Medical Image Analysis

Medical Image AnalysisMedical Image AnalysisIntroduction

Figures come from the textbook: Medical Image Analysis, by Atam P. Dhawan, IEEE Press, 2003.

ModalitiesModalities

Figures come from the textbook: Medical Image Analysis, by Atam P. Dhawan, IEEE Press, 2003.

X-ray Computed Tomography (X-ray CT)

Magnetic Resonance Imaging (MRI)

Single Photon Emission Computed Tomography (SPECT)

Positron Emission Tomography (PET)

Ultrasound

An X-ray mammogram

Figures come from the textbook: Medical Image Analysis, by Atam P. Dhawan, IEEE Press, 2003.

Figures come from the textbook: Medical Image Analysis, by Atam P. Dhawan, IEEE Press, 2003.

An X-ray CT

A PET

Figures come from the textbook: Medical Image Analysis, by Atam P. Dhawan, IEEE Press, 2003.

An MRI

Figures come from the textbook: Medical Image Analysis, by Atam P. Dhawan, IEEE Press, 2003.

Figures come from the textbook: Medical Image Analysis, by Atam P. Dhawan, IEEE Press, 2003.

Physiology and CurrentUnderstanding

Physics of Imaging

Instrumentationand Image Acquisition

Computer Processing,Analysis and Modeling

Applications andIntervention

Figure 1.1. A collaborative multidisciplinary paradigm of medical imaging research and applications.

Medical image modalities◦Energy◦Anatomical, physiological, or

functional◦External, internal, or combination

Figures come from the textbook: Medical Image Analysis, by Atam P. Dhawan, IEEE Press, 2003.

Figures come from the textbook: Medical Image Analysis, by Atam P. Dhawan, IEEE Press, 2003.

10-10

Radio Waves

TVWaves Radar

WavesMicrowaves Infrared

RaysVisibleLight

UltravioletRays

X-rays GammaRays

102 101 1 10-1 10-2 10-3 10-4 10-6 10-7 10-8

Wavelength in meters

Frequency in Hz

10-5 10-9 10-10 10-11 10-12 10-13 10-14103

106 107 109 1010 1011 1012 1014 1015 10161013 1017 1018 1019 1020 1021 1022105 108

Energy in eV

10-9 10-8 10-6 10-5 10-4 10-3 10-1 1 10110-2 102 103 104 105 106 10710-7

MRIX-ray

Imaging

Gamma-ray Imaging

CosmicRays

Figure 1.2: Different sources of imaging modality in the electromagnetic spectrum.

Figures come from the textbook: Medical Image Analysis, by Atam P. Dhawan, IEEE Press, 2003.

Source of EnergyUsed for Imaging

ExternalInternal

Combination:External andInternal

Nuclear Medicine:Single PhotonEmission Tomography(SPECT)

Nuclear Medicine:Positron EmissionTomography(PET)

Magnetic ResonanceImaging: MRI, PMRI,FMRI

Optical FluorescenceImaging

Electrical ImpedanceImaging

MedicalImaging

Modalities

X-Ray Radiographs

X-Ray Mammography

X-Ray ComputedTomography

Optical Transmissionand TransilluminationImaging

Ultrasound Imaging andTomography

From Physiology to From Physiology to Information ProcessingInformation ProcessingUnderstanding image medium

◦Tissue density, blood flow, perfusion, cardiac motion

Physics of imaging◦Transmission of X-rays, emission of

gamma rays, MR imagingImaging instrumentation

◦Collecting the data, signal-to-noise ratio, resolution

Figures come from the textbook: Medical Image Analysis, by Atam P. Dhawan, IEEE Press, 2003.

Data acquisition methods for image formation◦Active filtering, post-processing

methods◦Back-projection, iterative and Fourier

transform methodsImaging processing and analysis

◦Enhancement, transformations, features of interest

Figures come from the textbook: Medical Image Analysis, by Atam P. Dhawan, IEEE Press, 2003.

General Performance General Performance MeasuresMeasuresPositive: Object was observedNegative: Object was not

observedTrue PositiveFalse NegativeTrue NegativeFalse Positive

Figures come from the textbook: Medical Image Analysis, by Atam P. Dhawan, IEEE Press, 2003.

Figures come from the textbook: Medical Image Analysis, by Atam P. Dhawan, IEEE Press, 2003.

True Positive

True Negative

FalseNegative

FalsePositive

True Condition

Object is

present.Object is

NOT present.

Object is

observed.

Object is

NOT observed.

ObservedInformation

Figure 1.4. A conditional matrix for defining four basic performance measures as defined in the text.

Figures come from the textbook: Medical Image Analysis, by Atam P. Dhawan, IEEE Press, 2003.

TNF

TPF

b

a

c

Figure 1.5: ROC curves with curve “a” indicating better overall classification ability than the curve “b” while the curve “c” shows the random probability.

SensitivitySpecificityAccuracy

Figures come from the textbook: Medical Image Analysis, by Atam P. Dhawan, IEEE Press, 2003.

An example of feature-adaptive contrast enhancement processing as applied to a mammogram to enhance microcalcification areas◦Histogram equalization

Figures come from the textbook: Medical Image Analysis, by Atam P. Dhawan, IEEE Press, 2003.

Figures come from the textbook: Medical Image Analysis, by Atam P. Dhawan, IEEE Press, 2003.

Figure 1.6. (a) A part of the digitized breast film-mammogram with microcalcification areas. (b): Enhanced image through feature adaptive contrast enhancement algorithm. (c): Enhanced image through histogram equalization method.