In March 2024, Yulin Ge, MD, professor of radiology at NYU Langone Health and scientist at the Center for Advanced Imaging Innovation and Research, was among more than 100 people honored by the American Institute for Medical and Biological Engineering (AIMBE) with an induction to the institute’s “college of fellows.” The college counts about three thousand members whom the institute considers “the top two percent of the medical and biological engineering community.” The induction took place at the AIMBE’s annual meeting in Arlington, Virginia, and the institute cited Dr. Ge for “outstanding contributions to the development of imaging biomarkers for neurodegenerative diseases.”
“I think the achievement is related to the passion I have for MRI,” reflected Dr. Ge in a recent interview about his career. “That started in Tiantan, when I saw [early MRI] images—it was amazing.”
It was 1989, and Dr. Ge, who had just earned an MD degree from Shandong University in Jinan, China, embarked on a radiology residency at Tiantan Hospital in Beijing. The hospital had a Fonar β-3000, one of the first commercially available clinical MRI machines, with a field strength of 0.3 tesla (3,000 gauss). The FONAR design, seven years old at the time, was a novelty in China.
“Because we were the first hospital to get that machine, all the doctors from the other parts of China would come to visit for a month or so and study,” recalled Dr. Ge. The demand for expertise in this new imaging modality was so strong that unlike conventional training for newly minted medical doctors, “my residency was actually only MR research,” he said. “It was kind of unique.”
The capability to visualize internal anatomy along several axes and with multiple contrasts opened up new horizons and generated much enthusiasm, especially in fields like neurology and neurosurgery where MRI addressed pressing clinical need. The closest contemporary alternative, computed tomography, produced single-contrast images with little soft tissue detail and only in the axial plane. “You’d have to imagine where the tumor is,” said Dr. Ge. By comparison, “to the surgeons, [MRI] was so beautiful.”
But Dr. Ge’s interest went beyond using the technology to locate tumors and tended toward exploring what else MRI could do. And the more he learned, the more his mentors encouraged him. Tiantan Hospital sent him to the University of California at Los Angeles for a three-month training in anticipation of upgrading to newer scanners. After completing his residency, Dr. Ge was dispatched by the Chinese Medical Association to Kumamoto University in Japan for a neuroimaging studentship with a group led by Mutsumasa Takahashi, MD, a world-renowned luminary in the field of radiology.
“Every week we’d have two [research] meetings at 6:30 in the morning,” recalled Dr. Ge. Simultaneous pursuit of clinical duties and scientific investigations wasn’t so common for radiologists in China, and the discipline of Dr. Takahashi’s team left a deep impression on Dr. Ge. During the six-month fellowship, he contributed to studies on MRI characterization of brain tumors and 3D visualizations of cerebral structures. “They really pushed on the research side,” Dr. Ge said. “I learned a lot.”
In 1998, Dr. Ge visited Philadelphia to attend the XVI International Symposium Neuroradiologicum and the annual meeting of the American Society of Neuroradiology. His poster on a comparison of fast MRI techniques in brain imaging won accolades and earned him a distinction as “symposium scholar.” At that meeting Dr. Ge met Robert Grossman, MD, then a prominent clinician-researcher in the radiology department at the University of Pennsylvania known for investigations into multiple sclerosis. “He asked me whether I was interested to join his group,” recalled Dr. Ge. “I was supposed to actually go back to Beijing to Tiantan Hospital. I talked with my boss … and he said: yeah, go ahead, just to learn more.”
It wasn’t long after joining Dr. Grossman’s group that it became clear to Dr. Ge that there would be no going back. “I saw that there’s a big field, and you can do a lot that cannot be done in China,” Dr. Ge said. In 2001, he followed his mentor and colleague to New York after NYU Langone appointed Dr. Grossman the Louis Marx Professor of Radiology and department chair (in 2007 Dr. Grossman became CEO of NYU Langone and Dean of NYU’s medical school, which is now named after him).
By the mid 2000s, MRI scanner technology had steadily moved toward more and more powerful magnets, with field strengths of several tesla. Dr. Ge was conducting studies with an ultra-high-field 7 T MRI and noticed a distinct pattern of “a lot of small lesions” around cerebral veins of people diagnosed with MS. “Seven tesla can show the veins very well—it’s a combination of high resolution and high sensitivity and susceptibility effects,” he explained. The pattern, reported in 2009 and later confirmed in studies by researchers at other institutions, became known as central vein sign and has proven helpful in diagnosing MS by differentiating it from other demyelinating diseases.
Meanwhile, in a separate investigation using susceptibility-weighted imaging—an MRI method that exploits tissue-specific differences in magnetic susceptibility to create contrast—Dr. Ge and colleagues observed “significantly reduced visibility” of veins in people with MS. Among coauthors of these findings was Mark Haacke, PhD, scientist at Wayne State University who had led the invention of susceptibility weighted imaging, and whom Dr. Ge counts among his closest research collaborators. The team speculated that the apparent disappearance of veins is likely due to weak oxygen uptake in the surrounding white matter but did not have the evidence to rule out other potential causes, such as physical destruction of vasculature or reduced blood flow.
Just a year earlier, Dr. Ge and his longtime colleague and collaborator Hanzhang Lu, PhD, who is now at Johns Hopkins University, developed an MRI technique for quantifying the rate of cerebral oxygen metabolism called T2-Relaxation-Under-Spin-Tagging, or TRUST. The timing could not have been more auspicious, as the technique offered a means to investigate their hypothesis about why fewer veins show up on MRI of MS-affected brains. In a 2012 study, Dr. Ge, Dr. Lu, Dr. Grossman, and others, used TRUST to confirm that in people with MS cerebral tissue consumes less oxygen, leaving more of this element to drain away through the vascular system. (High concentration of unspent oxygen lowers MR signal in the veins, effectively hiding them from MR images.) With these findings, the researchers now had an MRI indicator of early MS. “That’s a cell-activity related marker, a very good functional marker for the brain,” said Dr. Ge.
Today, TRUST is used in scores of medical centers. “The reproducibility is very high and it’s also very quick. At the time, that was a very novel technique,” explained Dr. Ge.
Over the past twelve years, Dr. Ge has accumulated a remarkable record of federal research funding, with the National Institutes of Health awarding more than $20 million to projects he leads as principal or co-principal investigator to develop noninvasive metrics of brain metabolism, search for biomarkers of neurological conditions, and study the mechanisms and effects of aging. “Personally, I like writing grants,” said Dr. Ge. “You have to think of a new hypothesis, a new story, and it also pushes you to think really hard, because getting grants is not easy.”
During a recent interview in his office at NYU Langone, Dr. Ge brought up high-resolution brain images showing hair-thin arteries, work led by a doctoral student he advised named Zhe Sun, who defended her dissertation in September. Dr. Ge, Dr. Sun, and colleagues have developed MRI techniques to visualize microscopic arteries, quantify their “tortuosity” or bendiness, and measure the blood flow within them. The research team discovered that all brain-supplying vessels—from the large carotids in the neck to the smallest medullary arteries deep in white matter—become more twisted with age, like meandering rivers that “after thousands of years of flow gradually create this kind of appearance,” said Dr. Ge. “I think this is the same thing with aging vessels: 2,100 gallons of blood circulate through our system per day, and if you see how far the blood travels, that’s 12,000 miles in our vessels per day, circulating, circulating, circulating.” He hypothesizes that the gradual wear and tear likely contributes to age-related cognitive conditions by diminishing the rate of oxygen supply.
The role of vasculature in neurological health and aging, an area known as vascular contributions to congnitive impairment and dementia, or VCID, has been attracting growing attention among scientists. VCID stems from research on Alzheimer’s disease and was added to the NIH list of critical research areas in 2014; since then, the agency’s funding for the category has risen approximately tenfold. In 2022, Dr. Ge served as president of the International Society for Neurovascular Disease, a group dedicated to advancing the understanding of the circulatory system’s role in neurodegenerative conditions, and he chaired the society’s tenth annual meeting, dedicated to VCID.
“Lifespan has significantly increased in the past century, but healthspan … that’s not really increased so much,” said Dr. Ge. His current work is largely aimed at exploring—and narrowing—the gap between longevity and neurological health. “To look at how normal aging process becomes abnormal, especially in the later part of life … we have several ongoing studies to focus on that area,” said Dr. Ge. “That’s the main focus of my lab right now.”
To sit across from Dr. Ge at his desk as he flicks through high-resolution MRIs of the brain and points out medullary arteries that resemble squiggly cracks in porcelain is not only to see something few have but also to feel the intense enthusiasm that radiates from the man. “When I look at each MR image, I always think: Why is this signal like this? Why is this tissue like this?” he said. “I’m just very into it.”