Description of technique and lower reference limit for magnetic resonance imaging of hippocampal volumetry in dogs

Milne, Marjorie; Anderson, Garry A.; Chow, Kathleen Ella; O’Brien, Terence J.; Moffat, Bradford A.; Long, Sam

doi:10.2460/ajvr.74.2.224

Cited by 24 publications

(40 citation statements)

References 39 publications

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“…Common MRI features are decreased hippocampal volume, increased signal intensity on T2‐weighted imaging as well as disturbed internal architecture of the hippocampus . Attempts have been made to evaluate the use of volumetry and to define an MRI protocol for assessment of the canine hippocampus . Nothing comparable has been published for FHN.…”

Section: Discussionmentioning

confidence: 99%

Clinical Characterization of Epilepsy of Unknown Cause in Cats

Wahle

Brühschwein

Matiasek

et al. 2013

Veterinary Internal Medicne

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BackgroundThe diagnosis of feline epilepsy of unknown cause (EUC) requires a thorough diagnostic evaluation, otherwise the prevalence of EUC could be overestimated.HypothesisFeline EUC is a clinically defined disease entity, which differs from feline hippocampal necrosis by the absence of magnetic resonance imaging (MRI) signal alteration of the hippocampus. The objectives of this study were (1) to evaluate the prevalence of EUC in a hospital population of cats by applying well‐defined inclusion criteria, and (2) to describe the clinical course of EUC.AnimalsEighty‐one cats with recurrent seizures.MethodsRetrospective study—medical records were reviewed for cats presented for evaluation of recurrent seizures (2005–2010). Inclusion criteria were a defined diagnosis based on laboratory data, and either MRI or histopathology. Final outcome was confirmed by telephone interview with the owner. Magnetic resonance images were reviewed to evaluate hippocampal morphology and signal alterations.ResultsEpilepsy of unknown cause was diagnosed in 22% of cats with epilepsy. Physical, neurologic, and laboratory examinations, and either 1.5 T MRI and cerebrospinal fluid analysis or postmortem examination failed to identify an underlying cause. Cats with EUC had a higher survival rate (P < .05) and seizure remission occurred frequently (44.4%).Conclusion and Clinical ImportanceA detailed clinical evaluation and diagnostic imaging with MRI is recommended in any cat with recurrent seizures. The prognosis of cats with normal MRI findings and a clinical diagnosis of EUC are good. Standardized imaging guidelines should be established to assess the hippocampus in cats.

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Section: Discussionmentioning

confidence: 99%

Clinical Characterization of Epilepsy of Unknown Cause in Cats

Wahle

Brühschwein

Matiasek

et al. 2013

Veterinary Internal Medicne

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“…[1][2][3][4] The disease in dogs occurs at a frequency similar to epilepsy in people, with seizures occurring in 0.5-5% of all dogs and with idiopathic epilepsy being the most common underlying cause. 5,6 Although antiepileptic drugs (AEDs) continue to form the cornerstone of epilepsy treatment in this species, up to 25% of epileptic dogs remain refractory to medication. 6 This compares to a similar proportion in the human epileptic population, among whom approximately one third continue to suffer seizures despite medication.…”

mentioning

confidence: 99%

“…5,6 Although antiepileptic drugs (AEDs) continue to form the cornerstone of epilepsy treatment in this species, up to 25% of epileptic dogs remain refractory to medication. 6 This compares to a similar proportion in the human epileptic population, among whom approximately one third continue to suffer seizures despite medication. 7 For a subset of human patients with hippocampal sclerosis, resection of the mesial temporal lobe will result in a reduction in seizure frequency of 80-90%, but for many patients this is inappropriate because of the location of the seizure focus, unacceptable adverse effects such as memory impairment, or multiple seizure types.…”

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confidence: 99%

Placement of Deep Brain Electrodes in the Dog Using the Brainsight Frameless Stereotactic System: A Pilot Feasibility Study

Long

Frey

Freestone

et al. 2013

Veterinary Internal Medicne

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BackgroundDeep brain stimulation (DBS) together with concurrent EEG recording has shown promise in the treatment of epilepsy. A novel device is capable of combining these 2 functions and may prove valuable in the treatment of epilepsy in dogs. However, stereotactic implantation of electrodes in dogs has not yet been evaluated.ObjectiveTo evaluate the feasibility and safety of implanting stimulating and recording electrodes in the brain of normal dogs using the Brainsight system and to evaluate the function of a novel DBS and recording device.AnimalsFour male intact Greyhounds, confirmed to be normal by clinical and neurologic examinations and hematology and biochemistry testing.Methods MRI imaging of the brain was performed after attachment of fiducial markers. MRI scans were used to calculate trajectories for electrode placement in the thalamus and hippocampus, which was performed via burr hole craniotomy. Postoperative CT scanning was performed to evaluate electrode location and accuracy of placement was calculated. Serial neurologic examinations were performed to evaluate neurologic deficits and EEG recordings obtained to evaluate the effects of stimulation.ResultsElectrodes were successfully placed in 3 of 4 dogs with a mean accuracy of 4.6 ± 1.5 mm. EEG recordings showed evoked potentials in response to stimulation with a circadian variation in time‐to‐maximal amplitude. No neurologic deficits were seen in any dog.Conclusions and Clinical ImportanceStereotactic placement of electrodes is safe and feasible in the dog. The development of a novel device capable of providing simultaneous neurostimulation and EEG recording potentially represents a major advance in the treatment of epilepsy.

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“…The field of view (FoV) used for all measurements corresponded 224 × 320 mm. The paradorsal planes (T2w, T1w MP-RAGE and T2 relaxometry) were oriented perpendicular to the long axis of the hippocampus with planning and placing the paradorsal slice on the sagittal plane -as described and recommended previously (Hasboun et al, 1996;Milne et al, 2013).…”

Section: Image Acquisitionmentioning

confidence: 99%

“…There are several works studying hippocampal changes particularly using quantitative MR methods, such as hippocampal volumetry in epileptic companion animals, supporting the importance and role of the hippocampal formation in feline (Fatzer et al, 2000;Brini et al, 2004;Schmied et al, 2008;Mizoguchi et al, 2014) and canine epilepsy (Vullo et al, 1996;Kuwabara et al, 2010;Milne et al, 2013). These studies described the qualitative MR findings of hippocampal abnormalities (sclerosis, atrophy and necrosis) in dogs and cats.…”

mentioning

confidence: 99%

Novel approach to magnetic resonance imaging of epileptic dogs — T2 relaxometry of the brain with emphasised hippocampus

Lőrincz

Ansón

Csébi

et al. 2017

Acta Veterinaria Hungarica

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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.

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Description of technique and lower reference limit for magnetic resonance imaging of hippocampal volumetry in dogs

Cited by 24 publications

References 39 publications

Clinical Characterization of Epilepsy of Unknown Cause in Cats

Clinical Characterization of Epilepsy of Unknown Cause in Cats

Placement of Deep Brain Electrodes in the Dog Using the Brainsight Frameless Stereotactic System: A Pilot Feasibility Study

Novel approach to magnetic resonance imaging of epileptic dogs — T2 relaxometry of the brain with emphasised hippocampus

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