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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 !