 Okay. So what are the different manifestations that we see in normal ovarian physiology? Well, you can see here that we've got a diagram of an ovary with multiple different stages of follicular development. So you can see a number of different cysts over that time. So we'll call them cysts even though they're physiologically normal. And they range from a follicular cyst to a corpus luteum cyst, to a hemorrhagic cyst, and sometimes ovarian inclusion cysts. And those are the main four stages that we see, but there are even some stages in between, as you can see from the diagram. So depending on the stage of when the patient is imaged, the ovary can have a very dynamic appearance because of the variable physiology. And they're quite dynamic organs. So it's important to keep that in mind when you're evaluating patients with ultrasound and MR, particularly in the premenopausal age group. What are the commonly seen ovarian cysts? And you'll see here that I have cysts in quotation marks. And that's because I don't necessarily want to apply the label of a cyst, which may imply some mythology to a normal appearance of an ovary depending on its physiologic state. So we tend to call these appearances cysts, but keep in mind that cysts can be normal or abnormal, depending on whether they fit with the ovarian physiology. So here we've got a follicular cyst and then we've got a corpus luteum or corpus albicans, hemorrhagic cyst, endometrioma, and ovarian inclusion cyst. And those are some of the different ultrasound appearances you may see when scanning patients, particularly in the premenopausal state. So a follicular cyst is hormone dependent. And it really develops because of arrested follicular development. So when the follicle stops growing, you have a lot of fluid in the sac. And if you tend to image the patient at that point, you're going to see that. And that's just normal physiology. Then we've got the corpus luteum, which develops after ovulation. And it's got the function of maintaining the early pregnancy. So it has a bit of a thick wall, it's quite vascular. And that's the typical appearance that we'll see on sonography. The hemorrhagic cyst is usually quite characteristic on ultrasound. And it tends to have the appearance of a cobweb or a lace like configuration with lots of vibrant strands. And it's got kind of an angular clot that you can see sort of retracting. And that's quite often seen outlined here with very angular and straight margins. So that's what a hemorrhagic cyst looks like. And most of those resolve within eight weeks. The endometrioma is a cystic collection of mixed blood products. And it is very characteristically described as having diffuse low level internal echos. As you can see throughout the cyst here, it's got this kind of ground glass appearance. And it does have through transmission. And sometimes there is overlap between a hemorrhagic cyst and an endometrioma. And then finally here, we've got an ovarian inclusion cyst, which happens because of invagination of the cortical surface of the ovary following ovulation. And that results in a simple cyst being formed. And usually those measure less than 10 millimeters in size. And often we still see them in the postmenopausal population.