Lecture 3: Diagnostic Imaging Overview Flashcards Preview

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Flashcards in Lecture 3: Diagnostic Imaging Overview Deck (45)
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1
Q

Which imaging modality uses high frequency sound waves to generate an image?

A

Ultrasound

2
Q

What are the pros and cons of using ultrasound?

A
  • Pros = no radiation, cheaper, and non-invasive
  • Cons = bowel gas and lung tissue hinder US image; dependence of skills of techni
3
Q

What is a FAST exam for diagnostic imaging and it’s primary views or windows?

A
  • Focused Assessment w/ Sonography in Trauma
  • Subxiphoid
  • RUQ
  • LUQ
  • Suprapubic
4
Q

A FAST exam diagnostic study is used to assess for what?

A

Free fluid in body

5
Q

What are the 5 radiographic densities and how do each appear?

A
  1. Metal - BRIGHT WHITE
  2. Air - BLACK
  3. Soft tissue - LIGHT GRAY
  4. Fat - DARK GRAY
  5. Mineral - OFF WHITE
6
Q

What are the 2 GI contrasts that can be used with X-ray?

A
  1. Barium
  2. Gastrograffin
7
Q

After giving contrast to patient for XR, how long should you wait for best visualization?

A

45 mins s/p ingestion

8
Q

Move to what type of XR has decreased costs?

A

Digital XR

9
Q

What are the cons of using XR for imaging?

A
  • 2D pic
  • Radiation exposure
  • Poor detail of soft tissue
10
Q

Which imaging modality is used for mammograms and line/tube placement?

A

XR

11
Q

How does fluoroscopy imaging work?

Allows for what type of imaging?

A

Uses continually emitted x-rays and allows for real-time visualization

12
Q

How do the images and radiation exposure differ btw fluoroscopy and XR?

A
  • Images are intensified = decreased radiation exposure
  • Images are attenuated differently than XR
13
Q

What are 6 uses for Fluoroscopy?

A
  1. Esophagram
  2. Upper GI study
  3. Small bowel follow-thru
  4. Barium enema
  5. Cardiac
  6. Vascular
14
Q

What are 3 cons associated with using CT imaging?

A
  • Potential contrast rxn
  • Exposure to radiation
  • Diagnosis limitations
15
Q

What type of contrast is used with CT scans?

A

IV iodinated

16
Q

What are the best uses of contrast with CT?

A
  • Vessels
  • Visualize tissue changes
  • Urinary tract
  • Fallopian tubes
17
Q

Any suspicion of what 3 complications should make you think about using contrast with a CT?

A
  • Bleed
  • Renal stone
  • Retroperitoneal hematoma
18
Q

Neuro contrast with CT is good for visualizing what?

A
  • Veno/angiogram
  • Abscess
  • Malignancy
19
Q

One of the strengths of using MRI is that it provides greater detail of what structures?

A

Soft tissues

20
Q

MRI uses a magnetic field to manipulate what?

A

Polarity of H+ ions

21
Q

In regards to T1 vs. T2 weighted MRI images which has a higher signal intensity of water and is therefore more suitable for visualizing pathology?

A

T2

22
Q

In regards to T1 vs. T2 weighted MRI images which gives better views of normal anatom (anatomical details, fat containing structures, subacute hemorrhages)?

A

T1

23
Q

When using MRI what are 4 patient situations you must be aware of and take precaution to?

A
  • Cardiovascular devices = pacemakers, stents, mechanical valves, IVC filters
  • Unstable pts
  • Claustrophobic and agitated pts
  • Large body habitus
24
Q

What is the preferred type of contrast used with MRI?

A

Gadolinium

25
Q

Using gadolinium with T1-weighted MRI improves the visibility of what?

A
  • Inflammation
  • Tumors
  • Blood vessels and some organs
  • Blood supply
26
Q

Nephrogenic systemic fibrosis is a possible adverse effect associated with what contrast agent?

A

Gadolinium

27
Q

Although generally well tolerated, what are some of the risks associated with the use of gadolinium as a contrast agent?

Especially in which pt populations?

A
  • Contrast induced nephropathy
  • Nephrogenic systemic fibrosis
  • Advanced renal failure or dialysis pt (GFR <30 mL)
28
Q

When is the onset of nephrogenic systemic fibrosis following gandolinium exposure?

Signs/Sx’s?

A
  • Onset: 2 days - 18 weeks s/p exposure!
  • Sx: thickening and hardening of skin. Spares head. Mimics scleroderma!
  • Stiffen extremities involved, flexion contractures
29
Q

What are the pros associated with using MRI?

A
  • Safe
  • NO radiation
  • Extremely precise w/ incredible soft tissue detail
30
Q

What are 4 cons associated with using MRI?

A
  • Not widely available
  • Costly
  • Body habitus
  • Pts must have extreme patience (30-90 mins)
31
Q

What are 3 systems that MRI is used for?

A
  • Neuro
  • MSK
  • Repro
32
Q

Which type of imaging modality uses the injection of contrast media directly into artery or vein via needle or catheter?

A

Angiography

33
Q

What 3 systems is angiography utilized in?

A
  • Neuro
  • Pulmonary
  • Cardiovascular
34
Q

What are 3 deterministic effects (acute) associated with ionizing radiation exposure?

A
  • Burns
  • Sterility
  • Radiation sickness
35
Q

What are 2 stochastic effects (chronic) associated with ionizing radiation exposure?

A
  • Cancer
  • Hereditary
36
Q

Which patient populations are at greatest risk from ionizing radiation exposure?

A
  • Children
  • Young adults
  • Women of repro. age (always get urine β-hCG)
37
Q

The cells most sensitive to radiation damage have what 3 characteristics?

A
  • Rapidly dividing
  • Undifferentiated
  • Have a long mitotic figure
38
Q

What 4 imaging modalities use ionizing radiation?

A
  1. Radiograph (XR)
  2. CT
  3. Fluoroscopy
  4. Nuclear medicine
39
Q

Contrast is used with medical imaging to increase the differences in?

A

Density between anatomic structures

40
Q

Special consideration for using contrast and radiation imaging techiques should be taken in renal patients with what serum Cr?

A

Cr ≥ 1.5

41
Q

Which days during pregnancy are considered critical and should be considered when selecting an imaging modality with contrast or radiation?

A

Days 16-45!

42
Q

Special consideration while using contrast and radiation imaging modalities need to be taken in pts on what medication?

Need to beware of what?

A

Metformin –> beware of lactic acidosis

43
Q

What are the signs/sx’s of hypersensitivity rxns to contrast agents?

A

Hives, anaphylaxis, urticaria, pruritus, and angioedema

44
Q

What are the signs/sx’s of chemotoxic rxns to contrast agents?

A

Self limited: N/V and flushing

45
Q

What are the signs/sx’s of vasovagal rxns to contrast agents?

A
  • Increased vasovagal tone
  • ↑ vagal tone -> ↓ SA and AV node conduction = bradycardia w/ vasodilation