The Role of Medical Imaging Informaticsin 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 – Acrossthe Chasm from Diagnosis to Treatment

Academic Excellence

The Nobel Prize• 1979 “For the Development of computerassisted tomography (CAT)”HounsfieldCormack

• 2003 “For the Discoveries concerningmagnetic resonance imaging (MRI)”Paul LauterburPeter Mansfield

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.

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 vs CTA 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.

MRI Hand animation scan

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 two-dimensional X-ray images taken around a single axis of rotation

Medical Imaging

• Body Region, Organ, Tissue, Cell, Gene

• Diseases – What you want to detect, tosee, or to diagnosis?

• Energy sources

• Detectors

• Image formation

• Display

• User Interface

• Connection to other Systems

Anatomy to Physiology

• Anatomy: Body regions, organs, bloodvessels, etc.•Can we see smaller anatomy? How small issmall?•Static vs. Dynamics: how fast can we detectand record?• Physiology: Functions, metabolism, oxygenconcentration, 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 ?

The fourth dimension and orthogonalityA 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.

Rotating Tesseract

The four-dimensional equivalent of a cube.

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 tosee, 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 StoragePicture 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 inmedical imaging and diagnostic radiologyduring 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 CAD-diagnosis 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 UsingDICOM & IHE

(Data Integration and Communications)

Combined Diagnosis withTreatment

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 lumenSource: Barret’s Foundation

Ultrasound-guided Endoscopy: Example

•Ultrasound endoscopy for upper GI tract

•Two transducers at tip of endoscope: Low frequency: ImagingHigh 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