Transcript View Oral #3

A MR Compatible Pressure
Transducer with Data Acquisition
Software Program
Mark Crowe
Viral Patel
Advisor: Dr. David Pickens
Project Purpose

The goal of this project is to design and
build a pressure transducer to measure
vasodilation patterns in males with
hypersexuality disorder that can function in
a MR environment and also create a
software program for data acquisition and
storage.

Hypersexuality: seen as an out of
control pattern of sexual thinking and
acting, driven by anxiety reduction rather
than desire, as a disorder similar to
chemical addiction and closely related to
obsessive-compulsiveness, and as a
attributable to early childhood abuse
and/or neglect.
Project Background



Joint study between Department of Psychiatry
and Department of Radiology.
fMRI used to determine whether similar brain
regions are activated by visual, sexual, and drugrelated stimuli.
This study can lead to scientific information
concerning the cause and effect of pathological
hypersexuality.
fMRI

fMRI is a technique for determining
the region of the brain activated
due to physical sensation or
activity.


Based on increased blood flow
The active brain regions of these
patients will be compared sexual
arousal activation maps in normal
males.
Market Potential

This is a built-to-suit device and will only
be used for research purposes.



No opportunity for individual consumer sales.
An effort could be made to contact the largest
research sites for fMRI around the country.
Possible use for testing impotence

Requires input from urologists
Budget


Vanderbilt’s Department of Psychiatry provided:

$200 pressure transducer

$50 sphygmomanometer
Vanderbilt’s Department of Radiology provided:




Computer with DaisyLab installed
Oscilloscope
Plastic tubing
Any unforeseen costs will be covered by the Psychiatry
Dept.

Once project is shown to function properly, a new computer system
will be bought solely for the use of this study.
Experiment Structure
Stimulus
(Video)
Projected onto Screen
Subject watches video
while in MR magnet
Vasodilation occurs
Change of pressure in cuff
Project Schematic
Cuff
Pressure Transducer
Computer
Amplifier
Data Acquisition
Card
Calibration of Tranducer
Calibration of Pressure Transducer
Pressure (mm Hg)
20
40
60
80
100
120
140
160
180
Voltage (V)
0.3
0.59
0.93
1.29
1.6
1.95
2.28
2.64
2.97
Voltage (V)
Calibration with 20ft Tubing
y = 0.0168x - 0.0658
R2 = 0.9997
4
3
2
1
0
0
50
100
150
Pressure (mm Hg)
Change of 0.336 V for every 20 mm Hg increase
200
Project Description

The pressure transducer is
connected to the cuff and
to the gauge of a
sphygmomanometer.
Project Description


Pressure measurement from
transducer is sent to an amplifier
with a coaxial output for the
signal.
Signal sent to computer via data
acquisition chip.
Project Description



Pressure measurement from
transducer is sent to an amplifier
with a coaxial output for the
signal.
Signal sent to computer via data
acquisition chip.
DaisyLab program created to
acquire and store measurements.
Project Description



Pressure measurement from
transducer is sent to an amplifier
with a coaxial output for the
signal.
Signal sent to computer via data
acquisition chip.
DaisyLab program created to
acquire and store measurements.

Data acquired in real-time.
Project Description



Pressure measurement from
transducer is sent to an amplifier
with a coaxial output for the
signal.
Signal sent to computer via data
acquisition chip.
DaisyLab program created to
acquire and store measurements.


Data acquired in real-time.
Measurements and time of
occurrence stored in a text file for
later analysis with Microsoft Excel.
The MR environment

Effect of magnetic field on signal?

Will tubing cause problems with SNR?
Project Status



Pressure transducer
has been assembled
and calibrated.
A software program
has been created with
DaisyLab for data
acquisition.
Balloon Testing is
complete.
Project Status


Device tested on patient outside of MR
environment
Device tested on patient in MR
environment
Current/Future Work

Modifying software program so that ECG data can
also be recorded.


Construction of a container for the device
components.


Complete by March 15
Complete by March 15
Write program for
new computer