Liver spontaneous hypoattenuation on CT is an imaging biomarker of the severity of acute pancreatitis

The purpose of this study was to evaluate the relationship between liver spontaneous attenuation (LSA) on computed tomography (CT) reflecting the degree of steatosis, and the severity of acute pancreatitis (AP).All consecutive patients admitted from December 2014 to September 2020 for an episode of AP were retrospectively reviewed. LSA was evaluated on early CT examination and all abdominal CT examinations were reviewed by two abdominal radiologists. Severity of AP was categorized using Atlanta classification and CT severity index. Univariable and multivariable statistical analyses were performed.A total of 467 patients were included. There were 297 men and 170 women, with a mean age of 57 ± 19 (SD) years (range: 18-98 years). Among them, 236 patients (51%) had acute biliary pancreatitis, 134 (29%) had acute alcoholic pancreatitis and 97 (20%) had AP due to other etiologies. A total of 44 (9%) patients had severe AP and 423 (91%) had non severe AP. Median LSA was significantly lower in patients with severe AP (36 Hounsfield units [HU]; interquartile range [IQR]:18; 54) than in patients with non-severe AP (45 HU; IQR: 35; 51) (P < 0.001). In patients with alcoholic AP, median LSA was significantly lower in patients with severe AP (29 HU; IQR: 3; 43) than in those with non-severe AP (42 HU; IQR: 27; 50) (P = 0.022). At multivariable analysis, the third and fourth quartiles of liver spontaneous attenuation values (i.e., < 45 HU/>30 HU and < 30 HU) were independently associated with severe AP (OR, 3.23; 95% CI: 1.33-51.2; P = 0.038 and OR, 8.82; 95% CI: 1.91-69.7; P = 0.014; respectively).LSA on CT is associated with clinical severity of AP and may be used as an additional marker of disease severity.