## 3 Results  
The sensitivity of the CNN thrombus detection was 0.86, vs. 0.95 and 0.79 for neuroradiologist 1 and 2 respectively (Table 1). Specificity was 0.65 for the network vs. 0.58 and 0.82 for the neuroradiologists. Precision was 0.75, 0.74 and 0.81 for the CNN, neuroradiologist 1 and neuroradiologist 2, respectively. The CNN correctly identified the location of the thrombus in 79% of the cases, compared to 81% and 77% for the neuroradiologists. An example of the results is given in Figure 2. The agreement in thrombus volume was fair (ICC: 0.49) for the CNN, poor for neuroradiologist 1 (ICC: 0.37) and fair for neuroradiologist 2 (ICC: 0.55). For the thrombus density, the ICC was poor (ICC: 0.14) for the CNN and fair for neuroradiologist 1 and 2 (ICC: 0.45 and ICC: 0.40, respectively). The scatter and Bland-Altman plots for the segmented thrombus volumes and for the thrombus density are shown in Figures 3 and 4, respectively. The scatter plots show the relation of the thrombus volumes and densities that were computed from the thrombus segmentations by one of the neuroradiologists or CNN and those of the ground truth. The diagonal line within the scatter plots, represent the perfect match of the results between the neuroradiologists or CNN and ground truth. The Bland-Altman plots show the difference in measurements, comparing the results of the neuroradiologists or CNN with the ground truth. The mean and standard deviation of the differences are also shown within the plots, represented as bias and limits of agreements. The exact values of the bias and limits of agreements for thrombus volume and density, together with the other results are shown in Table 1.  
\begin{table}
\begin{tabular}{c c c c} \hline  & **CNN** & **Neuroradiologist 1** & **Neuroradiologist 2** \\ \hline
**Sensitivity** & 0.86 & 0.93 & 0.78 \\ \hline
**Specificity** & 0.69 & 0.60 & 0.88 \\ \hline
**Precision** & 0.75 & 0.74 & 0.82 \\ \hline
**Correct thrombus location** & 0.79 & 0.81 & 0.77 \\ \hline \multicolumn{4}{c}{**Thrombus Volume**} \\ \hline
**ICC** & 0.49 (95\% CI: 0.27 to 0.66) & 0.37 (95\% CI: 0.42 to 0.75) & 0.55 (95\% CI: 0.29 to 0.72) \\ \hline
**Bias (mm3)** & 73 & \(-\)58.6 & \(-\)91.5 \\ \hline
**LoA (mm3)** & \(-\)447/593 & \(-\)427/309 & \(-\)453/269 \\ \hline \multicolumn{4}{c}{**Thrombus Density**} \\ \hline
**ICC** & 0.14 (95\% CI: -0.12 to 0.41) & 0.45 (95\% CI: 0.07 to 0.70) & 0.40 (95\% CI: 0.07 to 0.64) \\ \hline
**Bias (HU)** & \(-\)4.6 (4.8) & 3.8 & 2.8 \\ \hline
**LoA (HU)** & \(-\)18/9 & \(-\)7/14 & \(-\)7/13 \\ \hline \end{tabular}
\end{table}
Table 1: Test results from the CNN, neuroradiologist 1 and neuroradiologist 2. The table shows sensitivity, specificity, correct thrombus location assessment rate and the intraclass correlation coefficient (ICC) with bias and limits of agreements (LoA) for both thrombus volume and density.  
Figure 2: An example of the segmentation results. (**A**) Original non-contrast computed tomography (NCCT); (**B**) Segmentation made by one of the neuroradiologists; (**C**) Segmentation acquired by the CNN.  
Figure 3: Scatter (**Left**) and Bland–Altman plots (**Right**) for thrombus volumes. The dotted line and dashed lines within the Bland–Altman plot represent the bias and limits of agreements, respectively.  
Figure 4: Scatter (**Left**) and Bland–Altman (**Right**) plots for thrombus density. The dotted line and dashed lines within the Bland–Altman plot represent the bias and limits of agreements, respectively.