Medical Imaging Flashcards

1
Q

What is radiology?

A

A branch of medicine concerned with the use of radiant energy or radioactive material in the diagnosis and treatment of disease

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2
Q

What is the difference between a radiologist and a radiographer?

A

A radiologist is a doctor who interprets images whereas a radiographer is someone who is trained to take the images

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3
Q

What is interventional radiography?

A

Medical sub-specialty of radiology utilising minimally-invasive image guided procedures

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4
Q

Give an example of invasive radiology

A

Angioplasty, insertion of a balloon into a vein or artery to widen it

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5
Q

How does an X-ray create an image?

A

When the beam passes through the human body, some of the X-rays are absorbed or scattered producing reduction of the beam

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6
Q

What is attenuation?

A

the reduction of the amplitude of a signal, electric current, or other oscillation

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7
Q

How does different tissues effect attenuation?

A

The higher density of tissue causes more attenuation so will show up as lighter grey or white on an X-ray

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8
Q

What are the five X-ray densities?

A
Air-Black
Fat-Dark grey
Soft tissue- Grey
Bone-Light grey
Metal-White
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9
Q

Why is it important to take images on multiple planes?

A

The fracture,break and dislocation may be hidden by one viewpoint

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10
Q

What is used to prevent radiation on certain body parts?

A

A metal screen, used primarily to stop radiation meeting the ovaries and testes

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11
Q

How would you take an image of a patient’s heart?

A

Posteriarly to avoid magnification of the heart

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12
Q

What is mammography?

A

Specific type of X-ray that uses low dosages which is designed for images of the breast

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13
Q

What is fluoroscopy?

A

Type of medical imaging that shows a continuous X-ray image on a monitor

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14
Q

When is fluoroscopy used?

A

When there is a need for real-time examination

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15
Q

Give an example of when fluoroscopy is appropriate

A

Implants during surgery, viewing movements of contrast agents

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16
Q

How does fluoroscopy differ from a regular X-ray?

A

The image is displayed on a fluorescent screen

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17
Q

What is angiography?

A

X-ray technique used in the examination of the arteries, veins and organs to diagnose blockages

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18
Q

What is the process of an angiograph?

A

A thin tube is inserted into an artery or vein, then a contrasting agent is injected to make the blood vessels visible on the X-ray image

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19
Q

What is tomography?

A

A method that produces images of single tissue plane

20
Q

What does CT stand for?

A

Computed tomography

21
Q

What does CAT stand for?

A

Computerized axial tomography

22
Q

What is a CAT scan?

A

Radiologic imaging that uses a computer to generate an image of the tissue density in a slice of the patient

23
Q

How should you envision yourself when seeing CAT scan?

A

The patient is on their back and your looking from their feet to their head

24
Q

What are the advantages of CAT scans?

A

Fast, readily available, good imaging of bony structures abdomen and lungs

25
Q

What are the disadvantages of a CAT scan?

A

High radiation dose, not so good at imaging soft tissue

26
Q

What is scintigraphy

A

Radioisotopes attached to drugs that travel to a specific organ or tissue are taken internally and the emitted gamma radiation is captured by external detectors to form two-dimensional images in a similar process to the capture of x-ray images

27
Q

What is the most commonly used radionuclide?

A

Technetium or 99mTc

28
Q

What does the term metastable mean and what does this allow?

A

The radionuclide atom has two basic energy states, as the atom transforms from the high-energy state to the low-energy state, it emits a quantum of energy in the form of a gamma ray

29
Q

What is single photon emission CT (SPECT)?

A

A scintigraphic technique whereby the the computer can detect subtle lesions overlain by other active structures

30
Q

How can a SPECT scan be improved?

A

Fusing it with a CT scan, this improves sensitivity and specificity

31
Q

What is a positron emission tomography (PET) scan?

A

A combination of computed tomography and scintillation

32
Q

How does a PET scan work?

A

An isotope is attached to a biological compound to form a radio-pharmaceutical, which is injected into the patient to from a 3D image

33
Q

What are the advantages of scintigraphy nuclear medicine?

A

Good functional information

Good localization of pathology

34
Q

What are the disadvantages of scintigraphy nuclear medicine?

A

High radiation dose

Not so good at differentiating between different pathologies

35
Q

What is a magnetic resonance imaging (MRI)?

A

A form of imaging that uses a powerful magnetic field and radiofrequencies to produce detailed images of the body’d internal structures

36
Q

How is the imaged created in an MRI?

A

When the radio signal is turned on, the energy is absorbed by different atoms is reflected back out of the body

37
Q

What are the three levels of signal intensity in a MRI?

A

High- white
Intermediate- grey
Low- black

38
Q

What are the two basic types of MRI images?

A

T1 and T2 weighted images

39
Q

Which type of MRI allows the image to see fat and water?

A

T2-weighted images

40
Q

Which type of MRI is better at identifying a tumour?

A

T2

41
Q

What are the advantages of MRI?

A

Gold standard of imaging

No radiation

Good localization of pathology

Good differentiation between pathologies

Excellent soft tissue imagine

42
Q

What are the disadvantages of MRI?

A

Strong magnet

Not so good showing anatomy of bones

Cost

Long duration of scanning

Need for anaesthesia in younger children/uncooperative patients

43
Q

Advantages of ultrasound?

A

Safe

No ionizing radiation

Relatively inexpensive

44
Q

Disadvantages of ultrasound?

A

Highly operator dependent

Structures surrounded by bone cannot be seen

Cannot be used for some tissues due to attenuation

45
Q

When should radiation be completely avoided?

A

In pregnant woman