Automated identification of cephalometric landmarks: Part 2-Might it be better than human?

Abstract

Objectives: To compare detection patterns of 80 cephalometric landmarks identified by an automated identification system (AI) based on a recently proposed deep-learning method, the You-Only-Look-Once version 3 (YOLOv3), with those identified by human examiners.

Materials and methods: The YOLOv3 algorithm was implemented with custom modifications and trained on 1028 cephalograms. A total of 80 landmarks comprising two vertical reference points and 46 hard tissue and 32 soft tissue landmarks were identified. On the 283 test images, the same 80 landmarks were identified by AI and human examiners twice. Statistical analyses were conducted to detect whether any significant differences between AI and human examiners existed. Influence of image factors on those differences was also investigated.

Results: Upon repeated trials, AI always detected identical positions on each landmark, while the human intraexaminer variability of repeated manual detections demonstrated a detection error of 0.97 ± 1.03 mm. The mean detection error between AI and human was 1.46 ± 2.97 mm. The mean difference between human examiners was 1.50 ± 1.48 mm. In general, comparisons in the detection errors between AI and human examiners were less than 0.9 mm, which did not seem to be clinically significant.

Conclusions: AI showed as accurate an identification of cephalometric landmarks as did human examiners. AI might be a viable option for repeatedly identifying multiple cephalometric landmarks.

Keywords: Artificial intelligence; Automated identification; Cephalometric landmarks; Deep learning; Machine learning.

Figure 1.

Flow diagram summarizing the experimental design.

Figure 2.

Point plots summarizing the mean differences between human examiners and between AI vs humans.

Figure 3.

Scattergrams and 95% confidence ellipses illustrating representative cases. Left: when there is no statistically significant difference between AI and human examiners (Articulare); Right: when human examiners demonstrate a more accurate detection (upper incisal edge).