Musculoskeletal Imaging Flashcards by Jing Ji

What is conventional radiography used for in musculoskeletal imaging?

gas

foreign bodies

tissue calcification/ossification

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In an x-ray how many views must be taken at a minimum?

2 views perpendicular to one another

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What are the advantages of conventional radiography for musculoskeletal imaging?

widely available

reproducible - standard protocols are available

inexpensive

minimal ionizing

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What are the limitations of using conventional radiography for musculoskeletal imaging?

fractures may be occult if not displaced

importance of more than 1 view

complex bones and superimposed structures may limit evaluation

soft tissues are poorly evaluated with x-ray

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What is CT used for in musculoskeletal imaging?

excelent evaluation of bone detail and calcifications

used for more detailed evaluation of fractures

preoperative planning

assessment of healing

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What are the advantages of CT in musculoskeletal imaging?

widely available - short imaging time

excellent spatial resolution - occult fracture detection

can be done with or without contrast

can reformat images

alternative if MRI is contraindicated

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What are the limitations of CT in musculoskeletal imaging?

ionizing radiation

high cost

soft tissue evaluation is inferior to MRI

metal causes artifact

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What are the advantages of using MIR for musculoskeletal imaging?

high contrast resolution for soft tissue and bone

shows pathophysiologic events earlier than seen on x-ray

no radiation

widely available

large variety of imaging techniques

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What are the limitations of using MRI for musculoskeletal imaging?

expensive

not patient friendly - claustrophobia and time intensive

quality varies between institutions and individual magnets

metal causes artifact

several absolute contraindications

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What are the absolute contraindications of MRIs?

pacemakers - cardiac and GI

electronic stimulators

metallic foreign objects in or around the orbit

weight limit

contrast allergy

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What are the relative contraindications for MRIs?

aneurysm clips

retained bullet fragments and metallic objects

renal function

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What is fluoroscopy used for in musculoskeletal imaging?

most commonly used by radiologists for procedures

can be used to evaluate joint motion/dynamic imaging

used frequently by orthopedic surgeons during hardware placement

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What are the advantages of fluoroscopy in musculoskeletal imaging?

widely available

dynamic imaging

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What are the limitations of fluoroscopy in musculoskeletal imaging?

ionizing radiation to the patient and the operator

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What is the use of ultrasound in musculoskeletal imaging?

excelent for superficial soft tissue structures such as tendons and muscles

limited evaluation for the surface of bones but not the test of choice

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What are the advantages of ultrasound in musculoskeletal imaging?

patient friendly - no radiation or contrast

reproducible

small to moderate expense

widely available equipment

dynamic imaging

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What are the limiations of ultrasound in musculoskeletal imaging?

extremely user/operator dependent

cannot be transmitted through cortical bone

not the test of choice for medullary space

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What are the two most common bone imaging studies used in nuclear medicine?

bone density studies and technetium bone scans

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What is the most important determining factor of bone fragility?

bone mineral density (BMD)

expressed as grams of mineral per area or volume

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What is bone density measurement used for?

used to identify individuals at risk for developing osteoporosis or fracture

compared to age-matched, ex-matched, and race-matched controls

Who gets bone density measurements?

all menopausal women 65 years or older

menopausal women with under 65 with risk factors

premenopausal women 65 years or older

premenopausal women with 1 or more low-trauma fractures, women being treated for osteoporosis and people receiving long-term glucocorticoid therapy

What is dual x-ray absorptiometry (DXA_

uses pulse photons at alternating energies

about 1/1000 radiation of a routine spine film

time of exam is short (2-5 minutes)

standard exam includes imaging of the lumbar spine and proximal femur

How are bone density measurements using DXA scored?

scoring of bone density using T-score and Z-score

Where is osteoporosis most pronounced

trabecular bone

What are osteoporotic fractures most commonly associated with?

areas of high trabecular content (vertebral body, femoral neck, distal radius)

What is the T-score in bone density measurements? How is it interpreted?

T-score is the difference between BMD of the patient and the mean MBD of a standard young adult population matched for sex and ethnicity more useful than the z-score osteopenia is defined as BMD between 1 and 2.4 standard deviations below reference mean \<2.5 is osteoporosis severe osteoporosis is \<2.5 and one or more low-trauma fractures

What is the Z-score in bone density measurements?

the difference between the patient BMD and the mean BMD of age and gender matched controls

What are the limitations of dual x-ray absorptiometry (DXA)?

severe degenerative disease of the spine aortic calcifications compression fracture of the spine

What is bone scintigraphy?

a photon emitting substance is tagged to a compound and injected intravenously most common agent used is technetium labeled methylene diphosphonate sensitive but not specific

What conditions are bone scintigraphy sensitive for?

conditions which result in bone turnover and increased blood flow, specifically fracture, infection, and blastic metastases (prostate, breast) they provide physiologic rather than anatomic information

What contributes to increased uptake of the agent in bone scintigraphy?

increased blood flow areas and rate of new bone formation interruption of sympathetic supply

What are the limitations of bone scintigraphy?

ionizing radiation time sensitivity - radioisotope is injected and imaging is performed after several hours (3-6 hours)

What are the invasive image guided procedures?

image-guided biopsy arthography myelography

What is arthrography?

technique used to introduce contrast into a joint the contrast contains iodinated compound allowing visibility on radiographs, CT, and fluoroscopy gadolinium injected for MRI imaging

What is arthrography best for?

evaluation of the joiints: - labrum (shoulder and hip) - cartilage - rotator cuff tendons - intrinsic ligaments of the wrist and elbow

What are the contraindications of arthrography?

contrast allergy same as for MRI

What is myelography?

technique used to introduce contrast into the central canal contrast contains iodinated compound allowing visibility on fluoroscopy and CT

What are the advantages of myelography?

can be used if MRI is contraindicated better evaluation of bone and its effects on the neural foramen and central canal dynamic imaging allows for evaluation of the canal with flexion and extension

What are the limitations of myelography?

ionizing radiation contrast allergy inferior sofy tissue evaluation compared to MRI invasive

What are the uses of image guided biopsy?

multiple modality choices safer alternative to surfical/open biopsy - outpatient procedure used for lesions of unknown etiology confirms diagnoses staging of disease

What are the types of image-guided therapy?

corticosteroid injections calcific tendinnitis lavage vertebroplasy thermal ablation

What is the plan of action for imaging of chronic back pain?

plain radiographs and then MRI in an adult plain radiographs and then nuclear medicine exam or MRI in children

What is the imaging procedure for acute back pain?

plain radiograph consider CT if related to direct trauma MRI

What is the imaging procedure for neck pain?

plain radiograph series if normal bit still significant pain/symptoms consider MRI CT useful in acute setting/trauma patient

What is the imaging procedure in joint pain?

plain radiographs consider MRI if looking for soft tissue injury of ligament, cartilage, tendon, or muscle

What is the imaging procedure for neoplasms?

plain radiograph MRI with contrast - if osseous, just image "joint to joint" and evaluate for skip lesions CT nuclear medicine study - osseous metastasis

What is the imaging procedure for occult fractures?

plain radiographs if x-ray normal - CT, MRI, or nuclear medicine study

What is the imaging procedure for osteomyelitis?

in a diabetic patient, use plain radiograph, MRI, or nuclear medicine study in non-diabetic patients, use plain radiograph or MRI with contrast