Common Diagnostic Imaging Techniques Flashcards
What are X-Rays?
uses electromagnetic waves to produce images
X-ray passes through the body and is absorbed in different amounts by different tissues, depending on the density of tissue
Bone= better absorption= better image
What shows up as what on x-ray?
dense material shows up as white ==> bone and metal
Air in lungs = black
Fat and muscle = shades of gray
When are X-rays used?
Bones and teeth: fractures and infections, bone tumors, osteoporosis
Chest: lung infections, breast cancer, enlarged heart
Abdomen: swallowed items, digestive tract problems (barium contrast medium)
What is the ABCS approach of X-ray interpretation?
Assess the following:
Alignment and joint space
Bone texture
Cortices
Soft tissues
What are the risks involved with x-rays?
has been linked to cancers (large doses of radiation)
Safe for adult
Not safe for developing fetus
Children more sensitive to radiation then adults
What is Computerized Tomography (CT) Scan?
Combines a series of x-ray images taken from different angles and uses computer processing to create cross sectional images or “slices” of bones, vessels, or soft tissue inside your body.
They give off more radiation than x-ray
Why would CT scan be used?
diagnose muscle or bone disorder
Pinpoint location of infection, tumor or fracture
Guide procedures such as surgery, biopsy, and radiation therapy
Detect and monitor diseases and conditions such as cancer, heart disease, lung nodules and liver masses
Monitor the effectiveness of certain treatments, such as cancer treatment
Detect internal injuries and internal bleeding
What are the benefits of diagnostic ultrasound?
Safe! (no radiation, no biological effects)
Quick
Portable
Low cost
Able to be done over metal
Can be done dynamically
What is diagnostic ultrasound?
high frequency sound waves that bounce off of tissues and organs to create a multi-dimensional image (image dependent on depth of tissue)
Good at capturing soft tissues, muscles and ligaments
Done in conjunction with CT scan (gold standard for RC tears)
What are common MSK evals done with diagnostic ultrasound?
RC tears, RC tendinopathy, bursitis, subacromial impingement, long head of biceps pathology
Medial/lateral epicondylitis, distal biceps tear
De quarvein’s, UCL tear (thumb), ganglion cyst
Gluteal tendon tears, trochanteric bursitis
Quadriceps tendon tears, patellar tendinitis, medial patella plica syndrome, meniscal cyst, baker’s cyst
ATFL ligament and morton’s neuroma
What is magnetic resonance imaging (MRI)?
technique that uses magnetic field and radio waves to create detailed images of organs and tissues in the body
The magnetic field 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
Produces 3D images that can be looked at from different angles
Does not expose body to radiation
What do MRI’s for bones and joints help evaluate for?
joint abnormalities caused by traumatic or repetitive injuries such as torn cartilage or ligament
Disc abnormalities in the spine
Bone infections
Tumors of bones and soft tissues
What do MRI’s for brain and SC help evaluate for?
aneurysms of cerebral vessels
Disorders of the eye and inner ear
Multiple sclerosis
Spinal cord injuries
Stroke
Tumors
Brain injury from trauma
What do MRI’s for heart and blood vessels help evaluate for?
size and function of heart chambers
thickness and movement of the walls of the heart
extent of damage caused by heart attack or heart disease
structural problems in the aorta, such as aneurysms or dissections
inflammation or blockages in the blood vessels
What do MRI’s for internal organs help evaluate for?
Check for tumors or abnormalities of:
liver and bile ducts
Kidneys
Spleen
Pancreas
Uterus
Ovaries
Prostate
What are the absolute contraindications of MRI?
Cardiac implantable electronic device
Metal pieces
Drug infusion pumps
Artificial limb
Hearing aid
What are relative contraindications of MRI?
tattoos less than 6 weeks old
Shunts
Medication patch
Joint replacement or prosthesis
Pt unable to obey breathing instructions or has severe claustrophobia
BMI (unable to fit in narrow machine)
What are open MRI?
larger opening
image quality is directly proportional to magnetic field strength
Open MRI pictures have less diagnostic information (Normal MRI magnetic field strength is 1.5-2 Tesla, Open MRI is less than .5 Tesla)
What is the difference between T1 and T2 MRIs?
T1 and T2 are developed by the different effects the magnetic fields have on the protons in the tissues
Signals in MRI are high or low (bright or dark), depending on pulse sequence used and type of tissue in the area of interest
Weighting the images to T1 or T2 will make different structures more apparent
How does CSF/Fluid show up on T1-weighted versus T2-weighted?
T1: Dark
T2: Bright (white)
How does inflammation (edema, infarction, demyelination) show up on T1-weighted versus T2-weighted?
T1: dark
T2: bright
What is the DEXA scan: bone density test?
dual energy X-ray absorptiometry
goal: designed to measure density of body tissue, does not produce high quality picture
Measures mineral content of the bones in certain areas of the skeleton
Measures bone loss as you age
Uses low levels of x-ray to measure how dense your bones are
Commonly used to diagnose OA
Compares your BMD and normal for age
What are bone scans?
used to detect stress fracture of the long bones and vertebrae, degenerative disease, infections, or tumor of bone
to look at bone metabolism
injection of isotopes several hours before scan to show increased areas of increased activity
X-rays do not show stress fractures unless 30-50% bone loss
Shows disturbance but does not define nature of the disturbance
Abnormal when scan shows darker “hot spots” or lighter cold spots
What is a bone scan used for?
arthritis
avascular necrosis
bone cancers
fractures
fibrous dysplasia
paget’s disease
infections involving bone