2.3. Definition of NAFLD

CT images were obtained with a 128‐row multidetector CT scanner (Siemens, Munich, Germany) using 120 kVp, 0.7 pitch, 5 mm slice thickness and 0.5 s scan time. NAFLD was defined as a liver‐to‐spleen attenuation ratio of <0.9², ³, ¹⁴ or a hepatic attenuation value at least 10 Hounsfield units lower than the spleen attenuation value², ¹⁵ on unenhanced abdominal CT scan. We used average CT attenuation values in four sectors of the liver and the median value from all sections of the spleen (Figure 1). Prevalence of NAFLD was evaluated at 1 month, 6 months and 1 year after PD.

We measured the average computed tomography (CT) attenuation values in four sectors of the liver and the median value from all sections of the spleen on unenhanced CT scans. Nonalcoholic fatty liver disease was defined as a liver‐to‐spleen attenuation ratio of <0.9 or a hepatic attenuation value at least 10 Hounsfield units lower than the spleen attenuation value.