MSK Diagnostic imaging

Types of imaging? (7)

conventional radiology

contrast enhanced imaging

computerized tomography

magnetic resonance imaging

nuclear imaging

diagnostic ultrasound

fluoroscopy

what is a radiograph?

image of an anatomical part

what is an x-ray

invisible light beam

• electromagnetic radiation

• high energy/ short wave length

deep penetration

principles of a radiograph

image is produced by x-ray penetrating through the body onto a film cassette

various structure absorb energy differently

what is radiodensity? explain more and less radio dense

thickness anatomical weight (composition) of the structure

more radiodense

• radiopaque (white)

  • contrast- medium

    • barium

  • metal implant

    • metal rod or nail

less radio dense

• radiolucent ( dark)

  • air

What are the radiographic projections? how many are needed? any exceptions? (5)

at least 2 projections; 90 degree separation

• superimposition/ alignment

more than 2 projections needed

• radial head

• femur

• scapula

• humeral head

• shoulder impingement

What things matter when it comes to radiographic projections?

direction of the x- ray/ film cassette

• antero-posterior vs portero-anterior

position of the patient

( in relation to the x-ray beam )

• sagittal, frontal, transverse

• sagittal, coronal, axial

what are the 2 different type of projections

lateral projection (frontal plane)

• named for the side closest to the film cassette

  • ex: right lateral projection= right close to film

oblique projection

• approximately 45 degrees from the sagittal plane

• named for side closest to film cassette

what is digital radiology?

stores the diagnostic image in the computer

computer reproduces the image

mostly what is used now!

when using a systemized approach to imaging: what are the ABCs?

A- alignment

• general skeletal architecture

• general contour of bone

• alignment of bone relative to adjacent bones

B- bone density

• general bone density

• texture abnormalities

• local bone density

C-cartilage spaces

• joint space width

• subchondral bone

• epiphyseal plates

s- soft tissues

• muscles

• fat pads and fat lines

• joint capsules

when analyzing a radiograph, what do you correlate? (3)

history

physical examination

diagnostic image findings

what is the primary indication for conventional radiology?

bone injury

what are the principles of a computerized tomography?

radiographs taken in 360 degree fashion

patient is place on a table moving through a circular ring

radiographs are taken axially ever .3 to 1.5 cm

pros to CT scans

complex fractures/ tumors

eliminates superimposition of one anatomical part on another

can look at blood flow

cons to CT scans

insufficient for visualization of articular cartilage, tendon rupture/ tendonitis

What are the principles for fluoroscopy?

x ray beams passes through the patient and

Interacts with an image intensifier tube

Image is transferred to a screen

Image can be static or dynamic

when is fluoroscopy used?

during casting, splinting, surgery

when is fluoroscopy indicated?

In the O.R for fracture reduction/fixation

For observing abnormal movements of a joint (stress on a joint structure)

what are the negative factors of fluoroscopy?

increased radiation

poor quality image

Indications for x-ray absorptiometry?

bone density may be evaluated radiologically

changes in bone density are termed osteopenia

• osteoporosis is a pathology

plain- films are not very sensitive to changes in bone density

what are the principles of x-ray absorptiometry?

bone densitometry is the general name for all radiological studies for osteopenia

bone densitometry uses standard anatomical parts as a reference and compares these to a normative model

lumbar spine, prox. femur, distal radius, calcaneus are commonly used

What does the dual x-ray absorptiometry (DEXA) measure?

measures the changes of an x-ray beam from two level of energy as it passes through the body

What do the Quantative CT (QCT) look at and what does it assess?

takes a CT of 3 lumbar vertebrae ( normally L1-L3)

assess bone density against a normative model

What are the principles of a bone scan?

Nuclear medicine study that is very sensitive to changes in bony metabolism

good sensitivity, poor specificity

may need to follow up with the other studies (MRI, CT) to complete the diagnosis

What is bone scan procedure?

radiopharmaceutical agent is inject

pt is placed under a scintillation camera

entire body scanned simultaneously

side to side comparison is possible

normal bone is lighter than pathologic bone (dark) bone

Indications for a bone scan?

Tumors

Metastatic disease

Infections

stress reactions

fractures

avascular necrosis (AVN)

What are the principles of magnetic resonance imaging (MRI) ?

Produced by the interaction of tissues with radio frequency within a magnetic field

Each tissue type has typical energy pattern

Computer reconstructs the image

what are the indication for magnetic resonance imaging?

ideal for imaging bone, soft tissue leasions, surgicial planning

stress fractures

AVN/tumors

ligament injury

bone marrow edema

articular cartilage/ meniscus cartilage

head trauma/spinal cord injured

How do T1 MRIs appear?

Bone, fat, and subacute hemorrhage are bright

fluid, and soft tissue are dark

how do T2 MRIs appear?

fluid and soft tissues are bright

• poor resolution

T1 and T2 weighted images are used for what?

T1 weight images anatomy detail

T2 weight images used for acute trauma

principles for contrast enhanced imaging? (contrast medium)

Injected (radiopaque/ radiolucent) into an anatomical part followed by a radiograph

improved visualization of pathology

can be used with most diagnostic imaging modalities

what is anthrography?

injection of a medium into a joint

OCD, rotator cuff tears, TFCC

What is myelography?

injection of a medium into the spine

spinal cord, nerve roots, dure mater

Diagnostic ultrasound principles

Most commonly used to image soft tissue lesions in tendon and muscle

Does not use ionizing radiation

Image quality is not as good as CT or MRI

Coming more popular

diagnostic ultrasound indications

prevalent in research and some PT practices

pre and post movement re-education

• abdominal muscles

• pelvic floor

  • urinary incontinence

• lumbopelvic