Case 2 Answer:

This is a case of perforated appendicitis.  The hyperdense structures on the images are appendicoliths; of which, this little guy had two.  Remember to always look for the appendix on every case even though it's not a standard field in our templates.  This serves two purposes - one, it's good for the patient. Secondly, it helps you get better at finding the appendix. I start with the axial images and, if I can't find it, I find the coronal to be very helpful in locating it. If I can't find it on soft tissue windows, using the lung windows will often help the appendix stand out.

This little guy had a frank perforation, which can be seen as mucosal discontinuity on the coronal images. You can also see a periappendiceal abscess (arrow on the axial; star on the coronal images). The last image was not present on the original case. However, I included it because it shows a second abscess, distant from the appendix, in the upper abdomen with reactive jejunitis of the proximal jejunum.

Periappendiceal abscess

Rounded mucosal layer is enhancing with an intraluminal appendicolith

Blunt ending, tubular structure, which is the appendix.  You can see the mucosal discontinuity with adjacent fluid collection/abscess.

Star - abscess

Second abscess in the epigastric region. The arrow is demonstrating reactive wall thickening of the proximal jejunum (a reactive jejunitis)