Spiral CT features and anatomic basis of posterior pararenal space involvement in acute pancreatitis

Abstract

Objective To evaluate spiral CT features and anatomic basis of the posterior pararenal space (PPS) involvement in acute pancreatitis (AP). Methods CT images of 87 cases with AP were retrospectively studied with focus on spiral CT features, incidence of the PPS involvement, and its correlations with the posterior renal fascia or lateroconal fascia. Results Our study showed that the incidence of the PPS involvement was 47%(41/87), with Grade A 53%(46/87), Grade B 24%(21/87), and Grade C 23%(20/87), and Grade 0 53%(46/87), Grade Ⅰ 22%(19/87), and Grade Ⅱ 25%(22/87), respectively. The pancreatitis fluid collection in the PPS was continuous with that in the anterior pararenal space or with the fluid between the two laminae of the posterior renal fascia. In 3 follow-up cases, pseudocysts in the PPS were continuous with that in anterior pararenal space below the cone of renal fascia. Conclusion Spiral CT features of the PPS involvement varies from mild inflammatory changes to fluid collection or phlegmonous mass. Fluid within anterior pararenal space in AP flows into the PPS by three routes.