SlideShare a Scribd company logo
IMAGE QUALITY
IMAGE
Contrast
Resolution
Noise
Artifacts
Distortion
INTRODUCTION
- medical images for medical necessity (anatomical/ functional
information)
- quality of medical image determined by:
* imaging method
* equipment characteristics
* imaging variables (transducers, coils, kV, gain,TE)
(* skills of operator and viewing condition)
Iterative reconstruction
* different imaging methods
* different equipment characteristics
* different equipment characteristics
* different imaging variables
* different imaging variables
80 kV 140 kV
Contrast
- difference in tissue caracteristics between specific points
low contrast medium high contrast
- result of a number of different steps during creation, image
processing and image displaying
Contrast
• three main contributors:
1. Subject contrast
- intrinsic factors
- extrinsic factors
2. Detector (film) contrast
3. Displayed contrast (image reconstruction in
digital radiograph, CT, MRI, PET,...)
Homogeneous Incident X-ray Beam
Patient
Detector
Profile of X-ray beam
emerging from patient
prior to reaching
detector
C= A-B/A
A>B; C is 0,0-1,0 (1-100%)
A=N0e-mx
and B=N0e-m(x+z)
C = 1-e-mz
m attenuation coefficient
z thickness
1. Subject contrast
A=N0e-mx
and B=N0e-m(x+z)
 C = 1-e-mz
m attenuation coefficient
z thickness
if z is larger or m is larger  C is higher!
x-rays of low kV  C is higher!
1. Subject contrast
- Intrinsic factors = actual anatomical or functional changes in the
patient’s tissues, which give rise to contrast
Physical properties Physiological properties
(f.e. atomic number) (f.e. metabolism)
•
1. Subject contrast
- Extrinsic factors = optimization of image-acquisition protocol to
enhance subject contrast
Changing x-ray energy Contrast agent
1. Subject contrast
Changing TR i TE
2. Detector (film) contrast
2. Detector (film) contrast
3. Displayed contrast
- raw image information is processed into an image that is finally
meant for physician viewing
- medical images have bit depths ranging from 10, 12,14 bits
(1024, 4096 to 16384 shades of gray)
- Modern displays capable of displaying 8-bit to 10-bit (256 to 1024
shades of gray)
 display computer needs to convert the higher bit depth data
encoded on the image to the spectrum of gray scale on the monitor
lung window (W 1600/ C -600 H.U)
mediastinal window (W 350/ C 40 H.U.)
bone window (W 1600/ C 300 H.U.)
Resolution
- Spatial resolution in radiology refers to the ability of the
imaging modality to differentiate two objects
Point Spread Function, PSF
= response of an imaging system to a point source
• most basic measure of resolution properties of an imaging system
• describes the extent of blurring that is introduced by an imaging system
• two-dimensional (2D) function PSF(x,y)
• Rotationally symmetric/ asymmetric
• describes the extent of blurring that is introduced by an imaging system
Point Spread Function, PSF
= response of an imaging system to a point source
point source symmetric response of
„imaging system”
asymmetric response of
„imaging system”
Stationary Imaging System
- the PSF remains constant over the
FOV of the imaging system
Nonstationary Imaging System
- has a different PSF depending on
the location in the FOV
- assymetric system
Line Spread Function, LSF Edge Spread Function, ESF
Slit imaging in projection radiography Imaging a plane in tomographiy sytem
Image of Line
Profile of line is measured
perpendicular to the line
gaussian blur original increasing edge enhancement
Results of 2D image processing using a variety of different convolution kernels
G(x )=


H(x ') k (x-x ') dx ‘= H(x )  k(x )
LSF (x )=PSF (x, y) ⊗ LINE( y)
LSF x = 


PSF x y dy
Modulation Transfere Function, MTF
= spatial frequency response of an imaging system
• measures resolution in frequency domain
(Fourier Transformation)
• measured in line pairs per millimeter (lp/mm)
• limited by Nyquist limit
Modulation Transfere Function, MTF
= spatial frequency response of an imaging system
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
Prostorna frekvencija (ciklus/mm)
10% MTF
limiting spatial resolution
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
MTF(f)
OUTPUTINPUT
Noise
= irregular granular pattern
- degrades image information (render images non-diagnostic)
- present in all electronic systems
- originates from a number of sources
Plain film
Plain film
Decreasing radiation intensity
CT
- Noise can be decreased by increasing mAs
- Noise can be decreased by changing filters during reconstruction
MRI
- main source is the patient's body (RF emission due to thermal motion)
- Noise can be decreased:
- use the correct coil and ensure that it is well tuned
- use a large FOV
- select thick slices
Artifacts
Medical images for medical
necessity?
Department of Brain and Cognitive Sciences, MIT / Athinoula A.
Martinos Imaging Center at the McGovern Institute for Brain Research
Neuroscientist Rebecca Saxe captured an incredible image of herself holding her 2-month-old son, Percy, and it
may be the first image of its kind. She and her colleagues took the image simply because they wanted to see it, not
for any specific diagnosis or study.

More Related Content

What's hot

Chapter 6 image quality in ct
Chapter 6 image quality in ct Chapter 6 image quality in ct
Chapter 6 image quality in ct
Muntaser S.Ahmad
 
MRI Coil and Gradient power-point slide pk
MRI Coil and Gradient power-point slide pkMRI Coil and Gradient power-point slide pk
MRI Coil and Gradient power-point slide pk
Dr pradeep Kumar
 
CTDI (Computed Tomography Dose Index
CTDI (Computed Tomography Dose IndexCTDI (Computed Tomography Dose Index
CTDI (Computed Tomography Dose Index
Vivek Elangovan
 
CR, DR and recent advances
CR, DR and recent advancesCR, DR and recent advances
CR, DR and recent advances
Vishal Sankpal
 
CT Image reconstruction
CT Image reconstructionCT Image reconstruction
CT Image reconstruction
Santosh Ojha
 
Viewing and recording the fluoroscopic image
Viewing and recording the fluoroscopic imageViewing and recording the fluoroscopic image
Viewing and recording the fluoroscopic image
SHASHI BHUSHAN
 
Fluoroscopy for Residents in Radiology
Fluoroscopy for Residents in RadiologyFluoroscopy for Residents in Radiology
Fluoroscopy for Residents in Radiology
Girendra Shankar
 
CT ITS BASIC PHYSICS
CT ITS BASIC PHYSICSCT ITS BASIC PHYSICS
CT ITS BASIC PHYSICS
DEEPAK
 
Dose reduction technique in ct scan
Dose reduction technique in ct scanDose reduction technique in ct scan
Dose reduction technique in ct scan
Mohd Aiman Azmardi
 
Fluroscopy
Fluroscopy Fluroscopy
Fluroscopy
Rakesh Ca
 
Computed Radiography and digital radiography
Computed Radiography and  digital radiographyComputed Radiography and  digital radiography
Computed Radiography and digital radiography
Durga Singh
 
Digital Radiography
Digital RadiographyDigital Radiography
Digital Radiography
santosh neupane
 
Ct Detectors
Ct DetectorsCt Detectors
Ct Detectors
NelsonMahat
 
MRI Quality Assurance
MRI Quality AssuranceMRI Quality Assurance
MRI Quality Assurance
DrPhilippMann
 
CT numbers, window width and window level
CT numbers, window width and window levelCT numbers, window width and window level
CT numbers, window width and window level
Ganesan Yogananthem
 
Digital radiography-Avinesh Shrestha
Digital radiography-Avinesh ShresthaDigital radiography-Avinesh Shrestha
Digital radiography-Avinesh Shrestha
Avinesh Shrestha
 
Flat Panel Digital Fluoroscopy by Akash Das
Flat Panel Digital Fluoroscopy by Akash Das Flat Panel Digital Fluoroscopy by Akash Das
Flat Panel Digital Fluoroscopy by Akash Das
AkashDas169
 
Direct digital radiography(1) (1)
Direct digital radiography(1) (1)Direct digital radiography(1) (1)
Direct digital radiography(1) (1)
Tarun Kumar
 
Lec2 Ali 5.Lecture 5 - CT Scan Data Acquisition System.pptx
Lec2 Ali 5.Lecture 5 - CT Scan Data Acquisition System.pptxLec2 Ali 5.Lecture 5 - CT Scan Data Acquisition System.pptx
Lec2 Ali 5.Lecture 5 - CT Scan Data Acquisition System.pptx
Ali Ayaz
 
Dry Film Technology Swastik
Dry Film Technology  SwastikDry Film Technology  Swastik
Dry Film Technology Swastik
Bipul Poudel
 

What's hot (20)

Chapter 6 image quality in ct
Chapter 6 image quality in ct Chapter 6 image quality in ct
Chapter 6 image quality in ct
 
MRI Coil and Gradient power-point slide pk
MRI Coil and Gradient power-point slide pkMRI Coil and Gradient power-point slide pk
MRI Coil and Gradient power-point slide pk
 
CTDI (Computed Tomography Dose Index
CTDI (Computed Tomography Dose IndexCTDI (Computed Tomography Dose Index
CTDI (Computed Tomography Dose Index
 
CR, DR and recent advances
CR, DR and recent advancesCR, DR and recent advances
CR, DR and recent advances
 
CT Image reconstruction
CT Image reconstructionCT Image reconstruction
CT Image reconstruction
 
Viewing and recording the fluoroscopic image
Viewing and recording the fluoroscopic imageViewing and recording the fluoroscopic image
Viewing and recording the fluoroscopic image
 
Fluoroscopy for Residents in Radiology
Fluoroscopy for Residents in RadiologyFluoroscopy for Residents in Radiology
Fluoroscopy for Residents in Radiology
 
CT ITS BASIC PHYSICS
CT ITS BASIC PHYSICSCT ITS BASIC PHYSICS
CT ITS BASIC PHYSICS
 
Dose reduction technique in ct scan
Dose reduction technique in ct scanDose reduction technique in ct scan
Dose reduction technique in ct scan
 
Fluroscopy
Fluroscopy Fluroscopy
Fluroscopy
 
Computed Radiography and digital radiography
Computed Radiography and  digital radiographyComputed Radiography and  digital radiography
Computed Radiography and digital radiography
 
Digital Radiography
Digital RadiographyDigital Radiography
Digital Radiography
 
Ct Detectors
Ct DetectorsCt Detectors
Ct Detectors
 
MRI Quality Assurance
MRI Quality AssuranceMRI Quality Assurance
MRI Quality Assurance
 
CT numbers, window width and window level
CT numbers, window width and window levelCT numbers, window width and window level
CT numbers, window width and window level
 
Digital radiography-Avinesh Shrestha
Digital radiography-Avinesh ShresthaDigital radiography-Avinesh Shrestha
Digital radiography-Avinesh Shrestha
 
Flat Panel Digital Fluoroscopy by Akash Das
Flat Panel Digital Fluoroscopy by Akash Das Flat Panel Digital Fluoroscopy by Akash Das
Flat Panel Digital Fluoroscopy by Akash Das
 
Direct digital radiography(1) (1)
Direct digital radiography(1) (1)Direct digital radiography(1) (1)
Direct digital radiography(1) (1)
 
Lec2 Ali 5.Lecture 5 - CT Scan Data Acquisition System.pptx
Lec2 Ali 5.Lecture 5 - CT Scan Data Acquisition System.pptxLec2 Ali 5.Lecture 5 - CT Scan Data Acquisition System.pptx
Lec2 Ali 5.Lecture 5 - CT Scan Data Acquisition System.pptx
 
Dry Film Technology Swastik
Dry Film Technology  SwastikDry Film Technology  Swastik
Dry Film Technology Swastik
 

Viewers also liked

Filtering Techniques to reduce Speckle Noise and Image Quality Enhancement me...
Filtering Techniques to reduce Speckle Noise and Image Quality Enhancement me...Filtering Techniques to reduce Speckle Noise and Image Quality Enhancement me...
Filtering Techniques to reduce Speckle Noise and Image Quality Enhancement me...
IOSR Journals
 
Computed radiography &digital radiography
Computed radiography &digital radiographyComputed radiography &digital radiography
Computed radiography &digital radiography
Rad Tech
 
Image quality
Image qualityImage quality
Image quality
airwave12
 
Image Contrast, Noise, Resolution
Image Contrast, Noise, ResolutionImage Contrast, Noise, Resolution
Image Contrast, Noise, Resolution
Miami Cancer Institute
 
Physics of Multidetector CT Scan
Physics of Multidetector CT ScanPhysics of Multidetector CT Scan
Physics of Multidetector CT Scan
Dr Varun Bansal
 
Image quality, digital technology and radiation protection
Image quality, digital technology and radiation protectionImage quality, digital technology and radiation protection
Image quality, digital technology and radiation protection
Rad Tech
 

Viewers also liked (6)

Filtering Techniques to reduce Speckle Noise and Image Quality Enhancement me...
Filtering Techniques to reduce Speckle Noise and Image Quality Enhancement me...Filtering Techniques to reduce Speckle Noise and Image Quality Enhancement me...
Filtering Techniques to reduce Speckle Noise and Image Quality Enhancement me...
 
Computed radiography &digital radiography
Computed radiography &digital radiographyComputed radiography &digital radiography
Computed radiography &digital radiography
 
Image quality
Image qualityImage quality
Image quality
 
Image Contrast, Noise, Resolution
Image Contrast, Noise, ResolutionImage Contrast, Noise, Resolution
Image Contrast, Noise, Resolution
 
Physics of Multidetector CT Scan
Physics of Multidetector CT ScanPhysics of Multidetector CT Scan
Physics of Multidetector CT Scan
 
Image quality, digital technology and radiation protection
Image quality, digital technology and radiation protectionImage quality, digital technology and radiation protection
Image quality, digital technology and radiation protection
 

Similar to Image Quality - Radiologic Imaging

Image processing 1-lectures
Image processing  1-lecturesImage processing  1-lectures
Image processing 1-lectures
Taymoor Nazmy
 
4.pptx
4.pptx4.pptx
Digital Imaging
Digital ImagingDigital Imaging
Image quality in nuclear medicine
Image quality in nuclear medicineImage quality in nuclear medicine
Image quality in nuclear medicine
Rad Tech
 
Super Resolution of Image
Super Resolution of ImageSuper Resolution of Image
Super Resolution of Image
Satheesh K
 
Chapter1.ppt
Chapter1.pptChapter1.ppt
Chapter1.ppt
HarisMasood20
 
CT PHYSICS for first year radiology residents
CT PHYSICS for first year radiology residentsCT PHYSICS for first year radiology residents
CT PHYSICS for first year radiology residents
drvanajabulkapuram
 
Introduction to computer graphics part 1
Introduction to computer graphics part 1Introduction to computer graphics part 1
Introduction to computer graphics part 1
Ankit Garg
 
Basics of ct lecture 2
Basics of ct  lecture 2Basics of ct  lecture 2
Basics of ct lecture 2
Gamal Mahdaly
 
Unit 1
Unit 1Unit 1
Unit 1
Ankit Garg
 
Computer Graphics - Introduction and CRT Devices
Computer Graphics - Introduction and CRT DevicesComputer Graphics - Introduction and CRT Devices
Computer Graphics - Introduction and CRT Devices
Hisham Al Kurdi, EAVA, DMC-D-4K, HCCA-P, HCAA-D
 
- Lecture 2.ppt
- Lecture 2.ppt- Lecture 2.ppt
- Lecture 2.ppt
Magde Gad
 
Cg Chap 02
Cg Chap 02Cg Chap 02
W6P3622650776P65
W6P3622650776P65W6P3622650776P65
W6P3622650776P65
Ricardo Ferrari
 
Digital image processing
Digital image processingDigital image processing
Digital image processing
ABIRAMI M
 
Lec3: Pre-Processing Medical Images
Lec3: Pre-Processing Medical ImagesLec3: Pre-Processing Medical Images
Lec3: Pre-Processing Medical Images
Ulaş Bağcı
 
E-Forensics
E-Forensics E-Forensics
Chapter 1 introduction (Image Processing)
Chapter 1 introduction (Image Processing)Chapter 1 introduction (Image Processing)
Chapter 1 introduction (Image Processing)
Varun Ojha
 
modulation transfer function (MTF)
modulation transfer function (MTF)modulation transfer function (MTF)
modulation transfer function (MTF)
AJAL A J
 
Image pipeline
Image pipelineImage pipeline
Image pipeline
Omer Korech
 

Similar to Image Quality - Radiologic Imaging (20)

Image processing 1-lectures
Image processing  1-lecturesImage processing  1-lectures
Image processing 1-lectures
 
4.pptx
4.pptx4.pptx
4.pptx
 
Digital Imaging
Digital ImagingDigital Imaging
Digital Imaging
 
Image quality in nuclear medicine
Image quality in nuclear medicineImage quality in nuclear medicine
Image quality in nuclear medicine
 
Super Resolution of Image
Super Resolution of ImageSuper Resolution of Image
Super Resolution of Image
 
Chapter1.ppt
Chapter1.pptChapter1.ppt
Chapter1.ppt
 
CT PHYSICS for first year radiology residents
CT PHYSICS for first year radiology residentsCT PHYSICS for first year radiology residents
CT PHYSICS for first year radiology residents
 
Introduction to computer graphics part 1
Introduction to computer graphics part 1Introduction to computer graphics part 1
Introduction to computer graphics part 1
 
Basics of ct lecture 2
Basics of ct  lecture 2Basics of ct  lecture 2
Basics of ct lecture 2
 
Unit 1
Unit 1Unit 1
Unit 1
 
Computer Graphics - Introduction and CRT Devices
Computer Graphics - Introduction and CRT DevicesComputer Graphics - Introduction and CRT Devices
Computer Graphics - Introduction and CRT Devices
 
- Lecture 2.ppt
- Lecture 2.ppt- Lecture 2.ppt
- Lecture 2.ppt
 
Cg Chap 02
Cg Chap 02Cg Chap 02
Cg Chap 02
 
W6P3622650776P65
W6P3622650776P65W6P3622650776P65
W6P3622650776P65
 
Digital image processing
Digital image processingDigital image processing
Digital image processing
 
Lec3: Pre-Processing Medical Images
Lec3: Pre-Processing Medical ImagesLec3: Pre-Processing Medical Images
Lec3: Pre-Processing Medical Images
 
E-Forensics
E-Forensics E-Forensics
E-Forensics
 
Chapter 1 introduction (Image Processing)
Chapter 1 introduction (Image Processing)Chapter 1 introduction (Image Processing)
Chapter 1 introduction (Image Processing)
 
modulation transfer function (MTF)
modulation transfer function (MTF)modulation transfer function (MTF)
modulation transfer function (MTF)
 
Image pipeline
Image pipelineImage pipeline
Image pipeline
 

Recently uploaded

Post-Menstrual Smell- When to Suspect Vaginitis.pptx
Post-Menstrual Smell- When to Suspect Vaginitis.pptxPost-Menstrual Smell- When to Suspect Vaginitis.pptx
Post-Menstrual Smell- When to Suspect Vaginitis.pptx
FFragrant
 
Acute Gout Care & Urate Lowering Therapy .pdf
Acute Gout Care & Urate Lowering Therapy .pdfAcute Gout Care & Urate Lowering Therapy .pdf
Acute Gout Care & Urate Lowering Therapy .pdf
Jim Jacob Roy
 
Top Travel Vaccinations in Manchester
Top Travel Vaccinations in ManchesterTop Travel Vaccinations in Manchester
Top Travel Vaccinations in Manchester
NX Healthcare
 
Breast cancer: Post menopausal endocrine therapy
Breast cancer: Post menopausal endocrine therapyBreast cancer: Post menopausal endocrine therapy
Breast cancer: Post menopausal endocrine therapy
Dr. Sumit KUMAR
 
Nano-gold for Cancer Therapy chemistry investigatory project
Nano-gold for Cancer Therapy chemistry investigatory projectNano-gold for Cancer Therapy chemistry investigatory project
Nano-gold for Cancer Therapy chemistry investigatory project
SIVAVINAYAKPK
 
The Nervous and Chemical Regulation of Respiration
The Nervous and Chemical Regulation of RespirationThe Nervous and Chemical Regulation of Respiration
The Nervous and Chemical Regulation of Respiration
MedicoseAcademics
 
Tele Optometry (kunj'sppt) / Basics of tele optometry.
Tele Optometry (kunj'sppt) / Basics of tele optometry.Tele Optometry (kunj'sppt) / Basics of tele optometry.
Tele Optometry (kunj'sppt) / Basics of tele optometry.
Kunj Vihari
 
pharmacology for dummies free pdf download.pdf
pharmacology for dummies free pdf download.pdfpharmacology for dummies free pdf download.pdf
pharmacology for dummies free pdf download.pdf
KerlynIgnacio
 
Cervical Disc Arthroplasty ORSI 2024.pptx
Cervical Disc Arthroplasty ORSI 2024.pptxCervical Disc Arthroplasty ORSI 2024.pptx
Cervical Disc Arthroplasty ORSI 2024.pptx
LEFLOT Jean-Louis
 
NARCOTICS- POLICY AND PROCEDURES FOR ITS USE
NARCOTICS- POLICY AND PROCEDURES FOR ITS USENARCOTICS- POLICY AND PROCEDURES FOR ITS USE
NARCOTICS- POLICY AND PROCEDURES FOR ITS USE
Dr. Ahana Haroon
 
How to choose the best dermatologists in Indore.
How to choose the best dermatologists in Indore.How to choose the best dermatologists in Indore.
How to choose the best dermatologists in Indore.
Gokuldas Hospital
 
K CỔ TỬ CUNG.pdf tự ghi chép, chữ hơi xấu
K CỔ TỬ CUNG.pdf tự ghi chép, chữ hơi xấuK CỔ TỬ CUNG.pdf tự ghi chép, chữ hơi xấu
K CỔ TỬ CUNG.pdf tự ghi chép, chữ hơi xấu
HongBiThi1
 
Test bank for karp s cell and molecular biology 9th edition by gerald karp.pdf
Test bank for karp s cell and molecular biology 9th edition by gerald karp.pdfTest bank for karp s cell and molecular biology 9th edition by gerald karp.pdf
Test bank for karp s cell and molecular biology 9th edition by gerald karp.pdf
rightmanforbloodline
 
Skin Diseases That Happen During Summer.
 Skin Diseases That Happen During Summer. Skin Diseases That Happen During Summer.
Skin Diseases That Happen During Summer.
Gokuldas Hospital
 
Ageing, the Elderly, Gerontology and Public Health
Ageing, the Elderly, Gerontology and Public HealthAgeing, the Elderly, Gerontology and Public Health
Ageing, the Elderly, Gerontology and Public Health
phuakl
 
Cell Therapy Expansion and Challenges in Autoimmune Disease
Cell Therapy Expansion and Challenges in Autoimmune DiseaseCell Therapy Expansion and Challenges in Autoimmune Disease
Cell Therapy Expansion and Challenges in Autoimmune Disease
Health Advances
 
Lecture 6 -- Memory 2015.pptlearning occurs when a stimulus (unconditioned st...
Lecture 6 -- Memory 2015.pptlearning occurs when a stimulus (unconditioned st...Lecture 6 -- Memory 2015.pptlearning occurs when a stimulus (unconditioned st...
Lecture 6 -- Memory 2015.pptlearning occurs when a stimulus (unconditioned st...
AyushGadhvi1
 
vonoprazan A novel drug for GERD presentation
vonoprazan A novel drug for GERD presentationvonoprazan A novel drug for GERD presentation
vonoprazan A novel drug for GERD presentation
Dr.pavithra Anandan
 
LOW BIRTH WEIGHT. PRETERM BABIES OR SMALL FOR DATES BABIES
LOW BIRTH WEIGHT. PRETERM BABIES OR SMALL FOR DATES BABIESLOW BIRTH WEIGHT. PRETERM BABIES OR SMALL FOR DATES BABIES
LOW BIRTH WEIGHT. PRETERM BABIES OR SMALL FOR DATES BABIES
ShraddhaTamshettiwar
 
Recent advances on Cervical cancer .pptx
Recent advances on Cervical cancer .pptxRecent advances on Cervical cancer .pptx
Recent advances on Cervical cancer .pptx
DrGirishJHoogar
 

Recently uploaded (20)

Post-Menstrual Smell- When to Suspect Vaginitis.pptx
Post-Menstrual Smell- When to Suspect Vaginitis.pptxPost-Menstrual Smell- When to Suspect Vaginitis.pptx
Post-Menstrual Smell- When to Suspect Vaginitis.pptx
 
Acute Gout Care & Urate Lowering Therapy .pdf
Acute Gout Care & Urate Lowering Therapy .pdfAcute Gout Care & Urate Lowering Therapy .pdf
Acute Gout Care & Urate Lowering Therapy .pdf
 
Top Travel Vaccinations in Manchester
Top Travel Vaccinations in ManchesterTop Travel Vaccinations in Manchester
Top Travel Vaccinations in Manchester
 
Breast cancer: Post menopausal endocrine therapy
Breast cancer: Post menopausal endocrine therapyBreast cancer: Post menopausal endocrine therapy
Breast cancer: Post menopausal endocrine therapy
 
Nano-gold for Cancer Therapy chemistry investigatory project
Nano-gold for Cancer Therapy chemistry investigatory projectNano-gold for Cancer Therapy chemistry investigatory project
Nano-gold for Cancer Therapy chemistry investigatory project
 
The Nervous and Chemical Regulation of Respiration
The Nervous and Chemical Regulation of RespirationThe Nervous and Chemical Regulation of Respiration
The Nervous and Chemical Regulation of Respiration
 
Tele Optometry (kunj'sppt) / Basics of tele optometry.
Tele Optometry (kunj'sppt) / Basics of tele optometry.Tele Optometry (kunj'sppt) / Basics of tele optometry.
Tele Optometry (kunj'sppt) / Basics of tele optometry.
 
pharmacology for dummies free pdf download.pdf
pharmacology for dummies free pdf download.pdfpharmacology for dummies free pdf download.pdf
pharmacology for dummies free pdf download.pdf
 
Cervical Disc Arthroplasty ORSI 2024.pptx
Cervical Disc Arthroplasty ORSI 2024.pptxCervical Disc Arthroplasty ORSI 2024.pptx
Cervical Disc Arthroplasty ORSI 2024.pptx
 
NARCOTICS- POLICY AND PROCEDURES FOR ITS USE
NARCOTICS- POLICY AND PROCEDURES FOR ITS USENARCOTICS- POLICY AND PROCEDURES FOR ITS USE
NARCOTICS- POLICY AND PROCEDURES FOR ITS USE
 
How to choose the best dermatologists in Indore.
How to choose the best dermatologists in Indore.How to choose the best dermatologists in Indore.
How to choose the best dermatologists in Indore.
 
K CỔ TỬ CUNG.pdf tự ghi chép, chữ hơi xấu
K CỔ TỬ CUNG.pdf tự ghi chép, chữ hơi xấuK CỔ TỬ CUNG.pdf tự ghi chép, chữ hơi xấu
K CỔ TỬ CUNG.pdf tự ghi chép, chữ hơi xấu
 
Test bank for karp s cell and molecular biology 9th edition by gerald karp.pdf
Test bank for karp s cell and molecular biology 9th edition by gerald karp.pdfTest bank for karp s cell and molecular biology 9th edition by gerald karp.pdf
Test bank for karp s cell and molecular biology 9th edition by gerald karp.pdf
 
Skin Diseases That Happen During Summer.
 Skin Diseases That Happen During Summer. Skin Diseases That Happen During Summer.
Skin Diseases That Happen During Summer.
 
Ageing, the Elderly, Gerontology and Public Health
Ageing, the Elderly, Gerontology and Public HealthAgeing, the Elderly, Gerontology and Public Health
Ageing, the Elderly, Gerontology and Public Health
 
Cell Therapy Expansion and Challenges in Autoimmune Disease
Cell Therapy Expansion and Challenges in Autoimmune DiseaseCell Therapy Expansion and Challenges in Autoimmune Disease
Cell Therapy Expansion and Challenges in Autoimmune Disease
 
Lecture 6 -- Memory 2015.pptlearning occurs when a stimulus (unconditioned st...
Lecture 6 -- Memory 2015.pptlearning occurs when a stimulus (unconditioned st...Lecture 6 -- Memory 2015.pptlearning occurs when a stimulus (unconditioned st...
Lecture 6 -- Memory 2015.pptlearning occurs when a stimulus (unconditioned st...
 
vonoprazan A novel drug for GERD presentation
vonoprazan A novel drug for GERD presentationvonoprazan A novel drug for GERD presentation
vonoprazan A novel drug for GERD presentation
 
LOW BIRTH WEIGHT. PRETERM BABIES OR SMALL FOR DATES BABIES
LOW BIRTH WEIGHT. PRETERM BABIES OR SMALL FOR DATES BABIESLOW BIRTH WEIGHT. PRETERM BABIES OR SMALL FOR DATES BABIES
LOW BIRTH WEIGHT. PRETERM BABIES OR SMALL FOR DATES BABIES
 
Recent advances on Cervical cancer .pptx
Recent advances on Cervical cancer .pptxRecent advances on Cervical cancer .pptx
Recent advances on Cervical cancer .pptx
 

Image Quality - Radiologic Imaging

  • 2. INTRODUCTION - medical images for medical necessity (anatomical/ functional information) - quality of medical image determined by: * imaging method * equipment characteristics * imaging variables (transducers, coils, kV, gain,TE) (* skills of operator and viewing condition)
  • 3. Iterative reconstruction * different imaging methods * different equipment characteristics
  • 4. * different equipment characteristics
  • 6. * different imaging variables 80 kV 140 kV
  • 7.
  • 8. Contrast - difference in tissue caracteristics between specific points low contrast medium high contrast - result of a number of different steps during creation, image processing and image displaying
  • 9. Contrast • three main contributors: 1. Subject contrast - intrinsic factors - extrinsic factors 2. Detector (film) contrast 3. Displayed contrast (image reconstruction in digital radiograph, CT, MRI, PET,...)
  • 10. Homogeneous Incident X-ray Beam Patient Detector Profile of X-ray beam emerging from patient prior to reaching detector C= A-B/A A>B; C is 0,0-1,0 (1-100%) A=N0e-mx and B=N0e-m(x+z) C = 1-e-mz m attenuation coefficient z thickness 1. Subject contrast
  • 11. A=N0e-mx and B=N0e-m(x+z)  C = 1-e-mz m attenuation coefficient z thickness if z is larger or m is larger  C is higher! x-rays of low kV  C is higher!
  • 12. 1. Subject contrast - Intrinsic factors = actual anatomical or functional changes in the patient’s tissues, which give rise to contrast Physical properties Physiological properties (f.e. atomic number) (f.e. metabolism) •
  • 13. 1. Subject contrast - Extrinsic factors = optimization of image-acquisition protocol to enhance subject contrast Changing x-ray energy Contrast agent
  • 15. 2. Detector (film) contrast
  • 16. 2. Detector (film) contrast
  • 17. 3. Displayed contrast - raw image information is processed into an image that is finally meant for physician viewing - medical images have bit depths ranging from 10, 12,14 bits (1024, 4096 to 16384 shades of gray) - Modern displays capable of displaying 8-bit to 10-bit (256 to 1024 shades of gray)  display computer needs to convert the higher bit depth data encoded on the image to the spectrum of gray scale on the monitor
  • 18. lung window (W 1600/ C -600 H.U)
  • 19. mediastinal window (W 350/ C 40 H.U.)
  • 20. bone window (W 1600/ C 300 H.U.)
  • 21. Resolution - Spatial resolution in radiology refers to the ability of the imaging modality to differentiate two objects
  • 22.
  • 23. Point Spread Function, PSF = response of an imaging system to a point source • most basic measure of resolution properties of an imaging system • describes the extent of blurring that is introduced by an imaging system • two-dimensional (2D) function PSF(x,y) • Rotationally symmetric/ asymmetric • describes the extent of blurring that is introduced by an imaging system
  • 24. Point Spread Function, PSF = response of an imaging system to a point source point source symmetric response of „imaging system” asymmetric response of „imaging system”
  • 25. Stationary Imaging System - the PSF remains constant over the FOV of the imaging system Nonstationary Imaging System - has a different PSF depending on the location in the FOV - assymetric system
  • 26. Line Spread Function, LSF Edge Spread Function, ESF
  • 27. Slit imaging in projection radiography Imaging a plane in tomographiy sytem Image of Line Profile of line is measured perpendicular to the line
  • 28. gaussian blur original increasing edge enhancement Results of 2D image processing using a variety of different convolution kernels
  • 29. G(x )=   H(x ') k (x-x ') dx ‘= H(x )  k(x ) LSF (x )=PSF (x, y) ⊗ LINE( y) LSF x =    PSF x y dy
  • 30. Modulation Transfere Function, MTF = spatial frequency response of an imaging system • measures resolution in frequency domain (Fourier Transformation) • measured in line pairs per millimeter (lp/mm) • limited by Nyquist limit
  • 31. Modulation Transfere Function, MTF = spatial frequency response of an imaging system 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Prostorna frekvencija (ciklus/mm) 10% MTF limiting spatial resolution 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 MTF(f) OUTPUTINPUT
  • 32.
  • 33. Noise = irregular granular pattern - degrades image information (render images non-diagnostic) - present in all electronic systems - originates from a number of sources
  • 36. CT - Noise can be decreased by increasing mAs - Noise can be decreased by changing filters during reconstruction MRI - main source is the patient's body (RF emission due to thermal motion) - Noise can be decreased: - use the correct coil and ensure that it is well tuned - use a large FOV - select thick slices
  • 38.
  • 39.
  • 40.
  • 41. Medical images for medical necessity? Department of Brain and Cognitive Sciences, MIT / Athinoula A. Martinos Imaging Center at the McGovern Institute for Brain Research Neuroscientist Rebecca Saxe captured an incredible image of herself holding her 2-month-old son, Percy, and it may be the first image of its kind. She and her colleagues took the image simply because they wanted to see it, not for any specific diagnosis or study.