Project7 Final Paper

ECE 345 SENIOR DESIGN LABORATORY


MRI CARDIAC VOLUME ANALYZER



by



Rajesh Shah, Matthew Sztelle





TA: Ben Floering

Spring 1999

Project 7

















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ABSTRACT

Magnetic Resonance Imaging (MRI) is a non-intrusive method used to obtain two-dimensional images of the body. Presently its functionality is limited to static organs andtissues. As a result, it is not possible to image organs such as the heart and lungs.
In an effort to increase the functionality of the MRI as well as other imaging machines, we have studied and built a circuit that reads the heart wave and passes a signal at a specified time during the cycle. This would then allow for imaging a nearly constant volume in the heart, thereby avoiding the previousproblem of a continuously changing heart volume.





























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TABLE OF CONTENTS
PAGE

1. INTRODUCTION (RS) ……………………………………………… 1
1. Function .………………………………………………………… 1
2. Diagram .………………………………………………………… 1
3. Original Performance Specifications…………………………….. 2
4. Final Performance Specifications ………………………………...2
5. Design Stages ……………………………………………………. 3
1. ECG Amplifier Design …………………………………… 3
2. Differentiator Design ……………………………………... 3
3. Driven Right Leg Circuit …………………………………. 3
4. Comparator and Inverter with Diode Design ……………... 3
2. ECG AMPLIFIER DESIGN (RS) ……………………………………. 4
1. Design Approach ………………………………………………… 4
2. Circuit Design……………………………………………………. 4
3. Final Circuit ……………………………………………………… 6
3. DIFFERENTIATOR DESIGN (RS) …………………………………. 8
1. Design Approach ………………………………………………… 8
2. Circuit Design ..………………………………………………….. 9
3. Final Circuit ……………………………………………………… 9
4. DRIVEN RIGHT LEG CIRCUIT (RS) …….…………………..……. 10
1. Design Approach ………………………………………………… 10
2. Circuit Design ……………………………………………………. 10
3. Final Circuit ……………………………………………………… 115. COMPARATOR, INVERTER, AND DIODE (RS) …………………. 12
1. Design Approach ………………………………………………… 12
2. Circuit Design ……………………………………………………. 12
3. Final Circuit ……………………………………………………… 13
6. MEASUREMENT AND TESTING (MS) …………………………… 14
1. Verification Using the FOGG M310 ECG Simulator …………… 14
2. Verification Using Live Test Subjects …………………………… 17
7. COST ANALYSIS (MS)……………………………………………… 19
1. Parts ………………………………………………………………. 19
2. Labor ……………………………………………………………… 19
3. Total Cost Incurred ……………………………………………….. 19
8. CONCLUSION (MS) …………………………………………………. 20

APPENDIX A. THE CARDIAC ELECTRIC SIGNAL AND
VOLUME (RS) ……………………………………. 21
APPENDIX B. REFERENCES (RS) ………………………………. 23


APPENDIX C. TOLERANCE ANALYSIS (MS) ............................. 24


1. INTRODUCTIONCurrently, Magnetic Resonance Imaging (MRI) machines are used mostly to image static anatomical features. This is due to the series of imaging “steps” a MRI machine needs to take before compiling a final image. The MRI machine must encode a two-dimensional slice of a body via phase steps. Data from each of these steps must then be acquired independent of every other step. Since the MRI machine needsa finite amount of time per step, the time to acquire the total image is the sum of the time needed to acquire data from each individual phase step. As a result, biological organs that change volume over time produce blurred images since each phase encoding step may be taken at varying volumes of the organ.
One such organ is the heart. The heart is constantly beating and cannot be stopped. Theheart uses electrochemical gradients to control the heartbeat. The electrochemical gradients can be transformed to electrical impulses that can be analyzed by electronic circuitry. This suggests the possibility of being able to image at a specified time in the cardiac cycle.
The purpose of this project is to design, build, and...