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A large MRI-based study published in the journal Radiology highlighted that intermuscular adipose tissue (IMAT), hidden fat stored within muscle groups, serves as a key early biomarker for cardiometabolic (CM) dysfunction.

Researchers found that higher levels of IMAT were associated with hypertension, dyslipidemia, and dysglycemia in individuals without known CM diseases, raising the possibility that routine imaging studies could eventually support opportunistic CM risk assessment.

Systemic Remodeling

“Skeletal muscle is a metabolically active organ, and its remodeling reflects inflammatory disease processes occurring throughout the body,” said Sören J. Backhaus, MD, consultant cardiologist, from the Department of Cardiology at the Kerckhoff Heart Centre in Bad Nauheim, Germany, and member of the Cardiac Magnetic Resonance Imaging Working Group (AG21).

In an interview with Medscape’s German edition, Backhaus emphasized that cardiovascular (CV) disease often begins at an early age.

“Subclinical remodeling of the heart can begin as early as the third decade of life,” he said. “This study shows how early these remodeling processes occur throughout the body.”

The study was conducted by researchers from the Department of Diagnostic and Interventional Radiology, Technical University of Munich (TUM), School of Medicine and Health, Klinikum Rechts der Isar, TUM University Hospital, Munich, Germany.

Sebastian Ziegelmayer, MD, and colleagues analyzed whole-body MRI scans from 11,348 adults enrolled in the German National Cohort, or NAKO who had no known CM disease or major musculoskeletal disorders.

AI-Driven Analysis

Lean muscle mass (LMM) and IMAT were quantified on MRI-based paraspinal muscle segmentations using a deep learning model.

Earlier assessment methods relied on time consuming manual analyses, while the AI-based approach allowed scalable analysis of large imaging datasets.

The analysis showed that the percentage of IMAT increased with age and was higher among women than among men. In contrast, LMM decreased with age and was lower overall in women.

Sex Differences

After adjusting for age, sex, and study center, elevated IMAT was associated with a higher likelihood of hypertension (odds ratio [OR], 1.67), atherogenic dyslipidemia (OR, 1.82), and dysglycemia (OR, 1.49) in both men and women.

Higher LMM was associated with a lower probability of all three CM risk factors, although this association was observed only in men. Overall, participants with higher IMAT and lower LMM showed the greatest prevalence of CM abnormalities.

“It is noteworthy that remodeling involving fat deposition in the muscles and associated proinflammatory processes appear to play a key role in both sexes,” Backhaus said. “LMM alone, however, does not appear to be a suitable marker of these inflammatory processes in women,” said Backhaus.

Hidden Risk

Ziegelmayer and colleagues described analysis of muscle composition as an underused tool for assessing CM risk and called for additional prospective studies. They suggested that “This approach could help identify high-risk individuals who appear metabolically healthy according to conventional criteria, allowing earlier targeted interventions such as exercise and lifestyle modification at an early stage.”

Findings from the NAKO cohort also highlighted the gap between perceived and actual CM health. Despite the absence of known preexisting conditions, approximately 16% of the participants had hypertension, 8.5% had dysglycemia, and nearly half showed evidence of atherogenic dyslipidemia.

Clinical Questions

Whole-body MRI screening is controversial because of concerns regarding overdiagnosis and overtreatment.

Medical experts regularly advise against paying out-of-pocket fees for MRI screening, which has so far been used primarily to detect tumors. “From today’s perspective, we would not perform an MRI scan to screen for CM risk,” Backhaus clarified.

However, researchers have suggested that AI-assisted IMAT and LMM analysis could eventually be incorporated into routine MRI or CT interpretation, allowing clinicians to extract CM information from imaging studies already being performed for other indications.

“Radiology generates a large amount of information that has remained largely unused until now,” Backhaus said. “It would be exciting if this data could be used in the future to provide additional insights into CM health.”

Standards Needed

Backhaus emphasized that considerable work remains before these findings can be incorporated into clinical decision-making.

“In order to use such findings from routine MRIs to guide treatment decisions, we need established cutoff values — and those do not yet exist,” he said.

He also stressed that longitudinal studies are necessary to determine whether IMAT- and LMM-guided risk stratification produces meaningful clinical benefits rather than simply increasing diagnostic testing and overtreatment.

Researchers have concluded that this study adds to growing evidence suggesting that CV disease reflects broader systemic proinflammatory remodeling rather than isolated CV pathology alone. However, they cautioned that IMAT and LMM measurements are not currently ready for routine individualized treatment guidance.

This story was translated from Medscape’s German edition.