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In this video we are going to review the follow-up PET CT

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for the patient we discussed earlier who had a

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extensive extra novel and novel lymphoma.

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On the bottom, I'm showing you the baseline PET ct.

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The second row shows the interim pit

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and the third row on top shows the end of treatment pit.

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And just comparing the MIP of these three timelines,

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you can see the progression of response.

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He had a positive response, but let's go through the pets.

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So remember, this patient had a large anterior medicinal

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noal mass and uh,

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after initiation of the treatment, the mass shrunk

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and the degree of, uh, intense uptake

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became equal to blood pool.

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So one of the things that we do in lymphoma

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is apply the devil score

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and this devil score is a visual grade scale

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and we compare the degree of uptake in the different areas

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of disease relative to blood pool and liver.

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But the one thing to know is where

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to look at the blood pool.

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This is a common question

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that I get from the residents and fellows.

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In what area did you judge blood pool?

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So by convention, the areas where

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you can find normal blood pool would be the aortic arch.

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For instance here where you have um, a large area of

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blood rather than in, in a smaller vessel.

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If not, and depending on the size,

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I would do other areas of the heart.

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But this is sometimes limited like in this case

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where you have a lot of left ventricular uptake and, and

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therefore that can be confounding.

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So I would do ascending aorta

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or aortic arch in the liver.

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Uh, since it's visual, as long

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as there is no disease in the liver, uh, would be easier

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to pick an area of representative parenchyma.

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All right, so in this case,

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overall there is improved of disease.

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All these areas of nodal disease in the neck have improved.

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For instance, as you can see,

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all these lymph nodes are smaller and no longer FDG avid.

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As we mentioned, the anterior nodal mass has also decreased

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in size and is no longer at the GI AVID

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as it has the same uptake as blood pool.

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Same goes for the upper abdominal lymph nodes,

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retroperitoneal lymph nodes,

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and the pelvic lymph nodes as well as inguinal region.

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I don't identify novel disease that

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Is still active that has

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FDG optic greater than blood pool or liver.

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What we see in this case is that there is diffuse

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uptake in the bone marrow

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and this is likely related to

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the therapy, as in these cases patients get

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bone marrow stimulator medications, uh, within

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the therapy regimen.

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And so that is demonstrated

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as a diffusely increased trace ap.

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The challenge for us is that we know

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that there was OSCEs disease

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and so this has to be mentioned in the report

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and it should be stated that it's a limitation.

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So the next follow up would be ideal if there is sufficient

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time between these bone marrow simulating factors

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and the pet.

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So this was the entering pit.

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Now let's move on to the final pit.

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And when we look at the MIP, we can see that

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there is bone marrow uptake in the axial appendicular

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skeleton, but it's not so much as it was on the entering pit

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and is definitely diffuse, not patchy

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as it was at baseline.

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Can we identify areas

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of active disease on the final PET ct?

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As we scroll through

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and we look at the pit, there were no areas

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of tracer uptake that no mask continues to be stable

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or slightly smaller in size

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and has uptake that is equal to blood pool.

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This patient had a complete response.

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Now the splenic uptake is equal to the liver and

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therefore is considered normal.

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Those areas of bulky lymph nodes in the pelvis

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and inguinal have now completely resolved.

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If you look at the size on the prior, were still measurable

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up to one centimeter in some cases

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and now they are sub centimeter all of them.

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So what do will score would we apply

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in the pet?

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I would say that

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since there was still measurable disease,

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but it was not metabolically active,

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this interim pet would have been a double two

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on the current study stays as they will too

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because there are areas of treated novel tissue

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but is not metabolically active like the anterior

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mediastinal novel mass.

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So the final impression for this patient

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after the completion of treatment would be at level two,

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which clinically corresponds

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with a complete metabolic response.