01-02 - General Principles of Diagnostic Imaging

Purpose of studying musculoskeletal imaging

• Physical Therapists should expand their capabilities to know what could be the best tx or best dx that therapists could give to their patients

• More comprehensive evaluation is obtained

Musculoskeletal imaging

A subspecialty of radiology concerned with the diagnostic evaluation of the musculoskeletal system

Musculoskeletal radiology / orthopedic radiology

Previous term for MSK imaging

2 uses of radiation

Diagnosis and treatment

Radiograph

Has been defined for over a century as an x-ray film containing an image of part of a patient’s anatomy

Image receptor

Other term for X-Ray

• X-ray beam source

• Patient

• X-ray film / other image receptor

Production of a radiograph requires these 3 things:

X-rays are named after the letter “X” in the alphabet because they were discovered by accident, and at the time of their discovery, the nature of these rays was unknown.

• The term “X” was used to signify the unknown or mysterious nature of these rays

Why is x-ray called x-ray?

Wilhelm Conrad Roentgen (Nov 8, 1895)

The German Physicist who discovered X-ray

Marie Curie and Pierre Curie

Discovered the radioactive elements polonium and radium; the beam of light/x-ray creates radiation

Bone portraits

First image caught by Roentgen (Hand of his wife)

Radiation

energy that is transmitted through space or matter

Ionization

process by which a neutral atom gains or loses an electron, thus acquiring a net charge

Falls ate ko 😘 (Lesser Ionization, gains electrons; higher ionization, lose electrons)

T or F: Lesser Ionization, lose electrons; higher ionization, gains electrons

• Radio waves

• Microwaves

• Infrared radiation (IRR)

• Visible light

• UV radiation

Examples of Non-Ionizing Radiation

• X-rays

• Gamma rays

• Certain particles (alpha and beta)

Examples of Ionizing Radiation

Plain X-ray

Most frequently performed radiological test worldwide

Chrew yan ate

T or F: The more an object absorbs the radiation, the more it appears white = if the object/tissue is solid (ionization).

• Chest and Lung Dse

• Heart Dse

• Bone and Jt Dse

• Trauma (Fracture)

• Tumors

• Requirements

• Foreign body

Uses of Plain X-ray

• Posteroanterior View

• Anteroposterior View

• Lateral View

• Oblique View

Different views of Plain X-ray

Central Ray

The PA View and AP View have positioning that they use which is called _____.

PA View

Most commonly used chest x-ray to reduce the overlap of the anatomic structures

AP View

Mostly used for abdominal x-rays

T7 level

Central ray level

Jugular notch

Recommended landmark for the location of the CR for AP chest radiographs.

FALLS PO YAN ATE perpendicular yarne

T or F: The central ray (CR) is set parallel to the long axis of the sternum and the center of the cassette

Standard appearance of a test in x-ray

Lateral view

View used to examine spine, ribs, and extremities

Oblique view

View used better used to visualize fractures that are maybe obscured by a standard view.

• Scottie dog

• Fracture

• Spondylolysis

• Spondylosis

• Possible arthritis

• Possible calcification

Uses of oblique view

Dual Energy X-Ray Absorptiometry (DEXA)

Measures bone mineral density = amount of calcium + other minerals (mg/cm^2 of calcium)

Hips, Lumbar spine, Calcaneus, Forearm

Sites usually tested for DEXA

• Postmenopausal women = > 65 y/o

• Women < 65 with high risk for fractures

• Men 70 y/o or older

• Men 50-69 y/o with risk factors

Indications of DEXA

• Smoker

• 3 or more alcohol intake/day

• Chronic kidney dse

• Family hX of osteoporosis

• Early menopause < 45 y/o

• Hx of fragility fractures

• RA/ Systemic Arthritis

• Chronic corticosteroids

• Organ transplant

• BMI < 21

• Sedentary / lack of exercise

• Low testosterone (prostate CA)

• Loss of height (4 cm)

Identify atleast 3-5 High Risk Factors for Fx

• Identify decreases in bone density before one gets a fracture

• Determine risk of fragility fractures

• Confirm a diagnosis of osteoporosis

• Monitor osteoporosis treatment

Benefits of DEXA

• Between 1 and -1 = normal

• Between -1 and -2.4 = osteopenia

• Between -2.5 and below = osteoporosis

T-Score

• Between 1 and -1 = ______

• Between -1 and -2.4 = ______

• Between -2.5 and below = ______

Computed Axial Tomography Scan / CAT / CT Scan

More sensitive in detecting presence of blood; also uses ionizing radiation; size, shape, & position of internal organ / structure

• Radiation

• More costly

• Pregnancy precaution

Disadvantages of CT Scan

MEDICAL ULTRASOUND / SONOGRAPHY

Evaluates ligaments, tendons, muscles, nerves, joints; view anatomical part as it moves in real time; no radiation, safe, non-invasive, portable, pregnant

15-30 mins

Duration of Medical Ultrasound

Hyperechoic (white); Hypoechoic (black/dark)

What do you call the white and black/dark portion of this ultrasound?

• Tendinitis vs tear

• Muscle tear, mass, fluid collection

• Ligament sprain vs Tear

• Joint effusion, Bursitis

• Early changes of RA

• Nerve entrapment

• Soft tissue tumors

• Ganglion cyst

• Hernias

• Foreign body (splinters)

Give atleast 3 indication of MSK Ultrasound

• Non-invasive, Safe, Painless, No radiation

• Widely available, Cheaper

• Gives a clear picture of soft tissues not visible on

• Real time images - Interventions (aspiration, injection, biopsy)

• Pt. with metal implants

• Alternative to claustrophobic patients

• Shows mvts of soft tissue structures

• 15-30 mins

Benefits of MSK Ultrasound

• Depth of penetration (NOTE: only capable of shallow penetration)

• Cannot penetrate bones

• Obese & large individuals

LIMITATIONS OF MUSCULOSKELETAL ULTRASOUND

Echocardiogram / Echo / 2D Echo

anatomical images of heart only

Doppler echocardiogram

can see how fast the pump blood

• Identify cardiac causes of dyspnea

• Cardiomegaly, ventricular or atrial hypertrophy

• Cardiomyopathy — weakened heart muscles

• Valvular heart disease

• Congenital heart disease

• Blood clot or tumors

• Pumping strength of the heart

• To monitor effectiveness of treatment

INDICATIONS FOR ECHOCARDIOGRAM

TRANSESOPHAGEAL ECHOCARDIOGRAM

Catheter containing the transducer is inserted into esophagus; more accurate picture of heart

TRANSTHORACIC ECHOCARDIOGRAM

Pt. supine c transducer on chest ; sometimes pt. might feel a really deep pressure/ some discomfort; chambers of heart, mitral and tricuspid valves, etc

STRESS ECHOCARDIOGRAM

Done while pt. is exercising to the point of exhaustion (done on treadmill or stationary bike c electrodes attached)

• Monitor for ischemic changes, CAD

• No food, drinks for 4 hours

• No caffeine, chocolates, tea for 24 hours

• No cardiac medications (e.g. beta-blockers & nitroglycerin)

Stress Echocardiogram Conditions to Follow

DOBUTAMINE STRESS ECHOCARDIOGRAM

Done when pt. cannot exercise; clinician will give medicine that will cause an effect like the person is exercising

• Cardiomyopathy

• Congenital heart disease

• Heart failures

• Aneurysm

• Valvular heart dse (stenosis or regurgitation)

• Cardiac tumors

• Tumors outside heart, inside chamber, in myocardium

• Pericarditis

• Pericardial effusion/tamponade

• Fluid in the pericardial sac

• Septal defects

• Shunts

INTRAVASCULAR ULTRASOUND USES

DOPPLER ECHOCARDIOGRAM

Determines speed & direction of blood flow (echocardiogram)

• Cardiac function

• Valves

• Septal defect

• Regurgitation

• Cardiac output

VELOCITY MEASUREMENT (DOPPLER ECHOCARDIOGRAM)

• safe

• portable

• can get a lot of info

ADVANTAGES OF DOPPLER ECHOCARDIOGRAM

• Thickness of heart

• Functions of valves

• Appearance of blood vessels

• Flow of blood

• Size & shape of heart

• How is it in its function in pumping blood to the circulation

THINGS THAT CAN BE EVALUATED USING DOPPLER ECHOCARDIOGRAM

20-40 mins

Duration of Doppler Echocardiogram