Avaliação ultrassonográfica e elastográfica do sistema nervoso central em fetos caninos braquicefálicos
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Data
2019-12-18
Autores
Pavan, Letícia [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Os objetivos deste estudo foram avaliar as características ultrassonográficas (modo-B e da elastografia) das estruturas do sistema nervoso central (SNC) de fetos caninos, como método complementar para predizer a idade gestacional, avaliar o desenvolvimento dos conceptos, estabelecer padrões de normalidade e auxiliar no diagnóstico de anormalidades gestacionais. Foram utilizadas 26 cadelas braquicefálicas, da raça Bulldog Inglês, com idade entre um e quatro anos e meio. Os exames ultrassonográficos foram realizados em três momentos da gestação, aos 34, 49 e 60 dias, com o aparelho ACUSON S2000/SIEMENS e transdutor multifrequencial matricial e linear de 9,0 MHz. Foram avaliados três fetos de cada fêmea. Verificou-se a presença da massa cerebral fetal, seu formato em corte transversal, ecotextura e ecogenicidade, presença e mensuração da translucência nucal (TN). O cerebelo foi avaliado em corte transversal, verificando-se seu formato, ecotextura, ecogenicidade e comprimento do seu eixo maior. A elastografia foi aplicada ao tecido fetal cerebral e cerebelar obtendo-se velocidades médias de cisalhamento (m/s) e elastogramas. O delineamento experimental foi em blocos casualizado (cadelas), com parcelas subdivididas no tempo (dias gestacionais), e a análise estatística foi realizada pela análise de variância (ANOVA) com medidas repetidas no tempo. Das 26 ninhadas estudadas, 18 tiveram somente fetos saudáveis, 4 apresentaram fetos com anasarca, 3 apresentaram fetos com defeitos da parede abdominal e 1 apresentou os dois tipos de alteração. A TN foi maior (P=0,0249) nos fetos das cadelas que apresentaram anasarcas na ninhada (1,8±0,77 mm) em relação às ninhadas normais (1,4±0,48 mm), e de acordo com a análise ROC o valor de corte para a presença de anasarca foi de TN>1,45 mm (sensibilidade=61,54%, especificidade=70,18%). O cerebelo apresentou formato de “banana”, com bordas mais ecogênicas, ecotextura homogênea e hipoecoico em relação aos tecidos adjacentes. O diâmetro transversal cerebelar (DTC) no dia 60 foi maior que no dia 49 (P=0,0001). A rigidez tecidual do cerebelo foi maior aos 60 dias quando comparada com 49 dias (P=0,0006). A SWV da massa cerebral apresentou um aumento gradativo (P=0,0001) nos três momentos gestacionais avaliados e correlacionou-se positivamente com dias para o parto (DPP) (P=0,0001). De acordo com o elastograma, tanto o cérebro quanto o cerebelo tornaram-se mais rígidos com o avanço dos dias gestacionais. Conclui-se que a mensuração da espessura da TN no 34º dia gestacional apresentou potencial diagnóstico para o desenvolvimento de fetos com anasarca durante a gestação de cadelas. Com as características ultrassonográficas do cerebelo e da massa cerebral, a mensuração do DTC e a elastografia do sistema nervoso central foi possível acompanhar o desenvolvimento dos conceptos e estabelecer padrões de normalidade.
The objectives of this study were to evaluate the ultrasound (B-mode and elastography) characteristics of canine fetal central nervous system structures as complementary method to predict gestational age, to evaluate the development of the fetuses, to establish normality patterns and to assist in diagnosis of gestational abnormalities. Twenty-six brachycephalic female dogs of the English Bulldog breed, aged between one and four and a half years were used. Ultrasound examinations were performed at three gestational moments, at 34, 49 and 60 gestation days, with the ACUSON S2000 / SIEMENS device and a 9.0 MHz matrix and linear multifrequency transducer. Three fetuses of each female were evaluated. The presence of fetal brain mass, its cross-sectional shape, echotexture and echogenicity, presence and measurement of nuchal translucency (TN) were verified. The cerebellum was evaluated in cross-section, verifying its shape, echotexture, echogenicity and length of its major axis. Elastography was applied to the fetal brain and cerebellar tissue to obtain mean velocities and elastograms. The experimental design was randomized in blocks (bitches) with plots subdivided in time (gestational days) and statistical analysis was performed by analysis of variance (ANOVA) with repeated measures over time. Of the 26 litters studied, 18 had only healthy fetuses, 4 had fetuses with anasarca, 3 had fetuses with abdominal wall defects, and 1 had both types of alterations. The TN was higher (P=0.0249) in the fetuses of bitches that presented anasarcas in the litter (1.8 ± 0.77 mm) in relation to the normal litters (1.4 ± 0.48 mm), and according to ROC analysis the cohort value for the presence of anasarca was TN>1.45 mm (sensitivity=61.54%, specificity=70.18). The cerebellum was “banana shaped”, with more echogenic edges, homogeneous and hypoechoic echotexture in relation to adjacent tissues. The transverse cerebellar diameter (TCD) on day 60 was greater than on day 49 (P=0.0001). Cerebellar tissue stiffness was higher at 60 days compared to 49 days (P=0.0006). Brain mass SWV showed a gradual increase (P=0.0001) in the three gestational moments evaluated and was positively correlated with days before parturition (DBP) (P=0.0001). According to the elastogram, both the brain and cerebellum became more rigid as gestational days progressed. In conclusion, the measurement of TN thickness on the 34th day of gestation demonstrated potential for diagnosis for the development of anasarca fetuses during bitches' gestation. The sonographic characteristics of the cerebellum and brain mass, the measurement of the DTC and the elastography of the central nervous system made it possible to verify the development of the concepts and to determine normality patterns.
The objectives of this study were to evaluate the ultrasound (B-mode and elastography) characteristics of canine fetal central nervous system structures as complementary method to predict gestational age, to evaluate the development of the fetuses, to establish normality patterns and to assist in diagnosis of gestational abnormalities. Twenty-six brachycephalic female dogs of the English Bulldog breed, aged between one and four and a half years were used. Ultrasound examinations were performed at three gestational moments, at 34, 49 and 60 gestation days, with the ACUSON S2000 / SIEMENS device and a 9.0 MHz matrix and linear multifrequency transducer. Three fetuses of each female were evaluated. The presence of fetal brain mass, its cross-sectional shape, echotexture and echogenicity, presence and measurement of nuchal translucency (TN) were verified. The cerebellum was evaluated in cross-section, verifying its shape, echotexture, echogenicity and length of its major axis. Elastography was applied to the fetal brain and cerebellar tissue to obtain mean velocities and elastograms. The experimental design was randomized in blocks (bitches) with plots subdivided in time (gestational days) and statistical analysis was performed by analysis of variance (ANOVA) with repeated measures over time. Of the 26 litters studied, 18 had only healthy fetuses, 4 had fetuses with anasarca, 3 had fetuses with abdominal wall defects, and 1 had both types of alterations. The TN was higher (P=0.0249) in the fetuses of bitches that presented anasarcas in the litter (1.8 ± 0.77 mm) in relation to the normal litters (1.4 ± 0.48 mm), and according to ROC analysis the cohort value for the presence of anasarca was TN>1.45 mm (sensitivity=61.54%, specificity=70.18). The cerebellum was “banana shaped”, with more echogenic edges, homogeneous and hypoechoic echotexture in relation to adjacent tissues. The transverse cerebellar diameter (TCD) on day 60 was greater than on day 49 (P=0.0001). Cerebellar tissue stiffness was higher at 60 days compared to 49 days (P=0.0006). Brain mass SWV showed a gradual increase (P=0.0001) in the three gestational moments evaluated and was positively correlated with days before parturition (DBP) (P=0.0001). According to the elastogram, both the brain and cerebellum became more rigid as gestational days progressed. In conclusion, the measurement of TN thickness on the 34th day of gestation demonstrated potential for diagnosis for the development of anasarca fetuses during bitches' gestation. The sonographic characteristics of the cerebellum and brain mass, the measurement of the DTC and the elastography of the central nervous system made it possible to verify the development of the concepts and to determine normality patterns.
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Palavras-chave
ARFI, Cão, Cerebelo, Cérebro, Translucência nucal, Dog, Cerebellum, Brain, Nuchal translucency