Made available in DSpace on 2015-12-06T23:45:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2010 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Objetivos: Mensuracao do volume dos ventriculos laterais cerebrais de fetos com ventriculomegalia pela ultrassonografia tridimensional (US3D) -metodo VOCAL- e da Ressonancia Magnetica Fetal (RM) para avaliacao da concordancia entre metodos e reprodutibilidade. Metodo: Estudo e corte transversal que avaliou 30 fetos com diagnostico de ventriculomegalia (VM) entre 20 e 36 6/7 semanas gestacionais. Cada ventriculo (VL) foi medido inicialmente por dois observadores para comparacao entre metodos e posteriormente por mais dois observadores para avaliacao de reprodutibilidade. Os exames ultrassonograficos foram realizados em aparelho ACCUVIX XQ (Medison, Coreia do Sul) com software VOCAL 30º e as RM em sistema Sonata de 1,5T (Siemens, Alemanha) com software ARGUS. Os VL foram estratificados conforme sua posicao em relacao ao transdutor e o tamanho do atrio ventricular. Para estudo de concordancia e reprodutibilidade intra e interobservador calculamos os coeficientes de correlacao intraclasse (CCI) e contruimos Graficos de Bland-Altman. Resultados: Todos os VL foram adequadamente medidos pela ressonancia magnetica (RM) e 59 pelo metodo VOCAL. Os dados obtidos pelo VOCAL e pela RM apresentaram excelente concordancia geral (CCI 0,928, IC 95% [0,876;0,958]) e em todas as categorias analisadas. Os graficos de Bland- Altman confirmaram estes achados com media das diferencas: 1,62cm3 e desvio=padrao:± 8,41 cm3 na analise geral. Nao foram observadas diferencas significativas entre ventriculos distais e proximais. Os ventriculos acima de 30cm3 apresentam discrepancias maiores devido a artefatos de imagem. Conclusoes: A volumetria dos VL pelo VOCAL e pela RM apresenta excelente concordancia e reprodutibilidade. Ventriculos acima de 30cm3 apresentam / Objective: Ventricular atria conventional measurement in the axial plane alone has proven not to give information about ventriculomegaly (VM) etiology nor prognosis. Our aim was to evaluate lateral ventricles morphology of VM / hydrocephaly fetuses using 3D-US renderization by VOCALô technique and MRI and verify morphologic patterns related to etiology. Methods: 17 fetuses presenting with ventricular enlargement (atria >10mm) were submitted to sonographic and MRI exams. Threedimensional datasets were acquired with ACCUVIX XQô ultrasound system (Medison, Korea), from a coronal reference plane and postprocessed by the rotational imaging program VOCALô 30o . The ventricular volume was measured and 3D ventricular reconstruction was then exhibited in the screen. MRI study was analyzed in the three plans in all sequences (T1, T2 and T2 gradient). Morphologic aspects as global shape, anterior, posterior and inferior horn characteristics, wall irregularities and deformities were analyzed and related to etiology factor. Results: 29% of the cases were secondary to Arnold-Chiari Syndrome and presented with global dilation of the three-horns, regular ventricular walls keeping the ventricular shape. Cases related to aqueduct stenosis presented with ependymal rupture and wall irregularities in advances cases. Ventricular shape was rounder with important enlargement of the body and posterior horn. Corpus callosum agenesis cases presented with small ventricular volumes, thin shape, normal or slightly enlarged anterior and inferior horns with dilation restricted to posterior horn. Cases related to trisomy 18 and cytomegalovirus presented irregular ventricular walls associated with anomalous ventricular shapes, suggesting parenchymal destruction. Conclusion: Ventricular morphology evaluation gives important information on etiology of ventricular enlargement, supporting prognosis prediction and decision making process of the affected fetuses and their families. / FAPESP: 2008/58201-3 / BV UNIFESP: Teses e dissertações

The discovery of neural stem cells within the adult CNS has indicated an enormous potential in facilitating neuronal regeneration after injury. Studies from our laboratory have suggested that manipulation of the Rb/E2f pathway can directly impact embryonic and adult neurogenesis, thereby having tremendous potential for neuronal regeneration therapies. Recently, two new members of the Rb/E2f pathway have been discovered, the atypical E2fs: E2f7 and E2f8. Initial studies have suggested that atypical E2fs regulate diverse processes such as cell proliferation, DNA-stress response, apoptosis, however, their importance in the brain are unknown. To analyze their function during brain development, we crossed Nestin-Cre mice with mice bearing a conditional E2f7/E2f8 allele to delete both E2f7 and E2f8 in neural precursor cells. Whereas cortical development was largely unaffected by E2f7/E2f8 deficiency, we observed an enlargement of the lateral ventricles occurring postnatally, a brain condition named ventriculomegaly. We then looked at the ependymal cells, which are the cells lining the wall of the lateral ventricles, to determine if these cells were affected by the absence of atypical E2fs. We found progressive denaturation of the ependymal cell layer, distortion of the ependymal motile cilia and reactive astrocytes within the layer. We identified Gli3, a component of the Sonic hedgehog pathway (Shh), as a target for E2fs, including atypical E2fs. We unravelled a novel mechanism by which atypical E2fs regulate the expression of Gli3, leading to up-regulation of Numb/NumbL, which in consequence destabilizes cadherins organization within the ependymal cell layer. In conclusion, our work suggests that E2f7 and E2f8 transcription factors play an essential role in maintaining the ependymal cell barrier.

No description available.

Introdução: As mucopolissacaridoses (MPS) constituem um grupo de doenças lisossômicas caracterizadas pela deficiência de uma das enzimas responsáveis pela degradação dos glicosaminoglicanos (GAGs). É difícil determinar a incidência precisa de hidrocefalia em pacientes com MPS, pois não possui uma definição formal por consenso. Além disso, é difícil distinguir a hidrocefalia comunicante da dilatação ventricular secundária à atrofia cerebral, porque ambas apresentam características clínicas e neuroradiológicas comuns. Embora várias técnicas sejam usadas para identificar pacientes com MPS com maior probabilidade de ter hidrocefalia e responder ao tratamento cirúrgico, não existe um método definitivo para provar o diagnóstico. Objetivos: Avaliar a relação entre ventriculomegalia, volume cerebral e liquórico, fluxo de líquor aquedutal e cervical e pressão de abertura liquórica em pacientes com MPS, e detectar potenciais biomarcadores para as alterações da circulação liquórica. Métodos: Quarenta e três pacientes com MPS (12 MPS I, 15 MPS II, 5 MPS III, 9 MPS IV A e 2 MPS VI) realizaram testes clínicos e de desenvolvimento neurológico, ressonância magnética (RM) nas sequências T1, T2, FLAIR e por contraste de fase, seguidas por punção lombar para avaliação da pressão de abertura liquórica. Para a análise das variáveis da RM, foram medidos: volume cerebral e liquórico, carga de lesões na substância branca (LSB), índice de Evans, largura do terceiro ventrículo, ângulo do corpo caloso, espaços perivasculares dilatados (EPVD), estenose da junção craniocervical, volume de stroke aquedutal e cervical, e concentração de GAGs no líquor. Resultados: As formas graves e a macrocefalia estiveram significativamente associadas com a ventriculomegalia, principalmente com o índice de Evans (p = 0.004 e p = 0.008, respectivamente). A carga de LSB apresentou uma forte correlação com as medidas ventriculares e o volume liquórico ventricular (rs = 0.51, p = 0.001). A dilatação ventricular supratentorial e o volume de líquor ventricular apresentaram uma correlação moderada com o volume de stroke aquedutal (VSA) (rs = 0.46, p = 0.002). A pressão de abertura liquórica não se correlacionou nem com as três medidas da ventriculomegalia, nem com a volumetria liquórica, nem com o VSA. O prejuízo cognitivo e os EPVD mostraram uma associação significativa com a ventriculomegalia, especialmente com a largura do terceiro ventrículo (p = 0.019 e p = 0.001, respectivamente). Os EPVD em quantidade aumentada também apresentaram uma significativa associação com o VSA elevado (p = 0.007). Conclusões: Nos pacientes com MPS, a ventriculomegalia está associada a um fenótipo grave da doença, maior declínio cognitivo e maior extensão das LSB e EPVD. Existem associações entre as medidas de fluxo liquórico e as medidas relacionadas à volumetria liquórica. Além disso, as medidas volumétricas estão associadas a quantidade de EPVD. / Background: The mucopolysaccharidoses (MPS) are a group of lysosomal diseases characterized by a deficiency in one of the lysosomal enzymes responsible to degrade glycosaminoglycans (GAGs). The precise incidence of hydrocephalus in patients with MPS is hard to determine, because it lacks a formal, consensus-based definition. In addition, it is difficult to distinguish communicating hydrocephalus from ventricular dilatation secondary to brain atrophy, because both share common clinical and neuroradiological features. Although various techniques are used to identify MPS patients who are most likely to have hydrocephalus and respond to surgical treatment, no definitive method exists to prove diagnosis. Objectives: To assess the relationship between ventriculomegaly, brain and cerebrospinal fluid (CSF) volumes, aqueductal and cervical CSF flows, and CSF opening pressure in MPS patients, and to provide potential biomarkers for abnormal CSF circulation. Methods: Forty-three MPS patients (12 MPS I, 15 MPS II, 5 MPS III, 9 MPS IV A and 2 MPS VI) performed clinical and neurodevelopmental tests, and T1, T2, FLAIR and phase-contrast magnetic resonance imaging (MRI) followed by a lumbar puncture with the CSF opening pressure assessment. For the analysis of MRI variables, the following measures were performed: brain and CSF volumes, white matter (WM) lesion load, Evans’ index, third ventricle width, callosal angle, dilated perivascular spaces (PVS), craniocervical junction stenosis, aqueductal and cervical CSF stroke volumes, and CSF GAGs concentration Results: The severe forms and the macrocephaly were significantly associated with the ventriculomegaly, mainly with the Evans’ index (p = 0.004 and p = 0.008, respectively). The WM lesion load presented a high correlation with the ventricular measurements and the ventricular CSF volume (rs = 0.51, p = 0.001). The supratentorial ventricular dilation and the ventricular CSF volume presented a moderate correlation with the aqueductal CSF stroke volume (ACSV) (rs = 0.46, p = 0.002). The CSF opening pressure did not correlate with either the three measures of ventriculomegaly, either with the CSF volumetry or with the ACSV. The cognitive impairment and the dilated PVS showed a significant association with the ventriculomegaly, especially with the width of the third ventricle (p = 0.019 and p = 0.001, respectively). Increased amount of dilated PVS also had a significant association with the elevated ACSV (p = 0.007). Conclusions: In MPS patients ventriculomegaly is associated with a severe phenotype, increased cognitive decline, WM lesion severity and enlarged PVS. There are associations between CSF flow measurements and measurements related to CSF volumetrics. Also, the volumetric measurements are associated with the degree of dilated PVS.

Introdução: As mucopolissacaridoses (MPS) constituem um grupo de doenças lisossômicas caracterizadas pela deficiência de uma das enzimas responsáveis pela degradação dos glicosaminoglicanos (GAGs). É difícil determinar a incidência precisa de hidrocefalia em pacientes com MPS, pois não possui uma definição formal por consenso. Além disso, é difícil distinguir a hidrocefalia comunicante da dilatação ventricular secundária à atrofia cerebral, porque ambas apresentam características clínicas e neuroradiológicas comuns. Embora várias técnicas sejam usadas para identificar pacientes com MPS com maior probabilidade de ter hidrocefalia e responder ao tratamento cirúrgico, não existe um método definitivo para provar o diagnóstico. Objetivos: Avaliar a relação entre ventriculomegalia, volume cerebral e liquórico, fluxo de líquor aquedutal e cervical e pressão de abertura liquórica em pacientes com MPS, e detectar potenciais biomarcadores para as alterações da circulação liquórica. Métodos: Quarenta e três pacientes com MPS (12 MPS I, 15 MPS II, 5 MPS III, 9 MPS IV A e 2 MPS VI) realizaram testes clínicos e de desenvolvimento neurológico, ressonância magnética (RM) nas sequências T1, T2, FLAIR e por contraste de fase, seguidas por punção lombar para avaliação da pressão de abertura liquórica. Para a análise das variáveis da RM, foram medidos: volume cerebral e liquórico, carga de lesões na substância branca (LSB), índice de Evans, largura do terceiro ventrículo, ângulo do corpo caloso, espaços perivasculares dilatados (EPVD), estenose da junção craniocervical, volume de stroke aquedutal e cervical, e concentração de GAGs no líquor. Resultados: As formas graves e a macrocefalia estiveram significativamente associadas com a ventriculomegalia, principalmente com o índice de Evans (p = 0.004 e p = 0.008, respectivamente). A carga de LSB apresentou uma forte correlação com as medidas ventriculares e o volume liquórico ventricular (rs = 0.51, p = 0.001). A dilatação ventricular supratentorial e o volume de líquor ventricular apresentaram uma correlação moderada com o volume de stroke aquedutal (VSA) (rs = 0.46, p = 0.002). A pressão de abertura liquórica não se correlacionou nem com as três medidas da ventriculomegalia, nem com a volumetria liquórica, nem com o VSA. O prejuízo cognitivo e os EPVD mostraram uma associação significativa com a ventriculomegalia, especialmente com a largura do terceiro ventrículo (p = 0.019 e p = 0.001, respectivamente). Os EPVD em quantidade aumentada também apresentaram uma significativa associação com o VSA elevado (p = 0.007). Conclusões: Nos pacientes com MPS, a ventriculomegalia está associada a um fenótipo grave da doença, maior declínio cognitivo e maior extensão das LSB e EPVD. Existem associações entre as medidas de fluxo liquórico e as medidas relacionadas à volumetria liquórica. Além disso, as medidas volumétricas estão associadas a quantidade de EPVD. / Background: The mucopolysaccharidoses (MPS) are a group of lysosomal diseases characterized by a deficiency in one of the lysosomal enzymes responsible to degrade glycosaminoglycans (GAGs). The precise incidence of hydrocephalus in patients with MPS is hard to determine, because it lacks a formal, consensus-based definition. In addition, it is difficult to distinguish communicating hydrocephalus from ventricular dilatation secondary to brain atrophy, because both share common clinical and neuroradiological features. Although various techniques are used to identify MPS patients who are most likely to have hydrocephalus and respond to surgical treatment, no definitive method exists to prove diagnosis. Objectives: To assess the relationship between ventriculomegaly, brain and cerebrospinal fluid (CSF) volumes, aqueductal and cervical CSF flows, and CSF opening pressure in MPS patients, and to provide potential biomarkers for abnormal CSF circulation. Methods: Forty-three MPS patients (12 MPS I, 15 MPS II, 5 MPS III, 9 MPS IV A and 2 MPS VI) performed clinical and neurodevelopmental tests, and T1, T2, FLAIR and phase-contrast magnetic resonance imaging (MRI) followed by a lumbar puncture with the CSF opening pressure assessment. For the analysis of MRI variables, the following measures were performed: brain and CSF volumes, white matter (WM) lesion load, Evans’ index, third ventricle width, callosal angle, dilated perivascular spaces (PVS), craniocervical junction stenosis, aqueductal and cervical CSF stroke volumes, and CSF GAGs concentration Results: The severe forms and the macrocephaly were significantly associated with the ventriculomegaly, mainly with the Evans’ index (p = 0.004 and p = 0.008, respectively). The WM lesion load presented a high correlation with the ventricular measurements and the ventricular CSF volume (rs = 0.51, p = 0.001). The supratentorial ventricular dilation and the ventricular CSF volume presented a moderate correlation with the aqueductal CSF stroke volume (ACSV) (rs = 0.46, p = 0.002). The CSF opening pressure did not correlate with either the three measures of ventriculomegaly, either with the CSF volumetry or with the ACSV. The cognitive impairment and the dilated PVS showed a significant association with the ventriculomegaly, especially with the width of the third ventricle (p = 0.019 and p = 0.001, respectively). Increased amount of dilated PVS also had a significant association with the elevated ACSV (p = 0.007). Conclusions: In MPS patients ventriculomegaly is associated with a severe phenotype, increased cognitive decline, WM lesion severity and enlarged PVS. There are associations between CSF flow measurements and measurements related to CSF volumetrics. Also, the volumetric measurements are associated with the degree of dilated PVS.

Introdução: As mucopolissacaridoses (MPS) constituem um grupo de doenças lisossômicas caracterizadas pela deficiência de uma das enzimas responsáveis pela degradação dos glicosaminoglicanos (GAGs). É difícil determinar a incidência precisa de hidrocefalia em pacientes com MPS, pois não possui uma definição formal por consenso. Além disso, é difícil distinguir a hidrocefalia comunicante da dilatação ventricular secundária à atrofia cerebral, porque ambas apresentam características clínicas e neuroradiológicas comuns. Embora várias técnicas sejam usadas para identificar pacientes com MPS com maior probabilidade de ter hidrocefalia e responder ao tratamento cirúrgico, não existe um método definitivo para provar o diagnóstico. Objetivos: Avaliar a relação entre ventriculomegalia, volume cerebral e liquórico, fluxo de líquor aquedutal e cervical e pressão de abertura liquórica em pacientes com MPS, e detectar potenciais biomarcadores para as alterações da circulação liquórica. Métodos: Quarenta e três pacientes com MPS (12 MPS I, 15 MPS II, 5 MPS III, 9 MPS IV A e 2 MPS VI) realizaram testes clínicos e de desenvolvimento neurológico, ressonância magnética (RM) nas sequências T1, T2, FLAIR e por contraste de fase, seguidas por punção lombar para avaliação da pressão de abertura liquórica. Para a análise das variáveis da RM, foram medidos: volume cerebral e liquórico, carga de lesões na substância branca (LSB), índice de Evans, largura do terceiro ventrículo, ângulo do corpo caloso, espaços perivasculares dilatados (EPVD), estenose da junção craniocervical, volume de stroke aquedutal e cervical, e concentração de GAGs no líquor. Resultados: As formas graves e a macrocefalia estiveram significativamente associadas com a ventriculomegalia, principalmente com o índice de Evans (p = 0.004 e p = 0.008, respectivamente). A carga de LSB apresentou uma forte correlação com as medidas ventriculares e o volume liquórico ventricular (rs = 0.51, p = 0.001). A dilatação ventricular supratentorial e o volume de líquor ventricular apresentaram uma correlação moderada com o volume de stroke aquedutal (VSA) (rs = 0.46, p = 0.002). A pressão de abertura liquórica não se correlacionou nem com as três medidas da ventriculomegalia, nem com a volumetria liquórica, nem com o VSA. O prejuízo cognitivo e os EPVD mostraram uma associação significativa com a ventriculomegalia, especialmente com a largura do terceiro ventrículo (p = 0.019 e p = 0.001, respectivamente). Os EPVD em quantidade aumentada também apresentaram uma significativa associação com o VSA elevado (p = 0.007). Conclusões: Nos pacientes com MPS, a ventriculomegalia está associada a um fenótipo grave da doença, maior declínio cognitivo e maior extensão das LSB e EPVD. Existem associações entre as medidas de fluxo liquórico e as medidas relacionadas à volumetria liquórica. Além disso, as medidas volumétricas estão associadas a quantidade de EPVD. / Background: The mucopolysaccharidoses (MPS) are a group of lysosomal diseases characterized by a deficiency in one of the lysosomal enzymes responsible to degrade glycosaminoglycans (GAGs). The precise incidence of hydrocephalus in patients with MPS is hard to determine, because it lacks a formal, consensus-based definition. In addition, it is difficult to distinguish communicating hydrocephalus from ventricular dilatation secondary to brain atrophy, because both share common clinical and neuroradiological features. Although various techniques are used to identify MPS patients who are most likely to have hydrocephalus and respond to surgical treatment, no definitive method exists to prove diagnosis. Objectives: To assess the relationship between ventriculomegaly, brain and cerebrospinal fluid (CSF) volumes, aqueductal and cervical CSF flows, and CSF opening pressure in MPS patients, and to provide potential biomarkers for abnormal CSF circulation. Methods: Forty-three MPS patients (12 MPS I, 15 MPS II, 5 MPS III, 9 MPS IV A and 2 MPS VI) performed clinical and neurodevelopmental tests, and T1, T2, FLAIR and phase-contrast magnetic resonance imaging (MRI) followed by a lumbar puncture with the CSF opening pressure assessment. For the analysis of MRI variables, the following measures were performed: brain and CSF volumes, white matter (WM) lesion load, Evans’ index, third ventricle width, callosal angle, dilated perivascular spaces (PVS), craniocervical junction stenosis, aqueductal and cervical CSF stroke volumes, and CSF GAGs concentration Results: The severe forms and the macrocephaly were significantly associated with the ventriculomegaly, mainly with the Evans’ index (p = 0.004 and p = 0.008, respectively). The WM lesion load presented a high correlation with the ventricular measurements and the ventricular CSF volume (rs = 0.51, p = 0.001). The supratentorial ventricular dilation and the ventricular CSF volume presented a moderate correlation with the aqueductal CSF stroke volume (ACSV) (rs = 0.46, p = 0.002). The CSF opening pressure did not correlate with either the three measures of ventriculomegaly, either with the CSF volumetry or with the ACSV. The cognitive impairment and the dilated PVS showed a significant association with the ventriculomegaly, especially with the width of the third ventricle (p = 0.019 and p = 0.001, respectively). Increased amount of dilated PVS also had a significant association with the elevated ACSV (p = 0.007). Conclusions: In MPS patients ventriculomegaly is associated with a severe phenotype, increased cognitive decline, WM lesion severity and enlarged PVS. There are associations between CSF flow measurements and measurements related to CSF volumetrics. Also, the volumetric measurements are associated with the degree of dilated PVS.

Einleitung: Französische Bulldoggen (FBD) werden beinahe täglich zur weiteren Abklärung intrakranieller Erkrankungen in der Klinik für Kleintiere der Universität Leipzig vorgestellt. Die während der Magnetresonanztomographie (MRT) des Gehirns häufig beobachtete subjektive Ventrikulomegalie der Seitenventrikel (SV) wirft die Frage auf, ob es sich hierbei um einen rassespezifischen Normalbefund oder einen Befund mit pathologischem Charakter handelt. Ziele der Untersuchung: Ziel war die Messung der Volumina der SV neurologisch unauffälliger FBD sowie der Vergleich dieser Werte mit denen des Dackels als mesozephaler Referenzrasse mit einer ähnlichen Körpermasse. Darüber hinaus wurde der Einfluss von Gewicht, Geschlecht, Kastrationsstatus und Alter der Tiere auf die Volumina untersucht. Die Häufigkeit optisch wahrnehmbarer ventrikulärer Asymmetrien für beide Rassen sowie deren Seitenverteilung wurde erfasst und die Grenze für die optische Wahrnehmung einer Asymmetrie ermittelt. Tiere, Material und Methoden: Insgesamt wurden vierzig FBD und fünfzehn Dackel prospektiv in die Studie aufgenommen. Auf der Basis eines Besitzerfragebogens zu neurologischen Symptomen (Verhalten des Tieres, Koordinationsstörungen, epileptische Anfälle) und einer klinischen neurologischen Untersuchung wurden die Tiere als neurologisch unauffällig hinsichtlich intrakranieller Erkrankungen eingestuft. Von jedem Tier wurden T1-gewichtete MRT-Aufnahmen des Gehirns in transversaler Schnittebene (Schichtdicke 2,0 mm) angefertigt. Zufallsbefunde in der MRT-Untersuchung, welche die Morphologie des Gehirnparenchyms, die Liquorzusammensetzung oder den Liquorfluss beeinflussen könnten, führten zum Ausschluss der Tiere. Die SV der Hunde wurden über die Software ITK-SNAP manuell segmentiert und volumetrisch vermessen. Zusätzlich wurden die SV rein optisch hinsichtlich vorliegender Asymmetrien beurteilt. Im positiven Fall wurde die größere Seite dokumentiert. Die Analyse der Bilddaten wurde einmalig durch die über Erfahrung in der manuellen Segmentation verfügende Autorin (JD) selbst durchgeführt. Die ermittelten Daten beider Rassen wurden durch mehrere Medianvergleichstests auf signifikante Unterschiede geprüft (Wilcoxon-Mann-Whitney-Test, χ² – Test, Kruskal-Wallis-Test, van der Waerden-Test). Der Einfluss von Geschlecht, Kastrationsstatus, Alter und Gewicht der Tiere auf das Seitenventrikelvolumen wurden mit einer linearen Regressionsanalyse überprüft. Die Durchführung dieser Studie fand Zustimmung durch die Ethikkommission der Veterinärmedizinischen Fakultät der Universität Leipzig. Ergebnisse: Das Volumen der SV der FBD belief sich im Median auf 786 mm³ (linker SV = 380 mm³; rechter SV = 413 mm³). Das Volumen der SV der Dackel lag im Median bei 1141 mm³ (linker SV = 589 mm³; rechter SV = 619 mm³). Der Unterschied der Volumina zwischen den Rassen war, unabhängig vom gewählten Testverfahren, statistisch nicht signifikant. Alter (p = 0,28), Geschlecht (p = 0,39), Kastrationsstatus (p = 0,09) und Gewicht (p = 0,60) der Tiere hatten keinen statistisch signifikanten Einfluss auf das Gesamtvolumen der SV. Asymmetrien der SV lagen bei 50 % der FBD und 60 % der Dackel vor, wobei in 50 % (FBD) bzw. 66,7 % (Dackel) dieser Fälle der linke SV vergrößert war. Die Seitenverteilung des größeren Ventrikels bei vorliegender Asymmetrie hatte sowohl für die FBD (p = 0,83) und den Dackel (p = 0,35) keine statistische Signifikanz. Asymmetrien zwischen den beiden SV konnten ab einem prozentualen Volumenunterschied von 22 % sicher optisch von der Untersucherin (JD) in den MRT-Aufnahmen erkannt werden. Schlussfolgerung: Die Vermutung, dass FBD zu einem erhöhten Volumen der SV und damit physiologisch zu Ventrikulomegalien neigen, konnte nicht bestätigt werden. Die untersuchten Tiere zeigten deskriptiv sogar geringere Volumina als die zum Vergleich gewählten Dackel und die in der Literatur verfügbaren Daten anderer Hunderassen. Das Vorliegen vergrößerter SV sollte daher nicht als anatomische Normvariante gewertet und bis zum Beweis des Gegenteils als pathologisch betrachtet werden. Asymmetrien der SV treten dagegen, wie auch bei anderen Hunderassen, bei neurologisch unauffälligen FBD in annähernd der Hälfte der Tiere auf. / Introduction: French Bulldogs (FB) are presented to our clinic almost daily for diagnostic workup and therapy of intracranial disorders. Subjective lateral ventriculomegaly is frequently observed on diagnostic imaging of these dogs. This raises the question whether this is a breed-specific normal finding or a finding with pathological character. Objective: To measure the volume of the lateral ventricles (LV) of neurologically unremarkable FB and compare these values with those of a mesocephalic breed of nearly the same weight (Dachshunds). The influence of body weight, sex, neutering status and age was investigated. Additionally, ventricular asymmetry was assessed and, if present, the enlarged side was documented. The threshold of subjective detection of asymmetric ventricles was calculated. Animals, material and methods: Forty FB and fifteen Dachshunds were included in this study prospectively. Animals were classified as healthy regarding intracranial disease via an owner questionnaire about neurological symptoms of the animal (behaviour of the animal, deficits in coordination, potential epileptic seizures) and a complete neurological examination. Transversal, T1-weighted MRI brain images with a slice thickness of 2,0 mm were obtained of each animal. Incidental findings on diagnostic imaging which could influence the morphology of brain parenchyma and the circulation or composition of cerebrospinal fluid lead to exclusion of the animals. LV were segmented manually and quantitative volumetric measurements were obtained using the open-source software ITK-SNAP. Assessment of lateral ventricular asymmetry and, if present, of the enlarged side was also done in this software. These steps were performed once by the author (JD) of this study, who already had experience using this software for manual image segmentation. Volumetric data of both breeds were checked for significant differences of medians by several statistical tests (Wilcoxon-Mann-Whitney-test, χ² – test, Kruskal-Wallis-test, van der Waerden-test). The influence of sex, neutering status, age and body weight on the LV volume was verified via a linear regression analysis. The Ethics Commitee of the Faculty of Veterinary Medicine, University of Leipzig, approved the concept and execution of this study. Results: Total median LV volume of the FB was 786 mm³ (left LV = 380 mm³; right LV = 413 mm³). For the Dachshunds, median volumes were 1141 mm³ in total and 589 mm³ (left LV) and 619 mm³ (right LV) respectively. There was no statistic significant difference of LV volume between the breeds, independent of the statistical test used. Age (p = 0,28), sex (p = 0,39), neutering status (p = 0,09) and body weight (p = 0,60) had no statistically significant influence on LV volume as well. 50 % of FB and 60 % of the Dachshunds had a LV asymmetry. The incidence of ventricular asymmetry was statistically significant in both breeds (p < 0,001). The LV was larger than the right in 50 % of FB and 66,7 % of Dachshunds. This finding was not statistically significant (p = 0,83 in FB and 0,35 in Dachshunds). A percentage difference in volume of 22 % between the lateral ventricles was determined as threshold value for visual detection of asymmetries. Conclusion: The assumption of a higher volume of the LV and therefore physiological ventriculomegaly in the FB breed could not be confirmed. Furthermore, the FB in this study had lower volumes of the LV compared to the values of Dachshunds and available data of other breeds in veterinary literature. Therefore, ventriculomegaly should not be considered as a normal anatomic variant in this breed and instead be considered as pathological, leading to further diagnostic workup. In contrast, lateral ventricular asymmetry seems to be a common incidental finding in neurologically normal FB as well as in other dog breeds.