Common imaging technique Flashcards
Dense material shows up as ____ on X-rays
white
what is considered to be dense material?
bone and metal
Air in lungs shows up as ___ on X-rays
Black
Fat and muscle shows up as ___ on X-rays
Shades of grey
When is X-ray used for bones and teeth?
Fractures and infections
Bone tumours
Osteoporosis
When is x-rays used for chest?
Lung infections/conditions (pneumonia)
Breast cancer
Enlarged heart
When is X-rays used for abdomen?
Swallowed items
Digestive tract problems
What is the ABCS approach of X-ray interpretation?
Alignment and joint space
Bone texture
Cortices
Soft tissues
What to look for in alignment and joint space?
Fracture/subluxation/dislocation
Narrowing due to cartilage loss, calcification, new bone formation
What to look for in bone texture?
Altered density or disruption
What to look for in cortices?
Trace around the bone as a step on the cortex may indicate fracture or other pathology
What to look for in soft tissues?
Swelling
Foreign bodies
Effusion
Risk considerations for X-ray
Small amount of radiation exposed to is safe
Safe for adults
Not safe for developing fetus
Children more sensitive to radiation then adults
CT scan stands for what
Computerized tomography
What is a CT scan?
Combines a series of X-ray images at different angles and makes it into slices of bones/vessels/soft tissues
Which of CT scan or X-ray gives more radiation?
CT scan
Why is CT scan used?
diagnose muscle or bone disorder
pinpoint location of infection, tumor, fracture
guide procedures such as surgery, biopsy, and radiation therapy
detect and monitor diseases and conditions
monitor the effectiveness of certain treatments (cancer ex)
detect internal injuries and internal bleeding
Purpose of the fluid injected into knee for CT scan
Allows radiologist to evaluate meniscus tear or chondromalacia patella
Why is diagnostic ultrasound safe?
No radiation/no biological effects
Physiology of ultrasound
High frequency sound waves that bounce off of tissue and organs to create a multi-dimensional image
What is the gold standard for RC tears?
Ultrasound and CT scan
Why is ultrasound not a good choice for ACL and PCL?
Too deep
Physiology of MRI
Technique that uses magnetic field and radio waves to create detailed images of organs and tissues in the body
Theory behind the magnetic field for MRI
Temporarily realigns hydrogen atoms in your body
Radio waves cause these aligned atoms to produce very faint signals, which are used to create cross-sectional MRI images
Does the MRI expose the patient to radiation?
NOPE
Gold standard for diagnosing soft tissues injuries
MRI (magnetic resonance imaging)
MRI for brain and spinal cord
Aneurysms of cerebral vessels
Disorders of the eye and inner ear
Multiple sclerosis
Spinal cord injuries
Stroke
Tumors
Brain injury from trauma
MRI for heart and blood vessels
Size and function of the heart’s chambers
Thickness and movement of the walls of the heart
The extent of damage caused by heart attack or heart disease
Structural problems in the aorta
Inflammation or blockages in the blood vessels
MRI for internal organs
Check for tumors or abnormalities of:
liver/bile ducts/kidneys/spleen/pancreas/uterus/ovaries/prostate
Absolute contraindications of MRI
Cardiac implants
Metal pieces
Drug infusion pumps
Artificial limb
Hearing aid
Relative contraindications for MRI
Tattoos less than 6 weeks old
Shunts
Medication patch
Joint placement or prosthesis
Pt unable to obey breathing instructions or has severe claustrophobia
BMI (unable to fit in)
Normal MRI magnetic field strength is ___ Tesla vs Open MRI is less than ___ Tesla
1.5-2.0 vs 0.5
Which of T1 or T2 is better for inflammation?
T2
T1 vs T2-weighted - CSF/fluid
T1 = dark
T2 = bright (white)
T1 vs T2-weighted - muscle
T1 = grey
T2 = dark grey
T1 vs T2-weighted - Spinal cord
T1 = grey
T2 = light grey
T1 vs T2-weighted - Fat
T1 = bright
T2 = light
T1 vs T2-weighted - Disc (intact and hydrated)
T1 = grey
T2 = bright
T1 vs T2-weighted - Air
T1 = very dark
T2 = very dark
T1 vs T2-weighted - Inflammation
T1 = dark
T2 = bright
Most of common location of stress fractures?
Tibia
Goal of DEXA Scan
Measure density of bone tissue, does not produce high quality picture
How does DEXA works?
Uses low levels of x-ray to measure how dense your bones are
What is a bone scan used for?
Used to detect stress fracture of the long bones and vertebrae, DDD, infections and tumors of the bone
How does the bone scan work?
Injection of isotopes several hours before scan to show increased areas of increased activity
X-rays do not show stress fractures unless ___ of bone loss, while bone scans show at ___
30-50%
4-5%
What is a bone scan used for?
Arthritis
Avascular necrosis
Bone cancers
Fractures
Fibrous dysplasia
Paget’s disease
Infections involving bone
What is EMG used for?
As a diagnostic procedure to assess the health of muscles and the nerve cells that control them.
What does the EMG reveal?
Reveal nerve dysfunction, muscle dysfunction or problems with nerve to muscle signal transmission
Why get an EMG done?
Tingling
Numbness
Muscle weakness
Muscle pain/cramping
