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Measures of cardiac function in Theraphosidae spiders using in vivo magnetic resonance imaging |
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| Authors: | Gavin D. Merrifield Nichola M. Brydges Lynsey Hall James Mullin Lindsay Gallagher Romain Pizzi William M. Holmes |
| Affiliation: | 1. Glasgow Experimental Magnetic Resonance Imaging Centre, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, U.K.;2. Neurosciences & Mental Health Research Institute, School of Medicine, Cardiff University, Cardiff, U.K.;3. Institute of Psychological Medicine and Clinical Neurosciences, School of Medicine, Cardiff University, Cardiff, U.K.;4. Royal Zoological Society of Scotland, Edinburgh, U.K.;5. School of Veterinary Medicine and Science, University of Nottingham, Nottingham, U.K. |
| Abstract: | We report the first in vivo cardiac magnetic resonance imaging (MRI) measurements of Theraphosidae spiders. MRI scanning is performed on six spiders under isoflurane‐induced anaesthesia. Retrospective self‐gating cine‐cardiac MRI (RG‐CINE‐MRI) is used to overcome the difficulties of prospective cardiac gating in this species. The resulting RG‐CINE‐MRI images are successfully analyzed to obtain functional cardiac parameters from live spiders at rest. Cardiac ejection fraction is found to increase with animal mass (Pearson correlation 0.849, P = 0.03) at a faster rate than myocardial tissue volume, whereas heart rate remains constant across animals. This suggests the spider heart undergoes additional biomechanical loading with age. The results of the present study demonstrate the potential for retrospective gating with respect to evaluating aspects of cardiac function in a wide range of previously inaccessible species. |
| Keywords: | Cardiac function ejection fraction heart rate in vivo magnetic resonance MRI tarantula Theraphosidae |