The “enlarged hilar periportal space sign” in liver cirrhosis

Excerpt

The “enlarged hilar periportal space sign” seen on axial computed tomography (CT) and magnetic resonance (MR) images is a typical finding in patients with liver cirrhosis [1, 2]. In healthy patients, the anterior space of the right portal vein (hilar periportal space) is narrow, containing minimal fatty tissue (Fig. 1a). In patients with early cirrhosis, the hilar periportal space is enlarged and filled with an increased volume of fat, which is a consequence of atrophy of the medial segment (segment IV) of the left liver [1‐4] (Fig. 1b). The exact mechanism of atrophy of the IV segment is not understood fully [3]. However, the most likely cause of this atrophy may be portal venous hypoperfusion based on anatomical variations in blood supply (containing trophic factors) to this segment in liver cirrhosis [1, 2]. Indeed, the portal branches to the segment IV, which arise from the right side of the left portal vein, receive less blood than the veins to the other segments because of the presence of hepatofugal flow [1, 2]. A cutoff value of 10 mm (defined as a distance between the right portal vein and the posterior edge of segment IV) had a sensitivity of 93%, a specificity of 92%, an accuracy of 92%, and a positive predictive value of 91% for a diagnosis of early cirrhosis [1, 3]. The hilar periportal space is therefore deemed enlarged if the distance is greater than 10 mm.

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