MRIs: Everyone Wants One,But… Who Needs One?
Megan M. May, MDAssistant ProfessorOrthopedic Surgery/Sports MedicineBaylor College of MedicineTexas Children’s Hospital
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Goals…
• Discuss specific conditionsfor which advanced imagingis indicated.
• Discuss which specificstudies are indicated forthese conditions.
• Provide tips on orderingappropriate studies.
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The Facts…
10% annual increasein # of MRIs performedfrom 1996-2010
Smith Bindman et al. JAMA 2012.
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Why Are We Ordering MRIs?
• Diagnosis?
• Rule out/Reassure?
• Patient satisfaction?
• Defensive medicine?
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Defensive Medicine
Costs
• 24% ordered fordefensive medicine
• $100,000/yr perorthopaedic surgeon(Sethi et al. Am J Orthop 2012.)
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What Can We Do to Decrease Cost?
1. Order the right study for the right reasons.
2. Refer to the right facility.
3. Refer to specialist if uncertain.
4. Be able to interpret images/report.
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Know what you’re looking for…
• Pathology in kids and adults is different
• History is important
• Clinical exam is important
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The Knee
History/Exam
• Mechanism of injury
‐ Acute vs. chronic
• Exam
‐ Effusion is key
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Importance of an Effusion
High School
• ACL tear (41%)
• Patellar dislocation (21%)
• Meniscus tear (12%)
Middle School
• Patellar dislocation (36%)
• ACL tear (22%)
• Meniscus tear (16%)
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Patellar Dislocation
Bone Bruises, MPFL Injury Loose Body
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Meniscus Tear
Posterior Horn Tear Radial and Horizontal Tears
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Osteochondritis Dissecans
Irregular Ossification OCD Lesion
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Osteochondritis Dissecans
Irregular Ossification OCD Lesion
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The Shoulder
Shoulder Dislocation
• History
‐ Acute Injury?
‐ Direction?
‐ Reduction?
‐ # of previous injuries
• Exam
‐ Apprehension test
https://vimeo.com/50708310
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The Hip
Labral Tear
• History
‐ Acute or chronic
• Exam
‐ Impingement test
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Spine
• History:
‐ Radicular pain below knee
‐ Bowel / bladder symptoms
• Exam:
‐ Positive straight leg raise
‐ Objective weakness
‐ Asymmetric abdominal reflexes
• Imaging:
‐ High-grade spondylolysis/listhesis
‐ Unusual scoliosis curve or rapid progression
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MR Lumbar Spine Without Contrast
Scoliosis X-ray Syrinx6 month interval
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Foot / Ankle
Never order MRI foracute ankle sprain
Consider
• Ankle sprain that does notimprove after good course ofRx (peroneal tendon injury)
• Osteochondral fracture
• Suspected stress fracture
• Tarsal coalition
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Tumors / Infections /Inflammatory Arthritis
• Always order with and without contrast
‐ Except osteochondromas — don’t usually need MRI,no contrast if ordered
• TCH – ”Fast” protocol for infections toavoid sedation
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Infection / Septic Arthritis
Septic Hip, Osteomyelitis
Tibia osteomyelitis,intraosseous abscess
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Tips on Ordering MRIs
• Scanner should be at least 1.5 T
• Open MRIs are bad
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Tips on Ordering MRIs
• Scanner should be at least 1.5 T
• Open MRIs are bad
• Children < 8 yo usually need sedation
• Hospital vs. outpatient scans
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In Conclusion…
• Know the facilities that you are referring to
‐ Cost
‐ Image quality
• Order contrast, arthrogram appropriately
• If unsure, refer