• MS-BE-00-01

Multiattribute Decision-Making: Use of Three Scoring Methods to Compare the Performance of Imaging Techniques for Breast Cancer Detection

Fred Azar

Multiple Attribute Decision Making (MADM) involves "making preference decisions (such as evaluation, prioritization, selection) over the available alternatives that are characterized by multiple, usually conflicting, attributes". The problems of MADM are diverse, and can be found in virtually any topic. In this paper, we use three different scoring methods for evaluating the performance of different imaging techniques used to detect cancers in the female breast. The need for such a decision support system arises from the fact that each of the several techniques which helps diagnose breast cancer today, has its own specific characteristics, advantages and drawbacks. These characteristics or attributes are generally conflicting. The goal is to detect as many malignant lesions in the breast as is possible, while identifying the maximum number of
benign lesions. The four imaging techniques that are compared here are Magnetic Resonance Imaging (MRI), Mammography, Ultrasonography, and Nuclear Medicine. The three different multiattribute scoring methods are the Simple Additive Weighting method (SAW), the Weighted Product Method (WPM), and the Technique for Order Preference by detail, and then used to rank the four imaging techniques. The results are analyzed and the validity and robustness of the methods are tested using post-evaluation analysis. 
 

• MS-BE-00-02

Fred Azar

Breast cancer is the most commonly diagnosed cancer and the second leading cause of cancer death among women in America. A few years ago the odds of developing breast cancer were reported as 1 in 13. Now the chance is 1 in 9. The only way today to find out for sure if a breast lump or abnormal tissue is cancer, is by having a biopsy: A suspicious tissue is removed by a surgical excision or needle biopsy and is examined under a microscope by a pathologist who makes the diagnosis. Imaging techniques of the breast are therefore vital since they will
allow early detection of cancer, and localization of the suspicious lesion in the breast for a biopsy procedure.

• MS-BE-00-03

Fred Azar
 

When doing high field (1.5T) magnetic resonance breast imaging, the use
of a compression plate during imaging after a contrast-agent injection may critically change the enhancement characteristics of the tumor, making the tracking of its boundaries very difficult. A new method for clinical breast biopsy is presented, based on a deformable finite element model of the breast. The geometry of the model is constructed from MR data, and its mechanical properties are based on a non-linear material model. This method allows
imaging the breast without compression before the procedure, then
compressing the breast and using the finite element model to predict the tumor's position. The axial breast contours and the segmented slices are ported to a custom-written MR-image contour analysis program, which generates a finite element model (FEM) input file readable by a commercial FEM software. A deformable silicone gel phantom was built to study the movement of an inclusion inside a deformable environment. The hyperelastic properties of the
phantom materials were evaluated on an Instron Model 1331 mechanical
testing machine. The phantom was placed in a custom-built pressure
device, where a pressure plate caused a 14% (9.8mm) compression. The
phantom was imaged in a 1.5T magnet (axial and coronal), in the undeformed and deformed states. An FEM of the phantom was built using the custom-written software from the MR data, and another FEM of the
phantom was built using a commercial pre-processor from the phantom's
directly measured dimensions. The displacements of the inclusion center
and its boundaries were calculated, both from the experimental and FEM
results. The calculated displacements from both models are within 0.5mm
of each other, and agree within 1.0mm with the experimental results. This difference is within the imaging error.

MS-BE-00-04

Effects of Demyelination on the Time Constants and Amplitude of the Action Potential Due to Multiple Sclerosis

The anatomy of the myelinated and demyelinated nerve fiber in the pathology of Multiple Sclerosis is recalled. A computer simulation is devised using MATLAB and is used to evaluate the effects of a demyelinated internode on the amplitude and time constants of a traveling action potential, in a voltage clamp experiment. The action potential is modeled as a combination of two exponentials with different time constants. RC circuit and cable theory are used to model the node-internode complex. A few relevant patterns of internodal demyelination are investigated as well as their effects on action potential amplitude and time constants.

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