We proposed an indentation-vibration-based method to simultaneously measure the cellular mechanical properties in situ, including cellular mass, elasticity and viscosity, based on the principle of forced vibration stimulated by simple harmonic force using an atomic force microscope system integrated with a piezoelectric transducer as the substrate vibrator.
In this study, we propose a structured-learning-based segmentation framework to extract the perivascular spaces (PVSs) from high-resolution 7T MR images. Specifically, we integrate three types of vascular filter responses into a structured random forest for classifying each voxel into two categories.
We develop a simple physiologically based mechanistic model of CO2 exhalation that closely accounts for the capnogram shape in normal subjects and in patients with obstructive lung disease. The model parameters – alveolar CO2 concentration, dead-space fraction, and exhalation time constant – are chosen to obtain a patient-specific fit to the recorded capnogram.
Electrical Impedance Tomography (EIT) uses direct contact electrical stimulation and measurement at the body surface to image the electrical properties of internal tissues. EIT is useful when anatomical or physiological phenomena create contrasts in the tissue electrical properties, either through changes in the conductivity of tissue or the movement of conductively contrasting fluids or gasses.
This MR-based conductivity imaging (MRCI) toolbox is available to download. It includes Matlab functions for image reconstructions in magnetic resonance electrical impedance tomography (MREIT), diffusion tensor MREIT (DTMREIT), conductivity tensor imaging (CTI), and magnetic resonance current density imaging (MRCDI).
We review the basic principle of electrical properties tomography (EPT), reconstruction methods, biomedical applications including tumor imaging, and existing challenges. As an important application of EPT, the estimation of specific absorption rate (SAR) and its current development will also be discussed.
This review paper focuses on algorithmic aspects of quantitative susceptibility mapping (QSM) that solves the magnetic field-to-magnetization inverse problem under conditions of noisy and incomplete field data acquired using MRI. The forward problem is presented as a partial differential equation, whose fundamental solution characterizes noise and model errors as streaking and shadow artifacts in susceptibility map reconstruction.
We developed a robust strategy to image and characterize gastric emptying and motility in rats based on contrast-enhanced MRI and computer-assisted image processing. Results demonstrate an optimized MRI-based strategy to assess gastric emptying and motility in rats, paving the way for using this technique to understand GI diseases, or test new therapeutics in rat models.
We aim to probe the neuromechanics underpinning human locomotion. This information can be used to improve our understanding of typical and atypical joint behaviors, and to improve the design and control of gait assistive devices.
A new subspace approach to spectral quantification for MR spectroscopic imaging (MRSI) is reported. It represents the spectral distribution of each molecule using a low-dimensional subspace and the entire spectrum as a union-of-subspaces.