ultrasound II and III

• b scan ultrasound used for

  diagnosing pregnancy, assessing viability of fetus, gestational age, fetal malformation, multiple pregnancies
• gestational age 


  crown-rump length, femur length, biparietal diameter, abdominal circumference
• M-scans (motion scan)


  detects movement of tissues within the body, especially the heart
• transesophageal echocardiography (TEE) procedure

  anaesthetics used to numb the throat, probe guided down the patient's throat, 10-15 minutes
• 2D TEE

  cross-sectional image of the heart obtained
• 3D TEE

  volume of the heart is imaged and displayed
• advantages of TEE

  better image quality than transthoracic scan, no interference of the ribs and lungs
• disadvantages of TEE

  invasive, anaesthetics required, small risk of physical injury
• doppler ultrasound


  non-invasive technique for measuring blood velocities within the body
• doppler effect 


  the apparent change in the frequency of a wave due to relative motion between the wave source and the observer
• laser doppler imaging 


  uses low-power helium-neon lasers to transcutaneously examine capillary flow
• diagnostic imaging uses pulse intensities of

  0.01Wcm^-2
• High-Intensity Focussed Ultrasound 


  used to stop internal bleeding especially in the liver
• Shock Wave Lithotripsy 


  used to break up bladder or kidney stones