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
Steps for reading a chest x-ray
- E- Everything else
- Look for gastric bubble (left side)
2. Check for EKG leads, lines, tubing, and other missed items( four corners of the film)
Reading a lateral chest film:
- Spine should appear brighter as it proceeds inferiorly
- Area behind the sternum (retrosternal) should be clear; contains upper lungs
- Area behind the heart (retrocardiac) should be clear; contains lower lungs
- Middle lobe projects over the cardiac silhouette
- Cardiac and diaphragmatic borders should be sharp
When to order imaging
- Should be used to confirm a suspicion
- Imaging should impact your treatment
* should not be a “just in case”. should not be a “fishing expedition”*
Common issues in primary care needing possible imaging
- Acute foot pain
- Acute ankle pain
- Acute knee pain
- Low back pain
- Headache
When is an ankle series indicated?
- Pt has pain in the “malleolar” zone AND
- Has bone tenderness at the posterior edge (6cm) of the lateral or medial malleolus OR
- Inability to bear weight both immediately after the injury and for four steps in the evaluation room
a. if the patient can transfer weight twice to each foot, the patient can
bear weight
b. is the patient limps, the patient can bear weight
*Ottawa rules
When is a foot series indicated?
- Pt has pain in the “midfoot” region AND
- Has bone tenderness at the base of the 5th metatarsal or the navicular OR
- Inability to bear weight both immediately after the injury and for four steps in
the evaluation room
a. If the patient can transfer weight twice to each foot, the patient can bear
weight
b. If the patient limps, the patient can bear weight
**Ottawa Rules
What would you suspect if initial x-rays came back normal?
Stress fractures
Bone scans can show abnormalities before x-ray findings in what?
stress fractures
consider CT or MRI
When is a knee series indicated?
- Old ass people above 55
- isolated tenderness to the patella ( with no other bony tenderness)
- Tenderness at the head of the fibula
- inability to flex the knee to 90 degrees
- inability to bear weight both immediately after the injury and for four steps in
the evaluation room. **(limping is allowed)
What are Ottawa knee rules used for ?
bony injuries
What imaging is preferred for knee injuries if you suspect a ligamentous injury?
MRI
If you suspect a bony fracture in the knee but plain radiographs are negative what imaging should you consider?
CT
Shoulder pain
- traumatic cause
- loss of range of motion
- presence of pain
Plain films of the shoulder will be able to identify what?
- Fractures
- Dislocations
- Arthritis
- Acromioclavicular (AC) joint or Sternoclavicular (SC) joint injuries
What imaging is preferred for labral, ligamentous, or rotator cuff injuries?
MRI
Hand series
If a fracture of the phalanx is suspected what kind of radiograph views are obtained?
- Anteroposterior (AP)
2. True lateral
Hand series
If the suspected fracture involves or is close to the joint what kind of radiograph view is used?
Oblique
Hand series
What kind of radiographic image is warranted when the fracture cannot be delineated because of superimposed digits, such as at the base of the proximal phalanx?
A radiograph of the entire hand
Hand series
All metacarpal fractures require what radiographic views?
- AP
- Lateral
- Oblique
Hand series
Suspected scaphoid fractures should be evaluated with what kind of series?
Scaphoid series
Anatomical sites for the phalanges and metacarpals
- head
- neck
- shaft
- base
What refers to fractures specifically involving the head of the distal phalanx?
Tuft fractures
What are the anatomical sites of scaphoid fractures?
- tubercle
- waist
- proximal pole
- distal pole
Hand series
What are fractures involving the joints?
Intra-articular fractures
Wrist
What views are used as part of the initial evaluation of patients with chronic wrist pain?
- Posteroanterior (PA)
- Lateral
- Oblique
What view of the wrist is used to evaluate the relative lengths of the radius and ulna?
PA view
Which radiograph is especially important for assessing carpal alignment?
Lateral radiograph
What views show the pisiform projected over the scaphoid tubercle?
True lateral views
A scapholunate angle greater than how many degrees suggests possible scapholunate instability?
Greater than 60 degrees
An angle of less than how many degrees suggests ulnar-sided wrist instability?
30 degrees
Additional wrist views to look for specific abnormalities include?
- scaphoid view (wrist in ulnar deviation) - scaphoid fractures
- Clenched fist view - scapholunate joint space widening seen with ligament disruptions
- Carpal tunnel view
- “hook” view to check for hook of the hamate fractures
- Osteoarthritis of the radiocarpal joint is characterized by narrowing of the joint space and sclerosis of the articular surfaces
What is a complex synovial joint formed by the articulations of the humerus, the radius, and the ulna?
The dam elbow
What are the three articulations of the elbow ?
- Radiohumeral
- Ulnohumeral
- Radioulnar
Radiohumeral
cappitellum of the humerus with the radial head
Ulnohumeral
trochlea of the humerus with the trochlear notch of the ulna
Radioulnar
radial head with the radial notch of the ulna (proximal radioulnar joint)
What fractures in the elbow are the most common?
Distal humerus or radial head fractures
What views are typical for radiographs of the elbow?
What view is typically used to visualize the radial head ?
- AP and Lateral
2. Oblique
Elbow
When a fracture is not seen but there is a clinical suspicion for it, what view can be performed?
Coyle’s view
Should presence of joint effusion in adults be treated as a fracture even if one cannot be identified?
Yes, should be treated as a non-displaced radial head fracture
In what view are elbow effusions seen best?
Lateral view
What is the sail sign?
an elevated anterior fat pad caused by elbow effusion
What is one of the most obvious soft tissue injuries and why?
Biceps tendon tear, obvious bulge of the retracted muscle
What group of people usually have injuries to the ulnar collateral ligament?
Baseball pitchers
What is lateral epicondylitis also known as?
Tennis elbow
What is the normal time span needed for imaging back pain without comorbid symptoms?
4-6 weeks
Imaging for back pain is not indicated in the first 4-6 weeks unless the back pain is present with:
- Progressive neurological findings or cauda equina symptoms
- Constitutional findings (fever, weight loss)
- Traumatic cause
- Current or history of malignancy
- Elderly
- Infectious risk (IV drug use, immunosuppression)
- Chronic steroid use
- Failed conservative management with signs of nerve root irritation
- At risk for osteoporosis
Back pain
X-ray
helpful for fractures or joint degeneration
Back pain
CT
preferred for serious trauma
Back pain
MRI
Imaging of choice for back pain with prior surgery, suspected infection, spinal
cord injury, tumor, or cord compression
Headache
CT
Preferred for trauma, to rule out hemorrhage, bone abnormalities, or prior to
lumbar punctures.
Headache
MRI
Preferred for soft tissue causes such as tumors, or vascular.
Common fractures
Oblique
has angulated fracture line
Common fractures
Transverse
runs perpendicular to the shaft of the bone
Common fractures
Spiral
has a multiplanar and complex fracture line
Common fractures
Overriding
one bone is displaced over the other
Common fractures
Distraction
fragments are separated by a gap
Common fractures
Torus
looks like a bump classified as incomplete fracture seen in children
Common fractures
Greenstick
fractures by bending like a green twig classified as incomplete fracture
seen in children.
Common fractures
Comminuted
have more than two fracture fragments