The Role of Medical
Imaging Informatics
in Healthcare
Outline
• Medical
Imaging and System Integration
• Medical Imaging Informatics and CAD
• Integration of CAD to PACS Operation
• Image-assisted Treatment
• The Creation of a Continuum – Across
the Chasm from Diagnosis to Treatment
Academic Excellence
The Nobel Prize
• 1979 “For the Development of computer
assisted tomography (CAT)”
Hounsfield
Cormack
• 2003
“For the Discoveries concerning
magnetic resonance imaging (MRI)”
Paul Lauterbur
Peter Mansfield
Magnetic resonance imaging (MRI),
Magnetic resonance imaging (MRI), is a noninvasive 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.
Definition: Pathology is the study and diagnosis of
disease through examination of organs, tissues, cells
and bodily fluids
Definition: Physiology is the study of the mechanical,
physical, and biochemical functions of living
organisms.
MRI Hand animation scan
MRI vs CT
A computed tomography (CT) , originally known as computed axial tomography (CAT)
scanner uses X-rays, a type of ionizing radiation, to acquire its images, making it a good tool
for examining tissue composed of elements of a relatively higher atomic number than the
tissue surrounding them, such as bone and calcifications (calcium based) within the body
(carbon based flesh), or of structures (vessels, bowel) which have been artificially enhanced
with contrast agents containing elements of a higher atomic number than the surrounding flesh
(iodine, barium). MRI, on the other hand, uses non-ionizing radio frequency (RF) signals to
acquire its images and is best suited for non-calcified tissue.
Magnetic resonance imaging (MRI) (continued)
•The magnet is the largest and most expensive component of the scanner, and
the remainder of the scanner is built around the magnet. Just as important as the
strength of the main magnet is its precision. The straightness of flux lines within
the centre or, as it is known as, the iso-centre of the magnet, need to be almost
perfect.
•Magnetic gradients are generated by three orthogonal coils, oriented in the x, y
and z directions of the scanner. These are usually resistive electromagnets
powered by sophisticated amplifiers which permit rapid and precise adjustments
to their field strength and direction.
•In 1983 Ljunggren[9] and Tweig[10] independently introduced the k-space
formalism, a technique that proved invaluable in unifying different MR imaging
techniques. They showed that the demodulated MR signal S(t) generated by
freely precessing nuclear spins in the presence of a linear magnetic field gradient
G equals the Fourier transform of the effective spin density i.e.
MRI Animation 1
PET Positron Emission Tomography
•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.
•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).
PET Animation
Pet Animation Atoms
Computed tomography (CT), originally known as computed axial tomography (CAT
or CT scan) and body section roentgenography, is a medical imaging method
employing tomography where digital geometry processing is used to generate a
three-dimensional image of the internals of an object from a large series of twodimensional X-ray images taken around a single axis of rotation
Medical Imaging
• Body Region, Organ, Tissue, Cell, Gene
• Diseases – What you want to detect, to
see, or to diagnosis?
• Energy sources
• Detectors
• Image formation
• Display
• User Interface
• Connection to other Systems
Anatomy to Physiology
• Anatomy: Body regions, organs, blood
vessels, etc.
•Can we see smaller anatomy? How small is
small?
•Static vs. Dynamics: how fast can we detect
and record?
• Physiology: Functions, metabolism, oxygen
concentration, blood flow, etc.
How fast can we detect and record?
• Can we combine anatomy and physiology?
Can we see the dynamic?
Medical Images
• One-dimensional Signals
• Two-dimensional Images
• Three-Dimensional Images
• Four-Dimensional Images
• Five- or Higher-Dimensional ?
Rotating Tesseract
The four-dimensional equivalent of a cube.
The fourth dimension and orthogonality
A right angle is defined as one quarter of a revolution. Cartesian geometry arbitrarily
chooses orthogonal directions through space, which means that they are at right angles to
one another. The orthogonal directions of three-dimensional space are known as the
length, width and height. The fourth dimension is therefore the direction in space that is at
right angles to these three observable directions.
X-Ray
MRI Scan
MRI Scan with injected isotopes
MRI Scan with injected isotopes
One 256-Slice CT Scan
256 x 0.5 MB = 178 MB
Medical Imaging
• Body Region, Organ, Tissue, Cell
• Diseases – What you want to detect to
see, or diagnosis?
• Energy sources
• Detectors
• Image formation
• Display
• User Interface
• Connection to another Systems
Imaging Informatics
• Computer Software Technology
• Mathematical Modeling
• Patient Information & History
• PACS and other medical Image Data
• Infrastructure
– Networking
– knowledge base
– Visualization and Presentation
One Approach to Image Storage
Picture Archiving and Communication System –( PACS)
CAD (Computer Aided Diagnosis/ (Detection))
• CADx – CA Diagnosis
• Provide computer output to assist human
(radiologist) in image interpretation
• One of the major research subjects in
medical imaging and diagnostic radiology
during the past 5 years
• Being applied in clinical practice
Effect of CAD on Ambulatory Care and Emergency Physicians
•The automated assist and diagnosis software is approaching the quality of
human experts that evaluate images
•The unaided scan on left was enhanced and evaluated using the CADdiagnosis software and the picture on the right color coded the abnormality
and displayed a message.
CAD-PACS
(Computer Aided Diagnostics – Picture Archiving and
Communications System)
Integration Using
DICOM & IHE
(Data Integration and Communications)
Combined Diagnosis with
Treatment
Ultrasound-guided Endoscopy: Imagine
•Traditional endoscopy: Use fiber optic with visible light
•Ultrasound endoscopy: Small transducer at the end of
endoscopic tube
•Two possible types of images: Circumferential image of
lumen Planar image of lumen
Source: Barret’s Foundation
Ultrasound-guided Endoscopy: Example
•Ultrasound endoscopy for upper GI
tract
•Two transducers at tip of
endoscope: Low frequency: Imaging
High frequency:treatment
Source: Penn Center
Ultrasound-guided Endoscopy: Treatment
•Tumor detection with ultrasound
•Heating and killing tumor cells with high intensity focused
ultrasound (HIFU)
•Effective hyperthermia: above 70°C Mechanical result: tissue
disruption
•Focus: possible single transducer to send both imaging and
therapeutic frequencies