2. Medical Imaging System BME 330 Lecture1

3. Part 1: Introduction Layout Definition of imaging and medical imaging
Historical overview of medical imaging
Trends of medical imaging
Factors affecting the image characteristics

4. Objectives By the end of this part, the student should:
Define and understand the general terms “image”, “imaging” and “medical imaging”
Know the brief history of medical imaging.
Define the different trends of medical imaging.
Know the importance of medical imaging.
Define the factors that affect the medical image characteristics
Understand how can the physician read the medical image and extract some information to help making a proper diagnosis and/or plan for a treatment.

5. General Definition of Imaging?
What is an image?
is a representation of the external form of a person or thing in art. Nowadays, it is the recording the feature of an object for many engineering, medical, scientific, security and/or social purposes.
How can an image be obtained?
The feature of an object could be recorded manually in arts and most widely by imaging systems either cameras or any modality.

6. General Definition of Imaging?
What is an imaging system?
It is a system that sends some sort of energy to the object of interest and then receives the energy reflected or transmitted from the object to a film sensitive to this type of energy. The received energy carries data from the object which will appear on the film as difference in intensities. It may be as simple as that or may require some transformation mechanisms get such intensity differences. Recently, there are a wide variety of imaging systems that use sophisticated technologies to get more information about the objects being imaged.

7. General Definition of Imaging?
According to the type of energy, the type of film will be.
Nowadays, there are more advanced imaging system that utilized complicated technology to convey internal as well as external features

8. Medical Imaging: Definition
Medical imaging is a process of taking an image for interior parts of the human body without surgery. This image provide information about the different properties (either anatomical and/or physiological) of the organs. The physician can use these information make proper diagnosis and plan for treatment.
Many medical imaging modalities are currently available which allow to obtain images and valuable information for almost all parts of the human body.
Examples of medical imaging modalities: x-ray imaging, CT, US imaging, MRI, …etc.

9. Medical Imaging: Definition
Main methods of obtaining medical images
Measuring the reflected radiations (eg. optical and ultrasound imaging)
Measuring the transmitted radiations (eg. x-ray imaging)
Measuring the emitted radiation (eg. magnetic resonance imaging)

10. Medical Imaging: Definition
The image modality is chosen according to the organ and properties to be investigated. The degree of hazard is also an important factor when choosing certain imaging modality
X-ray image
Abdominal CT image
US image
MRI image

11. Medical Imaging: History
Before the evolution of diagnostic equipment, doctors depend mainly on their perception (five senses: the faculties of sight, smell, hearing, taste, and touch)
The upper image is from the Common Era (Abu Bakr Al-Razy 854 – 925 CE).
The lower image is from the 19th century. Both were using their perception.
So, there was a great need to surgery to diagnose and/or treat.

12. Medical Imaging: History
X-Ray Imaging
After he accidently noticed the effect of x-ray, Rontgen started some experiments to finally reach the image of the hand of his fiancée. Within less than 2 months, the technique was common and used in many applications specially in medicine imaging.
Wilhelm Röntgen, 1895,
Image from a circus
Nothing was known about the hazards. Researches continued

13. Medical Imaging: History
X-Ray Imaging
Technological Developments lead to recent radiology
Hot cathode x-ray tubes
Rotating anodes
Intensifying screens
Image intensifiers
Contrast agents and Angiography
Computed and digital radiography CT

14. Medical Imaging: History
Radon and Radon Transform, 1924
Calculation complexity and requirements
With the advent of computer revolution, Hounsfield starts to apply Radon algorithm in 1971
In 1972, Hounsfield provides the CT prototype

15. Medical Imaging: History
CT or CAT scan
Development of CT
CT images Now

16. Medical Imaging: History
US Imaging: Sonography
Was used in military purposes and used in medicine since 1942 by the American George Ludwig
The first medical ultrasonography system was suggested in 1952

17. Medical Imaging: History
US Imaging: Sonography: Real time imaging 1953

18. Medical Imaging: History
Sonography today: 3D, 4D, color coding and elastography

19. Medical Imaging: History
Nuclear magnetic Resonance
discovered by the Nobel prize's Bloch and Purcell in They describe its physics and mathematics in 1946

20. Medical Imaging: History
Paul Lauterbur and the MRI 1973
In 1973, with the computer advancement, Lauterbur applied the theory and mathematics of NMR done by Bloch and Purcell to record the first MRI image.

21. Medical Imaging: History
High quality MR images in 1975
Ernest and utilizes the Fourier transform to reconstruct

22. Medical Imaging: History
Whole body MR image in 1977
Damadian and the first whole body MRI

23. Medical Imaging: History
Ultrafast MRI, 1977
Mansfield and the acquisition of the ultra-fast MR image in 1977

24. Medical Imaging: History
MRI today

25. Medical Imaging: History
PET & SPECT
PET and SPECT  are nuclear medicine imaging techniques which provide metabolic and functional information unlike CT and MRI.
They have been combined with CT and MRI to provide detailed anatomical and metabolic information.

26. Medical Imaging: History
Optical Imaging
The optical imaging was utilized as early as the era of the Arabian, Abulkasim ( )
The first clinical laparoscope was used in 1901.
Recently, there are many optical imaging modalities:

27. Medical Imaging: History
Optical Imaging
OCT and Fundus Camera
Photoacoustic imaging

28. Medical Imaging: Trends
Trends in medical imaging: development

29. Medical Imaging: Trends
Functional Classification of Medical Imaging
Anatomical imaging
Vascular imaging
Physiological imaging
Imaging concentration of chemical composition
Imaging for surgical aids

30. Medical Imaging: Trends
Anatomical Imaging:
Give the anatomical features of the imaged organ or part.
The doctors can compare the image to actual anatomy and decide the diagnosis

31. Medical Imaging: Trends
Anatomical Imaging:
Useful for the noninvasive detection of pathologies

32. Medical Imaging: Trends
Anatomical Imaging:
Whole body imaging to get an overall report
The spread of cancer for example

33. Medical Imaging: Trends
Anatomical Imaging:
Calculation of age of fetus

34. Medical Imaging: Trends
Anatomical Imaging:
3D reconstruction

35. Medical Imaging: Trends
Vascular Imaging:

36. Medical Imaging: Trends
Vascular Imaging:
3D reconstruction
Virtual catheterization for diagnosis

37. Medical Imaging: Trends
Vascular Imaging:
Color Doppler
Blood flow measurement: Colored Doppler
Red and blue indicates the direction of blood flow (diagnosis)

38. Medical Imaging: Trends
Physiological Imaging:
Not just an anatomical imaging
Indicates whether an organ works normally or not.
Example: 𝛾 𝑐𝑎𝑚𝑒𝑟𝑎→𝑡ℎ𝑦𝑟𝑜𝑖𝑑 𝑔𝑙𝑎𝑛𝑑 𝑎𝑐𝑡𝑖𝑣𝑖𝑡𝑦 (𝐼𝑜𝑑𝑖𝑛𝑒 𝑢𝑝𝑡𝑎𝑘𝑒)

39. Medical Imaging: Trends
Physiological Imaging:
Example: Understanding how the brain work
Take some slices, repeat along the time (sequence)
Record changes during certain activity and at rest and create a colored map

40. Medical Imaging: Trends
Imaging the concentrations of chemical composition
Noninvaisve measurement of the concentrations of different substances inside the tissue

41. Medical Imaging: Trends
Imaging the concentrations of chemical composition
More about the brain
Concentration of certain chemical composition and the relation to the activity
Choline
Choline /creatinine
Concentration spectra

42. Medical Imaging: Trends
Imaging for surgical aids
Before surgery to investigate

43. Medical Imaging: Trends
Imaging for surgical aids
During surgery to guide
MRI designed for surgical purposes
Cath. Lab

44. Medical Imaging: Trends
Imaging for surgical aids
Biopsy (somesort of surgical intervention)
US beast biopsy
US thyroid biopsy
MRI brain biopsy

45. Factors Affecting the Image Characteristics
Factors associated with the imaging system:
Image c/c vary according to the type of radiation: optical (visible, or IR), US, X-rays, NMR
Mode of detected radiation: reflection, transmission or emission
Intensity, coherency and collimation of the radiation
Sensitivity of sensors and transducers
Quality of processing elements (amplifiers, ADC, filters,..etc)
Environmental conditions:
Interference • Temperature
Properties of imaged tissue
Density • Flexibility • Chemical composition • Temperature
Magnetic resonance
Velocity of moving tissue (blood and blood components)

46. Medical Image Characteristics
Important notes
Clinician make diagnosis based on the looks of the images
Assuming that we got a number of images from same equipment, under same imaging conditions and for same patient (same tissue), then the image looks may change with the:
changes in shape, for example enlargement or shrinkage of a particular structure,
changes in image intensities within that structure compared to normal tissue and/or
the appearance of features such as lesions which are normally not seen.

47. Medical Image Characteristics
Important notes:
So, image quality is a very important factor for proper diagnosis
A full diagnosis may be based upon information from several different imaging modalities, which can be correlative or additive in terms of their information content.
Improvement in medical imaging systems is continuously done to produce high quality images:
instrumentation improvement and
image processing
Images are now saved and processed digitally