Cross-sectional anatomy, computed tomography, and magnetic resonance imaging of the banded houndshark (Triakis scyllium)

Abstract

Due to their important phylogenetic position among extant vertebrates, sharks are an invaluable group in evolutionary developmental biology studies. A thorough understanding of shark anatomy is essential to facilitate these studies and documentation of this iconic taxon. With the increasing availability of cross-sectional imaging techniques, the complicated anatomy of both cartilaginous and soft tissues can be analyzed non-invasively, quickly, and accurately. The aim of this study is to provide a detailed anatomical description of the normal banded houndshark (Triakis scyllium) using computed tomography (CT) and magnetic resonance imaging (MRI) along with cryosection images. Three banded houndsharks were scanned using a 64-detector row spiral CT scanner and a 3 T MRI scanner. All images were digitally stored and assessed using open-source Digital Imaging and Communications in Medicine viewer software in the transverse, sagittal, and dorsal dimensions. The banded houndshark cadavers were then cryosectioned at approximately 1-cm intervals. Corresponding transverse cryosection images were chosen to identify the best anatomical correlations for transverse CT and MRI images. The resulting images provided excellent detail of the major anatomical structures of the banded houndshark. The illustrations in the present study could be considered as a useful reference for interpretation of normal and pathological imaging studies of sharks.

Interactive three-dimensional atlas of the mineralized skeleton of the sand tiger shark Carcharias taurus

“…Other studies have pursued similar endeavours of providing anatomical studies aided by modern imaging techniques [ 36 , 37 ], but, to our knowledge, none of these have included three-dimensional or otherwise interactive representations. One noteworthy online resource for chondrichthyan anatomy is the website ‘Chondrichthyan Tree of Life’ [ 38 ] which, among other things, offers an impressive selection of less in-depth segmented anatomical models than the one presented in this article.…”

Use of computed tomography and magnetic resonance imaging to assess a case of spinal injury in a Showa koi Cyprinus carpio

“…In research contexts, however, MRI of live fish has already been successfully implemented in a number of species (Wu et al 2015; Koth et al 2017). The MRI characterization of normal anatomy in koi, as well as other aquatic species, has already begun to be established, which further increases the utility of the modality (Kalat and Shabanipour 2010; Ziegler et al 2011; Kim et al 2021). To our knowledge, there are no prior reports of MRI usage as an ante‐mortem diagnostic for fish in a clinical setting.…”

Contrast‐enhanced computed tomography and cross‐sectional anatomy of the trunk in the brownbanded bamboo shark (Chiloscyllium punctatum)

“…Many studies conducted to date in aquatic animals, such as various dolphins (Alonso‐Farré et al, 2014, 2015; Ivančić et al, 2014), California sea lion Zalophus californianus (Dennison & Schwarz, 2008), Loggerhead sea turtle Caretta caretta (Valente et al, 2007), and Pacu Colossoma macroponum (Carr et al, 2014), have compared anatomical cross‐sections and CT images. With regard to Selachimorpha, Kim et al (2021) reported the use of NCCT and MRI to study the cadavers of Banded houndshark Triakis scyllium for the purpose of the normal anatomy reference. These authors reported that from the NCCT images of soft tissues, it was difficult to identify the adjacent organs because of low contrast, although sufficient images were obtained by MRI scan.…”