What is articular cartilage..?

A highly specialized connective tissue in joints.

Provides smooth lubrication and load transmission .

Limited capacity for healing and repair

Normal cartilage on arthroscopy

Why MR imaging of cartilage…?

MRI directly assesses cartilage.

Reliable assessment of cartilage loss and volume.

Assessment of cartilage matrix composition.

How do MRI and plain radiographs compare ..?

Plain radiographs are insensitive to early cartilage loss and focal cartilage defects.

Widely available does not require much expertise.

Sensitive to cartilage loss and defects.

Not widely available and requires expert technique.

How does normal cartilage look On MRI.?

Cartilage is best assessed in fat suppressed sequences .

When I read through cartilage imaging , so many terms I encounter , what are they..? 2D imaging. 3D imaging. DESS SPACE. T2 mapping deGMRIC technique Sodium MRI

Composition of cartilage

Size and cartilage signal

What is T2 mapping..?

A technique to assess quality of cartilage , red color denoting increased degeneration of cartilage.

MRI versus arthroscopy in cartilage assessment.

MRI can not replace arthroscopy . MRI techniques showed a sensitivity of 38 %

and specificity of 98%. Newer cartilage specific techniques are

expected to improve sensitivity.

Cases

Case 1 20 year old lady with knee pain , mainly

complains of pain anteriorly. Normal plain radiographs.

Diagnosis..

Chondromalacia patella.

How do you grade chondromalacia patella on MRI..?

Grade 1– focal hyperintensity.Arthroscopically corresponds to swelling or softening

Grade 2- blister or fraying of articular cartilage.Arthroscoplically – fissuring of articular cartilage

Grading of chondromalacia..contd

Grade 3- partial thickness cartilage lossArthroscopy– crabmeat appearance.

Grade 4- full thickness cartilage loss with bone reactive changes.Arthroscopy– destroyed cartilage with exposed bone.

Case 2

20 years old male complains of knee pain and swelling.

Osteochondral fragment in osteochondritis dissecans. MRI can assess stability of fragment and overlying cartilage.

How does cartilage loss look on MRI…?

Case 4

20 year old female with knee pain.

Slide taken from radiographics journal Jan-Feb 2011

Large osteochondral fragment medial femoral condyle

Slide taken from radiographics journal Jan-Feb 2011

Follow up MRI 18 months after autologous chondrocyte implantation.

It shows heterogenous tissue at site of surgery

Cartilage MRI shows normal layering of cartilage absent at operated site.

Slide taken from radiographics journal Jan-Feb 2011

In short , what I want to say.. MRI is an exciting tool for cartilage assessment. One can assess volume of cartilage , quality of

cartilage , focal defects on MRI today At present arthroscopy remains gold standard

for cartilage evaluation , MRI is not yet sensitive enough.