Ultrasound

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Ultrasound
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Ultrasound

• Ultrasound uses high frequency sound waves and
  their echoes.
• The ultrasound machine transmits high-frequency
  sound pulses.
• The sound waves hit a boundary between tissues
  (e.g. between fluid and soft tissue, soft tissue
  and bone).
• Some of the sound waves get reflected back to the
  probe, while some travel on further until they
  reach another boundary and get reflected.

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Ultrasound

• The reflected waves are picked up by the
  transducer and relayed to the machine.
• The machine calculates the distance from the
  transducer to the tissue or organ (boundaries)
  using the speed of sound in tissue and the time
  of the each echo's return.
• The machine displays the distances and
  intensities of the echoes on the screen, forming
  a two dimensional image.

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Ultrasound

• Transducer sends and receives high frequency
  sound waves
• Transducer must be in contact with structure
  being examined
• Ultrasound gel or obstetric lube used to make
  contact complete.

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Transducers

• Crystals vibrate at high frequency producing
  sound waves
• The sound waves are transmitted and received by
  the transducer
• The transducer is identified by the crystal
  array.
• The array is the way in which the crystals are
  arranged
• Linear array
• Convex array
• Sector scanner

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Linear array
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Convex Array
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Sector Scanner
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Sound wave reflection
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Ultrasound Wave Transmission
Transducer Sends and receives ultrasound waves
WATER
SOFT TISSUE
BONE / AIR / METAL
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Wave length

• Higher frequency shorter wavelength
• Shorter wavelength better resolution
• Better resolution view smaller objects
  with more detail
• Shorter wavelength less penetration
• Less penetration view objects close to surface
• Rectal exams 5 mgHz transducer
• Transabdominal 3 mgHz transducer

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Wave length

• Lower frequency Longer wavelength
• Longer wavelength less resolution
• Less resolution less detail
• Longer wavelength more penetration
• More penetration view deeper objects
• Rectal exams 5 mgHz transducer
• Transabdominal 3 mgHz transducer

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7 mHz
5mHz
3mHz
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Doppler Ultrasound

• Moving objects are scanned
• Objects moving away produce lower frequency
• Objects moving toward the transducer produce
  higher frequency
• Used to measure blood flow in heart and arteries

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Doppler Ultrasound
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3-D ultrasound

• Several two-dimensional images are acquired by
  moving the probes across the body surface or
  rotating inserted probes.
• The two-dimensional scans are then combined by
  specialized computer software to form 3D images.

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3-D ultrasound
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Use of ultrasound in mare reproduction

• Pregnancy as early as 10 days
• Twins
• Endometrial cysts
• Follicles
• Ovulation
• CL
• Ovarian tumors

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Use of ultrasound in mare reproduction

• Uterine edema
• Uterine fluid
• Fetal heartbeat
• Fetal well being
• Fetal sexing
• Placental health
• Guided injection for aborting one twin

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Day 11 twins
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Ultrasound Images of Day 10 15 of Pregnancy
Ultrasonic Anatomy of Pregnancy
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motile equine embryos
Day 12 Embryo Day 14 Embryo
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Day 20 Embryo
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Day 24 Embryo
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Day 30 Embryo
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Ultrasound Images of Day 15-45 of Pregnancy
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Uterus
Estrus
Diestrus
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Development of CL
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Primary Corpus Luteum
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Endometrial cyst
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Granulosa cell tumor
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Twin Reduction

• http//www.ivis.org/advances/Reproduction_Ball/fet
  al_reduction_ball/chapter_frm.asp?LA1