MSK Radiology

Question 1

What’s the initial modality for MSK complains?

Answer 1

X-ray (radiography)

Question 2

X-ray

Answer 2

Images obtained by projecting X-ray beams through a subject onto an image detector
Available on film/digital

Question 3

Indications of radiography

Answer 3

Fractures, dislocations, bone fixation, arthritis, bone tumors, skeletal dysplasia

Question 4

Contraindications of X-ray

Answer 4

Exclusively soft tissue injuries, early presentation of certain soft tissue conditions, primarily medullary bone diseases, caution with excessive repeat images and unnecessary radiation

Question 5

Advantages of radiography

Answer 5

Readily available, reproducible, inexpensive, patient ease cause happens in seconds, don’t need technical training to to interpret, can do real-time radiography (fluoroscopy can help)

Question 6

Limitations of radiography

Answer 6

Images are larger than subject and must be calibrated, superimposed structures (3D data creating a 2D image), exposure, low sensitivity for subtle fractures and soft tissue injuries

Question 7

Principle views of radiography

Answer 7

Posterior/Anterior or Anterior/Posterior, lateral, obliques, may need to supplement views specific to site

Question 8

Computed tomography (CT)

Answer 8

Sophisticated X-rays, uses X-rays and produce tomographic images (imaging in sections and then formatted into cross sectional cuts)
Contrast mediums- iodinate materials, barium and air

Question 9

Indications of CT

Answer 9

Combine with contrast medium to image joints, stereotactic frame (biopsies, surgical planning, radiation therapy), angiography, staging of complex fractures, small intraarticular fragments/loose bodies, fracture healing, bone tumors

Question 10

Contraindications of CT

Answer 10

Unnecessary imaging, significant metal in the area, allergy or inability to tolerate contrast dye (renal insufficiency), pregnancy should be avoided unless severe

Question 11

Advantages of CT

Answer 11

Tomography, best bone Assessment modality, higher contrast resolution images (avoid overlapping structures), digital nature allows for reconstruction, interventional options, well tolerated and generally quick

Question 12

Limitations of CT

Answer 12

Artifacts so blurring from patient movement, beam hardening from hardware, limited use for soft tissue, requires large physical site, limitation on size (300-400 lbs), higher cost than X-ray, radiation exposure, claustrophobia

Question 13

Views of CT

Answer 13

Sagittal (divide right and left), coronal (divide Anterior and Posterior), axial (horizontal so divides superior and inferior)
MRI has similar planes

Question 14

MRI

Answer 14

Images produced by reconstruction of data set, utilizes strong magnetic field with radio frequency pulses and collects differences in tissue signal intensity, performed with patient usually supine and by the specific body site

Question 15

Advantages of MRI

Answer 15

Superior contrast resolution, ideal for soft tissue pathology while still good for bone, highly sensitive, contrast compounds generally safer than CT contrast medium (because gadolinium based)

Question 16

Limitations of MRI

Answer 16

More severe artifact than CT (motion and metal), large shielded imaging suite, magnetic field, claustrophobia, expensive, one exam for one body part and average time is 45 min

Question 17

Indications of MRI

Answer 17

Intrarticular soft tissue structures, MR arthrograhy, superior sensitivity in diagnosis of early detection of bone marrow conditions, stress fractures and malignancy, more of a problem solving tool

Question 18

Contraindications of MRI

Answer 18

Pacemakers, mechanical pumps, electric stimulators, foreign bodies in eye, any other metal products

Question 19

What’s the difference between T1 and T2 MRI?

Answer 19

T1 is better for anatomic Assessment because fat is bright and fluid is dark (1 Big Mac to be fat)
T2 is better for fluid Assessment so fat and fluid are both right and highlight soft tissue injuries

Question 20

Ultrasound

Answer 20

Sound waves produce images, transducer transmit sounds and detects reflected sound waves, tomographic, echogenicity frequency of sound waves (low is cystic, high is solid mass), doppler measures motion

Question 21

Advantages of ultrasound

Answer 21

Beneficial for soft tissue (tendons and muscles), low cost, well tolerated, no known harmful effects, highly protable, unossified epiphyses

Question 22

Limitations of ultrasound

Answer 22

Artifacts, not available everywhere, limited by skills of provider, minimal use in evaluating bone

Question 23

Indications for ultrasound

Answer 23

Often study of choice in infant for multiple conditions, soft tissue conditions in adults, guided assistance for joint infections, biopsies, soft tissue drainage

Question 24

Contraindications of ultrasound

Answer 24

NONE in orthopedics

Question 25

Nuclear scintigraphy

Answer 25

Nuclear medicine imaging, most common is bone scan (IV injection of radioisotope bound to phosphate as a tracer, imaging can then be seen between 1 min and 24 hours after) Tracer will distribute in metabolically active bone at 2-4 hours Can be single view of cross-sectional

Question 26

Indications for bone scan

Answer 26

Osteomyelitis, metastases, bone tumors, occult fractures

Question 27

Contraindications of bone scan

Answer 27

Avoid in children and pregnant women when possible

Question 28

Advantages of bone scan

Answer 28

Very sensitive for skeletal pathology (because if its negative for something there is nothing there), mildly sensitive for soft tissue concerns

Question 29

Limitations of bone scan

Answer 29

Non-specific, lack detail, lower sensitivity in early fractures with slow healing potential, used in combo with other imaging, radiation exposure

Question 30

Types of complete fractures

Answer 30

Transverse, oblique, spiral, avulsion, comminuted (multiple pieces)

Question 31

Types of incomplete fractures

Answer 31

Torus (buckle), greenstick, bowing

Question 32

Why do kids get incomplete fractures?

Answer 32

Periosteum

Question 33

What is the periosteum?

Answer 33

Part of the bone that is more metabolically more active and promotes callus formation and remodeling activity Thicker and more durable, less likelihood of displacement and gives the unique fracture presentations

Question 34

Where do you see compression fractures the most?

Answer 34

Spine

Question 35

Salter-Harris classification of fractures (in skeletally immature patients)

Answer 35

I-separate (runs along physis/growth plate) II- above (through metaphysis- which is proximal to growth plate) III-lower (goes out epiphysis which is distal to growth plate) IV- through (through 2 levels) V-reduced (crushing and erasing of growth plate)

Question 36

Concerning features of bone tumors and lesions

Answer 36

Indistinct margins, abnormal periosteal reaction, soft tissue mass/invasion, rapid growth, pathologic fracture

Question 37

Terms of displacement

Answer 37

``` Nondisplaced and displaced Translation (often referred to as displacement)- use percents Angulation Rotation Shortening Bayonetted (overlap) Distracted/impacted ```

Question 38

Occult fracture

Answer 38

Fracture of a bone that is difficult to see on an xray so it tends to be missed (scaphoid is common)

Question 39

Contributing factors to fracture malunion or nonunion

Answer 39

Use of oral steroids, poor bone contact, loss of bone, interruption of blood supply, excessive motion, age, poor nutrition, tobacco use