What is a logarithm? Number of 10's that are multiplied to create original number What is the log of 1000? 3 What is the log of 10,000? 4 Is distance and attentuention a) inversely related b) directly related c) not related Directly related What 3 processes contribute to attentuation? 1) Reflection 2) Scattering 3) Absorption What are the 2 forms of reflection? Specular and Diffuse What boundary is found with specular reflection? Smooth boundary Sound is reflected in only one direction What boundary is found with Diffuse reflection? Irregular surface boundary Sound is reflected in more than one direction What is the medium of lung tissue that causes scattering? Air What is the definition of PRF? Pulse repetition frequency The number of pulses per 1 second What is the definition of PRP? Pulse repetition period Time from beginning of 1 pulse to the beginning of the next pulse What is pulse duration? The time from beginning of the pulse to the end or "talk time" What is power? Rate of energy transfer measured in watts What is Propagation speed? The time it takes to travel through medium. The medium determines the speed. Why does sound travel fast in bone? Bone has a higher stiffness level and lower density level What is Frequency? The number of events in a specific duration of time What is intensity? Concentration of energy in sound beam What is the relationship of Period and Frequency? Inversely related What is the distance of one complete cycle? Wavelength Why does sound travel slow in air? Density is increased and stiffness is decreased What are units of attenuation? dB What is a quick way to find log? Count the number of 0's 100=2 1000=3 10,000=4 Water has low attenuation T or F True Air has high attenuation T or F T As path length increases, what happens to Attenuation coefficent? a) increases b) decreases c) remains the same Remains the same When scanning a carotid artery which transducer do you choose? 1) 7.0 2) 3.5 7.0 What is the unit of Attenuation coefficient? dB/cm In a boundary where impedance is the same, what part of sound wave is reflected back? 0% is reflected 100% is transmitted What law is demonstrated by rules of refraction? Snell's Law Does attentuation increase or decrease as path length increases? increase What are the names for Lateral Resolution? Hint - 4 Lateral Angular Transverse Azimuthal What are 3 synonyms for PZT? Element Crystal Ceramic What is the definition of Hemodynamics? Study of blood moving through circulatory system What does Volume rate measure? How much What does Velocity measure? How fast Units of flow are volume/time or distance/time Volume/time Units of velocity are volume/time or distance/time Distance/time What are the 3 forms of blood flow? Pulsatile Phasic Steady Pulsatile flow accelerates and decelerates from Cardiac Contraction Phasic blood flow accelerates and decelerates from Respiration Steady flow occurs when fluid moves at a _____ speed of velocity? Slow Constant Fast Constant Laminar flow is Chaotic or Aligned and Paralell Alligned and Paralell What is the Reynolds number for Laminar flow? less than 1500 Turbulent flow is Chaotic or Aligned and paralell Chaotic What are sounds associated with turbulent flow? Murmur, Bruit, and thrill What is the definition of transducer? Transforms electrical energy into acoustic energy Definition of Pulser? Determines the amplititude, pulse repetition period (PRP) and pulse repetition frequency (PRF) Definition of Beam Former? Determines the firing delay pattern for phased array systems Definition of Receiver? Transforms signals from transducer into a form suitable for display Definition of Storage? Archives U/S studies in videotape, paper printout, photos, film, CD or hard drives Definition of Master Synchronizer? Maintains and organizes timing What is line density? Spacing between sound beams What is range ambiguity? Inability to determine exact location of moving red blood celss with CW (continuous wave) What is pixel density? Number of pixels per inch What is spatial resolution? High pixel density Improved Image Greater detail What are artifacts? Errors in imaging What is reverberation? Multiple equally-spaced echoes - resembles venetian blinds What is a Comet Tail? Ring down artifact appearing as solid hyperechoic line What is shadowing? Hypoechoic or anechoic region extending downward What is edge shadow? Hypoechoic region extending along edge of curved reflector What is enhancement? Hyperechoic region beneath tissue with low attentuation What is focal enhancement? Side to side region appears brighter than deeper tissue aka focal banding What is Mirror image? Artifact showing Deeper image redirected toward 2nd structure What is Crosstalk? Mirror image on Spectral Doppler display What is a speed error? Sound wave propagates through a medium other than that of soft tissue What is propagation speed error? Range error artifact or range ambiguity artifact What are side lobes? Created by a single crystal transducer or mechanical probe What are grating lobes? Created by Array transducer There are no known harmful bioeffects from U/S exams. T or F T What are the units of Dynamic range? dB Slice thickness and Elevational resolution is Directly related Inversely related Not related Directly Related Which mode is the 1st grey scale imaging? A Mode B Mode M Mode B Mode Expiration increases or decreases venous flow in legs? Increases The difference between received and transmitted frequencies is called Doppler Frequency Doppler Shift Power Doppler Doppler Shift Phased Array is reserved for Linear Transducer T or F F What type of converter is used in U/S? Digital Analog Digital Why does a gallstone have a shadow on U/S? Too much attenuation Too little attenuation No attenuation Too much attenuation What is a synonym of propagation speed error? Range ambiguity What does color Doppler provide information about? Range resolution What angle is best to scan carotid artery? 60 degrees or less Power Doppler is also called Energy Mode Artifact is An error in imaging Which mode gives information about time? A Mode B Mode M Mode M Mode What are 2 controls on video monitor that the sonographer cannot change? Contrast and Brightness On inspiration the Diaphragm Ascends Descends Stays the same Descends Reynolds number determines laminar vs turbulent flow T or F T Phasic flow is related to Cardiac contraction Velocity Respiration Respiration Spacial resolution improves with high or low line density? High line density What does ALARA mean? As Low As Reasonably Achieved What is dynamic range? The ratio of largest to smallest signal strength What are 5 requirements of contrast agents? 1) Safe 2) Metobolically inert 3) Long lasting 4) Strong reflector of U/S 5) Small enough to pass through capillaries Harmonic frequency is ________ times fundemental frequency. 2 3 10 2