L.V. Sharipova1, Z.F. Badrieva2, M.V. Lukin3, V.A. Fokin4, E.A. Brui5, A.V. Shchelokova6

1,2,5,6 ITMO University (St. Petersburg, Russian)
3,4 Almazov National Medical Research Centre (St. Petersburg, Russia)
1 lv.sharipova@yandex.ru, 2 badrievaz@gmail.com, 3 lukin.mv.radiology@gmail.com, 4 vladfokin@mail.ru,
5 e.bruy@metalab.ifmo.ru, 6 a.schelokova@metalab.ifmo.ru

Cardiac magnetic resonance imaging (MRI) at 3 T offers high diagnostic potential. However, the specificity of this magnetic field is that the electromagnetic wavelength in tissues becomes comparable to the dimensions of the human body, leading to interference effects (standing waves) and, consequently, spatial inhomogeneity of the radiofrequency (RF) magnetic field. This results in reduced image quality, the appearance of artifacts, and inaccuracies in quantitative measurements, particularly in myocardial T1-relaxation time mapping. These factors limit the diagnostic value of the method, necessitating the search for effective ways to address them. Dielectric pads partially solve this problem, but they are heavy, expensive, and suffer from material property degradation over time. Metasurfaces are free from these drawbacks and have proven effective in MRI of other anatomical regions. However, their potential for improving cardiac MRI quality remains unexplored.

To investigate the potential of using metasurface‑based pads to improve quantitative parameters of cardiac MR images.

Numerical simulations using a human body model show that placing two metasurface-based pads above and below the chest near the region of interest reduces the coefficient of variation of the B1 field amplitude over the heart region from 20% to 13% and increases SAR efficiency by 25%. In vivo experiments on 20 healthy volunteers (mean age 26 years) using a 3 T scanner and the MOLLI sequence demonstrated a statistically significant twofold increase in the signal-to-noise ratio with pads (p < 0.00001). Moreover, the variability of T1 relaxation times within the myocardium (interquartile range) decreased from 129±79 ms to 87±36 ms (p = 0.02), indicating improved T1 mapping accuracy. The obtained median T1 values (1061–1114 ms) agreed with published data for healthy myocardium at 3 T.

The use of metasurface-based pads improves quantitative cardiac MRI parameters and enhances image quality across different patient groups, thereby increasing diagnostic accuracy in clinical practice when performing studies on high-field MRI systems. The lightweight (tens of grams) and flexible design of the metasurface pads ensures patient comfort and ease of integration into existing clinical workflows without requiring hardware modifications. Furthermore, the pads can be easily customized to individual patient anatomy, potentially reducing scan time and improving throughput. The proposed technology is particularly relevant for MRI systems not equipped with active RF shimming capabilities.

Sharipova L.V., Badrieva Z.F., Lukin M.V., Fokin V.A., Brui E.A., Shchelokova A.V. Metasurface-based pads to improve quantitative cardiac MRI parameters // Biomedicine Radioengineering. 2026. V. 29. № 4. P. 23–35. DOI: https:// doi.org/10.18127/ j15604136-202604-03

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