Figure 3

The determinative power of the proportion of ${\mathbf{H}\mathbf{U}}_{\mathbf{17}}^{\mathbf{24}}$ in differentiating severe and mild edema subjects. (A) A non-parametric ROC curve. Area under the curve = 0.85, with asymptotic P = 0.005. The cutoff point was set to 22.58% - giving a sensitivity of 0.82 and a specificity of 0.68. Gray = reference line, black = empirical ROC curve. (B) An error bar chart for comparing mildly edematous subjects and severely edematous subjects in terms of the proportion of pixels with 17 to 24 HU. HU, Hounsfield Unit; ROC, receiver operator characteristics.