DAO 91:243-256 (2010)  -  DOI: https://doi.org/10.3354/dao02259

Magnetic resonance imaging quality and volumes of brain structures from live and postmortem imaging of California sea lions with clinical signs of domoic acid toxicosis

Eric W. Montie1,2,*, Elizabeth Wheeler2, Nicola Pussini2, Thomas W. K. Battey3, Jerome Barakos4, Sophie Dennison2, Kathleen Colegrove5, Frances Gulland2

1College of Marine Science, University of South Florida, Florida 33701, USA
2Veterinary Science Department, The Marine Mammal Center, Sausalito, California 94965, USA
3Eckerd College, Galbraith Marine Science Center, St. Petersburg, Florida 33711, USA
4California Pacific Medical Center, University of California, San Francisco, California 94143, USA
5Zoological Pathology Program, College of Veterinary Medicine at Urbana-Champaign, Maywood, Illinois 60153, USA

ABSTRACT: Our goal in this study was to compare magnetic resonance images and volumes of brain structures obtained alive versus postmortem of California sea lions Zalophus californianus exhibiting clinical signs of domoic acid (DA) toxicosis and those exhibiting normal behavior. Proton density- (PD) and T2-weighted images of postmortem-intact brains, up to 48 h after death, provided similar quality to images acquired from live sea lions. Volumes of gray matter (GM) and white matter (WM) of the cerebral hemispheres were similar to volumes calculated from images acquired when the sea lions were alive. However, cerebrospinal fluid (CSF) volumes decreased due to leakage. Hippocampal volumes from postmortem-intact images were useful for diagnosing unilateral and bilateral atrophy, consequences of DA toxicosis. These volumes were similar to the volumes in the live sea lion studies, up to 48 h postmortem. Imaging formalin-fixed brains provided some information on brain structure; however, images of the hippocampus and surrounding structures were of poorer quality compared to the images acquired alive and postmortem-intact. Despite these issues, volumes of cerebral GM and WM, as well as the hippocampus, were similar to volumes calculated from images of live sea lions and sufficient to diagnose hippocampal atrophy. Thus, postmortem MRI scanning (either intact or formalin-fixed) with volumetric analysis can be used to investigate the acute, chronic and possible developmental effects of DA on the brain of California sea lions.


KEY WORDS: Domoic acid · California sea lion · Magnetic resonance imaging · MRI · Brain · Hippocampus · Marine mammal


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Cite this article as: Montie EW, Wheeler E, Pussini N, Battey TWK and others (2010) Magnetic resonance imaging quality and volumes of brain structures from live and postmortem imaging of California sea lions with clinical signs of domoic acid toxicosis. Dis Aquat Org 91:243-256. https://doi.org/10.3354/dao02259

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