Radiological Interpretation Flashcards

1
Q

Define contrast media

A

• Substances which are administered to the patient which are either more radiopaque or more radiolucent than the surrounding tissue.

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2
Q

How can contrast media improve radiographic imaging?

A

• Provide detail of organ size, shape, position, internal detail and sometimes function

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3
Q

Describe negative contrast (include examples and where it is most commonly used)

A

• Negative contrast media have a low physical density  low radiographic opacity
– Radiolucent appearance on radiographs
– e.g. air, gases
– Mostly used in the bladder and GI tract

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4
Q

Give 2 advantages of negative contrast use

A
  • Cheap, quick and convenient

* Relatively safe

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5
Q

Give three disadvantages of negative contrast studies

A
  • Poor mucosal detail if used alone
  • Air slowly eliminated from the body (may confuse later studies)
  • Theoretical risk of air embolus in blood stream (C02 is more soluble and therefore safer)
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6
Q

Describe positive contrast (include examples )

A

• Positive contrast media have a high atomic number  high radiographic opacity
– Radiopaque appearance on radiographs
– E.g. barium, meglumine diatrozoate, iohexol

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7
Q

Describe the use of barium sulphate as a contrast medium

A
  • Used for GI contrast studies

* Administer as suspension, paste or mixed with food

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8
Q

Give advantages of using barium sulphate as a contrast medium

A

• Advantages: Low toxicity, Inert, Excellent mucosal detail, May be therapeutic, Relatively cheap

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9
Q

Give disadvantages of using barium sulphate as a contrast medium

A

• Disadvantages: Care with aspiration (NOT under GA), Irritant if enters body cavities – care with suspected perforation

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10
Q

Describe the use of Water soluble iodine as a contrast medium (include types and where they are used)

A
  • Imaging of cardiovascular system, urinary tract, joints, salivary glands, tear ducts, fistulas/sinuses, gastrointestinal tract, myelography
  • Types:
  • Ionic: suitable for IV or direct administration (but NOT myleography) e.g. meglumine diatrozoate (can interfere with the nervous system)
  • Non-ionic: suitable for myelography and any other use – e.g. iohexol. Recommended for all applications as fewer side effects. Gastro-intestinal preparations – specifically for GI studies
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11
Q

Give an advantage of using water soluble iodine as a contrast medium

A

Versatile – can be injected IV or directly administered, Rapidly absorbed if leak into body cavities

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12
Q

Give disadvantages of using water soluble iodine as a contrast medium

A
  • Hyperosmolar (ionic)  unpleasant side effects if conscious (nausea, vomiting, etc.)
  • Irritant if injected perivascularly (ionic)
  • Large doses of iodine are toxic
  • Contra-indicated IV in hypovolaemia, hypotension and cardiac or severe renal failure (stabilise first)
  • Rarely may cause iodine-induced acute renal failure
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13
Q

Define Positive contrast cystography

A

– Positive contrast cystography (infusion of positive contrast into bladder)

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14
Q

Define Pheumocystography

A

– Pneumocystography (infusion of air into bladder)

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15
Q

Define double contrast cystography

A

– Double contrast cystography (infusion of positive contrast followed by air into bladder)

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16
Q

Why would you take a plain radiograph before completing a contrast one?

A
o	Assess adequate technique
o	Contrast media contra-indicated?
o	May give a diagnosis
o	Assess patient preparation
o	Decide on suitable technique
o	Compare with subsequent films
17
Q

Give 4 advantages of CT/MRI

A

o Avoid superimposition
o Superior contrast/soft tissue detail compared to radiography
o Superior to radiography and ultrasonography for some conditions
o Very useful for surgical planning (e.g. oncology)

18
Q

Give 4 disadvantages of CT/MRI

A

o Radiography and ultrasonography may be more efficient
o Long periods of restraint needed (particularly with MRI)
o Cost
o Availability

19
Q

Give three locations that can be imaged using CT

A

Nasal cavity
Middle ear
Thoracic and abdominal masses

20
Q

Give three locations that can be imaged using MRI

A

Nervous system
Middle Ear
Soft tissue masses e.g. in the brain

21
Q

Describe the purpose of a radiological report

A

• Sufficient to enable someone else to be able to look at the radiograph and understand what you are talking about, without you being present to point it out

22
Q

Describe the process of a radiological report

A
  • Focus on important points
  • Use Radiographic (Roentgen) signs for accurate descriptions
  • Structures considered normal should be mentioned to confirm they have been evaluated
  • All abnormalities listed and prioritised in terms of likely significance
  • Differential diagnoses ordered in terms of likelihood
  • Consider further diagnostic tests necessary
  • Follow the standard format
  • Be systematic and try not to jump to conclusions or miss out stages
  • Be succinct and concentrate on most significant information
23
Q

Describe a technical assessment of a radiograph

A

– Whole point of this is to decide if the image is good enough to use for diagnosis; so need to specify this!
– Comment on aspects which are poor enough to affect quality and interpretation (don’t be overly critical)

24
Q

Describe an image assessment of a radiograph

A

– Concentrate on the abnormalities - use Radiographic (Roentgen) signs to describe
– Don’t let your clinical suspicion affect your observations!!
– Comment briefly on normal anatomy
– If you are struggling to work out what is happening, start by simply describing what you see
– Beware the effect of superimposition (e.g. pulmonary blood vessels crossing ribs vs. lung nodules; kidney overlap vs. additional structure)
– How visible is the border of the structure being evaluated?

25
Q

Describe the conclusion of a radiological report

A

– Summarise all your observations from all the images before producing your differentials / diagnosis
– Diagnosis/differential diagnosis
– These should lead on from your conclusions
– List in order of likelihood
– Don’t include those that you can eliminate as a result of your study