# Real-Time Multi-Label Upper Gastrointestinal Anatomy Recognition from Gastroscope Videos
## 3 Results
### Experimental Results
#### 3.2.3 Retrospective Analysis of EGD Videos  
Based on the methodology proposed in this paper, we designed a framework for statistical analysis of the examination quality of real EGD videos in hospitals according to quality monitoring guidelines. We collected a total of 1736 EGD videos, all of which were captured with an OLYMPUS EVIS LUCERA ELITE CLV-290 SL at 25 FPS and operated by  
Figure 8: The prediction results on the video clips of ResNet-GCN and GL-Net. The bottom of each line corresponds to the results of ResNet-GCN, GL-Net and Ground Truth (GT) annotations separately. Specifically, 0-esophagus, 1-squamocolumnar junction, 3-outside of cardia, 9-greater curvature of lower body, 13-greater curvature of Antrum, 14-posterior wall of Antrum, 15-anterior wall of Antrum, 17-angulus, 22-duodenal bulb, 24-pylorus. expert physicians. In addition to the anatomical position identification model proposed in this paper, our system uses an invalid frame filtering model [55] to ensure that our statistical results are performed on clear and valid images. The outputs of the proposed system are: (1) coverage statistics of the 25 sites observed; (2) total examination time; (3) examination time for each specific site; (4) the ratio of valid frames versus invalid frames. The average coverage of anatomical structures during the EGD produced by the endoscopist was 85.81%, but only 19.28% of the patients were not blinded. In addition, the rate of misses for each anatomical structure (total number of videos with undetected anatomical structures/total number of videos) can be seen in Table 3. It can be clearly seen that most of the anatomical structures had a probability of being missed, except for the esophagus. Among them, the lower body lesser curvature had the highest miss rate of 52.41%, indicating that this area tends to be a blind area in EGD surgery. In addition, the small curvature of the middle and upper body, the descending duodenum, the posterior wall of the lower body, and the large curvature of the middle and upper body also had a blind spot rate of more than 20% in the retrograde view. As shown in Table 4, the mean examination time for all the videos was 6.572 min, but the variance is quite different, which may be because some videos take biopsies or make abnormal findings. Considering that there were some blind spots in the process of EGD, we further analysed the inspection time when 25 sites were completely observed. As can be seen, it takes 7.37 min for endoscopists to check all the anatomical structures. \begin{table}
\begin{tabular}{l c} \hline \hline
**Anatomy** & **Miss Rate (\%)** \\ \hline esophagus & 0.00 \\ Squamocolumnar & 0.60 \\ junction & 10.24 \\ Cardia O & 0.6 \\ Fundus & 9.04 \\ Middle-upper body A & 7.83 \\ Middle-upper body L & 10.24 \\ Middle-upper body P & 15.06 \\ Middle-upper body G & 43.98 \\ Lower body A & 13.86 \\ Lower body L & 23.49 \\ Lower body P & 18.67 \\ Lower body G & **52.41** \\ Antrum A & 9.64 \\ Antrum L & 13.25 \\ Antrum P & 11.45 \\ Antrum G & 9.64 \\ Angulus & 6.05 \\ R-middle-upper body A & 22.89 \\ R-middle-upper body L & 13.86 \\ R-middle-upper body P & 10.24 \\ R-middle-upper body G & 15.06 \\ Duodenal bulb & 5.42 \\ Duodenal descending & 24.70 \\ Pylorus & 6.63 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: The average miss rate of each UGI anatomical structure during EGD. Bold indicates the maximum value. Table 5 shows the examination time of each specific anatomical structure. Obviously, the most time-consuming site is the esophagus, which takes 85.8 s, far more than the other 24 sites. However, the endoscopists spend the least time in the lower gastric body, and the average observation time of the lesser curvature of lower body is only 1.8 s.  
In addition, although no studies have clearly defined the effective time of endoscopists in operation, the visibility of mucosa has become an important indicator in the quality control guidelines of colonoscopy.