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Moores Blue Boxes > Medical Imaging Techniques > Flashcards

Medical Imaging Techniques Flashcards

1
Q

Types of imaging

A 
Conventional radiology (x ray)
Computed tomography (CT)
Ultrasonography (US)
Magnetic Resonance imaging (MRI)
Nuclear medicine imaging
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2
Q

What is a plain field study

A

Conventional radiology in which special techniques such as contrast media have not been used

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3
Q

How does conventional radiology work

A

Highly penetrating dreams of x rays transilluminate the patient , showing tissues of different densities of mass as images of differening intensities (light and dark)on film monitor

X ray tube—>human—> detector behind human

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4
Q

What appears dense (white) and less dense (dark) on conventional radiology (x ray)

A

Compact bone absorbs or reflects more then
Spongy bone
Organ-transparent in between

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5
Q

Radiolucent

A

Less dense

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6
Q

Radioopaque

A

Dense

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7
Q

PA projection

A

X rays transvers from posterior to anterior (x ray tube is posterior and detector is anterior)

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8
Q

AP projection

A

Opposite

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9
Q

Conventional radiographs are all viewed for body, head trunk shoulder, arms and legs

A

Patient is facing you AP view

Patient left always your right

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10
Q

How do you view radiographs for wrist, hands, feet

A

As if looking at own wrists hands or feet

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11
Q

What do L and R mean on radiographs

A

Side placed closes to the film (detector) image is viewed from same direction beam was projected

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12
Q

What does the introduction of contrast media(radioopaque fluids such as iodine or barium) to conventional radiography cause

A

Study of luminal or vascular organs and potential or actual spaces-such as digestive tract, blood vessels, kidneys, synovial cavities, and the subarachnoid space-that are not visible with plain films

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13
Q

Why do we usually need two views at 90 degree angles

A

Each radiograph represents a 2d view of 3d structure
Structures that get beams overlap each other

Need 2 views to localize an abnormality

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14
Q

What is seen in computed tomography

A

Radiographic images of body that resemble transverse anatomical sections

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15
Q

How does CT work

A

X ray passes through the body as the x ray tube and detector rotate around the axis of the body. Multiple overlapping radial energy absorption’s are measured, recorded, and compared by a computer to determine the radio density of each volumetric pixel (vowel) of chosen body plane

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16
Q

In CT the computer maps the vowels into a ___ __ that is displayed on a monitor or print out

A

Planar image (slice

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17
Q

In a CT what is seen as light and dark

A

Light-bone treated absorption (transparent) white

Dark-little absorption

18
Q

How is an axial ct viewed

A

As if standing at patients feet -from inferior

19
Q

How are coronal ct images viewed

A

As if patient is facing you

20
Q

How are sagittal ct viewed

A

Standing at patients left side

21
Q

What is ultrasonography used for

A

Visualizesuperficial or deep structures in body by recording pulses of ultrasonic waves reflecting off the tissues

22
Q

Advantadge of ultrasonography

A

Cheap and transportable
Real time-can see things moving
Structures and flow in vessel

23
Q

How does ultrasonography work

A

Transducer in contact with skin generates high frequency sound waves that pass through the body and reflect off tissue interfaces between tissues of differing characteristics, such as soft tissue and bone . Echoes from the body reflect into the transducer and convert to electrical energy. The electrical signals are recorded and displayed on a monitor as a cross sectional image which can be viewed in real time and recorded as a single image or on videotape

24
Q

Doppler ultrasonography

A

Shifts in frequency between emitted ultrasonic waves and their echoes are used to measure the velocities of moving objects . Blood flow through vessels seen in color superimposed on a 2d cross sectional image

25
Q

What does scanning the pelvic viscera require for ultrasound

A

Fully distended bladder. The urine serves as an acoustical window, transmitting sound waves to and from the posteriorly placed pelvic viscera. Distended bladder also displaces gas filled intestinal loops out of the pelvis

26
Q

Why do transvaginal ultrasound

A

Permits positioning of transducer closer to the organ of interest and avoid fats and gas which absorb or reflect sound waves, whereas air conducts them poorly.

27
Q

Ultrasound used for lungs

A

No

28
Q

Does ultrasound use radiation

A

No

29
Q

MRI provides images of the body similar to those of CT scene but is better for ___ __ differentiation

A

Soft tissue

30
Q

How does MRI work

A

Person placed in scanner with a strong magnetic field, and the body is pulsed with radio waves. Signals subsequently emitted from the patients tissues are stored in a computer and reconstructed into various images of the body .

31
Q

For MRI, how can how can we control appearance of tissues to generate images

A

Controlling radio frequency pulses

32
Q

In MRI, free protons int he tissues that become aligned by the surrounding magnetic field are excited (flipped) with a radio wave pulse. As the proton lips back, minute but measurable energy signals are emitted. What emits stronger and weaker signals

A

More signals emitted by tissues that are high in proton density, such as fat and water
Weaker0less protons

33
Q

What do moving fluids appear as what on T1

A

Black

Even through proton dense, after flip they move out of field

34
Q

T2

A 
World was 2 
Water looks white t2 
Fat dark
Blood flow dar
Subacute blood bright
Cyst bright
Solid mass bright
35
Q

T1

A 
Fat bright 
Acute and chronic blood gray
Subacute blood bright
Cyst dark 
Solid mass dark
36
Q

MRI see real time?

A

Yea with fast scanners

37
Q

Nuclear medicine imaging

A

Infor about distribution or concentration of trace amounts of radioactive substances introduced into the body. Shows images of specific organs after IV injection of a small dose of radioactive material

38
Q

A radionucleotide is attached to a compound that is selectively taken up by an organ such as ___ fr bone scanning

A

technetium-99m

Tc-MDP

39
Q

Positron emission tomography

A

Uses cyclotron produced isotopes of extremely short half life that emit positrons
Examines the physiologic function of organs such as the brain on a dynamic basis

Images viewed as whole organ or cross section

40
Q

SPECT

A

Similar to PET but longer lasting tracers

Less costly but more time and have lower resolution

Moores Blue Boxes (15 decks)

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