DOC-2024tgtytyyyyyyy0718-WA0068 (1).pptx

Youo

1. 1 BASIC PRINCIPLES OF usg , MRI, CT, AND PET SCAN

2. BASIC PRINCIPLES OF ULTRASOUND

3. SOUND IS A MECHANICAL, LONGITUDINAL WAVE THAT TRAVELS IN A STRAIGHT LINE AND MEASURED BY CYCLE PER SECOND BY HERTZ(HZ). AUDIBLE SOUND LIES IN THE RANGE OF 20-20,000 HZ. SOUND REQUIRES A MEDIUM THROUGH WHICH TO TRAVEL. ULTRASOUND IS A MECHANICAL, LONGITUDINAL PRESSURE WAVE WITH A FREQUENCY EXCEEDING THE UPPER LIMIT OF HUMAN HEARING, WHICH IS 20,000 HZ OR 20 KHZ. MEDICAL ULTRASOUND IS > 2MHZ,(2MHZ TO 16MHZ). (1 MHZ = 10^6 HZ).

4. BASIC ULTRASOUND PHYSICS oscillations/sec = frequency - expressed in Hertz (Hz). Amplitude Wave length &frequency

5. ULTRASOUND – How is it produced? PRODUCED BY PASSING AN ELECTRICAL CURRENT THROUGH A PIEZOELECTRICAL (MATERIAL THAT EXPANDS AND CONTRACTS WITH CURRENT) CRYSTAL.

6. ULTRASOUND PRODUCTION TRANSDUCER PRODUCES ULTRASOUND PULSES (TRANSMIT 1% OF THE TIME) THESE ELEMENTS CONVERT ELECTRICAL ENERGY INTO A MECHANICAL ULTRASOUND WAVE. REFLECTED ECHOES RETURN TO THE SCAN HEAD WHICH CONVERTS THE ULTRASOUND WAVE INTO AN ELECTRICAL SIGNAL

7. FREQUENCY VS. RESOLUTION The frequency also affects the QUALITY of the ultrasound image The HIGHER the frequency, the BETTER the resolution The LOWER the frequency, the LESS the resolution A 12 MHz transducer has very good resolution , but cannot penetrate very deep into the body A 3 MHz transducer can penetrate deep into the body, but the resolution is not as good as the 12 MHz Low Frequency 3MHz. High frequency 12 MHz.

8. IMAGE FORMATION Electrical signal produces ‘dots’ on the screen. Brightness of the dots is proportional to the strength of the returning echoes Location of the dots is determined by travel time. The velocity in tissue is assumed constant at 1540m/sec Distance = Velocity Time

9. INTERACTIONS OF ULTRASOUND WITH TISSUE . Acoustic impedance (AI) is dependent on the density of the material in which sound is propagated - the greater the impedance the denser the material. Reflections comes from the interface of different AI’s works both ways (send and receive directions)

10. ACOUSTIC IMPEDANCE(Z) Is the resistance to the propagation of sound and this depend on density and velocity of sound and measured by MegaRayls ( Z). Air = 0.0004 Z.(Low acoustic impedance). Bone = 7.8 Z.(High acoustic impedance). Adipose = 1.34 Z. Liver = 1.65 Z.

11. Interactions of Ultrasound with Tissue Reflection . Refraction. Transmission Attenuation.

12. Reflection The ultrasound reflects off tissue and returns to the transducer, the amount of reflection depends on differences in acoustic impedance . The ultrasound image is formed from reflected echoes.

13. Refraction

14. Attenuation Defined - the deeper the wave travels in the body, the weaker it becomes -3 processes: reflection, absorption, refraction Air (lung)> bone > muscle > soft tissue >blood > water. Speed of sound in Air = 330 m/s, Bone =4030 m/s, Tissues =1040m/s.

15. Machines and Transducers.

16. TERMINOLOGY. Echogenicity. Hypo-Hyper-Iso-An Echoic The circle is Hyperechoic to the surrounding tissue. The circle is Hypoechoic to the surrounding tissue.

17. The circle is Isoechoic to the surrounding tissue. The circle is An Echoic to the surrounding tissue.

18. PORTABLE USG USG MACHINES WHICH CAN BE PHYSICALLY TRANSPORTED FROM ONE ROOM TO ANOTHER EXTREMELY USEFUL IN EMERGENCY SETTINGS, FOR RAPID AND ACCURATE RESULTS WHICH AID IN RAPIDLY DECIDING THE LINE OF TREATEMENT FOR PATIENTS WHO CAN NOT BE TAKEN TO THE RADIOLOGY DEPARTEMENT BECAUSE OF SOME MORBIDITY USEFUL IN TRAUMA PATIENTS, TO RAPIDLY ASSESS BLOOD OR FLUID, BY FAST.

19. Multiple Echogenicity.

20. CT SCAN – COMPUTED TOMOGRAPHY 31

21. C T 32 CT - Computed Tomography CAT Scan - Computerized Axial Tomography

22. THE BASICS OF CT 33 CT IMAGING CHAIN SYSTEM COMPONENTS ACQUISITION METHODS IMAGE QUALITY APPLICATIONS

23. CT: The beginning 34 CT founded in 1970 by Sir Godfrey Hounsfield Electrical Engineer with EMI, LTD. first applications were in neuroradiology

24. 35 Basic CT scanner components Gantry X-Ray Tube Detector Control Console

25. 1. Ga n t r y 36 CT X-ray tube High voltage generator Detector array Data acquistion system Slip ring

26. 2. The CT X-ray Tube 37 Anode heat capacity - 3.5 MHU up to 6.5 MHU Determines maximum mAs Determines volume length Dictates generator size

27. 3. Detector Elements 38 Capture energy that has not been attenuated by the patient

28. 4. Control console SET SCAN PARAMETERS kVp , MA, SCAN TIME, RECONSTRUCTION FILTER, ETC. SET SCAN MODE DIGITAL RADIOGRAPH, AXIAL OR VOLUME HOUSES RECONSTRUCTOR REVIEW AND ARCHIVE IMAGES POST-PROCESSING 39

29. PREREQUISITES FOR PERFORMING A CT-SCAN REMOVE METAL OBJECTS RFT’S SURITY THAT CT WILL PROVIDE INFORMATION IN ADDITION TO THAT PROVIDED BY X-RAY, USG,ETC. CONTRAINDICATIONS FOR CONTRAST HISTORY OF REACTON TO CONTRAST AGENTS PREGNANCY RADIO(IODINE)THERAPY FOR THYROID DISEASE DERANGED RFT’S METFORMIN USE

30. 41 Scanning methods D igital projection AP, PA, Lat or Oblique projection Surview, Scanogram Conventional CT Axial Volumetric CT Helical or spiral CT Continuous acquisition

31. 1. Digital Projection 42 X-RAY TUBE AND DETECTOR REMAIN STATIONARY PATIENT TABLE MOVES CONTINUOUSLY WITH X-RAYS “ON” PRODUCES AN IMAGE COVERING A RANGE OF ANATOMY

32. 2. Axial CT 43 X-RAY TUBE AND DETECTOR ROTATE 360° PATIENT TABLE IS STATIONARY WITH X-RAY’S “ON” PRODUCES ONE CROSS-SECTIONAL IMAGE WHEN COMPLETE, PATIENT IS MOVED TO THE NEXT LOCATION.

33. 3. Volume CT 44 X-RAY TUBE AND DETECTOR ROTATE 360° PATIENT TABLE MOVES CONTINUOUSLY WITH X-RAY’S “ON” PRODUCES A HELIX OF IMAGE INFORMATION THIS IS RECONSTRUCTED INTO 30 TO 1000 IMAGES

34. V olum e S c anning : Pi t ch 1:1 2:1 45

35. 6/3/2014 Hareesha N G, Dept of Aero Engg, DSCE 46 Advantages of Volume CT MORE COVERAGE IN A BREATH-HOLD CHEST, VASCULAR STUDIES, TRAUMA REDUCED MISREGISTRATION OF SLICES - IMPROVED MPR, 3D AND MIP IMAGES POTENTIALLY LESS IV CONTRAST REQUIRED GAPLESS COVERAGE ARBITRARY SLICE POSITIONING

36. INDICATIONS OF NCCT Bone and joint pathologies, like complex bone  fractures  and tumors. Cancer , heart pathologies,  emphysema , or  liver  masses Internal injuries and haemorrhage , esp in Trauma Locate a tumor,  blood clot , excess fluid, or infection. To guide treatment plans and procedures, such as  biopsies , surgeries, and  radiation therapy . Comparison of CT scans help to find out if treatments are working. For example, response to  chemotherapy  or radiation Deranged RFT’s

37. COMMON INDICATIONS FOR CE-CT

38. Fundamentals of Multislice CT 6/3/2014 Hareesha N G, Dept of Aero Engg, DSCE 50 ADVANCEMENT IN CT

39. Multislice Fundamentals 6/3/2014 Hareesha N G, Dept of Aero Engg, DSCE 51 FOLLOWING ARE BETTER – (R)ESOLUTION (S)PEED (V)OLUME (P)OWER

40. 6/3/2014 Hareesha N G, Dept of Aero Engg, DSCE 52 SINGLE SLICE = DUAL SLICE = QUAD SLICE = ONE 10MM SLICE PER ROTATION TWO 5MM SLICES PER ROTATION FOUR 2.5MM SLICES PER ROTATION Multislice Effectiveness Everything is better Resolution 2x 4 x -8x Dual Quad

41. . . _ _ _ M x 8 00 6/3/2014 Hareesha N G, Dept of Aero Engg, DSCE 53 Dual Slice Dual Slice Detector Optimized for 2 Slice Acquisition

42. 6/3/2014 Hareesha N G, Dept of Aero Engg, DSCE 54 CT PRINCIPLES CT attenuation information CT image quality

43. 6/3/2014 Hareesha N G, Dept of Aero Engg, DSCE 55 Attenuation X-ray beam passes through patient Each structure attenuates X-ray beam differently – According to individual densities Radiation received by detector varies according to these densities

44. 6/3/2014 Hareesha N G, Dept of Aero Engg, DSCE 56 Density information TRANSFERRED FROM DETECTOR TO CT COMPUTER RECONSTRUCTED BY COMPUTER INTO A CROSS-SECTIONAL IMAGE DISPLAYED ON SCREEN EACH PIXEL DISPLAYED ON MONITOR HAS VARYING BRIGHTNESS THE GREATER THE ATTENUATION, THE BRIGHTER THE PIXEL THE LESS ATTENUATION, THE DARKER THE PIXEL

45. Density information 6/3/2014 Hareesha N G, Dept of Aero Engg, DSCE 57 DENSITY VALUES CORRESPOND TO A RANGE OF NUMBERS – HOUNSFIELD SCALE

46. CT image quality 6/3/2014 Hareesha N G, Dept of Aero Engg, DSCE 58 Spatial resolution Ability to resolve small objects in an image Measured in lp/cm

47. Isotropic Imaging 6/3/2014 Hareesha N G, Dept of Aero Engg, DSCE 59 True 0.5mm Isotropic imaging

48. CT image quality 6/3/2014 Hareesha N G, Dept of Aero Engg, DSCE 60 CONTRAST RESOLUTION – ABILITY TO DIFFERENTIATE SMALL DENSITY DIFFERENCES IN AN IMAGE

49. CT -Angiography 6/3/2014 Hareesha N G, Dept of Aero Engg, DSCE 61 Circle of Willis

50. MRI

51. • • 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 . • • • Niranjan Ultrasound India pvt.Ltd M agnetic Resonance Imaging

52. FATHER OF MRI • Magnetic resonance imaging inventor

53. MAIN COMPONENTS OF MRI • • • SCANNER CO M PU T ERS RECORDING HARDWARE Niranjan Ultrasound India pvt.Ltd

54. S CANNE R • AN MRI SCANNER IS A LARGE TUBE THAT CONTAINS POWERFUL MAGNETS. MAIN COMPONENTS OF SCANNER STATIC MAGNETIC FIELD COILS GRADIENT COILS RF (RADIOFREQUENCY) COILS • Niranjan Ultrasound India pvt.Ltd

55. Static Magnetic Field Coils • Three methods to generate magnetic field Fixed magnet Resistive magnet 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. • • • Niranjan Ultrasound India pvt.Ltd

56. 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. • • • Niranjan Ultrasound India pvt.Ltd

57. ADVANTAGES OF MRI NO IONIZING RADIATION VARIABLE THICKNESS IN ANY PLANE BETTER CONTRAST RESOLUTION MANY DETAILS WITHOUT IV CONTRAST BETTER VISUALISATION OF SOFT TISSUES Niranjan Ultrasound India pvt.Ltd

58. 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, AFFECTED BY RESPIRATORY AND CVS MOVEMENTS • • Niranjan Ultrasound India pvt.Ltd

59. CLOSED MRI SHAPES OF MRI MACHINE

60. OPEN MRI

61. UPRIGHT MRI

62. 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 Niranjan Ultrasound India pvt.Ltd

63. 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-d i s t ance resolution Utilized for diagnostic purposes Niranjan Ultrasound India pvt.Ltd

64. MRI scan FMRI scan

65. 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. Niranjan Ultrasound India pvt.Ltd

66. THE NUCLEI CAN BE ROTATED USING RADIO WAVES, AND THEY SUBSEQUENTLY OSCILLATE IN THE MAGNETIC FIELD WHILE RETURNING TO EQUILIBRIUM. SIMULTANEOUSLY THEY EMIT A RADIOSIGNAL, WHICH IS DETECTED USING COILS VERY DETAILED IMAGES CAN BE MADE OF SOFT TISSUES. Niranjan Ultrasound India pvt.Ltd

67. Randomly arranged hydrogen atom After the strong magnetic field applied

68. INDICATIONS OF MRI SCAN • • • • • • PATHOLOGIES OF BRAIN, INCLUDING TUMOURS SPORT INJURIES MUSCULOSKELETAL PATHOLOGIES SPINAL PATHOLOGIES /INJURIES VASCULAR ABNORMALITIES PROSTATE PATHOLOGIES BREAST IMPLANT SOME GASTROINTESTINAL TRACT CONDITIONS CERTAIN EAR, NOSE AND THROAT (ENT) CONDITIONS SOFT TISSUE AND BONE PATHOLOGIES

69. CARDIAC PACEMAKER COCHLEAR IMPLANT METALLIC FOREIGN BODY IN YOUR EYE SURGERY IN THE LAST 8 WEEKS PREGNANT FEMALES METALLIC IMPLANT IN KNEE CONTRAINDICATIONS

70. PRINCIPLES & APPLICATIONS OF PET - CT

71. PET Stands for positron emission tomography Machine that can image biological and chemical activities F o r e x : imag i n g b r ain activity when the r e is a scary event Active part of brain can’t be imaged using x-ray of only CT It can be imaged using PET

72. PET/CT Medical Imaging Technique Both systems in one Gantry Aquired image combined into a coregistered image Functional imaging by PET Anatomical imaging by CT-Scanner

73. PET/CT Combines the functional information with the anatomical detail Accurate anatomical registration

74. Principles of PET Inject a radioactive tracer bind with glucose The active part of brain absorbs it more than other inactive parts The radioactive tracer is: Fluorine-18-deoxyglucose (FDG), a radionuclide labeled glucose analogue is injected into the organ that would be imaged

75. PET tracer: FDG Fluoro d eoxy g lucose is a glucose analog. Its full chemical name is 2-fluoro-2-deoxy-D-glucose , commonly abbreviated to FDG. Radioactive fluoride atom is attached to a molecule of glucose. The FDG molecule is absorbed by various tissues just as normal glucose would be.

76. FDG CH 2 HO HO HO O OH 18 F CH 2 HO HO HO O O H OH glucose 2-deoxy-2-(F-18) fluro-D-glucose Most widely used PET tracer Glucose utilization Taken up avidly by most tumours It is absorbed by various tissues as normal glucose would be. 9 By En g . Abdulkader Helwan

77. Uptake of FDG. FDG is a glucose analog that is taken up by metabolically active cells by means of facilitated transport via glucose transporters (Glut) in the cell membrane . Kapoor V et al. Radiographics 2004;24:523-543 ©2004 by Radiological Society of North America

78. FDG Metabolism FDG FDG -6-P Radio- active Glucose 18 F-FDG Radioactive Glucose 18 F-FDG X Glucose Glucose Glucose G l uc ose - 6- Phosphate Unlike glucose, FDG is trapped

79. Annihilation Reaction THE POSITRON ANNIHILATES WITH AN ELECTRON TO RELEASE ENERGY IN THE FORM OF COINCIDENT PHOTONS : 15 Coincidence Detection

80. INTERPRETATION OF IMAGES PET PROVIDES IMAGES OF QUANTITATIVE UPTAKE OF THE RADIONUCLIDE INJECTED THAT CAN GIVE THE CONCENTRATION OF RADIOTRACER ACTIVITY IN KILOBECQUERELS PER MILLILITER . METHODS FOR ASSESSMENT OF RADIOTRACER UPTAKE – VISUAL INSPECTION STANDARDIZED UPTAKE VALUE (SUV) GLUCOSE METABOLIC RATE

81. INDICATIONS FOR PET-SCAN

82. LIMITATIONS OF PET/CT fdg is not cancer specific and will accumulate in any areas of high rates of metabolism and glycolysis . therefore, increased uptake can be expected in all sites of hyperactivity at the time of FDG administration ( e.g , muscles and nervous system tissues); at sites of active inflammation or infection

83. The distribution of FDG within a normal individual (MIP).

84. Physiologic FDG uptake

85. ASSESSMENT OF TREATMENT RESPONSE Pretherapy and post therapy studies showing a complete metabolic response to therapy.

86. THANK YOU