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Doppler and color flow principles.pptx for radiologist
- 2. Waves from astatic source Wave peaks evenly spaced around the source at 1 wavelength intervals
- 3. Waves from amoving source Source moving this way Old positions of source
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- 11. Stationary Target Towards Transducer Awayfrom Tranducer
- 22. Doppler Principle fd =2fo V Cos 0 c c is velocity of sound in body tissues(1540 m/s)
- 25. TYPES OF BLOODFLOW 1.Plug Flow 2.Laminar Flow 3.Pulsatile Flow 4.Turbulent Flow
- 26. 1.Plug Flow-all thefluid moves in the same speed.
- 28. 2.Laminar flow -there isparabolic distribution of velocities ….Fluid near the vessel wall moves slowly while in the centre moves faster.
- 31. 3.Pulsatile flow-It isseen in arteries with regular acceleration which resembles plug flow-to constant flow which is laminar –and then there is de-acceleration. In some vessels there is reverse flow in part of cardiac cycle
- 33. 4.Turbulent Flow-This is a disorderly flowthat occurs in areas of stenosis and downstream from bifurcation
- 37. Doppler Spectrum Assessment Window •The clear area underneath the spectrum is called the window. • Received Doppler shift consist of a range of frequencies. • Narrow range of frequencies will result in a narrow display line.
- 40. Spectrum Broadening Loss ofthe Spectral window is called Spectral Broadening.
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- 52. A B CD Dynamics Of Flow Spectral Broadening Turbulance
- 54. Clinical Sonography APractical Guide 4th Edition 2007.djvu
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- 71. CW DOPPLER Continuousbeam emission from one transducer …received from other. Both transducers encased in single housing. Can only examine superficial vessels Image can not be formed. Used by vascular surgeons…usually not used in radiology department. Gynecologists use to monitor umb art flow A simple, cost effective system.
- 75. CW doppler Alwaystransmitting and receiving Just look at the difference in frequency So – don’t know depth ! Can avoid this (somewhat) by using intersecting beams.
- 82. Pulsed Doppler C B A A =PRP B = Pulse Duration C= Reception Time
- 83. Pulsed wave Doppler Pulses – just like real time scanning Can find depth Need to “gate” analysis of received pulse, so we know where the moving objects are…
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- 99. Spectral Display Time Mono-phasic Flow Flowon just on side of the Baseline.
- 100. Spectral Display Time Bi-phasic Flow Flowstart on one side of the Baseline and then crosses to the other.
- 101. Spectral Display Time Tri-phasic Flow Flowstart on one side of the baseline side, then crosses to the other, then returns to the original side.
- 102. Spectral Display Time Bidirectional Flow Flowwhich occurs simultaneously on both sides of the baseline.
- 103. Beam Flow Angle Ø = 0° Parallel to flow - Optimum shift Ø = 1° to 89° Shift is reduced Ø = 90° Perpendicular to flow - No shift
- 104. Angle to Flow AngleCosine 0 1.00 15 0.97 45 0.71 60 0.50 75 0.26 90 0.00
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- 106. Angle effects MaximumDoppler shift at 0 degrees minimum at 90 degrees – proportional to the Cosine of the angle between the beam and direction of travel Direction of movement Alignm ent of beam
- 107. Doppler Angle (0degree)
- 108. Doppler Angle /Doppler Shift
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- 192. HEPATOPETAL/HEPATOFUGAL FLOW DUPLEX IMAGING/TRIPLEXIMAGING…NO COLOR FLOW ON DUPLEX. FRAME RATE..no of time the image is refereshened PRF…LOW PRF..HIGH VELOCITY..ALAISAING. HIGH RESISTANCE/LOW RESISTANCE FLOW UMBLICAL ARTERY OVARIAN ARTERY…MALIGNANT-BENIGN TUMORS PERIPRAL VESSELS PARVUS TARDUS FLOW..FIG 4.9. INTIMA..MEDIA..ADVENTITIA
- 205. MCA…soon after origin Angleclose to zero degree
- 206. PSV above 70cm/sec…if seen inless than 30 weeks gestation….. needs transfusion.
- 209. RULE OF THUMB..DECLAREMILD TO MODERATE ANAEMIA IF AT 20WEEKS….MORE THAN 40CM/SEC AT 25WEEKS…. MORE THAN 50CM/SEC AT 30WEEKS … MORE THAN 60CM/SEC AT 35WEEKS … MORE THAN 70CM/SEC AT 40WEEKS… MORE THAN 80-100CM/SEC NORMAL VALUE IS 30% LESS
- 211. 1.How can youreduce aliasing in color Doppler study. 2.How CW Doppler differs from PW Doppler. 3.What is spectral broadening…Why it is seen in Doppler study. 4.How Power Doppler differs from Color Doppler. 5.What is the difference between low resistance and high resistance blood flow…How Doppler study could help in measuring blood flow resistance.
- 212. 1.What is turbulentflow. How it will appear on spectral Doppler waveform. 2.What is a reverberation artifact. How can it be reduced/minimized. 3.What is meant by angle correction in Doppler study. What is its role in RI and velocity measurements. 4.How Power Doppler differs from Color Doppler. 5.How can you reduce aliasing in color Doppler study.
Editor's Notes
- #26 MRA is direct visualization of flowing blood
- #37 Spectral Doppler Modes Pulsed Wave Doppler Continuous Wave Doppler (with cardiac option) In Pulsed Wave and Continuous Wave Doppler, you select the area of interest by positioning a Doppler cursor within the 2-D image. Pulsed Wave Doppler displays velocities within the range bounded by the Doppler gate on the cursor. Both let you simultaneously display the 2-D image and Doppler spectral information or independently display spectral Doppler information. Auxiliary Continuous Wave Doppler (with cardiac option) Auxiliary Continuous Wave Doppler uses a special auxiliary transducer. Because of its small size, the auxiliary transducer can access any area requiring documentation of blood flow. You position the auxiliary transducer independently of the transducer you are using for the 2-D image. Auxiliary Continuous Wave Doppler displays only a full-screen spectral display. HPRF (High Pulse Repetition Frequency) High Pulse Repetition Frequency (HPRF) allows increased velocity detection at depth and localization of flow. Use HPRF Pulsed Doppler mode when you want the Doppler velocity scale higher than the system can provide in standard Pulsed Doppler mode at a specific gate depth. HPRF generates multiple sample volumes displayed with smaller secondary gates in addition to the standard gate size of the primary sample volume. Excellent Sensitivity.
- #40 Spectral Doppler Modes Pulsed Wave Doppler Continuous Wave Doppler (with cardiac option) In Pulsed Wave and Continuous Wave Doppler, you select the area of interest by positioning a Doppler cursor within the 2-D image. Pulsed Wave Doppler displays velocities within the range bounded by the Doppler gate on the cursor. Both let you simultaneously display the 2-D image and Doppler spectral information or independently display spectral Doppler information. Auxiliary Continuous Wave Doppler (with cardiac option) Auxiliary Continuous Wave Doppler uses a special auxiliary transducer. Because of its small size, the auxiliary transducer can access any area requiring documentation of blood flow. You position the auxiliary transducer independently of the transducer you are using for the 2-D image. Auxiliary Continuous Wave Doppler displays only a full-screen spectral display. HPRF (High Pulse Repetition Frequency) High Pulse Repetition Frequency (HPRF) allows increased velocity detection at depth and localization of flow. Use HPRF Pulsed Doppler mode when you want the Doppler velocity scale higher than the system can provide in standard Pulsed Doppler mode at a specific gate depth. HPRF generates multiple sample volumes displayed with smaller secondary gates in addition to the standard gate size of the primary sample volume. Excellent Sensitivity.
- #99 Spectral Doppler Modes Pulsed Wave Doppler Continuous Wave Doppler (with cardiac option) In Pulsed Wave and Continuous Wave Doppler, you select the area of interest by positioning a Doppler cursor within the 2-D image. Pulsed Wave Doppler displays velocities within the range bounded by the Doppler gate on the cursor. Both let you simultaneously display the 2-D image and Doppler spectral information or independently display spectral Doppler information. Auxiliary Continuous Wave Doppler (with cardiac option) Auxiliary Continuous Wave Doppler uses a special auxiliary transducer. Because of its small size, the auxiliary transducer can access any area requiring documentation of blood flow. You position the auxiliary transducer independently of the transducer you are using for the 2-D image. Auxiliary Continuous Wave Doppler displays only a full-screen spectral display. HPRF (High Pulse Repetition Frequency) High Pulse Repetition Frequency (HPRF) allows increased velocity detection at depth and localization of flow. Use HPRF Pulsed Doppler mode when you want the Doppler velocity scale higher than the system can provide in standard Pulsed Doppler mode at a specific gate depth. HPRF generates multiple sample volumes displayed with smaller secondary gates in addition to the standard gate size of the primary sample volume. Excellent Sensitivity.
- #100 Spectral Doppler Modes Pulsed Wave Doppler Continuous Wave Doppler (with cardiac option) In Pulsed Wave and Continuous Wave Doppler, you select the area of interest by positioning a Doppler cursor within the 2-D image. Pulsed Wave Doppler displays velocities within the range bounded by the Doppler gate on the cursor. Both let you simultaneously display the 2-D image and Doppler spectral information or independently display spectral Doppler information. Auxiliary Continuous Wave Doppler (with cardiac option) Auxiliary Continuous Wave Doppler uses a special auxiliary transducer. Because of its small size, the auxiliary transducer can access any area requiring documentation of blood flow. You position the auxiliary transducer independently of the transducer you are using for the 2-D image. Auxiliary Continuous Wave Doppler displays only a full-screen spectral display. HPRF (High Pulse Repetition Frequency) High Pulse Repetition Frequency (HPRF) allows increased velocity detection at depth and localization of flow. Use HPRF Pulsed Doppler mode when you want the Doppler velocity scale higher than the system can provide in standard Pulsed Doppler mode at a specific gate depth. HPRF generates multiple sample volumes displayed with smaller secondary gates in addition to the standard gate size of the primary sample volume. Excellent Sensitivity.
- #101 Spectral Doppler Modes Pulsed Wave Doppler Continuous Wave Doppler (with cardiac option) In Pulsed Wave and Continuous Wave Doppler, you select the area of interest by positioning a Doppler cursor within the 2-D image. Pulsed Wave Doppler displays velocities within the range bounded by the Doppler gate on the cursor. Both let you simultaneously display the 2-D image and Doppler spectral information or independently display spectral Doppler information. Auxiliary Continuous Wave Doppler (with cardiac option) Auxiliary Continuous Wave Doppler uses a special auxiliary transducer. Because of its small size, the auxiliary transducer can access any area requiring documentation of blood flow. You position the auxiliary transducer independently of the transducer you are using for the 2-D image. Auxiliary Continuous Wave Doppler displays only a full-screen spectral display. HPRF (High Pulse Repetition Frequency) High Pulse Repetition Frequency (HPRF) allows increased velocity detection at depth and localization of flow. Use HPRF Pulsed Doppler mode when you want the Doppler velocity scale higher than the system can provide in standard Pulsed Doppler mode at a specific gate depth. HPRF generates multiple sample volumes displayed with smaller secondary gates in addition to the standard gate size of the primary sample volume. Excellent Sensitivity.
- #102 Spectral Doppler Modes Pulsed Wave Doppler Continuous Wave Doppler (with cardiac option) In Pulsed Wave and Continuous Wave Doppler, you select the area of interest by positioning a Doppler cursor within the 2-D image. Pulsed Wave Doppler displays velocities within the range bounded by the Doppler gate on the cursor. Both let you simultaneously display the 2-D image and Doppler spectral information or independently display spectral Doppler information. Auxiliary Continuous Wave Doppler (with cardiac option) Auxiliary Continuous Wave Doppler uses a special auxiliary transducer. Because of its small size, the auxiliary transducer can access any area requiring documentation of blood flow. You position the auxiliary transducer independently of the transducer you are using for the 2-D image. Auxiliary Continuous Wave Doppler displays only a full-screen spectral display. HPRF (High Pulse Repetition Frequency) High Pulse Repetition Frequency (HPRF) allows increased velocity detection at depth and localization of flow. Use HPRF Pulsed Doppler mode when you want the Doppler velocity scale higher than the system can provide in standard Pulsed Doppler mode at a specific gate depth. HPRF generates multiple sample volumes displayed with smaller secondary gates in addition to the standard gate size of the primary sample volume. Excellent Sensitivity.
- #103 The Cosine Relationship COS q -Beam parallel to flow -COS 0° = 1, optimum sensitivity -Beam perpendicular to flow -COS 90° = 0, no sensitivity [Review: Define cosine and its importance in Doppler.] [Example] If sound beam was propagated at the same angle as the blood flow, the COSq would be 1 and there would be maximum velocity sensitivity. If the sound beam-to-blood flow angle is between a 1 and 89 degree angle, the detected Doppler frequency shift is reduced according to the cosq term. If the beam is perpendicular, or 90 degrees to the flow, the cosqis 0 and there will be no detected Doppler shift. This demonstrates how important it is to have a good Doppler angle to the blood flow. Note: When a sonographer wishes to identify the presence of flow, this interdependence of flow and the cosine is unimportant (as long as the incident angle is something other than 90 degrees).
- #104 The Cosine Relationship COS q -Beam parallel to flow -COS 0° = 1, optimum sensitivity -Beam perpendicular to flow -COS 90° = 0, no sensitivity [Review: Define cosine and its importance in Doppler.] [Example] If sound beam was propagated at the same angle as the blood flow, the COSq would be 1 and there would be maximum velocity sensitivity. If the sound beam-to-blood flow angle is between a 1 and 89 degree angle, the detected Doppler frequency shift is reduced according to the cosq term. If the beam is perpendicular, or 90 degrees to the flow, the cosqis 0 and there will be no detected Doppler shift. This demonstrates how important it is to have a good Doppler angle to the blood flow. Note: When a sonographer wishes to identify the presence of flow, this interdependence of flow and the cosine is unimportant (as long as the incident angle is something other than 90 degrees).