Project Proposal

Final Year Project Y05

Project Proposal (updated) for

Portable cerebral blood clot detection

By

050001A G.K.I. Abeyrathna

050131V G. Gartheeban

050234N E.D.R. Kumara

050440R W.M.D. Soysa

Supervised By

Dr. A.A. Pasqual

Department of Electronics & Telecommunication

University of Moratuwa

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Approval Form

I hereby certify that I accept this project as the final year project of Group – 20 which

will come under my supervision.

……………………………………………

Dr. A.A. Pasqual

B.Sc. Eng.(Moratuwa), M.Eng.(Tokyo), Ph.D(Tokyo), MIEEE, MACM

Senior Lecturer

Department of Electronic and Telecommunication Engineering

University of Moratuwa

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Contents

Introduction .......................................................................................................................... 1 Classification ......................................................................................................................... 2 Objectives ............................................................................................................................... 3 Justification ............................................................................................................................ 3 Literature survey ................................................................................................................. 4 References …….......................................................................................................... 5 Analysis ....................................................... .........................................................,….. 5 Scope ......................................................................................................................................... 8 Possible resource requirements ................................................................................... 8 Basic architecture and required methodologies .................................................... 9 Timeline………………………………………..…………………………………………………. 12

1

Introduction

Hematoma, the collection of blood, generally the result of hemorrhage, also known

as, internal bleeding may, at times, be fatal. Hematomas may exist as bruises on outer

skin but when they develop in organs require extra attention. In most cases the sac of

blood eventually dissolves; however, in some cases they may continue to grow, and fatal

especially if it is cerebral.

Intracranial hemorrhage or brain damages caused by traumatic brain injuries cause the

following types of cerebral hemorrhages.

Intra-axial hemorrhage

Extra-axial hemorrhage

o Subgaleal hematoma — between the galea aponeurosis & periosteum

o Cephalhematoma — between the periosteum & skull

o Epidural hematoma — between the skull & dura mater

o Subdural hematoma — between the dura mater & arachnoid mater

o Subarachnoid hematoma — between the arachnoid mater and pia

mater (the subarachnoid space)

Intra cerebral hemorrhages are mostly untreatable

and Subgaleal hematoma and Cephal hematoma are

less dangerous compared to the other three as they

happen outside the skull.

Epidural hematoma is a buildup of blood occurring between the Dura

mater (the brain's tough outer membrane) and the skull. The condition is potentially

deadly because the buildup of blood may increase pressure in the intracranial space and

compress delicate brain tissue. The condition is present in one to three percent of head

injuries. Between 15 and 20% of patients with epidural hematomas die of the injury.

Subarachnoid blood clot usually happens in the setting of other traumatic brain

injury and has been linked with a poorer prognosis. It is unclear; however, if this is a

direct result of the SAH or whether the presence of subarachnoid blood is simply an

indicator of severity of the head injury and the prognosis is determined by other

associated mechanisms.

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Subdural hematoma is a form of traumatic brain injury in

which blood gathers between the dura and

the arachnoid (the middle layer of the meninges). Unlike

in epidural hematomas, which are usually caused by tears

in arteries, subdural bleeding usually results from tears in

veins that cross the subdural space. This bleeding often

separates the dura and the arachnoid layers. Subdural

hemorrhages may cause an increase in intracranial

pressure (ICP), which can cause compression of and

damage to delicate brain tissue. Acute subdural hematoma

(ASDH) has a high mortality rate and is a severe medical

emergency.

The early detection of the aforementioned blood clots is paramount, and will be a life

saver. Currently only Computer Tomography (CT scan) is capable of identifying it,

nonetheless unfortunately, it is prohibitively expensive and rarely available.

The project was proposed by Dr. A. A. Pasqual, and requires some extensive analysis

into the problem involving multiple domains, such as neurology, Traumatic Brain Injury

(TBI) / brain surgery, sensor technologies, micro controller programming, embedded

application development and electronic circuits.

Classification

This project idea was proposed by Dr A. A. Pasqual and is mainly focused on providing a

solution to early detection of cerebral blood clots. This involves a significant amount of

research, hence comes under product development with research component, under the

departmental classification of final year projects.

1 Subdural hematoma

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Objectives

Our objective is to enable the availability of a portable, inexpensive robust unit for

early detection of extra cerebral blood clots that could be used for pre-examination

before CT scan test is scheduled.

The core purpose, we undertook this project for, is to

provide a system for early detection of blood clots that

would help reducing fatalities on aftermath of accidents.

We find the limited availability of CT scanners the crux of

all the problems that needs to be addressed. The

availability of pre-examination and detection will lead to

the efficient utilization of CT scanners.

For instance, on the occurrence of such an injury, this

portable device could be used to ensure the presence of

blood clots and alert the immediate attention required. If

CT scanner is available, the patient can be moved up in

the queue for CT scan on the positive detection using such a unit, otherwise this could

be used as a simple substitute for CT scan and with thorough checking the exact location

could be identified and operated.

We believe this is an opportunity for us to serve the community by providing a solution

to a much needed problem, which is the bottom line of our objective.

Justification

This is one of the highly sought after technology in the field of medicine and the

bestowment of noble prize for the invention of CT scanner proves the supreme

importance of it. The importance of early detection of cerebral blood clots is thus

obvious. The proposed project clearly addresses the above mentioned detection

requirement.

The benefits of the proposed solution will be huge and disreputable and they are

analyzed below in terms of the reduction of hazardous effects, and economics and

logistics concerns.

CT scan is regarded as a moderate to high radiation diagnostic technique. While

technical advances have improved radiation efficiency, there has been simultaneous

2pie chart showing head injury fatalities by percentage of causes

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pressure to obtain higher-resolution imaging and use more complex scan techniques,

both of which require higher doses of radiation. Head CT scan normally generates 1.5

mSv dose of radiation. Increased CT usage has led to an overall rise in the total amount

of medical radiation used, despite reductions in other areas. Statistics show that, in the

United States and Japan, there were 26 and 64 CT scanners per 1 million populations in

1996. In the U.S., there were about 3 million CT scans performed in 1980, compared to

an estimated 62 million scans in 2006 which emphasize the need of a pre-examination

technology to sort out, prioritize and avoid the use of CT scan unnecessary, which will

enhance the utilization of CT scanners especially in developing and under developed

countries where there is a great demand and long waiting list for.

Amber diagnostics radiology equipment sales quote the minimum prize at 2.2 million

USD for CT scanner. Further it is notable that from 1974 to 2004, the list price of a CT

scanner has gone up faster than inflation (from $385K to $2200K, 471% increase,

versus 342% increase in consumer price index). This sends the ‘clarion call’ for a need

of an inexpensive unit that could give a true / false trigger as a pre-detection technology

or a perfect substitute for CT scanners.

The development of the proposed solution will involve knowledge and skills of multiple

study areas - the research into neurology, bio-medical sensor systems, development of

sensor system, microcontroller programming, embedded application development,

algorithm development, and electronic and product design and realization. We believe

the scope and depth of the project and the technical complexity required would be quite

challenging and more than sufficing for a final year project.

Literature survey

The research to find alternatives for CT scan has started long time back, and has begun

to show promising results. It will be an important source of information for the

development of sensor systems. Neurology online [1] and American academy of

neurology [2] are the two ultimate sources for information pertained to the medical

aspects of cerebral hemorrhage.

Near Infra-Red spectroscopy is one of the area that is being research and found to be

ideal. “Use of near infrared spectroscopy to identify traumatic intracranial hematomas."

by C. S. Robertson, S. P. Gopinath, and B. Chance also seems to be encouraging.

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As an alternative technology ultrasonic sensors have also been considered and it is

found that solutions have been developed to detect blood clots/air bubbles in arteries.

However NIRS remains ultimate answer to the call due to several other limitations.

References

[ 1 ] Neurology Online,

http://www.neurology.org/cgi/collection/intracerebral_hemorrhage, last

accessed 2009, June

[ 2 ] American Academy of Neurology, http://www.aan.com, last accessed 2009, June

[ 3 ] Gopinath SP, Robertson CS, Grossman RG, Chance B., "Near-infrared

spectroscopic localization of intracranial hematomas." J Neurosurg 1993 Jul;

79(1): 43-47.

[ 4 ] Gopinath SP, Robertson CS, Grossman RG, Chance B., "Near-infrared

spectroscopic localization of intracranial hematomas." Comment in J

Neurosurg. 1994 Jan; 80(1): 181-182.

[ 5 ] S.P. Gopinath, B. Chance, and C.S. Robertson, "Near-infrared spectroscopy in

head injury”. Chap. 12 in Neurotrauma, R.K. Narayan, J. Wilberger, and J.

Povlishock. Eds., pp. 169-184, McGraw-Hill, New York, NY (1994).

[ 6 ] Robertson CS, Gopinath SP, Chance B., "A new application for near-infrared

spectroscopy: detection of delayed intracranial hematomas after head injury." J

Neurotrauma 1995 Aug; 12(4); 591-600.

[ 7 ] Gopinath SP, Robertson CS, Contant CF, Narayan RK, Grossman RG, Chance B.,

"Early detection of delayed traumatic intracranial hematomas using near-

infrared spectroscopy." J Neurosurg 1995 Sep; 83(3): 438-444.

[ 8 ] C. S. Robertson, S. P. Gopinath, and B. Chance, "Use of near infrared spectroscopy

to identify traumatic intracranial hematomas." J. Biomed. Opt. 2, 31–41 (1997).

[ 9 ] C. S. Robertson, S. P. Gopinath, and B. Chance, "Identifying intracracranial

hematomas with near-infrared spectroscopy." in Transcranial Cerebral

Oximetry, G. Litscher and G. Schwarz. Eds., pp. 131–141, Pabst Science, Berlin

(1997).

[ 10 ] Zhang Q, Ma H, Nioka S, Chance B., "Study of near infrared technology for

intracranial hematoma detection." J. Biomed. Opt. 5, 206-213 (2000).

Analysis

Both the technologies we looked into were noninvasive, and first between them was

ultrasonic Doppler Effect. This has been primarily used for blood parameter detection

such as speed of the cells, congestion, etc. Professor David H Evans and Professor A Ross

Naylor in the Department of Cardiovascular Sciences at the University of Leicester

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developed a technique involving the use of Doppler ultrasound for emboli detection.

The work was recently presented at an international conference on Ultrasound in

Medicine in Australia. In the case of emboli detection, the 'transducer' is placed on the

side of the patient's head, just in front of the ear, and is used to detect the movement of

emboli through blood vessels in the brain. The technique is painless and harmless.

Patients undergoing various types of operation have this small ultrasound transducer

attached to the side of their head to give early warning of embolism occurring. Although

this is particularly useful in the event of embolism occurring which is common in a post-

surgery, impractical for TBI due to requirement of particle movements which maybe

absent in extra cerebral hemorrhage.

The second method uses Near Infrared

Spectroscopy (NIRS) which has many

interesting properties related to the

absorption by various chemicals. Research in

the field of near infrared spectroscopy NIRS

for measuring tissue properties dates back to

Millikan, who first developed a dual

wavelength muscle oximeter, and Jobsis who

was the first to note that the spectral

absorption of both hemoglobin and

cytochrome aa3 could be observed in vivo

with near infrared transillumination.

Intracranial hematoma detection is one of the

most basic and important applications of near

infrared spectroscopy. The basic principle of

hematoma detection with NIRS is that water

absorption in the near infrared range is

relatively small and hemoglobin contributes to most of the tissue absorption; extra

vascular blood absorbs NIR light more than

normal brain tissue since there is a greater

concentration of hemoglobin in an acute

hematoma. By comparing the re reflected and

diffusing optical signal I2 from the suspicious

hematoma side and I1 from the healthy side

or from a standard model, the optical density

OD be calculated:

OD = log (I1 /I2)

Also we hope, from continuous use of the unit we could come up with a statistical

pattern that will also help finding coarse detection which can be used to raise an alert

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and differential reflection can be used to obtain acute results. The following graphs [8]

illustrate significant difference in OD caused by hemorrhage.

A single NIRS examination reliably identifies patients with an intracranial hematoma

(98% had a ΔOD > 0.05), and gives a suggestion of whether the hematoma was

intracerebral (most had a ΔOD <0.6) or extracerebral (most had a ΔOD >0.6).

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Scope

The project will focus on developing a unit for detection of the presence of blood clots at

a particular location particularly extra cerebral. The unit will be able to indicate the

existence, however wouldn’t be able to guarantee the non-existence which will require

years of experience of analyzing the data displayed by the system.

The unit is expected to be capable of detecting the following three types of extra

cerebral blood clots.

Epidural hematoma

Subarachnoid hematoma

Subdural hematoma

However aforementioned corresponds to the most of the reported cases that led to

death due to extra cerebral hemorrhages, and intra cerebral hemorrhages are yet

inoperable.

The system will be able to show quick indication from past statistics and detailed

illustration in an embedded device such as smart phone or PDA through Bluetooth. The

delivered solution will be portable, inexpensive and real time.

Possible resource requirement:

Sensor requirement – Infrared transmitter/receivers

Controller requirement – Microcontroller with Bluetooth support

IO system requirement – Embedded system; a mobile phone or a PDA

Other requirements – A sample space of patients taking CT scan test

The CT scan reports of those patients

Resource person with medical academic background

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Basic Architecture and required methodologies

The above block diagram shows the basic architecture of the system that we intend to

implement during the final year project.

The Transmission subsystem

This sub-system will be responsible for the generation and

transmission of the NIR signals. The control circuit receives its

input from the micro-controller and hence enables finer

control over the strength of the transmission signal. A pulsed

driving circuit drives the LED light source. The current control

circuit can either be a DAC or a voltage divider. According to the command given by the

microcontroller, it generates different control voltages to adjust the light intensity.

The receiver subsystem

The reception of the reflected diffusing light

signal will be detected by the photodiode.

The received signal is amplified and the

output of the amplifier is fed to the ADC.

Controller subsystem

The controlling subsystem will be implemented through a micro-controller. The

microcontroller is in charge of the whole operation, which includes acquiring the signal,

calculations, adjusting the incident light intensity, and communicating the output.

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ADC

During the light pulse off period, the detected signal,

which is actually ‘‘dark current’’ or background light, is

sampled and held for dark signal correction. During the

light pulse on period, the reflected diffusing light signal

detected by the photodiode is amplified and also input

into the ADC. Since the ADC is working in a differential

input state, the dark voltage is subtracted from the light

voltage; the corrected signal is amplified inside the

ADC, then digitized, and finally transported to the

microcontroller. The ADC communicates with the microcontroller through a serial port.

Operation

With specified wavelength ranges, optical light source and photo detector are placed at

a distance, which allows proper NIRS absorption measurements in a desired volume of

tissue. The NIRS probe is placed successively in the left and right frontal, temporal,

parietal, and occipital areas of the head and the absorbance of light at selected

wavelengths is recorded.

LEFT SIDE RIGHT SIDE

Frontal Left/Right forehead, above the frontal sinus

Temporal In the Left/Right temporal fossa

Parietal Above the Left/Right ear, midway between the ear and the midline

of the skull

Occipital Behind the Left/Right ear, midway between the ear and the

occipital protuberance

The results are analyzed differentially and OD is found. Further from the reception

levels and ODs for various wavelengths will be recorded.

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Input-Output subsystem

The microcontroller will be interfaced with the IO

subsystem, through a wireless technology like Bluetooth.

The IO subsystem would involve a display of the NIR

image, and the regions with the possibility of blood clots.

The IO subsystem will be built on a mobile device like a

mobile phone or a PDA.

It is hoped to produce two levels of outputs. First from the

statistical learning, upon the reception of a critical value

red alert can be triggered with an LED indication. This will

be independent of person but depending on the location of

the detection (F / T / P / O).

The second is the mapping of the spectrographic analysis from the differential obtained.

We hope to export the data to an embedded device such as a PDA through Bluetooth,

perform the computation and display the results through an embedded application

running.

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Timeline