Bijoy Menon MBBS, MD, Abstract Co-Author: Nothing to Disclose

Mayank Goyal MD, FRCPC, Abstract Co-Author: Shareholder, Calgary Scientific, Inc Research grant, Bayer AG

Simerpreet Bal, Abstract Co-Author: Nothing to Disclose

Eric Edward Smith MD, MPH, Abstract Co-Author: Nothing to Disclose

Andrew Demchuk MD, Abstract Co-Author: Nothing to Disclose

Muneer Eesa MBBS, Presenter: Nothing to Disclose

Sung-Il Sohn, Abstract Co-Author: Nothing to Disclose

To derive a CT-angiography based imaging score based on extent of ischemic core, leptomeningeal collaterals and clot burden and determine its ability to discriminate clinical outcomes with or without therapy.

This was a single center study of patients with acute ischemic stroke and M1 MCA+/-intracranial ICA occlusion. Clot burden score (CBS) is a 10 point score assessing extent of clot in the anterior circulation and the rLMC score is a 20 point collateral score based on scoring pial and lenticulostriate arteries in the anterior circulation. Good clinical outcome was defined as modified Rankin Score ≤2 at 90 days. The point scores for the 3C score were assigned based on prior presented multivariable-adjusted analysis. The 3C score (range 0-6) comprises 3 imaging measurements at baseline: 1.CTA-SI ASPECTS categorized (0-4=0 points, 5-7=1, 8-10=2) 2.Collaterals (rLMC score 0-10=0, 11-16=1, 17-20=2) and 3.Clot burden (CBS 0-5=0, 6-7=1, 8-10=2). Primary measure of discrimination of clinical outcome was the c statistic.

There were 133 patients (mean age 66, median NIHSS 16). Figure 1 shows the distribution of good clinical outcome based on the 3C score. The c statistic for the 3C score was 0.75, indicating moderate to good discrimination of good outcomes. By comparison, the c statistic for NCCT ASPECTS was 0.62 and for CTA-SI ASPECTS was 0.66, and for a multivariable model containing age and NIHSS was 0.67. Figure 2 shows the probability of good clinical outcome according to 3C score in subjects receiving any IA therapy. The relationship between 3C score and the probability of a good outcome was similar across all treatment categories.

The 3C score combines information on extent of core, leptomeningeal collaterals and thrombus burden using CTA in patients with acute ischemic strokes caused by MCA occlusion. It is better at discriminating the chance of a good clinical outcome than either NCCT, CTA-SI ASPECTS or the combination of age and NIHSS. Based on these preliminary analyses, the 3C score warrants further validation studies in independent patient cohorts.

The combination of extent of core, leptomeningeal collaterals and thrombus burden using CTA in patients with acute ischemic strokes may be a better tool for patient likely to have a good outcome.

Menon, B, Goyal, M, Bal, S, Smith, E, Demchuk, A, Eesa, M, Sohn, S, The 3C Score: Deriving Optimal CT-based Imaging Characteristics for Predicting Clinical Outcome in Acute Ischemic Strokes with Proximal Occlusions.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11008324.html