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Ultrasonography - History, evolution and principles

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Ultrasonography - History, evolution and principles

  1. 1. ULTRASOUND IMAGING Applications in head and neck DR APARNA PG, DEPT OF ORAL MEDICINE AND RADIOLOGY, SDM COLLEGE OF DENTAL SCIENCES AND HOSPITAL
  2. 2. CONTENTS: • PART I: BASICS • Introduction • History and evolution of diagnostic ultrasound • USG – basic physics • Parts of an ultrasound unit • Image Acquisition Modes • Tissue characterization • Ultrasound guided Needle PART II : • Indications of USG applications in head and neck • Normal US anatomy of head and neck • Specific pathologies and Ultrasound Imaging 3
  3. 3. INTRODUCTION • Two new dimensions of clinical practice pervade our environs; non-invasive diagnosis and cost control. UItrasonography qualifies eminently in both the regards • Ultrasound has been successfully employed as an important diagnostic aid in medical field in detecting pathologies of abdomen, breast, liver, spleen, kidneys and other superficial soft tissue lesions • Ultrasound is the imaging modality of choice for the assessment of palpable masses in the head and neck. Advances in high frequency probe technology mean that near field spatial resolution is now superior to both CT and MRI 4
  4. 4. HISTORY AND EVOLUTION 5
  5. 5. ECHOLOCATION IN NATURE 6
  6. 6. “It may be possible to discover the motions of the internal parts of bodies, whether animal, vegetable, or mineral, by the sound they make; that one may discover the works performed in the several offices and shops of a man’s body, and thereby discover what instrument or engine is out of order, what works are going on at several times, and lie still at others, and the like.” ROBERT HOOKE 7
  7. 7. 8
  8. 8. • Within a month of the Titanic tragedy, British scientist L. F. Richardson (1913) filed patents to detect icebergs with underwater echo ranging. • There were no practical ways of implementing his ideas. 9
  9. 9. • The discovery of PIEZOELECTRICITY by the Curie brothers in 1880 • Also showed that the REVERSE PIEZOELECTRIC effect • Could be used to transform piezoelectric materials into resonating transducers. 10
  10. 10. • C. CHILOWSKY AND P. LANGEVIN (1915) • Practical echo ranging in water • Device that detected objects at the bottom of the sea. • Used to detect submarines • Observed schools of dead fish that floated to the water surface. 11
  11. 11. SONAR IN THE SEA 12
  12. 12.  THERAPEUTIC ULTRASOUND (1920-1940) • Researchers began to determine the conditions under which ultrasound was safe. • Applied ultrasound to therapy, surgery, and cancer treatment • Ultrasound was used to treat members of European soccer teams as a form of physical therapy, to appease arthritic pain and eczema and to sterilize vaccines 13
  13. 13. • DR. KARL DUSSIK • 1942 in Austria Dr. Karl Dussik and his brother published their through-transmission ultrasound attenuation image of the brain, which they called a ‘‘HYPERPHONOGRAM.’’  DIAGNOSTIC ULTRASOUND 14
  14. 14. • F. Firestone’s (1945) invention of the SUPERSONIC REFLECTOSCOPE • Applied the pulse-echo ranging principle to the location of defects in metals in the form of a reasonably compact instrument. • ‘‘A-mode’’ or ‘‘a-scope’’ • Rokoru Uchida in Japan 15
  15. 15. • DR. GEORGE LUDWIG (1948) • Embedded hard gallstones in canine muscles to determine the feasibility of detecting them ultrasonically. • He found the average to be • Cav : 1540m/s, which is the standard value still used today. 16
  16. 16.  Parts of a WORLD WAR II B-29 bomber gun turret into a water tank. A subject was immersed in this tank, and a transducer revolved around the subject on the turret ring gear. DR. D. HOWRY 17
  17. 17. • PROFESSOR C. H. HERTZ detected heart motions with a flaw detector and began what later was called ‘‘ECHOCARDIOGRAPHY’’ (1953) 18
  18. 18. • 1965: • VIDOSON from Siemens, the first real-time mechanical commercial scanner. • Designed by Richard Soldner 19
  19. 19. • 1983 • The HEWLETT PACKARD 70020A phased array system became a forerunner of future systems, which had wheels, modular architectures, microprocessors, programmable capabilities, and their upgradeability (HP journal, 1983) 20
  20. 20. OTHER LANDMARKS: • 1958 – Dr. Ian MacDonald incorporated ultrasound into the OB/GYN field of medicine. • 1966 – Don Baker, Dennis Watkins, and John Reid designed pulsed Doppler ultrasound technology. • 1970s –Color Doppler ultrasound instruments. • 1980s – Kazunori Baba of the University of Tokyo developed 3D ultrasound technology and captured three-dimensional images of a fetus in 1986. 21
  21. 21. 22
  22. 22. • 2000S – PRESENT – • A variety of compact, handheld devices have come onto the market in recent years. • The iPhone now has a telesonography app • NASA has developed a virtual guidance program for non- sonographers to perform ultrasounds in space. 23
  23. 23. EVEN YOUR CARS HAVE IT!!! 24
  24. 24. BOTTLE COUNTING 25
  25. 25. THE HUMAN ECHOLOCATOR 26
  26. 26. PHYSICS OF ULTRASOUND IMAGING 27
  27. 27. 28
  28. 28. “Piezen”: Greek To push 29
  29. 29. HOW THE IMAGE IS FORMED • Electric field applied to piezoelectric crystals located on transducer surface • Mechanical vibration of crystals creates sound waves • Each crystal produces an US wave • Summation of all waves forms the US beam • Wave reflects as echo that vibrates transducer • Vibrations produce electrical pulses • Scanner processes and transforms to image 30
  30. 30. FREQUENCY AND RESOLUTION • Frequency 1-18 megahertz (mHz) • Lower frequencies = less resolution but deeper penetration • E.G. kidney, liver 1-6 mHz • Higher frequencies = smaller wavelength • capable of reflecting from smaller structures • The shorter the wavelength, the better the resolution, giving a clearer image • Readily absorbed by tissue = less penetration • Higher frequency = higher resolution • E.G. Muscles, tendons 7-18 mHz 31
  31. 31. AMPLIFICATION • The echoes that return from deeper structures are not as strong as those that come from tissues nearer the surface • Amplification done by the time-gain- compensation (TGC) amplifier 32
  32. 32. ACOUSTIC SPEED OF SOUND OF TISSUES NORMALIZED TO THE SPEED OF SOUND IN BLOOD.33
  33. 33. ACOUSTICAL IMPEDANCE • Sound wave encounters material with different density, and wave is reflected back as an echo • Gas or solids – Most of the acoustic energy is reflected - impossible to see deeper • Because of the effect of air, the normal lungs cannot be examined at all by ultrasound • Imaging through an adult skull or other bones is not possible 34
  34. 34. REFLECTION Reflecting echo pattern for a given tissue or organ is often characteristic, changes in echogenecity may be correlated with pathologic change. The higher the angle of incidence (i.e., the closer it is to a right angle), the less the amount of reflected sound. REFRACTION Bending of waves as they pass from one medium to another & can cause artifacts like spatial distortion and loss of resolution. ABSORPTION Absorption of ultrasound in fluids is a result of frictional forces that oppose the motion of particles in medium. Attenuation is the result of combined effects of Absorption, Scattering & Reflection. 35
  35. 35. ECHOGENICITY – A METHOD OF DESCRIBING THE REFLECTING ECHOS Hypoechoic – Darker (less reflection) Muscles, Blood vessels Hyperechoic – Brighter (more reflection) Bone, Cartilage Anechoic – Black (No echos) Air, Fluids Isoechoic – Equal 36
  36. 36. BASIC COMPONENTS OF THE MACHINE 37
  37. 37. I. Pulser - applies high amplitude voltage to energize crystals II. Transducer – Converts electrical energy to mechanical (ultrasound) energy and vice versa III. Receiver – detects and amplifies signals TWO TYPES OF TRANSDUCERS 1.Linear - sound wave is propagated in a linear fashion parallel to the transducer surface • Ideal for MSK US 2.Curvilinear – increases field of view. • Ideal for visualization of deeper structures 38
  38. 38. A STANDARD USG UNIT 39
  39. 39. ULTRASOUND PROBE • Which probe to pick? 1. Surface area of skin/transducer 2. Frequency of emitted sound wave 40
  40. 40. CURVILINEAR PROBE Large foot print Low Frequency = Increased Depth Abdominal US Phased array PROBE smaller foot print Low Frequency = Increased Depth Abdominal US , Echocardiogram 41
  41. 41. LINEAR PROBE Flat foot print High frequency Maximum depth 10-13 cm Musculoskeletal or vessel US HOCKEY STICK PROBE High frequency Intraoperative, Musculoskeletal, Peripheral Vascular, Small Parts 42
  42. 42. FINGER TIP PROBES 43
  43. 43. 44
  44. 44. ACOUSTIC COUPLING AGENT • A fluid medium is needed to provide a link between the transducer and the surface of the patient • Water is not a good coupling agent because it evaporates rapidly owing to the heat of the body • Oil when used for a long time may dissolve the rubber or plastic shielding of the equipment • It might damage the controls of the ultrasound unit • The best acoustic coupling agent is a water soluble gel • Carbomer • EDTA • Propylene glycol • Trolamine • Distilled water 45
  45. 45. WHAT IS NEEDED IN THE ULTRASOUND SCANNING ROOM? • No radiation protection is needed • Two firm pillows should be available. • The couch should be easy to clean. • Bright sunlight should be screened or curtained off. If the room is too bright, it will not be easy to see the images on the video screen. 46
  46. 46. DIFFERENT MODES OF ULTRASOUND 47
  47. 47. A MODE [ AMPLITUDE MODE] • SIMPLEST form of US imaging • Based on pulse echo principle • Gives only one dimensional information • Used in measurement of distances • ECHO-ENCEPHALOGRAPHY AND ECHO-OPTHALMOSCOPY 48
  48. 48. B MODE [ BRIGHTNESS MODE ] • Gives two dimensional information about cross section • Cardiac chamber dimension, valvular function • If multiple B-mode images are watched in rapid sequence, they become real-time images. 49
  49. 49. 50
  50. 50. REAL-TIME • Displays motion by showing the images of the part of the body under the transducer as it is being scanned • Images change with each movement of the transducer or if any part of the body is moving (for example, a moving fetus or pulsating artery). 51
  51. 51. M MODE [MOTION MODE] • mode of displaying motion • This mode is most commonly used for cardiac ultrasound 52
  52. 52. DOPPLER ULTRASOUND  The Doppler effect  The change of the frequency of reflection by a moving surface or object is the basis of measurement.  To detect and measure the rate of movement of any fluid such as blood  To measure this movement there are two basic types of Doppler ultrasound unit :  In a continuous wave Doppler unit, the ultrasound is continuous and the unit measures high velocities accurately  In a pulsed wave Doppler unit, to measure the speed of the blood in a particular vessel 54
  53. 53. • Power mode Doppler uses a color map to show the distribution of the power or amplitude of the Doppler signal. • Color flow Doppler imaging uses a color map to display information based on the detection of frequency shifts from moving targets. • The velocities are distinguished by different colours • 55
  54. 54. • DUPLEX DOPPLER SYSTEM • A blood vessel is located by b-mode ultrasound imaging and then the blood flow is measured by doppler ultrasound. 56
  55. 55. 3D AND 4D ULTRASOUND • 2 dimensional images are acquired at slightly different angles • Integrated by high speed computing software giving a 3D image • These allow us to visualize structures as static 3 dimensional images. • 4D Ultrasound allows live streaming of these 3 dimensional images allowing us to study moving organs of body in motion 57
  56. 56. SIGNIFICANCE OF ULTRASOUND IMAGING 58
  57. 57. COMPARISION OF IMAGING MODALITIES 59
  58. 58. Advantages  Portable  No ionizing radiation  Inexpensive?  Side-side comparison  Patient friendly  Guide procedures Disadvantages • Anisotropy • “now-you-can-see-me- now- you can’t” phenomena 60
  59. 59. APPEARANCES OF DIFFERENT TISSUES 61
  60. 60. BONE Hyperechoic lines with a hypoechoic shadow • Ultrasound cannot pass through bone unless it is very thin (e.g., the skull of a neonate). 62
  61. 61. MUSCLE Hypoechoic, but separated with hyperechoic septa 63
  62. 62. FAT Hypoechoic with irregular hyperechoic lines 64
  63. 63. VEINS: Anechoic, compressible ARTERIES: Anechoic, pulsatile 65
  64. 64. TENDON : Hyperechoic & fiber- like 66
  65. 65. NERVE • Hypoechoic spots buried in hyperechoic background • Honeycomb or pepper pot appearance • Bundle of straws 67
  66. 66. LYMPH NODE • Hypoechogenic masses with regular outlines • Solitary or multiple • Nodular, oval or round • Variable in size from 1 cm upwards. • the rounder the node the more likely it is to be abnormal. 68
  67. 67. CYST  Appears as an echo-free area and  The structures behind the cyst are enhanced  There are no impedance interfaces within the liquid 69
  68. 68. CYST • If there are echoes within a cyst, these may be real or artefactual • True echoes can be due to reflection from blood clot pus or necrotic debris 70
  69. 69. 71
  70. 70. SHADOWS • Calculi and calcification result in an acoustic shadow. 72
  71. 71. ABSCESS • Wide range of appearances • Anechoic or hypoechoic spherical collection of echogenic fluid with poorly defined borders • Septae , sediment or gas may be present • Compression with transducer induces movement of pus 73
  72. 72. EXAMPLES 74
  73. 73. Hepatic cyst 75
  74. 74. Neck 76
  75. 75. Buccal mucosa 77
  76. 76. Submandibular space 78
  77. 77. Submandibular gland calculi 79
  78. 78. USG GUIDED NEEDLE 80
  79. 79. • Indication : • Biopsy of a small tumour, or aspiration of a small effusion or abscess which is difficult to localize clinically. • When the fluid or tumour is close to vital organs. • To choose the shortest and safest route for needle insertion. 81
  80. 80. 82
  81. 81. Guide indicators 83
  82. 82. CONCLUSION OF PART 1: • Evolution of ultrasound imaging has been a slow but certainly interesting process • It scores over other radiation based imaging modalities and also in terms of patient friendliness • The boundaries between different tissues help in the formation of the image • Tissue characterization can be done based on the acoustic impedance • It plays a vital role for differentiating different soft tissue pathologies and also in guiding FNAC procedures 84
  83. 83. REFERENCES: • Palmer PE. Manual Of Diagnostic Ultrasound 3rd Ed 2002 • Szabo T. Diagnostic Ultrasound Imaging : Inside Out. 2nd Ed. 2004 • Loyer M, Du Brow R. Imaging Of Superficial Soft-tissue Infections: Sonographic Findings In Cases Of Cellulitis And Abscess AJR 1996;i66:149-i52 0361-803X/96/1661- 149 • JE Brown, MP Escudier.Intra-oral Ultrasound Imaging Of A Submandibular Duct Calculus • Joshi PS, Pol J, Sudesh AS. Ultrasonography – A Diagnostic Modality For Oral And Maxillofacial Diseases. Contemp Clin Dent 2014;5:345-51 85
  84. 84. REFERENCES: • PD Correa,s Arya.Ultrasonographic Changes In Malignant Neck Nodes During Radiotherapy In Head And Neck Squamous Carcinoma. Australasian Radiology(2005) 49, 113–118 • Krithika C, Ramanathan S, Koteeswaran D, Sridhar C, Satheesh Krishna J,shiva Shankar MP. Ultrasonographic Evaluation Of Oral Submucous Fibrosis In Habitual Areca Nut Chewers. Dentomaxillofac Radiol 2013; 42: 20120319. • D.C. Howletta, F. Alyasa, K.T. Wongb, K. Lewisc, M. Williamsc, A.B. Moodyc, A.T. Ahuja.Sonographic assessment of the submandibular space. Clinical Radiology (2004) 59, 1070–1078 86
  85. 85. 87
  86. 86. DRAWBACKS • It is sometimes not possible to visualize examined • lesions completely at US because of their • location, penetrating to the deep lobe of the parotid • gland or behind the acoustic shadow of the • mandible 90

Notas del editor

  • The Dussik transcranial image, which is one of the first ultrasonic images of the body ever made. Here white represents areas of signal strength and black represents complete attenuation
  • The evolution of diagnostic imaging as shown in fetal images. Fetal head black-and-white image (I. Donald, 1960). Early gray-scale negative image of fetus from the 1970s. High-resolution fetal profile from the 1980s. Surface-rendered fetal face and hand from 2002 (Goldberg and Kimmelman, 1988, reprinted with permission of AIVM.
    Courtesy of B. Goldberg, Siemens Medical Solutions, Inc., Ultrasound Group and Philips Medical
    Systems)
  • Daniel Kish was born with bilateral retinoblastoma, retinal cancer, and he had both eyes removed by the time that he was 13 months old, leaving him blind. However, he has learned to ‘see’ using echolocation, 
  • air
    becomes trapped between the transducer aiand
    the skin of the patient, it will form a barrier that
    reflects almost all the ultrasound waves,
    preventing them from penetrating the patient
  • A-mode scan: the position of the peaks shows the depth of the reflecting structure. The height indicates the strength of the echoes.
  • Collagen hyperechoic
  • The nerve is more echogenic as compared to the muscle
  • Ultrasound of a normal lymph node. Note theoval shape with the shorter transverse diameter and th echogenic hilum (arrow). Also compare the similar echogenicity of the nodal cortex to the overlying sternocleidomastoidmuscle
  • Debris within a cyst may float, forming a level which will vary as the patient's position changes
  • ICA , SCM Thyroid IJV
  • They are (from below upwards) the hyperechoic oralmucosal lining (white arrow), the hypoechoic submucosa (SM), thechogenic buccinator muscle layer (MU), the hypoechoic buccal padof fat (BFP), the superficial muscles of facial expression (SFM), thesubcutaneous tissue (SCT) and the skin (black arrow).
  • Note relations of the gland to the mylohyoid(M), hyoglossus (H) and digastric (posterior belly) (D)muscles. The facial vessels are also indicated (large white
    arrows). A hyperechoic linear structure within the gland(small white arrow) represents an intraglandular duct
  • Squamous cell carcinoma of buccal mucosa in a 55-year-old male presenting with ulceration of mucosa. Puffed cheek axial ultrasound of cheek reveals a growth predominantly involving the mucosa measuring approximately 5.36 mm in thickness resulting in disruption of mucosal white line, the mass appears distinct from submucosa (between asterix), buccinator (star) appears normal
  • Squamous cell carcinoma of buccal mucosa in a 60 yr male presenting as a ulcer along the mucosa on clinical exam, B, Tongue touch technique demonstrates a growth (star) of approximately 2.55mm involving the mucosa and submucosa. Tongue margin (arrow) appears normal. A, Normal anatomy is appreciated on right side.

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