Stretching the Limits of MRI-Stretchable and Modular Coil Array Using Conductive Thread Technology.

Objective: We propose a modular stretchable coil design using conductive threads and commercially available embroidery machines. The coil design increases customizability of coil arrays for individual patients and each body part.

Methods: Eight rectangular coils were constructed with custom-fabricated stretchable tinsel copper threads incorporated onto textile.

Patellar tendon biomechanical and morphologic properties and their relationship to serum clinical variables in persons with prediabetes and type 2 diabetes.

Tendon biomechanical properties and fibril organization are altered in patients with diabetes compared to healthy individuals, yet few biomarkers have been associated with in vivo tendon properties. We investigated the relationships between in vivo imaging-based tendon properties, serum variables, and patient characteristics across healthy controls (n = 14, age: 45 ± 5 years, body mass index [BMI]: 24 ± 1, hemoglobin A1c [HbA1c]: 5.3 ± 0.

Parametric Design of a 3D-Printed Removable Common-Mode Trap for Magnetic Resonance Imaging.

Radiofrequency coils are utilized during transmit and receive of MRI signals. Cable traps remove common-mode current from the coaxial cable shield, which helps improve the image quality and reduces risks of burns to the patient. Traditional cable traps use wounded coaxial cables that limit the flexibility in the design process.

Stretchable receive coil for 7T small animal MRI.

Receive coils used in small animal MRI are rigid, inflexible surface loops that do not conform to the anatomy being imaged. The recent trend toward design of stretchable coils that are tailored to fit any anatomical curvature has been focused on human imaging. This work demonstrates the application of stretchable coils for small animal imaging at 7T.

Mechanistic Computational Modeling of Implantable, Bioresorbable Drug Release Systems.

Implantable, bioresorbable drug delivery systems offer an alternative to current drug administration techniques; allowing for patient-tailored drug dosage, while also increasing patient compliance. Mechanistic mathematical modeling allows for the acceleration of the design of the release systems, and for prediction of physical anomalies that are not intuitive and may otherwise elude discovery. This study investigates short-term drug release as a function of water-mediated polymer phase inversion into a solid depot within hours to days, as well as long-term hydrolysis-mediated degradation and erosion of the implant over the next few weeks.

Development of brain atlases for early-to-middle adolescent collision-sport athletes.

Human brains develop across the life span and largely vary in morphology. Adolescent collision-sport athletes undergo repetitive head impacts over years of practices and competitions, and therefore may exhibit a neuroanatomical trajectory different from healthy adolescents in general. However, an unbiased brain atlas targeting these individuals does not exist.

3D Cell Culture for the Study of Microenvironment-Mediated Mechanostimuli to the Cell Nucleus: An Important Step for Cancer Research.

The discovery that the stiffness of the tumor microenvironment (TME) changes during cancer progression motivated the development of cell culture involving extracellular mechanostimuli, with the intent of identifying mechanotransduction mechanisms that influence cell phenotypes. Collagen I is a main extracellular matrix (ECM) component used to study mechanotransduction in three-dimensional (3D) cell culture. There are also models with interstitial fluid stress that have been mostly focusing on the migration of invasive cells.

Electromagnetic simulation of a 16-channel head transceiver at 7 T using circuit-spatial optimization.

Purpose: With increased interest in parallel transmission in ultrahigh-field MRI, methods are needed to correctly calculate the S-parameters and complex field maps of the parallel transmission coil. We present S-parameters paired with spatial field optimization to fully simulate a double-row 16-element transceiver array for brain MRI at 7 T.

Methods: We implemented a closed-form equation of the coil S-parameters and overall spatial field.

Global and peak local specific absorption rate control on parallel transmit systems using k-means SAR compression model.

Purpose: To improve the specific absorption rate (SAR) compression model capability in parallel transmission (pTx) MRI systems.

Methods: A k-means clustering method is proposed to group voxels with similar SAR behaviors in the scanned object, providing a controlled upper-bounded estimation of peak local SARs. This k-means compression model and the conventional virtual observation point (VOP) model were tested in a pTx MRI framework.

Characterizing near-infrared spectroscopy signal under hypercapnia.

Vasoactive stress tests (i.e. hypercapnia, elevated partial pressure of arterial CO [PaCO ]) are commonly used in functional MRI (fMRI), to induce cerebral blood flow changes and expose hidden perfusion deficits in the brain.

Current and Emerging Magnetic Resonance-Based Techniques for Breast Cancer.

Breast cancer is the most commonly diagnosed cancer among women worldwide, and early detection remains a principal factor for improved patient outcomes and reduced mortality. Clinically, magnetic resonance imaging (MRI) techniques are routinely used in determining benign and malignant tumor phenotypes and for monitoring treatment outcomes. Static MRI techniques enable superior structural contrast between adipose and fibroglandular tissues, while dynamic MRI techniques can elucidate functional characteristics of malignant tumors.

Modelling and B1 Shim Analysis of 16-Element Transceiver Array at 7 T.

The work examines the workflow of using commercially available software for electromagnetic modelling and validation of a transceiver array coil operating at 298 MHz for magnetic resonance imaging and spectroscopy at 7 T. The coneshaped, tight-fit parallel transmit head array consists of two rows with eight loop coils per row and transmits two distinct spatial distributions by means of shimming. Considerations for finite-difference time-domain simulation setup and post-processing with circuit-domain co-simulation are examined, as is the generation of virtual observation points suitable for online safety monitoring.

Dual-Tuned Removable Common-Mode Current Trap for Magnetic Resonance Imaging and Spectroscopy.

Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) are preferred methods of gathering structural and metabolic information from the body due to their non-invasive approach to obtaining a diagnosis. Dual-tuned radiofrequency (RF) coils can detect signals produced by both hydrogen and a second atomic nuclei of interest. However, undesired electromagnetic coupling often confounds both the design and utilization of RF coils.

Stitching Stretchable Radiofrequency Coils for MRI: A Conductive Thread and Athletic Fabric Approach.

Objective: We propose a novel flexible and entirely stretchable radiofrequency coil for magnetic resonance imaging. This coil design aims at increasing patient comfort during joint imaging while maintaining or improving image quality.

Methods: Conductive silver-coated thread was stitched in a zigzag pattern onto stretchable athletic fabric to create a single-loop receive coil.

Multiple-Input Multiple-Output (MIMO) MRI: Combining Parallel Excitation and Parallel Reception for Enhanced Imaging.

Magnetic resonance imaging (MRI) plays a critical role in visualizing the structure and functions of the human body. In order to accelerate imaging time and improve image quality, radio-frequency (RF) coil receive arrays are commonly employed to acquire the magnetic resonance (MR) signal. Similarly, multiple transmit coils have been shown to accelerate and refine RF excitation.

Conductive Thread-Based Stretchable and Flexible Radiofrequency Coils for Magnetic Resonance Imaging.

Objective: We propose a novel flexible and entirely stretchable radiofrequency coil for magnetic resonance imaging. This coil design aims at increasing patient comfort during imaging while maintaining or improving image quality.

Methods: Conductive silver-coated thread was zigzag stitched onto stretchable athletic fabric to create a single-loop receive coil.

Toward 7T breast MRI clinical study: safety assessment using simulation of heterogeneous breast models in RF exposure.

Purpose: To facilitate assessment of RF power deposition and temperature rise within the breast, we present a method to seamlessly join heterogeneous breast models with standard whole-body models and demonstrate simulations at 7 T.

Methods: Finite-difference time-domain electromagnetic and bioheat simulations are performed to analyze the specific absorption rate (SAR) and temperature rise distributions in 36 Breast Imaging Reporting and Data System (BI-RADS) categorized breast models fused to 2 female whole-body models while transmitting from a 7T breast volume coil. The breast models are uncompressed in the prone position and feature heterogeneous tissue contents; fusion with human models uses affine transformation and the level-set method.

Dependence on subconcussive impacts of brain metabolism in collision sport athletes: an MR spectroscopic study.

Long term neurological impairments due to repetitive head trauma are a growing concern for collision sport athletes. American Football has the highest rate of reported concussions among male high school athletes, a position held by soccer for female high school athletes. Recent research has shown that subconcussive events experienced by collision sport athletes can be a further significant source of accrued damage.

Automated modification and fusion of voxel models to construct body phantoms with heterogeneous breast tissue: Application to MRI simulations.

Background: Human voxel models incorporating detailed anatomical features are vital tools for the computational evaluation of electromagnetic (EM) fields within the body. Besides whole-body human voxel models, phantoms representing smaller heterogeneous anatomical features are often employed; for example, localized breast voxel models incorporating fatty and fibroglandular tissues have been developed for a variety of EM applications including mammography simulation and dosimetry, magnetic resonance imaging (MRI), and ultra-wideband microwave imaging. However, considering wavelength effects, electromagnetic modeling of the breast at sub-microwave frequencies necessitates detailed breast phantoms in conjunction with whole-body voxel models.

Trap Design and Construction for High-Power Multinuclear Magnetic Resonance Experiments.

Performing multinuclear experiments requires one or more radiofrequency (RF) coils operating at both the proton and second-nucleus frequencies; however, inductive coupling between coils must be mitigated to retain proton sensitivity and coil tuning stability. The inclusion of trap circuits simplifies placement of multinuclear RF coils while maintaining inter-element isolation. Of the commonly investigated non-proton nuclei, perhaps the most technically demanding is carbon-13, particularly when applying a proton decoupling scheme to improve the resulting spectra.

Effects of coplanar shielding for high field MRI.

This work investigates the efficacy of "coplanar shielding," in which copper shields are oriented concentric and coplanar to the RF coils rather than implemented as a full ground plane behind them. Following FDTD simulations to determine optimal shielding parameters, two coil geometries were constructed: a circular loop surface coil and a half-volume five-element receive array. Each was evaluated using bench measurements with and without coplanar shielding.

A Switched-Mode Breast Coil for 7 T MRI Using Forced-Current Excitation.

In high-field magnetic resonance imaging, the radio frequency wavelength within the human body is comparable to anatomical dimensions, resulting in B1 inhomogeneity and nonuniform sensitivity patterns. Thus, this relatively short wavelength presents engineering challenges for RF coil design. In this study, a bilateral breast coil for (1)H imaging at 7 T was designed and constructed using forced-current excitation.