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

Abstract

Objective: A privately owned, 4-year-old female Showa koi (ornamental variant of Common Carp Cyprinus carpio) was presented for erratic swimming, air gasping, water spitting, and abnormal orientation in the water column. Initial physical examination revealed an obese patient with no external abnormalities except a small plaque localized to filaments on a right gill hemibranch. Methods:The fish was anesthetized using AQUI-S 20E (10% eugenol solution) at 50 mg/L to facilitate diagnostic evaluation. Biopsy of the gill lesion yielded no significant findings. Whole-body computed tomography confirmed an excess of adipose tissue and mild scoliosis, with narrowing of the 10th-11th intervertebral space. A weight loss plan and need for repeat assessment were recommended.Result: The patient's original abnormal behaviors resolved over the following weeks, but it subsequently became hyporexic and depressed. Full-body magnetic resonance imaging (MRI) showed extensive alteration of vertebral centra, with multifocal compression of the spinal cord. Due to the patient's declining clinical condition and the grave prognosis based on MRI findings, the patient was humanely euthanized. Conclusion:Postmortem examination showed severe transmural myelomalacia associated with a vertebral subluxation. This case demonstrates the practical application of advanced cross-sectional imaging that has not been commonly afforded to fish or other lower vertebrates.

Magnetic resonance imaging shows spinal curvature in Chinook salmon (Oncorhynchus tshawytscha) is associated with chronic inflammation of peri‐vertebral soft tissues

“…Torpy et al. (2023) recently demonstrated that both MRI and CT imaging can be used to diagnose musculoskeletal ailments in large live fish – in their case a 13 kg Showa koi ( Cyprinus carpio ) with a spinal injury involving vertebral subluxation and associated spinal cord myelomalacia (softening). While future technological advancements are required to make MRI more accessible and user friendly (i.e., portability), it is nevertheless a valuable tool for the future investigation of finfish musculoskeletal health and conditions, including spinal curvature.…”

“…Although MRI has been conducted on finfish previously (e.g., Bock, Sartoris & Pörtner, 2002; Bock, Sartoris, Wittig, et al., 2002; Collewet et al., 2013; Howell et al., 1996; Lannig et al., 2004; Mark et al., 2002; Pörtner et al., 2004; Rogers et al., 2008; Simões et al., 2012; Van der Linden et al., 2004; Wu et al., 2015), including for the purposes of diagnosing musculoskeletal pathology (Torpy et al., 2023), it has not yet been applied to the diagnosis of musculoskeletal pathology in commercially farmed finfish. The aim of the current study was to use MRI to assess peri‐vertebral soft‐tissue pathology in farmed New Zealand Chinook salmon and, in conjunction with histology, evaluate its association with spinal curvature.…”

“…Small lesions could therefore have gone undetected. Alternately, some of the regions without pathologic hyper-intense MRI signal were found to have histological lesions, suggesting that these may have been true lesions that simply were not significant enough to produce a signal on MRI.The observed associations between curvature and inflammatory and fibrotic lesions detected on MRI scans provide evidence that soft-tissue pathology is directly associated with the development of spinal curvature, and may be related to a mechanical loading issue.Further investigation is therefore required to evaluate a possible mechanical aetiology Torpy et al (2023). recently demonstrated that both MRI and CT imaging can be used to diagnose musculoskeletal ailments in large live fish -in their case a 13 kg Showa koi (Cyprinus carpio) with a spinal injury involving vertebral subluxation and associated spinal cord myelomalacia (softening).…”