AP radiograph of the right femur was unremarkable. Coronal STIR MRI of the right hip and femur was unremarkable aside from incidental bright pelvic free fluid noted just above the bladder. Coronal 2D reconstruction from a CT with IV and oral contrast of the abdomen shows a large complex fluid collection containing air and a central calcification in the right lower quadrant which was lying next to the psoas muscle.
The diagnosis was perforated appendicitis with an abscess containing an appendicolith.
Pediatric Imaging 