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Flashcards in Overview of Diagnostic Imaging Deck (21)
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1
Q

Name four methods of diagnostic imaging

A

Radiography and computed tomography
Scintigraphy
MRI
Ultrasonography

2
Q

What is the physical basis of radiography/CT and what can these images show?

A

X-rays

Show variations in physical density

3
Q

What is the physical basis of scintigraphy and what can this show?

A

Gamma rays

Shows metabolic activity

4
Q

What is the physical bases for MRI and what can this show?

A

Radiowaves

Shows magnetization ?!!

5
Q

What is the physical basis for ultrasonography and what can this show?

A

High frequency sound

Shows echogenicity

6
Q

Define radiography

A

Making images representing a shadow of an object placed in an xray beam

7
Q

Which structures show as most radiopaque/radiolucent?

A

Opaque: Bone - Soft tissue and liquid - Fat - Air : Lucent

8
Q

How does CT differ from a standard radiograph?

A

Ring of xrays taken and amalgamated to make cross sectional slice - uaully looked at in the tranverse but can also look at sagittal plane and rebuild to make 3D image

9
Q

What is scintigraphy most often useful for?

A

Bone metabolism

10
Q

Where is diffuse uptake often noted in the normal anima;?

A

Growth plates and joints

11
Q

Why is scintigraphy useful?

A

More sensitive than radiographs for bony changes

12
Q

What is the main use of MRI?

A

Brain and spinal imaging

13
Q

How does MRI work?

A

Apply a pulsed magnetic energy and collecting radiowaves emitted by patient between pulses
Must be contained in a tunnel to allow a uniform magnetic field to form around the patient.

14
Q

How would a heamotoma appear on MRI?

A

Heterogenous

15
Q

How are colour changes on MRI referred to?

A

“Signal”
- An “Abnormal signal”
Fat has a “bright signal”

16
Q

What form of radiography may be useful for observing dynamic processes?

A

C arm radiography

Allows real time moving xray

17
Q

How does ultrasonography work?

A

Fire pulses of high frequency sound and collect returning echos

18
Q

How are images of ultrasound described?

A

Hypo or hyper echoic

19
Q

How do liver and spleen appear relative to each other on ultrasound

A

Spleen is hyperechoic (brighter)

20
Q

How do bladder and prostate appear differnet on ultrasound?

A

NB: Would appear the same on radiogrpah

Bladder is hypo-echoic due to urine

21
Q

When is diagnostic imaging most likely to be useful?

A

Structural lesions of a system rather than a dysfuntion