mri of knee joint-- hossam massoud
TRANSCRIPT
MRI OF THE KNEE JOINT
Hossam MassoudNational cancer institute
Cairo university inspired from
Prof. Mamdouh Mahfouz Prof. of Radiodiagnosis
Cairo University
Knee joint complaint· Pain · Trauma· Swelling · Osteoarthritis
Suspected pathology [previous Examination] · Inflammation· Tumors
MRI OF THE KNEE JOINTINDICATIONS
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
How to know the pulse sequence?!
T1/ PD T2 Gradient
STIR
PDT1 T2
PD
Structure or lesions
T2 T1
Cortical boneMenisci (medial ,lateral)Ligaments (ACL,PCL,…)Calcification
Low
Low
Common MR appearances
Common MR appearances
Fat (subcutaneous, lipoma,…)Bone marrow
Low High
Fluid (effusion, cyst, ganglion)
High
Low
Blood (heamoarthrosis)
High
High
T1 T2
Kinematic MRI
Where?! Items to be evaluated
Sagittal PD
Sagittal PDCoronalAxialSagittal PDSagittal T1& T2Sagittal T2
Menisci (medial & lateral) Ligaments - Cruciate (ACL, PCL) - Collateral - Retinacular Tendons ( Quadriceps,Pattelar) Bones Synovial effusion
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
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
AC B
A B C
Lateral meniscus
Medial meniscus
Medial & lateral menisci
Cruciate ligaments
Patellar retinacular ligaments
Meniscus:
Meniscus:
Meniscal Lesions
Tear Degeneration Cyst Discoid
Simple Tear Complex Tear
Types of Meniscal degeneration
Grade I Grade II Meniscal fraying
Tear
Tear
Meniscal degeneration with free edge fraying
Meniscal degeneration with free edge fraying
Types of Meniscal Tears
Simple Complex Special types
Simple Meniscal Tears
Horizontal Vertical Radial
Horizontal tear
Horizontal tear
Horizontal tear
Horizontal tear
Horizontal tear
Vertical tear
Occurs typically in the outer 1/3 of the posterior horn or body of the meniscus
[rare in the anterior horn]
Vertical tear
Vertical tear
Radial tear
Vertical tear of the free edge of the meniscus [ Root tear ]
Ghost meniscus
Ghost meniscus
If there is no history of Meniscal surgery and the posterior horn is absent near the intercondylar notch
Special Meniscal Tears
Flap Bucket handle MC separation
Flap tear [Oblique ]Should have tow components , horizontal and vertical
Common in the medial meniscus
Fish mouth
Decreased height , Free piece Small sized posterior horn Medially displaced fragment Double post. Cruciate ligament sign
Bucket Handel tear
Bucket Handel tear
Small sized posterior horn [ sagittal ] Medially displaced fragment[ coronal]
Double PCL sign [ sagittal ]
Bucket Handel tear
Flipped meniscus : Double Delta Sign
Bucket Handel tear , Lateral meniscus
Flipped meniscus : Double Delta Sign
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
Discoid meniscus
Discoid meniscus
Meniscal cystA Cyst extending from a meniscal tearCommon sites : Anterior horn LM , Posterior horn MM
Ligamentous Lesions
ACL PCL Collateral Retinacular
Anterior cruciate ligament
Anterior cruciate ligament
Primary signs [ In the ligament ] Total discontinuity Abnormal signal Abnormal configuration
Abrupt angulation Wavy appearance
Abnormal axis
Anterior cruciate ligament injury
Inter
cond
ylar r
oof
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 ".
*
Anterior tibial translocation
Anterior tibial translocation with” uncovered meniscus sign”
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
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%.
?
Intraligamentous ganglion cyst
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
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%
NORMAL PCL
TORN PCL
MR FINDINGS Increased signal due to
hemorrhage and edema Diffuse enlargement of PCL
COMPLETE PCL TEAR
NORMAL PCLAVULSION TEAR
• Involves the tibial insertion• Retracted bone fragment• Bone marrow edema at avulsion site• The actual PCL may be normal
AVULSION PCL TEAR
Collateral ligaments
MCL is about 8-11 cm LCL is about 5-7 cm Isolated injuries are rare,
usually with ACL and MM
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
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
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.
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
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.
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).
Acute grade III tear with a folded ligament (arrow) and surrounding edema on a coronal proton density image.
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.
?Grade III MCL tear
with retraction
?Grade III MCL tear
with abnormal signal and
edema
Lateral pressure syndrome
Thickening of the lateral retinaculum
Lateral knee pain Obese, athletic patients May be associated with
chondromalacia
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
Patella Baja
Poliomyelitis Achondroplasia JRA
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
PIGMENTED VELLONODULAR SYNOVITIS
PIGMENTED VILLONODULAR SYNOVITIS
PIGMENTED VILLONODULAR SYNOVITIS VERSUS LIPOMA ARBORESCENS
Pigmented villo-nodular synovitis
POPLITEAL CYST
Fluid in the bursa which is usually communicating with the joint spaceOther namesBaker’s cystGastrocnemius/semimembranosus bursa
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]
PLICA SYNDROME
Knee pain with Normal MRI ?!
Kinematic Meniscal contusion Plicae
Plicae
Anterior knee pain, clicking, locking Supra patellar, medial patellar,
infrapatellar Medial patellar Plicae (Normal variant)
60% of adult knee
Medial patellar Plicae
Supra patellar plica
Medial plica Syndrome
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
Osteochondritis Dissecans
OSTEOCHONDRITIS DISSECANS
OSTEOCHONDRITIS DISSECANS
Bone marrow contusion
Migratory osteoporosis
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
BONE INFARCTS
BONE INFARCTS
BONE INFARCTS
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ACL TEAR
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Synovial chondromatosis
Chondromyxoid fibroma