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

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Presentation on theme: "ULTRASOUND IN MEDICAL DIAGNOSTICS Prof. Ivo Hrazdira, MD., DSc."— Presentation transcript:

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

3 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)

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

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

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

7 HISTORY OF DIAGNOSTIC ULTRASOUND FIRST ATTEMPS DUSSIK: HYPERPHONOGRAPIE (TRANSMISSION METHOD) KEIDEL: HEART VOLUME MEASUREMENT UCHIDA: A-MODE ENCEPHALOGRAPHY WILD: TISSUE DIFFERENTIATION WAGAI: BILL STONE DETECTION

8 HISTORY OF DIAGNOSTIC ULTRASOUND FIRST ATTEMP - UNSUCCESSFUL CLINICAL APPLICATIONS D IMAGING (A- MODE) ECHOCARDIOGRAPHY (M-MODE) D - IMAGE OF ABDOMEN (B - MODE) D - IMAGING IN OBSTETRICS D - IMAGING IN OPHTHALMOLOGY TRANSRECTAL EXAMINATION FIRST CONTRAST IMAGING (SALINE)

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

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

11 DIAGNOSTIC DEVICES

12 TRANSDUCERS (imaging lines)

13 TRANSDUCERS sector convex linear transvaginal/transrectal transesophageal

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

15 PRINCIPLE OF A- AND B- IMAGING

16 DIAGNOSTIC FREQUENCIES MHz abdominal ultrasound, obstetrical and gynaecological exam, echocardiography, transcranial Doppler MHz small parts, vascular Doppler, musculoskelatal ultrasound

17 DIAGNOSTIC FREQUENCIES MHz ophthalmology, special vascular exam MHz endoluminal exam, ultrasound biomicroscopy (ophthalmology, dermatology)

18 A- AND B- MODE IN OPHTHALMOLOGY

19 B- MODE IN ABDOMINAL REGION

20 B- MODE IN OBSTETRICS

21 B- MODE IN MUSCULOSKELETAL ULTRASOUND Meniscal Tear

22 B- AND M- MODE IN CARDIOLOGY

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

24 PROGRESS IN ULTRASONOGRAPHY NOVEL METHODS - anisotropic imaging - perfusion imaging - elastography NOVEL APPLICATIONS - intraoperative - intraluminal

25 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

26 DIGITAL TECHNOLOGY

27 BROADBAND TECHNOLOGY

28 BROADBAND TECHNOLOGY IMAGES

29 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

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

31 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

32 INCAPSULATED BUBBLES (scanning electronmicrograph)

33 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

34 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

35 PRINCIPLE OF HARMONIC IMAGING transmission 2.5 MHz 5 MHz receiving 52.5 supression

36 HARMONIC IMAGING FUNDAMENTAL HARMONIC stone

37 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

38 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

39 3D IMAGING

40 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)

41 3D COLOUR DOPPLER IMAGING

42 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

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

44 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

45 ELASTOGRAPHY MODEL MIMICING CONTRAST LESION IN PROSTATE

46 ELASTOGRAPHY (benign and malignant lesion of the breast)

47 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

48 DOPPLER ULTRASOUND A.Ch. Doppler ( ) 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

49 MILESTONES OF DOPPLER ULTRASOUND CONTINUOUS WAVE DOPPLER (CWD) PULSE WAVE DOPPLER (PWD) TRANSCRANIAL DOPPLER (TCD) COLOUR FLOW MAPPING (CFM) CONTRAST HARMONIC IMAGING (CHI) POWER DOPPLER (PD) TISSUE DOPPLER IMAGING (TDI)

50 DOPPLER EQUATION 1 (Doppler shift)

51 DOPPLER EQUATION 2 (velocity)

52 CONVENTIONAL DOPPLER METHODS

53 FLOW DIRECTION

54 MAIN VELOCITY CURVES Low vascular impedance High vascular impedance

55 COLOUR FLOW MAPPING (right renal artery)

56 COLOUR FLOW MAPPING (common carotid artery)

57 COLOUR FLOW MAPPING

58 NEW COLOUR DOPPLER IMAGING MODALITIES POWER DOPPLER (Colour Doppler Energy, Colour Doppler Angio) TISSUE DOPPLER IMAGING (TDI) 3-D COLOUR DOPPLER SONOGRAPHY (3D CDS)

59 POWER DOPPLER NEW TECHNOLOGY OF DOPPLER SIGNAL PROCESSING, IN WHICH ITS ENERGY ISTEAD OF ITS AMPLITUDE IS RECORDED THE ENERGY IS RELATED TO THE SQUARE OF THE AMPLITUDE OF THE SIGNAL USING THIS TECHNOLOGY, EVEN WEAK SIGNALS (CORRESPONDING TO LOW FLOW RATES) CAN BE RECORDED

60 DOPPLER SIGNAL ENERGY

61 POWER DOPPLER (renal perfusion)

62 POWER DOPPLER (increased thyroid perfusion)

63 POWER DOPPLER (kinking of internal carotid artery)

64 POWER DOPPLER ADVANTAGE - detection of very low blood flow - more complete displaying of the vascular bed - absence of aliasing and only little angle dependence DISADVANTAGE - loss of directional and partial loss of velocity information

65 TISSUE DOPPLER IMAGING NEW COLOUR DOPPLER IMAGING MODALITY IN WHICH THE DOPPLER SIGNAL IS DERIVED FROM SLOW TISSUE MOVEMENTS THE SYSTEM SUPRESSES FAST VELOCITIES OF BLOOD FLOW AND RECORDS ONLY SLOW MOVEMENTS IN THE RANGE mm/s

66 CLINICAL IMPORTANCE OF TDI ASSESSMENT OF MYOCARDIUM MOVEMENTS DURING HEART CONTRACTION ASSESSMENT OF DISTENSIBILITYAND COMPLIANCE OF VESSEL WALL ASSESSMENT OF SKELETAL MUSCLES CONTRACTIBILITY AND TENDON MOVEMENTS

67 TDI - HEART Colour imaging of blood flow TDI- Colour imaging of heart movements

68 TDI - ARTERY

69 FUTURE OF ULTRASONOGRAPHY In the medical imaging world, it is hard to beat ultrasound in following terms: COST - EFFECTIVENESS RANGE OF APPLICATIONS SAFETY

70 FUTURE OF ULTRASONOGRAPHY ACCORDING TO RECENT ADVANCES IN POWER DOPPLER, 3-D IMAGING, CONTRAST AGENTS, HARMONIC IMAGING AND INTERVENTIONAL APPLICATIONS, ULTRASONOGRAPHY BECOMES THE PREFERRED DIAGNOSTIC IMAGING MODALITY OF THE 21 TH CENTURY


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