LECTURE 1

Introduction to Medical

Imaging Dr. Warsito

MK Pengantar Fisika Pencitraan (S2)

MK Pencitraan Diagnostik I (S1)

FMIPA Fisika, Universitas Indonesia

Kurikulum MK Pencitraan Diagnostik I

Lectures

Introduction to Medical Imaging (1X)

Principles of CT Scan (2X)

MATLAB Programming (2X)

MATLAB Visualization (2X)

CT Scan Imaging with MATLAB (4X)

Cases Study: CT Images (1X)

Grading

Practices

Final assignment (Programming, paper)

Principles of Medical Imaging

Electromagnetic spectrum

General principle of Imaging Technique

COMPUTER SCI.

Software

MATHEMATICS

Algorithms

ELECTRONICS

Hardwares

PHYSICS

Sensor technology

Related Fields

TOMO

GRAPHY

TOMOGRAPHY development requires

related fields of PHYSICS for sensor

development, ELECTRONICS for data

acquisition hardware, COMPUTER

SCIENCE for software and MATHEMATICS

for algorithm developments. All tomography

modalities use very similar hardware, software

and mathematical algorithm. However,

different application requires different sensor.

Thus, the largest division of the system

development is in the sensor part, while the

other components are easily used as

templates.

Medical Imaging Modality See inside of the body

CT Scan: Image bone structures

CT PET

Image fusion

readily localized

tumor location in

the spleen

(arrow) in this

patient with

lymphoma

(green

arrowheads

indicate normal

physiologic

activity in the

bowel and

kidney).

Hospitals need different types of tomography

imaging system to differentiate illness from

healthy tissues for diagnostic purposes.

PET: Visualize

physiological function

of patients

MRI: Image different soft tissues

Actual Vs CT-Image

Radiography—CT (High Dose)

Radiography—

CT (Low Dose)

Low-Dose Screening CT Chest

for Detection of Lung Cancer Screening CT

Chest shows lung carcinoma in the left lower lobe.

CT Scanner

State-of-the-art multislice helical CT scanners, including Florida's first 64-slice CT scanner

Exam requires less than 20 seconds

Does not require intravenous contrast injection

Radiation dose is very low, approaching that of a routine chest x-ray

CT

Angiography

Helical CT scanning

allows acquisition of

volumetric data (rather

than single slices).

Data can be post

processed for

reformation into other

planes, surface display,

and blood vessel

delineation (CT

angiography).

Classification of Medical Imaging Modalities

2D Projection Imaging

Radiography (X-Ray Photography), Mammography, Bone Scan

Tomography Imaging

CT Scan (X-Ray Tomography)

MRI (Magnetic Resonance Imaging)

PET (Positron Emission Tomography)—SPECT

Acoustic Imaging

USG—ECG

Electrical Properties Imaging

EIT (Electrical Impedance Tomography)

ECVT (Electrical Capacitance Volume Tomography): 4D brain

activity scanner, breast cancer scanner

PET

Patient with ovarian

carcinoma and

metastates to

retroperitoneum and

right iliac lymph nodes,

which resulted in right

sided kidney

obstruction.

IMAGE FUSION – PET-CT

Image fusion readily localized

tumor location in the spleen

(arrow) in this patient with

lymphoma (green

arrowheads indicate normal

physiologic activity in the

bowel and kidney).

CT PET

PET

The combined CT & PET data effectively increases

specificity and sensitivity of each exam. Lymphoma

in the axilla (green on fused CT image of the upper

chest on image below) could be easily overlooked

when evaluated by CT alone.

MRI

MRI of the Brain - Sagittal

T1 Contrast

TE = 14 ms

TR = 400 ms

T2 Contrast

TE = 100 ms

TR = 1500 ms

Proton Density

TE = 14 ms

TR = 1500 ms

MRI of the Brain - Axial

T1 Contrast

TE = 14 ms

TR = 400 ms

T2 Contrast

TE = 100 ms

TR = 1500 ms

Proton Density

TE = 14 ms

TR = 1500 ms

Brain - Sagittal Multislice T1

Brain - Axial Multislice T1

Brain Tumor

Post-Gd T1

T1 T2

USG

USG—CT—MRI

CTECH LABS EDWAR

TECHNOLOGY

CTECH LABS EDWAR TECHNOLOGY

ECVT Technology 1. Capacitive Sensor Technology

1. Sensor Design that suits a wide range of applications 2. Electromagnetic Field Computation 3. Electrical Wave Transmission

2. Data Acquisition Technology 1. Ultra-high sensitivity: capable of detecting capacitance as low as

0.01 femtoFarads 2. High-contrast ratio: up to 100, which is able to cover wide range

of materials from air, fat and low conductive material such as water.

3. High speed capability: up to 1000 volume-frames/second

3. Volumetric Image Reconstruction Software 1. World’s first real-time volumetric (4D) tomography (PCT, 2006) 2. Arbitrary shape of geometry of scanned section 3. Next Generation Computation technology based on Soft-

computing algorithm (US Patent, 2003) 4. User oriented post-processing software

CTECH LABS EDWAR TECHNOLOGY

Principle of ECVT STEP 1: Capacitance measurement

STEP 2: Reconstructing 3D permittivity distribution

E

V

V

ECVT system consists of sensor system, data acquisition system

and computer system for control, image reconstruction and display

d

VC

nE ˆ

PCT, WO 2006/102388 (Warsito et al.,2006)

US PTO 6577700 (Warsito & Fan,

2003)

CTECH LABS EDWAR TECHNOLOGY

World’s First 32CH Online 4D ECVT 2.5th Generation (2009)

32 Bit ECVT Processor

ECVT has been successfully applied to monitor activity of human brain during different stimulations. Electrical signals measured from capacitance electrodes showed significant differences when the brain is in rest and in high task. The ECVT generates real time and volumetric image of the human brain during the activity. The system helps scientists to study the human brain activity, and possibly detect abnormalities in the human brain.

Electrical signal

monitoring of human brain

during different

stimulations

Snapshot of real-time volumetric images of human brain activity during stimulations

32-electrode Brain Scanner ECVT Sensor

4D Scanner of Human Brain Activity WORLD’S FIRST CTECH LABS EDWAR TECHNOLOGY

CASE: IMMATURE TERRATOMA

MRI (Coronal Plane) MRI (Sagittal Plane) MRI (Horizontal Plane)

ECVT (3D Image)

with Immature

Terratoma

Sagittal Plane Coronal Plane Horizontal Plane

Cancer

Cair

an

Normal Brain

Activity Image

ECVT for Breast Cancer Imaging

CTECH LABS EDWAR TECHNOLOGY

ECVT for Breast Scanner

MRI 3T

Comparisons of PET-CT Image and ECVT Image of Breast Cancer

ECVT Image

PET-CT Image

Statistical Data of ECVT Image for Breast Cancer

401

106

469

0 52

No of Data: 1028 MALIGNANT BREAST CANCER (CONFIRMED BY BOTH USG/MAMMOGRAPHY AND ECVT)

BENIGN BREAST TUMOR (CONFIRMED BY BOTH USG/MAMMOGRAPHY AND ECVT)

HEALTHY BREAST (CONFIRMED BY BOTH ECVT AND THE PERSON)

MALIGNANT BREAST CANCER (CONFIRMED BY USG/ MAMMOGRAPHY BUT NOT ECVT)

MALIGNANT BREAST CANCER (CONFIRMED BY ECVT BUT NOT USG/MAMMOGRAPHY)

ECVT Image of Very Early Stage of Mass Development

ECVT Image of Early Stage of Mass Development

Benign Breast Tumor

ECVT VS GOLDEN STANDARD: MALIGNANT CANCER (/f>3 [%/mm])

30 ECVT VS GOLDEN STANDARD: BENIGN TUMOR (/f < 3 [%/mm])

28

13.15%

ECVT FOR VERY EARLY STAGE BREAST CANCER DETECTION

SENSITIVITY PET-CT >20% USG/MAMMOGRAPHY f>5mm ECVT: >0.5% f>5mm

Statistical Data of ECVT Image for Breast Cancer

No of Data: 1028

Ca Ganas yang terdeteksi oleh modalitas lain dan terdeteksi oleh ECVT (konsentrasi di atas 0.30)

Tumor Jinak yang terdeteksi oleh modalitas lain dan terdeteksi oleh ecvt (konsentrasi di bawah 0.20)

Mammae bersih yang diklarifikasi oleh ECVT dan yang bersangkutan juga tidak merasakan apa-apa

Ca yang terdeteksi oleh modalitas lain tapi tidak terdeteksi oleh ecvt

Ca/tumor/kista yang tak terdeteksi oleh modalitas lain tapi terdeteksi oleh ecvt

Histogram Data of ECVT Images of Breast Cancer

0

50

100

150

200

250

300

350

400

450

500

Ca Ganas yang terdeteksi oleh modalitas lain dan

terdeteksi oleh ECVT (konsentrasi di atas 0.30)

Tumor Jinak yang terdeteksi oleh modalitas lain dan

terdeteksi oleh ecvt (konsentrasi di bawah 0.20)

Mammae bersih yang diklarifikasi oleh ECVT dan

yang bersangkutan juga tidak merasakan apa-apa

Ca yang terdeteksi oleh modalitas lain tapi tidak

terdeteksi oleh ecvt

Ca/tumor/kista yang tak terdeteksi oleh modalitas

lain tapi terdeteksi oleh ecvt

Number of Data 1028 Breast Scanner 1028 …

Statistik Citra 4D ECVT untuk Kanker Payudara

No.

Data Jumlah mammae

1 Ca Ganas yang terdeteksi oleh modalitas lain dan terdeteksi oleh ECVT (konsentrasi di atas 0.30)

401

2 Tumor Jinak yang terdeteksi oleh modalitas lain dan terdeteksi oleh ecvt (konsentrasi di bawah 0.20)

106

3 Mammae bersih yang diklarifikasi oleh ECVT dan yang bersangkutan juga tidak merasakan apa-apa

469

4 Ca yang terdeteksi oleh modalitas lain tapi tidak terdeteksi oleh ecvt

0

5 Ca/tumor/kista yang tak terdeteksi oleh modalitas lain tapi terdeteksi oleh ecvt

52

Jumlah data yang memiliki data pencitraan dengan modalitas lain selain ECVT Breast Scanner : 514 Pasang Mammae atau 1028 mammae

Water-Calibrated (Malignancy)

Water-Calibrated (Malignancy)

Oil-Calibrated (Dead Cells)

Before After

Water-Calibrated (Malignancy Image)

Oil-Calibrated (Dead-Cells Image)

Principles of

Tomography Imaging

Principle of Tomography Modality: Interaction of energy & matter

r̂XrFS rX ˆ

tE

Incident

wave

Density function Signal to measure

r̂X̂

Image

Reconstruction

r̂XrFAY

Measured parameter

Interaction range

1oak

ErF fField intensity

distribution

Radiography

—CT (Low

Dose)

Tomography data measurement Integral boundary problem

f

gradr

rErD

tQtQ

tQtQ

mi ,r,,,r

,,r,,r

21

r t,rEn̂

V

SV

dSdVQ n̂DDdiv

ri = integration domain number

Modality Interaction What to image Resolution (mm)

CT Scan

Single Photon

Emission

Computed

Tomography (SPECT)

Positron Emission

Tomography (PET)

MRI

Ultrasound

Electrical

Photon—

electron/proton

Nuclear particle

(positron)– electron

Positron—electron

EM—proton

Pressure wave—

matter

Electrical wave—

matter

Attenuation

coefficient

Anhilation process

Anhilation process

Proton density

Acoustic

impedance

Electrical

properties

0.4

7

5

1.0

0.3-10

3-10

Tomography imaging modality

Tomography imaging

tasks

Field computation

(PDE)

System of

application

Sensor design Data Acquisition

System

Field strength

distribution data: - Projection matrix

- Sensitivity matrix

Projection data (Integral

measurement data)

Sensor

construction

Image

reconstruction

Image

Post-processing

System requirements

Resolution

Speed (temporal resolution)

Single component differentiation (multimodality)

Resolution Speed Multimodality

High frequency/energy level

Narrow bandwidth

Narrow spectrum/

monochromatic

High directivity

Highly linear (‘hard field’)

Expensive in devices

E.g.: X-Ray, Gamma-Ray

Low frequency/energy level

Wide bandwidth

Wide spectrum/

polichromatic

Low directivity

Non-linear (‘Soft field’)

E.g.: MRI, Ultrasound,

Electrical

Electronic scanning

Single modality

Short transmission time

E.g.: electrical

Example: X-ray CT

Integral measurement (projection)

dlyxfpLyx

,),(

,,

Image reconstruction

,p yxf ,M -1

correction

+

-

STEP 1

STEP 2

,p

yxf ,

O

y

x

L Projection

X-ray CT system (CT Scan)

Image reconstruction technique

Principle of image reconstruction

Projection

Convolution

Y=A.X

Image Reconstruction

Deconvolution

X=A-1.Y

X=[A+mI]-1Y

f f0

dxprf ',ˆ

Back Projection Technique