RESUMO
OBJECTIVE: To evaluate whether apparent diffusion coefficient (ADC) values can predict the status of MGMT of glioblastoma multiforme (GBM) and correlate with overall survival (OS) and progression-free survival (PFS). METHODS: This retrospective study included 47 patients with pathologically proven glioblastoma. All of them underwent MR DWI study before surgery (mean time 1 week) and the status of methylguanine-DNA-methyltransferase (MGMT) promoter methylation was searched for. Minimum apparent diffusion coefficient (ADC) values were evaluated. OS and PSF parameters were calculated, and Student's t-test, Kaplan-Meier curves, linear and Cox regression were performed. RESULTS: Twenty-five patients showed positive methylation of the MGMT promoter. Patients showing MGMT promoter methylation had higher minimum ADC values, and they survived longer than those without MGMT promoter methylation. The median ADCmin value of 0.80 represents the cutoff value able to distinguish between methylated and un-methylated patients. Patients showing minimum ADC values higher than 0.80 survived longer than patients with minimum ADC values lower than 0.80. A linear correlation between minimum ADC values vs. the OS and PFS was observed. CONCLUSIONS: Minimum ADC values in glioblastoma multiforme could be used as a preoperative parameter to estimate the status of MGMT promoter methylation and the survival of patients.
Assuntos
Neoplasias Encefálicas/diagnóstico , Neoplasias Encefálicas/mortalidade , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/genética , Imagem de Difusão por Ressonância Magnética/métodos , Glioblastoma/diagnóstico , Glioblastoma/mortalidade , Proteínas Supressoras de Tumor/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Análise de Variância , Neoplasias Encefálicas/genética , Estudos de Coortes , Metilação de DNA , Intervalo Livre de Doença , Feminino , Regulação Neoplásica da Expressão Gênica , Glioblastoma/genética , Glioblastoma/terapia , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Prognóstico , Regiões Promotoras Genéticas , Modelos de Riscos Proporcionais , Curva ROC , Estudos Retrospectivos , Medição de Risco , Análise de SobrevidaRESUMO
Magnetic resonance imaging (MRI) with a dynamic susceptibility contrast perfusion-weighted imaging (DSC-PWI) sequence to study brain tumours provides information on the haemodynamic characteristics of the neoplastic tissue. Brain perfusion maps and calculation of perfusion parameters, such as relative cerebral blood flow (rCBF), relative cerebral blood volume (rCBV) and mean transit time (MTT) allow assessment of vascularity and angiogenesis within tumours of the central nervous system (CNS), thus providing additional information to conventional MRI sequences. Although DSC-PWI has long been used, its clinical use in the study of brain tumours in daily clinical practice is still to be defined. The aim of this review was to analyse the application of perfusion MRI in the study of brain tumours by summarising our personal experience and the main results reported in the literature.