TY  - PCOMM
AU  - Galldiks, Norbert
AU  - Werner, Jan-Michael
AU  - Stoffels, Gabriele
AU  - Kocher, Martin
AU  - Tscherpel, Caroline
AU  - Jain, Rajan
AU  - Shah, Nadim
AU  - Fink, Gereon
AU  - Langen, Karl-Josef
AU  - Lohmann, Philipp
TI  - NIMG-05. THE T2-FLAIR MISMATCH SIGN IN IDH-MUTANT ASTROCYTOMAS - IS THERE AN ASSOCIATION WITH FET PET UPTAKE?
M1  - FZJ-2022-02465
PY  - 2019
AB  - BACKGROUNDThe purpose of this study was (i) to assess the reproducibility of the previously described T2-FLAIR mismatch sign as a highly specific MR imaging marker in non-enhancing IDH-mutant, 1p/19q non-codeleted lower-grade gliomas (LGG) of the WHO grades II or III, and (ii) its association with the uptake of the radiolabeled amino acid O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) in PET to further metabolically characterize that sign, which is currently poorly understood.METHODSConsecutive MRI and dynamic FET PET scans (n=134) from newly diagnosed and neuropathologically confirmed IDH-mutant LGG (n=65) and IDH-wildtype gliomas as control group (n=69) were evaluated by two independent raters to assess presence/absence of the T2-FLAIR mismatch sign as well as FET uptake. Interrater agreement was assessed using Cohen’s kappa (κ), as well as diagnostic performance (i.e., positive/negative predictive value; PPV, NPV) of the T2-FLAIR mismatch sign to identify IDH-mutant astrocytomas.RESULTSIn the LGG group, 13 patients (20%) had a T2-FLAIR mismatch sign, which could be identified with a substantial interrater agreement (κ=0.75). In contrast, that sign was absent in IDH-wildtype gliomas. All 13 cases that were positive for the T2/FLAIR mismatch sign were IDH-mutant, 1p/19q non-codeleted tumors (PPV=100%, NPV=57%). Interestingly, compared to IDH-mutant gliomas without the T2-FLAIR mismatch sign, the sign was significantly (P=0.027; 10 of 13 patients) associated with a negative FET PET scan (i.e., 5 tumors with indifferent FET uptake comparable to the background activity, or FET uptake below background activity (photopenic defect) in 5 tumors).CONCLUSIONSWith a robust interrater agreement, our findings are in line with previously reported findings regarding the T2-FLAIR mismatch sign. Additionally, the T2-FLAIR mismatch sign seems to be significantly related with a lack of increased FET uptake in PET, which may help to further characterize patients with that sign. Notwithstanding, the clinical relevance of this imaging constellation warrants further investigation.
LB  - PUB:(DE-HGF)4
UR  - https://juser.fz-juelich.de/record/908214
ER  -