MRI KNEE OF ORTHOPEDIC IMPORTANCE: AN OVERVIEW

1. PRESENTED BY: Dr. BEN
MRI KNEE OF ORTHOPEDIC
IMPORTANCE

2. MRI is based on the principle of nuclear magnetic resonance (NMR)
Two basic principles of NMR
1.Atoms with an odd number of protons or neutrons have spin
2.A moving electric charge, be it positive or negative, produces a magnetic field
Body has many such atoms that can act as good MR nuclei (1H, 13C, 19F, 23Na)
Hydrogen nuclei is one of them which is not only positively charged, but also
has magnetic spin
MRI utilizes this magnetic spin property of protons of hydrogen to elicit images
BASICS AND PRINCIPLES OF MRI

3.  Hydrogen nucleus has an unpaired proton which is positively charged
 Every hydrogen nucleus is a tiny magnet which produces small but
noticeable magnetic field
 Hydrogen atom is the only major species in the body that is MR sensitive
 Hydrogen is abundant in the body in the form of water and fat
 Essentially all MRI is hydrogen (proton) imaging
•In our natural state Hydrogen ions in body are
spinning in a haphazard fashion, and cancel all the magnetism.
•When an external magnetic field is applied protons in the body align in one
direction. (As the compass aligns in the presence of earth’s magnetic field)
SIGNIFICANCE OF HYDROGEN IN MRI

4. When RF pulse is stopped higher energy gained by proton
is retransmitted and hydrogen nuclei relax by two
mechanisms
T1 or spin lattice relaxation- by which original
magnetization (Mz) begins to recover.
T2 relaxation or spin spin relaxation - by which
magnetization in X-Y plane decays towards zero in an
exponential fashion. It is due to incoherence of H nuclei.
T2 values of CNS tissues are shorter than T1 values
CONCEPT OF T1 AND T2 IMAGING

5. TE (echo time) : time interval in which signals are measured after RF excitation
TR (repetition time) : the time between two excitations is called repetition time
By varying the TR and TE one can obtain T1WI and T2WI
In general a short TR (<1000ms) and short TE (<45 ms) scan is T1WI
Long TR (>2000ms) and long TE (>45ms) scan is T2WI
Long TR (>2000ms) and short TE (<45ms) scan is proton density image
HOW TO OBTAIN T1 AND T2
IMAGES?

6. Liquids: long T1 and T2 values
Fat: short T1 and T2 values

7. HYALINE CARTILAGE

8. ARTICULAR CARTILAGE

9. SAGITTAL
CORONAL
AXIAL
SEQUENCE OF EVALUATION

10. SAGITTAL VIEW

11. Vastus medialis
Medial gastrocnemius
Sartorius

12. Vastus medialis
Medial femoral condyle
Medial meniscus
Tibia
Medial
gastrocnemius
Gracilis tendon
Sartorius muscle

13. Vastus medialis
Medial femoral condyle
Medial meniscus
Tibia
Semitendinosus tendon
Medial
gastrocnemius
muscle
Gracilis tendon
Medial gastrocnemius
tendon

14. Posterior horn of medial meniscus
Joint capsule
Anterior horn of medial meniscus
Semimembranosus
tendon
Semitendinosus
tendon
Semimembranosus
muscle

18. Shaft of the tibia
Shaft of the femur

20. Infrapatellar fat pad
Patella
Oblique popliteal
ligament
Posterior cruciate ligament
Popliteus muscle

21. Posterior cruciate
ligament
Popliteal artery
Anterior cruciate ligament
Patellard tendon
Quadriceps tendon

22. Tibial nerve
Popliteal vein
Anterior cruciate ligament
Popliteal
artery
Popliteus muscle

23. Posterior horn of
lateral meniscus

24. Quadriceps tendon
Patella
Patellar tendon
Tibia
Femur

26. Popliteus muscle
Popliteus tendon
Posterior horn of
lateral meniscus
Head of fibula
Anterior horn of lateral meniscus
Lateral femoral condyle

27. Common
peroneal nerve
Lateral head of
gastrocnemius muscle
Biceps femoris muscle

28. Tendon of the lateral
head of gastrocnemius
Common peroneal
nerve
Lateral meniscus
Vastus lateralis muscle

29. Superior tibiofibular
joint
Tibialis anterior muscle

33. CORONAL VIEW

34. Biceps femoris tendon
Biceps femoris
Popliteal artery
Lateral head of
gastrocnemius muscle
Head of fibula
Semimembranosus
muscle
Gracilis
tendon
Semimembranosus
tendon
Medial head of
gastrocnemius
muscle
Semitendinosus
tendon

35. Lateral superior geniculate artery
Sartorius
muscle
Medial inferior geniculate
artery
Popliteal artery
Popliteus muscle
Biceps femoris tendon

36. Lateral femoral condyle
Great
saphenous
vein
Popliteus muscle

37. Lateral gastrocnemius tendon
Medial
gastrocnemius
tendon
Medial
femoral
condyle
Sartorius
tendon
Gracilis
tendon
Posterior cruciate ligament
Lateral tibial plateau
Semimembranosus
tendon
Medial tibial plateau
Great
saphenous
vein

38. Lateral meniscus
Head of the fibula

39. Anterior cruciate ligament
Lateral collateral ligament Medial collateral
ligament

40. Medial femoral
condyle
Lateral femoral condyle
Popliteus tendon

41. Lateral
intermuscular
septum
Anterior cruciate ligament
Lateral meniscus
Lateral intercondylar tubercle
Medial intercondylar tubercle
Posterior
cruciate
ligament

42. Vastus medialis muscle
Anterior cruciate ligament

43. Iliotibial band

45. Iliotibial band

46. Anterior horn of
medial meniscus

47. Infrapatellar fat pad
Vastus lateralis tendon

50. Lateral retinaculum

51. Patella
Lateral retinaculum
Infrapatellar fat pad
Patellar tendon
Medial retinaculum
Quadriceps tendon

54. AXIAL VIEWS

55. Tibial tuberosity
Saphenous nerve
Great saphenous vein
Medial gastrocnemius
Lateral gastrocnemius
Soleus
Tibia
Tibialis anterior
Fibula

57. Patellar tendon

63. Lateral tibial condyle
Iliotibial tract
Medial tibial condyle
Sartorius tendon
Gracilis tendon
Semitendinosus tendon
Semimembranosus tendon

68. Medial femoral condyle
Lateral femoral condyle
Infrapatellar fat pad Patellar tendon
Popliteus tendon

71. Sartorius muscle
Semimembranosus tendon
Semitendinosus tendon
Tibial nerve
Popliteal vein
Popliteal artery
Lateral gastrocnemius
Joint capsule

76. Superior medial geniculate artery
Superior lateral geniculate artery
Patella
Synovial fluid

78. Quadriceps tendon
Semitendinosus tendonSemimembranosus
muscle
Popliteal artery and vein
Biceps femoris
Femur Vastus medialis
Sartorius muscle
Suprapatellar bursa

79. BASIC SEQUENCES IN MSK MRI

80. Proton-density-weighted sequences: they produce images with the
highest signal-to-noise ratio and, therefore, provide better resolution
than T2-weighted FSE images. USEFUL FOR MENISCI,
CARTILAGE
T1-weighted images: produce high a signal-to-noise ratio, useful in
showing musculoskeletal anatomy. WORKHOUSE FOR ANATOMY.
Fat appear bright signal/white.
Gadolinium enhanced T1 with STIR determine presence of abscess
T2-weighted sequences: have the poorest signal-to-noise ratio, and
therefore the poorest resolution, but they are used primarily for their
fluid sensitivity and their ability to detect pathology that has a high fluid
content (e.g., tendon or ligament tears, tumors).
SIGNIFICANCE OF THE
DIFFERENT SEQUENCES OF MRI

81. The ability to depict anatomic detail, bone marrow
abnormalities (including marrow infiltrating
processes and fractures), meniscal pathology, blood
products, melanin, and enhancement after the
administration of gadolinium are the strengths of
T1- weighted SE sequences.
For the assessment of tumors or musculoskeletal
infection, fat-suppressed T1-weighted imaging
after gadolinium contrast administration represents
the sequence of choice because the high signal
from fat is suppressed, making enhancement of
abnormal tissue more conspicuous .
Advantages:
Short scan times.
excellent spatial resolution and depiction of anatomic detail
Disadvantage:
lower sensitivity for detecting soft-tissue edema
compared with fluid-sensitive sequences such as
fat-suppressed T2-weighted and STIR sequences.
T1 WEIGHTED IMAGING

82. GADOLINIUM ENHANCED T1
IMAGING

83. Advantages:
excellent for detecting edema/fl uid, which appears
bright and is often associated with pathologic processes
such as tumors, infection, fractures, tenosynovitis, and
bone contusions
good for evaluating ligaments and tendons, cartilage and
fluid-filled structures such as cysts.
Disadvantage:
Long imaging time
inability to detect marrow pathology when not
combined with fat-suppression techniques
T2 WEIGHTED IMAGING

84. are excellent for depicting anatomic detail
because of the high signal-to-noise ratio of
proton-density–weighted images.
used to evaluate regions obscured by high signal
on T2-weighted images.
Fat-suppressed proton-density imaging is often
used for the MRI evaluation of meniscal and
articular cartilage.
Disadvantage: not sensitive for the detection of
fl uid and marrow pathology.
PROTON-DENSITY SE AND
PROTON-DENSITY FSE

85. like T2-weighted sequences with fat suppression, is excellent for
detecting fluid and edema when administered with a long TE.
STIR can be used as an alternative to T2-weighted imaging.
Change the appearance of white to black; highlighting liquids.
On fluid-sensitive-images such as STIR, fluid appears bright and makes
the edema and fluid associated with certain types of pathology more
conspicuous than they are on non–fluid-sensitive sequences.
Such pathology includes osteomyelitis, fasciitis, abscesses, metastases,
primary bone tumors, fractures, tenosynovitis, tendon tears, and bone
contusions.
STIR(SHORT TAU INVERSION
RECOVERY)

86. Fat remain bright and hence difficult to differentiate it from liquid.
Hence fat suppression is required and can be performed using STIR
CAN REDUCE METAL ARTEFACT
SPIN ECHO

87. 1. determination of pulse sequence for review
2. evaluation of T2 weighted images
3. evaluation of T1 weighted images
4. evaluation of specialised pulse sequenes
5. correlation of imaging findings with clinical history and
examination findings
EVALUATION OF MRI

88. T1-weighted image
T2-weighted image
Intermediate-weighted or proton-density–weighted image
Fluid-sensitive sequence, such as STIR or fat-suppressed T2-weighted image
Gradient-echo image
Postgadolinium T1-weighted image
SEQUENCE OF MRI USED MOSTLY FOR MUSCULOSKELETAL
SYSTEM

89. On T1 image, fluid(as in joint, bladder, CSF) will appear dark.
In T2 image, fluid will appear bright/white
Recognition of the TR and TE values, which are often printed on
the film can give idea regarding image sequence.(TR value is
usually 300 to 800 ms for T1-weighted images and 2000 to 5000
ms for T2-weighted images)
HOW TO RECOGNISE T1 VS T2
IMAGE?

90. Suppression of signal from fat.
Images appear darker than conventional T2
help accentuate the increase in T2-weighted signal
(relative to the adjacent tissues)
In evaluation of bone marrow edema and edema
secondary to other pathologic processes.
FAT-SUPPRESSED T2-WEIGHTED IMAGES OR
STIR IMAGES

91. STIR

92. STIR

93. Postgadolinium T1-weighted images and fat-
suppressed postgadolinium T1-weighted images are
typically obtained for the evaluation of infection,
tumor, and postsurgical changes or scar.
fluid seems to be dark, and the pathology seems to
be bright,in postgadolinium T1-weighted image
POSTGADOLINIUM T1-WEIGHTED
IMAGES

94. POST GADOLINIUM
ENHANCEMENT

95. Trauma( hemarthrosis, meniscal tears, ACL tear, PCL tear, MCL and LCL tear,
quadeiceps and patellar tendon rupture, etc)
Degenerative conditions
Infection
Inflammatory
Tumors
Miscellaneous
MRI FINDINGS IN SOME
COMMON KNEE CONDITIONS

96. T1 VS T2 IMAGES: SAGITTAL(LATERAL TO
MEDIAL)

101. T1 VS T2 IMAGES: CORONAL(ANTERIOR TO
POSTERIOR)

106. T1 VS T2: AXIAL VIEWS(CEPHALO-
CAUDAL)

110. Traumatic
Degenerative knee conditions
Inflammatory knee conditions
Infective knee conditions
Tumors
MRI FINDINGS IN COMMON
ORTHOPEDIC KNEE CONDITIONS

111. MRI is commonly used to discern the etiology of an acute
hemarthrosis,
especially when the knee is too tender or the patient
is too anxious for a thorough physical examination.
MRI is especially helpful when conventional radiographs are
negative.
Typically, acute hemarthrosis appears as fluid within the joint with
high signal intensity on T2-weighted images
and intermediate signal intensity on T1-weighted images
HEMARTHORIS

112. BONE MARROW CONTUSIONS

113. MARROW EDEMA

114. Meniscal tears are graded according to how they appear on MRI and
are best seen on T1-weighted, gradient-echo, and proton-density
images.
Menisci show low intensity on all sequences.
uses MRI findings to categorize tears as follows
• Horizontal
• Vertical radial
• Vertical longitudinal with/without flap displacement
• Complex
MENISCAL TEARS

115. HORIZONTAL TEAR OF POST. HORN OF
MED. MENISCUS

116. GRADING OF MENISCAL TEARS

117. MENISCAL TEAR WITH CYST

123. DOUBLE PCL SIGN

124. ACL TEARS

126. CHRONIC ACL TEAR

127. PCL TEARS

128. PARTIAL PCL TEAR

129. MCL TEAR

131. PATELLAR TENDON RUPTURE

132. PATELLA ALTA

133. PATELLA BAJA

134. CHONDROMALACIAE PATALLAE

135. QUADRICEPS TENDON RUPTURE

136. LOOSE BODIES

137. MEDIAL RETINACULUM TEAR

138. SYNOVIAL CHONDROMATOSIS

139. OSTEOARTHRITIS

140. STRESS FRACTURE

141. JUMPER’S KNEE

142. OSGOOD’S SCHLATTER DISEASE

143. DISCOID MENISCUS

144. PLICAE

145. SUPRA PATELLAR PLICA

146. PES
ANSERINUS
BURSITIS

147. PRE PATELLAR BURSITIS

148. OSTEONECROSIS

149. BAKER CYST

150. CHONDRAL DELAMINATION

151. OSTEOCHONDRAL FRACTURE

152. OSTEO
CHONDRITIS
DESSICANS

153. SYNOVIAL CYST

154. CHONDROBLASTOMA

155. CHONDROBLASTOMA

156. ENCHONDROMA

157. NON OSSIFYING FIBROMA

158. CHONDROMYXOID FIBROMA

159. OSTEO
CHONDROMA

160. GIANT CELL TUMOR

161. ANEURSYMAL BONE CYST

162. OSTEOSARCOMA

163. OSTEOSARCOMA

164. SEPTIC ARTHRITIS

165. THANK YOU