shoulder mri for surgeons
DESCRIPTION
It is not uncommon to receive ambiguous and incorrect imaging reports from radiologists. There are numerous reasons for this, such as poor clinical information, differential experience, imaging protocols, etc. As there is no unified protocol for MRI sequencing reports are limited by these factors. Studies have also shown that there is poor agreement on scan interpretation, with experienced surgeons being more accurate than radiologists, as they can better correlate the imaging with the clinical information. There is a lot of mystique and misunderstanding around MRI imaging and many surgeons find it confusing. In this lecture I will provide some of my tips and experience in understanding MRI scanning for the surgeon and clinician.TRANSCRIPT
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Lennard Funk
1
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• Prof. Waqar Bhatti
2
• Dr. Jonathan Harris
• Dr. Sarah Jackson
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QUIZ
3
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QUESTION A
My IDEAL investigation for cuff pathology
is:
a. Ultrasound
b. MRI
c. MR Arthrogram
d. CT Arthrogram
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QUESTION B
My IDEAL investigation for Instability is:
a. Ultrasound
b. MRI
c. MR Arthrogram
d. CT Arthrogram
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QUESTION 1
Radiologists are better at interpreting MRI scans than surgeons:
a. True
!b. False
6
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QUESTION 2
MRI Sequences:
a. T1 is best for pathology
b. In T2 fat tissue is bright
c. A long TR is shows inflammation
b. STIR is a Fat Suppression sequence
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QUESTION 3
MR Arthrogram:
a. ABER improves accuracy
b. Cannot show Bony lesions
c. Is not ideal for fatty infiltration
d. Is 100% accurate for labral tears
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MRI
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AMBIGUOUS REPORTS
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“Full width tear”
“Advanced muscle atrophy along with Infraspinatus”
“mild atrophy supraspinatus”
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CONFUSING REPORTS
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There is a partial full tear of the supraspinatus tendon.
There is a complete partial tear of the supraspinatus tendon.
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INADEQUATE SCANS
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Grainy Shadows
Movement
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CUFF PATHOLOGY IN ASYMPTOMATIC
• 96 MRI’s viewed by 2 radiologists
• 20% PTT; 15% FTT
– Increased with age:
• >60yrs = 55% PTT; 30% FTT
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Sher et al. JBJS. 1995
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MR ARTHROGRAM V. SCOPE
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Sensitivity Specificity Accuracy
SLAP 0.42 0.92 77%
Rotator Cuff Tear 0.50 0.86 83%
Hill Sachs 0.91 0.78 90%
Bankart 0.85 0.83 86%
N Karlson, J Geoghan, L Funk; 2008
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RADIOLOGIST LOCALITY
• Nine radiologists - regional & secondary care
• MR diagnostic accuracy is better when surgeon and radiologist work in the same institution.
• Differences between local- and non-local MRA data suggest that diagnostic accuracy is better in the local secondary referral centre.
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N Karlson, J Geoghan, L Funk; SECEC 2011
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DO NOT RELY ON THE SCAN REPORT
An experienced Shoulder Surgeon better Can correlate with clinical context Experience of reviewing Scopes & Scans
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MRI BASICS
• T1 - Fat Bright - Anatomy
• T2 - Water Bright - Pathology
• Standard 3mm thick slices
• Thick slices = more signal & less grainy, but lower spatial resolution (due to volume averaging)
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MRI BASICS
• PD = Long TR & Short TE
• T1 = Short TR & Short TE
• T2 = Long TR & Long TE
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• TE is always < TR
• Short TR < 500ms
• Long TR > 1500ms
• Short TE < 30ms
• Long TE > 90ms
http://www.imaios.com/en/e-Courses/e-MRI/MRI-signal-contrast/Signal-weighting
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MRI BASICS
• Fat Suppression
• PDFS
• T2 Gradient Echo
• STIR
• SPIR
• SPAIR
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• Labral Tears
• Bankart
• Perthes
• ALPSA
• SLAP
• GLAD
• GLOM
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T1 WI T2 FS
INFLAMMATION
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MUSCLE OEDEMA
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T1 FS T2 FS
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LABRAL TEARS
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T1 WI T1 FS
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PLAIN MRI SEQUENCES
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• Hospital 1:
• Hospital 2:
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MRI SEQUENCES
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• No universal standards
• Each Hospital has different MRI Protocols
• Each Radiologist has different experience
• Each clinical question demands different approach
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PLAIN MRI - PREFERENCES
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1. Full Series
!!2. T1 Axial - Bony Bankarts
3. T1 Sag - Bony Bankarts
4. T1 Sag - extend medial to scapula ‘Y’
5. T2 FS Cor - Cuff, ACJ, Bursa
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T1 WITH FS SAGITTAL IN GLENOID PLANE
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SCAPULA ‘Y’ ON T1WI
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ARTEFACT
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ARTEFACT
• Rotator cuff repair
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ARTEFACT
• ACJ Metalwork
• Deodorant spray in axilla
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MR ARTHROGRAM
• Direct / Indirect
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INDIRECT ARTHROGRAM
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INDIRECT ARTHROGRAM
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ABER
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ABER
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MR ARTHROGRAM
• Direct / Indirect
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SUMMARY
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• Beware / Be aware of Reports • Full 6 series • T1 FS Axial - Instability • T2 FS Cor - Rotator Cuff • T1 Sag to Scapula ‘Y’ • MRA:
– Direct – T1 FS in 2 planes (axial; sagittal) – ABER (if able)
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RELATIONSHIPS
• Clinical Imaging is a ‘request for consultation to clarify a clinical query’
• NOT ‘ordering’ an investigation
!• Vetting of request should be an MSK Radiologist
• Provide clear clinical info and query
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I can see it now !
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QUIZ
49
AMSTERDAM / THE NETHERLANDS
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QUESTION 1
Radiologists are better at interpreting MRI scans than surgeons:
a. True
!b. False
50
AMSTERDAM / THE NETHERLANDS
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QUESTION 2
MRI Sequences:
a. T1 is best for pathology
b. In T2 fat tissue is bright
c. A long TR is shows inflammation
b. STIR is a Fat Suppression sequence
AMSTERDAM / THE NETHERLANDS
www.esska-congress.org52
QUESTION 3
MR Arthrogram:
a. ABER improves accuracy
b. Cannot show Bony lesions
c. Is not ideal for fatty infiltration
d. Is 100% accurate for labral tears
AMSTERDAM / THE NETHERLANDS
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WWW.SHOULDERDOC.CO.UK
53
Full Time / Part Time
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