Looking for Trouble
By Beth W. Orenstein
Radiology Today
Vol. 25 No. 1 P. 10

Radiologists Question Benefits of Preventive Whole-Body MRI Scans

A number of start-ups, such as Prenuvo and Ezra, are offering preventive health full-body MRIs. Their promoters say these whole-body MRIs, which take about an hour, can diagnose medical conditions such as cancer early, when they can be treated more successfully and, thus, increase lifespans. However, many in the medical profession believe the scans are harmful and do not help average, low-risk patients. They believe the scans are looking for more trouble than they’re worth.

San Francisco-based Prenuvo offers full-body scans at eight locations in the United States and Canada, with more on the way. Prenuvo says its scans, which can cost up to $2,500, can potentially detect more than 500 conditions, including early-stage tumors and issues such as muscle tears, appendicitis, and fatty deposits in the liver. According to Ezra’s website, the New York-based company offers similar full-body scans in five cities. The company charges $1,350 for a 30-minute full-body scan, $1,950 for a 60-minute full-body scan, or $2,350 for a full-body scan that includes the lungs. Ezra says its scans can detect brain masses, thyroid nodules, pancreatic tumors, gallstones, possible thickened bladders, adrenal gland nodules, and more while these abnormalities are still in their early stages and more easily treated.

In August 2023, when influencer Kim Kardashian posed in scrubs alongside a Prenuvo MRI scanner, calling it a “lifesaving machine,” her Instagram post racked up more than 3.4 million likes. In the last year or so, a number of stories have appeared in newspapers and magazines in print and online detailing how these scans found one early-stage pancreatic tumor in one patient when it was easily treated and a cancerous lung nodule in another who had no symptoms.

The attention and anecdotal stories worry groups such as the ACR and the American College of Preventive Medicine (ACPM). The FDA also does not recommend full-body scans for healthy people. Many radiologists, too, are alarmed by the demand and the large number of curious and concerned patients shelling out big bucks for this technology. To date, no health insurance plan covers these scans because no evidence has been found that they improve health.

Skeptical Societies
In April 2023, the ACR released the following statement: “At this time, the ACR does not believe there is sufficient evidence to justify recommending total body screening for patients with no clinical symptoms, risk factors, or a family history suggesting underlying disease or serious injury. To date, there is no documented evidence that total body screening is cost-efficient or effective in prolonging life. In addition, the ACR is concerned that such procedures will lead to the identification of numerous nonspecific findings that will not ultimately improve patients’ health but will result in unnecessary follow-up testing and procedures, as well as significant expense.” However, the ACR also says it will continue to monitor scientific studies concerning the utility of totalbody MRI screening, suggesting it could revisit its position in the future.

Mizra I. Rahman, MD, MPH, FAAFP, FACPM, the president of the ACPM, says companies such as Prenuvo and Ezra argue that “more screening is better.” Rahman argues that “that’s not necessarily true,” even though the companies have anecdotal evidence of patients whose whole-body scans found asymptomatic cancer or other serious conditions that were highly treatable because they were found early. When performing a whole-body MRI scan, “of course, you will find disease,” Rahman says. However, it is more likely that much of what is found “are just variants of normal” and create unnecessary anxiety in patients. The greatest beneficiaries of whole-body scans, Rahman believes, “are the people who own [the scanners] and promote [the scans] because they collect the fees for doing them.”

Rahman does, however, believe wholeheartedly in preventive screenings. But he cautions that preventive screenings should be done in cases where the scientific evidence shows value and need. “You have to have a certain amount of disease to make screenings worthwhile. For example, we don’t screen women who are in their 20s with mammograms for breast cancer because women under 50 have a decreased risk of the disease. But we do screen women 50 and over because they are at increased risk.”

Until and unless scientifically rigorous studies are done that show there is a clinical benefit to whole-body MRI scans for the general population and that these are cost-effective tests, they shouldn’t be done, Rahman says. “They are really a waste of resources. We all want to live long and healthy lives, but doing more [imaging] doesn’t necessarily mean that will happen.”

False Positives and Negatives
One of the biggest concerns, says Christopher Hess, MD, PhD, chair of the department of radiology and biomedical imaging at the University of California, San Francisco, is that whole-body scans carry a risk of false positives. False positives, he says, can lead to unnecessary and potentially invasive follow-up testing that is costly and anxiety-inducing. A friend of his who recently underwent a wholebody scan called Hess in a panic when her exam showed a possible 2-mm cerebral aneurysm. Fortunately, a repeat MRI scan with higher diagnostic quality showed no aneurysm was present. “The screening MRI in my friend created a need for unnecessary and costly additional testing and led to a great deal of worry over something that wasn’t there,” Hess says.

Hess believes that recent narratives highlighted in the media ignore the dangers of overscreening. “Even when total body scans disclose asymptomatic, incidental cancers or other abnormalities, the discovery doesn’t necessarily lead to better outcomes,” he says. For example, even if his friend had a 2-mm aneurysm, Hess’ vascular neurology colleagues would not have recommended treatment because of its low risk of rupture. “But in her mind, it was a ticking timebomb, and she couldn’t let it go,” Hess says. Often, he notes, when imaging finds something suspicious, the next recommended step is an invasive procedure such as a biopsy, which carries its own risks. “A benign biopsy that causes a complication like a hemorrhage or an infection is no longer benign,” Hess says.

“False negatives are equally difficult to manage,” Hess explains. “An asymptomatic patient with a serious disease that is not detected on a low-quality screening MRI can be falsely assured. Screening MRI is not as good as other techniques we have to detect the most common killers, such as coronary artery disease, breast cancer, colon cancer, and stroke.” He fears that some patients undergoing whole-body scans would consider them a replacement for scientifically backed screening methods, such as mammography for breast cancer and colonoscopy for colon cancer. “When individuals do opt for wholebody screening MRI, they should also be undergoing medical society recommended screenings at appropriate ages and intervals,” Hess says.

Quality Issues
The quality of a whole-body MRI scan is not the same as a diagnostic or screening MRI performed for a specific purpose, Hess says. The whole-body scan is designed to cover more structures rather than provide a detailed evaluation of any specific structure. “So, by necessity, you interpret the results of the exams differently,” Hess says. For safety reasons, whole-body MRI scans do not use contrast, which is needed to obtain the true value of some diagnostic MRIs. Contrast helps detect even the smallest of tumors, and contrast can give the reader more clarity regarding a tumor’s location and size as well as an understanding of which organs or tissues are involved. Scans of the lungs, brain, knee, and prostate all require different techniques for best evaluation, Hess says.

Hess also is concerned that the wholebody MRI screening trend could also introduce patient access issues. Were enough people to opt for whole-body scans as a regular screening, there wouldn’t be enough MRI machines to accommodate everyone. Rahman agrees: If groups such as the United States Preventive Services Task Force, which makes many recommendations about which screenings should be done and at what age and intervals, were to recommend whole-body MRI screenings, “there wouldn’t be enough MRIs available or radiologists available to handle the onslaught of patients.”

Matthew Davenport, MD, a professor of radiology and urology at the University of Michigan, believes the societies’ stance on whole-body screening MRI is quite telling. “If whole-body scans were worthwhile as a screening tool in low-risk patients, respected medical societies would be in favor of performing them,” he says. “Yet, no respected medical society, no government agency, and no payer group supports it. This is true even for organizations that have a potential conflict of interest in favor of additional imaging, such as radiology societies. If I were a patient, I would wonder, why is that?”

Davenport says the most significant concern is the harm stemming from followup care that would become an issue were whole-body MRI screenings to be recommended for a population of people who are not at risk for a specific condition. “The danger in whole-body screening of low-risk patients is the tidal wave of false-positive findings. Those findings will result in more workup, more imaging, more clinic visits, more lab tests, more biopsies, and more operations, all for findings that have a minuscule chance of being clinically important. It’s a tsunami, and, honestly, no system can easily withstand something like that.” The saddest part, Davenport says, is that it would be for no benefit. Any whole-body scan that finds a fast-growing and aggressive tumor where a patient would benefit from early treatment has to be perfectly timed, Davenport says. “And that’s only likely to occur in one in 10,000 tries, or so, I would guess. There is no data to support it.”

Davenport cites a policy change in South Korea in 1999 and sees it as a warning about what can happen when broad screenings are offered to low-risk, asymptomatic patients. That year, seeing a rise in deaths from thyroid cancer, South Korea supported a program to increase ultrasound screening for the disease. The result of the increased screening was a more than six-fold increase in thyroid cancer detection. However, most of the increased detection was for small, indolent tumors that likely would never have caused harm. These patients underwent extensive follow-up testing, biopsies, and, in some cases, operations. Some patients had complications, but analysis showed that the overall death rate from thyroid cancer did not change, Davenport says.

Valid for Surveillance?
As chief scientist for Ezra, Daniel Sodickson, MD, PhD, chief of innovation in radiology and director of the Center for Advanced Imaging Innovation and Research at NYU Grossman School of Medicine, believes that his colleagues in the medical community who object in principle to preventative scans are not looking at them with the proper perspective. When used for “active surveillance” rather than a once-and-done snapshot, they could be of great value, says Sodickson, who works closely with the Ezra Artificial Intelligence team to improve the company’s MRI quality enhancement AIs.

Active surveillance using regular MRI scans, Sodickson says, is already widely accepted in medical circles for populations with known risk of diseases such as prostate cancer or breast cancer. The question is how best to reduce the rate of false positives to extend the same safety net to patients with lower risk.

According to Sodickson, the best way to do this is to combine state-of-the-art scanning methods already used for active surveillance and interpret them in context. Radiologists “tend to think of whole-body MRI scans as one-shot screens, in which a decision must be rendered based on today’s information.” However, Sodickson says, once the whole-body scans are seen as a baseline and repeated for the specific purpose of detecting changes, they could constitute a highly effective early warning system to catch diseases for which no good screening tools currently exist. “In my view,” Sodickson says, “the way to start thinking about full-body MRI is not as a one-shot, yes-or-no test but as a kind of longitudinal monitoring. That’s the best way to rule out false positives—not by doing a full-court press for every uncertain and low-risk finding, but by comparing with previous scans and assessing whether there has been a change.”

Sodickson says using whole-body MRI screenings in this way “requires changing both the way scans are performed and the way they are interpreted.” He agrees that clinical studies are critical to establishing the cost effectiveness of such new approaches. “At the moment, though, given the understandable historical biases against screening, only companies like Ezra are currently performing such studies,” he says.

Sodickson also believes the combination of state-of-the-art scanning and thoughtful interpretation will limit the unnecessary anxiety currently experienced by people such as Hess’ friend who thought she had a brain aneurysm. Rather than being anxiety producing, Sodickson says, whole-body MRI scans of healthy people at regular intervals could be a legitimate way to calm people’s fears when they have reason to otherwise be anxious.

Sodickson says whole-body MRIs can make a real difference for preventive health, but only when they are performed and interpreted correctly. “It is important to remember that medical imaging is not a static technology. It has evolved dramatically over the last 50 years, and it will continue to evolve. In addition to thinking carefully about the limitations of today’s imaging practices, we need to start designing the future of health care, and the future of health care is all about prevention.”

— Beth W. Orenstein of Northampton, Pennsylvania, is a freelance medical writer and regular contributor to Radiology Today.