Computational Biomagnetics




Our group at the University of Washington is involved in computer modeling of the electrical activity of the human heart and brain under normal and diseased conditions and developing their noninvasive medical diagnostic applications. We are also developing biomedical applications of the electromagnetic fields. Currently we are working on the following projects:
 
 
 

From the magnetic resonance imaging data anatomically accurate 3-D computer models of the human head and torso are built for computer modeling of the electrical activity of the human heart and brain. Studies are being conducted on developing efficient adaptive finite element models to quickly solve the voltage and current distribution in the whole and torso on desk-top workstations. This requires developing efficient and automatic image segmentation techniques, finite element modeling techniques and techniques for solving large matrices.
  The human body is electrically very active. Examples include the electrical activity of human heart (ECG), brain (EEG), nerve fibers and muscles. Associated with these electrical activities are biomagnetic fields called magnetocardiograms (MCGs) and magnetoencephalograms (MEGs) which are very weak but can be measured with very sensitive SQUID biomagnetometers. Heart magnetic field is about 10-20 pico-teslas and the brain magnetic field is about 50-100 femto-teslas. From the measured electric or magnetic field quantities one can localize the sites of the activation in the heart or brain for noninvasive medical diagnostics. Our group is developing these newer imaging techniques to reconstruct current distributions in the heart or brain. Modeling is performed for heart under normal and diseased conditions to see how the torso potentials and magnetic fields change under normal and diseased conditions. Eventually this will be used for noninvasive detection of heart diseases. Similarly for the brain the electrical activity is modeled with very accurate anatomical models of the head. Through modeling procedures we predict how the scalp potentials and magnetic fields vary under normal and diseased conditions. Most of the work is focused on visual, auditory, and motor evoked response studies related to various types of brain disorders.
  From the measured electric or magnetic field data one needs to reconstruct the current distribution in the heart wall or localize the sites of the electrical activity in the brain. This requires solving the under-determined inverse problem by use of numerical optimization techniques, artificial neural networks and a combination of signal and image processing techniques. Currently we are developing techniques to solve the bioelectric and biomagnetic inverse problem in an integrated fashion to better localize the sites of the electrical activity in the brain with a mm size resolution.
  One imaging modality alone does not provide a complete picture of what is happening inside the brain. Magnetic resonance imaging (MRI) provides a detailed view of anatomy of the head and brain. The hemodynamic and metabolic activity of the brain is imaged with functional magnetic resonance imaging (fMRI) and magnetic resonance spectroscopy (MRS), respectively. The electrical current distribution is reconstructed from the measured EEG/MEG data sets. Research is being conducted by our group on the fusion and 3-D display of the multi-modality imaging data.
  We are developing Matlab based tools for 3-D visualization of the anatomical models of the human head and torso. These models are superimposed with the electric and magnetic fields, and the current distribution. Techniques are also being developed to peel-away the anatomical layers and look inside the models of the head and torso in an interactive graphical fashion. Qualification of the volumes and surfaces of different parts and tissue types is also being performed.
 

6, Medical Applications
 

The above tools are being developed for medical diagnostic applications. Currently our focus is on applications to epilepsy and stroke for the brain, and electrical arrhythmia modeling for the heart. Other applications such as, noninvasive detection of Alzheimer, learning disabilities, autism etc will also be explored in the future.
 

7. Magnetic field Treatment of malaria and Cancer
 

We have developed techniques for destruction of malaria parasite by use of pulsed magnetic fields. It provides a novel method to kill malaria parasite without or in combination with malaria drugs. Magnetic field treatment of malaria is an alternative for drug resistant malaria which is spreading at an alarming rate in Asia and Africa. We are performing similar experiments on treatment of cancer with pulsed magnetic fields. Our work consists of development and design of exposure systems, computation of field exposer parameters, and taking part in clinical experiments. This work is being carried out jointly with Seattle Biomedical Research Institute.
 

8. Modeling of the Magnetic Susceptibility Artifacts in MRI Machines
 

The magnetic susceptibility of the human tissue causes a slight distortion of the fields in the magnetic resonance imaging (MRI) machines. These often distort the MRI images. We are involved in computer modeling of these field distortions and in developing techniques to correct these susceptibility dependent imaging artifacts.
 
 

Student Projects




Student projects are available at various levels. Short term projects of one or two quarter long are available for B.S. and M,S. degrees. More detailed projects are available for MS and PhD thesis work. Each project requires a slightly different background. However, in general, some background in electromagnetic field computations, signal and image processing, numerical techniques and optimization, computer visualizations is needed to carry out these projects. Interested students should contact the following people in EE:
 

Ceon Ramon, ceon@u.washington.edu

Robert J. Marks, marks@ee.washington.edu

Akira Ishimaru, Ishimaru@ee.washington.edu
 
 

Collaborators




The above projects are highly interdisciplinary and require collaboration between scientists, engineers and medical professional. Currently following people are collaborating on these projects (in alphabetical order):
 

Jean Feagin, Pathology

Mark Holms, Neurology, EEG measurements, Epilepsy

Akira Ishimaru, Electrical Engineering, Electromagnetic Fields

Sermsak Jaruvatadilok, Electrical Engineering, Electromagnetic Fields

Yasuo Kuga, Electrical Engineering, Field Measurements

Henry Lai, Bioengineering, Biological Field Effects

Ken Maravilla, Radiology, Magnetic Resonance Imaging

Robert J. Marks, Electrical Engineering, Signal Processing, Neural Networks

John Miller, Neurological Surgery, Epilepsy

Linda Ojeman, Neurological Surgery, Epilepsy

Jean Poole, Cardiology, Arrhythmia

Ceon Ramon, Electrical Engineering, Finite Element Modeling, Image Processing, Visualization

Todd Richards, Radiology, Magnetic Resonance Imaging

Phil Schwartzkroin, Neurological Surgery, Pediatric Epilepsy