 So this next case is a 66-year-old male who had an indeterminate mass seen on CT imaging, also has a history of lung cancer, so they wanted to get an MRI to figure out whether this mass was a metastasis or something they don't need to worry about. So we'll start looking at our MR images, starting off with our T2-weighted images. As you scroll downwards, we can see a few liver lesions. However, the mass in question can see in the left hepatic lobe, a rather large mass as seen over here. On the T2 non-fat saturated image, again, we can see a very, very large mass occupying majority of the lateral left hepatic lobe. Its internal contents are sort of interesting in that a lot of it is T2 hyper intense, but there are certain areas within it that have even brighter T2 content that's almost very similar to CSF. The remaining T2 content looks a little bit darker than CSF. These findings are also well demonstrated on the T2 turbo-spin echo, the fat saturated image where you have predominantly hyper intense with certain components within it, even brighter than the overall hyper intense signal within this mass. The next set of sequences that we need to look at are the T1s, performed both in and out of phase to see if there's any fat or areas of increased susceptibility within this lesion. Again, we identify this large lesion in the left hepatic lobe. And really, on both the out of phase sequence and the in phase sequence, the lesion looks pretty much identical in that it's T1 hyper intense. And really on both the T1 out of phase sequence and the T1 in phase sequence, the lesion looks identical in that it's T1 hyper intense. There's no areas of signal loss in the out of phase image to suggest presence of fat and no areas of increased susceptibility on the in phase image as well. Next sequence we're going to look at is the T1 fat saturated pre-contrast image. What does this lesion look like on this sequence? So T1 pre-contrast fat set image, predominantly T1 hyper intense. You can see this large lesion here. And interestingly enough, if you were to look at this very critically, those areas that were slightly brighter on the T2 weighted images have relatively darker signal on the T1 weighted images compared to the remaining portion of this mass. Up next, of course, is our post-contrast imaging that will allow us to determine what this lesion is going to be. So here we have our dynamic post-contrast images. And we can see this lesion in the left hepatic lobe. Let's talk a little bit about how this enhances. So if we look at this mass on the arterial phase images, we once again can see that this lesion, like some of the lesions we've seen so far, has peripheral enhancement and puddling of contrast that's discontinues. You can see along this portion here, there's no contrast. Again, continues along this portion next to it. On the portal venous phase images, we can see that this contrast extends out centrally and starts to fill in some of this lesion. And finally, on the equilibrium phase images, we can see that much of this lesion is filled with contrast except for those areas that were relatively bright on the T2 weighted images and relatively dark on the T1 weighted images. So there are certain pockets within this that actually never fill up with contrast with the remaining lesion filled with contrast. And so this lesion is compatible with a giant, giant hemangioma. Now the definition of giant hemangioma differs in the literature. Some people say it's more than four centimeters. Some people say six centimeters. I've read 10 centimeters, but generally I would say if it's more than five centimeters, it'll qualify as a giant hemangioma. And these lesions, again, can be asymptomatic like other hemangiomas, but because of their size, they can have some mass effect upon adjacent structures within the liver and even adjacent to the stomach. For example, over here causing potentially early satiety. One of the other things that can happen with this lesion is something called the Casabac Merit Syndrome, where there is a consumptive coagulopathy. So the lesion is so large it starts consuming all the clotting factors resulting in thrombocytopenia, so decreased platelets, and potentially disseminated intravascular coagulation, DIC. These sort of spaces that don't fill up with contrast are thought to reflect these clefts within this that could reflect central necrosis or liquefaction, and these sometimes can be seen with these giant hemangiomas.