Imaging and modalities Flashcards
Radiography (plain x-rays)
noninvasive imaging used to identify and screen for bone and joint injuries, lung or heart disease, foreign objects, etc
use ABCS to interpret:
- Alignment with adjacent bones, contours
- Bone density and texture of bone (>density=whiter)
- Cartilage spaces: joint space width, presence of subchondral bone, epiphyseal plates
Advantages: convenient, inexpensive, quick
Disadvantages: exposure to ionizing radiation, poor for visualizing subtle fractures and soft tissue injuries
Magnetic resonance imaging (MRI)
T1 vs. T2
noninvasive test used to provide visualization of soft tissues; uses magnetic fields rather than radiation
sectional images can be configured into 3D
utilizes 2 types of images:
- T1 demos fat within the tissues and typically used to asses bony anatomy
- T2 suppresses fat and demos tissues with high water content; used to assess soft tissue structures
Advantages: high quality imaging of almost any body structure
Disadvantages: relatively expensive, time-consuming, can’t be used if patient has any implanted metal device, claustrophobic environment
Computed tomography (CT) or CAT scan
noninvasive test that provides sectional imaging of bone and most soft tissues
used plain film lives that are enhanced y a computer to improve evolution; multiplayer so can image in any plane
especially useful for chest and abdomen
typically used to assess complex fractures as well as facet dysfunction, disc disease or spinal stenosis
Advantages: fast; provides high quality imaging of bone, soft tissue and blood vessels all at the same time
Disadvantages: large amounts of radiation; not as high quality as MRI for soft tissues; relatively expensive.
Bone scan or bone scintigraphy
uses a radio nucleotide injected intravenously to visualize areas of increased metabolic activity in bone (remodeling)- isotope settles in areas of high activity (“hot spots”)
helpful for identifying stress fractures and tumors that are not detected by x-ray; also used for RA, bone cancer, bone infection
Advantages: small amounts of radiation; ability to visualize metabolic activity in bone
Disadvantages: slow procedure (1 hour scan + time for contrast to circulate after injection); potential adverse reaction to contrast
Angiography
an invasive procedure in which a catheter and contrast material are used in conjunction with x-rays, CT or MRI to visualize blood vessels throughout the body
Arthrography
radiography of a joint after injection of opaque contrast material
typically used to identify abnormalities within joints (tendon ruptures)
expensive and carries invasive risks
Bone density scan or dual energy x-ray absorptiometry (DEXA)
gold standard for measuring bone mineral density
delineates osteopenia from osteoporosis
Diagnostic Ultrasound
clinically convenient, noninvasive procedure for helping diagnose partial tendon tears, soft tissue lesions, and swelling.
Utilizes transmission of high frequency sound waves; limited by contrast resolution, small viewing field, depth penetration and poor penetration of bone. Interpretation of data is subjective, so results depend on operator skill.
Can also be used as biofeedback to facilitate muscle activation (rehab US)
Positron emission tomography (PET) scan
used to detect non perfusing areas of the heart or to evaluate the brain in suspected cases of dementia, stroke, seizures and tumors.
discography
radipaque dye is injected into the disc to identify abnormalities within the disc (annulus or nucleus). The needle is inserted into the disc with the assistance of radiography (fluoroscopy).
not commonly used. requires high level of skill and proper equipment.
Fairly specific technique to identify internal disc disruptions of the nucleus and/or annulus
expensive, may be painful, and risk of infection since invasive
myelography
invasive technique using water-soluble dye. Dye is visualized as it passes through vertebral canal to observe anatomy within region.
rarely used due to side effects vs. MRI or CT scan; very expensive
traditionally used for discs and stenosis
