Session 2: Intro Medical imaging

Question 1

Describe the fundamental principles of how an x-ray works:

Answer 1

X-ray (high frequency) beam travels through body before striking a photographic plate and on film.

Not all x-rays reach the film. More dense (Higher AtomN), means greater attenuation (absorption/scattering) lighter on film.

Harder tissues analysis require high energy photon source.

Soft tissues analysis require less penertrating x-ray beams

Some too low energy x-rays not desirable; therefore x-ray filter used; hardening the beam.

Question 2

Explain the advantages and disadvantges of x-rays

Answer 2

Question 3

Describe fundamental principles of Fluoroscopy:

Answer 3

Involves x-rays; technique provides moving projection radiographs.

Angiography is the use of flurorscopy to view the cardiovascular system.

Question 4

Explain advantages and disadvantages of using fluoroscopy:

Answer 4

Question 5

Describe the fundamental priniciples of how computerised tomography scanning works:

Answer 5

CT scan, also known as a computed tomography scan, makes use of computer-processed combinations of many X-ray measurements taken from different angles to produce cross-sectional (tomographic) images (virtual “slices”) of specific areas of a scanned object, allowing the user to see inside the object without cutting it open.

Question 6

Whats the typical view from a CT image?

Answer 6

Question 7

Explain the advantages and disadvantages of CT scans:

Answer 7

Disadvantages: Lower contrast resolution than MRI

Artefacts include metals.

Question 8

Describe the fundamental priniciples of how Magnetic resonance imaging (or NMR) works:

Answer 8

Excellant soft tissue contrast is achieveable with MRI

Question 9

Explain “MRI weighting”

Answer 9

Question 10

Explain the advantages and disadvantages of using MRI

Answer 10

Good contrast resolution (can see between densities well)

Question 11

Describe the fundamental priniciples of how positron emission tomography works

Answer 11

positron-emitting radionuclide (e.g. fluorine -18) introduced into body, bound to radioactive tracer (glucose)

Tumours very metabolically active

Question 12

Explain the advantages and disadvantages of using PET scans:

Answer 12

Pros: Ease of use, performed on same equipment no need to move patient, highly sensitive and produces functional +anatomical information

Cons: ionising radiation (gamma rays),

Question 13

Describe the fundamental prinicples of how Ultrasound works:

Answer 13

Question 14

Explain the advantgaes and disadvantages of using a Ultrasound scan:

Answer 14

Question 15

Clinical example of using X-rays:

Answer 15

Chest-Infection, pneumothorax, trauma, effusion, oedema

Bowel- Dilatation, perforation
Orthopaedic- Is there a fracture, trauma
Post-Procedure- Nasogastric Tube, Pacemaker, PICC
Dentist

Question 16

Clinical examples of using ultrasound:

Answer 16

Solid Organs
Liver, kidneys, spleen, pancreas, thyroid, testes

Urinary Tract
Stones, dilation, volume

Obs and Gynae Pregnancy, uterus

Musculoskeletal

Use in Body Cavities
Transvaginal, transrectal , transoesophageal

Doppler capabilities to Assess blood flow; cardiovascular complications after surgery

Question 17

Clinical example of using MRI scans:

Answer 17

CNS Brain and spinal cord; Brain tumour detection

Bones and Joint

Heart and Blood Vessels

Internal Organs

Gallstones detection

Question 18

Clinical example of using CT scans:

Answer 18

MANY!

Diagnosis; Cancer, stroke, bony injury, blood flow.
Guide Further Tests or Treatment Radiotherapy, biopsy.
Monitor Conditions;Cancer treatment

Question 19

Clinical example of using PET

Answer 19

Images can show rapidly growing tissue like in tumours, metastasis or infection.

Question 20

Clinical example of using Fluoroscopy:

Answer 20

Angiography (view cardiovascular system)
Contrast GI Studies
Therapeutic Joint Injections
Arthrograms
Screening in Theatre

Question 21

What are the anatomical planes?

Answer 21

Question 22

What are the anatomical directions?

Answer 22

Question 23

Give an introductory outline on the field of radiology, what are its uses and its limitations

Answer 23

Radiology is the science of medical imaging used to diagnose and sometimes also treat diseases within the body using ionising radiation.

Question 24

Define nuclear medicine and its uses and limitations

Answer 24

Nuclear medicine imaging involves the administration of radiopharmaceuticals labelled with radioactive tracer into the patient. (radioactive tracers)

Typically PET scan used to pick up radiation emitted by tracer

Nuclear medicine images can be paired with CT scan taken simultaneously.

Uses: useful displaying physiological processes, detect monitor cancers, iodine concentrating ability of thyroid, blood flow to heart, excretion by kidney

Question 25

Provide an explanation of what contrast media are, what are available and their common uses in radiology

Answer 25

Used in Fluoroscopy/mri/ct/us; contrast media strongly absorb or scatter xrays, helps to better differientiate tissues and view dynamic processes better

BaSO4 used for evalution of GI tract. Iodine commonly used (intravenous).

Ideal: Low osmolarity, inert, safe, patient needs good kidney function

Question 26

Explain the concept of interventional radiology and provide a suitable clinical example

Answer 26

which minimally invasive procedures are performed using image guidance.

interventional radiology is to diagnose or treat pathologies, with the most minimally invasive technique possible.

E.g: By angioplasty (treating a blocked artery)