Musculoskeletal Imaging Modalities Flashcards
1
Q
Describe the historical development of medical imaging tools & techniques
A
- Roentgen created the X-Ray in 1895
- named an X-Ray due to unknown type of radiation
2
Q
Describe radiology
A
- branch of medicine dealing with radiant energy, radioactive substances (X-Ray), radioactive isotopes or ionizing radiation
- used for prevention, diagnosis, & treatment of disease
2
Q
Describe radiation
A
- mechanical, electrical, thermal, nuclear, & electromagnetic energy all emit radiation
- Ionize atoms = ionization (results in disruption of the composition of matter & disrupts life process)
3
Q
Radiology modalities
A
- Musculoskeletal: X-Ray (ionizing), CT (ionizing), MRI (non-ionizing), Bone scan (ionizing), Ultrasound (non-ionizing)
- Neurological/Advanced imaging: diffusion weighted imaging/DWI (non-ionizing), cortical morphometry (non-ionizing), susceptibility weighted imaging/SWI (non-ionizing), myelin water imaging.MWI (non-ionizing)
- MRI & CT are done for both musculoskeletal and neurological
4
Q
Describe X-Rays/Radiographs
A
- 1st order diagnostic study
- excellent at viewing basic boney anatomy
- Drawbacks: ionizing radiation, harmful to biological tissue, lacks ability to demonstrate soft tissue structures, & unable to appreciate complex boney anatomy structures
- cheap, easy to take, not cumbersome for the patient
5
Q
How do X-Rays work
A
- Electricity applied to cathode
- Electrons emitted and strike anode target
- Target reflects electrons to emit an X Ray beam
- Beam passes through anatomy
- Image receptor takes latent image and produces visual image
6
Q
Production of images (X-Rays)
A
- Flesh = lower atomic weight (transparent)
- Bones = higher atomic weight (attenuate)
- absorption of radiation depends on substance’s density & atomic weight
- Attenuation: the degree to which x-rays are absorbed/deflected by the body part
7
Q
Describe radiodensity
A
- The physical qualities of an item/object that determines how much radiation it can absorb from a x-ray beam
- Composition (# of electrons in the object)
- Density (thickness)
- Radiolucent = easily penetrated by X ray beams
- Radiopaque = not easily penetrated by X ray beams
8
Q
Order of most radiolucent to most radiopaque for X-Rays
A
- Air = black (radiolucent)
- Fat = dark gray
- Water = medium gray
- Bone = off white/light gray
- Metal = white (radiopaque)
9
Q
Describe contrast enhanced imaging
A
- Angiography: injection of contrast into the blood supply of an organ
- Arteriography: injection into a specific artery to determine blood flow
- Arthrography: joint
- Myelography: injection of material around the subarachnoid space to show abnormalities of the spinal cord
- Contrast medium is injected or ingested into the body to improve visualization by increasing radiographic contrast in areas with minimal inherent contrast (static or dynamic images)
10
Q
Describe fluoroscopy
A
- X-Ray exam in real time
- commonly used in fracture fixation, orthography, pyelography, discography, biopsy, gastrointestinal evaluation
11
Q
Describe conventional tomogram
A
- X-Ray technique
- allows for precise localization of lesions as small as 1mm
- used for fractures around irregularly shaped bones & healing of fractures
- high radiation, image easily impacted by motion
- replaced by CT & MTI
12
Q
Describe CT (computed tomography) scan
A
- X-Ray technology with advanced computer processing (all digital)
- creates images based on cross-sectional slices
- excellent demo of cortical bone anatomy, but poorer soft tissue demo
- fast, esy to perform, readily available
- multi planar & 3-D images
- costly & high radiation dosage
13
Q
Indications for a CT scan
A
- trauma
- subarachnoid hemorrhage
- acute cervical spine injury
- acute appendicitis
- ureteric calculus
14
Q
Contraindications for a CT scan
A
- pregnancy
- young age
- claustrophobia
- allergy to contrast medium
- weight/girth
15
Q
What does a CT scan do best
A
- evaluate for loose bodies in joint
- Not as claustrophobic for patients
- Cheaper than MRI, but still expensive
- Very accurate
- Usually 1st imaging choice in trauma patients
- Best for subtle fractures, complex fractures, degenerative changes, evaluation of spinal stenosis
- 3D images
- White colors = hyper dense
- Black colors = hypodense
16
Q
What is an MRI/MR (magnetic resonance imaging)
A
- non-ionizing
- based on measurements of energy emitted from hydrogen nuclei, energy emitted varies due to tissues, this allows MRI/MR to distinguish between different tissues
17
Q
T1 weighted image versus T2 weighted image (MRI/MR)
A
- T1: best for anatomical localization (measures energies rapidly & early), high water content areas appear darker, picks up adipose tissue & bone bone marrow well
- T2: best for contrasting normal & abnormal tissue (measures energies slow & late), high water content areas appear bright (fluid, edema, CSF, cysts, abscess, tumors, acute hemorrhage), excellent at detecting inflammation (think H2O)
18
Q
Contraindications for an MRI/MR
A
- pacemakers (malfunction)
- aneurysmal clips
- metal/foreign bodies in the eye
- hardware
- large area tattoos
- cochlear implants
19
Q
Advantages of MRI/MR
A
- high quality images of the musculoskeletal system
- soft tissue trauma
- stage tumors
- internal joint derangement
- variations in bone marrow
20
Q
Disadvantages of MRI/MR
A
- claustrophobia
- poor imaging of cortical bone
- time consuming
- expensive
21
Q
Describe the different image planes
A
- Cross sectional imaging = 2D view of 3D image
- Axial = transverse, sliced horizontally
- Sagittal = from nose to back of head cut
- Coronal = frontal, slice down the middle separating front from back
22
Q
Describe radionuclide bone scan (Scintigraphy)
A
- nuclear medicine is a specialty that uses radiopharmaceutical for diagnosis, therapy, & research (moderate radiation dosage)
- injection of radioactive tracers and a gamma or scintillation camera picks up the rays emitted to make an image
- info gained by viewing where & how much the radiopharmaceutical have concentrated in the body
- abnormal conditions = increased uptake of radiopharmaceutical
- normal bone appears transparent/gray except for growth plates & SI joint
- “hot spots” are black or white areas indicative of increased metabolic activity
- highly sensitive test but poor specific test
23
Q
Advantages and disadvantages of a bone scan
A
- Pros: cheap, most valuable in confirming the presence of disease & demonstrating the distribution of disease in the skeleton
- Cons: not specific, requires injection
24
Q
Describe sonography/ultrasound
A
- production of anatomic images using sound waves
- reflected sound waves are detected & serve as a basis for the image
- produces a cross sectional image
- used to view: Soft tissue pathology (tendon, muscle), Assessment of hematoma, abscess, foreign body, Articular cartilage defect, Fracture healing, Nerve entrapment
25
Q
Advantages of ultrasound/sonography
A
- demonstrates the soft tissue well
- low cost
- portable/convenient
- non-ionizing
- dynamic
- no radiation
26
Q
Disadvantages of ultrasound/sonography
A
- skill of operator
- superficial
- limited view
- obesity obstructs view
27
Q
Describe a DEXA scan
A
- DEXA = dual energy X-ray absorptiometry (low dose X-ray, 2 energies)
- preferred way to measure bone mineral density & body composition
- calculates a T and Z score
- T score = BMD compared to a healthy young adult of the same gender
- Z score = BMD compared to a peer age group of the same gender
- Normal T score = within 1 standard deviation from young adult
- T score 1-2.5 SD below the mean = osteopenia (low bone density)
- T score >2.5 SD below the mean = osteoporosis
28
Q
Indications for a DEXA scan
A
- osteopenia on X-ray
- height loss >2.5”
- metabolic disorder
- chronic disease
- hormone replacement
- non-traumatic vertebral fracture in postmenopausal female
29
Q
Describe interventional techniques
A
- Vascular procedures: angioplasty, vascular stenting, thrombolysis/thrombectomy, chemotherapy
- Non-vascular procedures: biopsies, abscess drainage
30
Q
Interventional techniques for musculoskeletal system
A
- Epidural steroid injections
- Spinal nerve blocks with fluoroscopy
- Radiofrequency ablation
- Percutaneous diskectomy
- Vertebroplasty/kyphoplasty
31
Q
What are epidural steroid injections used for
A
- used to relieve pain in patients with spinal stenosis, disk herniation, or intractable neck or back pain of uncertain cause by decreasing nerve root inflammation & swelling at the nerve-disk interface
32
Q
What are nerve blocks used for
A
- used for therapeutic or diagnostic purposes
- diagnostically are helpful in identifying the source of radicular pain
- once identified, blocking the transmission of pain via administration of an anesthetic to it, therapeutic steroids are then administered
33
Q
Describe radiofrequency ablation (RFA)
A
- RFA is the selective destruction of nerve tissue to treat chronic pain disorders
- the procedure involves thermal ablation from radio waves applied to the nerve via placement of a needle electrode under imaging guidance
34
Q
Describe vertbroplasty
A
- Vertbroplasty: an image guided injection of bone cement into the vertebral body to relieve intractable pain in patients with osteoporotic compression fractures
35
Q
Improper use of imaging
A
- unnecessary imaging can cause harm
- scan to abdomen/pelvis, chest, & head
- 1/3 projected cancers for people aged 35-54
36
Q
Radiation dosage for bone
A
- Spine X-ray: 6 mo comparable to natural background radiation
- Extremity (hoot, foot, etc.) X-ray: 3 hrs comparable to natural background radiation
37
Q
Radiation dosage for CNS
A
- CT of the Head: 8 mo comparable to natural background radiation
- CT for the Head repeated w/o contrast: 16 mo
- CT of the Spine: 2 yrs
38
Q
CT radiation dosages
A
- Head: equal to 30 chest X-rays
- Neck: 55
- Suspected Stroke: 199
- Chest: 117
- Coronary Angiogram: 309
- Abdomen: 220
- Multiphase Abdomen/Pelvis: 442
39
Q
3 components that define PT scope of practice
A
- Professional
- Personal
- Legal
40
Q
Describe a PT’s professional scope
A
- practice that is grounded in the profession’s unique body of knowledge supported by educational preparation based on a body of evidence and linked to existing or emerging practice frameworks
41
Q
Describe a PT’s personal and legal scope
A
- Personal: activities for which a person is educated and trained to completely perform; continuing education
- Legal: state practice at and statutes; professional board sets rules
42
Q
States that don’t include use of roentgen rays (radiology) and radioactive materials (radium) for diagnosis and therapeutic purposes
A
-VA
- AK
- CA
- CT
- FL
- KS
- KY
- LA
- NH
- OH
- OK
- TX
- WA
- WV
43
Q
Clinical hypotheses where suspected positive imaging findings would require urgent medical care
A
- Suspected acute fracture
- Critical region stress fractures
- Dislocations
- Complete muscle tears
- Progressive neurological deficit
- Stroke
- Infection
- Vascular condition (DVT, pulmonary embolism, abdominal aortic aneurysm - AAA)
- Prior history of cancer with constitutional signs
44
Q
Information to provide in a physical therapy referral for imaging
A
- Pt name and contact info
- Referring PT name & contact info
- Brief clinical summary detailing need for imaging (MOI, anatomical location, & results of essential clinical tests, brief results from prior imaging studies)
- Hypothesized clinical diagnosis
- Study being requested
- Statement on urgency or results if needed sooner than routine reporting timeline
45
Q
When is PT referral for imaging not warranted
A
- Pos. imaging results would indicate need for urgent medical care & follow up medical care is not readily accessible
- Referral for imaging to external facility would delay timely course of care
- Condition or body region of interest is outside the PT scope of practice
46
Q
When is PT referral for imaging warranted
A
- PT is located within a health system which can expedite medical care for findings requiring urgent medical care w/o delay in care
- Client condition is non-emergent & imaging results will not require urgent medical care
