MRI imaging of knee joint -- from radiological anatomy to pathology. inspired from my dear professor Mamdouh Mahfouz, professor of radio diagnosis - Cairo university.

1. MRI OF THE KNEE JOINT
Hossam Massoud
National cancer institute
Cairo university
inspired from
Prof. Mamdouh Mahfouz
Prof. of Radiodiagnosis
Cairo University

2. Knee joint complaint
 Pain  Trauma
 Swelling  Osteoarthritis
Suspected pathology [previous Examination]
 Inflammation
 Tumors
MRI OF THE KNEE JOINT
INDICATIONS

5. Protocol of examination
• Axial T1 localizer
• Sagittal T1, PD, T2
• Coronal gradient echo, STIR
•If contrast is injected → Axial, Sagittal
and coronal T1 WIs
Scanning parameters
 4mm slice thickness 1mm inter slice gap
 Field of view [FOV] = 16cm

7. How to know the pulse sequence?!
T1/ PD T2 Gradient STIR

8. PD
T1 T2
PD

9. Structure or lesionsT2T1
Cortical bone
Menisci (medial ,lateral)
Ligaments (ACL,PCL,…)
Calcification
LowLow
Common MR appearances

10. Common MR appearances
Fat (subcutaneous,
lipoma,…)
Bone marrow
LowHigh
Fluid (effusion, cyst,
ganglion)
HighLow
Blood
(heamoarthrosis)
HighHigh
T1 T2

11. Kinematic MRI

13. Where?!Items to be evaluated
Sagittal PD
Sagittal PD
Coronal
Axial
Sagittal PD
Sagittal T1& T2
Sagittal T2
Menisci (medial & lateral)
 Ligaments
- Cruciate (ACL, PCL)
- Collateral
- Retinacular
 Tendons ( Quadriceps,Pattelar)
 Bones
 Synovial effusion

14. Meniscus
 Medial meniscus
Banana- shaped
Posterior horn wider,
longer, taller than anterior
horn
Posterior horn tightly
attached to the capsule
Grade II degeneration
more common

15. Menisci
 Lateral meniscus
C- shape
Posterior and anterior horns are symmetric
Anterior horn may be hypo plastic, extremely thin
Discoid meniscus and meniscal cysts more common

17. AC
B
A B C

18. Lateral meniscus

19. Medial meniscus

21. Medial & lateral menisci

22. Cruciate ligaments

28. Patellar retinacular ligaments

29. Meniscus:

30. Meniscus:

31. Meniscal Lesions
 Tear
 Degeneration
 Cyst
 Discoid

32. Simple Tear
Complex Tear

33. Types of Meniscal degeneration
 Grade I
 Grade II
 Meniscal fraying

34. Tear

35. Tear

39. Meniscal degeneration with free edge fraying

40. Meniscal degeneration with free edge fraying

41. Types of Meniscal Tears
 Simple
 Complex
 Special types

42. Simple Meniscal Tears
 Horizontal
 Vertical
 Radial

43. Horizontal tear

44. Horizontal tear

45. Horizontal tear

46. Horizontal tear

47. Horizontal tear

48. Vertical tear
Occurs typically in the outer 1/3 of the
posterior horn or body of the meniscus
[ rare in the anterior horn ]

50. Vertical tear

51. Vertical tear

52. Radial tear
Vertical tear of the free edge of the meniscus [ Root tear ]
Ghost meniscus

53. Ghost meniscus
If there is no history of
Meniscal surgery and
the posterior horn is
absent near the
intercondylar notch

54. Special Meniscal Tears
 Flap
 Bucket handle
 MC separation

55. Flap tear [Oblique ]
Should have tow components , horizontal and vertical
Common in the medial meniscus
Fish mouth

58.  Decreased height , Free piece
 Small sized posterior horn
 Medially displaced fragment
 Double post. Cruciate ligament sign

59. Bucket Handel tear

60. Bucket Handel tear
Small sized posterior horn [ sagittal ]
Medially displaced fragment[ coronal]
Double PCL sign [ sagittal ]

61. Bucket Handel tear

64. Flipped meniscus : Double Delta Sign
Bucket Handel tear , Lateral meniscus

65. Flipped meniscus : Double Delta Sign

66. Discoid meniscus
Dysplastic meniscus with loss of normal semi lunar shape.
50% or more coverage of the tibial plateau.
Meniscal body segment seen in 3 or more sagittal images

68. Discoid meniscus

69. Discoid meniscus

70. Meniscal cyst
A Cyst extending from a meniscal tear
Common sites : Anterior horn LM , Posterior horn MM

74. Ligamentous
Lesions
 ACL
 PCL
 Collateral
 Retinacular

75. Anterior cruciate ligament

76. Anterior cruciate ligament

78. Primary signs [ In the ligament ]
Total discontinuity
Abnormal signal
Abnormal configuration
Abrupt angulation
Wavy appearance
Abnormal axis
Anterior cruciate ligament injury

81. Secondary signs [ Outside the ligament ]
• Bone contusions [Pivot- shift bruises ]
• Anterior translocation of the tibia
• Uncovered meniscus sign
• Avulsion fracture of the tibial insertion
• Segond fracture 70-100% with ACL tear
• PCL buckling
• PCL line sign
Anterior cruciate ligament injury
Hyperextension ACL tear with
"kissing bone bruises."

82. *
Anterior tibial translocation

83. Anterior tibial translocation with” uncovered meniscus sign”

84. Segond fracture
An elliptical vertically 3x10mm bone
fragment parallel to the lateral tibial
cortex, about 4mm distal to the plateau.
Best seen on AP or tunnel
radiographic views
75 -100% association with ACL tear

85. Segond fracture in patient
with ACL tear. T1- weighted
coronal MRI shows a small, low-
signal elongated fracture
fragment that is parallel to the
lateral tibia. The association of
Segond fractures with ACL
tears approaches 100%.

86. ?
Intraligamentous ganglion cyst

87. Posterior cruciate ligament
 The major stabilizer of the knee
 Uniform low signal , no striations
 Twice strong as the ACL
 The menisco-femoral ligaments are intimately
related to PCL. They connect the posterior horn
of the lateral meniscus to the medial femoral
condyle
Ligament of Humphrey anterior to PCL
Ligament of Wrisberg posterior to PCL

88.  PCL injuries represent about 12% of knee injuries
 Combined PCL injuries represent 97%
With ACL 65%
With MCL 50%
With MM 30%
Posterior cruciate ligament
TYPES OF PCL INJURES
Complete tear 40%
Partial tear 55%
Avulsion tear 7%

89. NORMAL PCL
TORN PCL
MR FINDINGS
Increased signal due to
hemorrhage and edema
Diffuse enlargement of PCL

90. COMPLETE PCL TEAR

91. NORMAL PCL
AVULSION TEAR
• Involves the tibial insertion
• Retracted bone fragment
• Bone marrow edema at avulsion site
• The actual PCL may be normal

92. AVULSION PCL TEAR

93. Collateral ligaments
MCL is about 8-11 cm
LCL is about 5-7 cm
Isolated injuries are rare,
usually with ACL and MM

94. Collateral ligaments
Grade I : microscopic tear
Grade II :partial tear
Grade III : complete tear
GRADING SYSTEM
Grade I,II and isolated grade III are treated conservatively,
while grade III tears associated with ACL tears are treated by
repairing ACL only

95. Proton density coronal image
shows the normal medial
collateral ligament as a thin,
taut, well-defined, low-signal
structure extending from the
medial femoral epicondyle to
the medial tibial metaphysis

96. Grade I medial
collateral ligament tear
with surrounding
edema (straight
arrows) on a T2WI
Note the normal
thickness and signal of
the medial collateral
ligament and continued
close apposition to the
femoral and tibial
cortices.

97. Grade II medial collateral ligament tear seen on a coronal
proton density image shows slight thickening of the medial
collateral ligament and separation from the underlying
cortices. Bone marrow edema of the lateral tibial plateau is
seen due to valgus stress
7 months after
conservative treatment

98. Grade II medial collateral ligament tear seen on a coronal T1 and
STIR images showing slight thickening of the medial collateral
ligament and separation from the underlying cortices.

99. Grade III medial
collateral ligament
tear on a coronal fast
spin-echo T2-weighted
image demonstrates a
disrupted ligament that
is thickened and
retracted with
surrounding edema
(black arrow).

100. Acute grade III tear with a folded ligament (arrow) and
surrounding edema on a coronal proton density image.

101. Acute tear of the proximal
portion of the lateral collateral
ligament is seen on this coronal
proton density image (white
arrow). Note the associated
grade II medial collateral
ligament tear.

102. ?
Grade III
MCL tear
with
retraction

103. ?
Grade III
MCL tear
with
abnormal
signal and
edema

104. Lateral pressure syndrome
 Thickening of the lateral retinaculum
 Lateral knee pain
 Obese, athletic patients
 May be associated with chondromalacia

105. Patella alta
 Sequlae of
patellofemoral
dysplasia
 Lengthening of the
infrapatellar tendon
 May be associated
with chondromalacia
 Length of patellar
tendon/ length of
patella > 1.3

106. Patella Baja
 Poliomyelitis
 Achondroplasia
 JRA

107. Pigmented villo-nodular synovitis
 Idiopathic
 Monoarticular disease 1% incidence
 Hypertrophic synovial masses with hemosiderin
laden macrophages bone erosions
 Intermediate signal in T1 and low signal in T2
with enhancement after contrast injection
 Typical location posterior to Hoffa’s fat pad
 Painless swelling , pain with progressive disease
 Treatment by synovectomy

108. PIGMENTED VELLONODULAR
SYNOVITIS

109. PIGMENTED VILLONODULAR SYNOVITIS

110. PIGMENTED VILLONODULAR SYNOVITIS
VERSUS LIPOMA ARBORESCENS

111. Pigmented villo-
nodular synovitis

112. POPLITEAL CYST
Fluid in the bursa which is usually
communicating with the joint space
Other names
Baker’s cyst
Gastrocnemius/semimembranosus bursa

113. Medial plica syndrome
 Inflamed synovial plica causing pain , crepitus
and pseudolocking
 Often in adolescents and athletics
 No measurement for plica thickness
Four types of plica
Suprapatellar 90%
Medial 15 -30%
Infrapatellar
Lateral [ rare]

114. PLICA SYNDROME

115. Knee pain with Normal MRI ?!
 Kinematic
 Meniscal contusion
 Plicae

116. Plicae
Anterior knee pain, clicking, locking
 Supra patellar, medial patellar, infrapatellar
 Medial patellar Plicae (Normal variant) 60% of
adult knee
Medial patellar Plicae

117. Supra patellar plica

118. Medial plica Syndrome

119. Osteochonddritis dissecans
 Osteochondral fragment in a typical location
 Young male
 Lateral aspect of the medial femoral condoyle
 Variable sized fragment attached or detached
 Criteria of unstable fragment
Large size more than 1cm
Fluid between the fragment and donor bone
Cystic changes at the donor site
Enhancement of the separation line

120. Osteochondritis Dissecans

121. OSTEOCHONDRITIS DISSECANS

122. OSTEOCHONDRITIS DISSECANS

123. Bone marrow contusion

124. Migratory osteoporosis

125. Bone infarcts
 Serpigenous lesions in the bone marrow
 Variable in size [ Chinese figures ]
 Double line sign is diagnostic [peripheral
hyperintense with hypointense inner border on T2
 CAUSES
POSTTRAUMATIC
STEROIDS
COLLAGEN DISEASES
ALCOHOLISM
PANCREATITIS
SPONTANEOUS

126. BONE INFARCTS

127. BONE INFARCTS

130. Quiz Cases

131. 1
23
4
56
7
8
Case 1

132. 1
2
Case 2

133. Case 3

134. Case 4

135. Case 5

136. 1
2
3
4
Case 6

137. Case 7

138. Case 8

139. Case 9

140. Case 10
1
2
3
4

141. Case 11

143. Case 12

144. Case 13

145. Case 14

146. Case 15

147. Case 16

148. Case 17

149. Case 17

150. Case 18

151. Case 19

152. Case 20

153. ACL TEAR
Case 21

154. Case 19

155. Synovial chondromatosis

159. Chondromyxoid fibroma