Radiology

Question 1

Why is the use of radiology to visualise body parts, tissues and organs useful for?

Answer 1

Clinical diagnosis
Treatment planning
Disease monitoring
Image guided intervention

Question 2

What is a Plain Radiograph?

Answer 2

The image produced by the passage of x-rays through an object

Question 3

How is a Plain Radiograph produced?

Answer 3

X-rays generated and projected towards the detector with the patient positioned in between

When X-rays hit the detector plate it turns black

X-rays are absorbed/attenuated most by the dense materials in a patient like bone and any metals

Question 4

What are the 4 main densities?
From most dense to least dense:

Answer 4

Bone
Soft tissue
Fat
Air

Question 5

What are the advantages of Radiographs/X-rays?

Answer 5

Are quick
Readily available
Cheap

Question 6

What are the disadvantages of Radiographs/X-rays?

Answer 6

Ionising radiation
Poor soft tissue contrast

Question 7

What are Radiographs useful for?

Answer 7

Imaging of skeletal trauma (Fractures or Joint dislocations)

Evaluating chronic bone or joint pathologies (osteoarthritis, rheumatoid arthritis, chronic osteomyelitis)

Question 8

What is articular cartilage?

Answer 8

The hyaline cartilage found at the ends of bones where joints are found

Question 9

On an x-ray, why does articular cartilage of joints appear black/dark?

Answer 9

Its less dense then bone so its more radiolucent
The darkness makes it look like there’s a joint space

Question 10

What is a fracture?

Answer 10

A complete or incomplete break in the continuity of the bone

Question 11

How do fractures appear on radiographs/X-rays?

Answer 11

Fracture ones/lucent dark lines on the radiograph

Question 12

What are the 6 types of fracture?

Answer 12

-Transverse
-Linear
-Oblique
-Spiral
-Greenstick
-Comminuted

Question 13

What is a transverse fracture?

Answer 13

Fracture which is horizontal/perpendicular to the bone

Question 14

What is a linear fracture?

Answer 14

Fracture which runs straight down the length of the bone/parallel to the bone

Question 15

What is an Oblique fracture?

Answer 15

Fracture that happens at an angle/diagonal

Question 16

What is a spiral fracture?

Answer 16

Fracture where the fracture line wraps around the bone in a spiral motion

Question 17

What is a Greenstick fracture?

Answer 17

Fracture where one side of the bone will snap but the other side of the bone is fin

Medullary cavity broken but cortical bone is in tact

Question 18

What is a comminuted fracture?

Answer 18

Fracture where there is multiple breaks in the bone

Question 19

How do the bones develop in childhood?

Answer 19

Start as cartilaginous model/template
Calcification begins as Chondrocytes begin to oldie
Perichondrium develops into periosteum
Osteoclasts begin to resorb the bone in the medullary region forming the medullary cavity where the bone marrow can form
This leaves cartilage remaining only at the ends of the bone

Question 20

Describe the structure of a long bone:

Answer 20

The epiphysis is the ends of the bone past the epiphyseal plate
Articular cartilage is found at the ends of long bones
The epiphyseal plate is a region of cartilage where bone growth occurs
Diaphysis is the shaft of the long bone
Metaphysics is the region between where the bone starts to widen and the epiphyseal plate

Question 21

How do bones visibly change on a radiograph during childhood?

Answer 21

Begin to become whiter from the middle of the cartilaginous model as it calcifies to bone
Ends of bone remain dark with cartilage

Question 22

What is a displaced fracture?

Answer 22

When the fractured bone is no linger aligned

Question 23

What is an undisplaced fracture?

Answer 23

Fracture where the bone is still aligned

Question 24

What are the 3 general stages to fracture healing?

Answer 24

1.) Inflammatory phase
2.) Reparative phase
3.) Remodelling phase

Question 25

What happens in the inflammatory phase of the fracture healing process? (hours to days)

Answer 25

Haemotoma forms (blood clot) Tissue dies Inflammation/cell proliferation begins

Question 26

What happens in the reparative phase of fracture healing? (days to weeks)

Answer 26

Angiogenesis (formation of new blood vessels) procallus forms Soft callous forms and is visible Hard callus forms

Question 27

What happens in the remodelling phase of fracture repair? (months to years)

Answer 27

The bone is remodelled by osteoblasts so that the fracture lie becomes completely obscured

Question 28

What is CT, what radiation does it use and how does it form an image?

Answer 28

Computerised tomography X-rays X-rays emitted from a detector that spins round in a circle very quickly, these are picked up by detectors producing many transverse images that are complied together to make a 3D image

Question 29

What are the advantages of CT scans?

Answer 29

Soft tissue detail better than plain radiographs/x-rays Quick to do Fractures seen much better in CT than plain radiographs Can produce 3D images

Question 30

What are the disadvantages of CT scanning?

Answer 30

Ionising radiation (higher than plain radiograph) Motion artefacts if patient moves Poor soft tissue detail compared to MRI but better than x-rays

Question 31

What is the units used to state the density of body tissues?

Answer 31

Hounsfield Units (HU)

Question 32

What colour does a structure with a very low HU appear and what about a structure with a high HU?

Answer 32

Very low is Black/dark Very high is white

Question 33

What is CT windowing?

Answer 33

When the CT image is manipulated so certain structures are highlighted

Question 34

What is MRI and how does it worK?

Answer 34

Magnetic Resonance Imaging Magnetic field causes H+ to align Radio pulse unaligned the H+ Radio pulse is then turned off and the time that it’s takes for the H+ to realign is measured and is used to form a cross sectional image

Question 35

What is MRI useful for imaging?

Answer 35

Bones, joins, ligaments and tendons is MSK MRI is better than CT and x-rays in assessment of soft tissue

Question 36

What are the advantages of MRI scranning?

Answer 36

Good for soft tissue structures Detailed anatomy of joints Excellent for bone marrow imaging

Question 37

What are the disadvantages of MRI scanning?

Answer 37

Scan takes a long time and patients have to be still Noisy Claustrophobic patients can’t tolerate Cant have patients with metallic or electronic devices like pacemakers

Question 38

What are the advantages of Ultrasound imaging?

Answer 38

No ionising radiation Excellent soft tissue resolution Can see fluid collections and superficial foreign bodies Dynamic imaging Good for image guided MSK intervention

Question 39

What are the disadvantages for Ultrasound imaging?

Answer 39

Operator dependant Poor deep tissue Limited bone and Intra articular imaging

Question 40

What is nuclear medicine?

Answer 40

When parts of the body are radioisotope labelled Biologically active drugs are given to the patient to serve as a marker of biological activity

Question 41

What areas are usually viewed with nuclear medicine?

Answer 41

Bone forming metastatic lesions Healing fractures Areas of osteomyelitis

Question 42

How do T1 weighted images differ to T2 weighted images?

Answer 42

T1 fat appears bright and fluid dark T2 fat bright and fluid bright