{
  "id": 253093,
  "title": "Magnetic resonance imaging: MGMT, Flair, T1-weighted and T2-weighted",
  "url": "/competitions/rsna-miccai-brain-tumor-radiogenomic-classification/discussion/253093",
  "author_name": "Marília Prata",
  "post_date": "2021-07-15T02:08:26.235000",
  "votes": 11,
  "comment_count": 0,
  "views": 0,
  "content": "<h1>Fluid Attenuated Inversion Recovery (FLAIR)</h1>\n<p>Fluid-attenuated Inversion Recovery (FLAIR) is an MRI sequence with an inversion recovery set to null fluids.</p>\n<p>\"T2 Fluid-Attenuated Inversion Recovery Resection for Glioblastoma Involving Eloquent Brain Areas Facilitated Through Awake Craniotomy and Clinical Outcome\"</p>\n<p>Authors: MingLu; Zheng-haoFu; Xiao-junHe; Jian-kanLu; Xin-qingDeng; De-liuLin; You-mingGu; Yan-fengFan; Ming-yaoLai; JuanLi; Ming-mingYang; Zhong-pingChen</p>\n<p><a href=\"https://doi.org/10.1016/j.wneu.2019.12.130\" target=\"_blank\">https://doi.org/10.1016/j.wneu.2019.12.130</a></p>\n<p>\"Despite evidence that a greater extent of resection (EOR) improves survival, the role of extended resection based on magnetic resonance imaging (MRI) fluid-attenuated inversion recovery (FLAIR) in the prognosis of glioblastoma (GBM) remains controversial. This study aims to investigate the role of additional resection of FLAIR-detected abnormalities and its influence on clinical outcomes of patients with GBM.\"</p>\n<p>\"The threshold for removal of FLAIR abnormalities affecting survival was determined to be 25%. The median OS and PFS were shorter in the group with FLAIR resection &lt;25% compared with the group with FLAIR resection ≥25% (12 months vs. 26 months; P = 0.001 and 6 months vs. 15 months; P = 0.016, respectively). Univariate and multivariate analyses identified tumor location within or near the eloquent brain areas and the 25% threshold for FLAIR EOR as independent factors affecting OS (overall survival) and PFS (progression-free survival).\"</p>\n<p>\"Identifying a feasible threshold for the resection of FLAIR (fluid-attenuated inversion recovery) abnormalities is valuable in improving the survival of patients with GBM (Glioblastoma Multiforme). Extended resection of GBM involving eloquent brain areas was safe when using a combination of AC and SF-guided surgery.\"</p>\n<p><a href=\"https://www.sciencedirect.com/science/article/abs/pii/S1878875019331626\" target=\"_blank\">https://www.sciencedirect.com/science/article/abs/pii/S1878875019331626</a></p>\n<h1>T1 weighted image</h1>\n<p>By Dr Yahya Baba and Dr Jeremy Jones et al.</p>\n<p>\"T1 weighted image (also referred to as T1WI or the \"spin-lattice\" relaxation time) is one of the basic pulse sequences in MRI and demonstrates differences in the T1 relaxation times of tissues.</p>\n<p>A T1WI relies upon the longitudinal relaxation of a tissue's net magnetization vector (NMV). Basically, spins aligned in an external field (B0) are put into the transverse plane by a radiofrequency (RF) pulse. They then slide back toward the original equilibrium of B0. Not all tissues return back to equilibrium in the same amount of time, and a tissue's T1 reflects the amount of time taken for its protons' spins to realign with the main magnetic field (B0).</p>\n<p>T1 weighting tends to have short TE and TR times.\"</p>\n<p><a href=\"https://radiopaedia.org/articles/t1-weighted-image\" target=\"_blank\">https://radiopaedia.org/articles/t1-weighted-image</a></p>\n<h1>T2 weighted image</h1>\n<p>By Dr Ammar Haouimi and Dr Jeremy Jones et al.</p>\n<p>T2 weighted image (T2WI) is one of the basic pulse sequences on MRI. The sequence weighting highlights differences on the T2 relaxation time of tissues.</p>\n<p>Summary</p>\n<p>repetition time (TR): long</p>\n<p>echo time (TE): long</p>\n<p>flip angle: less important than with T1 weighting</p>\n<p>fat: intermediate-bright</p>\n<p>fluid: bright</p>\n<p>Physics</p>\n<p>A T2WI relies upon the transverse relaxation (also known as \"spin-spin\" relaxation) of the net magnetization vector (NMV). T2 weighting tends to require long TE and TR times.</p>\n<p><a href=\"https://radiopaedia.org/articles/t2-weighted-image\" target=\"_blank\">https://radiopaedia.org/articles/t2-weighted-image</a></p>\n<h1>MGMT promoter methylation</h1>\n<p>\"MGMT promoter methylation in malignant gliomas: ready for personalized medicine?\"</p>\n<p>Citation: Weller, M., Stupp, R., Reifenberger, G. et al. MGMT promoter methylation in malignant gliomas: ready for personalized medicine?. Nat Rev Neurol 6, 39–51 (2010). <a href=\"https://doi.org/10.1038/nrneurol.2009.197\" target=\"_blank\">https://doi.org/10.1038/nrneurol.2009.197</a></p>\n<p>\"The DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT) antagonizes the genotoxic effects of alkylating agents. MGMT promoter methylation is the key mechanism of MGMT gene silencing and predicts a favorable outcome in patients with glioblastoma who are exposed to alkylating agent chemotherapy. This biomarker is on the verge of entering clinical decision-making and is currently used to stratify or even select glioblastoma patients for clinical trials. In other subtypes of glioma, such as anaplastic gliomas, the relevance of MGMT promoter methylation might extend beyond the prediction of chemosensitivity, and could reflect a distinct molecular profile.\"</p>\n<p>Key Points</p>\n<p>MGMT (O6-methylguanine-DNA methyltransferase) promoter methylation has become the most powerful molecular prognosticator in malignant gliomas.</p>\n<p>MGMT promoter methylation is predictive for response to alkylating agent chemotherapy in glioblastoma.</p>\n<p>Methylation-specific PCR is the only validated technique to derive prognostic information from determination of the MGMT status.</p>\n<p>The MGMT status has become a parameter for stratification of patients with glioma within clinical trials.</p>\n<p><a href=\"https://www.nature.com/articles/nrneurol.2009.197\" target=\"_blank\">https://www.nature.com/articles/nrneurol.2009.197</a></p>\n<h1>MGMT Promoter Methylation and Gene Expression Levels in Glioblastoma</h1>\n<p>\"MGMT promoter methylation status was a more reliable predictor of susceptibility to adjuvant therapy and prognosis of glioblastoma than were MGMT protein or gene expression levels. Methylation-specific polymerase chain reaction and pyrosequencing methods were both sensitive methods for determining MGMT promoter methylation status using DNA extracted from frozen tissue.\"</p>\n<p><a href=\"https://www.scielo.br/j/clin/a/tzYgxYpz9b6Y54ftcD7bJ6F/?lang=en\" target=\"_blank\">https://www.scielo.br/j/clin/a/tzYgxYpz9b6Y54ftcD7bJ6F/?lang=en</a></p>\n<h1>Abbreviations:</h1>\n<p>HGG = high grade gliomas, T1Gd = T1-weighted gadolinium contrasted, T2-FLAIR = T2 weighted fluid attenuated inversion recovery, ROI = region of interest, CC = contralateral control, CE = contrast enhancing, MRI = magnetic resonance imaging; MRE = magnetic resonance elastography; MNO = Mathematical Neuro-Oncology Lab; PNT = Precision Neurotherapeutics Innovation Program, D = tumor diffusiveness, ⍴ = tumor proliferation, D/⍴ = tumor invasiveness</p>\n<p><a href=\"https://www.biorxiv.org/content/10.1101/2020.11.21.352724v2\" target=\"_blank\">https://www.biorxiv.org/content/10.1101/2020.11.21.352724v2</a></p>",
  "messages": [
    {
      "id": 1388476,
      "postDate": "2021-07-15T02:08:26.237Z",
      "content": "<h1>Fluid Attenuated Inversion Recovery (FLAIR)</h1>\n<p>Fluid-attenuated Inversion Recovery (FLAIR) is an MRI sequence with an inversion recovery set to null fluids.</p>\n<p>\"T2 Fluid-Attenuated Inversion Recovery Resection for Glioblastoma Involving Eloquent Brain Areas Facilitated Through Awake Craniotomy and Clinical Outcome\"</p>\n<p>Authors: MingLu; Zheng-haoFu; Xiao-junHe; Jian-kanLu; Xin-qingDeng; De-liuLin; You-mingGu; Yan-fengFan; Ming-yaoLai; JuanLi; Ming-mingYang; Zhong-pingChen</p>\n<p><a href=\"https://doi.org/10.1016/j.wneu.2019.12.130\" target=\"_blank\">https://doi.org/10.1016/j.wneu.2019.12.130</a></p>\n<p>\"Despite evidence that a greater extent of resection (EOR) improves survival, the role of extended resection based on magnetic resonance imaging (MRI) fluid-attenuated inversion recovery (FLAIR) in the prognosis of glioblastoma (GBM) remains controversial. This study aims to investigate the role of additional resection of FLAIR-detected abnormalities and its influence on clinical outcomes of patients with GBM.\"</p>\n<p>\"The threshold for removal of FLAIR abnormalities affecting survival was determined to be 25%. The median OS and PFS were shorter in the group with FLAIR resection &lt;25% compared with the group with FLAIR resection ≥25% (12 months vs. 26 months; P = 0.001 and 6 months vs. 15 months; P = 0.016, respectively). Univariate and multivariate analyses identified tumor location within or near the eloquent brain areas and the 25% threshold for FLAIR EOR as independent factors affecting OS (overall survival) and PFS (progression-free survival).\"</p>\n<p>\"Identifying a feasible threshold for the resection of FLAIR (fluid-attenuated inversion recovery) abnormalities is valuable in improving the survival of patients with GBM (Glioblastoma Multiforme). Extended resection of GBM involving eloquent brain areas was safe when using a combination of AC and SF-guided surgery.\"</p>\n<p><a href=\"https://www.sciencedirect.com/science/article/abs/pii/S1878875019331626\" target=\"_blank\">https://www.sciencedirect.com/science/article/abs/pii/S1878875019331626</a></p>\n<h1>T1 weighted image</h1>\n<p>By Dr Yahya Baba and Dr Jeremy Jones et al.</p>\n<p>\"T1 weighted image (also referred to as T1WI or the \"spin-lattice\" relaxation time) is one of the basic pulse sequences in MRI and demonstrates differences in the T1 relaxation times of tissues.</p>\n<p>A T1WI relies upon the longitudinal relaxation of a tissue's net magnetization vector (NMV). Basically, spins aligned in an external field (B0) are put into the transverse plane by a radiofrequency (RF) pulse. They then slide back toward the original equilibrium of B0. Not all tissues return back to equilibrium in the same amount of time, and a tissue's T1 reflects the amount of time taken for its protons' spins to realign with the main magnetic field (B0).</p>\n<p>T1 weighting tends to have short TE and TR times.\"</p>\n<p><a href=\"https://radiopaedia.org/articles/t1-weighted-image\" target=\"_blank\">https://radiopaedia.org/articles/t1-weighted-image</a></p>\n<h1>T2 weighted image</h1>\n<p>By Dr Ammar Haouimi and Dr Jeremy Jones et al.</p>\n<p>T2 weighted image (T2WI) is one of the basic pulse sequences on MRI. The sequence weighting highlights differences on the T2 relaxation time of tissues.</p>\n<p>Summary</p>\n<p>repetition time (TR): long</p>\n<p>echo time (TE): long</p>\n<p>flip angle: less important than with T1 weighting</p>\n<p>fat: intermediate-bright</p>\n<p>fluid: bright</p>\n<p>Physics</p>\n<p>A T2WI relies upon the transverse relaxation (also known as \"spin-spin\" relaxation) of the net magnetization vector (NMV). T2 weighting tends to require long TE and TR times.</p>\n<p><a href=\"https://radiopaedia.org/articles/t2-weighted-image\" target=\"_blank\">https://radiopaedia.org/articles/t2-weighted-image</a></p>\n<h1>MGMT promoter methylation</h1>\n<p>\"MGMT promoter methylation in malignant gliomas: ready for personalized medicine?\"</p>\n<p>Citation: Weller, M., Stupp, R., Reifenberger, G. et al. MGMT promoter methylation in malignant gliomas: ready for personalized medicine?. Nat Rev Neurol 6, 39–51 (2010). <a href=\"https://doi.org/10.1038/nrneurol.2009.197\" target=\"_blank\">https://doi.org/10.1038/nrneurol.2009.197</a></p>\n<p>\"The DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT) antagonizes the genotoxic effects of alkylating agents. MGMT promoter methylation is the key mechanism of MGMT gene silencing and predicts a favorable outcome in patients with glioblastoma who are exposed to alkylating agent chemotherapy. This biomarker is on the verge of entering clinical decision-making and is currently used to stratify or even select glioblastoma patients for clinical trials. In other subtypes of glioma, such as anaplastic gliomas, the relevance of MGMT promoter methylation might extend beyond the prediction of chemosensitivity, and could reflect a distinct molecular profile.\"</p>\n<p>Key Points</p>\n<p>MGMT (O6-methylguanine-DNA methyltransferase) promoter methylation has become the most powerful molecular prognosticator in malignant gliomas.</p>\n<p>MGMT promoter methylation is predictive for response to alkylating agent chemotherapy in glioblastoma.</p>\n<p>Methylation-specific PCR is the only validated technique to derive prognostic information from determination of the MGMT status.</p>\n<p>The MGMT status has become a parameter for stratification of patients with glioma within clinical trials.</p>\n<p><a href=\"https://www.nature.com/articles/nrneurol.2009.197\" target=\"_blank\">https://www.nature.com/articles/nrneurol.2009.197</a></p>\n<h1>MGMT Promoter Methylation and Gene Expression Levels in Glioblastoma</h1>\n<p>\"MGMT promoter methylation status was a more reliable predictor of susceptibility to adjuvant therapy and prognosis of glioblastoma than were MGMT protein or gene expression levels. Methylation-specific polymerase chain reaction and pyrosequencing methods were both sensitive methods for determining MGMT promoter methylation status using DNA extracted from frozen tissue.\"</p>\n<p><a href=\"https://www.scielo.br/j/clin/a/tzYgxYpz9b6Y54ftcD7bJ6F/?lang=en\" target=\"_blank\">https://www.scielo.br/j/clin/a/tzYgxYpz9b6Y54ftcD7bJ6F/?lang=en</a></p>\n<h1>Abbreviations:</h1>\n<p>HGG = high grade gliomas, T1Gd = T1-weighted gadolinium contrasted, T2-FLAIR = T2 weighted fluid attenuated inversion recovery, ROI = region of interest, CC = contralateral control, CE = contrast enhancing, MRI = magnetic resonance imaging; MRE = magnetic resonance elastography; MNO = Mathematical Neuro-Oncology Lab; PNT = Precision Neurotherapeutics Innovation Program, D = tumor diffusiveness, ⍴ = tumor proliferation, D/⍴ = tumor invasiveness</p>\n<p><a href=\"https://www.biorxiv.org/content/10.1101/2020.11.21.352724v2\" target=\"_blank\">https://www.biorxiv.org/content/10.1101/2020.11.21.352724v2</a></p>",
      "rawMarkdown": "#Fluid Attenuated Inversion Recovery (FLAIR)\n\nFluid-attenuated Inversion Recovery (FLAIR) is an MRI sequence with an inversion recovery set to null fluids.\n\n\"T2 Fluid-Attenuated Inversion Recovery Resection for Glioblastoma Involving Eloquent Brain Areas Facilitated Through Awake Craniotomy and Clinical Outcome\"\n\nAuthors: MingLu; Zheng-haoFu; Xiao-junHe; Jian-kanLu; Xin-qingDeng; De-liuLin; You-mingGu; Yan-fengFan; Ming-yaoLai; JuanLi; Ming-mingYang; Zhong-pingChen\n\nhttps://doi.org/10.1016/j.wneu.2019.12.130\n\n\"Despite evidence that a greater extent of resection (EOR) improves survival, the role of extended resection based on magnetic resonance imaging (MRI) fluid-attenuated inversion recovery (FLAIR) in the prognosis of glioblastoma (GBM) remains controversial. This study aims to investigate the role of additional resection of FLAIR-detected abnormalities and its influence on clinical outcomes of patients with GBM.\"\n\n\"The threshold for removal of FLAIR abnormalities affecting survival was determined to be 25%. The median OS and PFS were shorter in the group with FLAIR resection <25% compared with the group with FLAIR resection ≥25% (12 months vs. 26 months; P = 0.001 and 6 months vs. 15 months; P = 0.016, respectively). Univariate and multivariate analyses identified tumor location within or near the eloquent brain areas and the 25% threshold for FLAIR EOR as independent factors affecting OS (overall survival) and PFS (progression-free survival).\"\n\n\"Identifying a feasible threshold for the resection of FLAIR (fluid-attenuated inversion recovery) abnormalities is valuable in improving the survival of patients with GBM (Glioblastoma Multiforme). Extended resection of GBM involving eloquent brain areas was safe when using a combination of AC and SF-guided surgery.\"\n\nhttps://www.sciencedirect.com/science/article/abs/pii/S1878875019331626\n\n#T1 weighted image\n\nBy Dr Yahya Baba and Dr Jeremy Jones et al.\n\n\"T1 weighted image (also referred to as T1WI or the \"spin-lattice\" relaxation time) is one of the basic pulse sequences in MRI and demonstrates differences in the T1 relaxation times of tissues.\n\nA T1WI relies upon the longitudinal relaxation of a tissue's net magnetization vector (NMV). Basically, spins aligned in an external field (B0) are put into the transverse plane by a radiofrequency (RF) pulse. They then slide back toward the original equilibrium of B0. Not all tissues return back to equilibrium in the same amount of time, and a tissue's T1 reflects the amount of time taken for its protons' spins to realign with the main magnetic field (B0).\n\nT1 weighting tends to have short TE and TR times.\"\n\nhttps://radiopaedia.org/articles/t1-weighted-image\n\n\n#T2 weighted image\n\nBy Dr Ammar Haouimi and Dr Jeremy Jones et al.\n\nT2 weighted image (T2WI) is one of the basic pulse sequences on MRI. The sequence weighting highlights differences on the T2 relaxation time of tissues.\n\nSummary\n\nrepetition time (TR): long\n\necho time (TE): long\n\nflip angle: less important than with T1 weighting\n\nfat: intermediate-bright\n\nfluid: bright\n\nPhysics\n\nA T2WI relies upon the transverse relaxation (also known as \"spin-spin\" relaxation) of the net magnetization vector (NMV). T2 weighting tends to require long TE and TR times.\n\nhttps://radiopaedia.org/articles/t2-weighted-image\n\n\n#MGMT promoter methylation\n\n\"MGMT promoter methylation in malignant gliomas: ready for personalized medicine?\"\n\nCitation: Weller, M., Stupp, R., Reifenberger, G. et al. MGMT promoter methylation in malignant gliomas: ready for personalized medicine?. Nat Rev Neurol 6, 39–51 (2010). https://doi.org/10.1038/nrneurol.2009.197\n\n\"The DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT) antagonizes the genotoxic effects of alkylating agents. MGMT promoter methylation is the key mechanism of MGMT gene silencing and predicts a favorable outcome in patients with glioblastoma who are exposed to alkylating agent chemotherapy. This biomarker is on the verge of entering clinical decision-making and is currently used to stratify or even select glioblastoma patients for clinical trials. In other subtypes of glioma, such as anaplastic gliomas, the relevance of MGMT promoter methylation might extend beyond the prediction of chemosensitivity, and could reflect a distinct molecular profile.\"\n\nKey Points\n\nMGMT (O6-methylguanine-DNA methyltransferase) promoter methylation has become the most powerful molecular prognosticator in malignant gliomas.\n\nMGMT promoter methylation is predictive for response to alkylating agent chemotherapy in glioblastoma.\n\nMethylation-specific PCR is the only validated technique to derive prognostic information from determination of the MGMT status.\n\nThe MGMT status has become a parameter for stratification of patients with glioma within clinical trials.\n\nhttps://www.nature.com/articles/nrneurol.2009.197\n\n#MGMT Promoter Methylation and Gene Expression Levels in Glioblastoma\n\n\"MGMT promoter methylation status was a more reliable predictor of susceptibility to adjuvant therapy and prognosis of glioblastoma than were MGMT protein or gene expression levels. Methylation-specific polymerase chain reaction and pyrosequencing methods were both sensitive methods for determining MGMT promoter methylation status using DNA extracted from frozen tissue.\"\n\nhttps://www.scielo.br/j/clin/a/tzYgxYpz9b6Y54ftcD7bJ6F/?lang=en\n\n#Abbreviations:\n\nHGG = high grade gliomas, T1Gd = T1-weighted gadolinium contrasted, T2-FLAIR = T2 weighted fluid attenuated inversion recovery, ROI = region of interest, CC = contralateral control, CE = contrast enhancing, MRI = magnetic resonance imaging; MRE = magnetic resonance elastography; MNO = Mathematical Neuro-Oncology Lab; PNT = Precision Neurotherapeutics Innovation Program, D = tumor diffusiveness, ⍴ = tumor proliferation, D/⍴ = tumor invasiveness\n\nhttps://www.biorxiv.org/content/10.1101/2020.11.21.352724v2",
      "votes": 8
    }
  ],
  "comments": [],
  "raw_markdown_by_id": {
    "1388476": "#Fluid Attenuated Inversion Recovery (FLAIR)\n\nFluid-attenuated Inversion Recovery (FLAIR) is an MRI sequence with an inversion recovery set to null fluids.\n\n\"T2 Fluid-Attenuated Inversion Recovery Resection for Glioblastoma Involving Eloquent Brain Areas Facilitated Through Awake Craniotomy and Clinical Outcome\"\n\nAuthors: MingLu; Zheng-haoFu; Xiao-junHe; Jian-kanLu; Xin-qingDeng; De-liuLin; You-mingGu; Yan-fengFan; Ming-yaoLai; JuanLi; Ming-mingYang; Zhong-pingChen\n\nhttps://doi.org/10.1016/j.wneu.2019.12.130\n\n\"Despite evidence that a greater extent of resection (EOR) improves survival, the role of extended resection based on magnetic resonance imaging (MRI) fluid-attenuated inversion recovery (FLAIR) in the prognosis of glioblastoma (GBM) remains controversial. This study aims to investigate the role of additional resection of FLAIR-detected abnormalities and its influence on clinical outcomes of patients with GBM.\"\n\n\"The threshold for removal of FLAIR abnormalities affecting survival was determined to be 25%. The median OS and PFS were shorter in the group with FLAIR resection <25% compared with the group with FLAIR resection ≥25% (12 months vs. 26 months; P = 0.001 and 6 months vs. 15 months; P = 0.016, respectively). Univariate and multivariate analyses identified tumor location within or near the eloquent brain areas and the 25% threshold for FLAIR EOR as independent factors affecting OS (overall survival) and PFS (progression-free survival).\"\n\n\"Identifying a feasible threshold for the resection of FLAIR (fluid-attenuated inversion recovery) abnormalities is valuable in improving the survival of patients with GBM (Glioblastoma Multiforme). Extended resection of GBM involving eloquent brain areas was safe when using a combination of AC and SF-guided surgery.\"\n\nhttps://www.sciencedirect.com/science/article/abs/pii/S1878875019331626\n\n#T1 weighted image\n\nBy Dr Yahya Baba and Dr Jeremy Jones et al.\n\n\"T1 weighted image (also referred to as T1WI or the \"spin-lattice\" relaxation time) is one of the basic pulse sequences in MRI and demonstrates differences in the T1 relaxation times of tissues.\n\nA T1WI relies upon the longitudinal relaxation of a tissue's net magnetization vector (NMV). Basically, spins aligned in an external field (B0) are put into the transverse plane by a radiofrequency (RF) pulse. They then slide back toward the original equilibrium of B0. Not all tissues return back to equilibrium in the same amount of time, and a tissue's T1 reflects the amount of time taken for its protons' spins to realign with the main magnetic field (B0).\n\nT1 weighting tends to have short TE and TR times.\"\n\nhttps://radiopaedia.org/articles/t1-weighted-image\n\n\n#T2 weighted image\n\nBy Dr Ammar Haouimi and Dr Jeremy Jones et al.\n\nT2 weighted image (T2WI) is one of the basic pulse sequences on MRI. The sequence weighting highlights differences on the T2 relaxation time of tissues.\n\nSummary\n\nrepetition time (TR): long\n\necho time (TE): long\n\nflip angle: less important than with T1 weighting\n\nfat: intermediate-bright\n\nfluid: bright\n\nPhysics\n\nA T2WI relies upon the transverse relaxation (also known as \"spin-spin\" relaxation) of the net magnetization vector (NMV). T2 weighting tends to require long TE and TR times.\n\nhttps://radiopaedia.org/articles/t2-weighted-image\n\n\n#MGMT promoter methylation\n\n\"MGMT promoter methylation in malignant gliomas: ready for personalized medicine?\"\n\nCitation: Weller, M., Stupp, R., Reifenberger, G. et al. MGMT promoter methylation in malignant gliomas: ready for personalized medicine?. Nat Rev Neurol 6, 39–51 (2010). https://doi.org/10.1038/nrneurol.2009.197\n\n\"The DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT) antagonizes the genotoxic effects of alkylating agents. MGMT promoter methylation is the key mechanism of MGMT gene silencing and predicts a favorable outcome in patients with glioblastoma who are exposed to alkylating agent chemotherapy. This biomarker is on the verge of entering clinical decision-making and is currently used to stratify or even select glioblastoma patients for clinical trials. In other subtypes of glioma, such as anaplastic gliomas, the relevance of MGMT promoter methylation might extend beyond the prediction of chemosensitivity, and could reflect a distinct molecular profile.\"\n\nKey Points\n\nMGMT (O6-methylguanine-DNA methyltransferase) promoter methylation has become the most powerful molecular prognosticator in malignant gliomas.\n\nMGMT promoter methylation is predictive for response to alkylating agent chemotherapy in glioblastoma.\n\nMethylation-specific PCR is the only validated technique to derive prognostic information from determination of the MGMT status.\n\nThe MGMT status has become a parameter for stratification of patients with glioma within clinical trials.\n\nhttps://www.nature.com/articles/nrneurol.2009.197\n\n#MGMT Promoter Methylation and Gene Expression Levels in Glioblastoma\n\n\"MGMT promoter methylation status was a more reliable predictor of susceptibility to adjuvant therapy and prognosis of glioblastoma than were MGMT protein or gene expression levels. Methylation-specific polymerase chain reaction and pyrosequencing methods were both sensitive methods for determining MGMT promoter methylation status using DNA extracted from frozen tissue.\"\n\nhttps://www.scielo.br/j/clin/a/tzYgxYpz9b6Y54ftcD7bJ6F/?lang=en\n\n#Abbreviations:\n\nHGG = high grade gliomas, T1Gd = T1-weighted gadolinium contrasted, T2-FLAIR = T2 weighted fluid attenuated inversion recovery, ROI = region of interest, CC = contralateral control, CE = contrast enhancing, MRI = magnetic resonance imaging; MRE = magnetic resonance elastography; MNO = Mathematical Neuro-Oncology Lab; PNT = Precision Neurotherapeutics Innovation Program, D = tumor diffusiveness, ⍴ = tumor proliferation, D/⍴ = tumor invasiveness\n\nhttps://www.biorxiv.org/content/10.1101/2020.11.21.352724v2"
  }
}