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Purpose: It has been reported that the estimate of ultrasound attenuation coefficient (AC) is affected by depth of measurement, with linear decrease of values with depth. It is unknown whether backscatter coefficient (BSC) has similar behavior.
Methods: This retrospective study was performed with Sequoia US system equipped with ultrasound derived fat fraction (UDFF) algorithm (Siemens Healthineers, Issaquah, WA, USA) that combines BSC with AC. UDFF was obtained positioning upper edge of the region of interest at 1.5,2,3,4,5 cm below liver capsule. BSC data were extracted from UDFF offline. A fractional polynomial regression, which selects the best model considering the polynomial development of the variables of interest, was used. Covariates included were age, sex, skin-to-liver-capsule distance, stiffness. Distance was included as linear factor or with a power ranging from - 2 to 3, and the best fitting model was chosen according to partial F test. Body mass index (BMI) was not included because of collinearity with skin-to-liver capsule distance.
Results: 104 individuals (56 females; age: 57.9 ± 13.0 years; BMI: 29.0 ± 6.5 kg/m; skin-to-liver-capsule distance: 2.3 ± 0.7 cm; liver stiffness: 7.5 ± 5.5 kiloPascal) were studied. Best fitting model for BSC included a combination of depth as linear factor and square root. BSC showed a decrease of - 13.98 dB/cm-steradian for each logarithmic increase of 1 cm depth (coefficient: - 13.98; 95% CI: - 21.016; - 5.379; p = .001). Skin-to-liver-capsule distance and stiffness also were independent predictors of BSC.
Conclusions: The estimation of the BSC in the liver exhibits a depth dependence that significantly affects results. A standardized acquisition protocol is needed to compare results and reliably assess changes over time.
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http://dx.doi.org/10.1007/s00261-024-04413-6 | DOI Listing |
Eur Radiol
September 2025
Department of Radiology, Northeastern Ohio Medical University, Rootstown, OH, USA.
Objectives: Methods for measuring the ultrasound attenuation coefficient (AC) vary across different systems. Some have fixed regions of interest (ROI) while others have movable ROIs. Aims were to evaluate whether, using a system with a fixed ROI, correlation between AC and MRI proton density fat fraction (MRI-PDFF), and performance could be improved by (i) reducing fixed ROI length to 30 mm, changing starting point from the transducer, and (ii) using a movable ROI at different depths.
View Article and Find Full Text PDFJ Gastroenterol
June 2025
Division of Hepatobiliary and Pancreatic Disease, Department of Gastroenterology, Hyogo Medical University, 1-1 Mukogawa-cho, Nishinomiya, Japan.
Background: Attenuation Imaging (ATI) and controlled attenuation parameter (CAP) are non-invasive ultrasound-based methods for diagnosing hepatic steatosis. However, reports on the clinical usefulness of ATI are limited. We aimed to compare the ability of ATI and CAP to diagnose hepatic steatosis with magnetic resonance imaging-based proton density fat fraction (MRI-PDFF) as the reference standard.
View Article and Find Full Text PDFUltraschall Med
August 2025
Internal Medicine III, Div. of Gastroenterology & Hepatology, Medical University of Vienna, Vienna, Austria.
Abdom Radiol (NY)
August 2024
Department of Radiology, Northeastern Ohio Medical University, Rootstown, OH, USA.
Dig Liver Dis
March 2022
Division of Gastroenterology, Department of Medicine II, Leipzig University Medical Center, Liebigstrasse 20, 04103 Leipzig, Germany. Electronic address:
Background & Aims: Probe choice (M or XL) in transient elastography can be made by the user's own measure of skin-to-liver-capsule distance (SCD) or with an automated tool (AUTO). We studied how AUTO depends on initial probe choice.
Methods: Three fictive clinics were considered: The "M-first clinic" uses AUTO from the M probe, the "XL-first clinic" uses AUTO from the XL probe and a "reference clinic" measures SCD independently.