Limits...
Comparison of the Relationship between Cerebral White Matter and Grey Matter in Normal Dogs and Dogs with Lateral Ventricular Enlargement.

Schmidt MJ, Laubner S, Kolecka M, Failing K, Moritz A, Kramer M, Ondreka N - PLoS ONE (2015)

Bottom Line: There is a distinct relationship between white matter and grey matter in the cerebrum of all eutherian mammals.Whereas no significant different adjusted means of the grey matter could be determined, the group of brachycephalic dogs had significantly larger adjusted means of lateral cerebral ventricles and significantly less adjusted means of relative white matter volume.Based on the changes in the relative proportion of WM and CSF volume, and the unchanged GM proportions in dogs with ventriculomegaly, we rather suggest that distension of the lateral ventricles might be the underlying cause of pressure related periventricular loss of white matter tissue, as occurs in internal hydrocephalus.

View Article: PubMed Central - PubMed

Affiliation: Department of Veterinary Clinical Sciences, Clinic for Small Animals, Justus-Liebig-University-Giessen, Giessen, Germany.

ABSTRACT
Large cerebral ventricles are a frequent finding in brains of dogs with brachycephalic skull conformation, in comparison with mesaticephalic dogs. It remains unclear whether oversized ventricles represent a normal variant or a pathological condition in brachycephalic dogs. There is a distinct relationship between white matter and grey matter in the cerebrum of all eutherian mammals. The aim of this study was to determine if this physiological proportion between white matter and grey matter of the forebrain still exists in brachycephalic dogs with oversized ventricles. The relative cerebral grey matter, white matter and cerebrospinal fluid volume in dogs were determined based on magnetic-resonance-imaging datasets using graphical software. In an analysis of covariance (ANCOVA) using body mass as the covariate, the adjusted means of the brain tissue volumes of two groups of dogs were compared. Group 1 included 37 mesaticephalic dogs of different sizes with no apparent changes in brain morphology, and subjectively normal ventricle size. Group 2 included 35 brachycephalic dogs in which subjectively enlarged cerebral ventricles were noted as an incidental finding in their magnetic-resonance-imaging examination. Whereas no significant different adjusted means of the grey matter could be determined, the group of brachycephalic dogs had significantly larger adjusted means of lateral cerebral ventricles and significantly less adjusted means of relative white matter volume. This indicates that brachycephalic dogs with subjective ventriculomegaly have less white matter, as expected based on their body weight and cerebral volume. Our study suggests that ventriculomegaly in brachycephalic dogs is not a normal variant of ventricular volume. Based on the changes in the relative proportion of WM and CSF volume, and the unchanged GM proportions in dogs with ventriculomegaly, we rather suggest that distension of the lateral ventricles might be the underlying cause of pressure related periventricular loss of white matter tissue, as occurs in internal hydrocephalus.

No MeSH data available.


Related in: MedlinePlus

Volume rendering of brain tissues of interest.3D viewer mode of the graphical software AMIRA. The voxels of the tissue of interest (white matter/grey matter) of each slice have been assembled and are now displayed as a 3D model. Each tissue can be displayed solid or transparent. The localizer lines support the segmentation process. As they are displayed in both the 2D images and the 3D model, the thalamus, medulla and cerebellum can be accurately separated from the volume of interest.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4418575&req=5

pone.0124174.g003: Volume rendering of brain tissues of interest.3D viewer mode of the graphical software AMIRA. The voxels of the tissue of interest (white matter/grey matter) of each slice have been assembled and are now displayed as a 3D model. Each tissue can be displayed solid or transparent. The localizer lines support the segmentation process. As they are displayed in both the 2D images and the 3D model, the thalamus, medulla and cerebellum can be accurately separated from the volume of interest.

Mentions: In the first step the cerebellum, brainstem, thalamus and hippocampus were segmented, assigned to a mask and excluded from the volume of interest (Fig 3). As the WM of the cerebral hemispheres, i.e. the internal capsules, merges into the thalamus running caudad towards the brainstem, a perpendicular line connecting the caudal border of the optic chiasm and the rostral border of the intermediate mass was drawn in reconstructed sagittal images. This line was automatically represented in all other imaging planes including the 3D model and was used to delineate the internal capsule transition from the cerebral hemispheres to the diencephalon. WM caudal to this line was not included. The lateral ventricles were segmented in a third step. The lateral ventricles included the Monroe`s foramen. The third and fourth ventricle was not included. The segmented WM GM and CSF partitions were calculated and graphically presented by the program (Fig 4 and S1 Table). The calculated volumes were put into relation to the whole cerebral volume and expressed as the relative CSF volume and relative GM- and WM volume. Furthermore the relationship between WM and GM was expressed as the WM/GM ratio.


Comparison of the Relationship between Cerebral White Matter and Grey Matter in Normal Dogs and Dogs with Lateral Ventricular Enlargement.

Schmidt MJ, Laubner S, Kolecka M, Failing K, Moritz A, Kramer M, Ondreka N - PLoS ONE (2015)

Volume rendering of brain tissues of interest.3D viewer mode of the graphical software AMIRA. The voxels of the tissue of interest (white matter/grey matter) of each slice have been assembled and are now displayed as a 3D model. Each tissue can be displayed solid or transparent. The localizer lines support the segmentation process. As they are displayed in both the 2D images and the 3D model, the thalamus, medulla and cerebellum can be accurately separated from the volume of interest.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4418575&req=5

pone.0124174.g003: Volume rendering of brain tissues of interest.3D viewer mode of the graphical software AMIRA. The voxels of the tissue of interest (white matter/grey matter) of each slice have been assembled and are now displayed as a 3D model. Each tissue can be displayed solid or transparent. The localizer lines support the segmentation process. As they are displayed in both the 2D images and the 3D model, the thalamus, medulla and cerebellum can be accurately separated from the volume of interest.
Mentions: In the first step the cerebellum, brainstem, thalamus and hippocampus were segmented, assigned to a mask and excluded from the volume of interest (Fig 3). As the WM of the cerebral hemispheres, i.e. the internal capsules, merges into the thalamus running caudad towards the brainstem, a perpendicular line connecting the caudal border of the optic chiasm and the rostral border of the intermediate mass was drawn in reconstructed sagittal images. This line was automatically represented in all other imaging planes including the 3D model and was used to delineate the internal capsule transition from the cerebral hemispheres to the diencephalon. WM caudal to this line was not included. The lateral ventricles were segmented in a third step. The lateral ventricles included the Monroe`s foramen. The third and fourth ventricle was not included. The segmented WM GM and CSF partitions were calculated and graphically presented by the program (Fig 4 and S1 Table). The calculated volumes were put into relation to the whole cerebral volume and expressed as the relative CSF volume and relative GM- and WM volume. Furthermore the relationship between WM and GM was expressed as the WM/GM ratio.

Bottom Line: There is a distinct relationship between white matter and grey matter in the cerebrum of all eutherian mammals.Whereas no significant different adjusted means of the grey matter could be determined, the group of brachycephalic dogs had significantly larger adjusted means of lateral cerebral ventricles and significantly less adjusted means of relative white matter volume.Based on the changes in the relative proportion of WM and CSF volume, and the unchanged GM proportions in dogs with ventriculomegaly, we rather suggest that distension of the lateral ventricles might be the underlying cause of pressure related periventricular loss of white matter tissue, as occurs in internal hydrocephalus.

View Article: PubMed Central - PubMed

Affiliation: Department of Veterinary Clinical Sciences, Clinic for Small Animals, Justus-Liebig-University-Giessen, Giessen, Germany.

ABSTRACT
Large cerebral ventricles are a frequent finding in brains of dogs with brachycephalic skull conformation, in comparison with mesaticephalic dogs. It remains unclear whether oversized ventricles represent a normal variant or a pathological condition in brachycephalic dogs. There is a distinct relationship between white matter and grey matter in the cerebrum of all eutherian mammals. The aim of this study was to determine if this physiological proportion between white matter and grey matter of the forebrain still exists in brachycephalic dogs with oversized ventricles. The relative cerebral grey matter, white matter and cerebrospinal fluid volume in dogs were determined based on magnetic-resonance-imaging datasets using graphical software. In an analysis of covariance (ANCOVA) using body mass as the covariate, the adjusted means of the brain tissue volumes of two groups of dogs were compared. Group 1 included 37 mesaticephalic dogs of different sizes with no apparent changes in brain morphology, and subjectively normal ventricle size. Group 2 included 35 brachycephalic dogs in which subjectively enlarged cerebral ventricles were noted as an incidental finding in their magnetic-resonance-imaging examination. Whereas no significant different adjusted means of the grey matter could be determined, the group of brachycephalic dogs had significantly larger adjusted means of lateral cerebral ventricles and significantly less adjusted means of relative white matter volume. This indicates that brachycephalic dogs with subjective ventriculomegaly have less white matter, as expected based on their body weight and cerebral volume. Our study suggests that ventriculomegaly in brachycephalic dogs is not a normal variant of ventricular volume. Based on the changes in the relative proportion of WM and CSF volume, and the unchanged GM proportions in dogs with ventriculomegaly, we rather suggest that distension of the lateral ventricles might be the underlying cause of pressure related periventricular loss of white matter tissue, as occurs in internal hydrocephalus.

No MeSH data available.


Related in: MedlinePlus