MSK/Rheumatolgy - Radiology - Exam 3 Flashcards
What is the first line choice of imaging for all MSK complains?
Plain radiography (x-ray)
On a radiograph, what appears black and what appears white?
Black - air
White - bone
What are indications for radiography?
First line and usually order before advanced imaging
Fractures
Dislocations
What are radiograph contraindications?
Exclusively soft tissue injuries
Caution with excessive repeat images and unnecessary radiation
What are advantages for radiography?
Readily available Reproducible Inexpensive Patient ease Technical training not required
What are limitations for radiography?
Superimposed structures (3D data on a 2D image)
Radiation exposure
Low sensitivity for subtly fractures and soft tissue injuries
What imaging technique produces tomographic images to put data into sections to create a 3D image?
Computed Tomography (CT)
What are indications for a CT?
Combined with contrast to image joints Stereotactic frame (biopsies, surgical planning) Angiography Small intraarticular fragments
What are CT limitations?
Unnecessary imaging Significant metal in area to be imaged Allergy to contrast dye Pregnancy Claustrophobia
What are advantages to CT imaging?
Tomography
Best bone assessment modality
Higher contrast resolution (iodine based)
What are limitations to CT imaging?
Artifacts (blurring from pt movement, beam hardening) Limited use for soft tissue Weight limitations, 300-400lbs Cost (higher than X-ray lower than MRI) Radiation exposure
How do you interpret a CT image?
R side of pt is on the L side of the screen
Axial images: looking from the pts feet toward the head
Coronal: patient is facing you
Sagittarius: looking from the side
What plane divides superior and inferior?
Axial
What plane divides anterior and posterior planes?
Coronal
What divides right and left planes?
Sagittal
What type of imagining utilized a strong magnetic field with radio frequency pluses and collects differences in tissue signal intensities?
Magnetic Resonance Imaging (MRI)
What are advantages to MRIs?
Superior contrast resolution
Ideal for soft tissue pathology while still good for bone pathology
Highly sensitive
Contrast compounds generally safer than CT contrast medium (gadolinium based)
What are MRI limitations?
Magnetic field Large shielded imaging site Claustrophobia Expensive One exam = one body part Takes an average of 45min
What are indications for an MRI?
Intraarticular soft tissue structures
MR arthrography
Superior sensitivity in the diagnosis of early detection of bone marrow conditions, stress fractures, osteomyelitis, and malignancy
Problem solver tool instead of initial screening tool
What test has the most radiation?
CT
What test has the least radiation?
MRI and ultra sound
What are contraindications of MRIs?
Pacemakers
Mechanical pumps
Electronic stimulators
Metal products
What type of MRI is better for anatomical assessment? And how does it present?
T1
Fat is bright and typically fluid is dark (gadolinium)
What type of MRI is better for fluid assessment? And how does it present?
T2
Fat/fluid are both bright (adding fat saturation a,lows for fat to be dark)
Highlights soft tissue injuries
What type of imaging transmits sound waves and detects reflected sound waves to produce a tomographic image?
Ultrasound
What is echogenicity?
Frequency of sound waves
Low- cystic
High- solid mass
What does a Doppler measure?
Motion
What are advantages to ultrasound?
Beneficial for soft tissues (tendons and muscles) Low cost No known harmful effects Highly portable Unossified epiphyses
What are limitations to ultrasound?
Artifacts
Limited skills by provider
Minimal use in evaluating bone
What are indications of ultrasound?
Common study of choice for infants
Soft tissue conditions
Guided assistance for joint injections, biopsies, soft tissue drainage
What are contraindications of ultrasound?
None
What is a bone scintigraphy?
Nuclear medicine imaging bone scan
IV injection of radioisotope bound to phosphate (tracer)
Imaging may be completed at different phases between 1min and 24 hours following injections
Tracer distributes in metabolically active bone at 2-4 hrs
Produces single or cross sectional projection
What are advantages to bone scans?
Very sensitive for skeletal pathology
Negative = negative
Mildly sensitive for soft tissues
What are limitations to bone scans?
Non specific
Lack detail
Lower sensitivity in early fractures with slow healing potential
Radiation exposure
What are the 3 types of complete fractures?
Transverse
Oblique
Spiral
What are the 3 types of incomplete fractures?
Greenstick
Torus
Bowing
What is a comminuated fracture?
Fracture resulting in many bone pieces
What is an avulsion fracture?
Injury to the bone where a tendon or ligament attaches
What is an impact fracture?
Occurs when the broken ends of the bone are jammed together by the force of the injury
What is a fissure fracture?
Only the outer layer of the bone is broken
What is a greenstick fracture?
Fracture in which one side of the bone is broken and the other only bent (break doesn’t go all the way through)
What is a torus fracture?
Occurs when a bone slightly crushes in on itself
Why do pediatric fractures typically heal faster?
The periosteum covering the bones is more metabolically active, thicker, and more durable
What are apophyseal injuries?
Fracture occurring in adolescents that separates the growth plate (apophysis) of a bone from the main osseous tissue at a point of strong tendinous or ligamentous attachment
What is the Salter-Harris Classification system?
Severity classification of fractures involving the physeal (growth plate)
What is a type I Salter-Harris fracture?
Physis only
least severe
What is a type II Salter-Harris fracture?
Metaphysis and physis
What is a type III Salter-Harris fracture?
Physis and epiphysis
What is a type IV Salter-Harris fracture?
Metaphysis, physis, and epiphysis
What is a type V Salter-Harris fracture?
Physis only; crushing injury
most severe
What type of physis fracture is most common?
Type II (metaphysis and physis)
Are are concerning features of bone tumors and lesions?
Indistinct margins Abnormal periosteal reaction Soft tissue mass Rapid growth Pathologic fracture
What are the 5 types of displacements?
Translation Angulation Rotation Shortening Distraction
What is a translation displacement?
Sideways motion of the fracture, usually described as a percentage of movement
What is an angulation displacement?
The normal axis of the bone has been altered such that the distal portion of the bone points off in a different direction, usually measured in degrees
What is a rotational displacement?
Rotation of the distal fracture fragment in relation to the proximal portion
What is a shortening displacement?
Shortening is the amount a fracture is collapsed, measured in cm of overlap. Also called a bayonete apposition
What is a distraction displacement?
Fracture resulting in increased bone length due to widening of the compartment between the broken bones (basically the opposite of an impaction/compression)
What is an occult fracture?
Does not appear well on an X-ray “hidden”
