Prehensile and non-prehensile tails among syngnathid fishes: what’s the difference?

All syngnathid fishes are characterized by a tail with a vertebral column that is surrounded by dermal Plates - four per vertebra. Seahorses and pipehorses have prehensile tails, a unique characteristic among teleosts that allows them to grasp and hold onto substrates. Pipefishes, in contrast, possess a more rigid tail. Previous research (Neutens et al., 2014) showed a wide range of variation within the skeletal morphology of different members in the syngnathid family. The goal of this study is to explore whether the diversity in the three-dimensional (3D) shape of different tail types reflects grasping performance, and to what degree grasping tails occupy a different and more constrained diversity. For this, a 3D morphometrical analysis based on surfaces was performed. Four different analyses were performed on the tail skeleton of nine species exhibiting different levels of tail grasping capacities (four pipehorse, three seahorse, one pipefish and one seadragon species) to examine the intra-individual variation across the anteroposterior and dorso-ventral axis. In the two interspecific analyses, all vertebrae and all dermal plates were mutually compared. Overall, intra-individual variation was larger in species with a prehensile tail. The analysis on the vertebrae showed differences in the length and orientation of the hemal spine as well as the inclination angle between the anterior and posterior surface of the vertebral body. This was observed at an intra-individual level across the anteroposterior axis in prehensile species and at an inter-individual level between prehensile and non-prehensile species. Across the anteroposterior axis in prehensile tails, the overall shape of the plates changes from rectangular at the anterior end to square at the posterior end. Across the dorso-ventral axis, the ventral dermal plates carry a significantly longer caudal spine than the dorsal ones in all prehensile-tailed species. It can therefore be concluded that prehensile tails exhibit a larger anteroposterior and dorso-ventral shape variation than non-prehensile ones. However, the hypothesis that there is a more constrained shape variation among prehensile species compared to non-prehensile ones had to be rejected.Neutens C., de Dobbelaer B., Claes P., Adriaens D., ''Prehensile and non-prehensile tails among syngnathid fishes: what’s the difference?'', Zoology, vol. 120, pp. 62-72, February 2017.status: publishe

3D surface-based morphometrics used to determine the intraspecific differences within the tail of syngnathid fishes

Neutens C., De Dobbelaer B., Claes P., Adriaens D., ''3D surface-based morphometrics used to determine the intraspecific differences within the tail of syngnathid fishes'', Integrative and comparative biology, vol. 55, pp. E133, 2015 (The Society for Integrative and Comparative Biology annual meeting - SICB 2015, January 3-7, 2015, West Palm Beach, Florida, USA).status: publishe

Segmentation of liver metastases using a level set method with spiral-scanning technique and supervised fuzzy pixel classification

In this paper a specific method is presented to facilitate the semi-automatic segmentation of liver metastases in CT images. Accurate and reliable segmentation of tumors is e.g. essential for the follow-up of cancer treatment. The core of the algorithm is a level set function. The initialization is provided by a spiral-scanning technique based on dynamic programming. The level set evolves according to a speed image that is the result of a statistical pixel classification algorithm with supervised learning. This method is tested on CT images of the abdomen and compared with manual delineations of liver tumors. The results show that the accuracy of the method does not reach that of the manual segmentation. The average overlap error is 34.6% and the average volume difference is 17.8%. The average, the rms and the maximum surface are respectively 2.0, 2.7 and 10.1 mm.Smeets D., Stijnen B., Loeckx D., De Dobbelaer B., Suetens P., ''Segmentation of liver metastases using a level set method with spiral-scanning technique and supervised fuzzy pixel classification'', Workshop proceedings of the 11th international conference on medical image computing and computer assisted intervention - MICCAI 2008, workshop on 3D segmentation in the clinic : a grand challenge II, September 6, 2008, New York, USA.status: publishe

Semi-automatic level set segmentation of liver tumors combining a spiral scanning technique with supervised fuzzy pixel classification

In this paper, a specific method is presented to facilitate the semi-automatic segmentation of liver tumors and liver metastases in CT images. Accurate and reliable segmentation of tumors is essential for the follow-up of cancer treatment. The core of the algorithm is a level set method. The initialization is generated by a spiral-scanning technique based on dynamic programming. The level set evolves according to a speed image that is the result of a statistical pixel classification algorithm with supervised learning. This method is tested on CT images of the abdomen and compared with manual delineations of liver tumors. The described method outperformed the semi-automatic methods of the other participants of the "3D Liver Tumor Segmentation Challenge 2008". Evaluating the algorithm on the provided test data leads to an average overlap error of 32.6% and an average volume difference of 17.9%. The average, the RMS and the maximum surface distance are 2.0, 2.6 and 10.1 mm, respectively.Smeets D., Loeckx D., Stijnen B., De Dobbelaer B., Vandermeulen D., Suetens P., ''Semi-automatic level set segmentation of liver tumors combining a spiral scanning technique with supervised fuzzy pixel classification'', Medical image analysis, vol. 14, no. 1, pp. 13-20, February 2010.status: publishe

Semi-automated digital bullet trajectory reconstruction in craniofacial ballistic trauma

Develter W., Wuestenbergs J., Van de Voorde W., Coudyzer W., De Dobbelaer B., Vandermeulen D., Snyders J., ''Semi-automated digital bullet trajectory reconstruction in craniofacial ballistic trauma'', Journal of forensic radiology and imaging, vol. 1, no. 2, pp. 83, April 2013 (2nd congress of the International Society of Forensic Radiology and Imaging - ISFRI 2013, May 13-14, 2013, Zurich, Switzerland).status: publishe

Automated quantification of adipose tissue in whole body small-animal micro MRI images

Loeckx D., Dresselaers T., Hemmeryckx B., De Dobbelaer B., Maes F., Lijnen H.R., Suetens P., ''Automated quantification of adipose tissue in whole body small-animal micro MRI images'', 9th Belgian day on biomedical engineering, November 26, 2010, Brussels, Belgium.status: publishe

Automated quantification of adipose tissue in whole body small-animal micro MRI images

Loeckx D., Dresselaers T., Hemmeryckx B., De Dobbelaer B., Maes F., Lijnen H.R., Himmelreich U., Suetens P., ''Automated quantification of adipose tissue in whole body small-animal micro MRI images'', World molecular imaging congress - WMIC 2010, September 8-11, 2010, Kyoto, Japan.status: publishe

The feasibility of measuring body weight on CT images and the first steps in anatomical mirroring

Wuestenbergs J., Coudyzer W., De Dobbelaer B., Develter W., Joris P., Claes P., Vandermeulen D., Jenar E., Geusens E., Van de Voorde W., ''The feasibility of measuring body weight on CT images and the first steps in anatomical mirroring'', Journal of forensic radiology and imaging, vol. 2, no. 2, pp. 105, April 2014 (3rd congress of the International Society of Forensic Radiology and Imaging - ISFRI 2014, May 15-17, 2014, Marseille, France).status: publishe