Gastroscope
Advisor:
Dr. Ata Akin
Design Team:
Casey Gavinski
Kenneth Hoyt
Ashish Patel
Kalpesh Trivedi
Problem Background
 Diabetes Mellitus
 Gastroparesis
 Techniques for Diagnosis
Invasive
Non-invasive
Methods of Diagnosis
 Nuclear Medicine Test
 Patient consumes small amount of radioactive material
 Scanner monitors amount of radioactivity in stomach
 Upper Gastrointestinal (GI) Endoscopy Test
 Camera inserted into digestive tract
 Visually examines stomach
 Intraluminal Manometry
Invasive
 Baloon inserted into stomach
 Measures pressure generated by stomach contractions
 Electrogastrography (EGG)
Electrogastrography
 Measurement of Gastric Myoelectrical
Potential Signals
Electrodes placed on abdominal surface
Testing performed during states of
Fasting and Postprandial
Correlation between EGG signals
and gastric motility
Non-Invasive !!
EGG Signal
Internal EGG Measurement
0.4
Amplitude (mV)
0.3
0.2
0.1
0
-0.1
-0.2
0
20
40
60
Time (sec)
80
100
120
80
100
120
Surface EGG Measurement
0.4
Amplitude (mV)
0.3
0.2
0.1
0
-0.1
-0.2
0
20
40
60
Time (sec)
 Gastric Myoelectrical Signals (500μV)
EGG Signal
9
8
Magnitude
7
6
5
4
3
2
1
0
0
50
100
Frequency (cpm)
 Primary Frequency Component
3 cpm (0.05 Hz)
150
Existing EGG Systems
 Signal Measurement Bandwidth
1-18 cpm (0.02-0.3 Hz)
Primary Frequency
 Stand Alone
Mobility Limited
 Portable
No Graphical Display
Not Stand Alone
Gastroscope




Portable
Stand Alone System
Graphical Display
Increased Bandwidth
EGG Signal
9
8
Magnitude
7
6
5
4
3
2
1
0
0
50
100
150
Frequency (cpm)
 Secondary Frequency Component
50 – 80 cpm (0.8 – 1.3 Hz)
Why the 50 to 80 cpm ?
 3cpm range requires monitoring throughout fasting and
postprandial states. (Differential Comparisons)
 50 to 80 cpm range provides consistent results with a short
time reading.
 50 to 80 cpm range closely correlated to Intraluminal
Manometry Test in dogs. (Diagnostic Charts Available)
 Create look-up charts for faster more accurate
diagnosis.
Gastroscope System Architecture
Function
Generator
Amplifier
Spreadsheet
(Excel)
Laptop
(LabVIEW)
Fiter
DAQ
Analog Signal Processing
 DC Amplifier
Instrumentation Amplifier
Gain > 10,000
Low Noise
 Filter
Low Pass
Flat Response
Sharp Roll-off
Amplifier Schematic
V+
V+
C
C
V+
V+
R
INPUT
+
INA121
Rc
_
+
INA121
Rc
_
R
+
+
OPA2131A
OPA2131A
_
OUTPUT
R
C
V-
V-
50 k
 100
Rc
Rc  510 
Gain  1 
_
R
C
V-
V-
fc 
1
2RC
fc  20 Hz
V   15V
C  1F
V   15V
R  8.2 k
OUTPUT
Printed Circuit Board (PCB)
Amplifier Response
 Amplifier and filter response to an input of 100 μv at 1 Hz
Amplifier Response (Cont’d)
 Amplifier and filter response to an input of 100 μv at 15 Hz
Amplifier Response (Cont’d)
 Amplifier and filter response to an input of 1 mv at 1 Hz
Amplifier Response (Cont’d)
 Amplifier and filter response to an input of 1 mv at 15 Hz
DSP Flow Chart
EGG Signal
Data Windowing
Hanning Windowing
Mean Subtraction
Fast Fourier
Transform
Primary Signal
3 cpm
(0.05 Hz)
Window Averaging
Peak Detection
and
Corresponding
Frequency
Secondary Signal
50 - 80 cpm
(0.83 - 1.33 Hz)
Power
Display and Memory
Matlab Simulation
15
Fasting State
Postprandial State
Magnitude
10
5
0
10
20
30
40
50
60
70
Frequency (cpm)
80
90
100
110
120
Matlab Simulation (Cont’d)
3
Fasting State
Postprandial State
2.5
Magnitude
2
1.5
1
0.5
0
0
50
100
Frequency (cpm)
150
Alternative System Design
 Laptop Based Design
 Near Real Time Data Analysis
 LabVIEW Software
 Data Storage in Spreadsheet Format
 GUI Interface
 Portable
 Research Applications
• IRB Approved
Future Work




Integrated System
DSP Based Architecture
Properly Configured ADC
Touchscreen Display (LCD)
Senior Design Expenditures
Component
Printed Circuit Board (PCB)
Integrated Circuits
Shielded Electrode Lead Assembly
Large Electrodes (50)
DSP Workshop/Starter Kits
Misc. Hardware
Labtop Computer
LabVIEW Software
DAQ Card-AI-16E-4
Total Cost
Cost
$20
NA
$125
$35
$700
$40
NA
NA
NA
$920
4 Year Financial Estimation
Role
Engineer
Subtotal
Overhead and Benefits @ 100%
Product Manufacturing ($600/unit)
Supplies
Equipment
Travel
Total Cost for Production
Unit Price
Appoint
4
Effort
100%
Year 1
Year 2
Year 3
Year4
$30,000
$31,500
$33,075
$34,729
$120,000
$126,000
$132,300
$138,915
100.00% $120,000
$12,000
$500
$15,000
$5,000
$272,500
$13,625
$126,000
$18,000
$500
$2,000
$5,000
$277,500
$9,250
$132,300
$24,000
$500
$2,000
$5,000
$296,100
$7,403
$138,915
$30,000
$500
$2,000
$5,000
$315,330
$6,307
Note: Production at $600 per unit is assumed as follows
Year 1 – 20 units
Year 2 – 30 units
Year 3 – 40 units
Year 4 – 50 units
Total
$129,304
$517,215
$517,215
$84,000
$2,000
$21,000
$20,000
$1,161,430
Summary of System Design
Laptop
9
8
Freq =
7
Magnitude
Mag =
6
5
4
Power =
3
2
1
0
0
50
100
150
Frequency (cpm)
START
Amplifier
Fiter
EGG SYSTEM
STOP
SUMMARY
National Instruments
DAQ AI 16E
RESET