Magnetic resonance elastography (MRE) is an MRI-based technique for quantitatively imaging the mechanical properties of tissue, first described in 1995 [1]. MRE is now widely used in clinical practice, where it is regarded as the most accurate non-invasive method for diagnosing liver fibrosis [2]. It has replaced liver biopsy for this purpose for thousands of patients every year and as of 2022, MRE is deployed on more than 2000 MRI systems globally.
The timeline of this technology, from initial invention to wide clinical use, was affected by many factors, including:
- Pace of algorithm development
- Hardware engineering
- Identifying best applications
- Gaining early evidence
- Obtaining early clinician buy-in
- External validation
- Converting from prototype to product
- Relationships with MRI OEM’s
- Standardization
- Specialty society buy-in
- Pharmaceutical trial applications
- Medical politics and economics
- Patient advocacy
The first successful application of MRE for assessing liver stiffness in vivo was presented at the 2004 annual meeting of the ISMRM and preliminary results showing the ability to discriminate between healthy and fibrotic liver in vivo were presented at the ISMRM meeting in 2005 [3,4]. The decade-long delay from initial description of MRE and successful application for liver imaging was due to the time needed to develop suitable driver technology for generating shear waves in the liver. Within a year after that, published evidence was indicating that liver stiffness measured with MRE is an excellent biomarker for detecting and staging liver fibrosis [5-9].
By 2006, MRE was installed on multiple MRI scanners on the Mayo Clinic Rochester campus as well as Mayo Clinic facilities in Arizona and Florida for full scale clinical testing. The technology was shared at no cost with collaborators at six other academic institutions in the US and Europe. These collaborations accelerated the clinical evaluation of the technology.
By 2007, hepatologists at Mayo Clinic had concluded that MRE was a reliable alternative to liver biopsy for diagnosing liver fibrosis. Given the strong demand for the technology from Mayo Clinic physicians and the benefits to patients, Mayo Clinic founded a company (Resoundant Inc.) in mid-2007 to serve as a low-cost source of regulatory-compliant MRE driver systems for global use by the MRI OEM’s and to provide licensing and technical assistance in implementing MRE technology on their systems.
In 2009 a major MRI OEM obtained FDA clearance for MRE as an add-on for MRI systems. With growing demand for the technology, other major MRI OEM’s incorporated MRE in the following years. All regulatory approved commercially available versions of MRE use similar acquisition techniques and shear wave driver systems, and identical processing technology. In 2018, the Quantitative Imaging Biomarkers Alliance (QIBA) published the first Consensus Profile for Liver MRE, which is a widely recognized standard for using the technology [10].
In 2018, the American College of Radiology successfully sponsored an application to the American Medical Association (AMA) for assignment of a Category 1 CPT code (#76391) for MRE. Subsequently, CMS assigned a value to the service, a necessary prerequisite for government and private reimbursement. The role of MRE in clinical care of patients with chronic liver disease has been now well established in meta-analyses and recognized in clinical guidelines developed by several organizations [11-14].
This presentation will highlight the following strategies in the journey from invention in MRE to standard-of-care:
- Make sure that you are addressing a real problem
- Work with clinical colleagues
- Recognize the ability of student to contribute
- Deploy and seek validation in clinical practice
- Strive to disseminate
- Freely share
- Plan for standardization from the beginning
- Engineer the diagnostic process from end-to-end
- Engage available institutional tech transfer expertise
- Proactively manage conflicts of interest
- Harness the power of convergence science / Pasteur’s Quadrant.