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ULTRASOUND IN MEDICAL DIAGNOSTICS

ULTRASOUND IN MEDICAL DIAGNOSTICS. Prof. Ivo Hrazdira, MD., DSc. WHAT IS ULTRASOUND?. Acoustic vibrations of frequencies higher than 20 kHz, non audible by human ear

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ULTRASOUND IN MEDICAL DIAGNOSTICS

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  1. ULTRASOUND IN MEDICAL DIAGNOSTICS Prof. Ivo Hrazdira, MD., DSc.

  2. WHAT IS ULTRASOUND? • Acoustic vibrations of frequencies higher than 20 kHz, non audible by human ear • According to the type of interaction with cells and tissues: - ACTIVE ULTRASOUND – high intensity(applications in physical therapy and surgery) - PASSIVE ULTRASOUND – low intensity(applications in medical diagnostics)

  3. ACOUSTIC PARAMETERS • Source: - FREQUENCY - INTENSITY • Medium: - SPEED OF PROPAGATION - ACOUSTIC IMPEDANCE - ATTENUATION: - absorption . - scattering

  4. DIAGNOSTIC ULTRASOUND • PHYSICAL PRINCIPLE ULTRASONIC WAVES PASSING THROUGH THE BODY ARE PARTIALLY REFLECTED ON TISSUE INTERFACES. REFLECTIONS (ECHOES) ARE RECEIVED, PROCESSED AND DISPLAYED

  5. HISTORY OF ULTRASOUND PREPARATORY PERIOD • 1842 - DOPPLER: PRINCIPLE OF FREQUENCY SHIFT • 1880 - BROTHERS CURIE: DISCOVERY OF PIEZOELECTRIC PHENOMENON • 1916 - LANGEVIN AND CHILOWSKI: CONSTRUCTION OF THE FIRST ULTRASOUND GENERATOR (SONAR) • 1929 - SOKOLOV: BASIS OF NON-DESTRUCTIVE ULTRASOUND MATERIAL TESTING

  6. HISTORY OF DIAGNOSTIC ULTRASOUND FIRST ATTEMPS • 1942 - DUSSIK: HYPERPHONOGRAPIE (TRANSMISSION METHOD) • 1949 - KEIDEL: HEART VOLUME MEASUREMENT • 1949 - UCHIDA: A-MODE ENCEPHALOGRAPHY • 1950 - WILD: TISSUE DIFFERENTIATION • 1951 - WAGAI: BILL STONE DETECTION

  7. HISTORY OF DIAGNOSTIC ULTRASOUND • 1942 - FIRST ATTEMP - UNSUCCESSFUL CLINICAL APPLICATIONS • 1950 - 1D IMAGING (A- MODE) • 1954 - ECHOCARDIOGRAPHY (M-MODE) • 1955 - 2D - IMAGE OF ABDOMEN (B - MODE) • 1958 - 2D - IMAGING IN OBSTETRICS • 1958 - 2D - IMAGING IN OPHTHALMOLOGY • 1968 - TRANSRECTAL EXAMINATION • 1968 - FIRST CONTRAST IMAGING (SALINE)

  8. HISTORY OF DIAGNOSTIC ULTRASOUND CLINICAL APPLICATIONS (CONTINUED) • 1978 - TRANSESOPHAGEAL EXAMINATION • 1990 - BROAD-BAND TRANSDUCERS • 1992 - 3D IMAGING IN OB/GYN • 1992 - TRANSPULMONARY ECHOCONTRAST AGENTS • 1996 - NATIVE HARMONIC IMAGING • 1998 – 4D (3D imaging in real time)

  9. DIAGNOSTIC DEVICE • MAIN PARTS OF A DIAGNOSTIC DEVICE • ELECTROACOUTIC TRANSDUCER • GENERATOR OF ELECTRIC IMPULSES • PROCESSING OF RECEIVED ECHOES • DISPLAY • RECORDING SYSTEM

  10. DIAGNOSTIC DEVICES

  11. TRANSDUCERS (imaging lines)

  12. TRANSDUCERS sector convex linear transvaginal/transrectal transesophageal

  13. DIAGNOSTIC ULTRASOUND • IMAGING METHODS: - A MODE (one-dimensional) - B MODE (two-dimensional, three-dimensional) • DOPPLER METHODS: - CW - PULSED - COLOUR • COMBINED METHODS (duplex, triplex)

  14. PRINCIPLE OF A- AND B- IMAGING

  15. DIAGNOSTIC FREQUENCIES • 2 - 6 MHz abdominal ultrasound, obstetrical and gynaecological exam, echocardiography, transcranial Doppler • 7.5 - 14 MHz small parts, vascular Doppler, musculoskelatal ultrasound

  16. DIAGNOSTIC FREQUENCIES • 10 - 20 MHzophthalmology, special vascular exam • 20 - 50 MHz endoluminal exam, ultrasound biomicroscopy (ophthalmology, dermatology)

  17. A- AND B- MODE IN OPHTHALMOLOGY

  18. B- MODE IN ABDOMINAL REGION

  19. B- MODE IN OBSTETRICS

  20. B- MODE IN MUSCULOSKELETAL ULTRASOUND Meniscal Tear

  21. B- AND M- MODE IN CARDIOLOGY

  22. PROGRESS IN ULTRASONOGRAPHY • IMPROVED IMAGE DISPLAY - digital technology - 3D/4D imaging IMPROVED SIGNAL DETECTION - echo-enhancing agents - harmonic imaging

  23. PROGRESS IN ULTRASONOGRAPHY • NOVEL METHODS - anisotropic imaging - perfusion imaging - elastography • NOVEL APPLICATIONS - intraoperative - intraluminal

  24. DIGITAL TECHNOLOGY • BROADBAND SCANHEADS/ BROADBAND BEAMFORMING - captures full tissue signature • EXTENDED SIGNAL PROCESSING - digitally preserves entire signal • TISSUE SPECIFIC IMAGING - improves signal/noise ratio for detection of small, low-contrast lesions

  25. DIGITAL TECHNOLOGY

  26. BROADBAND TECHNOLOGY

  27. BROADBAND TECHNOLOGY IMAGES

  28. WHAT ARE ECHOCONTRAST AGENTS? • AIR OR GAS MICROBUBBLES, FREE OR INCAPSULATED IN A POLYMER COVER • ACCORDING TO THEIR HIGHER DIFFERENCE IN ACOUSTIC IMPEDANCE, CONTRAST AGENTS ENHANCE THE ECHOGENICITY OF THE BODY SPACE IN WHICH THEY WERE INTRODUCED

  29. ECHOCONTRAST AGENTS CATEGORY OF ECHOCONTRAST AGENTS: • GAS BUBBLES INTRODUCED INTO THE ORGANISM (ECHOVIST, LEVOVIST, ALBUNEX, ECHOVIEW) • GAS BUBBLES FORMED IN THE ORGANISM (ECHOGEN)

  30. ECHOCONTRAST AGENTS • IN VASCULAR IMAGING - enhance weak signals resulting from deep vessels or slow flow (hyperaemia, ischaemia) - improve signals from malignant neovascularization • IN NON-VASCULAR IMAGING - increase the reflectivity of particular normal or pathologic tissues (targeted agents) - delineate body cavities and communications

  31. INCAPSULATED BUBBLES(scanning electronmicrograph)

  32. HARMONIC IMAGING NEW MODE OF ULTRASOUND IMAGING, IN WHICH THE FUNDAMENTAL FREQUENCY OF RETOURNING ECHOES IS SUPPRESSED AND SIGNALS OF HARMONIC FREQUENCY ARE RECEIVED, PROCESSED AND DISPLEYED

  33. FORMS OF HARMONIC IMAGING • CONTRAST HARMONIC IMAGING microbubbles of echo enhancing agents are able to resonate and emit harmonic signal • NATIVE HARMONIC IMAGING harmonic signal is produced by oscillation of tissue structures due to the non-linear propagation of ultrasound

  34. receiving 5 MHz 2.5 5 transmission 2.5 MHz PRINCIPLE OF HARMONIC IMAGING supression

  35. HARMONIC IMAGING stone FUNDAMENTAL HARMONIC

  36. 3-D IMAGING • 3-D IMAGING TECHNOLOGY ALLOWS PHYSICIANS TO VIEW PATIENT´S NORMAL AND PATHOLOGIC ANATOMY AS A VOLUME IMAGE • IT IS SUGGESTED THAT 3-D IMAGING WILL PROVIDE A CENTRAL INTEGRATING FOCUS IN ULTRASOUND DIAGNOSTICS

  37. 3-D IMAGING PHYSICAL PRINCIPLE: • THE TRANSDUCER IS MOVED DURING EXPOSURE (linear shift, swinging, rotation) • RECEIVED ECHOES ARE STORED IN THE MEMORY • THE IMAGE IN THE CHOSEN PLAIN IS RECONSTRUCTED MATHEMATICALY

  38. 3D IMAGING

  39. 3-D COLOUR DOPPLER SONOGRAPHY • REPRESENTS A COMBINATION OF 3-D AND POWER DOPPLER TECHNOLOGY: transducer elements are electronically or manually sectored during exposure • 3D CDS ALLOWS DEPICTION OF THE OVERALL VASCULARITY IN THE AREA OF INTEREST (esp. tumours)

  40. 3D COLOUR DOPPLER IMAGING

  41. ANISOTROPIC IMAGING PHYSICAL PRINCIPLE • IN ULTRASOUND TECHNOLOGY, ANISOTROPY REPRESENTS A DIRECTIONAL DEPENDENCY OF BACKSCATTERED WAVES • THIS MODALITY CAN BE USED FOR DIFFERENTIATING NORMAL ANISOTROPIC TISSUES FROM ISOTROPIC ABNORMALITIES

  42. ANISOTROPIC IMAGING AREAS OF CLINICAL APPLICATIONS • CARDIOLOGY: MYOCARDIUM EXAMINATION • NEPHROLOGY: EXAMINATION OF RENAL CORTEX • MUSCULOSKELETAL ULTRASOUND: EXAMINATIONS OF TENDONS AND CARTILAGES

  43. ELASTOGRAPHY METHOD FOR IMAGING THE ELASTIC PROPERTIES OF TISSUES • REPRESENTS AN IMAGING ANALOGY TO PHYSICAL EXAMINATION BY TOUCH • DIFFERENCES IN MECHANICAL PROPERTIES OF TISSUES CAN BE IMAGED IN 2D- OR 3D- COLOUR-SCALE MANNER

  44. ELASTOGRAPHY MODEL MIMICING CONTRAST LESION IN PROSTATE

  45. ELASTOGRAPHY(benign and malignant lesion of the breast)

  46. ENDOLUMINAL IMAGING Transversal view of oesophageal sphincter 1 mucosa, 2 submucosa, 3 circular muscle, 4 intermuscular connective tissue, 5 longitudinal muscle, 6 adventitia 2D and 3D image of advanced oesophageal cancer

  47. DOPPLER ULTRASOUND • A.Ch. Doppler (1803-1853) • DOPPLER PRINCIPLE (1842) - frequency shift due to the movement of the source or reflector • DOPPLER METHODS SERVE IN MEDICINE FOR: - DETECTION OF TISSUE MOVEMENTS - MEASUREMENT OF BLOOD FLOW VELOCITY AND DIRECTION

  48. MILESTONES OF DOPPLER ULTRASOUND • 1960 -CONTINUOUS WAVE DOPPLER (CWD) • 1974 -PULSE WAVE DOPPLER (PWD) • 1982 -TRANSCRANIAL DOPPLER (TCD) • 1986 -COLOUR FLOW MAPPING (CFM) • 1992 -CONTRAST HARMONIC IMAGING (CHI) • 1994 -POWER DOPPLER (PD) • 1996 -TISSUE DOPPLER IMAGING (TDI)

  49. DOPPLER EQUATION 1 (Doppler shift)

  50. DOPPLER EQUATION 2 (velocity)

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