A MR Compatible Pressure A MR Compatible Pressure Transducer with Data Acquisition Transducer with Data Acquisition

Software ProgramSoftware Program

Mark CroweMark CroweViral PatelViral Patel

Advisor: Dr. David PickensAdvisor: Dr. David Pickens

Project PurposeProject Purpose

The goal of this project is to design The goal of this project is to design and build a pressure transducer to and build a pressure transducer to measure vasodilation patterns in measure vasodilation patterns in males with hypersexuality disorder males with hypersexuality disorder that can function in a MR environment that can function in a MR environment and also create a software program and also create a software program for data acquisition and storage. 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 BackgroundProject Background Joint study between Department of Joint study between Department of

Psychiatry and Department of Radiology.Psychiatry and Department of Radiology.

fMRI used to determine whether similar fMRI used to determine whether similar brain regions are activated by visual, brain regions are activated by visual, sexual, and drug-related stimuli. sexual, and drug-related stimuli.

This study can lead to scientific information This study can lead to scientific information concerning the cause and effect of concerning the cause and effect of pathological hypersexuality. pathological hypersexuality.

fMRIfMRI fMRI is a technique for fMRI is a technique for

determining the region of the determining the region of the brain activated due to physical brain activated due to physical sensation or activity.sensation or activity. Based on increased blood flowBased on increased blood flow

The active brain regions of The active brain regions of these patients will be these patients will be compared sexual arousal compared sexual arousal activation maps in normal activation maps in normal males. males.

Market PotentialMarket Potential This is a built-to-suit device and will This is a built-to-suit device and will

only be used for research purposes. only be used for research purposes. No opportunity for individual consumer No opportunity for individual consumer

sales.sales. An effort could be made to contact the An effort could be made to contact the

largest research sites for fMRI around the largest research sites for fMRI around the country.country.

Possible use for testing impotencePossible use for testing impotence Requires input from urologists Requires input from urologists

BudgetBudget Vanderbilt’s Department of Psychiatry provided:Vanderbilt’s Department of Psychiatry provided:

$200 pressure transducer$200 pressure transducer $50 sphygmomanometer$50 sphygmomanometer

Vanderbilt’s Department of Radiology provided:Vanderbilt’s Department of Radiology provided: Computer with DaisyLab installedComputer with DaisyLab installed OscilloscopeOscilloscope Plastic tubingPlastic tubing

Any unforeseen costs will be covered by the Psychiatry Any unforeseen costs will be covered by the Psychiatry Dept.Dept. Once project is shown to function properly, a new computer Once project is shown to function properly, a new computer

system will be bought solely for the use of this study.system will be bought solely for the use of this study.

Experiment StructureExperiment Structure

Stimulus(Video) Projected onto Screen

Subject watches video while in MR magnet

Change of pressure in cuff

Vasodilation occurs

Project SchematicProject Schematic

Cuff Pressure Transducer

Amplifier

Data AcquisitionCard

Computer

Calibration of TranducerCalibration of Tranducer

Calibration of Pressure Transducery = 0.0168x - 0.0658

R2 = 0.9997

01234

0 50 100 150 200

Pressure (mm Hg)

Vo

lta

ge

(V

)

Calibration with 20ft TubingPressure (mm Hg) Voltage (V)

20 0.340 0.5960 0.9380 1.29100 1.6120 1.95140 2.28160 2.64180 2.97

Change of 0.336 V for every 20 mm Hg increase

Project DescriptionProject Description

The pressure The pressure transducer is connected transducer is connected to the cuff and to the to the cuff and to the gauge of a gauge of a sphygmomanometer.sphygmomanometer.

Project DescriptionProject Description

Pressure measurement from Pressure measurement from transducer is sent to an transducer is sent to an amplifier with a coaxial amplifier with a coaxial output for the signal.output for the signal.

Signal sent to computer via Signal sent to computer via data acquisition chip.data acquisition chip.

Project DescriptionProject Description

Pressure measurement from Pressure measurement from transducer is sent to an transducer is sent to an amplifier with a coaxial amplifier with a coaxial output for the signal.output for the signal.

Signal sent to computer via Signal sent to computer via data acquisition chip.data acquisition chip.

DaisyLab program created to DaisyLab program created to acquire and store acquire and store measurements.measurements.

Project DescriptionProject Description Pressure measurement from Pressure measurement from

transducer is sent to an transducer is sent to an amplifier with a coaxial amplifier with a coaxial output for the signal.output for the signal.

Signal sent to computer via Signal sent to computer via data acquisition chip.data acquisition chip.

DaisyLab program created to DaisyLab program created to acquire and store acquire and store measurements.measurements. Data acquired in real-time.Data acquired in real-time.

Project DescriptionProject Description Pressure measurement from Pressure measurement from

transducer is sent to an transducer is sent to an amplifier with a coaxial output amplifier with a coaxial output for the signal.for the signal.

Signal sent to computer via Signal sent to computer via data acquisition chip.data acquisition chip.

DaisyLab program created to DaisyLab program created to acquire and store acquire and store measurements.measurements. Data acquired in real-time.Data acquired in real-time. Measurements and time of Measurements and time of

occurrence stored in a text file for occurrence stored in a text file for later analysis with Microsoft later analysis with Microsoft Excel.Excel.

The MR environmentThe MR environment

Effect of magnetic field on signal?Effect of magnetic field on signal?

Will tubing cause problems with Will tubing cause problems with SNR?SNR?

Project StatusProject Status

Pressure transducer Pressure transducer has been assembled has been assembled and calibrated.and calibrated.

A software program A software program has been created has been created with DaisyLab for with DaisyLab for data acquisition.data acquisition.

Balloon Testing is Balloon Testing is complete.complete.

Project StatusProject Status

Device tested on patient outside of Device tested on patient outside of MR environmentMR environment

Device tested on patient in MR Device tested on patient in MR environmentenvironment

Current/Future WorkCurrent/Future Work Modifying software program so that ECG Modifying software program so that ECG

data can also be recorded.data can also be recorded. Complete by March 15Complete by March 15

Construction of a container for the device Construction of a container for the device components.components. Complete by March 15Complete by March 15

Write program for Write program for

new computernew computer