Final answer:
Normal echo changes in pregnancy include increased blood volume and anatomical enlargement, which are necessary adaptations for fetal development. These changes can be seen on an ultrasound, which uses echo times to construct images, allowing for the differentiation between normal and pathologic conditions. Advanced ultrasound techniques with higher frequency and resolution are required to clearly discern these differences.
Step-by-step explanation:
During pregnancy, the body undergoes various physiologic changes that are reflected in echocardiograms or ultrasound images. Normal changes include increased blood volume, enlargement of the uterus, and weight gain that comprises fetal weight, amniotic fluid, additional breast tissue, and a modest amount of fat storage. These normal adaptations are distinguishable from pathologic changes on an ultrasound, which may present abnormal growths or complications requiring medical attention. Ultrasound technology plays a critical role by using echo times to measure the distance to reflecting surfaces in the body and constructing images of the internal structures, showing changes in size, shape, or density that may indicate pathological conditions.
Applying this to echocardiograms during pregnancy, normal changes such as increased cardiac output and slightly altered heart size can be expected, as opposed to pathologic changes like those indicative of peripartum cardiomyopathy. The ultrasound must have sufficiently high frequency and resolution to detect these differences, ensuring that the period of the ultrasound is shorter than the minimum time resolution required for clear imaging.