New regions of interest in body composition analysis by dual energy X-ray absorptiometry: "liver adiposity".

Purpose: Hepatic steatosis is an increasing worldwide metabolic disease and the earliest biomarker for the liver fibrosis development. Thus, its detection and quantification during non-invasive examinations should be always considered as clinically relevant. Our aim was to test new designed regions of interest (ROIs) on whole body images acquired by dual energy x-ray absorptiometry (DXA) in comparison with DXA conventional ROIs and ultrasonography (US) in order to evaluate predictive values on liver steatosis detection and grading. Methods and Materials: Ninety-nine subjects directed to body composition assessment by DXA were prospectively enrolled. All patients were submitted to whole body DXA scan (Lunar iDXA, software enCORE 12.0) and underwent US evaluation on the same day to assess hepatic steatosis (mild-moderate-severe). On every DXA image three new liver-suited ROIs were manually created by a skilled radiologist. Fat mass (FM) and FM percentage (FMp) were investigated on whole body and regionally (android and new ROIs). FM and FMp results were correlated with US Results: Out of 99 patients, 70 (70.7%) resulted affected by liver steatosis on US evaluation (32/70−45.7% mild, 32/70−45.7% moderate and 6/70−8.6% severe). FM and FMp of all ROIs were significantly correlated with presence and grading of steatosis (p < 0.001); however, they were able to predict and to distinguish steatosis absence from moderate and severe grade, but not mild. FMp of one among the new liver-suited ROIs showed the best predictive value for liver steatosis. Conclusion: New ROIs should be included in whole body DXA examinations to provide additional information and higher predictive value on liver steatosis.