMCA size was associated with poor outcome (mRS>2); 50-75% M1 (100%), 75-100% (88%) and 100% MCA (100%). Conclusion The size of the HDMCA sign size is an important predictor of ischemic stroke mortality and morbidity. HDMCA should be measured upon admission as it may help refine prognostication and identify patients who could benefit from endovascular rescue therapy after intravenous thrombolysis.

Background and Objective The Alberta Stroke Program Early CT Score (ASPECTS) is a validated grading system to assess ischemic changes on CT in acute ischemic stroke. Magnetic resonance imaging with diffusion weighted imaging (DWI) sequence is commonly used to identify the final ischemic changes. We examined the difference between the relationship of NIHSS at admission and ASPECT score calculated using CT scan versus MRI DWI sequence. Methods We conducted a retrospective analysis of prospectively collected data from 99 cases of acute ischemic stroke treated with IV rt-PA by time criteria, admitted to Mayo Clinic from March, 2002 through June, 2011. CT head at 24 hours and MRI DWI sequence were used to assign ASPECT score. We dichotomized ASPECTS (categorized as 0 to 7 versus 8 to 10) and favorable patient outcome at 3 month (modified Rankin score less than equal to 2 and more than 2). Univariate analysis including t-test, Chi-square, and Fisher Exact test was used when appropriate. Results Mean age was 70±14 years. Mean admission NIHSS score was 8±4. DWI ASPECTS (p<0.001) and CT ASPECTS (p=0.127) were inversely associated with admission NIHSS. Higher (8-10) CT ASPECTS (p=0.001) or DWI ASPECTS (p=0.002) were associated with good outcome (mRS ≤2) at 3 months. Sensitivity, specificity, positive predictive value and negative predictive value for good outcome identified by CT ASPECTS versus DWI ASPECTS were 81% vs 52%, 54% vs 54%, 83% vs 59% and 50% vs 47% respectively. Conclusion CT and MRI DWI are comparably useful to calculate the ASPECTS for estimation of functional outcome, but CT scan at 24 hours may be more sensitive for the prediction of good recovery.

INTRODUCTION After aneurysm treatment, patients with subarachnoid hemorrhage (SAH) are typically kept in the intensive care unit (ICU) to be monitored for signs of delayed cerebral ischemia (DCI). Identifying patients at very low risk of developing this complication who could be safely transferred out of the ICU early could have a very positive financial impact. METHOD We analyzed 307 consecutive patients admitted to the intensive care unit from October 2001 to June 2011. Demographic, clinical and neuroimaging data were recorded. The relationship between these variables and absent DCI was analyzed using univariate and multivariate logistic regression models. RESULTS DCI did not develop in 169 patients (57.9%). Among factors at admission, age ≥ 68 years (p=0.0003; OR 3.16, 95% CI 1.67-6.39), WFNS I-III at presentation (p= 0.0003;OR 2.73, 95% CI 1.57-4.79), WFNS I-III at worst (p= 0.0003; OR 2.39, 95% CI 1.48-3.87), WFNS I-III post resuscitation (p= 0.0006; OR 2.85 95% 1.56-5.32), modified Fisher grade 1-2 (p= 0.0021; OR 2.43, 95% CI 1.37-4.47), absence of intracranial hematoma (p= 0.0042; OR 2.26, 95% CI 1.29-4.01), absence of intraventricular hematoma (p=0.045; OR 1.61, 95% CI 1.01-2.58), absence of cerebrospinal fluid diversion (p= 0.0002; OR 2.54, 95% CI 1.56-4.20) and aneurysm in the posterior circulation (p=0.0253; OR 1.74, 95% CI 1.07-2.87) were associated with absence of DCI. On multivariate analysis, a model including age ≥ 68 years (p= 0.0003; OR 3.23, 95% CI 1.68-6.62), WFNS at presentation I-III (p= 0.0092; OR 2.18, 95% CI 1.21-3.99) and modified Fisher grade 1-2 (p=0.02; OR 2.04, 95% CI 1.11-3.89) was independently uniformly predictive of the absence of DCI (specificity and positive predictive value of 100%; p<0.0001). CONCLUSION We propose a new model that can reliably identify a group of patients with aneurysmal SAH who have very low risk of developing DCI. These patients could be candidates for early transfer to the general ward after treatment of the ruptured aneurysm.