MRI of Knee

Question 1

essential MRI sequence for examining the menisci

Answer 1

sag T1 or PD

Question 2

knee should be in what position during MRI

Answer 2

externally rotated about 5 to 10 degrees

Question 3

3 MRI sequences to examine cruciate ligaments and cartilage

Answer 3

FSE, T2 or T2* GRASS

Question 4

used to examine the collateral ligaments and cartilage and look for meniscocapsular separations

Answer 4

coronal images

Question 5

used for viewing the patellofemoral cartilage, identifuing bursal fluid collections and for a second look at the cruciate and collateral ligaments

Answer 5

axial images

Question 6

a fibrocartilaginous, C-shaped structure that is uniformly low in signal on both T1 and T2 weighted images

Answer 6

menisci

Question 7

meniscal signal that does not disrupt an articular surface is representative of

Answer 7

instrasubstance degeneration

Question 8

high signal in meniscus disrupts the superior or inferior articular surface

Answer 8

meniscal tear

Question 9

most common type of meniscal tear

Answer 9

oblique horizontal tear extending to the inferior surface of the posterior horn of the medial meniscus

Question 10

type of meniscal tear that occurs along a plane perpendicular to the long axis of the meniscus and involves at least tje inner free edge portion of the meniscus; if large, a radial tear may extend across the full width of the meniscus

Answer 10

parrot beak or radial tear

Question 11

ACL tears usually happens at the

Answer 11

periphery of the menisci

Question 12

lateral meniscus tears happen at what portion of the menisci

Answer 12

posterior horn

Question 13

longitudinally-oriented tear of the mensicus resulting in inner free edge of the meniscus becoming displaced towards the intercondylar notch

Answer 13

Bucket-handle tear

Question 14

only one image is present that has the bow-tie appearance of the body segment of the meniscus

Answer 14

Bucket-handle tear

Question 15

normal size of meniscus

Answer 15

9 to 12 mm wide and 4- 5 mm thickness

Question 16

large meniscus that can have many different shapes; lens-shaped, wedged, flat

Answer 16

discoid meniscus

Question 17

discoid meniscus is commonly seen in what meniscus

Answer 17

lateral meniscus

Question 18

lateral meniscus often has what appears to be a tear on the anterior horn near its upper margin, which is a ______ from the insertion of the transverse ligament

Answer 18

pseudotear

Question 19

seen in the intercondylar notch as a linear, predominantlly low signal structure on T1. often shows some linear striations onto the medial tibial spine when viewed on sagittal images

Answer 19

ACL

Question 20

when ACL is torn, it appears

Answer 20

it is not visualized

Question 21

partial tears or sprains of the ACL are manifested by

Answer 21

high signal and/or laxity within an otherwise intact ligament

Question 22

gently curved, homogeneously low-signal structure that is infrequently torn or even less frequently repaired by surgeons. when torn, it appears thickened and it has diffuse intermediate signal throughout

Answer 22

posterior cruciate ligament

Question 23

normal size of PCL

Answer 23

6 mm or less in diameter

Question 24

when PCL is torn, it has a thickness of

Answer 24

7mm or thicker

Question 25

low-signal, round structure often seen just anterior or poterior to the PCL, as seen in sagittal views. a loose body or displaced fragment of a piece of torn meniscus can have this appearance

Answer 25

meniscofemoral ligament

Question 26

a meniscofemoral ligament passes infront of PCL, it is called _____; if it passes behind the PCL, it is called _____

Answer 26

ligament of Humphrey (anterior), ligament of Wrisberg (posterior)

Question 27

originates in the medial femoral condyle and inserts on the tibia. it is closely applied to the joint and is intimately associated with the medial joint capsule and medial meniscus

Answer 27

MCL

Question 28

injuries to MCL usually occur from

Answer 28

valgus stress to the lateral part of the knee (such as clipping injury in football)

Question 29

grade of MCL injury: mild sprain and is diagnosed on MR by the presence of fluid or hemorrhage in the soft tisue medial to the MCL. ligament is otherwise normal

Answer 29

grade 1

Question 30

grade of MCL injury: partial tear and is seen as high signal in and around the MCL on T2 and T2* coronal sequences. ligament is intact, altho the deep or superficial fibers may show minimal disruption

Answer 30

grade 2

Question 31

grade of MCL injury: complete disruption of MCL

Answer 31

grade 3

Question 32

speckled appearance of anterior horn of lateral menscus, normal or abnormal

Answer 32

normal variant

Question 33

occurs when the medial meniscus is torn from its attachment to the joint capsule. this occurs most commonly at the site of MCL and often occurs concomitantly with an MCL injury

Answer 33

meniscocapsular separation

Question 34

this ligament consist of 3 parts; most posterior is the tendon of biceps femoris, which inserts onto the head of fibula. next, anterior to the biceps, which extends from the lateral femoral condyle to the head of fibula

Answer 34

LCL

Question 35

anterior to the fibullar collateral ligament is the _____, which extends into the fascia more anteriorly and inserts onto Gerdy tubercle on the tibia

Answer 35

iliotibial band

Question 36

patellar cartilage commonly undergoes degeneration, cuasing exquisite pain and tenderness. this is called

Answer 36

chondromalacia patella

Question 37

a frequent cause of a patellar cartilage defect is

Answer 37

dislocation of patella

Question 38

normal structure seen in over half of the population, which is an embryologic remnant from when the knee was divided into three compartments. it is a thin fibrous band that extends from the medial capsule towards the medial facet of the patella

Answer 38

patellar plica

Question 39

when a patellar plica cause clinical symptoms that are indistinguishable from those of a torn meniscus, it is termed

Answer 39

plica syndrome

Question 40

represents microfractures from trauma. they are easily identified on T1W images as subarticular areas of inhomogeneous low signal. in T2, it demonstraes increased signal for several weeks depending on its severity

Answer 40

bone contusions

Question 41

bone contusions can progress to _____ if they are not treated with decreased weight bearing

Answer 41

osteochondritis dissecans

Question 42

a commonly seen bone contusion is one that occurs on the posterior part of the lateral tibial plateau with an associated “kissing” contusion in the central to anterior lateral femoral condyle. this has been called

Answer 42

“pivot-shift” contusion pattern

Question 43

a fracture that is almost always associated with an internal derangement is the _____. A small, bony fragment pulled off the lateral tibial joint line by an avulsion of the lateral joint capsule, it is almost always associated with an ACL tear

Answer 43

Segond fracture

Question 44

an abnormality that can cause joint pain and clinically mimic plica syndrome or a torn meniscus is

Answer 44

bursitis

Question 45

an uncommon medial bursa; three tendons– the sartorius, gracilis and semitendinosus—insert onto the anterior medial aspect of the tibia in a fan-shaped manner that has been likened to a Goose’s foot. the bursa lies beneath the insertion site, which can be inflamed and cause medial joint line or patellar pain and can be confused clinically with a torn medial meniscus

Answer 45

pes anserine bursa

Question 46

much more common medial bursa that occurs at the medial joint line and often mimics a meniscal cyst. it has a characteristic comma shape as it drapes over the semimembranosus tendon

Answer 46

semimembranosus tibial collateral ligament bursa