continuous wave doppler device group 16: abbas bandukwala padma chunduru chris harvey advisor: dr....
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Continuous Wave Continuous Wave Doppler DeviceDoppler Device
Group 16:Group 16:Abbas BandukwalaAbbas BandukwalaPadma ChunduruPadma Chunduru
Chris HarveyChris HarveyAdvisor: Dr. Raul GuzmanAdvisor: Dr. Raul Guzman
Project ObjectiveProject Objective
Design, build and test a system to Design, build and test a system to measure Doppler velocity waveforms measure Doppler velocity waveforms in ankle blood vesselsin ankle blood vessels
Improve current technologyImprove current technology Better signal qualityBetter signal quality Easier measurementEasier measurement
Peripheral Vascular Peripheral Vascular Disease (PVD)Disease (PVD)
Definition: restriction of blood flow to limbs Definition: restriction of blood flow to limbs due to narrowing or clogging of arteriesdue to narrowing or clogging of arteries
CausesCauses Common vascular diseasesCommon vascular diseases Artherosclerosis, aneurysms, venous thrombosisArtherosclerosis, aneurysms, venous thrombosis Distort normal blood pressure and flowDistort normal blood pressure and flow
At risk populationsAt risk populations >50 years old>50 years old SmokersSmokers DiabeticsDiabetics High blood pressure or high cholesterolHigh blood pressure or high cholesterol
Peripheral Vascular Peripheral Vascular Disease (PVD)Disease (PVD)
Incidence of PVDIncidence of PVD 1 in 20 people >50 years old = ~10 1 in 20 people >50 years old = ~10
million peoplemillion people 75% of cases go undiagnosed75% of cases go undiagnosed
Importance of DiagnosisImportance of Diagnosis PVD is a strong predictor of heart PVD is a strong predictor of heart
diseasedisease PVD patients are at a higher risk of PVD patients are at a higher risk of
stroke and heart diseasestroke and heart disease
Noninvasive Vascular Noninvasive Vascular Disease DiagnosisDisease Diagnosis
Disease diagnosis using noninvasive Disease diagnosis using noninvasive techniquestechniques Check for presence, location, severity of Check for presence, location, severity of
diseasedisease External diagnosis is quick, noninvasiveExternal diagnosis is quick, noninvasive Screen high-risk patient populationsScreen high-risk patient populations Goal: reduce the number of Goal: reduce the number of
undiagnosed cases of PVDundiagnosed cases of PVD ~50 screenings/month or ~600 ~50 screenings/month or ~600
screenings/year at the Vanderbilt screenings/year at the Vanderbilt University Vascular LabUniversity Vascular Lab
Noninvasive Noninvasive MeasurementMeasurement
Blood pressure Blood pressure cuff occlusion cuff occlusion techniquetechnique
Doppler velocity Doppler velocity waveforms are waveforms are measured at DP measured at DP and PT arteries and PT arteries in anklein ankle
medicine.ucsd.edu/clinicalmed/ extremities.htm
www.curtin.edu.au/.../podiatry/ encyclopedia/vasdisease/
For the DP, the pulse felt on the top of the For the DP, the pulse felt on the top of the foot, between the first and second metatarsal foot, between the first and second metatarsal bones. In 8 to 10 per cent of the population this bones. In 8 to 10 per cent of the population this pulse cannot be detected. (www.WebMD.com)pulse cannot be detected. (www.WebMD.com)
Noninvasive Noninvasive Measurement for DPMeasurement for DP
http://www.csuchico.edu/phed/atc/Foot/PostTibArtery.jpg
Noninvasive Noninvasive Measurement for PTMeasurement for PT
Doppler Velocity Doppler Velocity WaveformsWaveforms
Triphasic, Normal
Biphasic, Abnormal
Monophasic, Abnormal
Doppler TheoryDoppler Theory
Measures velocityMeasures velocity 2 piezoelectric 2 piezoelectric
crystalscrystals Transmitting, Transmitting,
receivingreceiving Change in Change in
frequency due to frequency due to movement of red movement of red blood cellsblood cells
Crystals
RBCBlood Flow
Current Non - Invasive Current Non - Invasive Methods UsedMethods Used
Continuous Wave Continuous Wave Doppler PenDoppler Pen
PlethysmographyPlethysmography
Duplex Duplex UltrasonographyUltrasonography
Advantages/Advantages/DisadvantagesDisadvantages
Hard to locate proper vein Hard to locate proper vein or artery if blood velocity or artery if blood velocity is low.is low.
Must train person to use Must train person to use device.device.
User hand tied down with User hand tied down with devicedevice
Duplex ultrasound device Duplex ultrasound device is very large and expensiveis very large and expensive
Device is compatible with Device is compatible with all persons. all persons.
How we are going to go How we are going to go about solving the problem?about solving the problem?
Ace Bandage
Piezoelectric Crystals
Data Acquisit
ion & Analysis
High Pass & Amplifier circuit
Power Supply
A/D Converter
Advantages of Doppler Advantages of Doppler Array and LabView ProgramArray and LabView Program Cheap because it does not require Cheap because it does not require
trained crewtrained crew Easier to find signalEasier to find signal Better analysis of patient vascular system Better analysis of patient vascular system
in lower extremities in lower extremities Works on a high percentage of the Works on a high percentage of the
populationpopulation Universality of deviceUniversality of device User is able to perform multiple functionsUser is able to perform multiple functions
PartsParts
Doppler crystal Doppler crystal array ($45/crystal)array ($45/crystal)
Doppler pens Doppler pens ($100/pen)($100/pen)
ComputerComputer Connectors Connectors
(~$25/crystal)(~$25/crystal) A/D ConverterA/D Converter LabViewLabView
An Ace bandageAn Ace bandage Doppler GelDoppler Gel Doppler Audio Doppler Audio
Amplifier Amplifier Power supplyPower supply Op-amps, resistors, Op-amps, resistors,
capacitorscapacitors BreadboardBreadboard
Past WorkPast Work Investigation into the use of Doppler as a Investigation into the use of Doppler as a
means of vascular disease diagnosismeans of vascular disease diagnosis Research on the equipment necessary for Research on the equipment necessary for
data acquisitiondata acquisition Acquisition of equipmentAcquisition of equipment Multiple signals (waveform) can be Multiple signals (waveform) can be
displayed on LabView programdisplayed on LabView program LabView program can pick the signal with LabView program can pick the signal with
higher amplitudehigher amplitude
Current StatusCurrent Status
Development of LabView programDevelopment of LabView program Input of audio Doppler outputInput of audio Doppler output Display of signal on an oscilloscope in LabViewDisplay of signal on an oscilloscope in LabView Recording of data for analysis (of signal Recording of data for analysis (of signal
quality) quality) Highest Signal to Noise Ratio (SNR) Highest Signal to Noise Ratio (SNR)
Current StatusCurrent Status
Audio Doppler Box
LabView Program
A/D Converter
Doppler Pencil
Audio Doppler Box
FutureFuture
LabView changes to pick the higher LabView changes to pick the higher SNR as opposed to higher SNR as opposed to higher amplitudeamplitude
Working on crystals that can give Working on crystals that can give signal and can eventually be signal and can eventually be incorporated into an arrayincorporated into an array Increase sensitivity so the input signal Increase sensitivity so the input signal
can be perceivedcan be perceived