Lecture 18 - Imaging Flashcards
How do radiographs create an image (basic)?
X ray beam passed towards a plate detector
Structures that absorb the x-rays appear more white
What are the advantages of radiographs?
Quick
Cheap
Readily available
Low ionising radiation dose
What are the downsides to radiographs?
Low contrast
2D images
How does Ultrasound create images (basic)?
Handheld prob using sound waves?
What are the advantages of using ultrasound?
Cheap
No ionising radiation
What are the disadvantages of ultrasound?
Operator dependant (need to be skilled)
Limited by bone (too dense to pass through)
What is ultrasound useful for imaging?
Thyroid
Superficial soft tissue
What are the advantages of CT?
Quick
Readily available
What is the disadvantage of CT?
High does radiation
What are the advantages of MRI?
The best contrast
No ionising radiation
What are the disadvantages of MRI?
Slow
Expensive
Limited availability
Claustrophobic
Cant be done if have metal in body
What are radiographs typically used for in Head N Neck?
Minor skull trauma (when cant do CT)
Cervical spine trauma
Foreign bodies in neck
What are ultrasounds typically used for?
Thyroid evaluation
Superficial head and neck masses
Superficial infection
Carotid Doppler
What are CTs typically used for for Head N Neck?
Trauma
Acute focal neurological symptoms
Malignancy
Infection (retropharyngeal infections can go to mediastinum)
Angiographic imaging of arteries and veins
When may you want to do a CT for an adult?
Any sign of basal skull fracture
Focal neurological deficit
Multiple vomiting episodes
What are MRIs typically used for?
Imaging brain since it’s good and seeing difference between white and grey matter (tumour evaluation, epilepsy)
Cervical spinal cord trauma
Head and neck tumours
What are the 3 planes of sectioning?
Coronal (wearing a crown)
Transverse(slice like a cucumber)
Sagittal (split down middle)
What are the normal lines between the skull bones called?
Sutures
What is it called when bone is eroded by soft tissue?
Lyric soft tissue
Go to the last slide and label skull 1:
1 = frontal bone
2 = sphenoid bones
3 = frontal sinus
4 = ethmoid bone
5 = nasal bone
6 = maxilla
7. = cribiform plate
8 = parietal bone
9 = temporal bone
10 = foramen magnum
11 = occipital bone
Go to the last slide and label sutures image 2:
1 = coronal suture
2 = lambdoid suture
3 = squamous suture
Go to the last slide and label image 3:
1 = coronal suture
2 = Sagittal suture
3 = lambdoid suture