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Clin D III > Ultrasound > Flashcards

Ultrasound Flashcards

1
Q

The Medical Sonographer

RDMS- registered diagnostic medical sonographer

A

Typical 2 year education program
Now typically tied to Bachelor’s degree
Didactic and Clinical

Other routes, i.e. on the job (OTJ) cross training
National boards
Different specialties

Ultrasound physics as additional part of certification

Ultrasound Provider- UP
Mid level provider for ultrasound department
Has not “taken off” except in echo

Masters Degree

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2
Q

OB/GYNE

TAS

A

transabdominal approach
Full urinary bladder
Later pregnancy (very late may not need full bladder), ovaries, uterus

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3
Q

OB/GYNE

EVS

A

endovaginal sonography
Empty bladder
Early pregnancy, ovaries, uterus
Frequencies of 5-10 MHz
Limited FOV (Field of View)

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4
Q

First Trimester Studies
indications

A

Ectopic pregnancy

Threatened Ab
Cervix open vs closed
Fetal viability/death
Anembryonic pregnancy (blighted ovum)

Sonographic dates
Gestational sac size (see Figure)
Crown Rump length (see Figure)

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5
Q

gesttional sac size

A

measure the size of the ovum when the fetus isnt big enough to measure

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6
Q
A

crown to rump size

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7
Q

2nd and 3rd trimesters
fetal measurements (4)

A

Fetal measurements
BPD- biparietal diameter
HC- head circumference
AC- abdominal circumference
FL/HL- femoral length to humeral length ratio

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8
Q

obgyn

IUGR- intrauterine growth retardation

A

baby isnt growing at proper rate

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9
Q

OBGYN

PROM- premature rupture of membranes

A
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10
Q
A

As seen in “Volume” ultrasound mode
3D look

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11
Q

Biophysical Profile

A

Level II US (See table)

Fetal assessment
Number, position, lie
Breathing, movements, tone, reactive heart rate

Fetal Data
Measurements BPD, FL, AC
Systematic organ review

Placenta, amniotic fluid amount
Cord

measurements taken to grade the baby, this is done if there are concerns for baby.

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12
Q

US Guided OB Procedures

Amniocentesis

Chorionic Villus sampling (CVS)

A

Amneocentesis
AFP level abnormal
Fetal lung maturity check
Level of fluid

CVS can help identify certain genetic diseases, including problems with chromosomes. These cell structures hold fetal DNA.

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13
Q

Gyne Exams

A
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14
Q

Transducers

A

Change one form of energy into another

Piezoelectric crystals (created a voltage when mechanically deformed) –>The active component of transducer
Emits ultrasound frequency waves

Conductivity gel is needed to make an image

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15
Q

frequency

A

Numbers of cycles per second
Hertz or Hz
Hearing 30-20,000 Hz
US uses >20,000
Clinical imaging 2MHz –10 MHz

Determined by sound source
Transducer named for main frequency

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16
Q

Beam Anatomy

A

Beam starts as size of transducer

Converges to focal point
Focal length
Diverges in the far zone
Larger diameters have further focal length

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17
Q

Ultrasound transducer beam

A

Sound waves in transducers don’t diffract
Most energy transmitted along main central beam

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18
Q

Resolution

A

Lateral resolution
2 points distinguishable when side by side

Depth resolution
2 pts distinguishable when “front to back”

Wavelength influences resolution
Higher frequency, higher resolution (less penetration)

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19
Q

Pulsed Waves

A

Collection of number of cycles that travel together
On time- transducer sending
Off time- receiving
Capturing return trip information

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20
Q

Receiver

A

As image depth increases, the pulse repetition frequency decreases (number of pulses per second) so more listening time

Operator determines maximum imaging depth

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21
Q

Acoustic Propagation Properties

A

Effects of medium upon sound wave
Propagation speed

Attenuation
Absorption
Reflection
Scattering

Impedance

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22
Q

Propagation speed

A

Determined by density and stiffness of medium

All sound travels at the same speed through same medium
Soft tissue (st)- 1.54 km/s (1.54 mm/s)
Lung< fat < soft tissue < bone
0.5, 1.45, 1.54, 3.0 km/sec respectively
Speed m/s = frequency (Hz) x wavelength (m)

know that fat and soft tissue are similar speed, but fat is slightly fas

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23
Q

Attenuation

A

Decrease in intensity and amplification in soft tissue

Greater frequency, greater attenuation

Limits maximum depth from which can obtain images

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24
Q

Absorption

A

Energy imparted to cell is lost by conversion to another form such as heat or vibration of intracellular particles

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25
Q

Reflection

A

Some of propagating acoustic energy is redirected back toward transducer

Smooth reflector (i.e. mirror) is specular reflector (e.g. diaphragm)

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26
Q
A

Specular reflector is the line around the kidney in this image, it disappears where the reflection doesnt bounce back to the transducer.

the inside of the kidney that is hyperechoic (lighter) is due to the collectiong ducts.

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27
Q

Scattering

A

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- dont need to know this name

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28
Q

Impedance

A

Acoustic resistance to sound as travels through medium
Intensity increases with decrease density and with increased propagation speed

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29
Q

Difficult to Image Media

A

Bone
Great reflector
Backscatter/reflection

High propagation speed
Increased impedance
Increased attenuation

Lung
Great scatter
Low propagation speed

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30
Q

Artifact Sources

A

Machine malfunctioning
Poor engineering
Acoustic artifacts
Operator error
Interpreter error- Anatomic artifact/pitfall

31
Q

Acoustic Artifact Types

A

Reverberation
Shadowing
Enhancement
Reflectors
Propagation speed
Resolution

32
Q

Acoustic Artifact Types

Reverberation

A

Multiple echos or reflection equally spaced
May occur when 2 strong reflectors lie in line of US beam

33
Q

Acoustic Artifact Types

Shadowing

gallstones in liver on left image prevent beam from going through resulting in large shadow
A

US cannot pass through first structure
either highly reflective or high attenuation or highly scattered

sound does not penetrate, so acoustic shadow as useful artifact:
renal calculi
cholelithiasis

34
Q

Acoustic Artifact Types

Enhancement

everything brighter on other side of fluid.
A

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

“opposite fo shadowing”

35
Q

Acoustic Artifact Types

Curved and Oblique reflectors

A

Image not present or understated
(see previous renal film/specular reflector)

36
Q

Acoustic Artifact Types

Propagation speed errors

A

If tissue is not 1.54 KM/sec, incorrect depth of image

37
Q

Acoustic Artifact Types

Resolution

A

Appears as 1, if closer than resolution of machine
Try to image in different plane to confirm

Note: any abnormal finding in any imaging discipline tries to see same in another orientation to “confirm”

38
Q

Quality Assurance

A

Tissue equivalent phantom
Cysts
Solids
Resolution
lateral and vertical

39
Q

Biological Effects & Safety Measures

A

Very high US intensity can cause damage
Thermal injury
Exams that cause <1 degree Centigrade elevation of temperature are considered safe
Exams that cause >41 degrees Centigrade temperature are harmful to fetus

40
Q

Safety issues

A

Cavitation
Bodies of gas, bubbles, cavities may be excited by US
May vibrate, shrink, expand
Could lead to tissue injury
Minimal evidence that this really occurs, but could in theory
Can at lithotripsy levels

Do not perform a scan without reason
Do not prolong a scan without reason
Use minimal output power to produce images

41
Q

Orientation to transabdominal approach films

A

Typical “outer” approach

Longitudinal
Head on L
Foot on R

Transverse
R
L

Cavity approach changes orientation

42
Q

Echogenicity

A

Presented white on black
More white, more echogenic
(Denser matter)
black, less echogenic
(Fluid)

Imaging choice for cystic vs. solid

43
Q

Cyst

A

“Black” fluid filled
Enhancement

44
Q

Abdominal studies

A

Transabdominal sonography (TAS)
Usually NPO
Decreases bowel gas
GB should be “full”
Same technique in chest wall cavity when looking for fluid
Pleural effusion
US guided tap

Common Abdominal Studies
GB and Biliary system
Pancreas- should not be visible, if it is its too mig
Kidneys
Spleen
Retroperitoneum

45
Q
A

Cholelithiasis

45
Q

GB and Biliary system

A

Liver, GB, CHD, CD, HA, PV
Cholecystitis
Cholelithiasis
Choledocholithiasis
GB polyps
Echogenic Bile

46
Q
A

Choledocholithiasis

47
Q
A

Cholecystitis-thick shaggy GB wall

48
Q

Pancreas

what can you see w US

A

Pseudocysts
Pancreatitis
Acute vs chronic
Tumors

Pancreas tricky to visualize when normal
Note classic structures
Aorta round- thicker wall
IVC “collapsed”-thinner wall
Fat around Superior Mesenteric Artery (SMA)
Splenic Vein (SV) courses opposite
Acute pancreatitis, swollen large, less echogenic
Chronic pancreatitis, increased echogenic damaged areas

49
Q
A
50
Q

Kidneys

A

Hydronephrosis
Parenchymal changes
CFR- small kidneys, more echogenic
Masses
Cysts
Congenital deformities
Adrenals- not usually visualized

Homogeneous parenchyma
Center is echogenic collecting system
NOT medulla vs cortex, its the parynchema vs collecting ducts

Usually less echogenic than liver
Liver aids visualization of Right
Spleen aids visualization of Left
But spleen normally smaller

51
Q

Hydronephrosis

A

Dilated collecting system in renal pelvis
Can have hydroureter as well

52
Q

Spleen

A

Enlargement
Infections
Hematopoietic disorders
WBC disorders

Rupture
Sickle cell
Neoplasms

spleen is Normally homogeneous

53
Q

Retroperitoneum

A

Enlarged lymph nodes
Masses
Aorta
Abscess

54
Q

AAA

A

Lumen walls
Lumen that blood flows through/clot

55
Q

High Resolution of Superficial Structures

A

Thyroid
Scrotum and Testes
Breast

56
Q

Thyroid

A

Normally homogeneous
True cysts
Malignant lesions
Multinodular goiter
Developmental cysts

Parathyroids are NOT usually visualized

57
Q

Scrotum and Testes

A

Normally homogeneous
Edema
Hydrocele
Orchitis and Epididymitis
Carcinoma
Seminoma
Varicocele

58
Q

Hydrocele

A

F= Fluid in scrotal sac

59
Q

Breast

A

Breast parenchyma fairly homogeneous
Masses
Cysts
Abscess

60
Q

Pelvic studies

A

Full urinary bladder for acoustic window
Urinary bladder
Pre and post void for volume/residual volume

61
Q

Prostate studies

A

Echogenicity usually homogeneous
Transrectal approach
Size
Masses

62
Q

Neonatal brain

A

Acousic window
Cartilage, not bone
Fontanelles
Why is this test not for an adult brain?

63
Q

Doppler shift

A

Change in frequency of sound as result of motion between sound and receiver
RBCs bouncing

Hz
Doppler shifts of -10 KHz to +10 KHz in Doppler studies
negative is away from transducer, dec frequency
positive is toward transducer, increased frequency

64
Q

Doppler

A

0 or 180 degrees - there is no image as the sound beam and motion are parallel
90 degrees, the velocity is 0, good for imaging
Motion mode for flow- graphic

65
Q

Aliasing

A

Artifact when flow appears negative but really positive
the deeper the sample volume (chosen by sonographer) the more likely aliasing
higher frequency, more likely aliasing
lower frequencies used more often

66
Q

Duplex studies

A

Images and Doppler in same study

67
Q

Color flow Doppler

A

Color is related to direction of flow in relation to transducer (positive/negative)
Many times this may correspond to venous vs. arterial flow

structures imaged B&W
Color added to vessels for flow/fxn
A pulsed US technique
Provides a range of resolution at expense of aliasing

68
Q

Echocardiography

A

Heart Imaging
motion mode and imaging modes
valvular abnormalities
wall motion analysis
ejection fraction
pericardial effusion

Need to image through “cardiac window”
Between bones

69
Q

Echo frequencies

A

highest frequency but smallest diameter transducers
Peds 3.5, 5.0, 7.5 MHz
diameters 3-6 mm
Adults 3.5, 2.25, 1.6 MHz
also a range of diameters
(transesophageal approach for even better resolution)

70
Q

FAST Ultrasound

A

Focused assessment with sonography for trauma (FAST) 4 areas:

(1) hepatorenal recess (Morison pouch)
(2) perisplenic area
(3) subxiphoid pericardial window
(4) suprapubic window (Douglas pouch)

https://www.ncbi.nlm.nih.gov/books/NBK470479/

71
Q

E-FAST US

A

extended FAST (E-FAST) add:
(1) bilateral hemithoraces
(2) upper anterior chest wall

https://emedicine.medscape.com/article/104363-overview#a2
https://www.saem.org/about-saem/academies-interest-groups-affiliates2/cdem/for-students/online-education/m3-curriculum/bedside-ultrasonagraphy/fast-exam

72
Q

US Take Home Points

A

Anatomical imagine, some function applications

Acoustic properties guide what “tissues” look like so don’t “see” same things as other imaging modalities

Sounds waves, not radiation, theoretical safety issues

Clin D III (11 decks)

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