Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Mri ppt

77,168 views

Published on

Mri ppt

  1. 1. Niranjan Ultrasound India pvt.Ltd Magnetic resonance iMaging Prepared by, Anand & Shonima
  2. 2. Niranjan Ultrasound India pvt.Ltd MRI • MRI is a radiology technique • That uses magnetism, radio waves, and a computer to produce images of body structures. • MRI is based on the principles of NMR • In1997 the first MRI exam was performed on a human being. • It took 5 hours to produce one image.
  3. 3. Niranjan Ultrasound India pvt.Ltd
  4. 4. Niranjan Ultrasound India pvt.Ltd HISTORY 1924 - Pauli suggests that nuclear particles may have angular momentum (spin). 1937 – Rabi measures magnetic moment of nucleus. Coins “magnetic resonance”. 1985 – Insurance reimbursements for MRI exams NMR renamed MRI 1920 1930 1940 1950 1960 1970 1980 1990 2000 1946 – Purcell shows that matter absorbs energy at a resonant frequency. 1946 – Bloch demonstrates that nuclear precession can be measured in detector coils. 1972 – Damadian patents idea for large NMR scanner to detect malignant tissue. 1959 – Singer measures blood flow using NMR (in mice). 1973 – Lauterbur publishes method for generating images using NMR gradients. 1973 – Mansfield independently publishes gradient approach t1o9 M75R –. Ernst develops 2D-Fourier transform for MR. MRI scanners become clinically prevalent. 1990 – Ogawa and colleagues create functional images using endogenous, blood-oxygenation contrast. begin.
  5. 5. Niranjan Ultrasound India pvt.Ltd FATHER OF MRI • Magnetic resonance imaging inventor
  6. 6. Niranjan Ultrasound India pvt.Ltd NOBAL PRIZES FOR MRI • 1944: Rabi Physics (Measured magnetic moment of nucleus) • 1952: Felix Bloch and Edward Mills Purcell Physics (Basic science of NMR phenomenon) • 1991: Richard Ernst Chemistry (High-resolution pulsed FT-NMR) • 2002: Kurt Wuthrich Chemistry (3D molecular structure in solution by NMR) • 2003: Paul Lauterbur & Peter Mansfield Physiology or Medicine (MRI technology)
  7. 7. Niranjan Ultrasound India pvt.Ltd WHAT CAN BE DIAGNOSED BY AN MRI SCAN? • Most ailments of the brain, including tumours • Sport injuries • Musculoskeletal problems • Most spinal conditions/injuries • Vascular abnormalities • Female pelvic problems • Prostate problems • Some gastrointestinal tract conditions • Certain ear, nose and throat (ENT) conditions • Soft tissue and bone pathology/conditions
  8. 8. Niranjan Ultrasound India pvt.Ltd WHO CAN’T HAVE AN MRI SCAN? • A cardiac pacemaker • Certain clips in your head from brain operations • A cochlear implant • A metallic foreign body in your eye • Had surgery in the last 8 weeks • If you are pregnant
  9. 9. Niranjan Ultrasound India pvt.Ltd PRINCIPLE • MRI makes use of the magnetic properties of certain atomic nuclei. • Hydrogen nucleus (single proton) present in water molecules, and therefore in all body tissues. • The hydrogen nuclei partially aligned by a strong magnetic field in the scanner.
  10. 10. Niranjan Ultrasound India pvt.Ltd CONTI.. • The nuclei can be rotated using radio waves, and they subsequently oscillate in the magnetic field while returning to equilibrium. • Simultaneously they emit a radio signal. • This is detected using antennas (coils) • Very detailed images can be made of soft tissues.
  11. 11. Niranjan Ultrasound India pvt.Ltd Randomly arranged hydrogen atom After the strong magnetic field applied
  12. 12. Niranjan Ultrasound India pvt.Ltd
  13. 13. Niranjan Ultrasound India pvt.Ltd
  14. 14. MAIN COMPONENTS OF MRI • Scanner • Computers • Recording hardware Niranjan Ultrasound India pvt.Ltd
  15. 15. Niranjan Ultrasound India pvt.Ltd SCANNER • An MRI scanner is a large tube that contains powerful magnets. • Main components of scanner – Static magnetic field coils – Gradient coils – RF (radiofrequency) coils
  16. 16. Niranjan Ultrasound India pvt.Ltd
  17. 17. Niranjan Ultrasound India pvt.Ltd Static Magnetic Field Coils • Three methods to generate magnetic field 1. Fixed magnet 2. Resistive magnet 3. Super conducting magnet • Fixed magnets and resistive magnets are generally restricted to field strengths below 0.4t • High-resolution imaging systems use super conducting magnets. • The super-conducting magnets are large and complex • They need the coils to be soaked in liquid helium to reduce their temperature to a value close to absolute zero.
  18. 18. Niranjan Ultrasound India pvt.Ltd GRADIENT COILS • Gradient coils are used to produce deliberate variations in the main magnetic field • There are usually three sets of gradient coils, one for each direction. • The variation in the magnetic field permits localization of image slices as well as phase encoding and frequency encoding. • The set of gradient coils for the z axis are helmholtz pairs, and for the x and y axis paired saddle coils.
  19. 19. Niranjan Ultrasound India pvt.Ltd
  20. 20. Niranjan Ultrasound India pvt.Ltd RADIOFREQUENCY COIL • RF coils act as transmitter and receiver • RF coils are the "antenna" of the MRI system • That transmit the RF signal and receives the return signal. • They are simply a loop of wire either circular or rectangular • Helmholtz pair coils consist of two circular coils parallel to each other. • They are used as the z gradient coils in MRI scanners • Paired saddle coils are also used for the x and y gradient coils.
  21. 21. Niranjan Ultrasound India pvt.Ltd ADVANTAGES OF MRI • No ionizing radiation • Variable thickness in any plane • Better contrast resolution • Many details without iv contrast
  22. 22. Niranjan Ultrasound India pvt.Ltd DISADVANTAGES OF MRI • Very expensive • Dangerous for patients with metallic devices placed within the body • Difficult to be performed on claustrophobic patients • Movement during scanning may cause blurry images • RF transmitters can cause severe burns if mishandled
  23. 23. Niranjan Ultrasound India pvt.Ltd SHAPES OF MRI MACHINE
  24. 24. Niranjan Ultrasound India pvt.Ltd CLOSED MRI
  25. 25. Niranjan Ultrasound India pvt.Ltd OPEN MRI
  26. 26. Niranjan Ultrasound India pvt.Ltd UPRIGHT MRI
  27. 27. Niranjan Ultrasound India pvt.Ltd FUNCTIONAL MRI • Since the early 1990s, FMRI has come • FMRI is based on the same technology as MRI • FMRI looks at blood flow • It is a technique for measuring brain activity • It works by detecting the changes in blood oxygenation and flow that occur in response to neural activity
  28. 28. Niranjan Ultrasound India pvt.Ltd DIFFERENCE BETWEEN MRI AND FMRI MRI • Views anatomical structure • Focuses on protons in hydrogen nuclei • High spatial resolution • Utilized for experimental purposes FMRI • Views metabolic function • Calculates oxygen levels • Long-distance resolution • Utilized for diagnostic purposes
  29. 29. Niranjan Ultrasound India pvt.Ltd MRI scan FMRI scan
  30. 30. Niranjan Ultrasound India pvt.Ltd
  31. 31. Niranjan Ultrasound India pvt.Ltd MANUFACTURERS OF MRI
  32. 32. Niranjan Ultrasound India pvt.Ltd
  33. 33. Niranjan Ultrasound India pvt.Ltd
  34. 34. Niranjan Ultrasound India pvt.Ltd
  35. 35. Niranjan Ultrasound India pvt.Ltd
  36. 36. Niranjan Ultrasound India pvt.Ltd
  37. 37. Niranjan Ultrasound India pvt.Ltd MARKET
  38. 38. Niranjan Ultrasound India pvt.Ltd
  39. 39. Niranjan Ultrasound India pvt.Ltd
  40. 40. Niranjan Ultrasound India pvt.Ltd
  41. 41. Niranjan Ultrasound India pvt.Ltd
  42. 42. Niranjan Ultrasound India pvt.Ltd VIDEOS • https://www.youtube.com/watch?v=AwXJNXNcLNs • https://www.youtube.com/watch?v=HQGhqE2G6zg • https://www.youtube.com/watch?v=wqrBWK8Vtwo
  43. 43. Niranjan Ultrasound India pvt.Ltd

×