OBJECTIVE: To evaluate the relationship between the magnetic resonance imaging-derived proton density fat fraction (MRI-PDFF) and liver size in patients with metabolic dysfunction-associated steatotic liver disease (MASLD), as well as to explore the role of determining the craniocaudal diameter of the right hepatic lobe (CCDHL), measured at the midclavicular line, and liver volumetry as complementary tools in the assessment of hepatic steatosis.
MATERIALS AND METHODS: This was a single-center, cross-sectional, prospective study including 289 patients with MASLD who underwent multiparametric MRI for the evaluation of hepatic steatosis, which was categorized by the MRI-PDFF value. Liver size measurements included the CCDHL, liver volume from automated segmentation, and its difference from the total expected liver volume (eLV), calculated with the Vauthey formula.
RESULTS: A significant positive correlation was observed between the MRI-PDFF and liver size measurements, including the CCDHL (rs = 0.651; p < 0.001) and the eLV (rs = 0.568; p < 0.001). Patients with higher grades of steatosis showed a progressive increase in liver volume (p < 0.001). A receiver operating characteristic curve analysis demonstrated good diagnostic accuracy for the CCDHL and for the eLV in identifying moderate-to-severe steatosis (area under the curve: 0.76 and 0.83, respectively).
CONCLUSION: The integrated assessment of the MRI-PDFF and liver size appears to be effective for the diagnosis, stratification, and monitoring of steatosis in patients with MASLD.

Keywords: Fatty liver; Multiparametric magnetic resonance imaging; Biomarkers; Liver/diagnostic imaging; Liver/physiopathology.