Added value of advanced over conventional magnetic resonance imaging in grading gliomas and other primary brain tumors

Abstract

BackgroundAlthough conventional MR imaging (MRI) is the most widely used non-invasive technique for brain tumor grading, its accuracy has been reported to be relatively low. Advanced MR techniques, such as perfusion-weighted imaging (PWI), diffusion-weighted imaging (DWI), and magnetic resonance spectroscopy (MRS), could predict neoplastic histology, but their added value over conventional MRI is still open to debate.MethodsWe prospectively analyzed 129 patients diagnosed with primary brain tumors (118 gliomas) classified as low-grade in 30 cases and high-grade in 99 cases.ResultsSignificant differences were obtained in high-grade tumors for conventional MRI variables (necrosis, enhancement, edema, hemorrhage, and neovascularization); high relative cerebral blood volume values (rCBV), low relative apparent diffusion coefficients (rADC), high ratio of N-acetyl-aspartate/creatine at short echo time (TE) and high choline/creatine at long TE. Among conventional MRI variables, the presence of enhancement and necrosis were demonstrated to be the best predictors of high grade in primary brain tumors (sensitivity 95.9%; specificity 70%). The best results in primary brain tumors were obtained for enhancement, necrosis, and rADC (sensitivity 98.9%; specificity 75.9%). Necrosis and enhancement were the only predictors of high grade in gliomas (sensitivity 97.6%; specificity 76%) when all the magnetic resonance variables were combined.ConclusionsMRI is highly accurate in the assessment of tumor grade. The combination of conventional MRI features with advanced MR variables showed only improved tumor grading by adding rADC to conventional MRI variables in primary brain tumors.

Diffusion-Weighted MRI Reflects Proliferative Activity in Primary CNS Lymphoma

“…This is in accordance with the work of Guzmán-De-Villoria et colleagues[21], who found a trend of correlation between low ADCmean values and Ki-67expression in glioma and other brain tumors. We assume that the relationship between ADC values and Ki-67 expression in gliomas is more difficult to prove, since the tissue architecture of glioma is more heterogeneous and the resulting ADC values exhibit a greater degree of variation compared to PCNSL.…”

Quantification of apparent diffusion coefficient and relative cerebral blood volume for analysis concerning gender and age as determinant factors in glioma prospect

“…The discernment between types and grading of gliomas were based on morphological (MR) imaging and metabolic (MRS) imaging [1,8]. However, in pursuance of making comparisons between groups (males/females, younger/older than 45 years old), this research utilized ADC values and rCBV due to the specificity of microscopic alterations arising in gliomas [6,7,[15][16][17]21].…”

“…World Health Organization (WHO) provides a classification of gliomas into grades, from 1 to 4, stating the aggressiveness of the tumor (grade I being the less harmful). Although the classification clearly differentiates between the grades, in practical medicine, reality often proves that there are mixed gliomas with an elevated level of malignancy intra lesion but with lower level at periphery [1]. For that reason, this research will consider high grade gliomas and encompass the following levels: II/III, III, III/IV and IV [5,7].…”

“…One of them is magnetic resonance spectroscopy (MRS), which proved its feasibility due to accurate values of metabolic changes that occur in tumor -appearing tissues [4,8]. The main disadvantage of MRS stands to be the long scanning time and elaborate post processing [1]. Other magnetic resonance imaging techniques, which provide information about the cellularity and vascularization of tumors, are perfusion -weighted imaging (from which derives rCBV) and diffusion -weighted imaging (from which we extract ADC values) [2,3,4].…”

Magnetic Resonance Spectroscopy and Single-Photon Emission Computed Tomography in the Evaluation of Cerebral Tumors: A Case Report

“…Since then and for the last decades, MRS combined with other magnetic resonance imaging (MRI) advanced techniques such as perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) has become a routine pre-surgical evaluation method of intracranial tumors [2-10]. In addition, MRS is popularized among scientists as a valuable diagnostic modality in several other pathological conditions such as hypoxia-ischemia in neonates, head trauma, epilepsy, leukodystrophies and metabolic diseases [11, 12].…”