knee mri pitfalls
Post on 17-Jan-2017
84 Views
Preview:
TRANSCRIPT
27.01.16
1
Radiology Research and Practice Center, Moscow
Pitfalls of knee MRI
Sergey Morozov, MD, PhD, MPH Irina Trofimenko, MD, PhD
Radiology Research and Practice Center, Moscow
Radiology Research and Practice Center, Moscow
Agenda
• Knee trauma diagnosis • Role of MRI • Multi-center trial of MRI effectiveness • Major pitfalls of MRI • Recommendations and regional
solutions
27.01.16
2
Radiology Research and Practice Center, Moscow
3
Clinical symptoms of knee injury
• Pain, limitation of movement • Hemarthrosis • Instability
→ Clinical Dx
Radiology Research and Practice Center, Moscow
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 20, No 7 (September), 2004: pp 696-700
Trained and experienced traumatologist has 100% accuracy in ACL tear diagnosis
Lachman test
Med. Men. Lat. Men. ACL
Clin. Dx MRI Clin. Dx MRI Clin. Dx MRI
Accuracy 80 80 92 90 100 98
Sens 87 80 75 85 100 96
Spec 68 79 95 97 100 96
27.01.16
3
Radiology Research and Practice Center, Moscow
5
MRI – preoperative verification of Dx
• MRI as predictor for arthroscopic treatment – Senc 79% – Spec 100%
Vincken et al. Radiology 2002; 223:739.
Strategy with MRI Strategy without MRI
Arthroscopy, % 57 92
Treatment costs 1296 961
Sick leaves, % 44 58
Sick days 11,8 15,8
Radiology Research and Practice Center, Moscow
Knee MRI dilemma
Lateral meniscus tear ACL tear
Sn 69,5 70 (55,2-84,7) Sp 94,5 94,5 NPV 80,5 59,6 PPV 90,5 96,5
Radiology 2002; 223:739–746
27.01.16
4
Radiology Research and Practice Center, Moscow
Sources of pitfalls
Technical
aspects
Normal
variants
Pathology
Radiology Research and Practice Center, Moscow
Purpose
• To analyze variability of preoperative knee MRI by means of retrospective multi-institutional study
27.01.16
5
Radiology Research and Practice Center, Moscow
Design of study
A
C
B
D
E
Arthroscopy (1 surgeon)
MRI centers
Traumatologist consultation
(3 physicians)
Retrospective analysis
Ortho General
1.5-3.0T A,E B
0.5-1.0T C D
Radiology Research and Practice Center, Moscow
Materials and Methods
% of patients with pathology at each MRI center
A B C D E Med. Meniscus 58,3 35,7 52,5 52,5 46,9
Lat. Meniscus 18,3 35,7 22,5 27,9 18,8
ACL 88,3 81,0 87,5 86,9 84,4
Cartilage 51,7 85,7 55,0 67,2 62,5
• 203 patients • 15-74 y.o. (35.0 ± 12.7 years) • Difference in age among diagnostic
centers - NS 43,30%
56,70%
male female
p<0.05
27.01.16
6
Radiology Research and Practice Center, Moscow
Materials and Methods: study flow chart
1. Retrieval of data from MRI and arthroscopy protocols (203 patients; 35.0 ± 12.7 y.o.)
2. Standardization and systematization of data 3. Database management 4. Data analysis:
– Diagnostic effectiveness of MRI (relative to arthroscopy)
– ROC
5. MR images revision
Radiology Research and Practice Center, Moscow
Results: menisci
Medial meniscus
00,10,20,30,40,50,60,70,80,91
0 0,2 0,4 0,6 0,8 1
A B C D E
Lateral meniscus
00,10,20,30,40,50,60,70,80,91
0 0,2 0,4 0,6 0,8 1
A B C D E
AUC: 0.57-0.87
Significant difference between MRI centers for medial meniscus
AUC: 0.56-0.80
27.01.16
7
Radiology Research and Practice Center, Moscow
0,870,78
0,670,87
0,77
0 0,5 1 1,5
Sensitivity
A
B
C
D
E 0,760,38
0,790,85
0,76
0 0,5 1 1,5
Specificity
Medial meniscus: Significant difference in specificity of MRI between centers B and D
Results: medial meniscus
A
B
C
D
E
Radiology Research and Practice Center, Moscow
0,67
0,470,33
0,600,64
0 0,5 1 1,5
Sensitivity
Lateral meniscus: No significant difference between MRI centers
Results: lateral meniscus
A
B
C
D
E 1,00
0,890,94
0,920,89
0 0,5 1 1,5
Specificity
A
B
C
D
E
27.01.16
8
Radiology Research and Practice Center, Moscow
Results: anterior cruciate ligament
0
0,2
0,4
0,6
0,8
1
0 0,2 0,4 0,6 0,8 1
A B C D E0,750,86
1,000,75
1,00
0 0,2 0,4 0,6 0,8 1 1,2
0,470,82
0,770,49
0,59
0 0,2 0,4 0,6 0,8 1 AUC: 0.67-0.89
Significant difference between centers A, B, D
Sensitivity
Specificity
A B C D E
A B C D E
Radiology Research and Practice Center, Moscow
Example 1 MRI report: Partial tear of ACL
Arthroscopy: Full-thickness tear of ACL
27.01.16
9
Radiology Research and Practice Center, Moscow
Example 2
MRI report: Tear of posterior horn of MM
Arthroscopy: no tear of menisci
Radiology Research and Practice Center, Moscow
Sources of pitfalls
Technical
aspects
Normal
variants
Pathology
27.01.16
10
Radiology Research and Practice Center, Moscow
19
Incomplete MRI protocol
Radiology Research and Practice Center, Moscow
Flow artifacts
A>>P
• The same shape
as popliteal
vessels
• Strongly
depends on
phase encoding
direction H>>F
27.01.16
11
Radiology Research and Practice Center, Moscow
Flow artifacts • Solution 1 = change phase-encoding direction
frequency-encoding
phas
e-en
codi
ng
K-space
K-space center
• Solution 2 = PROPELLER/ BLADE reconstruction
• K-space center is oversampled → ↑SNR, ↑CNR
•↑ time of reconstruction, ↑SAR
Radiology Research and Practice Center, Moscow
Magic angle artifact
TE 20 ms
• ↑ SI at 550 relative B0
• Affects only structured collagen fibers (tendons, cartilage, menisci, ligaments)
TE 70 ms
B0
550
27.01.16
12
Radiology Research and Practice Center, Moscow
Magic angle artifact
TE 20 ms
• Only exists with short TE (< 37ms)
TE 70 ms
Radiology Research and Practice Center, Moscow
Inadequate fat suppression
• Mimics edema • Off-center or at the
edge of the coil • Solution = STIR
27.01.16
13
Radiology Research and Practice Center, Moscow
Inadequate fat suppression • Solution 1 = STIR
- tolerance to B0 and B1 inhomogeneity - ↓ SNR
• Solution 2 = SPAIR - combination of CHESS+STIR - uses adiabatic inverting pulse → ↓sensitivity to B1
- longer time than STIR • Solution 3 = DIXON
- ↓ insensitive to B0 and B1 inhomogeneity - increases minimal TR
Radiology Research and Practice Center, Moscow
Sources of pitfalls
Technical
aspects
Normal
variants
Pathology
27.01.16
14
Radiology Research and Practice Center, Moscow
Fatty synovial folds
• Mimics loose bodies at fat sat
• ↑SI at T1-WI
Radiology Research and Practice Center, Moscow
Lateral tibial plateau cartilage • Mimics
chondrocalcinosis
True chondrocalcinosis
27.01.16
15
Radiology Research and Practice Center, Moscow
Meniscal flounce
Mohancumar et al, AJR: 203
• Up to 5% of MM • Transient physiologic
distortion • Seen with knee flexed,
disappears with full extension
Radiology Research and Practice Center, Moscow
Lateral meniscus anterior horn
• Striated appearance = normal
• Isolated tears LMAH only 16% of all LM tears
27.01.16
16
Radiology Research and Practice Center, Moscow
Menisco-femoral ligament
• When MFL hyperplasia mimics PCL tear or bucket-handle meniscal tear
Radiology Research and Practice Center, Moscow
Menisco-femoral ligament / LM junction
• Mimics radial \ vertical tears
• Attention: Wrisberg rip (ACL tear)
Pseudo-tear True-tear
27.01.16
17
Radiology Research and Practice Center, Moscow
Medial meniscus: menisco-capsular injury
Menisco-capsular injury
Menisco-capsular recess
• Fluid SI between PHMM and capsule
• Recessus: fluid SI doesn’t reach both meniscal surfaces
Radiology Research and Practice Center, Moscow
Anterior transverse ligament
• Mimics LM anterior horn tear
27.01.16
18
Radiology Research and Practice Center, Moscow
Popliteus tendon
• PT / LM posterior horn interface mimic LM tear
Radiology Research and Practice Center, Moscow
Patella bi/tripartite
• Typical location SL pole
• 2% of population • D e g e n e r a t i v e
remodelling
27.01.16
19
Radiology Research and Practice Center, Moscow
Patella dorsal defect
Patella dorsal defect Chondromalacia 4 grade
• Subchondral bone irregularity with intact overlying cartilage
Courtesy of Dr. D. Zimmermann Stefani (Radiopaedia.org )
Radiology Research and Practice Center, Moscow
Haematopoetic bone marrow • Red bone marrow
mimics edema or infarction
• ↑ SI than muscle on T1-WI
• Signal drop at opposed phase images
27.01.16
20
Radiology Research and Practice Center, Moscow
Sources of pitfalls
Technica
l aspects
Normal
variants
Pathology
Radiology Research and Practice Center, Moscow
Flap meniscal tear
normal pericapsular flap tear
Dandy DJ. The arthroscopic anatomy of symptomatic meniscal lesions. J Bone Joint Surg Br 1990; 72-B:628-633
• ~ 6% of meniscal tears
27.01.16
21
Radiology Research and Practice Center, Moscow
Root meniscal tear
• Often associated with meniscal extrusion
• 28% of MM tears
Bin SI et al Radial tears of the posterior horn of the medial meniscus. Arthroscopy. 2004 Apr. 20(4):373-8.
Radiology Research and Practice Center, Moscow
Chronic ACL tear
• Fibrotic tissue mimics ↓ SI of normal ligament
• Normal ACL = layered
27.01.16
22
Radiology Research and Practice Center, Moscow
Partial ACL tear
Radiology Research and Practice Center, Moscow
Postoperative ACL
• Graft made from harmstring tendon normally shows layered structure
• Mimics longitudinal tear
27.01.16
23
Radiology Research and Practice Center, Moscow
Iliotibial tract syndrom
• Frequently overestimated
Radiology Research and Practice Center, Moscow
Posterolateral corner injuries
• Frequently overlooked with ACL tears
27.01.16
24
Radiology Research and Practice Center, Moscow
Fat pad impingement
• Underestimated reason of anterior knee pain
Radiology Research and Practice Center, Moscow
Take home points
• Remember what is frequently missed: • Menisco-capsular junction injuries • ACL tears (multiplanar evaluation!) • Posterolateral corner injuries • Anterior fat pads impingement + Over-diagnosis of medial meniscus tears
27.01.16
25
Radiology Research and Practice Center, Moscow
Take home points
• Technical issues: • Check phase encoding direction • Choose appropriate fat suppression
technique • Remember the magic angle
• Anatomical issues: • carefully assess menisco-capsular junction
Radiology Research and Practice Center, Moscow
Major cause of MRI mistakes – lack of cooperation with orthopedic surgeons
27.01.16
26
Radiology Research and Practice Center, Moscow
Radiology Research and Practice Center, Moscow
27.01.16
27
Radiology Research and Practice Center, Moscow
Radiology Research and Practice Center, Moscow
Moscow RIS RIS installed in February 2015
• 63 out-patient departments
• CT 61
• MRI 40
• > 85000 studies
Second opinion
• 100 consultations per week
• 400 audits per week
• 3320 errors
Teaching
• 124 radiologists
• 97 technicians
www.rpcmr.org.ru
27.01.16
28
Radiology Research and Practice Center, Moscow
Conclusions – Standard imaging protocol – Correct interpretation (templates,
terminology, classifications) – Second opinion (PACS, RIS) – Cooperation with clinicians (MDT) – Teaching by radiologists and
traumatologists (focus: radiologists and technicians)
Radiology Research and Practice Center, Moscow
THANK YOU FOR YOUR KIND ATTENTION!
morozov@rpcmr.org.ru
www.rpcmr.org.ru
itrofimenko@emcmos.ru www.emc-school.ru
top related