 And next we'll talk about renal cysts. So the Bosnian classification was updated in 2019 in which they made it a little bit more specific on what they mean by thick and thin septations and how many septations is too many. For Bosnian one lesions, they should be well-defined, thin smooth wall, homogeneous simple fluid and no septational calcification. And the wall may enhance especially on MRI because we can see the wall better than perhaps on CT. With Bosnian two, they subclassified it into six subtypes and they get our cystic masses within a few septations. They can have calcifications. You also have your proteinaceous cyst that are intrinsically hyperdense on non-con. And they can be homogeneous non-enhancing masses that's more than 20 house units on post-contrast images and also some low attenuation masses that are too small to characterize. So some examples for Bosnian two lesions, you have a few thin septations that have some mural calcifications. That's okay for Bosnian two. And in this example is intrinsically bright lesion that does not enhance. So that is a proteinaceous cyst, also a Bosnian two. A Bosnian two F, then you have, the septations can be a little bit thickened or they have minimal thickening of one or more enhancing septa or many smooth thin septations. So something like this would fall into Bosnian two F in which you can, you have more than four very thin septations. Bosnian three, then you get to have thicker internal septations or you can have mural nodules that are obtusely marginate. So these are examples of Bosnian three. By the time you get to Bosnian four, then you have enhancing mural nodules that are very suspicious for RCC. And this paper by Dr. Silverman in radiology 2019 has this nice chart that really summarizes and help you sink into your mind what they mean by the thickness of the septations and how much is too thick. And also the mural nodules, the distinction between convex and concave borders.