Session 2: Intro Medical imaging Flashcards
Describe the fundamental principles of how an x-ray works:
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.
Explain the advantages and disadvantges of x-rays
Describe fundamental principles of Fluoroscopy:
Involves x-rays; technique provides moving projection radiographs.
Angiography is the use of flurorscopy to view the cardiovascular system.
Explain advantages and disadvantages of using fluoroscopy:
Describe the fundamental priniciples of how computerised tomography scanning works:
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.
Whats the typical view from a CT image?
Explain the advantages and disadvantages of CT scans:
Disadvantages: Lower contrast resolution than MRI
Artefacts include metals.
Describe the fundamental priniciples of how Magnetic resonance imaging (or NMR) works:
Excellant soft tissue contrast is achieveable with MRI
Explain “MRI weighting”
Explain the advantages and disadvantages of using MRI
Good contrast resolution (can see between densities well)
Describe the fundamental priniciples of how positron emission tomography works
positron-emitting radionuclide (e.g. fluorine -18) introduced into body, bound to radioactive tracer (glucose)
Tumours very metabolically active
Explain the advantages and disadvantages of using PET scans:
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),
Describe the fundamental prinicples of how Ultrasound works:
Explain the advantgaes and disadvantages of using a Ultrasound scan:
Clinical example of using X-rays:
Chest-Infection, pneumothorax, trauma, effusion, oedema
Bowel- Dilatation, perforation
Orthopaedic- Is there a fracture, trauma
Post-Procedure- Nasogastric Tube, Pacemaker, PICC
Dentist
Clinical examples of using ultrasound:
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
Clinical example of using MRI scans:
CNS Brain and spinal cord; Brain tumour detection
Bones and Joint
Heart and Blood Vessels
Internal Organs
Gallstones detection
Clinical example of using CT scans:
MANY!
Diagnosis; Cancer, stroke, bony injury, blood flow.
Guide Further Tests or Treatment Radiotherapy, biopsy.
Monitor Conditions;Cancer treatment
Clinical example of using PET
Images can show rapidly growing tissue like in tumours, metastasis or infection.
Clinical example of using Fluoroscopy:
Angiography (view cardiovascular system)
Contrast GI Studies
Therapeutic Joint Injections
Arthrograms
Screening in Theatre
What are the anatomical planes?
What are the anatomical directions?
Give an introductory outline on the field of radiology, what are its uses and its limitations
Radiology is the science of medical imaging used to diagnose and sometimes also treat diseases within the body using ionising radiation.
Define nuclear medicine and its uses and limitations
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
Provide an explanation of what contrast media are, what are available and their common uses in radiology
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
Explain the concept of interventional radiology and provide a suitable clinical example
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)
