Basics of echocardiograghy


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Basics of echocardiograghy

  1. 1. BASICS OF ECHOCARDIOG RAGHY Dr Ramachandra Barik, DNB(Cardiology) NIMS,Hydearabad-500082,India.
  2. 2. First, ultrasound can be directed as a beam and focused It obeys the laws of reflection and refraction It is poorly transmitted through a gaseous medium and attenuation occurs rapidly, especially at higher frequencies. The amount of reflection, refraction, and attenuation depends on the acoustic properties of the various media through which the ultrasound beam passes.
  3. 3. Within soft tissue, velocity of sound is fairly constant at approximately 1,540 m/sec (or 1.54 m/msec, or 1.54 mm/µsec).  Wave length(in millimeters) = 1.54/f, where f is the transducer frequency (in megahertz).
  4. 4. higher frequency ultrasound has less penetration compared with lower frequency ultrasound. The loss of ultrasound as it propagates through a medium is referred to as attenuation. Attenuation has three components: absorption, scattering, and reflection. Attenuation always increases with depth and is also affected by the frequency and
  5. 5. Attenuation may be expressed as “half- value layer”or “half-power distance”which is a measure of the distance that ultrasound travels before its amplitude is decreased to one half its original value As a rule of thumb, the attenuation of ultrasound in tissue is between 0.5 and 1.0 dB/cm/MHz.
  6. 6. The velocity and direction of the ultrasound beam as it passes through a medium are a function of the acoustic impedance of that medium. Acoustic impedance (Z, measured in rayls) is simply the product of velocity (in meters per second) and physical density (in kilograms per cubic meter).
  7. 7. The phenomena of reflection and refraction obey the laws of optics and depend on the angle of incidence as well as the acoustic mismatch.  Small differences in velocity also determine refraction. These properties explain the importance of using an acoustic coupling gel during transthoracic imaging. This is primarily due to the very high acoustic impedance of air.
  8. 8. Specular echoes are produced by reflectors that are large relative to ultrasound wavelength. Eg: endocardial and epicardial surfaces, valves, and pericardium. Targets that are small relative to the wavelength of the transmitted ultrasound produce scattering, and such objects are sometimes referred to as Rayleigh scatterers. Scattered echoes provide the substrate for visualizing the texture of gray-scale images.  The term speckle is used to describe the
  9. 9. Most commercial transducers employ ceramics, such as ferroelectrics, barium titanate, and lead zirconate titanate. Dampening (or backing) material, which shortens the ringing response of the piezoelectric material after the brief excitation pulse. An excessive ringing response lengthens the ultrasonic pulse and decreases range resolution.  At the surface of the transducer,
  10. 10. An important feature of ultrasound is the ability to direct or focus the beam . The proximal or cylindrical portion of the beam is referred to as the near field or Fresnel zone. When it begins to diverge, it is called the far field or Fraunhofer zone. Maximizing the length of the near field is an important goal of echocardiography.
  11. 11. The ultrasound beam is both focused and steered electronically, beam manipulation can be achieved through the use of phased array transducer. By adjusting the timing of excitation and adjustments in the timing allow the beam to be steered through a sector arc, resulting in a two-dimensional image. electronic transmit focusing of the beam
  12. 12. Focusing concentrates the acoustic energy into a smaller area, resulting in increased intensity .  By increasing beam intensity within the near field, the strength of returning signals is enhanced. An undesirable effect of focusing is its effect on beam divergence in the far field
  13. 13. Intensity varies across the lateral dimensions of the beam It is customary to measure the beam width at its half amplitude or intens.  At high gain settings, the weaker portion of the ultrasound beam is recorded and
  14. 14. Resolution has at least two components: spatial and temporal. Spatial resolution - smallest distance that two targets can be separated . Axial resolution lateral resolution
  15. 15. Commercial echographs have repetition rates between 200 and 5,000 per second.  M-mode , pulse repetition rates of between 1,000 and 2,000 per second are used. For two-dimensional imaging, repetition rates of 3,000 to 5,000 per second are necessary to create the 90-degree sector scan. Because all the pulses are devoted to a
  16. 16. • Requires more than one position. • Tilting pt to left improves ultrasound windows. • Rt lat decubitus-record aortic flow & congen disease. • Subcostal imaging • Suprasternal notch • Sitting position
  17. 17. • Mid portion & base of lv ,both leaflets of MV ,AV ,AO root ,LA &RV. • imaging plane is aligned parallel to long axis of lv. • Reduced endocardial definition & wall motion analysis difficult. • Medial angulation of the scan plane – RA & RV seen.
  18. 18. • one of the most important components of quantitation of ventricular function. • Qualitative and quantitative data derived from echocardiography, e.g., LV dimensions and wall thickness, can influence patient management and serve as potent predictors of outcomes • Chronic stable coronary artery disease, there is a consistent relationship between heart size and outcomes • The same applies to patients without heart failure. • Framingham Heart Study patients without a history of heart failure or myocardial infarction, LV size (by M-mode echocardiography) was an important predictor of subsequent risk of heart failure.
  19. 19. • M-mode line perpendicular to long axis of the heart and immediately distal to the tips of the mitral leaflets in thePLAX view • diastolic measurements septal wall thickness, the LV internal diameter at end diastole (LVIDd) and posterior wall thickness. In systole, the LV systolic diameter(LVIDs)
  20. 20. • clockwise rotation of 90 degrees • Pts lateral wall I placed to the observer”s right • LV is displayed as if viewed from apex • Apical level • Papillary muscle level - • Mitral valve level- Precise recording of mitral orifice in pts with MS.
  21. 21. -Basal level- aortic annulus, AV, coronory ostia, LA, TV, RVOT, PV & prox pa. -annulus regarded as clock face- LMCA at 4 & RCA at 11 -with slight superior angulation-bifurcation of PA
  22. 22. • Apical 4 chamber-After location of apical window ,all 4 chambers are optimally visualised when ful excursion of MV & TV leaflets occurs & true apex is seen. -false tendons of LV & moderator band of RV are normal variants. –crux of heart. • Apical 5 chamber –tilt the transducer into a shallower angle
  23. 23. • Apical 2 chamber- rotating the transducer CCW approx 60 deg. Similar orientation to RAO angiographic view LA APPENDAGE IS VIEWED. • Apical long axis view –transducer rotated CW 60 similar to PLAX. LV walls & ultrasound beam are parallel. Quantifying aortic valvular & subvalvular obstruction including HOCM.
  24. 24. • beam is oriented perpendicular to long axis of LV • better endocardial definition • septal defects are better delineated. • Only view that visualises superior portion of IAS • proximity of RV free wallto the transducer(pericardial tamponade) • IVC & hepatic veins are viewed.
  25. 25. Far Posterior tilt to visualise pulmonary veins
  26. 26. Anterior tilt to image entire length of LVOT
  27. 27. Tilting the plane far anteriorly LVOT not seen Trabeculated &outflow of RV, pulm valve, part of PA
  28. 28. • Depending on orientation of imaging planeto arch • PARALLEL- asc & des segments of aorta, origin of innominate, lt cca, lt sca, rpa are viewed. • PERPENDICULAR- RPA & LA are viewed
  29. 29. • fractional shortening and EF • Fractional shortening—the percentage change in the LV minor axis in a symmetrically contracting ventricle • FS(%)= (LVIDd – LVIDs)/LVIDd × 100% • FS = 25% – 45% (normal range) • LV volumes by 2D: 1. Prolate ellipsoid method. 2. Hemi-ellipsoid (bullet) method. 3. Biplane method of discs (modified Simpson’s)
  30. 30. • LV DIMENSIONS • SHORT AXIS diastole 3.5- 6.0 systole 2.1- 4.0 Long axis diastole 6.3- 10.3 systole 4.6- 8.4
  31. 31. LV volume women men Diastolic volume, mL 59-138 96-155 Diastolic volume/BSA, mL/m2 61+_ 13 67+_9 Systolic volume, mL 18-65 33-68 Systolic
  32. 32. • Fractional shortening—the % change in the LV minor axis in a symmetrically contracting ventricle • FS(%)= (LVIDd – LVIDs)/LVIDd × 100% • FS = 25% – 45% (normal range)
  33. 33. measu re wome n men Range mil d mo d seve re rang e mild mod sever e Linear metho d Endoca rdial FS % 27-45 22- 26 17- 21 ≤16 25- 43 20- 24 15- 19 ≤14 2D metho d
  34. 34. • AORTA annulus : 1.4- 2.6 cm at leaflet tips: 2.2- 3.6 asc aorta : 2.1- 3.4 LA PLAX : 2.3- 4.5 A4C med-lat : 2.5- 4.5 sup-inf 3.4-6.1 MITRAL ANNULUS end diastole: 2.7 +_ 0.4 end systole 2.9+_ 0.3
  35. 35. • RV wall thickness 0.2- 0.5 minor dimension 2.2- 4.4 length diastole 5.5-9.5 systole 4.2-8.1 PA annulus 1.0- 2.2 Main PA 0.9- 2.9 IVC diametre 1.2- 2.3
  36. 36. • Left ventricular mass (MassLV) = 0.8 × [1.04 (IVS + PWT + LVIDd)3 – LVIDd3] + 0.6 g
  37. 37. wo men men mild Mod Seve re Mild Mod Seve re LV mass 67- 162 163- 186 187- 210 ≥211 88- 224 225- 258 259- 292 ≥293 LV mass /BSA 43- 95 96- 108 109- 121 ≥122 49- 115 116- 131 132- 148 ≥149 Sept al thick ness, cm .6-.9 .9- 1.2 1.3- 1.5 ≥1.6 .6-.9 .9- 1.3 1.4- 1.6 ≥1.7
  39. 39. • One of the most significant developments of the last decades was the introduction of 3- dimensional (3D) imaging and its evolution from slow and labor-intense off-line reconstruction to real-time volumetric imaging • The major proven advantage of this technique is the improvement in the accuracy of the echocardiographic evaluation of cardiac chamber volumes. • Another benefit of 3D imaging is the realistic and unique comprehensive views of cardiac valves and congenital abnormalities
  40. 40. • The major breakthrough that allowed quality real-time imaging was the development of a microbeam former • When the entire crystal of the transducer head is sampled or covered with elements, the transducer is a dense array • The microbeam former is required for this arrangement to provide a communication of all of the approximately 3000 elements to the ultrasound system
  41. 41. • Transducer design • 2 D Matrix array of transducer elements helps generate the third dimension • The significant innovation that actually allows steering is making the elements electrically independent from each other • This allows generating a scan line that varies azimuthally and elevationally
  42. 42. • Modern 2D transducers therefore consist of thousands of electrically active elements that steer a scan line left and right as well as up and down
  43. 43. • Beam forming in three spatial dimensions 1. Beam forming constitutes the steering and focusing of transmitted and received scan lines 2. Significant portion of the beam steering is done within the transducer in highly specialized integrated circuit 3. The main system steers at coarse angles, but the transducer circuits steer in fine increments in a process termed microbeam forming 4. Summing is the act of combining raw acoustic information from each element to generate a scan line and by summing these in a sequence (first in the transducer and then subsequently in the system)
  44. 44. • There are two major black and white modes run in an electronically steered 3D system • Live mode where the system scans in realtime three dimension • Gating, this time only four to eight beats, allows a technique to generate wider volumes while maintaining frame rate • 3 D modes 1.Live 3D mode–instantaneous 2.3D zoom–instantaneous 3.Full-volume–gated 4.3D color Doppler–gated
  45. 45. • Display of 3D information 1.A 3D data set consists of bricks of pixels called volume elements or voxels • A process known as cropping can be used to cut into the volume and make some voxels invisible • 3D data sets of voxels are turned into 2D images in a process known as volume rendering
  46. 46. • All 3D echocardiography is subject to the laws of physics. • Artifacts such as ringing, reverberations, shadowing, and attenuation occur in three and two dimensions. • . The constraints of a 3D image are bounded by: (1)Frame rate, (2) 3D volume size, (3) Image resolution.
  47. 47. • 1) Direct evaluation of cardiac chamber volumes without the need for geometric modeling • 2) Noninvasive realistic views of cardiac valves and congenital abnormalities , helpful for showing a variety of pathologies and assessing the effectiveness of surgical or percutaneous transcatheter interventions • 3) Direct3D assessment of regional LV wall motion aimed at objective detection of ischemic heart disease at rest and during stress testing ,as well as quantification of systolic asynchrony to guide ventricular resynchronization therapy • 4) 3D color Doppler imaging with volumetric quantification of regurgitant lesions shunts ,and cardiac output • 5) Volumetric imaging and quantification of myocardial perfusion
  48. 48. • True myocardial motion occurs in three dimensions, and traditional 2D scanning planes do not capture the entire motion of the heart • Quantifying implies segmenting structures of interest from the 3D voxel set • 3D quantification of the left ventricle typically employs a surface- rendered mesh • This allows accurate computation of
  49. 49. • Most studies have been done on mitral valve. Understanding about the mitral valve annulus, leaflet tethering, tenting volumes has improved with the advent of 3 D echocardiography
  51. 51. • B mode echoes from an interface that changes position will be seen as echoes moving towards and away from the transducer. • If a trace line is placed on this interface and the resulting trace is made to drift across the face of
  52. 52. • The resulting display shows motion of a reflector over distance and time – a distance time graph • The change in distance (dy) over a period of time dt is represented by the slope of the reflector line of motion.
  53. 53. • If this motion pattern is obtained on moving cardiac structures then the resulting images constitute M-mode echocardiography. • M-mode echocardiography is use to evaluate the morphology of structures, movement and velocity of cardiac valves and
  54. 54. Distance Time
  55. 55. • Amplitude • Velocity • Time intervals • Morphology
  56. 56. Amplitude = Y2 –Y1 Y1 Y2 Distance Time
  57. 57. Time interval = T2 – T1 T2T1 Distance Time
  58. 58. dy = Y2 –Y1 Y1 Y2 T1 T2 dt = T2 – T1 Slope = dy/dt = velocity
  59. 59. • The mitral valve has 2 leaflets – anterior and posterior. • Specific letters corresponding to systole and diastole are assigned to the m-mode tracing of the mitral valve.
  60. 60. EKG Tracing T-wave QRS complex P wave Systole Diastole
  61. 61. Distance SystoleDiastole Time
  62. 62. Phase of Cardiac Cycle Assigned Letters Diastole d,e,f, and a Systole c and d
  63. 63. Systole Diastole d c a f e d Time Distance
  64. 64. Systole Diastole e d Time Distance d-e amplitude
  65. 65. Systole Diastole Septum e Time Distance EPSS
  66. 66. Systole Diastole e d Time Distance d-e slope
  67. 67. Systole Diastole f e Time Distance e-f slope
  68. 68. M-mode at the Mitral Valve Amplitude Description Normal Value EPSS Measure e point to septal separation < 5 mm d-e Measures the maximum excusion of the mitral valve following diastolic opening. 17 to 30 mm
  69. 69. M-mode at the Mitral Valve Slope Description Normal Value d-e Measure rate of initial opening of the mitral valve in early diastole. 240 to 380 mm/s e-f Measures the rate of early closure of the mitral valve following diastolic opening. 50 to 180 mm/s
  70. 70. • Flail PMVL • Fluttering of the AMVL • Mitral Stenosis • LA myxoma
  71. 71. Distance SystoleDiastole Time B-bump on the AC shoulder.
  72. 72. Distance SystoleDiastole Time Premature Closure Premature Closure- closure on or before the onset of the QRS complex.
  73. 73. Distance SystoleDiastole Time Systolic anterior motion of the AMVL
  74. 74. Distance SystoleDiastole Time MV prolapse posterior leaflet
  75. 75. Distance SystoleDiastole Time MV Prolapse – both leaflet
  76. 76. Distance SystoleDiastole Time Flail posterior leaflet
  77. 77. Distance SystoleDiastole Time Aortic Regurgitation
  78. 78. Distance SystoleDiastole Time Sinus Rhythm Mitral Stenosis
  79. 79. Distance SystoleDiastole Time Atrial Fibrillation Mitral Stenosis
  80. 80. Distance SystoleDiastole Time Atrial Myxoma
  81. 81. Distance SystoleDiastole Time Vegetation
  82. 82. Distance SystoleDiastole Time
  83. 83. Distance SystoleDiastole Time
  84. 84. • The aortic valve has 3 cusps – right coronary, left coronary and non-coronary cusps. • The cusps imaged in the PLAX view are the right coronary and the non-coronary cusps.
  85. 85. M-mode at the Aortic Valve Coronary cusp Non-coronary cusp Anterior aortic root Posterior aortic root Left Atrium
  86. 86. M-mode at the Aortic Valve LA dimension Cusp Separation Aortic root
  87. 87. M-mode at the Aortic Valve LA dimension Cusp SeparationAortic root Measurements are made from leading edge to leading edge.
  88. 88. • Dilated LA • Dilated aortic root • Decreased excursion • Premature opening • Premature closing • Exaggerated anterior motion of Aortic Root
  89. 89. • Reduced anterior motion of Aortic Root • Thickening • Calcification • Vegetations • Bicuspid valve • Prosthetic valve • Aortic Regurgitation
  90. 90. M-mode at the Aortic Valve Premature Opening Opening of the AV before the onset of the QRS complex Seen in Elevated LV-EDP
  91. 91. M-mode at the Aortic Valve Premature Closure Closure of the AV before the onset of the T wave Seen in IHSS
  92. 92. M-mode at the Aortic Valve Bicuspid Valve Eccentric closure line Seen when there is a Bicuspid aortic valve
  93. 93. M-mode at the Aortic Valve Decreased Cusp Separation Seen in Aortic Stenosis
  94. 94. M-mode at the Aortic Valve Seen in aortic sclerosis Thickened, calcified aortic valve leaflet.
  95. 95. M-mode at the Aortic Valve Seen in Mitral Stenosis Reduced anterior motion of aortic root
  96. 96. M-mode at the Aortic Valve Exaggerated anterior motion of aortic root Seen in Mitral Regurgitation
  97. 97. Aortic Regurgitation
  98. 98. Aortic Regurgitation
  99. 99. Aortic Regurgitation
  100. 100. LVPW excursion
  101. 101. LVPW max velocity = slope
  102. 102. Post Infarct
  103. 103. Pericardial Effusion
  104. 104. • Thickening of the IVS and LVPW • Movement of the IVS and LVPW
  105. 105. • IVSd • IVS excursion • IVSs M-mode Measurement
  106. 106. • LVIDd • LVIDd index • LVIDs • LVIDs index M-mode Measurement
  107. 107. • LVPWd • LVPW excursion • LVPW max excursion velocity • LVPWs M-mode Measurement
  108. 108. • % IVS thickening • % LVPW thickening • IVS/LVPW ratio M-mode LV Calculation
  109. 109. M-mode LV Calculation FS = LVIDd – LVIDs LVIDd
  110. 110. M-mode LV Calculation EF = LVIDd3 – LVIDs3 LVIDd3
  111. 111. M-mode LV Calculation IVS % thickening = (IVSs – IVSd) x 100 IVSd
  112. 112. M-mode LV Calculation LVPW % thickening = (LVPWs – LVPWd) x 100 LVPWd
  113. 113. M-mode LV Calculation LV Mass = 1.04 {(LVIDd + IVSd + LVPWd)3 – (LVIDd)3 } x 0.8 + 0.6g