Diagnostic Imaging

• Origin of Imaging in Physical Therapy

  • Since 1970's, Military PT's have had imaging ordering privileges – model has demonstrated added value to the health care system
  • The APTA 2020 vision is for PT's to have the ability to order imaging within scope and level of expertise (APTA COE)
  • AAOMPT position regarding ultrasound imaging within the scope of physical therapist practice
• Wisconsin PT10 Rule


  • Became effective 8/1/17
  • Defines which PT's can order Radiographs
  • One of four qualifications must be satisfied to have xray ordering privileges
  • Qualification 1: PT holds entry level doctorate in physical therapy from accredited program
  • Other requirements include appropriate communication of results
• Professional Relevance


  • Military model dispels concerns
  • APTA Vision 2020 regarding x-ray is a reality in certain states
  • Point of care application of musculoskeletal ultrasound becoming more commonplace practice
  • Imaging instructional content mandated by accreditation
  • Licensure exam now integrates imaging content
• Radiologic Practice Areas


  • Interventional Radiology
  • Radiation Oncology
  • Diagnostic Imaging
• Diagnostic Imaging


  • Imaging for all body systems
  • Various imaging modalities
  • Examples: Cardiac, GI, Neurological, MSK, Vascular, Urologic, etc.
• Classifications of Diagnostic Imaging

  • Ionizing Radiation Imaging
  • Reflective Imaging
  • Emission (Nuclear) Imaging
• Conventional Radiography


  • Conventional Radiograph = "plain films" or "x-rays"
  • Form of ionizing radiation
  • Originally developed and viewed on "hard copy"
  • Being replaced by digitalized images
• Conventional Radiography


  • Usually first diagnostic study ordered
  • Serves as a basic assessment tool to screen for abnormalities
  • Excellent visualization of bone, calcifications, foreign objects
  • Often sufficient to obtain diagnostic answer and direct initial treatment
• 1. ray Production


  1. X-ray tube

  2. Patient

  3. X-ray film or image receptor

  4. X-rays produced in an x-ray tube via an energy conversion

  5. X-rays exit the tube and pass through the patient
• 1. ray Interaction


  • Scatter – x-rays scatter from the patient and other objects
  • Absorption – body absorbs x-rays and prevents x-ray from reaching film/detector
  • Transmitted – x-rays penetrate completely through body
• Image Production


  • X-ray image composed of x-rays that pass freely through the body and x-rays which have been absorbed or scattered by various body structures
  • Amount of absorption and scatter determined by thickness and density of a structure (radiodensity)
  • The greater the density of the structure = greater ability to absorb x-rays
  • The lower the density of the structure, = easier for x-rays to be transmitted or pass through the object
• Differences in tissue density are what is visualized on radiographs
• Tissues with less density appear darker
• Tissues with greater density appear lighter
• Image Production


  • When obtaining images, central x-ray (central ray) beam is focused on area of anatomic interest
  • Structures that need to be measured accurately are placed closer to the image detector
• The closer the patient to the detector

  The less magnification is produced
• Tissue Density


  • Air/Gas - Black
  • Fat - Dark Grey
  • Soft tissue/Water - Light Grey
  • Bone/ Calcification - White
  • Metal - Bright White
• Contrast Agents


  • Radiolucent contrast
  • Radiopaque contrast
  • Combination can be used
  • Contrast used in all areas of medicine (MS, Cardiology, GI, GU)
• Arthrography


  • Procedure that introduces contrast agent into a joint space
  • Most often performed in the wrist, shoulder, elbow and ankle
  • Images taken before and after contrast introduction
  • Can be used with plain films, CT or MRI
• Overexposure & Underexposure


  • When a film is overexposed it is too radiolucent and therefore too black
  • When a film is underexposed it is too radiopaque and therefore too white
• Advantages of Radiography


  • Rapid Results
  • Non-Invasive
  • Cost
  • Excellent definition of bone
• Disadvantages of Radiography


  • Ionizing Radiation
  • Contrast in bone density is limited (poor detection of stress frx, osteoporosis, infections)
  • Soft tissues poorly defined
  • 2D image of 3D structure
  • Superimposition
• ALARA


  • As Low As Reasonably Achievable
  • Why is there a reliance on imaging (at times)?
  • Driven by numerous factors
• Density


  Give an example of a Radiopaque structure
• # of Views


  • AP view
  • Lateral view
• What information can be gained from the image labels?
• Superimposition


  Identify superimposition on the adjacent Radiograph
• Commonly Missed Fractures


  • Failure to order radiography
  • Failure to recognize fractures on radiograph
  • Subtle fractures to untrained or less skilled clinician(s)
  • Presence of multiple Injuries, distracting injury
  • Inadequate pt history
• Commonly Missed Fractures of the Spine

  • C1
  • C2
  • C6
  • C7
  • Osteoporotic Fractures of Thoraco-Lumbar spine
• Commonly Missed Fractures in the LE

  • Hip
  • Patella
  • Calcaneus
  • Posterior Acetabulum
• Commonly Missed Fractures in the UE

  • Radial Head
  • Triquetrum
  • Distal Radius
  • Scaphoid Fractures
• Commonly Missed Fractures


  If high suspicion for fracture but Rads (-), how should this be managed?