Quantitative Ultrasound To Diagnose Nonalcoholic Fatty Liver Disease in Children.

SUMMARY Our broad long-term objective is to improve the health of children with nonalcoholic fatty liver disease (NAFLD), a condition characterized by accumulation of fat in liver cells, by developing and validating accurate, precise, practical, and widely available tools to detect, measure, and monitor liver fat. Over 5 million American children

have NAFLD, placing them at risk for type 2 diabetes, cirrhosis, and premature death. Addressing this health crisis is crucial for our nation. Clinical practice guidelines recommend screening for NAFLD in American children aged 9 to 17-years with overweight or obesity because early diagnosis, prompt specialist referral, and NAFLD-

tailored management can improve outcomes. However, there is no accurate, precise, practical, and widely available diagnostic tool to implement these guidelines, a major unmet need in pediatric NAFLD. Quantitative ultrasound (QUS, US) holds promise to address this unmet need, but notable gaps in QUS technology persist:

Gap 1) unsatisfactory accuracy of current commercial QUS methods for estimating liver fat content in children; Gap 2) availability of commercial QUS technology mainly on full-size (US) systems, primarily located within radiology departments, limiting access for many children at risk NAFLD; and Gap 3) poor cross-vendor

reproducibility, which undermines utility. Our immediate goal is to address these gaps by developing advanced QUS analysis models for use with full-size US or inexpensive POCUS systems in children at risk for NAFLD to estimate liver fat fraction and classify presence/absence of fatty liver. The models will incorporate technical

innovations to improve QUS accuracy and efficiency. To develop and test these models, we propose a cross- sectional accuracy and precision clinical study in 140 children (ages 9 to 17-years) suspected to have NAFLD, who will undergo full-size US and POCUS exams with contemporaneous MRI-proton density fat fraction as

reference. Our three specific aims are: Aim 1. To improve accuracy of QUS on full-size US for liver fat assessment in children. Aim 2. To translate QUS liver fat assessment in children to POCUS. Aim 3. To improve cross-vendor reproducibility of QUS liver fat assessment in children. We hypothesize that our QUS models using

either full-size US or POCUS will estimate liver fat content more accurately than other US methods. We also expect our models to classify presence/absence of fatty liver in children more accurately than other US methods. Exploratory aims are to: a) explore associations between QUS and histology; b) explore effects of potential

confounders on accuracy and precision of QUS models; c) create a repository of US data, plasma, and digitized histology for future research. Impact: Achieving our study aims will enable multi-center, multi-vendor trials, which collectively have the potential to transform clinical practice and therapeutic discovery in children by enabling

widespread dissemination of reliable, practical, and generalizable diagnostic solutions for pediatric NAFLD.