 The first lesion we'll talk about is a hemangioma. It's the most common benign liver neoplasm, and it's found in up to 20% of the general population. It's more common in women, and there are different subtypes, including cavernous hemangioma, giant hemangioma, capillary hemangioma, and sclerose hemangioma. The classic cavernous hemangioma is composed of large vascus bases with central cavernous zone. And on the arterial phase, the classic appearance is a peripheral, discontinuous nodular enhancement that is the same enhancement as the blood pool. And then on the venous phase images, we expect to see progressive centripetal fill-in. And depending on the size of the lesion, it may not completely fill on the venous or even the delayed phase images. And here's the same case on cinematic rendering that you can really appreciate the peripheral nodular enhancement pattern on the arterial phase with the centripetal fill-in on the venous phase. And sometimes these hemangiomas can get to be very big, and then they are called giant hemangiomas. And the definitions vary from either greater than four centimeter to up to greater 10 centimeters to be considered a giant hemangioma. Similar to a classic hemangioma on the arterial phase, we expect to see this peripheral, discontinuous enhancement. And because of the sheer size of the lesions, on the venous phase, we expect to see incomplete central fill-in. And here's the lesion again on the cinematic rendering in which we can really appreciate the peripheral nodular enhancement. And we can also play around with the windowing to basically make the central portion of the lesion transparent. So we can look all around and then really appreciate the peripheral nodular enhancement pattern. And with these giant hemangiomas, sometimes the enhancement pattern look a little bit less classic. This lesion, the nodular enhancement on the arterial phase is not quite as peripheral as we are used to seeing it, but at least it's following blood pool attenuation. And then the enhancement pattern as we look through the venous and delayed phase images, it is progressive. So at least that's a reassuring sign. So just keep in mind that when these hemangiomas get to be very big, their imaging appearance may be less typical than what we typically see with smaller hemangiomas. On the opposite end of the spectrum is the capillary hemangioma, also called flash filling hemangioma. And these are small vascular spaces with extensive connective tissues. They account for 16% of all hemangiomas, but 42% of small hemangiomas, less than one centimeter. On arterial phase, we see rapid homogeneous enhancement. And on venous phase, they become isodense to the blood pool. The fourth type of hemangioma is the sclerosed hemangioma, also known as thrombost or hyalinized hemangioma. These hemangiomas have a central fibrotic scar. They may have some punctate calcifications. So they look less classic than the usual hemangiomas. On the arterial phase, you still see that peripheral nodular enhancement, but because the hemangioma is centrally thrombosed, you don't really expect to see complete fill-in on the venous phase. So these sclerosed hemangiomas, they have a more atypical appearance and they can be difficult to diagnose confidently, especially if a patient carries a diagnosis of malignancy. Usually we end up doing MRI. And even on MRI, we may not be sure, but there would be reassuring characteristics, like very T2-bright lesion, the peripheral enhancement with progressive enhancement. So all those are reassuring features, but usually we would end up needing serial follow-ups to be confident about the diagnosis.