INTRODUCCIÓN:La ecografía Doppler Duplex transcraneal es una técnica de exploración muy difundida en medicina humana por su gran utilidad en el campo de los cuidados intensivos, ya que permite estudiar de una forma no invasiva las patologías vasculares y sistémicas con repercusión en el sistema nervioso central. Además, dada su inocuidad y accesibilidad, se ha convertido no sólo en una técnica de diagnóstico, sino también en una herramienta muy útil para la monitorización de dichas patologías. Sin embargo, el Doppler Duplex color tranascraneal aún no se ha desarrollado en medicina veterinaria como un elemento práctico de uso clínico.MOTIVACIÓN DE LA TESIS:El objetivo de la realización de este trabajo es contribuir al estudio de la circulación sanguínea cerebral en la especie canina.DESARROLLO TEÓRICO:Se han utilizado 30 perros de diferente raza, edad y sexo, clínicamente sanos, a los que se les realizó ecografía Doppler Duplex Color Transcraneal a través de la ventana temporal, para la exploración de las arterias cerebrales rostral, media y posterior, tanto del lado izquierdo como del derecho (polígono de Willis), a través de la ventana suboccipital, para el estudio de la arteria basilar. Se realizó un análisis del espectro Doppler en cada vaso objeto de estudio, se evaluó el patrón de ondas y se midió la Vs, Vm, Vd, IR e IP. Los resultados obtenidos fueron: arteria cerebral rostral derecha: Vs = - 40,20 ± 6,90, Vm = - 25,89 ± 4,90, Vd = - 18,10 ± 3,87, IR = 0,57 ± 0,06 e IP = 0,87 ± 0,17; arteria cerebral rostral izquierda: Vs = -39,81 ¿ 4,10, Vm = -25,67 ± 5,13, Vd = - 17,64 ± 3,20, IR = 0,56 ± 0,07 e IP = 0,85 ± 0,19; arteria cerebral media derecha: Vs = 62,59 ± 10,90, Vm = 32,77 ± 9,13, Vd = 23,17 ± 6,53, IR = 0,65 ± 0,08 e IP = 1,27 ± 0,37; arteria cerebral media izquierda: Vs = 62,37 ± 9,10, Vm = 32,04 ± 7,82, Vd = 24,19 ± 6,63, IR = 0,64 ± 0,07 e IP= 1,22 ± 0,31; arteria cerebral caudal derecha: Vs = 36,35 ± 6,82, Vm = 18,97 ± 3,39, Vd = 15,48 ± 2,17, IR = 0,59 ± 0,05 e IP= 1,10 ¿ 0,20; arteria cerebral caudal izquierda: Vs = 34,31 ± 7,40, Vm= 19,26 ± 5,18, Vd = 15,49 ± 4,20, IR = 0,57 ± 0,05 e IP = 1,00 ± 0,20; arteria basilar: Vs = -74,53 ± 18,70, Vm = -34,26 ± 11,80, Vd = -22,81 ± 8,70, IR = 0,72 ± 0,07 e IP = 1,57 ± 0,36.Para facilitar la identificación de las arterias exploradas a través de la ventana temporal se realizaron maniobras de compresión carotídea. En la arteria cerebral rostral, tras la compresión en la arteria carótida ipsilateral, la velocidad de flujo se redujo en todos los perros entre un 20 y 50 %. En la arteria cerebral media, después de la compresión de la arteria carótida ipsilateral, la velocidad de flujo descendió en todos los perros entre un 20 y un 50 %. En las arterias cerebral caudal y basilar no se observaron cambios tras la compresión de la arteria carótida ipsilateral y carotídea respectivamente. Se han evaluado también los cambios hemodinámicos en la circulación cerebral tras la administración de 2 protocolos de sedación, medetomidina (40 µg/kg por vía intramuscular) y medetomidina (10 µg/kg vía intramuscular) combinada con butorfanol (0,2 mg/kg vía intramucular). Tras la sedación con ambos protocolos se observó una disminución en los valores de las Vs, Vm y Vd en la arteria cerebral media y una disminución de la Vs, IR e IP en la arteria basilar. Por último se han descrito los cambios hemodinámicos observados en las principales arterias de la base del cerebro en dos casos clínicos: un perro con encefalopatía hepática debida a un shunt portosistémico congénito, en el que se observó un aumento del IP en las arterias cerbral media derecha, cerebral media izquierda y basilar, relacionado con un aumento de la presión intracraneal y otro perro con un carcinoma nasal que se extendía hasta la porción rostral del cerebro. La ecografía Doppler transcraneal mostró valores elevados de Vs, Vm y Vd, así como valores disminuidos de IR e IP en las arterias rostrales derecha e izquierda y en la arteria cerebral media, pudiéndose interpretar como hiperemeia. Se pudo observar, además una evidente asimetría en el lado izquierdo donde se encontraba el tumor.CONCLUSIÓN:La ecografía Doppler transcraneal es una técnica de diagnóstico por imagen que puede realizarse en el perro. 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