Linear regression model analysis of the changes in relative grey matter (GM), white matter (WM)- and CSF volume and the WM/GMratio with increasing bodyweight in dogs.

<p>The relative grey matter (GM), white matter (WM), and CSF volume of the lateral venmtricles as well as the WM/GM-ratio is plotted against the bodyweight in two groups of dogs. The open circles represent dogs with subjectively normal ventricles, the filled circles represent dogs with enlarged ventricles. The adjusted means in the middle of the regression lines of the groups differs significantly.</p

Volume determination based on MRI-datasets.

<p>Image segmentation of white matter and grey matter using manual segmentation on a slice-by-slice basis from transverse images. Each tissue of interest is labelled red and thereby assigned to a group (mask). All masks are then assembled and the tissues can be depicted in volume form.</p

Breed, body weight and diagnosis of the dogs included in groups one and two.

<p>Breed, body weight and diagnosis of the dogs included in groups one and two.</p

Results of the one-way analysis of covariance.

<p>The table presents the results of the analysis of covariance testing the equality of slopes from the regression to the body weight (BW), the global relevance of the BW as a covariate (common slope different from zero) and the equality of adjusted means at mean BW = 8.26 kg between the groups. The adjusted means are presented including the standard error of means (SEM)</p><p>Results of the one-way analysis of covariance.</p

Volume rendering of brain tissues of interest.

<p>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.</p

Volume models of grey matter and white matter.

<p>Frontal (A) and dorsal view of a 3D model of the brain of a Jack Russell Terrier. The white matter is labelled in red and the grey matter is transparent grey.</p

Transverse MR brain images.

<p>Transverse MR brain images (T2-weighted) of four affected Eurasier dogs at the level of the cerebellar peduncles (B) and medulla oblongata (A, C, D). The myelencephalon appears unremarkable. The fourth ventricle has a cyst-like appearance in the rostral sections (B) and is continuous with retrocerebellar cerebrospinal fluid accumulations in the more caudal sections (A, C, D). A: dog 6; B: dog 7; C: dog 9; D: dog 10.</p

Frequencies of the main clinical features in the two patient cohorts.

<p>Frequencies of the main clinical features in the two patient cohorts.</p

Dorsal MR brain images.

<p>Dorsal MR brain images (T2-weighted) of the affected Eurasier dogs reveal a prominent midline defect with absent caudal portions of the cerebellar vermis (midline) and cerebellar hemispheres (lateral) in association with a large retrocerebellar fluid accumulation. A: dog 6; B: dog 7; C: dog 9; D: dog 10. Images A and D are located more ventrally than B and C.</p

Pedigree.

<p>Pedigree of Eurasier dogs with familial non-progressive ataxia and cerebellar hypoplasia resembling a Dandy-Walker like malformation (DWLM). Female dog, ○; male dog, □; black, confirmed cases; the numbers refer to the dog numbers in Tables <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0117670#pone.0117670.t001" target="_blank">1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0117670#pone.0117670.t002" target="_blank">2</a>; gray, suspected cases, based on clinical signs, not confirmed by imaging. All cases could be traced to a common female founder.</p