Accuracy and reliability of cetacean cranial measurements using computed tomography three dimensional volume rendered images

Adams Hei Long Yuen; Henry Chun Lok Tsui; Brian Chin Wing Kot

doi:10.1371/journal.pone.0174215

Accuracy and reliability of cetacean cranial measurements using computed tomography three dimensional volume rendered images

PLoS One. 2017 Mar 22;12(3):e0174215. doi: 10.1371/journal.pone.0174215. eCollection 2017.

Authors

Adams Hei Long Yuen¹, Henry Chun Lok Tsui¹, Brian Chin Wing Kot^{1

2}

Affiliations

¹ School of Medical and Health Sciences, Tung Wah College, Homantin, Kowloon, Hong Kong SAR, China.
² Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong SAR, China.

Abstract

Computed tomography (CT) has become more readily available for post-mortem examination, offering an alternative to cetacean cranial measurements obtained manually. Measurement error may result in possible variation in cranial morphometric analysis. This study aimed to evaluate the accuracy and reliability of cetacean cranial measurements obtained by CT three-dimensional volume rendered images (3DVRI). CT scans of 9 stranded cetaceans were performed. The acquired images were reconstructed using bone reconstruction algorithms. The reconstructed crania obtained by 3DVRI were visualized after excluding other body structures. Accuracy of cranial measurements obtained by CT 3DVRI was evaluated by comparing with that obtained by manual approach as standard of reference. Reproducibility and repeatability of cranial measurements obtained by CT 3DVRI were evaluated using intraclass correlation coefficient (ICC). The results demonstrated that cranial measurements obtained by CT 3DVRI yielded high accuracy (88.05%- 99.64%). High reproducibility (ICC ranged from 0.897 to 1.000) and repeatability (ICC ranged from 0.919 to 1.000 for operator 1 and ICC range from 0.768 to 1.000 for operator 2) were observed in cranial measurements obtained by CT 3DVRI. Therefore, cranial measurements obtained by CT 3DVRI could be considered as virtual alternative to conventional manual approach. This may help the development of a normative reference for current cranial maturity and discriminant analysis studies in cetaceans.

MeSH terms

Algorithms
Animals
Autopsy / methods
Bone and Bones / anatomy & histology
Cetacea / anatomy & histology*
Discriminant Analysis
Humans
Imaging, Three-Dimensional / methods
Observer Variation
Reproducibility of Results
Skull / anatomy & histology
Tomography, X-Ray Computed / methods

Grants and funding

This project was financially supported by the Hong Kong Research Grants Council [Grant number: UGC/FDS17/M07/14] and received by BK. URL: http://www.ugc.edu.hk/eng/rgc/result/sf/fds1415_abstract.htm#FDS17M07. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.