4. Comparison of Relevant Modalities
Radiography CT US MR
Source Planar X-ray Rotating X-ray Ultrasound
Magnetic field &
Radiogrequency
Mechanism
X-ray penetration
through biological
material
X-ray penetration
through biological
material
Ultrasound reflection
on tissue interface
Excitation of hydrogen
proton to induce signals
Role Initial/Primary Secondary Secondary Secondary
Cost Low High Relatively low High
Radiation Relatively low Relatively high None None
Advantage
Better cost
effectiveness
Widely available
Highly accurate
Superior on cortical
& complex bones
Easy to perform
Superior on joint & soft
tissue
Superior for soft tissue,
joint & bone marrow
Limitation 70% sensitivity Higher radiation dose
Poor resolution on
deep structures
Operator dependency
Longer time exam,
claustrophobia,
pacemaker
36. Stress Fracture
•Mismatch of bone strength
& chronic mechanical stress
placed upon the bone
•Fatigue (march) fracture :
abnormal stresses on
normal bone
•Insufficiency fracture :
normal stresses on
abnormal bone, mostly due
to osteoporosis
42. ... but the most important:
•type of fracture
•intraarticular or not
•relationship between fragments
•relationship with surroundings
•critical structures nearby: neurovascular
•second (other) abnormalities
60. Complex Bone: Spine
•Jefferson: fracture of atlas
(C1)
•Odontoid: fracture of dens
•Hangman: fracture of pars
interarticularis C2
•Spondylolysis: fracture of
pars interarticularis
61. Complex Bone: Spine
•Jefferson: fracture of atlas
(C1)
•Odontoid: fracture of dens
•Hangman: fracture of pars
interarticularis C2
•Spondylolysis: fracture of
pars interarticularis
62. Complex Bone: Spine
•Jefferson: fracture of atlas
(C1)
•Odontoid: fracture of dens
•Hangman: fracture of pars
interarticularis C2
•Spondylolysis: fracture of
pars interarticularis
63. Complex Bone: Spine
•Jefferson: fracture of atlas
(C1)
•Odontoid: fracture of dens
•Hangman: fracture of pars
interarticularis C2
•Spondylolysis: fracture of
pars interarticularis
100. Key points
•Emergency setting : far from ideal
•Reason for imaging
•What is the information do you need?
•Is there any clinical confusion in terms
of diagnosis & management?
101. How to obtain maximum
benefit?
•Well-prepared patients
•Good relationship between
clinicians & radiology
•Clear & completely-filled
request form
•Direct communication
GARBAGE IN
GARBAGE OUT