TY - JOUR
T1 - An analysis of image texture, tumor location, and MGMT promoter methylation in glioblastoma using magnetic resonance imaging
AU - Drabycz, Sylvia
AU - Roldán, Gloria
AU - de Robles, Paula
AU - Adler, Daniel
AU - McIntyre, John B.
AU - Magliocco, Anthony M.
AU - Cairncross, J. Gregory
AU - Mitchell, J. Ross
N1 - Funding Information:
Grant support: Alberta Informatics Circle of Research Excellence; Alberta Heritage Foundation for Medical Research; Alberta Cancer Foundation; Denyse Lajoie Lake Fellowship of the Hotchkiss Brain Institute; Alberta Cancer Research Institute.
Funding Information:
This research was supported by the Hotchkiss Brain Institute, the Alberta Cancer Research Institute, and the Alberta Informatics Circle of Research Excellence (iCORE). J.R.M. is supported by the Alberta Heritage Foundation for Medical Research (AHFMR). S.D. was supported by AHFMR, iCORE, and the Alberta Ingenuity Foundation.
PY - 2010/1/15
Y1 - 2010/1/15
N2 - In glioblastoma (GBM), promoter methylation of the DNA repair gene O6-methylguanine-DNA methyltransferase (MGMT) is associated with benefit from chemotherapy. Correlations between MGMT promoter methylation and visually assessed imaging features on magnetic resonance (MR) have been reported suggesting that noninvasive detection of MGMT methylation status might be possible. Our study assessed whether MGMT methylation status in GBM could be predicted using MR imaging. We conducted a retrospective analysis of MR images in patients with newly diagnosed GBM. Tumor texture was assessed by two methods. First, we analyzed texture by expert consensus describing the tumor borders, presence or absence of cysts, pattern of enhancement, and appearance of tumor signal in T2-weighted images. Then, we applied space-frequency texture analysis based on the S-transform. Tumor location within the brain was determined using automatized image registration and segmentation techniques. Their association with MGMT methylation was analyzed. We confirmed that ring enhancement assessed visually is significantly associated with unmethylated MGMT promoter status (P = 0.006). Texture features on T2-weighted images assessed by the space-frequency analysis were significantly different between methylated and unmethylated cases (P < 0.05). However, blinded classification of MGMT promoter methylation status reached an accuracy of only 71%. There were no significant differences in the locations of methylated and unmethylated GBM tumors. Our results provide further evidence that individual MR features are associated with MGMT methylation but better algorithms for predicting methylation status are needed. The relevance of this study lies on the application of novel techniques for the analysis of anatomical MR images of patients with GBM allowing the evaluation of subtleties not seen by an observer and facilitating the standardization of the methods, decreasing the potential for interobserver bias.
AB - In glioblastoma (GBM), promoter methylation of the DNA repair gene O6-methylguanine-DNA methyltransferase (MGMT) is associated with benefit from chemotherapy. Correlations between MGMT promoter methylation and visually assessed imaging features on magnetic resonance (MR) have been reported suggesting that noninvasive detection of MGMT methylation status might be possible. Our study assessed whether MGMT methylation status in GBM could be predicted using MR imaging. We conducted a retrospective analysis of MR images in patients with newly diagnosed GBM. Tumor texture was assessed by two methods. First, we analyzed texture by expert consensus describing the tumor borders, presence or absence of cysts, pattern of enhancement, and appearance of tumor signal in T2-weighted images. Then, we applied space-frequency texture analysis based on the S-transform. Tumor location within the brain was determined using automatized image registration and segmentation techniques. Their association with MGMT methylation was analyzed. We confirmed that ring enhancement assessed visually is significantly associated with unmethylated MGMT promoter status (P = 0.006). Texture features on T2-weighted images assessed by the space-frequency analysis were significantly different between methylated and unmethylated cases (P < 0.05). However, blinded classification of MGMT promoter methylation status reached an accuracy of only 71%. There were no significant differences in the locations of methylated and unmethylated GBM tumors. Our results provide further evidence that individual MR features are associated with MGMT methylation but better algorithms for predicting methylation status are needed. The relevance of this study lies on the application of novel techniques for the analysis of anatomical MR images of patients with GBM allowing the evaluation of subtleties not seen by an observer and facilitating the standardization of the methods, decreasing the potential for interobserver bias.
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U2 - 10.1016/j.neuroimage.2009.09.049
DO - 10.1016/j.neuroimage.2009.09.049
M3 - Article
C2 - 19796694
AN - SCOPUS:70749119866
SN - 1053-8119
VL - 49
SP - 1398
EP - 1405
JO - NeuroImage
JF - NeuroImage
IS - 2
ER -