Figure 4

The determinative power of ${\mathbf{H}\mathbf{U}}_{\mathbf{17}}^{\mathbf{24}}$ in differentiating delayed edema subjects and mild edema subjects. (A) A non-parametric ROC curve. Area under the curve = 0.75, with asymptotic P <0.03. The cutoff point was set to 16.29% - giving a sensitivity of 0.88 and a specificity of 0.68. Gray = reference line, black = empirical ROC curve. (B) An error bar chart depicting the proportion of pixels with 17 to 24 HU in CT images from three subject groups. Mildly = mild edema subjects. Severely = subjects with severe cerebral edema confirmed by initial CT examination. Delayed = subjects who developed delayed cerebral edema. CT, computed tomography; HU, Hounsfield Unit; ROC, receiver operator characteristics.