URR Abdomen Physics & Clinical Questions And Answers Latest Updates

Color Doppler demonstrates (x2) - average velocity & direction of flow Which artifacts will be seen with needles? (x3) - - Propagation speed artifact - Reverberation AKA resonance artifact - Bayonet artifact What happens if you decrease the color threshold? - reduce the color displayed - color threshold AKA priority - increase threshold if you don't see enough color If the entire image is too bright, what do you do first? - decrease the output power reverberation artifact due to gas production AKA _______ artifact - resonance artifact lower frame rate = increased/degraded temporal resolution - degraded temporal resolution For renal artery doppler evaluation, the angle should be _____. For intraparenchymal arteries, the angle should be _____. - - main RA = 60 - intraparenchymal = 20 Increasing _____ will most improve the ability to properly trace the contour of Doppler waveform. - Sweep speed A simple cyst could have artifactual debris in it in case of (x2) - - short distance from the transducer - volume averagingA contrast agent that consists of a cellulose suspension can better visualize which organ? - pancreatic tail Which artifact occurs when sampling vessels adjacent to a highly reflective structure like a bone? - Cross talk - mirror image of the waveform on the other side of the baseline Harmonic imaging increase (x3) and decrease (x3) - Increase - spatial resolution - contrast resolution - signal to noise ratio Decrease - reverberation - beam aberration - side lobes If you have trapezoidal field of view on linear array, which resolution are you degrading? - lateral resolution - Trapezoidal = 台形 - wider beams = less lateral resolution The number of lines of information used to create the color displayed on the image is called - Packet size - increase packet size = increase color display Sample angle controls the amount of color fill in a vessel evaluated with color Doppler. T/F - True - angle DOES matter to color fillingFile type for PACS system - DICOM = Digital Imaging & Communications in Medicine Name of transducer; order of the term in the name - 1. Shape of the transducer comes first 2. phased/sequential comes second e.g. - sector phased array - linear sequential array The bayonet artifact is - a type of propagation speed error, the tip of the needle appears curved When you are scanning MSK, you see this artifact; if the transducer is not parallel to the _____, it falsely appears hyperechoic/hypoechoic. - Anisotropy - scanning tendon - appears falsely hypoechoic (hypo=abnormal) - rock the transducer to make it parallel to the tendon How do you reduce the clutter/flash on a color Doppler image? - Decrease color priority/threshold In case of contrast live ultrasound, the mechanical index should be ______. Then turn on _____, and focal zone should be placed at ______ - - Mechanical Index = low (1.0) → prevent cavitation of microbubbles - turn on harmonics - focal zone at the area of interest Specular reflection occurs with - a large smooth structure = diaphragm - echogenic appearanceWhich vessel do you need to use angle correction during Doppler evaluation if you are evaluating a liver transplant? - Hepatic arteries & portal veins ______ adjusts the dynamic range AKA number of shades of gray on the image; when it decrease, dynamic range will get smaller = more black and white image. - Compression - Compression↓ = Dynamic↓ = shades of gray↓ = more black and white If you overestimate the angle between the beam and the blood flow, what happen to the velocity? - overestimate velocity - more angle = less cosine = more velocity - Shift = 2x f(TX) x V(blood) x cosθ