Blood vessel effects in quantitative ultrasound attenuation and backscatter Free

Nonalcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease worldwide. Current diagnosis relies on invasive biopsy. Quantitative ultrasound (QUS) may provide a noninvasive alternative, using parameters such as attenuation (AC) and backscatter (BSC) coefficients. This study examines how exclusion of larger blood vessels from fields of interest (FOI) affects AC and BSC measurements in NAFLD patient livers. 201 total participants with known or suspected NAFLD underwent liver right lobe QUS. Of these, 84 underwent a second QUS exam on the same day and 172 patients had contemporaneous MRI with computation of proton density fat fraction (MRI-PDFF). AC and BSC were calculated from FOIs drawn on reconstructed B-mode images in two ways: FOIs that included as much of the liver as possible including blood vessels and FOIs modified manually to exclude larger blood vessels. Compared to blood vessel-exclusive FOIs, blood vessel-inclusive FOIs provided higher (<0.005) between-exam ICCs (AC, 0.715 vs 0.864; BSC, 0.685 vs 0.796). Spearman's correlation with MRI-PDFF was (AC, 0.422 vs 0.481; BSC, 0.653 vs 0.596). Results suggest that excluding vessels from FOIs makes QUS measurements less repeatable, although relationship with MRI-PDFF did not favor either FOI. [No. R01DK106419.]