0:00

<v ->But in general, the diagnosis with imaging

0:03

in cases of osteonecrosis and bone infarcts is easy,

0:09

but not in the early stages.

0:11

In the early stages, there may be nonspecific,

0:14

feathery or nodular appearance of altered marrow signal.

0:19

And it's only later on, as things get more organized,

0:23

that you see the serpentine-like arrangement

0:26

of the border and areas of fat within the site of necrosis.

0:33

In addition, with regard to differential diagnosis,

0:36

fat necrosis, different from trabecular necrosis,

0:41

certainly can involve the skeleton.

0:44

We see this on an idiopathic basis

0:47

but it has an association with variety of conditions.

0:52

I would emphasize the association of fat necrosis

0:56

with pancreatic disease.

0:58

It may be acute or chronic pancreatitis.

1:01

In this case, acute pancreatitis.

1:04

It may be a manifestation of a pancreatic carcinoma,

1:08

and in the child, child abuse with traumatic pancreatitis

1:13

can also lead to areas of fat necrosis.

1:17

And one of the other interesting conditions

1:20

that can simulate osteonecrosis I became aware of,

1:24

because one of our previous visiting scholars from Taiwan

1:28

sent me a case and then reported a series of these

1:32

in the radiology literature.

1:34

And these areas relate to

1:36

laser radiofrequency heated probes.

1:39

We're looking at thermal necrosis.

1:41

And this had occurred at several spas in Taiwan,

1:45

where they were indeed using these heated probes.

1:50

What was very characteristic about these

1:53

is the peripheral location of these areas.

1:57

So the probes are being used on the skin.

2:01

So you would expect in fact that you would get necrosis

2:05

that would be superficially located.

2:07

And that is the clue to the accurate diagnosis

2:11

of this condition.

2:13

With regard to the classification,

2:17

there are many systems of classification,

2:20

the initial ones based mainly on conventional radiography,

2:24

the more recent ones based on MR imaging.

2:28

I'm not gonna go through those today,

2:30

but the Ficat and Arlet classification

2:33

is very popular when talking about conventional radiography.