Pitfalls of MRI in Spondyloarthritis
Pitfalls of MRI in Spondyloarthritis Pitfalls of MRI in Spondyloarthritis
Pitfalls of MRI in Spondyloarthritis Dr Alex Bennett FRCP PhD Consultant Rheumatologist Headley Court Visiting Senior Lecturer University of Leeds
- Page 2 and 3: ASAS classification criteria for ax
- Page 4 and 5: Conforming with Widely Held but oft
- Page 6 and 7: Don’t be a Lemming
- Page 8 and 9: Make friends with your radiologist!
- Page 10 and 11: Protocol & Sequences • Whole Spin
- Page 12 and 13: 25% AS patients SPINAL BUT NO ACTIV
- Page 14 and 15: Scan planning
- Page 16 and 17: Inflammatory Lesions T1w STIR
- Page 18 and 19: Mis-diagnosis
- Page 20 and 21: ASAS definition of “positive MRI
- Page 22: Differential Diagnosis: Septic Sacr
- Page 26 and 27: Spine
- Page 28 and 29: Differential Diagnoses A B C Degene
- Page 30 and 31: Septic Discitis v Spondylodiscitis
- Page 32 and 33: Artefact mimicking spinal lesions i
- Page 34: Artefacts • Coil effect - Spuriou
- Page 37 and 38: MRI Inadequacies
- Page 39 and 40: Disease Idiosyncrasies
- Page 41 and 42: “Negative” MRI NOT necessarily
- Page 43: Thank You
<strong>Pitfalls</strong> <strong>of</strong> <strong>MRI</strong> <strong>in</strong> <strong>Spondyloarthritis</strong><br />
Dr Alex Bennett<br />
FRCP PhD<br />
Consultant Rheumatologist Headley Court<br />
Visit<strong>in</strong>g Senior Lecturer University <strong>of</strong> Leeds
ASAS classification criteria for axial SpA<br />
(chronic back pa<strong>in</strong> >3 months, age at onset
<strong>Pitfalls</strong><br />
Conform<strong>in</strong>g with widely held but <strong>of</strong>ten <strong>in</strong>correct beliefs<br />
Request<strong>in</strong>g the Wrong Scans<br />
Mis-Diagnosis<br />
Technical Errors<br />
<strong>MRI</strong> <strong>in</strong>adequacies & Disease idiosyncrasies
Conform<strong>in</strong>g with Widely Held but<br />
<strong>of</strong>ten <strong>in</strong>correct Beliefs
The Radiologist is Always Right!<br />
What the **** is<br />
this?!<br />
This is an obvious<br />
case <strong>of</strong><br />
degenerative<br />
disease<br />
The request<br />
mentioned<br />
someth<strong>in</strong>g called<br />
Spondyloarthitis!?!
Don’t be a Lemm<strong>in</strong>g
Assume Noth<strong>in</strong>g
Make friends with your radiologist!
Request<strong>in</strong>g the Wrong Scan!
Protocol & Sequences<br />
• Whole Sp<strong>in</strong>e<br />
•4 sequences<br />
• cervico-thoracic – T1 and STIR<br />
• thoraco-lumbar – T1 and STIR<br />
•Sagittal only (to <strong>in</strong>clude pedicles and facets)<br />
• SIJs<br />
• 2 sequences<br />
• coronal oblique T1 and STIR<br />
• Contrast Not Required
35% AS<br />
38% axial-SpA<br />
NO ACTIVE <strong>MRI</strong> SACROILIITIS
25% AS patients<br />
SPINAL<br />
BUT NO<br />
ACTIVE SIJ LESIONS<br />
Images courtesy <strong>of</strong> Dr Alexander Bennett
Thoracic sp<strong>in</strong>e<br />
most<br />
sp<strong>in</strong>al lesions
Scan plann<strong>in</strong>g
Posterior Element Lesions<br />
STIR<br />
STIR
Inflammatory Lesions<br />
T1w<br />
STIR
Fatty Lesions<br />
T1w<br />
T1w
Mis-diagnosis
Sacroiliac Jo<strong>in</strong>ts
ASAS def<strong>in</strong>ition <strong>of</strong> “positive <strong>MRI</strong>”<br />
1. Sieper J et al. Ann Rheum Dis 2009;68:ii1-ii44
“Positive <strong>MRI</strong>”<br />
STIR<br />
STIR<br />
One slice sufficient<br />
2 slices required<br />
Image from ASAS handbook
Differential Diagnosis: Septic Sacroiliitis<br />
T1SE<br />
STIR
Differential Diagnosis: Insufficiency Fracture<br />
STIR<br />
T1SE
Sp<strong>in</strong>e
ASAS Def<strong>in</strong>ition <strong>of</strong> a Positive Sp<strong>in</strong>al <strong>MRI</strong><br />
• Inflammatory Romanus/corner lesions:<br />
• Fatty Romanus/corner lesions:<br />
≥2<br />
≥3<br />
• Posterior element lesions?<br />
ASAS Def<strong>in</strong>ition <strong>of</strong> a positive Sp<strong>in</strong>al <strong>MRI</strong>-In press
Differential Diagnoses<br />
A<br />
B<br />
C<br />
Degenerative Disease SpA Metastases<br />
Images courtesy <strong>of</strong> Dr Alexander Bennett
Septic Discitis v Spondylodiscitis<br />
T1<br />
STIR
Septic Discitis v Spondylodiscitis<br />
T1<br />
STIR
Degenerative Disease v Spondylodiscitis<br />
T1<br />
STIR
Artefact mimick<strong>in</strong>g sp<strong>in</strong>al lesions <strong>in</strong> SpA:<br />
haemangioma<br />
T1SE<br />
STIR
Technical Glitches
Artefacts<br />
• Coil effect<br />
– Spurious high signal at the lower SIJs<br />
• Anatomical artefact<br />
– Phase encod<strong>in</strong>g artefact – adjacent structures<br />
– Mimics – subchondral blood vessels
Phase-encod<strong>in</strong>g artefact : blood flow<strong>in</strong>g through great vessels<br />
T1SE<br />
STIR
<strong>MRI</strong> Inadequacies
HISTOPATHOLOGY v <strong>MRI</strong><br />
V<br />
8<br />
3<br />
Appel H et al. Arthritis Res Ther 2006
Disease Idiosyncrasies
Fluctuat<strong>in</strong>g Disease<br />
21%<br />
Basel<strong>in</strong>e<br />
12 months<br />
46%<br />
7%<br />
Marzo-Ortega, ARD 2009<br />
Basel<strong>in</strong>e<br />
12 weeks<br />
26%<br />
Stone et al, Rheumatology 2008<br />
Images Courtesy <strong>of</strong> Pr<strong>of</strong> J Sieper
“Negative” <strong>MRI</strong><br />
NOT necessarily<br />
“Normal” <strong>MRI</strong>
Summary<br />
Conform<strong>in</strong>g with widely held but <strong>of</strong>ten <strong>in</strong>correct beliefs<br />
Request<strong>in</strong>g the Wrong Scans<br />
Mis-Diagnosis<br />
Technical Errors<br />
<strong>MRI</strong> <strong>in</strong>adequacies & Disease idiosyncrasies
Thank You