**3. Results**

**2.4. Data and statistical analysis**

performance.

128 New Perspectives in Breast Imaging

considered to be statistically significant.

The observers' detection performance was evaluated using receiver operating characteristic (ROC) curve analysis. The confidence level results were used to construct ROC curves. This allowed to obtain the sensitivity, specificity, positive predictive value (PPV), negative predic‐ tive value (NPV), and accuracy of each monitor. Image quality ratings were tabulated for each reader and summarized across all readers. The confidence interval (CI) for the proportion of 4K ratings as similar (0), slightly better (±1), or better (±2) was obtained, considering the side‐by‐side comparison to be a single test condition. In the statistical analysis, differences at *P* < 0.05 were

4K tablet PC 20.8 (inches) 2560 × 3840 Color 300 850:1 UT‐MA6

5‐MP LCD 21.3 (inches) 2048 × 2560 Monochrome 450 800:1 MFGD5621HD

**Figure 2.** Two sets of 4K tablet PCs with high‐resolution color monitors (4K UT‐MA6, 2560 × 3840 pixels, 20.8 inch; Panasonic).

**Table 1.** The physical properties of the 5‐MP LCDs and 4K display monitors used in comparison with observer

**luminance (cd/m2**

**)**

**Contrast ratio Product name** 

**(manufacturer)**

(Panasonic)

(Barco)

**Screen size Matrix size Color Maximum** 

**Table 2** and **Figure 3** show the average under the curve (AUC) values and ROC curves for detection of breast cancers using the 5‐MP LCDs and the 4K tablet PCs, respectively. The mean AUC values for use of the 5‐MP LCDs and the 4K tablet PCs were 0.921 and 0.936, respectively. The difference was not statistically significant (*P* = 0.27). Sensitivity, specificity, positive and negative predictive values, and accuracy were comparable (**Table 3**).


**Table 2.** The area under the ROC curve for the 5‐MP and 4K in BI‐RADS scores.

**Figure 3.** ROC curves for the detection of breast cancers. FPF, false positive fraction; TPF, true positive fraction. The thick line shows the ROC curve for a set of 4K tablet PC with high‐resolution color monitors and the dashed line shows the ROC curve for a set of 5‐MP LCDs. There was no significant difference between the two types of display modes (*P* = 0.27).


**Table 3.** Sensitivity, specificity, positive and negative predictive values and accuracy with the 5‐MP and 4K.

With regard to image quality, brightness for the 4K tablet PC was rated as similar to that of the 5‐MP LCD in 12% of the study readings, slightly better in 54%, and better in 27%. Contrast for the 4K tablet PC was rated as similar to that of the 5‐MP LCD in 26% of the study readings, slightly better in 40%, and better in 15%. Sharpness for the 4K tablet PC was rated as similar to that of the 5‐MP LCD in 38% of the study readings, slightly better in 26%, and better in 12%. Noise for the 4K tablet PC was rated as similar to that of the 5‐MP LCD in 85% of the study readings, and slightly better in 5% (**Table 4** and **Figure 4**). **Figures 5**–**8** demonstrated breast cancers displayed on 5‐MP and 4K monitors.


**Table 4.** Image quality on the basis of brightness, contrast, sharpness and noise, for side‐by‐side feature visibility rating with 5‐MP versus 4K. Values are presented as numbers (also percentages). Mean is average preference by percentage. Positive numbers indicate a preference for 4K and negative numbers indicate a preference for 5‐MP. CL; confidence limits.

**Figure 4.** Likert scale scores (*n* = 100 eligible patients). Image quality on the basis of brightness, contrast, sharpness, and noise, for side‐by‐side feature visibility rating with 4K and 5‐MP LCD. Values are presented as percentages.

Initial Clinical Evaluation of Observer Performance Using a Tablet Computer with a 4K... http://dx.doi.org/10.5772/intechopen.69074 131

**Figure 5.** Microlobulated mass in the left upper area \*captured images.

With regard to image quality, brightness for the 4K tablet PC was rated as similar to that of the 5‐MP LCD in 12% of the study readings, slightly better in 54%, and better in 27%. Contrast for the 4K tablet PC was rated as similar to that of the 5‐MP LCD in 26% of the study readings, slightly better in 40%, and better in 15%. Sharpness for the 4K tablet PC was rated as similar to that of the 5‐MP LCD in 38% of the study readings, slightly better in 26%, and better in 12%. Noise for the 4K tablet PC was rated as similar to that of the 5‐MP LCD in 85% of the study readings, and slightly better in 5% (**Table 4** and **Figure 4**). **Figures 5**–**8** demonstrated breast

**Table 3.** Sensitivity, specificity, positive and negative predictive values and accuracy with the 5‐MP and 4K.

**5‐MP LCD 4K**

Sensitivity 0.857 (0.863/0.956) 0.881 (0.788/0.937) Specificity 0.918 (0.889/0.936) 0.963 (0.939/0.978) PPV 0.735 (0.643/0.794) 0.860 (0.769/0.915) NPV 0.960 (0.931/0.980) 0.969 (0.945/0.984) Accuracy 0.905 (0.860/0.934) 0.946 (0.908/0.969)

cancers displayed on 5‐MP and 4K monitors.

**4K slightly better (+1)**

**Similar (0) 5‐MP** 

**slightly better (−1)**

**Table 4.** Image quality on the basis of brightness, contrast, sharpness and noise, for side‐by‐side feature visibility rating with 5‐MP versus 4K. Values are presented as numbers (also percentages). Mean is average preference by percentage. Positive numbers indicate a preference for 4K and negative numbers indicate a preference for 5‐MP. CL; confidence limits.

**Figure 4.** Likert scale scores (*n* = 100 eligible patients). Image quality on the basis of brightness, contrast, sharpness, and

noise, for side‐by‐side feature visibility rating with 4K and 5‐MP LCD. Values are presented as percentages.

Brightness 27 54 12 7 0 1.00 0.84 1.16 Contrast 15 40 26 19 0 0.51 0.32 0.70 Sharpness 12 26 38 24 0 0.26 0.07 0.45 Noise 0 5 85 10 0 −0.05 −0.13 0.03

**5‐MP better (−2)**

**Mean Lower 95% CL**

**Upper 95% CL**

**4K better (+2)**

130 New Perspectives in Breast Imaging

**Figure 6.** Spiculated mass \*captured images.

**Figure 7.** Finelinear branching calcifications in the left lower area \*captured images.

**Figure 8.** Amorphous grouped calcifications \*captured images.
