Round belly sign (abdominal compartment syndrome)
Round belly sign is a sign of increased abdominal pressure of greater than 20 mmHg in abdominal compartment syndrome where the abdomen has a rounded appearance of transverse section on CT, rather than its typical oval shape.
The sign is positive when the AP to transverse diameter of the abdomen (abdominal ratio) is >0.80 1. To measure the ratio, the maximal anteroposterior abdominal diameter (AP) and transverse abdominal diameter (TV) are measured on a transverse image of the abdomen at the level of the left renal vein crossing the abdominal aorta. Subcutaneous fat is not to be included in the ratio. The abdominal ratio is AP/TV (see figure 1) and should normally be <0.80.