Coupling Medium Research Articles

Preparation and Evaluation of Polymer-Based Ultrasound Gel and Its Application in Ultrasonography.

Ultrasound imaging is a widely used technique in every health care center and hospital. Ultrasound gel is used as a coupling medium in all ultrasound procedures to replace air between the transducer and the patient’s skin, as ultrasound waves have trouble in traveling through air. This research was performed to formulate an inexpensive alternative to commercially available ultrasound gel as it is expensive and imported from other countries. Different formulations with different concentrations of carbopol 980 (CAR 980) and methylparaben were prepared with natural ingredients such as aloe vera gel and certain available chemicals that have no harmful effects on the skin. To justify the efficiency of the formulations; necessary physicochemical characteristics such as visual clarity, homogeneity, transparency, skin irritation, antibacterial activity, pH, stability, spreadability, conductivity, acoustic impedance, viscosity, and cost were evaluated. Moreover, a comparison study was also conducted with commercially available ultrasound gel that was utilized as a control. All samples showed excellent transparency and no microbial growth. S1 was the only formulation that met all of the requirements for commercial ultrasound gel and produced images that were similar to those produced by commercial ultrasound gel. So, this formulation could be used as an alternative to expensive commercial ultrasound gel for taking images in hospitals and medical centers.

К вопросу об интерпретации эхограмм при контактном способе акустического контакта

The echogram of the ultrasonic pulse flaw detector with the contact testing technique is considered as a convolution when a transducer with a protector matched with the coupling medium receives an acoustic pulse emitted by it through the coupling medium into the load, reflected from it, and from this transducer. A method for calculating echograms for products, transducer, contact gaps (layers) made of any materials, with any value of the contact layer, provided that the acoustic resistances of the materials used are known, is proposed. A method of compensation of interfering reflections for a transducer matched with a coupling medium is proposed. Keywords: u.s. transducer, convolution, reconstruction, interference, sensitivity, resolution, wear plate, contact testing technique.

A Compact Slot-Loaded Antipodal Vivaldi Antenna for a Microwave Imaging System to Monitor Liver Microwave Thermal Ablation

This study presents the design and the experimental validation of a slot-loaded antipodal Vivaldi antenna. The intended use is in an array configuration for monitoring liver microwave thermal ablation by way of microwave imaging (MWI). To optimize electromagnetic power transfer to the human abdomen, the antenna was designed to operate in a coupling medium. The final design has overall dimensions of 40mm×65mm, and the working bandwidth goes from 600 MHz up to 3 GHz, with the possibility to operate at higher frequencies, also. The antenna proposed in this study shows the most compact aperture dimension, as compared with other antennas designed for biomedical applications, working within the same bandwidth. To experimentally evaluate the antenna performances, the coupling medium was realized, proposing a recipe made by low cost, and easy to provide and use, materials. In particular, a mixture of water, oil, dishwashing detergent, and guar gum was used. The realized material showed dielectric properties close to the target ones, proved stability on a 1-week time, and reproducibility against different realizations. The antenna’s measured S-parameters well agreed with the simulation result. When locating two antennas in close proximity, as in the MWI array configuration, the results showed good performances towards mutual coupling.

Design of leakage monitoring system based on optical fiber side coupling effect

Aiming at the problems of the existing quasi-distributed optical fiber sensing measurement technology, such as complexity, low accuracy and slow response time, a quasi-distributed optical fiber water leakage monitoring system with high real-time performance and lower cost is designed; the system is mainly composed of sensitive detection. It is composed of needle, low light detection unit, main control unit and data transmission unit. The lateral coupling effect forms a series of sensing probes after the LED light source is scanned. Light enters the polymer fiber through the lateral coupling structure. When the medium between the LED and the coupling structure changes, the coupling light intensity increases, and the output light intensity at both ends of the fiber increases accordingly, so the liquid leakage event can be converted into a coupling medium change To measure and cooperate with several other modules to complete the construction of a water leakage monitoring system; the results show that the designed fiber-optic water leakage monitoring system has the ability to detect and locate water leakage signals, and the positioning accuracy is less than or equal to 10 cm. Basically realize the functions of liquid leakage detection and leakage point positioning, which conforms to the characteristics of quasi-distributed measurement.

Calcium-Modified Silk Patch as a Next-Generation Ultrasound Coupling Medium.

There is an increasing interest in developing next-generation wearable ultrasound patch systems because of their wide range of applications, such as home healthcare systems and continuous monitoring systems for physiological conditions. A wearable ultrasound patch system requires a stable interface to the skin, an ultrasound coupling medium, a flexible transducer array, and miniaturized operating circuitries. In this study, we proposed a patch composed of calcium (Ca)-modified silk, which serves as both a stable interface and a coupling medium for ultrasound transducer arrays. The Ca-modified silk patch provided not only a stable and conformal interface between the epidermal ultrasound transducer and human skin with high adhesion but also offered acoustic impedance close to that of human skin. The Ca-modified silk patch was flexible and stretchable (∼400% strain) and could be attached to various materials. In addition, because the acoustic impedance of the Ca-modified silk patch was 2.15 MRayl, which was similar to that of human skin (1.99 MRayl), the ultrasound transmission loss of the proposed patch was relatively low (∼0.002 dB). We also verified the use of the Ca-modified silk patch in various ultrasound applications, including ultrasound imaging, ultrasound heating, and transcranial ultrasound stimulation for neuromodulation. The comparable performance of the Ca-modified patch to that of a commercial ultrasound gel and its durability against various environmental conditions confirmed that the Ca-modified silk patch could be a promising candidate as a coupling medium for next-generation ultrasound patch systems.

Fabry–Pérot interference principle-based non-contact thermoacoustic imaging system for breast tumor screening

Microwave-induced thermoacoustic imaging (MTAI) is a potential nonionizing candidate for breast tumor detection due to its high contrast of tissue dielectric absorption and high resolution of ultrasonography. However, conventional MTAI systems need to contact the imaging targets through the ultrasound-coupling medium for the efficient transmission of thermoacoustic signals. This is a major drawback for potential applications such as navigation of open surgeries, burns, and ulcer testing. In this paper, we report a Fabry–Pérot (FP) interference principle-based non-contact thermoacoustic imaging system (NCTAIS). The system can infer the ultrasonic intensity by detecting the changes of the acoustically induced refractive index in the FP cavity. The miniaturized FP interferometer with a diameter of 5 mm achieves outstanding imaging sensitivity with a frequency response up to 1 MHz. An adaptive Stolt migration-based imaging reconstruction algorithm is proposed to solve the MTAI image distortion caused by the significant difference in sound velocity between air and a biological tissue. The NCTAIS is capable of achieving an axial resolution of 0.95 mm and a lateral resolution of 1.91 mm. The technical feasibility for breast tumor screening is validated with an in vitro simulated breast tumor model. The results demonstrate that the proposed NCTAIS offers high imaging sensitivity, high contrast, and deep imaging depth and will have more application scenarios than the conventional MTAI system, requiring the ultrasonic coupling medium to contact ultrasonic transducers.

Enabling multi-input, multi-output measurements with a fluidic transducer

Ultrasonic testing is a widely used method for detecting damage and material characteristics in fields ranging from medicine to aerospace applications. The use of air-coupled ultrasound (ACU) enables an increase in testing speed, since no coupling medium needs to be applied to the transducer-specimen interface at each measurement point. The time needed for testing can be further decreased by using multiple-input, multiple output (MIMO) measurement systems. These systems require the ultrasonic signals to be uncorrelated so the that the individual pulses can be discriminated. Recently, the fluidic transducer was introduced, which generates acoustic pulses in the low ultrasonic frequency range. Experimentally, it is shown that each pulse contains a unique phase signature, that can be extracted by removing the signal envelope information. This technique is used to uniquely discriminate between simultaneously triggered pulses from two fluidic transducers and measure their individual times of flight.

Liquid Leakage Sensor With a V-Shaped Defect Coupling Structure Based on Polymer Optical Fibers

In this study, a novel high-reliability liquid leakage sensor with a V-shaped defect coupling structure (VDCS) is proposed and experimentally demonstrated using polymer optical fibers (POFs) based on a light-emitting diode (LED) side-coupled light source. Liquid leakage detection is achieved with changes in the refractive index as the coupling medium transforms from air to liquid. The LED lamp both provides a light source and assists positioning. The coupling efficiency of the POF liquid leakage sensor varies with the depth and angle of the VDCS. Experimental results show that the coupling efficiency of the POF leakage sensor is high when the VDCS depth is 0.5 mm and the inclination angle is 60°. Compared to an existing leakage sensor with a hole-shape defect coupling structure (HDCS), the VDCS has a faster response time and higher reversibility. The average reliability of the liquid leakage sensor is increased to 5.92 μW/mL. This research provides a powerful structural reference for POF side-coupling leak measurement and can also be applied to the fields of gas and humidity sensing.

Enhanced Absorption with Graphene-Coated Silicon Carbide Nanowires for Mid-Infrared Nanophotonics

The mid-infrared (MIR) is an exciting spectral range that also hosts useful molecular vibrational fingerprints. There is a growing interest in nanophotonics operating in this spectral range, and recent advances in plasmonic research are aimed at enhancing MIR infrared nanophotonics. In particular, the design of hybrid plasmonic metasurfaces has emerged as a promising route to realize novel MIR applications. Here we demonstrate a hybrid nanostructure combining graphene and silicon carbide to extend the spectral phonon response of silicon carbide and enable absorption and field enhancement of the MIR photon via the excitation and hybridization of surface plasmon polaritons and surface phonon polaritons. We combine experimental methods and finite element simulations to demonstrate enhanced absorption of MIR photons and the broadening of the spectral resonance of graphene-coated silicon carbide nanowires. We also indicate subwavelength confinement of the MIR photons within a thin oxide layer a few nanometers thick, sandwiched between the graphene and silicon carbide. This intermediate shell layer is characteristically obtained using our graphitization approach and acts as a coupling medium between the core and outer shell of the nanowires.

An autofocus method to reduce acoustic inhomogeneity in microwave-induced thermo-acoustic tomography based on basis pursuit

In microwave-induced thermo-acoustic tomography, the quality of reconstructed images is seriously influenced by the speed of sound distribution, which is usually set according to the speed of sound (SoS) of the background coupling medium or an empirical value. To reduce defocusing and distortions induced by acoustic inhomogeneity in microwave-induced thermo-acoustic tomography, a method is proposed. We classify the initial reconstructed pressure by the difference in dielectrics and update the acoustic property accordingly. A spare spectrum is obtained by the proposed method and partitions the initial pressure into several clusters, and then SoS will be updated based on clinical statistics with which the pressure is reconstructed again. The proposed method is first validated in the anatomically realistic breast phantom; an ex vivo experiment based on a prototype system is carried out for further validation. The results prove that the proposed method has a reliable effect on reducing distortions than the state-of-art methods under the condition of a low signal to noise ratio.

Study on the energy transfer efficiency of explosive blasting with different coupling medium

Decoupled charge blasting can effectively reduce the peak pressure of hole wall and improve the blasting effect. Aiming at the issues associated with the explosive energy transferred into rock mass with different coupling medium, the deformation and failure characteristics of rock mass under explosion were analyzed theoretically with the consideration of strain rate effect of the rock mass, and the theoretical energy transfer efficiency of blasting with different coupling medium was obtained. Combined with the numerical simulations, the effects of rock mass properties, explosive categories and decoupled charge coefficient on the energy transfer efficiency of blasting with different coupling medium were studied. The results show that the energy transferred into rock mass from explosive of decoupling charge blasting is related to the coupling medium, the energy transfer efficiency of water coupling blasting is higher than that of air coupling blasting for the same charge structure and same blasting medium. When the charge structure and blasting rock mass are the same but the coupling medium is different, the energy transferred into the rock mass from explosive will be different, depending on blasting rock mass, explosive categories and decoupling charge coefficient. When blasting with the same decoupling charge coefficient but different coupling medium, the higher the rock mass strength, the greater the difference of energy transfer efficiency between different coupling medium. For blasting with the same rock mass properties and same charge structure, the difference of energy transfer efficiency between air coupling blasting and water coupling blasting increases with the increase of decoupling charge coefficient. For emulsion explosive exploding in siltstone, when the decoupling charge coefficient increases from 1.28 to 3.44, the energy transferred from water coupling blasting to surrounding rock mass increases from 1.45 to 6.52 times of air coupling blasting. The research results are of great reference significance for optimizing blasting design, improving explosion energy distribution and increasing the explosion energy utilization rate.

Microwave Tomography Using Random Multiple-Input–Multiple-Output Contrast Source Inversion

Microwave tomography using the contrast source inversion (CSI) method has been intensively researched especially in medical applications, where a coupling medium (CM) is usually used to improve imaging. Previous works noted that better results can be achieved when the CM is lossy. Nevertheless, lossy CM weakens the target response, especially when complicated scenario is imaged such as the head. In this letter, CSI is analyzed to indicate that the dielectric properties of CM are related to the condition number of a part of the objective function in each of CSI iteration. It is found that the value of this condition number is proportional to the ratio of maximum and minimum electric field intensity in the computational domain. Therefore, to reduce that ratio, a random multiple-input-multiple-output (RMIMO) scheme, which is implemented by applying a transformation matrix on the measured S-parameter matrix, is proposed to enable the use of loss-less CM and improves the imaging results. The proposed analysis and RMIMO-CSI method are validated using numerical head models.

Newly designed solid coupling medium for reducing trapped air pockets during extracorporeal shock wave lithotripsy_ a phantom study

IntroductionAir pockets between the lithotripter head and body surface are almost inevitably generated when applying a handful of gel onto the contact portion of the treatment head and that on the patient’s skin during coupling procedure. These air pockets can compromise the transmission of acoustic energy of shock wave and may significantly affect efficacy of stone disintegration. Comparing to conventional gel, this study aims to investigate efficacy of stone disintegration by using a proprietary isolation-coupling pad (“icPad”) as the coupling medium to reduce trapped air pockets during ESWL procedure.MethodIn this phantom study, Dornier lithotripter (Delta-2 RC, Dornier MedTech Europe GmbH Co., Germany) was used with a proprietary gel pads (icPad, Diameter = 150 mm, Thickness = 4 mm and 8 mm). The lithotripter was equipped with inline camera to observe the trapped air pockets between the contact surface of the lithotripter head. A testing and measuring device were used to observe experimental stone disintegration using icPad and semi-liquid gel. The conventional semi-liquid gel was used as control for result comparison.ResultsThe stone disintegration rate of icPad 4 mm and 8 mm after 200 shocks of energy at level 2 were significantly higher than that of the semi-liquid gel (disintegration rate 92.3%, 85.0% vs. 45.5%, respectively, p < 0.001). The number of shocks for complete stone disintegration by icPad of 4 mm and 8 mm at the same energy level 2 were significantly lower than that of the semi-liquid gel (the number of shocks 242.0 ± 13.8, 248.7 ± 6.3 vs. 351.0 ± 54.6, respectively, p = 0.011). Furthermore, quantitative comparison of observed air pockets under Optical Coupling Control (OCC) system showed that the area of air pockets in semi-liquid group was significantly larger than that of the group using icPad (8 mm) and that of the group using icPad (8 mm) after sliding (332.7 ± 91.2 vs. 50.3 ± 31.9, 120.3 ± 21.5, respectively, p < 0.05).ConclusionThe advantages of icPad includes: (1) reduced the numbers of shock wave and increased stone disintegration rate due to icPad’s superior efficacy; (2) significantly reduce trapped air pockets in ESWL coupling. Due to the study limitation, more data are needed to confirm our observations before human trials.

Damage detection of CFRP composites by electromagnetic wave nondestructive testing (EMW-NDT)

Damages such as fiber breakage and delamination are likely to occur inside CFRP composites when subjected to external forces, such as impact and fatigue load. These damages are mostly invisible and cause safety hazards during the service of the products. This study proposes a new type of nondestructive testing (NDT) method using electromagnetic wave (EMW) technique, EMW-NDT. It was proven that the proposed EMW-NDT method is effective in detecting damages such as delamination, crack or other defects in CFRP composites. The EMW-NDT method's detection capacity to the delamination size, delamination thickness, and slits in CFRP composites was investigated. A reasonable sensitivity to the damage volume change in delamination was confirmed with a damage area ratio of 12.6%/dB and a thickness change of 5.5 dB/mm. It was found that the incident angle of the EM wave plays a vital role in detecting sensitivity because of the skin effect in CFRP composites. The results confirmed that the proposed method demonstrates good detection sensitivity to delamination size and thickness. In terms of crack damage, the slit and its length were detected and the slit direction was successfully identified in this study based on the characteristics of the electromagnetic interference (EMI) shielding anisotropy in CFRPs. Moreover, the proposed EMW-NDT method with specified designed free-space measurement system is contactless, and no coupling medium is required; thus, it exhibits huge potential to be widely used as a new damage detection technique for CFRP composites.

THE BONE MICROSTRUCTURE IDENTIFICATION MODEL BASED ON BACKSCATTER MODE OF ULTRASOUND

Osteoporosis is defined by a decrease in bone mass and a deterioration in bone microstructure. It is a major public health issue and a significant economic burden for both individuals and society. Thus, monitoring bone mass and structure is necessary to prevent bone fragility and osteoporosis. This study aimed to develop a prototype of quantitative ultrasound (QUS) and to evaluate the feasibility of backscatter mode for the bone assessment. Ultrasound (US) signals that propagate through the bone can be characterized by comparing the signal from both transmitter and receiver transducers. The US backscattered signal depends on the characteristic of both medium and transducer. In this study, we analyzed the attenuated signal based on the parameters: type of bone (compact and spongy), type of coupling medium (air, starch, and gel), the angle between transducers and bone (30o, 60o, and 90o), and transducer distance (0, 10, 5, 15, 20 and 25 cm). We use only 1 MHz transducer frequency. The prototype has been evaluated by Digital Oscilloscope and LabVIEW user interface to observe received signals. The results of this study showed that there was a difference in amplitude of the US signal from compact and spongy bones. The amplitude is directly proportional to acoustic impedance and inversely proportional to the distance between transducers. There is a negative correlation between bone microstructure to attenuation, and compact bones have a greater attenuation coefficient than spongy bones.

Modeling and behavioral analysis of neurons under direction-dependent resistive, inductive and capacitive coupling

This study exploits the modeling and behavioral analysis of electrical coupling medium between neurons. A new electrical coupling model that represents two resistor, inductor and capacitor (RLC) circuits for a single link between two neurons is introduced by employing the biological evidences and electrical circuit theory knowledge. Herein, a model consisting of a network of multiple FitzHugh–Nagumo (FHN) neurons in a ring topology is also proposed. The presented model follows direction-dependent transmission based on resistive, inductive, and capacitive inter-neuronal electrical coupling medium for generalization purposes. The coupling medium, attributable to the direction-dependent information transmittance, admitting resistive, inductive and capacitive nature, reveals the astonished results such as the existence of two PID controllers for a single link among two neurons. Furthermore, the effects of difference in PID parameters by fixing the parametric difference and by increasing the parametric difference on synchronization are studied in order to explore the behavior of electrical coupling medium. Astoundingly, such behavioral analysis reveals that the coupling medium truly tracks the well-known proportional integral derivative (PID) characteristics curve.

Technical Note: Standalone application to generate custom reflectance Look-Up Table for advanced optical Monte Carlo simulation in GATE/Geant4.

The need for high-fidelity modeling of radiation detectors to perform reliable detector performance optimization using Monte Carlo simulations requires to accurately simulate the light transport in the scintillator and the light collection by the photodetector. In this work, we implement our well-validated crystal reflectance model computed from three-dimensional (3D) crystal surface measurement in a standalone open-source application to allow researchers to generate fully customized crystal reflectance look-up-tables (LUTs) to be used in optical Monte Carlo simulation. The LUTDavisModel application can be installed in a few minutes on Windows, macOS, and Linux, using 26MB of space. MATLAB Runtime is required and is automatically installed with the application. The core algorithm has been previously validated experimentally and implemented in GATE v8.0. The standalone is divided into five panels, each of which performing a specific task: generate LUTs from a combination of surface type, scintillator, and coupling medium available in the database (such as LSO or BGO) or custom; compute LUTs with the reflectors available and custom coupling thickness; create a mixture of coupling media to account for possible defects in the optical coupling; plot precomputed LUTs for visual comparison. Tooltips and errors/warnings facilitate the navigation. The reported computational times were obtained with an Intel Core i7 MacBook Pro. LUTs can be generated with computational time ranging from a few minutes to several hours depending on the selected surface, sampling, and computational power. A longer time is needed when using rough surfaces and thick coupling media (hundreds of ) due to increased photon tracking. We developed a user-friendly standalone application to generate LUTs that can be used inside GATE Monte Carlo simulations. It can be easily downloaded, installed, and used. Future optimizations will expand the database, decrease the computational time through greater parallelization, and include the generation of LUTs to study Cerenkov photons transport.

Regarding the acoustic coupling medium for the estimation of the depth of invasion in tongue squamous cell carcinoma on intraoral sonography with special reference to the interpretation of normal mucosal structure: A literature review

AbstractObjectiveThis study reviewed the literature addressing the use of a coupling medium to evaluate the extent of oral tongue squamous cell carcinoma (OTSCC) in intraoral sonography to assess the potentiality of this technique for the precise estimation of the depth of invasion (DOI).MethodsStudies for this paper were identified by a search of PubMed and manual searching of references from articles, using the search terms “lingual cancer” and “intraoral sonography” and their synonyms in the title and abstract fields. We excluded studies with no description of the coupling medium.ResultsFourteen studies were included in this study. Sterile or non‐sterile gel was used in 11 studies; however, no description about the surrounding normal mucosa was provided in these studies. In two studies, a dedicated acoustic coupling polymer gel was used, and the normal mucosal layer was demonstrated as a hypoechoic line underlying the mucosal surface in one study. Although the first report of the DOI measurement was performed with degassed water, no clear interpretation of the basement level of the surrounding mucosa was presented.ConclusionsInsufficient studies were available in the appropriate use of acoustic coupling medium from the viewpoint of the interpretation of the detailed normal anatomical structure of the tongue mucosa. Further studies are required to establish a standardized technique for the estimation of DOI in OTSCC.

Imaging the pediatric retina: An overview.

Recent decade has seen a shift in the causes of childhood blinding diseases from anterior segment to retinal disease in both developed and developing countries. The common retinal disorders are retinopathy of prematurity and vitreoretinal infections in neonates, congenital anomalies in infants, and vascular retinopathies including type 1 diabetes, tumors, and inherited retinal diseases in children (up to 12 years). Retinal imaging helps in diagnosis, management, follow up and prognostication in all these disorders. These imaging modalities include fundus photography, fluorescein angiography, ultrasonography, retinal vascular and structural studies, and electrodiagnosis. Over the decades there has been tremendous advances both in design (compact, multifunctional, tele-consult capable) and technology (wide- and ultra-wide field and noninvasive retinal angiography). These new advances have application in most of the pediatric retinal diseases though at most times the designs of new devices have remained confined to use in adults. Poor patient cooperation and insufficient attention span in children demand careful crafting of the devices. The newer attempts of hand-held retinal diagnostic devices are welcome additions in this direction. While much has been done, there is still much to do in the coming years. One of the compelling and immediate needs is the pediatric version of optical coherence tomography angiography. These needs and demands would increase many folds in future. A sound policy could be the simultaneous development of adult and pediatric version of all ophthalmic diagnostic devices, coupled with capacity building of trained medical personnel.

Metasurface-Enhanced Antennas for Microwave Brain Imaging.

Stroke is a very frequent disorder and one of the major leading causes of death and disability worldwide. Timely detection of stroke is essential in order to select and perform the correct treatment strategy. Thus, the use of an efficient imaging method for an early diagnosis of this syndrome could result in an increased survival’s rate. Nowadays, microwave imaging (MWI) for brain stroke detection and classification has attracted growing interest due to its non-invasive and non-ionising properties. In this paper, we present a feasibility study with the goal of enhancing MWI for stroke detection using metasurface (MTS) loaded antennas. In particular, three MTS-enhanced antennas integrated in different brain scanners are presented. For the first two antennas, which operate in a coupling medium, we show experimental measurements on an elliptical brain-mimicking gel phantom including cylindrical targets representing the bleeding in haemorrhagic stroke (h-stroke) and the not oxygenated tissue in ischaemic stroke (i-stroke). The reconstructed images and transmission and reflection parameter plots show that the MTS loadings improve the performance of our imaging prototype. Specifically, the signal transmitted across our head model is indeed increased by several dB‘s over the desired frequency range of 0.5–2.0 GHz, and an improvement in the quality of the reconstructed images is shown when the MTS is incorporated in the system. We also present a detailed simulation study on the performance of a new printed square monopole antenna (PSMA) operating in air, enhanced by a MTS superstrate loading. In particular, our previous developed brain scanner operating in an infinite lossy matching medium is compared to two tomographic systems operating in air: an 8-PSMA system and an 8-MTS-enhanced PSMA system. Our results show that our MTS superstrate enhances the antennas’ return loss by around 5 dB and increases the signal difference due to the presence of a blood-mimicking target up to 25 dB, which leads to more accurate reconstructions. In conclusion, MTS structures may be a significant hardware advancement towards the development of functional and ergonomic MWI scanners for stroke detection.