Lecture 11- Ultrasounds Flashcards

Question

when to do specular reflector longitudinal scan

Answer 1

* diaphragm * liver * kidney (loss of curve on outline)

Answer 2

* if boundary between 2 media has irregularities with a size similar to pulses' wavelength, the wavelength can be redirected into many directions * backscatter to transducer * rayleigh scatter

Answer 3

* acoustic resistance to sound as travels through medium * intensity increases w/ decreased density and with increased propagation speed

Answer 4

* bone: reflects too much, high speed (increased impedance, attenuation) * lung: too much scatter, low propagation speed

Answer 5

* machine malfunctioning * poor engineering * acoustic artifacts * operator error * interpretor error

Answer 6

* reverberation * shadowing * enhancement * reflectors * propagation speed * resolution

Answer 7

multiple echos or reflextion equally spaced (2+ reflectors in US beam)

Answer 8

* occurs when US can't pass through first structure * occurs when first structure is highly reflective, highly attenuated, highly scattered * sound does not penetrate, so acoustic shadow as useful artifact: renal claculi, cholelithiasis

Answer 9

* appears higher than normal echo amplitude after sound passes through fluid (increased "ease" of sound transmission through fluid; less impedence, faster speed) * may have fill in artifact

Answer 10

image may not be present or understated

Answer 11

* if tissue is not 1.54 km/sec, there will be incorrect depth of image * ex: fatty liver disease will change speed

Answer 12

* appears as 1, if closer than resolution of machine (try imaging in different plane to confirm)

Answer 13

* tissue equivalent phantom: cysts, solids, same resolution lateral and vertical

Answer 14

* very high US intensity can cause damage * **thermal injury**: exams that cause < 1 deg C elevation of temp is safe; anything > 41 degC can be harmful to fetus * **Cavitation**: bodies of gas/bubbles which can become excited by US (vibrate/shrink) leading to soft tissue injury * do not perform w/out reason, do not prolong scan w/out reason, use minimal output power needed

Answer 15

* transverse, sagittal plane images * can obtain obliques * array of elements w/in transducer

Answer 16

* Outer approach * Longitudinal: head on L, foot on R * Transverse: point toward pt's R * cavity approach changes orientation

Answer 17

* more white = more echogenic = more dense * more black = less echogenic = fluid * imaging choice for cystic vs solid

Answer 18

black fluid filled sac

Answer 19

* NPO (reduces bowel gas, GB should be "full") * look for free fluid & tap if found

Answer 20

* cholecystitis * Cholelithiasis * choledocholithiasis * GB polyps * echogenic bile

Answer 21

* pseudocysts * tumors * acute pancreatitis: swollen/large, less echogenic * chronic pancreatitis: damaged, more echogenic areas * hard to visualized when normal

Answer 22

* aorta is round w/ thicker wall * IVC is "collapsed" w/ thinner wall * fat around SMA * splenic vein courses opposite

Answer 23

* hydronephrosis * parenchymal changes * masses * cysts * congenital deformities * adrenals (not usually visualized)

Answer 24

* NOT MEDULLA VS CORTEX * center is echogenic due to the collecting system

Answer 25

* liver aids in R kidney (kidney usually less echogenic) * spleen aids in L kidney (spleen smaller)

Answer 26

* dilated collecting system in renal pelvis * +/- hydroureter

Answer 27

* enlargement * rupture * sickle cell * neoplasms

Answer 28

normally homogenous

Answer 29

* enlarged lymph nodes * masses * aorta * abscess

Answer 30

* visualize lumen walls and blood flow/clots

Answer 31

* thyroid * scrotum/testes * breast

Answer 32

* normally homogenous but can see cysts, malignant lesions, multi-nodular goiter, and developmental cysts * Parathyroids are not visible on US

Answer 33

* normall homogenous but can visualize edema, hydrocele, orchitis, epididymitis, carcinoma, seminoma, variocele

Answer 34

fluid in scrotal sac

Answer 35

* breast parenchyma is fairly homogenous * can detect masses, cysts, abscesses

Answer 36

* full urinary bladder for acoustic window * can do pre and post void for volume/residual volume

Answer 37

* echogenicity is usually homogenous * do transrectal approach to view size/masses

Answer 38

* can do because they have fontanelles and cartilage not bone, so we can see through it * evaluate for hydrocephalus (enlarged ventricular system w/ CSF)

Answer 39

* eye: retinal detachment * vascular: venous or arterial doppler

Answer 40

* change infrequency of sound as result of motion between sound and receiver (RBCs bounching) * Hz: doppler shifts of -10KHz to +10KHz in doppler studies * Negative #s: away from transducer * Positive #s: toward transducer

Answer 41

* 0 or 180 deg: no image as the sound beam and motion are parallel * 90deg: velocity is 0, use for imaging * motion mode for flow- graphic

Answer 42

* artifact when flow appears negative but is actually positive * the deeper the sample volume the more and the higher the frequency the more likely aliasing is to occur

Answer 43

* imaging and doppler in same study

Answer 44

* color is related to direction of flow in relation to transducer (pos/neg) * many times this may correspond to venous vs arterial flow

Answer 45

* heart imaging * has motion and imaging modes which show valvular abnormalities, wall motion analysis, ejection fraction, pericardial effusion * need to image through cardiac window (aka between bones)

Answer 46

* Peds: diamters 3-6mm; 3.5, 5.0, 7.5 MHz * Adults: 3.5, 2.25, 1.6 MHz * can do transesophageal approach for best resolution

Answer 47

* Focused Assessment w/ Sonography for Trauma (FAST) * Hepatorenal recess (morison pouch), peisplenic area, subxiphoid pericardial window, suprapubic window (Douglas pouch)

Answer 48

* extended fast * Hepatorenal recess (morison pouch), peisplenic area, subxiphoid pericardial window, suprapubic window (Douglas pouch) PLUS * bilateral hemithoraces and upper anterior chest wall