RSNA Scholar Unravels Osteoarthritis Mysteries
Having already helped resolve a longstanding "chicken or egg" question about the relationship between osteoarthritis and joint degeneration, 2004 GE Medical Systems/RSNA Research Scholar Christine B. Chung, M.D., continues her work to demystify the disease's progression.
 Christine B. Chung, M.D.University of California, San Diego |
Central to osteoarthritis is the degeneration of articular cartilage lining the joints in the musculoskeletal system. Articular cartilage is a complex tissue with the deepest layers relatively unexplored through standard commercially available MR imaging. These tissues and their role in cartilage degeneration have been difficult to characterize, as the deepest layers of cartilage have very short T2 magnetic characteristics making them virtually undetectable with MR imaging.
Dr. Chung, an associate professor of radiology at the University of California, San Diego (UCSD), and an internationally recognized musculoskeletal radiology expert, launched her quest to find a way to image these tissues after learning about ultrashort TE imaging (UTE), a new technology introduced at UCSD by her mentor Graeme Bydder, M.B., B.S., F.R.C.R.
Debilitating osteoarthritis affects nearly 27 million Americans, according to the Arthritis Foundation. The incidence of the condition continues to rise as the U.S. population ages and obesity becomes ever more common.
While the excitation and relaxation of protons in more shallow or superficial tissue is visible using MR imaging, technological limitations prevented the deepest layers of articular cartilage—those with very short T2 values, an MR property intrinsic to all tissues—from being detected in the clinical setting prior to the advent of UTE, said Dr. Chung, who also received a 2002 Philips Medical Systems/RSNA Research Seed Grant.
Drs. Chung and Bydder established feasibility data to show that it was possible to use UTE to noninvasively look at the deepest layers of articular cartilage tissue and structural regions. These findings formed the basis for Dr. Chung's 2004 GE Medical Systems/RSNA Research Scholar Grant, "MR Imaging of Patellofemoral and Femorotibial Articular Cartilage: Qualitative and Quantitative Assessment with Ultrashort TE (UTE) Imaging."
"UTE imaging has really opened the door to a whole new level for evaluation of this tissue, which will hopefully lead to our ability to identify degenerative changes in these tissues much, much earlier," said Dr. Chung. "It's really exciting."
Dr. Chung's RSNA research went on to resolve vexing questions about the relationship between joint degeneration and osteoarthritis. At the time, two conflicting theories were being presented in the medical literature about the onset and progression of the disease.
The "outside in" theory suggested that the onset of osteoarthritis was caused by an initial wearing away of the superficial cartilage, which then brought on joint degeneration. An opposing theory hypothesized that an initial injury to the foundation of cartilage—where it meets the bone—destabilized the superficial layers of cartilage, causing degeneration from the inside out.
"Using UTE, we could see lesions or places where the deepest layers of cartilage looked abnormal, but where there was preservation of the superficial layers of cartilage," said Dr. Chung. "These findings not only gave credence to the 'inside out' theory, but also made us want to launch more advanced animal studies where we would place lesions and sequentially see how the degeneration occurs."
Dr. Chung continues to seek funding from the National Institutes of Health (NIH) for this work, recently receiving an R21 grant to use UTE to look at the deep tissues in the meniscus of the temporomandibular joint and the cartilage that lines the articulation of the joint.
"She has taken the traditional strength of UCSD in anatomic-radiologic correlation into the 21st century with these specific musculoskeletal pulse sequences and purpose-designed coils and linked it with biomechanical studies," said Dr. Bydder, a professor of radiology at UCSD. "This regularly results in visualizing structures that have not been seen previously with MR imaging and allows detailed correlation of structure with function at a level not previously possible. It's not hard to see why she is in demand as a lecturer throughout the world both for clinical teaching and her research."
While UCSD Department of Radiology Chair William G. Bradley, M.D., Ph.D., called Dr. Chung "one of radiology's emerging superstars," she maintains that success in today's challenging research environment is a team effort.
"In this day and age, when funding is so hard to obtain, it really takes a united front using every possible source of help that a clinical researcher can get—from professional organizations like RSNA and our radiology departments to our chairs and mentors," said Dr. Chung. "Without each one of these spokes in the wheel it would not have been possible for me to succeed. I was really lucky."
Dr. Chung said she gleans inspiration not only from her clinical work but also from the stimulating and rewarding collaborations with colleagues committed to supporting the scientific mission of fact finding and solving questions.
"We don't just do it by ourselves," said Dr. Chung.