Hippocampal sclerosis is the most common imaging finding of intractable human epilepsy, and it may play an important role in canine and feline epileptogenesis and seizure semiology, too. The magnetic resonance imaging (MRI) criteria of hippocampal sclerosis are T2 hyperintensity, shrinkage and loss of internal structure. The detection of these changes is often challenging by subjective visual assessment of qualitative magnetic resonance (MR) images. The recognition is more reliable with quantitative MR methods, such as T2 relaxometry. In the present prospective study including 31 dogs with idiopathic epilepsy and 15 control dogs showing no seizure activity, we compared the T2 relaxation times of different brain areas. Furthermore, we studied correlations between the hippocampal T2 values and age, gender and skull formation. We found higher hippocampal T2 values in the epileptic group than in the control; however, these findings were not statistically significant. No correlations were found with age, gender or skull formation. In the individual analysis six epileptic dogs presented higher hippocampal T2 relaxation times than the cut-off value. Two of these dogs were also evaluated as abnormal in the visual assessment. Individual analysis of hippocampal T2 relaxation times may be a helpful method to understand hippocampal involvement in canine epilepsy. Key words: Canine, epilepsy, hippocampus, MRI, T2 relaxometryThe hippocampus, located in the medial temporal lobe of the forebrain belonging to the limbic system, plays an important role in human epilepsy. On one * Corresponding author; E-mail: Borbala.Loerincz@vetmeduni.ac.at; Phone: 0043 (664) 60257-6460; Fax: 0043 (1) This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium for non-commercial purposes, provided the original author and source are credited.
Despite numerous studies on cerebrospinal fluid (CSF) and its importance during hydrocephalus or myelography, no reliable values exist about its overall volume in dogs. In this study, our aim was to measure the intracranial (IC) volume of CSF in dogs and assess its possible relationship with body size and the symmetry of the lateral ventricles. We ran a 3D magnetic resonance imaging (MRI) sequence on the central nervous system of 12 healthy, male mongrel dogs between 3-5 years of age and 7.5-35.0 kg body weight. A validated semiautomatic segmentation protocol was implemented to segment the CSF and measure its volume. Values for the volume of the ventricular compartment were between 0.97 and 2.94 ml, with 62.1 ± 11.7% in the lateral ventricles, 17.6 ± 4.9% in the third ventricle, 4.9 ± 1.6% in the aqueductus mesencephali and 15.5 ± 6.6% in the fourth ventricle. In 11 cases a significant asymmetry was found between the lateral ventricles. The results suggest that it may be normal for a dog to have one of the lateral ventricles 1.5 times larger than the other. The correlation between body weight and CSF volume was linear, indicating that the current dosage protocols for myelography, based on a hypothetical proportional relationship with body weight, may have to be revised.
Dosages for myelography procedures in dogs are based on a hypothetical proportional relationship between bodyweight and cerebrospinal fluid (CSF) volume. Anecdotal radiographic evidence and recent studies have challenged the existence of such a defined relationship in dogs. The objectives of this prospective cross-sectional study were to describe CSF volumes using magnetic resonance imaging (MRI) in a group of clinically healthy dogs, measure the accuracy of MRI CSF volumes, and compare MRI CSF volumes with dog physical measurements. A sampling perfection with application optimized contrast using different flip-angle evolution MRI examination of the central nervous system was carried out on 12 healthy, male mongrel dogs, aged between 3 and 5 years with a bodyweight range of 7.5-35.0 kg. The images were processed with image analysis freeware (3D Slicer) in order to calculate the volume of extracranial CSF. Cylindrical phantoms of known volume were included in scans and used to calculate accuracy of MRI volume estimates. The accuracy of MRI volume estimates was 99.8%. Extracranial compartment CSF volumes ranged from 20.21 to 44.06 ml. Overall volume of the extracranial CSF increased linearly with bodyweight, but the proportional volume (ml/bodyweight kilograms) of the extracranial CSF was inversely proportional to bodyweight. Relative ratios of volumes in the cervical, thoracic, and lumbosacral regions were constant. Findings indicated that the current standard method of using body weight to calculate dosages of myelographic contrast agents in dogs may need to be revised.
Zusammenfassung Gegenstand und Ziel Epilepsie gehört auch bei Katzen zu den häufigeren chronischen neurologischen Erkrankungen. Bei der diagnostischen Aufarbeitung spielt die magnetresonanztomographische (weiters: MRT) Untersuchung eine zentrale Rolle. Bei hippocampalen MRT-Veränderungen kann die Frage, ob diese Veränderungen die Ursache oder die Folge der Symptome repräsentieren, oft nicht beantwortet werden.Ziel der Studie war die retrospektive Aufarbeitung der MRT-Befunde einer großen Patientenkohorte an epileptischen Katzen. Material und Methoden Insgesamt wurden 143 Katzen aufgeteilt in 3 Altersgruppen (< 1 Jahr, zw. 1–6 Jahre, > 6 Jahre) in die Studie aufgenommen. Die MRT-Befunde wurden in die folgenden 4 Kategorien aufgeteilt: Unauffällig, extrahippocampale Veränderungen, hippocampale Signaländerungen ohne und mit Kontrastmittelaufnahme. Die Prävalenz und die Auftrittswahrscheinlichkeit der unterschiedlichen MRT-Veränderungen wurden in den Altersgruppen mittels Chi-Quadrat-Test und nominaler Regression geprüft. Ergebnisse Etwa die Hälfte der Katzen (49 %) wies einen unauffälligen MRT-Befund auf. Extrahippocampale Veränderungen wurden in 18 % der Katzen festgestellt. Hippocampale Veränderungen waren bei 33 % der Katzen zu finden. Die hippocampale Sklerose konnte histopathologisch in allen vier MRT-Gruppen (unauffällige MRT, extrahippocampale Veränderungen, hippocampale Signaländerung mit und ohne Kontrastmittelanreicherung) nachgewiesen werden. Schlussfolgerung und klinische Relevanz Bei etwa 50 % der epileptischen Katzen ergibt die Gehirn MRT einen unauffälligen Befund; extrahippocampale Veränderungen sind insbesondere bei älteren Katzen zu erwarten. Die hippocampalen MRT-Veränderungen sind oft ätiologisch nicht zuzuordnen. Weitere Untersuchungen sind erforderlich, um die Bedeutung von hippocampalen Veränderungen zu verstehen.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.