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RT Journal Article
SR Electronic
T1 Quantification of T2-FLAIR Mismatch in Nonenhancing Diffuse Gliomas Using Digital Subtraction
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP 188
OP 197
DO 10.3174/ajnr.A8094
VO 45
IS 2
A1 Cho, Nicholas S.
A1 Sanvito, Francesco
A1 Le, Viên Lam
A1 Oshima, Sonoko
A1 Teraishi, Ashley
A1 Yao, Jingwen
A1 Telesca, Donatello
A1 Raymond, Catalina
A1 Pope, Whitney B.
A1 Nghiemphu, Phioanh L.
A1 Lai, Albert
A1 Cloughesy, Timothy F.
A1 Salamon, Noriko
A1 Ellingson, Benjamin M.
YR 2024
UL http://www.ajnr.org/content/45/2/188.abstract
AB BACKGROUND AND PURPOSE: The T2-FLAIR mismatch sign on MR imaging is a highly specific imaging biomarker of isocitrate dehydrogenase (IDH)-mutant astrocytomas, which lack 1p/19q codeletion. However, most studies using the T2-FLAIR mismatch sign have used visual assessment. This study quantified the degree of T2-FLAIR mismatch using digital subtraction of fluid-nulled T2-weighted FLAIR images from non-fluid-nulled T2-weighted images in human nonenhancing diffuse gliomas and then used this information to assess improvements in diagnostic performance and investigate subregion characteristics within these lesions.MATERIALS AND METHODS: Two cohorts of treatment-naïve, nonenhancing gliomas with known IDH and 1p/19q status were studied (n = 71 from The Cancer Imaging Archive (TCIA) and n = 34 in the institutional cohort). 3D volumes of interest corresponding to the tumor were segmented, and digital subtraction maps of T2-weighted MR imaging minus T2-weighted FLAIR MR imaging were used to partition each volume of interest into a T2-FLAIR mismatched subregion (T2-FLAIR mismatch, corresponding to voxels with positive values on the subtraction maps) and nonmismatched subregion (T2-FLAIR nonmismatch corresponding to voxels with negative values on the subtraction maps). Tumor subregion volumes, percentage of T2-FLAIR mismatch volume, and T2-FLAIR nonmismatch subregion thickness were calculated, and 2 radiologists assessed the T2-FLAIR mismatch sign with and without the aid of T2-FLAIR subtraction maps.RESULTS: Thresholds of ≥42% T2-FLAIR mismatch volume classified IDH-mutant astrocytoma with a specificity/sensitivity of 100%/19.6% (TCIA) and 100%/31.6% (institutional); ≥25% T2-FLAIR mismatch volume showed 92.0%/32.6% and 100%/63.2% specificity/sensitivity, and ≥15% T2-FLAIR mismatch volume showed 88.0%/39.1% and 93.3%/79.0% specificity/sensitivity. In IDH-mutant astrocytomas with ≥15% T2-FLAIR mismatch volume, T2-FLAIR nonmismatch subregion thickness was negatively correlated with the percentage T2-FLAIR mismatch volume (P &lt; .0001) across both cohorts. The percentage T2-FLAIR mismatch volume was higher in grades 3–4 compared with grade 2 IDH-mutant astrocytomas (P &lt; .05), and ≥15% T2-FLAIR mismatch volume IDH-mutant astrocytomas were significantly larger than &lt;15% T2-FLAIR mismatch volume IDH-mutant astrocytoma (P &lt; .05) across both cohorts. When evaluated by 2 radiologists, the additional use of T2-FLAIR subtraction maps did not show a significant difference in interreader agreement, sensitivity, or specificity compared with a separate evaluation of T2-FLAIR and T2-weighted MR imaging alone.CONCLUSIONS: T2-FLAIR digital subtraction maps may be a useful, automated tool to obtain objective segmentations of tumor subregions based on quantitative thresholds for classifying IDH-mutant astrocytomas using the percentage T2 FLAIR mismatch volume with 100% specificity and exploring T2-FLAIR mismatch/T2-FLAIR nonmismatch subregion characteristics. Conversely, the addition of T2-FLAIR subtraction maps did not enhance the sensitivity or specificity of the visual T2-FLAIR mismatch sign assessment by experienced radiologists.AUCarea under curveIDHmisocitrate dehydrogenase mutantIDHm-Aisocitrate dehydrogenase mutant astrocytomaIDHm-Oisocitrate dehydrogenase mutant oligodendrogliomaIDHwtisocitrate dehydrogenase wild-typeNAWMnormal-appearing white matterROCreceiver operating characteristicTCIAThe Cancer Imaging ArchiveT2FMT2-FLAIR mismatchT2FNMT2-FLAIR nonmismatchVOIvolume of interest