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Brain activities to major and minor chords and to major and minor cadence sequences were measured by sparse scanning fMRI. Areas activated by major and minor chords and cadence sequences were examined. Some of them are known to be related to emotion, motivation, arousal or reward. In general, minor chords activated larger areas of brain regions than major chords. Some activated areas have not been...
Accurate estimation of the human head conductivity is important for the diagnosis and therapy of brain diseases. Induced Current - Magnetic Resonance Electrical Impedance Tomography (IC-MREIT) is a recently developed non-invasive technique for conductivity estimation. This paper presents a formulation where a low number of material parameters need to be estimated, starting from MR eddy-current field...
Here we demonstrate the mechanical robustness of microfabricated torsional magnetic actuators in withstanding the magnetic fields produced by a 7 T MRI magnet. The static and dynamic mechanical characteristics of 30 devices were quantitatively measured before and after exposure to both uniform and non-uniform magnetic fields. The results show no statistically significant change in both the static...
The chemotherapy magnetically controlled under Magnetic Resonance Imaging (MRI) is currently one of the active areas of cancer research. This paper proposes a precise model of a therapeutic microrobot magnetically steered in blood vessels. This modeling approach takes into account the non-Newtonian behavior of blood, as well as wall effect on the blood's profile and robot-to-wall interaction forces...
Multimodality image registration is a critical issue in image-guided cancer ablation techniques. Focal therapies of prostate cancer are usually monitored using ultrasound imaging, while the dose planning is performed on MRI. In this study, a new multimodality images registration and deformation method, based on the Thin Plate Splines -Rigid Point Matching (TPS-RPM) algorithm, is introduced. The Method...
This paper describes and assesses for the first time the use of a handheld 3D laser scanner for scalp EEG sensor localization and co-registration with magnetic resonance images. Study on five subjects showed that the scanner had an equivalent accuracy, a better repeatability, and was faster than the reference electromagnetic digitizer. According to electrical source imaging, somatosensory evoked potentials...
Imaging of cardiac morphology and functions in high spatiotemporal resolution using MRI is a challenging problem due to limited imaging speed and the inherent tradeoff between spatial resolution, temporal resolution, and signal-to-noise ratio (SNR). The partially separable function (PSF) model has been shown to achieve high spatiotemporal resolution but can lead to noisy reconstructions. This paper...
A catheter is successfully bent and steered by applying magnetic gradients inside a Magnetic Resonance Imaging system (MRI). One to three soft ferromagnetic spheres are attached at the distal tip of the catheter with different spacing between the spheres. Depending on the interactions between the spheres, progressive or discontinuous/jumping displacement was observed for increasing magnetic load....
MRI provides a safe, high-resolution imaging modality that can be used to assist physicians during intra-operative and post-operative phases of prostate brachytherapy. The metallic outer structure of brachytherapy seeds, however, naturally produces dark features in MR imagery, which can be confused with other image voids. This work explores the application of resonant frequency offset maps to predict...
This paper describes the synthesis of thermoresponsive hydrogel bead for the implementation of untethered medical microrobots and other microdevices. These entities will have magnetic nanoparticles embedded, and will be targeted inside the body with an adapted Magnetic Resonance Imaging (MRI) system, and then triggered by the application of an alternating magnetic field for various functions, including...
In this paper, we present an analysis of magnetoencephalography (MEG) signals from a patient with whole-body chronic pain in order to investigate changes in neural activity induced by DBS. The patient is one of the few cases treated using DBS of the anterior cingulate cortex (ACC). Using MEG to reconstruct the neural activity of interest is challenging because of interference to the signal from the...
A new propulsion method for sub-millimeter implants is presented that achieves high power to thrust conversion efficiency with a simple implementation. Previous research has shown that electromagnetic forces are a promising micro-scale propulsion mechanism; however the actual implementation is challenging due to the inherent symmetry of these forces. The presented technique translates torque into...
Classic geometric active contour algorithms have the limitation of segmenting the image into only two regions: background and object of interest. A new multiphase level set algorithm for the segmentation of two or more regions of interest is proposed. This algorithm avoids by construction the presence of overlapped and void regions and no additional coupling terms are required. In addition, the number...
Stanford type B aortic dissections (TB-AD), which split the descending aorta in a true and false lumen, have better in-hospital survival than type A dissections affecting the ascending aorta. However, short-term and long-term prognosis for the individual patient remains challenging, with one in four patients not surviving after 3 years. Towards a better understanding of the influence of tear location...
Brain volume segmentation from neonatal magnetic resonance images (MRI) offers the possibility of exploring the developmental changes, measuring the brain growth, detecting early disorders and three-dimensional (3D) volume reconstruction. However, such segmentation is challenging mainly due to the fast growth process, complex anatomy of the developing brain and often poor MRI quality. Existing techniques...
This paper presents a three dimensional finite-difference time-domain (FDTD) scheme in cylindrical coordinates with an improved algorithm for accommodating the numerical singularity associated with the polar axis. The regularization of this singularity problem is entirely based on Ampere's law. The proposed algorithm has been detailed and verified against a problem with a known solution obtained from...
Automated image detection of white matter changes of the brain is essentially helpful in providing a quantitative measure for studying the association of white matter lesions with other types of biomedical data. Such study allows the possibility of several medical hypothesis validations which lead to therapeutic treatment and prevention. This paper presents a new clustering-based segmentation approach...
This paper presents a new method for performing supervised learning (classification) and demonstrates the technique by applying it to the detection of breast cancer from the dynamic information obtained in magnetic resonance imaging examinations. The proposed method is a vector machine similar to the established support vector machine (SVM) method, however, our method involves a reformulation of the...
The geometry of conduits derived from in vivo image data is subject to acquisition and reconstruction errors. This results in a degree of uncertainty in defining the bounding geometry for a patient-specific anatomical conduit. The impact of the conduit geometry uncertainty should be considered with respect to haemodynamic clinically relevant measures that may alter the perception and evaluation of...
Objective and early detection of Alzheimer's disease (AD) is a demanding problem requiring consideration of manymodal observations. Potentially, many features could be used to discern between people without AD and those at different stages of the disease. Such features include results from cognitive and memory tests, imaging (MRI, PET) results, cerebral spine fluid data, blood markers etc. However,...
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