SM 226a - MSK Imaging Flashcards by Amelia Hansen

Which imaging modality is most commonly used during musculoskeletal procedures?

Which kinds of procedures?

Fluoroscopy

Used when injecting contrast (for arthrography), or steroids

Used to guide synovial fluid sampling

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What are the imaging recommendations for evaluating neck pain?

Plain x-ray series
Consider MRI if x-rays are normal but there signfiicant pain or other symptoms

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What is the role of ultrasound in the evaluation of musculoskeletal pathologies?

Evaluation of superficial soft tissues

Tendons, ligaments, nerves

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Relative or absolute contraindication to MRI?

Aneurysm clips

Relative

(Consider postponement or other imaging modalities if posisble)

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Describe the scoring system for Dual X-ray absorptiometry

T-score: Difference between bone mineral density of patient and the standard young adult population
- <1 SD from the mean = normal
- 1-2.4 SD from the mean = osteopenia
- >2.5 SD from mean = osteoporosis
- >2.5 SD from mean + one or mor low-trauma fractures = severe osteoporosis
Z-score: Difference between bone mineral density of patient and the standard for patients that age (same ranges)

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Relative or absolute contraindication to MRI?

Stimulator

Absolute

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Which imaging modality usually guides soft-tissue procedures?

Ultrasound

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What information can we learn from PET imaging?

Identify areas of increased metabolic activity

Useful in finding and evaluating cancer metastasis

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What are the uses of image-guided biopsy?

Evaluate a known lesion of unknon etiology

Confirm a diagnosis

Staging of disease

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Relative or absolute contraindication to MRI?

Patient’s weight exceeds the weight limit

Absolute

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What are the advantages of bone scintigraphy?

What are the disadvantages?

Advantages
- Sensitive
- Provides physiologic information about bone homeostasis
- Localize areas of high bone turnover/deposition
  - Identify sites fo tumor or metastasis
- Can do whole-body imaging
Disadvantages
- Not specific
- Time-intensive (4-6 hours)
- Exposure to ionizing radiation

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What imaging modality will uncover areas of rapid bone turnover?

Bone scintigraphy

(A type of nuclear medicine)

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What is a myelogram used for?

What can we learn?

Contrast is introduced into the thecal (dural) sac; contrast injection is guided by CT or fluorscopy

CT evaluates where the contrast has gone

This helps us see if there is a bone or soft tissue pathology that is affecting where the contrast goes after it is injected

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What are the contraindications to arthrography?

Contrast allergy

Same as contraindications to MRI

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What are the advantages of fluoroscopy?

What are the disadvantages?

Advantages
- Dynamic imaging
Limitations
- Radiation exposure to patient and operator

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What is bone scintigraphy?

What is it used for?

A whole-body bone scan

Normal result = normal bone
Abnormal result indicates an area of the body with high bone turnover, but does not reveal the specific pathology
- Provides physiologic information

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Relative or absolute contraindication to MRI?

Pacemaker

Absolute

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What are the imaging recommendations for evaluating a neoplasm

Plain x-ray
MRI with contrast
- If osseous, must image joint to joint
  - Ex: if concerned about femur, get knee through hip
- Contrast helps us see if there is active blood flow (necrosis or hemorrhage)
CT
Nuclear medicine study
- Bone scintigraphy or PET CT to identify osseous metastasis

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What are the imaging recommendations for evaluating osteomyelitis in a non-diabetic patient?

Plain radiograph
MRI with contrast

What are the relative contraindications for MRI?

Aneurysm clips

Metal

Which imaging modality usually guides bone biopsy?

What are the imaging recommendations for evaluating osteomyelitis in a diabetic patient?

Plain x-ray
MRI
- No contrast due to impaired renal function
Nuclear medicine study

What conditions could result in a positive bone scan (bone scintigraphy)?

Anything that leads to increased bone deposition and blood flow

Fracture healing
Infection
Biastic metastases
Tumor

What are the advantages of ultrasound in the evaluation of musculoskeletal pathologies?

What are the disadvantages?

Advantages
- Patient friendly
  - No radiation or contrast
- Dynamic imaging
  - Some pathologies are only evident when the patient is moving
- Inexpensive
Limitations
- User-dependent
- Not great for looking at bone

What is the role of nuclear medicine in the evaluation of musculoskeletal pathologies?

Detect osteoporosis and fracture risk Example: Dual x-ray absorptiometry (DXA)

What are the advantages of MRI in the evaluation of musculoskeletal pathologies? What are the limitiations?

* Advantages * Superior evaluation of joints, soft tissue, and cartilage * Superior contrast resolution * No rdiation exposure * Limitations * Not patient-friendly * Takes a long time * May induce claustrophobia * Obese patients

What are the imaging recommendations for evaluating joint pain?

* **Plain x-ray** * Consider MRI if you are looking for a soft tissue injury * Ultrasound may be used to evaluate superficial tendons

What are the advantages of conventional radiography? What are the limitations?

* **Advantages** * **Inexpensive** * **Reproducible**; can follow a disease process over time within an institution or between different institiutions * **Minimal radiation** * **Limitations** * **Occult fractures**; may be hidden if structures overlap * **Limited evaluation of soft tissue** * **Must have at least 2 views**

Which imaging modality will help us determine a patinet's risk fo osteoporosis and fracture?

Dual x-ray absorptiometry | (A type of nuclear medicine)

What procedures require image guidance?

* Biopsy * Arthrography * Myelogram * Therapy * Corticosteroid injection * Calcific tendinitis lavage * Vertebroplasty * Thermal ablation

Relative or absolute contraindication to MRI? ## Footnote **Metal in the orbit**

Absolute

What are the advantages of a myelogram? What are the limitations?

* Advantages * Can be used if MRI is contraindicated * Evaluation of the bone * Dynamic imaging is possible * Disadvantages * Contraindicated for patients with contrast allergies * Exposure to ionizing radiation * Invasive procedure; potential injury to nerve roots * Not as good as MRI for soft tissue evaluation

What are the imaging recommendations for evaluating chronic back pain in an adult?

* Plain x-ray * MRI for follow-up or if indicated by x-ray findings

List three types of nuclear medicine commonly used in musculoskeletal medicne. What is each one used for?

* Dual x-ray absorptiometry * Evaluates bone density to evaluate risk of ostoporosis and fracture * Bone scintigraphy * A "bone scan" * Uncovers areas of rapid bone turnover * Sensitive but not specific * PET scan * Identify areas of increased metabolism * Useful in identifying and evaluating metastases

What is dual x-ray absorptiometry (DXA)?

A type of nuclear medicine that helps to detect osteoporosis and evaluate fracture risk * Low resolution x-ray images of the lumbar spine and proximal femer * This helps determine if the patien thas a loss in bone mineral density that would increase their risk of osteoporosis and fracture

What are the indications for x-ray?

Evaluation of... * Trauma * Infection * Arthritis * Mechanism of injury * Need for MRI

What are the imaging recommendations for evaluating occult fractures?

* Plain x-ray (at least 2 views) If x-ray is normal but there is concern for injury, consider CT, MRI, nuclear medicine study

Describe the advantages and disadvantages of CT imaging

* **Advantages** * ****Superior spatial resolution * Multi-planar images possible * Widely available * Fast * **Disadvantages** * More expensive than x-ray * More ionizing radiation * Artifact with metal - may degrade the quality of the image

What are the imaging recommendations for evaluating acute back pain?

* **Plain x-ray** * Consider CT if related to direct trauma * MRI if there is suspicion of soft-tissue injury

What is arthrography? What is it used for?

Arthrography introduces contrast into the joint so that we can evaluate the joints Usually in conjunction with MRI; "MRI with contrast" Used to evaluate: * Labrum (potential tears) * Cartilage * Rotator cuff tendons * Intrinsic ligaments

List the absolute contraindications to MRI

* Cardiac devices; pacemakers or stimulaors * Metal in the orbit * Patient's weight exceeds weight limit

If MRI is contraindicated, which alternative imaging can be used?

Myelogram (Introduce contrast to the dural sac, use CT to see where it goes)

What are the imaging recommendations for evaluating chronic back pain in a child?

* **Plain x-ray** * will catch most pathologies in adolescents * Nuclear medicine exam * MRI only if previous tests are inconclusive and there is suspicion that something is wrong

Relative or absolute contraindication to MRI? ## Footnote **Recently-placed metal in the body**

Relative - may migrate or heat up Postpone imaging or use other modality if possible

What imaging modality is the mainstay for evaluation of bones?

Conventional radiography (x-ray)