Biomedical Engineering (Full Details) - Mathankumar.S - VMKVC, SALEM, TAMILNADU

1. 7/25/2014 1

2. 2/1/2015 2
Solving problems in biology and
medicine using engineering methods
and technology (e.g., research, design
and development of biomedical
instrumentation.)

3.  Image is an Artifact that
reproduce the likeness of
some subjects usually a
physical object.

4.  Images are pictures!
A picture that represents visual
information.
 Used to save visual experiences.
 A picture is worth a 1000 words…I
think more!!!
 How are non-digital images stored?
Photographic film
Canvas/paint
Digitally

5.  Imaging is the process of acquiring images.
 Shorthand for image acquisition.
 Process of sensing our surroundings and then
representing the measurements that are made in
the form of an image.

6.  Passive imaging – employs energy sources
that are already present in the scene.
 Active imaging – involves use of artificial
energy sources to probe our surroundings.
6

7.  Passive imaging is subject to the limitations of
existing energy sources.
Passive Imaging

8.  Active imaging is not restrictive in this way
but is invariably a more complicated &
expensive procedure.
 Active imaging predominates in medical field,
where precise control over radiations sources
is essential.
 Active imaging is also an important tool in
remote sensing.
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Active Imaging

9. DICOM - Digital Imaging and Communications in Medicine
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10. 10

11.  User Consortia (e.g., HL7)
 Organizations (e.g., NEMA, IEEE)
 US Government Agencies (e.g., ANSI, NIST)
 Foreign Government Agencies (e.g., CEN)
 United Nations (e.g., ISO, CCITT)

12.  The name was changed to separate the standard
from the originating body
 1991 - Release of Parts 1 and 8 of DICOM
 1992 - RSNA demonstration, Part 8
 1993 - DICOM Parts 1-9 approved,
RSNA demonstration of ALL parts
 1994 - Part 10: Media Storage and File Format
 1995 - Parts 11,12, and 13 plus Supplements

13. MAGN
ETOM
Information Management System
Storage, Query/Retrieve,
Study Component
Query/Retrieve, Patient & Study Management
Query/Retrieve
Results Management
Print Management
Media Exchange
LiteBox

14. SOP
Data Dictionary
Real-World Object
Information Object DIMSE Service Group

15.  Composite
Verification
Storage
Query/Retrieve
Study Content Notification
 Normalized
Patient Management
Study Management
Results Management
Basic Print Management

16.  Joint CEN-DICOM development
 Medicom = DICOM
 MIPS 95 work is underway with JIRA
 IS&C Harmonization is also in progress
 HL7 Harmonization continuing interest
 New DICOM organization
 Companies: NEMA and non-NEMA
 ACR, ACC, CAP, ...
 individuals

17. Networking is a critical component of all
medical imaging systems
Support for Open Communication Standards is a
MUST
DICOM is here, NOW
DICOM products exist on the market
DICOM is emerging as THE common protocol for
medical image communication - WORLD WIDE!

18. Electro-Magnetic Spectrum

19. IR Imaging (Performance)
Fig. Thermal / IR view of a Chip

20. IR Imaging (Natural Calamity)
Fig. IR satellite view
of Augustine volcano

21. IR Imaging (Night Vision)
Fig. IR image of a sloth at night

22. IR Imaging (Night Vision)
Fig. Night vision system used by soldiers

23. Ultrasound imaging (Medical)
Fig. Fetus and Thyroid using ultrasound

24. Seismic imaging (Earthquake)
Fig. Detecting Earthquakes and its cause using cross
sectional view

25. UV imaging (Ozone)
Fig. Detect ozone layer damage

26. X-Ray imaging (Medical)
Fig. X - Ray of neck

27. X-Ray imaging (Medical)
Fig. X - Ray of head

28. Gamma-Ray imaging (Medical)
Fig. Gamma ray exposed images

29. Remote Sensing
Fig. Satellite images of Mumbai suburban(Left) and Gateway of India
(Right)

30.  Images stored in digital form!
Many ways of acquiring images
Scanner
Digital Camera
Others…
Many ways of storing images
Gif
Tiff
BMP
JPG
Others…

31. JPEG (Joint Photographic Experts Group)
GIF (Graphic Interchange Format)
PNG (Portable Network Graphics)
TIFF (Tagged Image File Format)
PGM (Portable Gray Map)
FITS (Flexible Image Transport System)
BMP (Bitmap Format)

32. JPEG - Joint Photographic Experts Group
JPEG is designed with photographs in mind.
 It is capable of handling all of the colors needed.
JPEGs have a lossy way of compressing images.
At a low compression value, this is largely not
noticeable, but at high compression, an image can
become blurry and messy. .jpg

33. JPEG cautions:
• Images with hard edges, high contrasts, angular areas, and
text suffer from JPEG compression.
• Scanned “natural” photographs do not lose much,
especially at High or Maximum quality.
• Only save finished images as JPEGs, every time you open
and save again, even if you don’t edit, you lose quality.
• Always keep the original non-JPEG version (the native .psd
format).
So why use JPEG?
• It is the best format for photographic images on the Web.
• It’s compression ability is very great.

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35. GIF - Graphics Interchange Format
GIF is the most popular on the Internet, mainly because of its
small file size. It is ideal for small navigational icons and simple
diagrams and illustrations where accuracy is required, or
graphics with large blocks of a single color. The format is loss-
less, meaning it does not get blurry or messy.
The 256 color maximum is sometimes tight, and so it has the
option to dither, which means create the needed color by
mixing two or more available colors.
GIF use a simple technique called LZW compression to reduce
the file sizes of images by finding repeated patterns, but this
compression never degrades the image quality.
.GIF

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 The GIF format is one of the most commonly used
graphic file formats, especially on the Internet.
 The GIF format is exceedingly useful in that it can
contain animations. Its internal structure is such
that it can store multiple images and the controls to
make them appear as real time animation
 animated GIF.
 The GIF format also allows a special color as to be
specified as "using the background." This results in
the image looks like transparent
 transparent GIF.

37. 37
 Portable Network Graphic (PNG) which is
pronounced as “Ping”.
 Alternative to GIF, a lossless compression
scheme is used.
 Support three image type: true color,
grayscale, palette-based (8-bit).
 JPEG supports the first 2.
 GIF supports the 3rd one.

38. 38
 Advantages
 Better Compression
○ Deflate is an improved version of the Lempel-Ziv compression
algorithm.
 Improve Interlacing
○ Display image quicker than Interlaced GIF.
 True Color and Transparency
○ Support 16-bit (Grey scale) or 48-bit (True Color)
○ 16-bit for alpha channel (Transparency).
 Gamma storage
○ Store the gamma setting of the platform of the creator.
 Disadvantages
 Not support by old browsers (Netscape 2,3,4 and IE 2,3,4)

39. TIFF - Tagged Image File Format
 Widely used cross platform file format also designed for printing.
 A bitmap image format.
 TIFF supports lossless LZW compression which also makes it a
good archive format for Photoshop documents.

40.  A popular format for grayscale images (8 bits/pixel)
 Closely-related formats are:
 PBM (Portable Bitmap), for binary images (1 bit/pixel)
 PPM (Portable Pixelmap), for color images (24 bits/pixel)
- ASCII or binary (raw) storage

41. FITS - Flexible Image Transport System
 Format of a FITS file (http://fits.gsfc.nasa.gov)
 Primary Header: metadata describing
instrument, observation & file contents
 Primary Data Array: array of 0-999
dimensions – usually a 2D image
+ none or more Extensions:
 Array, ASCII Table or Binary Table, each with
Header
(New FITS-inspired XML format – VOTable)

42. 42
BMP - Bitmap Format
uses a pixel map which contains line by line information.
It is a very common format, as it got its start in Windows.
 This format can cause an image to be super large.

43. Image Processing is any form of signal processing for
which our input is an image, such as photographs or
frames of video and our output can be either an image or
a set of characteristics or parameters related to the
image.

44.  Image Processing generally refers to processing
of two dimensional picture and by two
dimensional picture we implies a digital image.
 A digital image is an array of real or complex
numbers represented by a finite number of bits.
 But now in these days optical and analog image
processing is also possible.

45.  Is enhancing an image or extracting information
or features from an image.
 Computerized routines for information extraction
(eg, pattern recognition, classification) from
remotely sensed images to obtain categories of
information about specific features.

46. Image processing are of two
aspects..
improving the visual appearance
of images to a human viewer
preparing images for
measurement of the features
and structures present.
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47. ❶ Acquisition of Image
 Medical image data is acquired one slice at a time.
 Resulting data set comprises n slices, each containing w x h
pixels.
Basic Steps for Image Processing

48. ❷ Data Storage
 Array starts with the first row of the first slice and so on until the end of
the first slice.
 Next, the array continues with the first row of the second slice, then the
second row of the second slice, and so on.

49.  A single slice corresponds to a k
space plane acquired in real-time
 The “K-Space” undergoes an Inverse
Fourier Transform.
 Following this mathematical step,
we finally have an image
❸ Image Formation

50. ❹ Data Visualisation
 Medical image data is commonly visualised by two
methods.
 Reslicing
 Surface rendering

51. Since the digital image is “invisible” it must be
prepared for viewing on one or more output
device (laser printer, monitor, etc.,)
It might be possible to analyze the image in the
computer and provide cues to the radiologists to
help detect important/suspicious structures (e.g.:
Computed Aided Diagnosis, CAD)
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Why do we need Image Processing

52. Image processing can be done using various
software's and languages such as:-
Language
VHDL
C/C++
Software
Matlab
Adobe Photoshop
Irfan view
How Image Processing is done?

53. 53
 Early 1920’s: One of the first applications of digital
imaging was in the newspaper industry
 The Bartlane cable picture
transmission service
 Images were transferred by
submarine cable between London
and New York
 Pictures were coded for cable
transfer and reconstructed at the
receiving end on a telegraph printer
Early digital image

54.  Mid to late 1920’s: Improvements to the Bartlane
system resulted in higher quality images
Improved
digital image Early 15 tone digital
image
New reproduction processes
based on photographic
techniques
Increased number of tones in
reproduced images

55. 1960’s: Improvements in computing technology
and the onset of the space race led to a surge of
work in digital image processing
A picture of the moon taken
by the Ranger 7 probe
minutes before landing
 1964: Computers used to
improve the quality of images of
the moon taken by the Ranger 7
probe
 Such techniques were used in
other space missions including
the Apollo landings

56. 1970’s: Digital image processing begins to be
used in medical applications
Typical head slice CAT
image
1979: Sir Godfrey N. Hounsfield & Prof.
Allan M. Cormack share the Nobel Prize
in medicine for the invention of
tomography, the technology behind
Computerised Axial Tomography (CAT)
scans

57. 1980’s - Today: The use of digital image processing
techniques has exploded and they are now used for all kinds
of tasks in all kinds of areas
 Image enhancement/restoration
 Artistic effects
 Medical visualisation
 Industrial inspection
 Law enforcement
 Human computer interfaces

58.  Face detection
 Feature detection
 Non-photorealistic rendering
 Medical image processing
 Microscope image processing
 Morphological image processing
 Remote sensing
 Automated Sieving Procedures
 Finger print recognization
Applications

59.  Primary purpose is to identify pathologic conditions.
 Requires recognition of normal anatomy and
physiology.
 Create image of body part
 Disease Monitoring

60. Medical imaging is the technique and
process used to create images of
the human body or it’s parts for clinical
purposes .
Non-invasive visualization of internal
organs, tissue, etc.

61.  Medical imaging has come a long way since 1895
when Röntgen first described a ‘new kind of ray’.
 That X-rays could be used to display anatomical
features on a photographic plate was of immediate
interest to the medical community at the time.
 Today a scan can refer to any one of a number of
medical-imaging techniques used for diagnosis and
treatment.
Medical Imaging using Ionising Radiations

62.  The transmission and detection of X-rays still lies at the heart of
radiography, angiography, fluoroscopy and conventional
mammography examinations.
 However, traditional film-based scanners are gradually being
replaced by digital systems
 The end result is the data can be viewed, moved and stored without
a single piece of film ever being exposed.
Digital Systems

63. Projection X-ray (Radiography)
Ultrasound
X-ray Computed Tomography (CT)
Magnetic Resonance Imaging(MRI)

64. 1. X-Rays
2. Computer Tomography (CT or CAT)
3. MRI (or NMR)
4. PET / SPECT (Positron Emission Tomography,
Single Photon Emission Computerized Tomography

65. 5. Ultrasound
6. Computational
7. Mammography
8. Angiography
9. Fluoroscopy
65

66. X-rays: A form of Electromagnetic
Energy travelling at the speed of
light.
Properties
*No mass *No charge *Energy
Wavelength – Range of 0.01 to 10
nanometer

67.  X-rays: a form of electromagnetic energy
 Travel at the speed of light
 Electromagnetic spectrum
 Gamma Rays X-rays
 Visible light Infrared light
 Microwaves Radar
 Radio waves

68.  X-Rays are associated with inner shell electrons
 As the electrons decelerate in the target
through interaction, they emit electromagnetic
radiation in the form of x-rays.
 patient is located between an x-ray source and
a film -> radiograph
 cheap and relatively easy to use
 potentially damaging to biological tissue

69. X-Rays - Visibility
 Bones contain heavy atoms -> with many electrons,
which act as an absorber of x-rays
 Commonly used to image gross bone structure and
lungs
 Excellent for detecting foreign metal objects
 Main disadvantage -> Lack of anatomical structure
 All other tissue has very similar absorption
coefficient for x-rays

70. Three things can happen
 X-rays can:
 Pass all the way through the body
 Be deflected or scattered
 Be absorbed
Where on this image
have x-rays passed
through the body
to the greatest degree?

71. X-rays Passing Through Tissue
 Depends on the energy of the x-ray
and the atomic number of the tissue
 Higher energy x-ray - more likely to
pass through
 Higher atomic number - more likely
to absorb the x-ray

72.  X-rays that pass through the body to
the film render the film dark (black).
 X-rays that are totally blocked do not
reach the film and render the film
light (white).
Air = low atomic no. = x-rays get through
= image is dark
Metal = high atomic no. = x-rays blocked
= image is light (white)
How do x-rays passing through
the body create an image?

73. 5 - Basic Radiographic Densities
 Air
 Fat
 Soft tissue/fluid
 Mineral
 Metal
1.
2.
3.
4.
5.

74. X-Rays - Images
X-Rays can be used in computerized tomography

75.  Computerized (Axial) Tomography
 Introduced in 1972 by Hounsfield and Cormack
 Natural progression from X-rays
 Based on the principle that a three-dimensional object can be
reconstructed from its two dimensional projections
From 2D to 3D !
Radon again!
CT (or) CAT

76. • Johan Radon (1917) - Showed how a reconstruction from
projections was possible.
• Cormack (1963,1964) - Introduced Fourier transforms into the
reconstruction algorithms.
• Hounsfield (1972) - Invented the X-ray Computer scanner for
medical work, (which Cormack and Hounsfield shared a Nobel
prize).
• EMI Ltd (1971) - Announced development of the EMI scanner
which combined X-ray measurements and sophisticated
algorithms solved by digital computers.

77.  measures the attenuation of
X-rays from many different angles
 a computer reconstructs the
organ under study in a series of
cross sections or planes
 combine X-ray pictures from
various angles to reconstruct 3D
structures

78.  Linear advancement (slice by slice)
 typical method
 tumor might fall between ‘cracks’
 takes long time
 Helical movement
 5-8 times faster
 A whole set of trade-offs

79. 1. Scanning the patient
2. Data Acquisition
 Tube and detector move
 Multiple attenuation
measurements are taken
around object.
3. Image reconstruction
4. Image Display
5. Image archival (recording)

80.  Conventional CT
 Axial
 Start/stop
1.X-ray tube and detector rotate 360°
2.Patient table is stationary with X-ray’s “on”
3.Produces one cross-sectional image
4. Once this is complete patient is moved to
next position
Process starts again at the beginning
1.X-ray tube and detector rotate 360°
2.Patient table moves continuously
With X-ray’s “on”
3.Produces a helix of image information
4.This is reconstructed into 30 to 1000 images
 Volumetric CT
 Helical or spiral CT
 Continuous acquisition

82. One 256-Slice CT Scan
256 x 0.5 MB = 178 MB

83. Medical Applications Type of Tomography
Full body scan X-ray
Respiratory, digestive systems,
brain scanning
PET Positron Emission
Tomography
Respiratory, digestive systems. Radio-isotopes
Mammography Ultrasound
Whole Body Magnetic Resonance (MRI, NMR)
PET scan on the
brain showing
Parkinson’s
Disease
MRI and PET showing
lesions in the brain.

84. Non Medical Applications Type of Tomography
Oil Pipe Flow
Turbine Plumes
Resistive/Capacitance
Tomography
Flame Analysis Optical Tomography
ECT on industrial pipe flows

85.  Significantly more data is collected
 Superior to single X-ray scans
 Far easier to separate soft tissues other than bone from one
another (e.g. liver, kidney)
 Data exist in digital form -> can be analyzed quantitatively
 Adds enormously to the diagnostic information
 Used in many large hospitals and medical centers throughout
the world

86.  significantly more data is collected
 soft tissue X-ray absorption still relatively similar
 still a health risk
 MRI is used for a detailed imaging of anatomy – no X rays
involved.

87. 1979 “For the Development of
computer assisted tomography (CAT)”
– Hounsfield & Cormack
2003 “For the Discoveries
concerning magnetic resonance
imaging (MRI)” - Paul Lauterbur &
Peter Mansfield

88.  Nuclear Magnetic Resonance (NMR) (or Magnetic
Resonance Imaging - MRI)
 Most detailed anatomical information
 High-energy radiation is not used, i.e. this is “safe
method”
 Based on the principle of nuclear resonance
 (medicine) Uses resonance properties of protons
MRI (or) NMR

89. Magnetic resonance imaging (MRI),
Magnetic resonance imaging (MRI), is a
non-invasive method used to render
images of the inside of an object. It is
primarily used in medical imaging to
demonstrate pathological or other
physiological alterations of living tissues.

90. Hydrogen nuclei(protons) under a strong magnetic field in
phase with one another and align with the field.
Relaxed protons induce a measurable radio signal.
1952
 Main modality for image guided surgery.
 Ability to discriminate between subtle surfaces.
 Very safe.
--Not effective for bone scanning.

91.  Positron Emission Tomography
Single Photon Emission
Computerized Tomography
 recent technique
 involves the emission of particles of
antimatter by compounds injected
into the body being scanned
 follow the movements of the
injected compound and its
metabolism
 reconstruction techniques similar to
CT - Filter Back Projection & iterative
schemes

92. •Positron Emission Tomography
(PET) is a nuclear medicine medical
imaging technique which produces
a three-dimensional image or map
of functional processes or
Metabolic Activities in the body.

93. 93
To conduct the scan, a short-lived radioactive tracer isotope,
which decays by emitting a positron, which also has been
chemically incorporated into a metabolically active molecule,
is injected into the living subject (usually into blood
circulation).
The data set collected in PET is much poorer than CT, so
reconstruction techniques are more difficult (see section
below on image reconstruction of PET).

94.  the use of high-frequency sound (ultrasonic) waves to
produce images of structures within the human body
 above the range of sound audible to humans (typically
above 1MHz)
 piezoelectric crystal creates sound waves
 aimed at a specific area of the body
 change in tissue density reflects waves
 echoes are recorded

95.  Delay of reflected signal and amplitude determines the position of
the tissue
 still images or a moving picture of the inside of the body
 there are no known examples of tissue damage from conventional
ultrasound imaging
 commonly used to examine fetuses in utero in order to ascertain
size, position, or abnormalities
 also for heart, liver, kidneys, gallbladder, breast, eye, and major
blood vessels

96.  by far least expensive
 very safe
 very noisy
 1D, 2D, 3D scanners
 irregular sampling -
reconstruction
problems

97. 97

98.  Mammography is a radiographic examination that is
specially designed for detecting early breast cancer,
yielding a significant improvement in breast cancer
survival.
 Mammography has been used in clinical practice since 1927
in the diagnosis of breast abnormalities.
 In the late 1950s, the pioneering work of Gershon – Cohen
and Egan demonstrated that even clinically occult cancers
of early detection of breast cancer by screening asymptotic
women. 98

99.  Since the first mammography units (xeromammography
and screen-film mammography in the 1970’s) became
available, both the equipment and the examination
procedure have changed and progressed.
 A high degree of accuracy was developed with this
technique to differentiate between Benign and
Malignant disease.
99

100. Past Present
ANALOGICAL
TECHNOLOGY
DIGITAL
TECHNOLOGY
 Screening
 Clinical mammography
 Computed radiography (CR)
 Digital direct
 Computed Aided Diagnosis
(CAD)
 Tomosynthesis - 3D
 CESM
Mammography
100

101. 101

102.  Improved detection efficiency
 A linear dynamic range
 Increased signal-to-noise ratio (SNR)
 Excellent Image Handling
 Data in Digital form
 Computer Aided Detection
 Compatibility with PACS and Telemammography
102

103. Early Detection Is Your
BEST PROTECTION
If breast cancer is found and treated early, the five-year survival rate is 98
percent.
The social prejudices and stigma associated in screening of breast is to be
sensitized.
The success of the scheme depends upon the involvement of radiologists
and lab attendants who have to handle with delicate and humane.
Another success of the scheme rests upon instead of bringing the people
to lab, the lab itself has to go in search of the patient. For which a handy
and portable mammogram has to developed for instant and hassle free
Service. 103

104. Portable Mammography
 GE unveiled an impressive portable
mammography concept as part of a
portfolio of integrated technologies aimed
at combating cancer.
 The SenoCase is mobile mammography
system which can be folded and easily
stored in a car boot.
104

105.  According to GE, such portability could remove geographical barriers to
regular breast screening for many women on a global scale.
 The system could also be more cost effective than conventional
mammography systems, making it more accessible to smaller practices
and clinics.
A standard field of view Cesium Iodide
detector
Similar image quality to a full-field digital
mammography system
A user-friendly interface, operable by a
single clinician
105

106. Digital Portable Mammography
model was preferred in employee
surveys.
 Employee feedback confirmed
that Women Diagnostic Center
mammograms are more convenient,
private and familiar because
employees feel more comfortable.
106

107. Digital mammography has proven to be
an essential tool in the diagnosis,
treatment and fight against breast cancer.
And studies have shown that routine
mammograms can help reduce breast
cancer mortality.
The important thing is that you make
annual mammography screening a top
priority for yourself and the women you
care about.
107

108. As defined at the beginning of this chapter,
angiography refers to radiologic imaging of blood
vessels after injection of a contrast medium.
To visualize these low-contrast structures, contrast
media is injected by a catheter that is placed in the vessel
of interest.
Positive contrast media are more commonly used, but
there are instances when use of negative contrast media
is indicated. Highly specialized imaging equipment is
required for these procedures.

109. 109

111.  Fluoroscopy is a technique in which a
continuous beam of x-rays is used to produce
moving images.
 It is used to show movement in the digestive
system (which may require ingestion of a
high-contrast liquid such as barium) and the
circulatory system (angiograms).

112. 112
 X-ray transmitted trough patient
 The photographic plate replaced by fluorescent screen
 Screen fluoresces under irradiation and gives a live image
 Older systems— direct viewing of screen
 Screen part of an Image Intensifier system
 Coupled to a television camera
 Radiologist can watch the images “live” on TV-monitor; images can
be recorded
 Fluoroscopy often used to observe digestive tract
 Upper GI series, Barium Swallow
 Lower GI series Barium Enema

113. 113
(Still in use in some countries)
Staff in DIRECT beam

114. 114
• AVOID USE OF DIRECT FLUOROSCOPY
• Directive 97/43Euratom Art 8.4.
 In the case of fluoroscopy, examinations without an
image intensification or equivalent techniques are
not justified and shall therefore be prohibited.
• Direct fluoroscopy will not comply with BSS
 Performance of diagnostic radiography and
fluoroscopy equipment and of nuclear medicine
equipment should be assessed on the basis of
comparison with the diagnostic reference levels

115. 115
 Remote control systems
 Not requiring the presence of
medical specialists inside the X
Ray room
 Mobile C-arms
 Mostly used in surgical theatres.

116. 116
 Interventional radiology systems
 Requires specific safety considerations.
In interventional radiology the physician
can be near the patient during the
procedure.
 Multipurpose fluoroscopy systems
 Can be used as a remote control system
or as a system to perform simple
interventional procedures

117.  Techniques which are well established in traditional engineering
applications need new hardware and software to work efficiently in the
biomedical arena. Much of our work includes fusing multiples sources of
data, or fusing data with underlying models of movement or tissue
properties to improve predictions, sometimes with the development of
novel instrumentation.
 Current applications are in cancer diagnosis and therapy, stroke
rehabilitation and orthopaedics. Recent projects have included monitoring
heat distribution and tissue changes from ultrasound images in cancer
therapy (HIFU), developing protocols and instrumentation to assess arm
movement (with immediate application in stroke rehabilitation), and
ultrasound and microwave measurements on soft tissue.
 We are pursuing methods to integrate the detection of electrical as well as
mechanical properties of tissue. 117

118. Recognising abnormal states; adaptive stimulation
 At present, stimulation is continuous and this gives poor battery usage and can cause
habituation.
 The goal is to make the next generation of stimulators adaptable to particular patients
through demand driven stimulation - altering the pattern and duration of stimulation to
the brain's own signals.
 Tremor in Parkinson's disease (PD) is clearly detectable in the beta wave brain activity (as
well of course from external instrumentation such as accelerometers), but its onset is
very rapid.
 We have developed methods using autorgressive models, coherence measures and
Hidden Markov modelling to detect the change of state associated with onset of tremor
from signals received from implanted electrodes in the subthalmic nucelus (which is a
prime target for stimulation in PD patients).
 More generic work in this area has developed HMM models to identify state transitions
between different regions to identify brain networks using MEG imaging. This work is
currently been demonstrated on resting state data but will soon be applied to tremor
patients.
118

119. MEG (Magneto encephalography) imaging and application to
chronic pain patients
 MEG is the only technology suitable for functional imaging for DBS patients as they have
metal implanted in the skull so fMRI cannot be used. MEG uses a set of very sensitive
magnetic sensors placed around the head to detect the magnetic fields associated with the
neuronal activity.
 Once the signal have been acquired, an image is formed using a technique known as beam
forming which uses them to reconstruct the sources within the brain, a technique known as
beam forming.
 The signals acquired are typically with low signal to noise ratio, non-Gaussian distribution
and correlated. Beam forming is therefore challenging. It is particularly difficult for DBS
patients because artefacts arise from the coil of wire left beneath the burr hole (through
which wires are taken to the battery.
119

120. Microwave imaging to diagnose breast cancer
 Microwaves are an attractive imaging method for finding breast
tumours as the contrast between healthy tissue and tumour is
very high. However the resolution is low.
 We are working to improve the interpretation of the data
gathered from both phantoms and clinical images using
microwave clinical imaging system developed in Bristol
University.
 A spin out company from Bristol University has one of the few
clinical systems in use worldwide, which has been used in trials
in Frenchay Hospital. This work is funded by EPSRC.
120

121. Imaging Modalities
 Imaging for medical purposes involves the services of
radiologists, radiographers, medical physicists and
biomedical engineers working together as a team for
maximum output. This ensures the production of
high quality of radiological service with consequent
improvement of health care service delivery.
121

122.  Technological advances have made human imaging possible at
scales from a single molecule to the whole body.
 By linking the anatomical data collected with emerging imaging
technologies to computer simulations, researchers now can
form truly functional images of individual patients.
 These images will allow physicians not only to see what a
patient’s organs look like but also how they are functioning
even at the smallest dimensions.
 A major challenge is how to store, analyze, distribute,
understand and use the enormous amount of data associated
with thousands of images.
122

123.  Biomedical engineering stands at the forefront of this effort
because its researchers are able to integrate the engineering
tools needed to solve the technological problems of image
analysis with the deeper knowledge of the underlying biological
mechanisms.
 Already, members of the Department of Biomedical
Engineering, in close collaboration with the Departments of
Applied Mathematics and Statistics, Computer Science,
Electrical and Computer Engineering, and Radiology, have
pioneered the use of imaging technology in computational
anatomy, neuropsychiatry, computer-integrated surgery and
cardiac procedures.
123

124.  Now, researchers are expanding their imaging efforts
into other modalities and organ systems.
 Ultimately, their work will contribute to advancing
image-guided therapy and to the early diagnosis and
treatment of a host of disorders, including heart
disease and brain dysfunction.
124

125. Included in Medical Imaging Research
 Creating new systems and methods for measuring and analyzing
imaging data in humans, developing mathematical and computational
approaches to compare data across individuals, and applying these
techniques to understand, diagnose and treat disease.
 Using novel imaging techniques to provide information on three-
dimensional structure and function at the molecular, cellular, tissue,
organ and organism level.
 Improving ways to image blood flow and cardiac motion with magnetic
resonance imaging, computed tomography, ultrasound and
fluoroscopy.
 Finding and modeling the cerebral cortex to understand both normal
and abnormal shape and the relation to genetic and environmental
disease.
 Developing bio-inspired algorithms for recognizing objects and
actions in video. 125

126. Research - Biomedical Imaging
 New developments in biomedical imaging provide a window
into complex biological phenomena.
 Imaging enables researchers to track the movements of
molecules, cells, fluids, gases, or sometimes even whole
organisms.
 Imaging techniques such as x-ray crystallography and magnetic
resonance imaging can also yield information about important
biological structures from single proteins to the human brain.
 The frontiers of biomedical imaging promise to make diagnosis
of disease more accurate and less invasive, and to improve our
understanding of disease.
126

127. Imaging research encompasses
 Imaging of protein complexes involved in synaptic communication in the
brain
 Fluorescence tagging of molecules involved in intracellular signalling
networks
 Non-invasive imaging of cancer
 Imaging of human movement using dynamic MR, motion capture systems,
and ultrasonic imaging
 Molecular and biochemical imaging with PET, SPECT, and optical imaging
 Three-dimensional medical imaging of blood flow, blood vessels, and
cardiovascular lesions
 Functional human brain mapping
 Strategies for fusing images across modalities (e.g., CT and MR)
 Ultrasonic diagnostic technology in medicine
 Computational analysis and reconstruction of complex imaging data
127