Introduction To Radiology Flashcards
What are the different modalities in radiology?
1-X-rays or flat plate or radiograph or digital radiography, or computed radiography 2-Fluoroscopy 3-Nuclear medicine or Scintigraphy 4-Ultrasound or sonography 5-Computed tomography 6-Magnetic Resonance Imaging
What are x-rays?
A form of electromagnetic wave photons traveling at the speed of light
The shorter the wavelength the greater the energy
Can cause ionization with causes damage
The higher the dose the higher the health risk
What are the advantages of radiography?
Fast
Relatively inexpensive
Available everywhere
Demonstrates bone and metal very well
what are the disadvantages of radiography?
Radiation level (1/5) exposure Limited information for soft tissues Artifacts such as superimposed shadows, magnification, blurring due to patient motion
what is the term for something bright on a x-ray?
Radioopaque
Radiodense
High density
What is the term for something dark on an X-ray?
Radiolucent
Low density
What is fluoroscopy?
Continuous X-rays passed through the patient onto a fluoroscope
If radiography is a photograph, fluoroscopy is a movie
Exam is monitored on a video monitor then recorded on video or still images
Utilizes a contrast agent
What are the advantages of fluoroscopy?
Can see inside a bowel, bladder or other cavities
Real time visualization
Moderate expense
Can be used for interventional procedures
What are the disadvantages of fluoroscopy?
Can accumulate significant radiation exposure for patient and especially personnel (4/5)
Contrast agent maybe unpleasant (barium) or can cause allergy nausea
What are interventional procedures?
All the minimally invasive procedures performed by radiologists, surgeons and cardiologists using imaging guidance
Examples treating stroke, drainage procedures, stopping hemorrhage
What are the advantages of interventional procedures?
Both diagnostic as well as therapeutic
Minimally invasive compare and less expensive compare to open surgery
What are the disadvantages of interventional procedures?
Complications(hémorragie, pain, embolus)
Blood product exposure to personnel
Radiation (2/5)
What is nuclear medicine?
A radionuclide + a physiologic analog=radiopharmaceutical
Radiopharmaceutical usually given through IV but may be ingested, infused
Gamma rays project from radiopharmaceutical
Gamma camera detect rays and computer generates digital images
Examples:PET scan for metastasis, treadmill test of heart
What is the advantage of nuclear medicine?
Excellent at showing the functions of organs
What are the disadvantages of nuclear medicine?
Do not reveal organ anatomy in great detail
Expensive
Ionization radiation
What is the term for a revealed anatomy in nuclear medicine?
Increased uptake
Hot
Photons rich
What is the term for not revealed anatomy in nuclear medicine?
Decreased uptake
Cold
Photon poor
Photogenic
What is the term for a revealed anatomy in ultrasound?
A more revealed anatomy?
A less revealed anatomy ?
A not revealed anatomy?
Echoegenic
Hyperechoic
Hypoechoic
Anechoic
What are advantages in ultrasound?
Relatively inexpensive No ionization radiation Real time Gives both anatomic and dynamic information (fetal movements) No contrast agents needed Imaging in any plane
What are the disadvantages of ultrasound?
Hard to see deep structures
Difficult with obese or immobile patients
Cannot see well through bone or air
Looks like weather map to untrained eye
What is Computed tomography(CT)
X-ray tube and multiple detectors are revolved around the patient
Detector plates measure attenuation of radiation that pass through patient
Digital images are produced and displayed by computer
What is the term for something that is bright in CT?
Something that is dark?
High attenuation
Low attenuation
What are the advantages of CT?
Excellent cross-sectional anatomy
Rapid
Widely available
Tremendous radiographic density resolution
Excellent guidance for interventional procedures
What the disadvantages of CT?
Relatively costly
Cumbersome for the very ill
Ionization radiation(3/5)
Metal or bone artifact
What is magnetic resonance imaging (MRI)
Strong magnetic fields are used to align body protons
Radio waves are transmitted to the protons
Protons absorb the radio wave energy then resonate it back
Detected the processed and displayed by computer
What is the term for anatomy that appears bright on MRI?
Anatomy that appears dark?
High signal intensity
Low signal intensity
What are the advantages of MRI?
Excellent cross sectional anatomy No ionization radiation Images directly in any plane Non invasive vascular imaging Generally available
What are the disadvantages of MRI?
Costly
Contraindicated for some patients (pacemakers, défibrillations, claustrophobic patients)
Artifact from motion, metal
