Abstract
Few studies have shown MR imaging features and ADC correlating with molecular markers and survival in patients with glioma. Our purpose was to correlate MR imaging features and ADC with molecular subtyping and survival in adult diffuse gliomas. Presurgical MRIs and ADC maps of 131 patients with diffuse gliomas and available molecular and survival data from The Cancer Genome Atlas were reviewed. MR imaging features, ADC (obtained by ROIs within the lowest ADC area), and mean relative ADC values were evaluated to predict isocitrate dehydrogenase (IDH) mutation, 1p/19q codeletion status, MGMT promoter methylation, and overall survival. IDH wild-type gliomas tended to exhibit enhancement, necrosis, and edema; >50% enhancing area (P < .001); absence of a cystic area (P = .013); and lower mean relative ADC (median, 1.1 versus 1.6; P < .001) than IDH-mutant gliomas. By means of a cutoff value of 1.08 for mean relative ADC, IDH-mutant and IDH wild-type gliomas with lower mean relative ADC (<1.08) had poorer survival than those with higher mean relative ADC (median survival time, 24.2 months; 95% CI, 0.0-54.9 months versus 62.0 months; P = .003; and median survival time, 10.4 months; 95% CI, 4.4-16.4 months versus 17.7 months; 95% CI, 11.6-23.7 months; P = .041, respectively), regardless of World Health Organization grade. Median survival of those with IDH-mutant glioma with low mean relative ADC was not significantly different from that in those with IDH wild-type glioma. Other MR imaging features were not statistically significant predictors of survival. IDH wild-type glioma showed lower ADC values, which also correlated with poor survival in both IDH-mutant and IDH wild-type gliomas, irrespective of histologic grade. A subgroup with IDH-mutant gliomas with lower ADC had dismal survival similar to that of those with IDH wild-type gliomas.
Highlights
BACKGROUND AND PURPOSEFew studies have shown MR imaging features and ADC correlating with molecular markers and survival in patients with glioma
We showed that the “T2-FLAIR mismatch sign,” detectable using conventional MR imaging, is a highly specific imaging biomarker for the isocitrate dehydrogenase (IDH)-mutant, 1p/19q noncodeleted molecular subtype in lower grade gliomas.[7]
MR spectroscopy could detect 2-hydroxyglutarate, a metabolite that accumulates in IDH-mutant gliomas but did not discover a survival difference.[9]
Summary
Presurgical MRIs and ADC maps of 131 patients with diffuse gliomas and available molecular and survival data from The Cancer Genome Atlas were reviewed. MR imaging features, ADC (obtained by ROIs within the lowest ADC area), and mean relative ADC values were evaluated to predict isocitrate dehydrogenase (IDH) mutation, 1p/19q codeletion status, MGMT promoter methylation, and overall survival. This was a retrospective study using data from the publicly available National Institutes of Health/National Cancer Institute– approved databases of The Cancer Genome Atlas (TCGA; https://cancergenome.nih.gov) and The Cancer Imaging Archive (http://www.cancerimagingarchive.net/),[16,17,18] from which all 461 cases with imaging data were reviewed, and only cases of treatmentnaıve diffuse gliomas (WHO grades II–IV) with available DWI and ADC maps were included. We investigated the relationship among 9 different MR imaging features and 3 molecular markers (IDH mutation, 1p/19q codeletion, and MGMT promoter methylation) as well as WHO grade and overall survival
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