Diagnostic Imaging in Sports

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Diagnostic Imaging in Sports

• Christopher Meyering DO
• Director Sports Medicine
• DDEAMC Family Medicine Residency
• Fort Gordon, GA

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Objectives

• Review the various imaging modalities available
  to the sports clinician with an emphasis on
• indications
• limitations
• contraindications
• Describe abnormalities seen on radiographs to
  communicate effectively with specialty care
  clinicians
• Discuss fundamental imaging strategies for the
  evaluation of site-specific sports-related
  injuries

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Radiography

• Process by which x-ray beams are projected
  through a subject and onto an image detector
• Whiteness is a function of tissue radiodensity
  higher mass, higher attenuation, more white
• The image is a projectional map of the amount of
  radiation absorbed by the subject
• Analog detector systems
• Digital detector systems

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Radiography

• Readily available, inexpensive, serving as the
  initial imaging study after a sports-related
  injury
• Minimum of two-perpendicular views required
• Complex injuries may require additional views

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Minimum of Two Views
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Radiography

• Principal Indications in Sports Medicine
• Initial diagnostic image for musculoskeletal
  injuries
• Excellent for fractures,
  arthritis, bone tumors,
• skeletal dysplasia
• Stress maneuvers
• Follow-up of disease

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Radiography

• Advantages
• simple, readily available, inexpensive
• excellent spatial resolution
• real-time (fluoroscopy) availability
• Limitations
• radiation transmission
• relatively poor contrast resolution
• two-dimensional
• technician required
• Contraindications
• Poor soft tissue quality
• Pregnancy

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Computed Tomography

• CT uses x-rays to produce tomographic images
• The computer reconstructs images to produce a
  computed map
• Images are typically grayscale, with denser
  objects appearing lighter

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Computed Tomography

• The grayscale images can be modified or
  windowed to show only densities that appear in
  a certain range e.g. bone or lung
• Images can be reconstructed as 2D or 3D
• Helical/Spiral Ct capability volumetric data
  acquisition
• Kinematic CT allows for the imaging of joint
  motion

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Computed Tomography

• Principal Indications in Sports Medicine
• Complex fractures e.g. spinal and hip
• Abdominal trauma
• Closed head trauma

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Computed Tomography
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Computed Tomography

• Advantages
• Tomographic nature with higher contrast
  resolution of images
• Excellent images of bones and lungs
• Digital nature
• Wide availability
• Limitations
• Can produce artifacts motion and metal
• More limited soft-tissue contrast than MRI or
  ultrasound
• Contrast medium limitations
• Ionizing radiation
• Contraindications
• Limitations for obese patients
• Pregnant women should not have CT scans except in
  life-threatening emergencies

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Magnetic Resonance Imaging

• Based upon the number of free water protons
  within tissue
• Magnetic field aligns protons then a
  radiofrequency pulse deflects the alignment
• Termination of pulse causes realignment and
  energy emission

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Magnetic Resonance Imaging

• Principal Indications in Sports Medicine
• Unmatched ability to evaluate soft-tissue
  injuries
• Sensitive for bone marrow pathology
• Contrast agents may be utilized e.g. gadolinium

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Magnetic Resonance Imaging

• Advantages
• Superior contrast resolution, particularly among
  soft tissues
• High degree of sensitivity in diseases involving
  bone marrow
• Non-ionizing radiation
• Limitations
• Prone to artifact motion and metal
• Claustrophobia
• Specificity varies highly dependent upon
  interpretation
• Cost
• Contraindications
• Magnetic effects pacemakers, valves, pumps may
  malfunction
• Metal foreign bodies can migrate
• Tattoos and cosmetics can absorb heat

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Scintigraphy

• Triple phase bone scan
• The flow (perfusion) study - 60 seconds after
  injection
• Blood Pool - tissue vascularity and tissue
  perfusion
• Delayed - 2 -3 hrs after injection allows uptake
  into bone clearance from extraosseous tissues

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Scintigraphy

• Biologically active drugs (disphosphonates) are
  labeled with radioisotopes (technetium)
• The images produced by scintigraphy are a
  collection of radiation emissions obtained with a
  special camera (gamma camera)
• Two principal techniques in sports medicine
• Planar
• SPECT

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Scintigraphy

• SPECT
• Single Photon Emision Computed Tomography
• Enhanced tissue contrast
• Improved sensitivity and specificity of lesion
  detection/localization

Posterior planar
Axial
Coronal
Sagittal
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Scintigraphy

• Principal Indications in Sports Medicine
• screening for skeletal metastases, stress and
  occult fractures, osteomyelitis, and evaluation
  of focal bone tumors

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Scintigraphy

• Advantages
• Ability to image metabolic activity
• Exquisitely sensitive to fractures and tumor
• Limitations
• The lack of significant detail
• Poor spatial resolution
• Poor specificity
• Positive for up to one year
• Contraindications
• Patient exposed to ionizing radiation
• Children and pregnant women should be carefully
  screened

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Ultrasonography

• Ultrasound uses high-frequency sound waves to
  produce images
• Waves are transmitted to the patient, and
  reflected back by different tissues, with a
  computer synthesizing a tomographic image

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Ultrasonography

• Echogenicity of a structure determines the
  brightness of an object
• High frequency transducers provide better detail
• Doppler ultrasound can be used to image motion

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Ultrasonography

• Principal Indications in Sports Medicine
• Used to define extent of injuries in
  musculoskeletal structures such as tendons and
  muscles
• Can also be used to define masses and in
  localizing foreign bodies

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Ultrasonography

• Normal Achilles Tendon

Chronic Tendonopathy
Blurring, thickening and loss of normal
architecture
Bright structure with longitudinally oriented
bundles
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Muscle Evaluation
Hematoma in gastrocnemius
Torn rectus femoris muscle
Dynamic evaluation of rectus femoris with
complete disruption
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Ultrasonography

• Advantages
• Noninvasive with no ionizing radiation
• Can demonstrate non-ossified structures
• Relatively inexpensive
• Portable
• Real-time, 3D, and motion capabilities
• Limitations
• Cannot image inside bone, as bone cortex reflects
  sound
• Small field of view
• Time consuming
• Highly operator dependent
• Contraindications
• Heating of sensitive developmental tissues in
  fetuses

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Brief Quiz

• A soldier has two months of worsening right lower
  leg pain, has a positive bone scan which shows a
  grade 2 stress fracture in the posteromedial
  distal tibial shaft. He rehabs the injury and
  begins to run again. 4 months later there is a
  rapid return of symptoms. An x-ray shows some
  chronic changes in the bone but nothing acute.

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Brief Quiz

• Which of the following is the best imaging
  modality to evaluate the bone?
• Repeat x-ray in 2 weeks
• Bone scan
• Ultrasound
• MRI of the lower leg
• CT scan of the lower leg

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Brief Quiz

• Which of the following is the best imaging
  modality to evaluate the bone?
• Repeat x-ray in 2 weeks
• Bone scan
• Ultrasound
• MRI of the lower leg
• CT scan of the lower leg

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Describing Fractures
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Describing Fractures

• Important to know how to describe fractures
• Documentation
• Communicate with other physicians
• Colleagues
• Specialists
• Ortho-speak

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Pre-reading Musculoskeletal Radiographs

• 1 Name, date, old films for comparison
• 2 What type of view(s)
• 3 Identify bone(s) joint(s) demonstrated
• 4 Skeletal maturity (physes growth plates)
• 5 Soft tissue swelling
• 6 Bones joints (fractures dislocations)

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What is a bony fracture?

• Disruption of a bones normal structure or
  wholeness
• Crack, break, or rupture in a bone
• There are many hows and whys to bony fractures
• Terms used to describe each are related

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Mnemonic OLD ACID

• O Open vs. closed
• L Location
• D Degree (complete vs. incomplete)
• A Articular extension
• C Comminution / Pattern
• I Intrinsic bone quality
• D Displacement, angulation, rotation

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O Open vs. Closed

• Open fracture
• AKA Compound fracture
• A fracture in which bone penetrates through skin
• Open to air
• Some define this as a fracture with any open
  wound or soft tissue laceration near the bony
  fracture
• Closed fracture
• Fracture with intact overlying skin

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L Location

• Which bone?
• Thirds (long bones)
• Proximal, middle, distal third
• Anatomic orientation
• E.g. proximal, distal, medial, lateral, anterior,
  posterior
• Anatomic landmarks
• E.g. head, neck, body / shaft, base, condyle
• Segment (long bones)
• Epiphysis, physis, metaphysis, diaphysis

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D Degree of Fracture

• Complete
• Complete cortical circumference involved
• Fragments are completely separated
• Incomplete
• Not fractured all the way through
• Only one cortex involved
• e.g Greenstick fracture

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A Articular Involvement

• Intra-articular fractures
• Involves the articular surface
• Dislocation
• Loss of joint surface / articular congruity
• Fracture-dislocation

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Comminution/ Pattern

• Transverse (Simple)
• Oblique (Simple)
• Spiral (Simple)
• Linear / longitudinal
• Segmental
• Comminuted
• Compression / impacted
• Buckle / Torus
• Distraction / avulsion

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Comminution/ Pattern

• Transverse

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Comminution/ Pattern

• Oblique (Simple)
• Spiral (Simple)
• Oblique in 2 view

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Comminution/ Pattern

• Linear / longitudinal / split

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Comminution/ Pattern

• Buckle or Torus Fracture

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Comminution/ Pattern

• Avulsion
• Distraction

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I Intrinsic Bone Quality
Normal
Osteopenia
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D Displacement/ Angulation/ Rotation

• Displacement
• Extent to which Fx fragments are not aligned
• Fragments shifted in various directions relative
  to each other
• Convention describe displacement of distal
  fragment relative to proximal

Oblique tibial shaft Fx proximal aspect of the
distal third laterally displaced
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D Displacement/ Angulation/ Rotation

• Angulation
• Extent to which Fx fragments are not anatomically
  aligned
• In a angular fashion
• Convention describe angulation as the direction
  the apex is pointing relative to anatomical long
  axis of the bone (e.g. apex medial, apex valgus)

R Tibia with a transverse fx distal aspect of the
proximal third apex lateral
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D Displacement/ Angulation/ Rotation

• Rotation
• Extent to which Fx fragments are rotated relative
  to each other
• Convention describe which direction the distal
  fragment is rotated relative to the proximal
  portion of the bone

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Displacement/ Angulation/ Rotation
PA view of rotated hip fx the greater trochanter
is perpendicular to the film
Normal Hip
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Salter Harris Fractures
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Other Signs of Fracture

• Periosteal Reaction

Callus formation/ Osteosclerosis
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Other Signs of Fracture

• Fat Pad sign

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Quick Quiz
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Quick Quiz

• Right 5th MT, metaphysis, transverse fx, with 5
  degrees of angulation, apex lateral
• Aka Jones fx

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Area Specific Imaging
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Acute Head Injury

• The general consensus is that CT scanning is the
  preferred imaging test of choice in the acute
  setting
• Ability to detect intracranial bleeding
• Ability to detect fractures
• Controversy on who needs a CT
• Prolonged loss of consciousness, focal neurologic
  sign, depressed level or worsening level of
  consciousness
• Skull X-ray is low yield

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Shoulder

• Acute Shoulder Trauma
• Impingement
• Instability

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Acute Shoulder Trauma

• Plain radiographs (5 views)
• True AP, and AP in internal and external rotation
• Transscapular and axillary views
• Complex fractures
• CT

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Impingement

• Plain radiographs
• AP, Axillary, Supraspinatus Outlet View
• 30o caudal tilt view
• AC AP with cephalic tilt
• MRI
• Tendinopathy
• AC arthropathy

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Instability

• Plain radiographs
• AP, True AP, Transscapular views
• West Point axillary view
• Stryker notch view
• Labral Pathology
• MRI with gadolinium
• CT arthrography

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Wrist

• Acute Wrist Injury
• Chronic Wrist Pain

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Acute Wrist Injury

• Standard views PA and lateral
• Scaphoid fracture
• scaphoid view if negative, immobilization for 2
  weeks, followed by repeat films if negative and
  symptomatic, limited MRI
• Hamate fracture
• carpal tunnel view if negative CT scan
• Scapholunate Dissociation Clenched fist view

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Chronic Wrist Pain

• Complex Regional Pain Syndrome
• Carpal Instability
• Dorsal Impingement Lesions

• TFCC Injury
• Occult Ganglion
• Hamate Fracture
• Keinbocks Disease

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Knee

• Acute Knee Trauma
• Chronic Pain/ Instability
• Patellofemoral

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Acute Knee Trauma

• AP, lateral, Tunnel view
• CT scan for complex fractures
• MRI

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Chronic Pain/ Instability

• AP, 30o flexion lateral, 4 5 deg weight bearing
  flexion PA, weight bearing AP on long cassette
• MRI
• Meniscal injury
• Ligamentous insufficiency
• Osteochondral injury

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Patellofemoral Pain

• AP, 30o flexion lateral, 45o weight bearing
  flexion PA, weight bearing AP on long cassete
• Axial merchant view
• Lateral patellofemoral angle
• angle should open laterally

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Ankle

• Acute Ankle Trauma
• Chronic Ankle Pain
• Chronic Ankle Instability

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Acute Ankle Injury

• AP, Lateral and Mortise views

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Chronic Ankle Pain

• Chronic ankle pain osteochondral lesions, occult
  fractures, impingement lesions, tendon problems
• MRI is thought to be the imaging modality of
  choice
• Some authors recommend bone scan for diffuse
  nonspecific pain, with a f/u CT if needed as
  provides superior bone resolution

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Chronic Ankle Instability

• Ankle instability series
• Anterior drawer gt 5 mm anterior translation
  compared with unaffected side
• Talar tilt gt 5- 1 0 degree variance compared
  to the contralateral side

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Conclusion

• Plain films are the initial diagnostic imaging of
  choice
• Base advanced imaging decisions upon clinical
  suspicions after a careful history and physical
  exam
• Consult radiologist or subspecialist for
  additional imaging concerns

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Posttest
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An appropriate indication for a CT is..

• Closed head trauma
• Assessment of ligaments
• A pregnant woman
• Simple fractures

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MRIs are best for.

• Occult fractures
• Soft-tissue injuries
• Evaluating metabolic activity
• Claustrophobic welders with AICDs

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In describing a fracture, rotation means

• Extent to which Fx fragments are rotated relative
  to each other
• Position of the body during the fracture
• A fracture in which bone penetrates through skin
• A move in Twister

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Which view is best for evaluating initial knee
trauma?

• Sunrise view
• Weightbearing
• AP, lateral, Tunnel view
• West Point View