Velacur

The Velacur system is a portable ultrasound device designed to non-invasively assess liver health by quantifying tissue stiffness, ultrasound attenuation, and a novel Velacur Determined Fat Fraction (VDFF). It employs shear wave elastography, direct ultrasound attenuation measurement, and combines attenuation with backscatter coefficient for VDFF, supported by machine learning-enhanced guidance tools to aid clinicians in managing liver diseases like hepatic steatosis.

Velacur (Model: LI-1005) is a portable ultrasound elastography system designed for the non-invasive assessment of liver health. Its purpose is to aid in the clinical management of patients with liver diseases, including hepatic steatosis, by providing quantitative estimates of liver tissue stiffness, ultrasound attenuation, and a Velacur Determined Fat Fraction (VDFF). Tissue stiffness is derived from shear wave speed measurements (40-70 Hz), while the VDFF, which is not intended for pediatric use, combines ultrasound attenuation and backscatter coefficient measurements. These metrics are intended for use by trained medical professionals in conjunction with other clinical indicators. The system operates by using an external activation unit, placed under the supine patient, to induce shear waves (at 40, 50, and 60 Hz) within the liver. An ultrasound transducer then performs volumetric scans to measure these waves and tissue properties. Key advancements include the Velacur Determined Fat Fraction (VDFF) algorithm, which combines ultrasound attenuation and computed backscatter coefficient, and machine learning-driven guidance tools: an extended Organ Guide with additional overlays for scan optimization and a Wave Quality Guide to identify optimal shear wave areas. Validation of VDFF against MRI proton density fat fraction (MRI-PDFF) in a 70-patient cohort showed a correlation coefficient of 0.85 and an AUC of 0.97 for detecting ≥5% steatosis. The machine learning algorithms for the Organ Guide and Wave Quality Guide were validated on extensive patient image datasets, achieving Dice Coefficients > 0.7 and high pixel accuracy or sensitivity/specificity, respectively.

AI Regulatory Concerns

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• Q1. How does the Velacur Determined Fat Fraction (VDFF) algorithm specifically combine ultrasound attenuation and backscatter coefficient measurements, and what is the relative weighting or contribution of each to the final VDFF value?; Given the validation cohort for VDFF had a mean BMI of 30.9, how does the device's accuracy for stiffness, attenuation, and VDFF perform across a wider spectrum of BMIs, particularly in patients with severe obesity or very low BMI?; What are the specific anatomical features and optional overlays included in the extended Organ Guide, and how do these quantitatively improve scan optimization or reduce user training time compared to the previous version without these extensions?; The Wave Quality Guide uses Dice Coefficient, sensitivity, and specificity for validation against expert segmentation. How does the system translate these quality metrics into actionable, real-time feedback for the operator to improve image acquisition if wave quality is suboptimal?; While VDFF validation used MRI-PDFF as ground truth, how do the liver stiffness and ultrasound attenuation measurements from Velacur correlate with histological findings from liver biopsy for fibrosis staging and steatosis grading, respectively, within the patient populations described?