Study On A New Method Of Predicting Gestational Age In Cats Using Ultrasound And Creation Of Ultrasound Map Of Fetal Development

The purpose of this experiment was to(1)Measure the gestational sac diameter(GSD),biparietal diameter(BD),placental thickness(GP),maximal abdominal diameter,lens(long axis and short axis),length of the ulnar and radius,long axis of the kidneys,diameter of the posterior vena cava and the diameter of the aorta of the Bengal leopard cat,exploring new methods for gestational age prediction.(2)Measurement of resistance index(RI),pulse index(PI),end-systolic peak velocity(EDV),and diastolic velocity(PSV)of fetal umbilical artery,umbilical vein,posterior vena cava,and aorta,(2)Established the fetus Blood flow parameters,by measuring resistance index(RI),pulsation index(PI),end-systolic peak velocity(EDV),diastolic velocity(PSV)of umbilical artery,umbilical vein,posterior vena cava,aortic.Evaluation of fetal hemodynamics.(3)To initially create an ultrasound map of fetal fetus at different developmental stages to provide the basis for clinical pregnancy diagnosis.In this study,24 fetuses of pregnant female cats were continuously monitored until the birth by SIUI Apogee 1200 V veterinary ultrasound diagnostic apparatus.The maternal cats were examined using an ultrasound between the 10 th and 15 th days after the first mating to determine if they were pregnant.Once pregnant,use a 12.5 MHz linear array probe to check every two days and measure relevant indicators until delivery.All values are expressed as mean ±SD.In this experiment,ultrasonic monitoring of the Bengal leopard cat during the entire gestation period showed that the whole pregnancy cycle can be divided into three stages: early stage,middle stage and late stage.Early pregnancy:From the first mating to the 28 th day of pregnancy,At this stage,the fetal limb differentiation has been completed.In addition to the original heart beating can be clearly observed,other organs can not be clearly distinguished.The first exploration of the gestational sac at 13 days of pregnancy.The embryo buds and primitive heart tube pulsation and the original placenta can be detected in 15 days of pregnancy.Spinal cavity observed at 21 days of pregnancy.Mid-pregnancy:28~45 days,at this stage,some organs such as two-chamber heart(28 days)and four-chamber heart(34 days),lung and diaphragm(28 days),liver and stomach(26 days),kidney(34 days),bladder(29 days),eyes(31 days),ulna and radius and fibula tibia(30 days),posterior vena cava(32 days),intestinal canal(40 days),and bone calcification were also observed,Fetal movement(28 days)also begins at this stage.Late pregnancy:From 45 days to delivery.At this stage,the fetus gradually matures,fetal kidney cortex and medulla can be clearly distinguished.A slight expansion of the renal pelvis,until full-term,bone calcification is evident,atrial and ventricles are clearly visible,intestinal cavity begins to appear.In this experiment,SPSS22.0 was used to perform linear regression analysis on the experimental data,and Seven new formulas for ultrasound prediction of gestational age were obtained.(1)Left kidney long axis Y=23.573X+28.380,right kidney long axis Y=23.123X+27.109,applicable range is d?40;Maximum abdominal diameter(MAD): Y=11.662X+20.308,applicable range is d?30;(3)Diameter of the posterior vena cava :Y=106.446X+23.586;applicable range is d?32.(4)Aortic diameter: Y=100.995X+25.665;applicable range is d? 40;(5)Lens minor axis: Y=71.171X+16.706,Lens long axis: Y=57.305X+19.231;applicable range is d?32;(6)Length of ulna: Y=18.323X+26.559;applicable range is d?34(7)length of radius: Y=19.485X+26.738;applicable range is d?34;X represents the length of the relevant measurement indicator(cm),and Y represents the gestational age.Because the cat is a zonal placenta,it is not easy to accurately position when measuring,and the linear regression is more discrete,so it is not recommended to use placental thickness to predict gestational age.By monitoring the ovaries and uterus,postpartum uterus,and fetal development at various stages during the estrus phase of the Bengali leopard cat,Initially created an ultrasound map of cat uterus,ovary and fetus at different stages of development.The experiment found that the size of the ovaries during estrus was 0.92×0.59 cm,and the size of the follicles was 0.2~0.3 cm.Through measurement of fetal umbilical artery,umbilical vein,aortic and posterior vena cava blood flow parameters,Throughout pregnancy,PSV and EDV in the aorta,umbilical cord arterial and vein,and posterior vena cava all increase as gestational age increases.In addition to the aorta,PI and RI decreased with increasing gestational age.The RI of the aorta does not change much,and PI is almost constant throughout the pregnancy.In the first 5 weeks of pregnancy,the umbilical artery has only PSV.Then gradually appeared diastolic blood flow.Fetal posterior vena cava and aortic diastolic blood flow can only be detected in about 40 days.