Replies to post #230029 on NorthWest Biotherapeutics Inc (NWBO)

[beartrap12]

Survivor, thanks for this paper by Dr. Liau and company. It seems like they’ve found a way to separate progression in GBM from pseudo progression. But maybe others can weigh in. It says:

In conclusion, by combining dCK-based PET and MRI modalities, we are able to noninvasively localize and quantify immune responses induced by immunotherapy. The percentage of tumor volume containing an activated lymphocytic infiltrate is positively correlated with survival in animals. ITRI not only allows us to quantify the immune response in CNS tumors using noninvasive means, but also serves to standardize how we quantify this immunity, to potentially serve as a predictive biomarker of survival and antitumor immune response in a reproducible fashion among patient populations. Additional studies in patients are needed to explore the clinical significance of the changes observed with these imaging modalities.

[radonculous]

I printed this paper and I'm going to take a look at it this weekend. I'll let you know what I think.

In general, there are some interesting ways to determine the composition of a tissue on an MRI with some of these techniques.

MRI Spectroscopy has some metabolites that can be used:

NAA - marker for neuronal viability, found in high concentrations in neurons, and reduced by any process that destroys neurons

Creatine - found in metabolically active tissue, reduced in gliomas

Choline - marker of cellular membrane turnover, elevated in neoplasms, demyelination, and gliosis. In Gliomas, elevation of choline beyond margins of contrast demonstrate cellular infiltration of tumor

Lactate - marker of anaerobic metabolism and is therefore elevated in necrotic areas, higher grade tumors

A recurrence on an MRI Spectroscopy would show: increased choline, decreased creatine, and the Choline/NAA ratio would be >2.

Radiation necrosis would have increased lactate and decreased choline, creatine, and NAA

Perfusion weighted MRIs can be helpful too. It can estimate the microvascular density (MVD) by measuring the cerebral blood volume. Radiation therapy leads to endothelial cell damage and small vessel injury, so there is reduced perfusion and reduced MVD. Tumor recurrence promotes angiogenesis (making new blood vessels) and thus increases MVD