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

Name four methods of diagnostic imaging

Radiography and computed tomography
Scintigraphy
MRI
Ultrasonography

2

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

X-rays
Show variations in physical density

3

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

Gamma rays
Shows metabolic activity

4

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

Radiowaves
Shows magnetization ?!!

5

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

High frequency sound
Shows echogenicity

6

Define radiography

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

7

Which structures show as most radiopaque/radiolucent?

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

8

How does CT differ from a standard radiograph?

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

What is scintigraphy most often useful for?

Bone metabolism

10

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

Growth plates and joints

11

Why is scintigraphy useful?

More sensitive than radiographs for bony changes

12

What is the main use of MRI?

Brain and spinal imaging

13

How does MRI work?

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

How would a heamotoma appear on MRI?

Heterogenous

15

How are colour changes on MRI referred to?

"Signal"
- An "Abnormal signal"
Fat has a "bright signal"

16

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

C arm radiography
Allows real time moving xray

17

How does ultrasonography work?

Fire pulses of high frequency sound and collect returning echos

18

How are images of ultrasound described?

Hypo or hyper echoic

19

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

Spleen is hyperechoic (brighter)

20

How do bladder and prostate appear differnet on ultrasound?

NB: Would appear the same on radiogrpah
Bladder is hypo-echoic due to urine

21

When is diagnostic imaging most likely to be useful?

Structural lesions of a system rather than a dysfuntion