 So this next patient is a 29 year old female who is pregnant and has shortness of breath for which a CT scan of the chest utilizing a pulmonary embolism protocol was performed. So we'll scroll down through these images. I'm not going to focus on findings in the chest, but as it turns out, we image a little bit of the upper abdomen here and we see a rather large mass in the rightopatic lobe, maybe some rim enhancement surrounding it. It looks like it has internal complexity to it and for this reason an MRI was performed. So here we have MRI of this patient to evaluate this liver mass because the patient is pregnant, could not give contrast and we had to do sort of an abbreviated sequence for a variety of lesions. But we're going to start off with our T2 weighted imaging sequences to look at this indeterminate liver mass. And on it we can see a rather large mass in the rightopatic lobe. On the T2 weighted images performed without fat saturation, we can see that this lesion has a very interesting appearance. So pretty well defined internally has what I would say is mostly intermediate T2 signals seen throughout most of it over here, for example. But there are discrete clusters of more hyper intense T2 signal seen along the periphery of this mass. On the T2 turbo spin echo, fat saturated imaging sequence, these findings are redemonstrated where we have sort of intermediate signals centrally and more discrete areas of a hyper intense T2 signal along the periphery of this lesion. Also noted is a very, very discrete T2 hypo intense rim that surrounds the majority of this mass, or in fact all this mass, that becomes an important imaging finding in this patient. So we didn't do a lot more sequences for this patient, certainly did not give intravenous contrast, but this imaging appearance is quite characteristic of a particular type of abscess that can inflict the liver. This is known as an echinococcal abscess, and this is a manifestation of hepatic iodated disease. Now this results from infection of certain tapeworms. You have the echinococcus granulosis, which is the most common one, and you have the multi-locularis, which is less common. This tends to be a little bit more aggressive in its appearance. This tends to have an imaging appearance that's quite characteristic of what we're seeing over here. This finding is endemic in certain parts of the world, such as the Middle East, the Mediterranean region, Australia, and New Zealand. So if you see a patient with a mass that looks like this, who either are from one of those countries or visit one of those countries, you've got to be worried about an underlying echinococcal abscess. Humans are the intermediate hosts. Humans ingest the larvae into the GI tract, and then these get transferred to the liver via the portal vein or through other vessels to the systemic circulation. Initially, often patients are asymptomatic, but as this increases in size, you can get pain. And one of the other complications that can occur is rupture. Now these can rupture internally, not affecting the outer portion of the cyst. It can rupture into the biliary tree, and it can also rupture into the peritoneal cavity. And particularly when the latter occurs, you're at risk for anaphylaxis. So that's something that you need to watch out for in these patients. The imaging appearance, as I said, is quite characteristic. Well, you'll have a dominant cystic mass, with a very discrete T2 hypo-intense rim, as can be seen on the fat saturated image. And at the periphery of this, you're going to see multiple, multiple, what we call daughter cysts. And so that's what we're seeing along the periphery of this mass over here. And this finding is characteristic of anachronococcal abscess.