I have a follow-up to the discussion I started in this earlier thread:
"Bone damage progression despite therapy response" (started Oct 22, 2015)
I did finally get a PET/CT scan to try to pinpoint the reasons for my continued, intense bone pain, in spite of achieving what is now a complete response to chemotherapy – cyclophosphamide, Kyprolis (carfilzomib), and dexamethasone.
I have not reviewed the results of the test with my oncologist yet, but have a question about the radiologist's report that I thought some who have had this test might be able to help me with.
Specifically, the test showed "mild increased FDG uptake" in the ribs (which also exhibited multiple fractures), and in the vertebrae (where I have multiple compression fractures).
The report said that the FDG uptake could be from increased osteoblastic activity in the fracture areas, or also may indicate continued myeloma activity.
My question is how to interpret this comment, since I was under the impression that a PET/CT scan definitively disclosed whether there was active myeloma in the bones. But this report seems to suggest that such active myeloma is only one possible explanation for the perceived increased FDG uptake (I am assuming that "FDG" refers to the nuclear agent one is injected with prior to the test).
If there are any PET/CT veterans out there who can shed some light on this, I would very much appreciate your input. Thanks so much.
Forums
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MrPotatohead - Name: MrPotatohead
- Who do you know with myeloma?: Me
- When were you/they diagnosed?: March, 2015
- Age at diagnosis: 65
Re: "Mild increased FDG uptake" on PET/CT - what's it mean?
PH,
The way I understand it is that when a fracture or lytic lesion is healing, new bone material is being laid down at an increased rate during the early phases of the healing process and before remodeling takes place. In this situation, you have increased osteoblastic activity (the laying down of bone) versus what you see in a normal osteoblastic / osteoclastic process (laying-down and stripping-away of bone). FDG (the radioactive, sugary koolaid compound you have before the PET/CT) uptake does in fact increase in areas of the skeleton where there is significant osteoblastic activity versus what is seen in bones with normal osteoblastic / osteoclastic activity - just as FDG uptake increases in areas where cancer cells are present (which have increased metabolic activity versus normal cells and therefore suck up more of the radioactive koolaid).
You can in fact see this situation in a before-and-after set of PET/CT images where FDG uptake persists in a fracture area of a multiple myeloma patient being treated for multiple myeloma. See Figure 5 of the article I just posted about this morning.
I would think it would be up to your doc to continue to monitor the suspect area to make sure that the FDG uptake is due to the healing process as opposed to new multiple myeloma developing.
The way I understand it is that when a fracture or lytic lesion is healing, new bone material is being laid down at an increased rate during the early phases of the healing process and before remodeling takes place. In this situation, you have increased osteoblastic activity (the laying down of bone) versus what you see in a normal osteoblastic / osteoclastic process (laying-down and stripping-away of bone). FDG (the radioactive, sugary koolaid compound you have before the PET/CT) uptake does in fact increase in areas of the skeleton where there is significant osteoblastic activity versus what is seen in bones with normal osteoblastic / osteoclastic activity - just as FDG uptake increases in areas where cancer cells are present (which have increased metabolic activity versus normal cells and therefore suck up more of the radioactive koolaid).
You can in fact see this situation in a before-and-after set of PET/CT images where FDG uptake persists in a fracture area of a multiple myeloma patient being treated for multiple myeloma. See Figure 5 of the article I just posted about this morning.
I would think it would be up to your doc to continue to monitor the suspect area to make sure that the FDG uptake is due to the healing process as opposed to new multiple myeloma developing.
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Multibilly - Name: Multibilly
- Who do you know with myeloma?: Me
- When were you/they diagnosed?: Smoldering, Nov, 2012
Re: "Mild increased FDG uptake" on PET/CT - what's it mean?
Multibilly,
Thanks very much for clarifying this. I had thought that the PET/CT scan gave a definitive indication for the presence of myeloma, but I guess that is too simplistic.
I wonder, though, what additional indications, during the recommended continued monitoring of areas showing increased FDG uptake, would point to myeloma rather than a healing process.
Thanks very much for clarifying this. I had thought that the PET/CT scan gave a definitive indication for the presence of myeloma, but I guess that is too simplistic.
I wonder, though, what additional indications, during the recommended continued monitoring of areas showing increased FDG uptake, would point to myeloma rather than a healing process.
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MrPotatohead - Name: MrPotatohead
- Who do you know with myeloma?: Me
- When were you/they diagnosed?: March, 2015
- Age at diagnosis: 65
Re: "Mild increased FDG uptake" on PET/CT - what's it mean?
PH,
I was wondering the same thing. I have no idea, short of monitoring the area over time with PET/CTs. Sounds like a great question for your specialist
I was wondering the same thing. I have no idea, short of monitoring the area over time with PET/CTs. Sounds like a great question for your specialist
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Multibilly - Name: Multibilly
- Who do you know with myeloma?: Me
- When were you/they diagnosed?: Smoldering, Nov, 2012
Re: "Mild increased FDG uptake" on PET/CT - what's it mean?
PH,
PET CTs only show where there is a lot of metabolic activity, for any reason. Even normal, healthy function. That's why the heart, kidneys, gut, and brain always show up so brightly. Once I asked if I could knit while I wait, but they told me no, because it makes the forearm muscles show a lot of uptake, and they were worried about my forearms sucking up all the sugar solution.
Other reasons for uptake: inflammation, arthritis, anything that is in the process of healing (no matter where the injury came from), and of course tumors.
So for example, my very large dog pulled me over on the leash in the fall, and I was SURE I had broken at least one rib. The breaks did not show up on x-ray. Rib fractures are notorious for being invisible on x-ray. Then I had a PET this past month for routine re-staging. Two broken ribs, in the process of healing! Darn dog! By the way, I was taking him into a training class for dogs with behavior problems like pulling on leashes. Oh, the irony.
Anyway, PETs definitely need interpretation. It's easy to figure out why there's uptake where there is a known injury (like my doggie-caused broken ribs). It's very difficult when the original injury was actually caused by myeloma, as in the case of a pathologic fracture (the medical term for a bone break caused by a disease-induced weakness in the bone, rather than trauma). Then it can be difficult to tell if the uptake is from natural healing WITHOUT any new tumor, or the presence of new tumor.
This is where the art of medicine comes in. The radiologist can usually give an opinion about whether or not the images look like typical normal healing vs. tumor. Then the oncologist has to take into account all the rest of the clinical data - things like labs results, and the patient's symptoms. See? It's an art!
By the way, there are extremely few things that give a definitive answer in medicine. Almost EVERYTHING is like this – interpretation and combination of pieces of evidence. Doctors are detectives, trying to put all these little pieces of evidence into a coherent picture.
PET CTs only show where there is a lot of metabolic activity, for any reason. Even normal, healthy function. That's why the heart, kidneys, gut, and brain always show up so brightly. Once I asked if I could knit while I wait, but they told me no, because it makes the forearm muscles show a lot of uptake, and they were worried about my forearms sucking up all the sugar solution.
Other reasons for uptake: inflammation, arthritis, anything that is in the process of healing (no matter where the injury came from), and of course tumors.
So for example, my very large dog pulled me over on the leash in the fall, and I was SURE I had broken at least one rib. The breaks did not show up on x-ray. Rib fractures are notorious for being invisible on x-ray. Then I had a PET this past month for routine re-staging. Two broken ribs, in the process of healing! Darn dog! By the way, I was taking him into a training class for dogs with behavior problems like pulling on leashes. Oh, the irony.
Anyway, PETs definitely need interpretation. It's easy to figure out why there's uptake where there is a known injury (like my doggie-caused broken ribs). It's very difficult when the original injury was actually caused by myeloma, as in the case of a pathologic fracture (the medical term for a bone break caused by a disease-induced weakness in the bone, rather than trauma). Then it can be difficult to tell if the uptake is from natural healing WITHOUT any new tumor, or the presence of new tumor.
This is where the art of medicine comes in. The radiologist can usually give an opinion about whether or not the images look like typical normal healing vs. tumor. Then the oncologist has to take into account all the rest of the clinical data - things like labs results, and the patient's symptoms. See? It's an art!
By the way, there are extremely few things that give a definitive answer in medicine. Almost EVERYTHING is like this – interpretation and combination of pieces of evidence. Doctors are detectives, trying to put all these little pieces of evidence into a coherent picture.
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Tracy J - Name: Tracy Jalbuena
- Who do you know with myeloma?: Me
- When were you/they diagnosed?: 2014
- Age at diagnosis: 42
Re: "Mild increased FDG uptake" on PET/CT - what's it mean?
Thanks, Tracy, for the detailed explanation of a PET (positron emission tomography) scan's uptake of a form of radioactive sugar. I have never had one done, but I realize that sometimes for patients with active myeloma they are used. i think that perhaps they are used more for patients who have 'nonsecretory disease', would that be correct? Or in your case, for a 're-staging' of your myeloma.
Your description of medical science as detective work is quite accurate I think.
Your description of medical science as detective work is quite accurate I think.
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Nancy Shamanna - Name: Nancy Shamanna
- Who do you know with myeloma?: Self and others too
- When were you/they diagnosed?: July 2009
Re: "Mild increased FDG uptake" on PET/CT - what's it mean?
I'm more confused than ever. I understand how FDG lights up increased metabolism, and how the increased metabolism can be from several sources.
I had a PET this month. I prepped with proper diet. They tested my glucose. They injected me with an IV. I drank a large beverage.
I assumed I was drinking glucose and the IV was radioactive. I asked, and the tech said I was NOT drinking glucose and she would show me what was mixed (I should have asked to see the mixture). She said a name that I recognized was a diet (faux) sugar. Now, I could be grossly wrong about that.
Now searching the internet it looks like
1) Indeed I was NOT drinking a glucose drink, and;
2) I was injected with a 'radioactive glucose'.
So, what is it?
Why did I drink a faux glucose solution.
I had a PET this month. I prepped with proper diet. They tested my glucose. They injected me with an IV. I drank a large beverage.
I assumed I was drinking glucose and the IV was radioactive. I asked, and the tech said I was NOT drinking glucose and she would show me what was mixed (I should have asked to see the mixture). She said a name that I recognized was a diet (faux) sugar. Now, I could be grossly wrong about that.
Now searching the internet it looks like
1) Indeed I was NOT drinking a glucose drink, and;
2) I was injected with a 'radioactive glucose'.
So, what is it?
Why did I drink a faux glucose solution.
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blueblood - Name: Craig
- Who do you know with myeloma?: Myself
- When were you/they diagnosed?: March 2014
- Age at diagnosis: 54
Re: "Mild increased FDG uptake" on PET/CT - what's it mean?
Blue blood,
I'm not sure what you drank. Typically the FDG labelled sugar is given via IV, and that's the only kind I've ever had. I've never had to drink anything for a PET.
There is another kind of labeling for a PET that is supposed to be a little different sensitivity for bone lesions. NaF is an alternate or additional label. It is supposed to be a little better at finding metastatic bone lesions. However, I remember (somewhere) a myeloma expert telling me that it is not preferred in myeloma in particular because it doesn't necessarily give better results. Also, it's important to be able to compare one PET CT to the next, so there is tremendous value in consistency.
I'm not sure how NaF is administered. Maybe it's an oral solution!
Here's a Beacon forum about FDG vs NaF:
"F-18 FDG PET vs F-18 sodium fluoride (F-NaF) PET" (started Apr 5, 2015)
Tracy
I'm not sure what you drank. Typically the FDG labelled sugar is given via IV, and that's the only kind I've ever had. I've never had to drink anything for a PET.
There is another kind of labeling for a PET that is supposed to be a little different sensitivity for bone lesions. NaF is an alternate or additional label. It is supposed to be a little better at finding metastatic bone lesions. However, I remember (somewhere) a myeloma expert telling me that it is not preferred in myeloma in particular because it doesn't necessarily give better results. Also, it's important to be able to compare one PET CT to the next, so there is tremendous value in consistency.
I'm not sure how NaF is administered. Maybe it's an oral solution!
Here's a Beacon forum about FDG vs NaF:
"F-18 FDG PET vs F-18 sodium fluoride (F-NaF) PET" (started Apr 5, 2015)
Tracy
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Tracy J - Name: Tracy Jalbuena
- Who do you know with myeloma?: Me
- When were you/they diagnosed?: 2014
- Age at diagnosis: 42
Re: "Mild increased FDG uptake" on PET/CT - what's it mean?
The first time I had a PET/CT about 3 1/2 years ago, I had to drink a barium sulfate contrast "milkshake" (they offered me different flavors) and then was later injected with FDG via a formidable looking radioactive shielded syringe like this one:
But the last time I had a PET/CT, the tech said they had done away with the barium sulfate milkshakes and only did the FDG injection.
- PETSyringeShield.jpg (26.04 KiB) Viewed 13317 times
But the last time I had a PET/CT, the tech said they had done away with the barium sulfate milkshakes and only did the FDG injection.
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Multibilly - Name: Multibilly
- Who do you know with myeloma?: Me
- When were you/they diagnosed?: Smoldering, Nov, 2012
Re: "Mild increased FDG uptake" on PET/CT - what's it mean?
Thanks all,
For clarification (or, as a boss would say, "for clearification"), I meant I had PET/CT's, not PET's. The schedules always say PET, but the reports say PET/CT.
When in doubt - read the directions. I looked up my results and I found this:
RADIOPHARMACEUTICAL:
11.46 mCi F-18 FDG administered in the left antecubital fossa intravenously.
and:
Oral contrast was given.
There it was the whole time, maybe the faux sugar was to make the contrast more palatable. I knew the real juice was in the syringe Multibilly referenced. They always respect it. I've had 10 PET/CT's in two years.
For clarification (or, as a boss would say, "for clearification"), I meant I had PET/CT's, not PET's. The schedules always say PET, but the reports say PET/CT.
When in doubt - read the directions. I looked up my results and I found this:
RADIOPHARMACEUTICAL:
11.46 mCi F-18 FDG administered in the left antecubital fossa intravenously.
and:
Oral contrast was given.
There it was the whole time, maybe the faux sugar was to make the contrast more palatable. I knew the real juice was in the syringe Multibilly referenced. They always respect it. I've had 10 PET/CT's in two years.
-
blueblood - Name: Craig
- Who do you know with myeloma?: Myself
- When were you/they diagnosed?: March 2014
- Age at diagnosis: 54
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