Fully Automated High-Throughput Quantitative MRI of the Liver

The overall purpose of this work is to develop, implement and test a "single-button push", integrated combination of innovative MRI solutions to enable low-cost quantitative evaluation of chronic liver disease in less than 5 minutes of true MRI suite time. The aim is to design a reliable, low variability, fully automated, highly efficient MRI exam.

The primary objective is to demonstrate a free-breathing 2D CSE-MRI method that is robust to motion and free of bias when compared to the reference 3D CSE-MRI method.

Secondary objectives include optimization of the methods in healthy volunteers, and technical success and throughput of the single-button push exam:

1. Repeatability: we will calculate the squared difference between each pair of repeated proton density fat fraction (PDFF) / R2* measurements, and will model this value including the acquisition/reconstruction method as a covariate using Generalized Estimating Equations (GEE)
2. Reproducibility of the proposed method between 1.5T and 3T using the reproducibility coefficient and interclass correlation coefficient (ICC)
3. Technical success of the single-push button exam (completion of exam, acceptable automated prescription as determined through radiologist evaluation, image quality, and automated analysis accuracy compared to manual analysis)
4. Mean and standard deviation of total two-door suite time for the single-push button exam

Specific Aims:

Aim 1: Develop and optimize motion-insensitive, high-SNR (signal-to-noise ratio), free-breathing "error-proof" CSE-MRI for accurate and precise measurement of PDFF and R2* as biomarkers of liver fat and iron.

Aim 2: Confirm the accuracy (ie: bias) and precision (ie: repeatability, and reproducibility across field strength) of the proposed CSE-MRI method in patients with liver steatosis and in patients with liver iron overload.

Aim 3: Implement and validate an integrated single-button push, fully automated CSE-MRI protocol in < 5 minutes of MR room time, using i) Artificial intelligence (AI)-based automated image prescription, ii) an innovative MRI "Smart Suite" design, and iii) automated quantitative image analysis and reporting.

To accomplish these aims, participants will be recruited for 6 substudies:

1. Substudy 1: Optimization of free breathing 2D CSE method in healthy volunteers
2. Substudy 2: Validation of free breathing 2D CSE method in healthy volunteers
3. Substudy 3: Validation in patients with known or suspected iron overload or fatty liver
4. Substudy 4: Evaluation of auto-prescription in healthy volunteers
5. Substudy 5: Round-robin evaluation of single-push button exam in healthy volunteers
6. Substudy 6: Throughput evaluation in patients scheduled for clinical abdominal MRI

For substudies 1, 2, and 4 participants will be asked to complete one research visit lasting approximately 1.5 hours. Participants will be scanned at a single field strength for up to 1 hour. To assess test-retest repeatability, subjects may be asked to sit up on the MRI scanner bed, or step off then back on to the scanner.

In substudy 3, participants will be asked to complete one research visit lasting approximately 1.5 hours. Participants will be scanned on a 1.5T system for up to 1 hour. In order to demonstrate the reproducibility across field strength of CSE MRI to measure liver iron and fat, 10 participants with liver fat and 10 participants with liver iron will be scanned a second time on the same day at 3T. For these 20 participants, total scan time be less than 2 hours and the study visit will last approximately 3 hours.

In substudy 5, the study visit will last approximately 3.5 hours. Participants will participate in groups of 10. After consenting, MRI screening, and anthropometric measurements, participants will form a queue and be scanned consecutively. After scanning, each participant will rejoin the end of the queue. Each participant will be scanned 3 times. Each individual scanning "session" will last approximately 5 minutes, and each participants total scan time will be less than 20 minutes.

Each participant in substudy 5 will be equipped with a Smart Suite RFID (radio frequency identification) or Bluetooth bracelet system to track MRI suite time for each participant and scan. The bracelets are also used in clinical imaging visits to track patient workflow. The bracelet will be used to track when participants enter and leave the MRI suite. The relative timings from baseline will be recorded automatically, entered into the study RedCap and linked with other study data via the participant's Study ID.

For substudy 6, prior to their clinical exam, participants will be scanned with the single-button push protocol. The research scan time will be less than 10 minutes and the total research visit will last approximately 20 minutes. Each participant in this substudy will also be equipped with a Smart Suite RFID or Bluetooth bracelet system to track MRI suite time for each participant and scan, as described for substudy 5.