Advancements in Neuroimaging to Unravel Biological and Molecular Features of Brain Tumors

Abstract

In recent years, the clinical assessment of primary brain tumors has been increasingly dependent on advanced magnetic resonance imaging (MRI) techniques in order to infer tumor pathophysiological characteristics, such as hemodynamics, metabolism, and microstructure. Quantitative radiomic data extracted from advanced MRI have risen as potential in vivo noninvasive biomarkers for predicting tumor grades and molecular subtypes, opening the era of “molecular imaging” and radiogenomics. This review presents the most relevant advancements in quantitative neuroimaging of advanced MRI techniques, by means of radiomics analysis, applied to primary brain tumors, including lower-grade glioma and glioblastoma, with a special focus on peculiar oncologic entities of current interest. Novel findings from diffusion MRI (dMRI), perfusion-weighted imaging (PWI), and MR spectroscopy (MRS) are hereby sifted in order to evaluate the role of quantitative imaging in neuro-oncology as a tool for predicting molecular profiles, stratifying prognosis, and characterizing tumor tissue microenvironments. Furthermore, innovative technological approaches are briefly addressed, including artificial intelligence contributions and ultra-high-field imaging new techniques. Lastly, after providing an overview of the advancements, we illustrate current clinical applications and future perspectives.

Hemodynamic Imaging in Cerebral Diffuse Glioma—Part B: Molecular Correlates, Treatment Effect Monitoring, Prognosis, and Future Directions

“…This information, which is crucial in patient management, is currently only available after the analysis of tumor specimens (biopsy/resection). In this respect, advancements in neuroimaging can play a determinant role in inferring the tumor characteristics, metabolism, and micro-structure [ 8 ] but they also provide additional means of correlating the imaging biomarkers to the tumor molecular features pre-operatively, i.e., radiogenomics [ 9 ]. Examples of efforts in this direction include the availability of the Cancer Genome Atlas imaging datasets through the Cancer Imaging Archive ( Last accessed on 21 December 2021).…”

Radiotherapy of High-Grade Gliomas: First Half of 2021 Update with Special Reference to Radiosensitization Studies

“…Advancements in definition of the RT planned target volume (PTV) have been obtained by different MRI techniques such as ultrahigh-field 7-T MRI, diffusion MRI, perfusionweighted imaging, and magnetic resonance spectroscopy, which may also aid for predicting tumor grades and molecular subtypes [47]. PET imaging may also importantly contribute to RT treatment planning [48].…”

Bombesin Receptor Family Activation and CNS/Neural Tumors: Review of Evidence Supporting Possible Role for Novel Targeted Therapy

“…While magnetic resonance imaging (MRI) remains the mainstay for initial and follow-up imaging of CNS/neural tumors and provides important information on tumor location, size, number of lesions, perifocal edema, and contrast enhancement, other aspects of tumor behavior are either not defined or incompletely defined, such as tumor heterogeneity, extent of metabolically active tissue, differentiating treatmentrelated changes from recurrent disease in previously treated patients, and extent of tumor invasion, in some cases (132,(239)(240)(241)(242). Because of these latter limitations, there is increased interest in the development of other imaging approaches, particularly the use of positron emission tomographic (PET) techniques including [ 18 F]Fluorodeoxyglucose (FDG) (132,235,239,243), as well as other nuclear medicine approaches (132,235,243,244).…”