Radiology Flashcards
What are some different imaging modalities?
- X-ray
- Computed Tomography (CT)
- Magnetic Resonance (MR)
- Ultrasound (U/S)
- Nuclear Medicine
What uses a single pulse of ionizing radiation?
X-ray
X-rays are good for viewing what? But bad at viewing what else?
Good: bones and airspaces
Bad: Soft tissues and overlapping structures
Five basic radiographic densities
- Air (darkest)
- Fat (less dark)
- Fluid/Blood/Soft tissue (gray)
- Bone (white)
- Metal/Contrast (most white)
What is a two- dimensional representation of a three-dimensional object ?
X-rays
X-ray views:
Anteroposterior (AP “front to back”)
- Used if patient is unable to stand or sit for a PA view
- Lower quality than PA view
- Back is placed next to the film
- Heart is magnified and borders are fuzzier
X-ray views:
Lateral (LAT “side view”)
- Usually taken in conjunction with a PA view
2. Allows viewing of structures behind the heart (mediastinum) and provides three-dimensional image
X-ray views:
Oblique (OBL)
- At an angle
2. Used mostly on the limbs
X-ray views:
Posteroanterior (PA “back to front”)
- Used in chest x-ray
- Object that is closer to the film has sharper borders
- Chest is placed next to the film thereby placing most of the important structures, such as heart and great vessels, closer to the film
- Heart size is minimally magnified and borders are sharp
What is similar to X-ray and uses multiple pulses or “shots” of ionizing radiation to capture an image?
Computed Tomography (CT)
Is the dose of radiation for CT scans high or low?
High
What is the gold standard for evaluating severe trauma and many intra abdominal diseases?
Computed Tomography (CT)
CT’s are good for viewing what?
Good: Bone, airspaces, some soft tissue and overlapping structures (especially abdomen and in trauma)
CT’s are bad for viewing what ?
Bad: some soft tissues (nerves, muscles, connective tissue), patients with retained metallic objects (causes artifacts)
What kind of image is produced from a CT ?
The images produced are a “slice” of the patient, similar to a slice of bread from a loaf of bread.
What is the combination of continuous patient and x-ray tube movement resulting in a spiral configuration?
Helical CT
What are some different CT views?
- Sagittal or Median
- Coronal
- Axial or Transverse or Cross-sectional
What uses electromagnetism and radio frequency properties, presents no exposure to ionizing radiation, but is time consuming?
Magnetic Resonance (MR)
Magnetic Resonance is good for viewing what?
Good for: Soft tissue (nerves, muscles, connective tissue, brain, joints)
Magnetic Resonance is bad for viewing what?
Bad for: people who cannot hold still or have ferrous metal in the body
What uses sound waves (similar to sonar) to produce an image?
Ultrasound (U/S)
- Operator dependent
- Image is a focused segment of the object
- Rapid and portable
Ultrasounds are good for viewing what?
Good for: determining fluid vs. solids, abdominopelvic imaging (gallbladder, kidneys, uterus, testis), assessing blood flow (doppler)
Ultrasounds are bad for viewing what?
Bad for: things under bones (chest) and air filled chambers, deep things
What are some different ultrasound views?
- Longitudinal (same as sagittal)
2. Transverse (same as axial)
In what kind of imaging is radiation detected and used to create and image showing the distribution of the radioactive agent within the body?
Nuclear imaging
What is nuclear medicine typically used for?
To detect stress fractures before being visible on x-ray
Nuclear medicine is good for viewing what? But bad at viewing what else?
Good for: detecting normal or abnormal physiologic processes
Bad for: showing less anatomic detail
Before Pre-read of a chest film, what must you confirm?
- Image is from the correct patient
- Image is from the correct date
- Image is the correct body part
- Image is the correct type
- Image has the number of views expected
- Check to see if any comparison films exist
How is technical adequacy assessed?
RIP Technique
R- Rotation
I- Inspiration
P- Penetration
RIP Technique
Rotation
- Look at the clavicles relative to the vertebral column
- Should be equally spaced
- If not aligned, structures will change in appearance which may mean abnormality
RIP Technique
Inspiration
- Look at the ribs
a. should be able to count 9-10 ribs b. posterior ribs are easier to see
RIP Technique
Penetration
- Should see the ribs through the heart
- Should barely see the spine through the heart
- Should see pulmonary vessel near the edges of the lungs (lungs shouldn’t be completely black)a. over-penetrated film
1. lung fields almost completely black
2. suggests pneumothoraxb. under-penetrated film
1. soft tissue structures are obscured
2. image appears bright suggesting consolidation (pneumonia)
Steps for reading a chest x-ray
- Do your pre-read
2. Assess the technical adequacy of the film (RIP)
Steps for reading a chest x-ray
- Conduct a systematic method (ABCDE)
A- Airway/Airspaces B- Bones/Soft Tissue C- Cardiac Shadow D- Diaphragm E- Everything else
Steps for reading a chest x-ray
- A- Airway/Airspace
- Follow trachea down
Steps for reading a chest x-ray
- A- Airway/Airspace
- Follow trachea down
a. Is it midline?
b. Is it patent? - Look at airspaces
a. Do the blood vessels go all the way to the edges?
b. Are there any patches of white suggesting infection, fluid, or foreign objects?
Steps for reading a chest x-ray
- B- Bones
- Look at the clavicles, ribs, pectoral girdle, spine
a. for alignment, lack of symmetry, fracture lines
Steps for reading a chest x-ray
- C- Cardiac Silhouette
- Transverse diameter of the silhouette should NOT exceed 50% of the transverse diameter of the thoracic cage, called cardiothoracic ratio (only PA film)
a. AP films magnify the heart
b. Shallow inspiration make the heart horizontal and larger
Cardiac borders (moguls)
- Upper right border: Superior Vena Cava
- Lower right border: Right Atrium
- Left border (from the top)
a. aortic arch
b. pulmonary arteries
c. left atrial appendage
d. left ventricle
Steps for reading a chest x-ray
- D- Diaphragm
- Should be dome-shaped
- Right hemidiaphragm is always higher than or same level as left
- Check the costophrenic (sulcus) which should be dark and have sharp points