Advanced MR Techniques for Preoperative Glioma Characterization: Part 1 (original) (raw)
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PubMed, 2019
Cerebral gliomas comprise a heterogeneous group of primary neoplasms of the central nervous system, representing a signifcant cause of cancer morbidity and mortality. Contrast-enhanced magnetic resonance imaging (MRI) is paramount for identifying structural brain abnormalities related to the development of gliomas. Although morphological MRI remains the current standard of care for initial diagnostic workup, surgical planning, monitoring therapy response and surveillance during follow-up, it is rather diffcult to define tumor grade and boundaries and to assess response to radiochemotherapy solely by contrast-enhancement, due to a variety of factors influencing blood-brain barrier (BBB) permeability and contrast agent distribution. The nature of a lesion lies beyond often misleading gross structural patterns, down to the cellular and molecular level, hence the imaging techniques of advanced multimodal MRI and positron emission tomography (PET) have emerged to provide critical non-invasive insight into the underlying biology of primary brain cancer. Out of the various PET radiotracers, labeled amino acids are of particular significance due to their non-dependency on BBB disruption to reach glioma cells and their excellent tumor-to-background contrast. After discussing the basic imaging principles of MR perfusion, diffusion, spectroscopy and PET in glioma, this review focuses on the correlative imaging with amino acid PET and advanced MRI techniques in tumor grading and staging, in guiding stereotactic biopsy and surgical excision and in assessing therapy response, post-therapy surveillance and prognosis. Lastly, a reference is made on the expanding availability of integrated PET/MRI systems and the resulting benefits of simultaneous image acquisition.
Advanced Magnetic Resonance Imaging in the Evaluation of Treated Glioblastoma: A Pictorial Essay
Cancers
MRI plays a key role in the evaluation of post-treatment changes, both in the immediate post-operative period and during follow-up. There are many different treatment’s lines and many different neuroradiological findings according to the treatment chosen and the clinical timepoint at which MRI is performed. Structural MRI is often insufficient to correctly interpret and define treatment-related changes. For that, advanced MRI modalities, including perfusion and permeability imaging, diffusion tensor imaging, and magnetic resonance spectroscopy, are increasingly utilized in clinical practice to characterize treatment effects more comprehensively. This article aims to provide an overview of the role of advanced MRI modalities in the evaluation of treated glioblastomas. For a didactic purpose, we choose to divide the treatment history in three main timepoints: post-surgery, during Stupp (first-line treatment) and at recurrence (second-line treatment). For each, a brief introduction, a ...
MRI in treatment of adult gliomas
The Lancet Oncology, 2005
The introduction of MRI into clinical practice has been among the most important of all advances in the care of patients with brain tumours. The crucial roles of neuroimaging in neuro-oncology include refinement of preoperative differential diagnosis, precise anatomical localisation for operative planning (figure 1), detection of response to treatment and of tumour progression, and recognition of side-effects that are treatment related. However, there are many unsolved difficulties in the use of MRI in neuro-oncology. New techniques that allow analysis of the chemical composition of tumour tissue, capillary density, and the diffusion of water, have great potential but are not yet well validated. The specialty of molecular imaging is expanding rapidly, although only in the preclinical setting. Here we review the status of these techniques and other issues in neuro-oncology. Correlation between imaging appearance and histological features of gliomas
Magnetic Resonance Imaging of Gliomas
Advances in the Biology, Imaging and Therapies for Glioblastoma, 2011
Brain cancer is a life threatening neurological disorder in which malignant cells, grow, proliferate and invade the original cerebral structures of the host, hampering seriously adequate brain function. Malignant cells generate eventually a dedifferentiated tumoral mass that interferes with vital brain functions as sensory and motor activations, memory and perception and neuroendocrine regulation, among others. The fully developed tumoral mass consumes a significant part of cerebral volume resulting in cerebral compression and serious neurological impairments, such as vision or hearing disturbances and eventually lethal cerebrovascular complications. Most brain tumors remain asymptomatic during early development, revealing their symptoms and lethal nature only at later stages. Therapy is facilitated many times by an early finding, a circumstance making the neuroimaging approaches particularly useful in the detection and handling of these lesions. In the last decades, Magnetic Resonance Imaging (MRI) approaches have evolved into the most powerful and versatile imaging tool for brain tumor diagnosis, prognosis, therapy evaluation, monitoring of disease progression and planning of neurosurgical strategies. MRI methods enable the non invasive assessment of glioma morphology and functionality providing a point of likeness into histopathological grading of the tumor and helping in this way a more successful patient management. This impressive evolution is based not only for the high resolution and quality of the anatomical images obtained, but on the additional possibilities to achieve quantitative functional information on tumoral physiopathology and its repercussions in the sensorial, motor and integrative functions through the brain. The use of conventional paramagnetic or superparamagnetic contrast media allows for the identification of areas with blood-brain barrier (BBB) disruption and the recent molecular imaging approaches enable researchers to visualize molecular events associated to tumor proliferation and invasion, bringing the potentials of diagnostic imaging to the cellular and molecular aspects of tumor biology. Moreover, functional MRI approaches as performed in the clinic are endowed with the potential to detect and characterize the earliest neoangiogenic, metabolic and hemodynamic alterations induced by the neoplasm. Several advanced magnetic resonance (MR) methodologies have been proposed in the last years to assess the functional competence in healthy and pathologic brain tissue. Diffusion and perfusion MRI are probably the two main approaches that have reached a relevant clinical role
The neuroradiology journal, 2013
A significant number of nonenhancing (NE) gliomas are reported to be malignant. The purpose of this study was to compare the value of advanced MR imaging techniques, including T2*-dynamic susceptibility contrast PWI (DSC-PWI) and proton magnetic resonance spectroscopy ((1)HMRS) in the evaluation of NE gliomas. Twenty patients with NE gliomas underwent MRI including DSC-PWI and (1)HMRS. The relative CBV (rCBV) measurements were obtained from regions of maximum perfusion. The peak ratios of choline/creatine (Cho/Cr) and myo-inositol/creatine (mIns/Cr) were measured at a TE of 30 ms. Demographic features, tumor volumes, and PWI- and (1)HMRS-derived measures were compared between low-grade gliomas (LGGs) and high-grade gliomas (HGGs). In addition, the association of initial rCBV ratio with tumor progression was evaluated in LGGs. No significant difference was noted in age, sex or tumor size between LGGs and HGGs. Cho/Cr ratios were significantly higher in HGGs (1.7±0.63) than in LGGs (1...
Journal of the Medical Association of Thailand = Chotmaihet thangphaet, 2013
To evaluate the usefulness of advanced MRI techniques in differentiating high-grade (HGG) from low-grade gliomas (LGG). Sixty-four patients with suspected gliomas were prospectively evaluated by conventional and advanced MRI studies including MR spectroscopy (MRS), diffusion tensor imagining (DTI), and dynamic susceptibility contrast (DSC) MRI. The parametric measurements of metabolic profile, cerebral blood volume, flow (CBV, CBF), apparent diffusion coefficient (ADC), fractional anisotropy, and their ratios by internal normalization were analyzed to differentiate LGG from HGG. Histopathologic findings were used as the gold standard. Forty-three cases with pathologically-proven gliomas were included The best discriminating features between HGG and LGG were CBV and CBF of the solid tumoral region (p < 0.05) whereas the minADC/corpus callosum ratio for DTI and the ratio of Cho/Cr for MRS of the solid tumoral region provided the best diagnostic performance (p < 0.05). With a pre...
Advanced Imaging Techniques for Newly Diagnosed and Recurrent Gliomas
Frontiers in Neuroscience
Management of gliomas following initial diagnosis requires thoughtful presurgical planning followed by regular imaging to monitor treatment response and survey for new tumor growth. Traditional MR imaging modalities such as T1 post-contrast and T2-weighted sequences have long been a staple of tumor diagnosis, surgical planning, and post-treatment surveillance. While these sequences remain integral in the management of gliomas, advances in imaging techniques have allowed for a more detailed characterization of tumor characteristics. Advanced MR sequences such as perfusion, diffusion, and susceptibility weighted imaging, as well as PET scans have emerged as valuable tools to inform clinical decision making and provide a non-invasive way to help distinguish between tumor recurrence and pseudoprogression. Furthermore, these advances in imaging have extended to the operating room and assist in making surgical resections safer. Nevertheless, surgery, chemotherapy, and radiation treatment ...
Translational oncology, 2018
The goal of this research was to elucidate the relationship between WHO 2016 molecular classifications of newly diagnosed, nonenhancing lower grade gliomas (LrGG), tissue sample histopathology, and magnetic resonance (MR) parameters derived from diffusion, perfusion, and H spectroscopic imaging from the tissue sample locations and the entire tumor. A total of 135 patients were scanned prior to initial surgery, with tumor cellularity scores obtained from 88 image-guided tissue samples. MR parameters were obtained from corresponding sample locations, and histograms of normalized MR parameters within the T2 fluid-attenuated inversion recovery lesion were analyzed in order to evaluate differences between subgroups. For tissue samples, higher tumor scores were related to increased normalized apparent diffusion coefficient (nADC), lower fractional anisotropy (nFA), lower cerebral blood volume (nCBV), higher choline (nCho), and lower N-acetylaspartate (nNAA). Within the T2 lesion, higher t...