 Interseception is a cause of acute pain. It's prolapse of one segment of the bowel of the interseceptum into another and it causes acute pain in early childhood, under three years, 90% are ileocolic. The remainder may be ileocolic or ileo-olio, but this is what you're commonly going to see. 90% are idiopathic and have no leap point and they're just due to hypertrophy of prior patches, small nodes. So typically three months to three years, 10% older children, they have abdominal pain, they have vomiting and bloody stool and this is an interseception, ileum going into colon and the total length is usually 8.5 centimeters and on ultrasound, typically you see it because it's ileum going into the colon and the right abdomen, you're going to see multiple layers, the target sign, the bull's eye sign and if you lay it out you've got the pseudo kidney sign, okay, oh boy it's sort of like a kidney, at least that's what they call it. Here's another one, the target sign, you write abdomen and you'll lay it out, you've got the pseudo kidney sign, that is interseception, turn color on, if the bowel is viable you're going to see lots of color and it's sort of helpful if you're going to go ahead and try to reduce this because it tells you that you've got viable bowel and this is usually reducible. Here's another one, there's no flow, we made an attempt, a reduction it didn't work and that was the scheming bowel at surgery, leap points 10% of patients, more common at older children, the leap points include mechal diverticulum, polyp, hematoma, duplication cyst, and lymphoma and ultrasound you're just going to see a mass and the interseception. Here is the interseception, a multi-layered mass, right abdomen, right upper quadrant, not right lower quadrant, this echogenic part is the mesentery that goes along with the bowel, this is a mass that was a hematoma, this is an interseception, target sign, multiple layers, the echogenic part is the mesentery oementum and this was apollop, here's another interseception, multiple layers, there's an anechoic mass in this interseception that's a duplication cyst. The ultrasound factors that predict that you're going to have difficulty reducing this, if you see absent blood flow, I showed you that, if you have a large amount of fluid and the central interseception it's a bad sign, if you see a lot of trapped lymph nodes in the interseception and if there's a lead mass. Sensitivity 94 to 100% specificity up to 100% occasionally fecal contents, inflammatory bowel disease, hematoma will mimic interseception, this patient had acute pain and we thought maybe that was interseception, did an enema, this turned out to be a colitis and the differential is the other interseception, transient interseception, it occurs in the left upper quadrant, a life through the genome, it's very short compared to the standard interseception which is much larger, it resolves spontaneously and it's only the one lesion, don't touch it, it's going to go away. So, these patients, I had pain, we do look at the right lower quadrant but we also look, as I mentioned in the entire abdomen, if we don't find something in the right lower quadrant, this was in the left upper quadrant, it's a target appearance, it's an interseception, it's small, another one, it's small, those are transient interseceptions, we feel comfortable with that, we leave it alone.