Peritoneal to abdominal height ratio (PAR)
Peritoneal to abdominal height ratio (PAR) ≥ 0.52 is a statistically associated sign for raised intra-abdominal pressure > 12 mmHg in the context of abdominal compartment syndrome in critically ill patients in CT.
It can be calculated by dividing the distance from the linea alba to the posterior aspect of the duodenum (the a.p. peritoneal compartment diameter) by the distance from the linea alba to the posterior fascia excluding the subcutaneous fat (the a.p. abdominal diameter) measured in the midline on axial CT. A ratio equal to or higher than 0.52 and a corresponding clinical context should raise the suspicion for raised intra-abdominal pressure .
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