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. Author manuscript; available in PMC: 2009 Aug 1.
Published in final edited form as: Ann Neurol. 2008 Aug;64(2):149–157. doi: 10.1002/ana.21424

Table 3. Results of the multivariate analyses considering all "significant" variables from univariate analyses, comparing stroke patients to non-stroke patients (Analysis #1), and infarct side with contralateral side (Analysis #2), and comparison using a ROC analysis.

A ROC analysis allows to assess the "quality" of a model. More specifically, the area under the ROC curve is a measure of the accuracy of the model. A model with a area under the ROC curve equal to 1 is a perfect model, where the predicted values match exactly the observed values; if the area under to ROC curve decreases below 1, this corresponds to the accumulation of false positive and false negative predicted values; finally, if the area under the ROC curve is 0.5, the model is as good in its predictive ability as flipping a coin.

"Carotid Stroke Patients" versus "Non-Carotid Stroke Patients" (Analysis #1) Infarct Side versus Contralateral Side (Analysis #2)
CT features Odds ratio (95% CI) p value CT features Odds ratio (95% CI) p value
Lumen area [mm2] 0.79 (0.71 – 0.88) <0.001
wall volume [100 mm3] 4.08 (2.24 – 7.43) <0.001 wall volume [100 mm3] 1.58 (1.00 – 2.49) 0.017
number of calcium clusters 0.31 (0.15 – 0.63) 0.001 fibrous cap thickness 0.11 (0.06 – 0.16) 0.013
number of lipid clusters 1.22 (1.08 – 1.39) 0.002 number of lipid clusters 1.58 (1.15 – 2.18) 0.005
location of largest lipid cluster 0.74 (0.61 – 0.89) 0.002 location of largest lipid cluster 0.83 (0.67 – 1.02) 0.048
Area under ROC curve = 0.796 Area under ROC curve = 0.832

CI stands for confidence interval