PROJECT SUMMARY
Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the U.S. and ranges
from simple fatty liver (or non-alcoholic fatty liver, NAFL) to the progressive form, non-alcoholic steatohepatitis
(NASH). About 20-30% of subjects with NAFL develop NASH, which is caused by hepatocyte injury, hepatic
inflammation, and resultant hepatic fibrosis. NASH can lead to life-threatening conditions, but is difficult to
diagnose at early stages. Liver biopsy is the current standard to diagnose NAFL/NASH, but biopsy is invasive,
has associated morbidity, and is limited by sampling errors and inter-observer variability. Many patients
present with later stage NASH, adversely impacting outcomes and healthcare costs, which are estimated at
$32 billion annually in the U.S. Magnetic resonance imaging (MRI), including elastography (MRE), is a
technology that can non-invasively quantify hepatic fat (MRI proton-density fat fraction), iron overload (MRI
R2*), and fibrosis (MRE stiffness). However, current liver MRI is challenged by motion artifacts and incomplete
signal models, which can compromise the accuracy and reproducibility of the quantitative parameters derived
from them. In addition, early tissue changes associated with NASH are not adequately characterized using
conventional MRI. The common requirements of breath-holding and long protocols also severely limit the
adoption of liver MRI in the clinic. Furthermore, the present clinical interpretation of MRI has limited ability to
distinguish NASH from NAFL. The research teams at the University of California Los Angeles, University of
Arizona, and Siemens have been leading the development of motion-robust radial MRI to quantify hepatic
PDFF and R2*, T2 and T1, perfusion, and stiffness. The Siemens team has also developed deep learning
methods for medical image processing and disease detection and classification. In this bioengineering
research partnership project, the multi-disciplinary research team will investigate four aims: (1) Develop a
robust motion compensation framework for free-breathing multi-parametric quantitative radial liver MRI; (2)
Accelerate quantitative liver MRI scans through combined acquisition and joint modeling of multiple
parameters, data undersampling, and deep learning-based reconstruction and quantification; (3) Develop deep
learning models to accurately classify NAFL versus NASH and measure the degree of fibrosis based on
quantitative MRI; (4) Prospectively assess the new quantitative MRI and deep learning technologies for
classifying NAFL versus NASH and measuring fibrosis in patients, with respect to liver biopsy. The new free-
breathing quantitative MRI and deep learning technologies developed in this project will accurately classify
NAFL versus NASH and measure fibrosis using data from the entire liver and thus help to avoid liver biopsy,
allow monitoring of treatment responses, and accelerate the development and implementation of new
therapies.