A Subset of Dogs with Presumptive Idiopathic Epilepsy Show Hippocampal Asymmetry: A Volumetric Comparison with Non-Epileptic Dogs Using MRI

Estey, Chelsie M.; Dewey, Curtis W.; Rishniw, Mark; Lin, David M.; Bouma, Jennifer; Sackman, Joseph; Burkland, Erica

doi:10.3389/fvets.2017.00183

Cited by 19 publications

(21 citation statements)

References 40 publications

(46 reference statements)

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“…Those results are similar to our findings and indicate that applying an AR > 6% of the hippocampus enables an accurate assessment of HA in dogs . The second possible and described protocol for the assessment of unilateral atrophy of the hippocampus is the use of an AR > 12.6% . It has been suggested that this protocol is more specific for identifying canine epileptic hippocampal asymmetry, although the protocol applied in this study was also used by other authors .…”

Section: Discussionsupporting

confidence: 89%

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Comparison of electroencephalographic findings with hippocampal magnetic resonance imaging volumetry in dogs with idiopathic epilepsy

Czerwik

Płonek

Podgórski

et al. 2018

Veterinary Internal Medicne

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Background: In humans, temporal lobe epilepsy (TLE), is a type of focal epilepsy occurring mainly in the mesial TLE (mTLE), commonly associated with hippocampal sclerosis (HS). Objectives: According to recent studies, TLE might also occur in dogs and could be associated with hippocampal atrophy (HA)/HS. To date, hippocampal lesions have not been correlated with electroencephalographic (EEG) findings in epileptic dogs. Animals: An EEG examination, brain magnetic resonance imaging, and volumetric assessment of the hippocampus were performed in 16 nonepileptic and 41 epileptic dogs. Methods: In this retrospective study, the presence and localization of EEG‐defined epileptiform discharges (EDs) was blindly evaluated. The hippocampus was measured and assessed for unilateral atrophy. The results of EEG and volumetric findings were correlated to determine whether the functional epileptic focus is equivalent to structural changes. Results: The median hippocampal asymmetric ratio (AR) in epileptic dogs was significantly greater than in the control group (P < .001). Using a cut‐off threshold AR of >6%, 56% (23/41) of the dogs were characterized with unilateral HA. Of those animals, 35% (8/23) had EDs in the temporal leads and 26% (6/23) had no EDs. In 88% (7/8) of dogs with EDs in the temporal leads that had unilateral HA, the EDs correlated with the side of the decreased hippocampal volume. Conclusions and Clinical Importance: The results indicate an association between the presence of EDs detectable on EEG and a decrease in the unilateral hippocampal volume in some cases of canine idiopathic epilepsy that might reflect features of human mTLE.

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Section: Discussionsupporting

confidence: 89%

“…It is predicted that HS is related to approximately 80% of all TLE epilepsies in adult humans . According to recent studies, HS, HA, or both play an important role in canine epileptogenesis, and may reflect TLE or mTLE …”

Section: Introductionmentioning

confidence: 99%

Comparison of electroencephalographic findings with hippocampal magnetic resonance imaging volumetry in dogs with idiopathic epilepsy

Czerwik

Płonek

Podgórski

et al. 2018

Veterinary Internal Medicne

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“…3), and total brain volume for each dog, using Mimics Ò software. Volumetric measurements for total brain volume were performed as previously described (Estey et al, 2017). Both investigators used previously published anatomic landmarks for all measurements (Leigh et al, 2008) and both were blinded to the clinical status of the dogs in the study.…”

Section: Methodsmentioning

confidence: 99%

Interthalamic adhesion size in aging dogs with presumptive spontaneous brain microhemorrhages: a comparative retrospective MRI study of dogs with and without evidence of canine cognitive dysfunction

Dewey

Rishniw

Johnson

et al. 2020

PeerJ

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Objective Spontaneous brain microhemorrhages in elderly people are present to some degree in Alzheimer’s disease patients but have been linked to brain atrophy in the absence of obvious cognitive decline. Brain microhemorrhages have recently been described in older dogs, but it is unclear whether these are associated with brain atrophy. Diminution of interthalamic adhesion size-as measured on MRI or CT-has been shown to be a reliable indicator of brain atrophy in dogs with canine cognitive dysfunction (CCD) in comparison with successfully aging dogs. We hypothesized that aging dogs with brain microhemorrhages presenting for neurologic dysfunction but without obvious features of cognitive decline would have small interthalamic adhesion measurements, like dogs with CCD, compared with control dogs. The objective of this study was to compare interthalamic adhesion size between three groups of aging (>9 years) dogs: (1) neurologically impaired dogs with presumptive spontaneous brain microhemorrhages and no clinical evidence of cognitive dysfunction (2) dogs with CCD (3) dogs without clinical evidence of encephalopathy on neurologic examination (control dogs). MR images from 52 aging dogs were reviewed and measurements were obtained of interthalamic adhesion height (thickness) and mid-sagittal interthalamic adhesion area for all dogs, in addition to total brain volume. Interthalamic adhesion measurements, either absolute or normalized to total brain volume were compared between groups. Signalment (age, breed, sex), body weight, presence and number of SBMs, as well as other abnormal MRI findings were recorded for all dogs. Results All interthalamic adhesion measurement parameters were significantly (P < 0.05) different between control dogs and affected dogs. Both dogs with cognitive dysfunction (12/15; 80%) and dogs with isolated brain microhemorrhages had more microhemorrhages than control dogs (3/25; 12%). Affected dogs without cognitive dysfunction had significantly more microhemorrhages than dogs with cognitive dysfunction. In addition to signs of cognitive impairment for the CCD group, main clinical complaints for SBM and CCD dogs were referable to central vestibular dysfunction, recent-onset seizure activity, or both. Geriatric dogs with spontaneous brain microhemorrhages without cognitive dysfunction have similar MRI abnormalities as dogs with cognitive dysfunction but may represent a distinct disease category.

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“…Quantitative volumetric measurements of both hippocampi as well as total brain volume were acquired for each dog, as previously described ( Figure 1 ). 12 Anatomic landmarks for measurements were used from published reference information. 13,14…”

Section: Methodsmentioning

confidence: 99%

Canine cognitive dysfunction (CCD) patients have reduced total hippocampal volume compared with aging control dogs: a comparative MRI study

Rishniw

Platt³

et al. 2020

Preprint

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42Hippocampal atrophy is a key pathologic and MRI feature of human Alzheimer's disease (AD). 43Hippocampal atrophy has not been documented via MRI in canine cognitive dysfunction (CCD), 44 which is considered the dog model of human AD. The purpose of this retrospective comparative 45 volumetric MRI study was to compare total hippocampal volumes between successfully aging 46 (control) dogs and dogs diagnosed with CCD. Mimics ® software was used to derive total 47 54 55 56 57 58 59 60 61 4 62 7 126 status (CCD vs control). Agreement between repeated measurements was examined using Limits 127 of Agreement analysis. 15 128 Results 129We included 16 dogs with CCD and 26 control dogs in the study. Dogs with CCD were older 130 than control dogs (median age 13 yrs vs 11.5 yrs; P=0.0002); however, we could detect no 131 negative correlation between advancing age and reduced hippocampal volume in either group 132 ( Figure 2). The CCD group comprised 2 Shih Tzus, 2 Springer spaniels and one each of 133

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A Subset of Dogs with Presumptive Idiopathic Epilepsy Show Hippocampal Asymmetry: A Volumetric Comparison with Non-Epileptic Dogs Using MRI

Cited by 19 publications

References 40 publications

Comparison of electroencephalographic findings with hippocampal magnetic resonance imaging volumetry in dogs with idiopathic epilepsy

Comparison of electroencephalographic findings with hippocampal magnetic resonance imaging volumetry in dogs with idiopathic epilepsy

Interthalamic adhesion size in aging dogs with presumptive spontaneous brain microhemorrhages: a comparative retrospective MRI study of dogs with and without evidence of canine cognitive dysfunction

Canine cognitive dysfunction (CCD) patients have reduced total hippocampal volume compared with aging control dogs: a comparative MRI study

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