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Faisal M. Shembesh
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Sound Energy Is A Mechanical One
Unlike The Electromagnetic Energy.
The medium is required for sound waves to be
propagated.
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Compression and rarefaction
Wave length
Ultrasound transducer
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Ultrasound
Frequency is determined by the sound source. Unit of frequency cycle /sec.(Hz.)
1 cycle / sec. 1 Hz.1000 cycle / sec. KHz.
1000,000 cycle / sec. MHz.
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Classification Of Sounds According To
Frequency
Ultrasound
Diagnostic medical ultrasound
Audible sound
20Hz
Mega Hz
20.000Hz
20Mega Hz
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SPEED OF SOUND:
B Bulk Modulus (Stiffness)P Density F !
S.O.S.(m/s)Material
600Lung
1460Fat
1500A.Humor
1555Liver
1560Blood
1565kidney
1600muscle
1620lips
4080skull
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Transmission and reflection at interfaces
acoustic impedance:property of tissue that detrmined The quantity of reflected echoes.
Z=PC
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ImpedanceTissue
0.0004x10Air
0.18x10Lung
1.34x10Fat
1.48x10Water
1.65x10Liver
1.65x10blood
1.66x10kidney
1.71x10Muscle
7.8x10Skull bone
6
6
6
6
6
6
6
6
6
Z1 _ Z2
R= --------------
Z1 + Z2
Transmitted beam
Reflected beam
Z1 Z2
Tissue 1 Tissue 2
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DIFFUSE AND SPECULAR REFLECTORS
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Scatters
ECHOES FROM SCATTERING GOOD AND BAD EFFECTS
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ATTENUATION COEFFICINT IN TISSUES
Attenuation at 1Mhz(dB/cm)Tissue
0.0002
0.18
0.5
1.2
Water
Blood
Liver
Muscle
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FREQUENCY DEPENDENCE OF ATTENUATION
ATTENUATION TISSUE DEPENDENT MAINLY ON
FREQUENCY
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5Mhz 3.5Mhz
DOPPLER PHYSICS
DOPPLER SHIFTS FOR AUDIBLE SOUNDSSOUND SOURCE
RELATIVE MOTION - DIFFERENCE IN FREQUENCY
DOPPLER SHIFTS IN MEDICAL US
5 MHz.TRANDUCER
5.6 MHz.
4.5 MHz.
DOPPLER EQUATION:* REFLECTOR SPEED.* U.S. FREQUENCY.
* SPEED OF SOUND.* DOPPLER ANGLE.
EFFECT OF DOPPLER ANGLE
SPECTRAL BROADNING CAUSED BY TRANSDUCER
ANGLE CORRECTION AND ANGLE ERROR
CONTINUOUS VS. PULSED WAVE DOPPLER
Continuous wave doppler
OPERATOR CONTROL FOR C.W.D.
• POWER CONTROL.
• RECEIVER SENSETIVITY.
• LOUDNESS OF VOLUME.
• WALL FILTER CONTROL.
Pulsed wave doppler
OPERATOR CONTROL FOR P.W.D.
• POWER CONTROL.
• RECEIVER SENSETIVITY.
• LOUDNESS OF VOLUME.
• WALL FILTER CONTROL.
• RANGE GATE POSITION.
• GATE (SAMPLE VOLUME) SIZE.
• FLOW ANGLE CURSOR.
Sample volume control
SPECTRAL ANALYSIS
Parameters used in spectral analysis
FLOW SPECTRAL CHANGES
TYPES OF FLOW
ALIASING IF THE P.R.F. IS < TWICE OF THE
DOPPLER SIGNAL FREQUENCY ALIASIN WELL OCCUR
COLOUR DOPPLER (FLOW MAPPING)
COLOUR DOPPLER
COLOUR FLOW MAPPING
ALIASING IN COLOUR DOPPLER
ADVANTEGES OF COLOUR DOPPLER
DISADVANTEGES OF COLOUR DOPPLER
RENAL ULTRASOUND
Objectives
• Clinical indications for performing renal US
• Approach to performing the US study
• Normal anatomy
• Abnormal findings
• Clinical Impact
Clinical Indications for Renal Ultrasound
• Suspected renal colic
– Colicky flank pain radiating to groin
– Hematuria
• Clinical question:
– Presence of hydronephrosis
– Absence of other pathology (AAA)
Performing the Study
• Patient preparation:
– none
• Transducer: 3.0MHz or 3.5 MHz
– 5.0 MHz for thin patient
• Patient positioning
– Supine
– Posterior oblique, lateral decubitus, prone
Anatomy
• Kidneys are retroperitoneal, T12 - L4
• Right kidney is lower than the left kidney
• Right kidney is posterio-inferior to liver & gallbladder
• Left kidney is inferior-medial to the spleen
• Adrenal glands are superior, anterior, medial to each kidney
Celiac
axis
SMA
Renal artery
Renal vein
Hepatic
Veins
Right
kidney
Left
kidney
Liver
Spleen
Approach to Scanning
• Right kidney scanning approach: anterior, lateral, posterior
• Liver is the acoustic window
• Left kidney: requires a posterior approach, through the spleen
• Air-filled bowel impedes anterior scanning
I
LIVER STOMACH
IVC
AORTAK K
S
Anatomy
• 9-12 cm long, 4-5 cm wide, 3-4 cm thick
• Gerota’s fascia encloses kidney, capsule, perinephric fat
• Sinus
– Hilum: vessels, nerves, lymphatics, ureter
– Pelvis: major and minor calyces
• Parenchyma surrounds the sinus
– Cortex: site of urine formation, contains nephrons
– Medulla: contains pyramids that pass urine to minor calyces. Columns of Bertin separate pyramids
Renal capsuleCortex
Medullary pyramids
Minor
Calyx
Kidney Anatomy
Medulla
Sinus
Major
Calyx
Sonographic Appearance
• Ureters are normally not seen
• Renal pelvis is black when visible
• Renal sinus is echogenic due to fat
• Medullary pyramids are hypoechoic
• Cortex is mid-gray, less echogenic than liver or spleen.
• Capsule is smooth and echogenic
Liver
Diaphragm
Sinus
Cortex
Anterior
Posterior
Superior Inferior
Right Kidney Long Axis
Right Kidney Short Axis
Vertebral
Body
R KidneyAorta
Renal a.
GB
IVC
Liver
Anterior
Posterior
Right Left
Left Kidney Long Axis
Anterior
Posterior
Superior Inferior
Spleen
Kidney
Rib
Shadow
Left Kidney Short Axis
Anterior
Posterior
Right LeftLiver
Spleen
L Kidney
THANK YOU !