A meta-analysis of studies using MR spectroscopy for evaluating suspicious lesions after radiation therapy of primary brain tumors

Despite major advances in the study of the brain, investigations on neurochemistry in vivo still lack the solid ground of more established methods, such as structural and functional magnetic resonance imaging. Proton magnetic resonance spectroscopy (MRS) is a technique that might potentially fill in this gap. Nevertheless, studies using this approach feature great methodological heterogeneity, such as varying voxel of choice, differences on emphasized metabolites, and absence of a standardized unit. In this study, we present a methodology for creating a systematic review and meta-analysis for this kind of scientific evidence using the prototypical case of attention-deficit/hyperactivity disorder. Systematic review registration: International Prospective Register of Systematic Reviews (PROSPERO), CRD42018112418.

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“…While most works screen for all the main proton MRS molecules, 36,37,[39][40][41] some choose to focus on specific frequency ranges. 38 We…”

Section: Discussionmentioning

confidence: 99%

Attention-deficit/hyperactivity disorder and brain metabolites from proton magnetic resonance spectroscopy: a systematic review and meta-analysis protocol

Vidor¹,

Panzenhagen²,

Martins

et al. 2021

Trends Psychiatry Psychother

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“…Magnetic resonance spectroscopy and MRSI are now among the key modalities for nearly all aspects of brain tumor diagnostics and management for both the adult and pediatric populations. This includes initial diagnosis [82], tumor characterization [85] and grading [88], treatment planning in RT [89], surgical guidance [90], as well post-therapeutic follow-up [91][92][93].…”

Section: Primary Brain Tumorsmentioning

confidence: 99%

“…A notable example is that recurrent primary brain tumors are quite often misclassified as radiation necrosis, and vice verse, according to meta-analysis from Refs. [91][92][93]. Another example of great importance for PCM is to distinguish non-tumorous cerebral hypoxia/ischemia from brain tumors.…”

Section: Primary Brain Tumorsmentioning

confidence: 99%

Review of recent applications of the conventional and derivative fast Padé transform for magnetic resonance spectroscopy

Belkić

2019

J Math Chem

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This review is on the fast Padé transform (FPT) for magnetic resonance spectroscopy (MRS). It is structured into two portions. Firstly, we give an introductory overview, emphasizing the conceptual framework. Secondly, we cover the specific, concrete accomplishments with detailed analysis and selected illustrations. Key advances have been achieved by the FPT for MRS in the most recent period. These consist of direct applications of the FPT to time signals encoded by in vivo MRS from tumorous tissues. We focus on the robust and comprehensive Padé-based solutions for the thorniest problems (overlapping resonances, resolution, noise) that have hampered progress of in vivo MRS for a very long time. Both parametric and non-parametric aspects of signal processing in the FPT are thoroughly covered. The FPT, as a parameter estimator, solves exactly the quantification problem by reconstructing the positions, widths, heights and phases of all the physical peaks. This gives the component lineshapes of all the true resonances. The non-parametric FPT, as a shape estimator, has thus far predicted the total lineshapes alone without separating the individual components. Finally, we discuss the most recent advances in signal processing for MRS using the derivative fast Padé transform (dFPT). This upgrade is of utmost importance, as the dFPT exactly reconstructs all the peak parameters for every physical resonance by carrying out estimation of total shape spectra alone. The derivative operator within the dFPT narrows the linewidths and concomitantly enhances the peak heights, while simultaneously suppressing noise. This leads to separation of overlapping peaks, resolution improvement and noise reduction. Far-reaching ramifications of such an achievement within MRS are highlighted with the prospects for further explorations to the benefit particularly of cancer medicine.

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“…Namely, within the FFT neuro-diagnostics through MRS/MRSI have often been reduced to semi-quantitative approaches based upon a very small number of metabolites and/or their ratios. Within radiation neuro-oncology, our recent meta-analysis (39) revealed that by using metabolite ratios, a substantial percentage of recurrent primary brain tumors and radiation necrosis were misclassified. The FPT applied to in vitro MRS time signals encoded from normal human brain achieves markedly superior resolution compared to the FFT, and can identify and precisely quantify at least 25 metabolites (16)(17)(18)40).…”

Section: Neuro-oncologymentioning

confidence: 99%

Strategic Steps for Advanced Molecular Imaging with Magnetic Resonance-Based Diagnostic Modalities

Belkić

2015

Technol Cancer Res Treat

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With the rapidly-expanding sophistication in our understanding of cancer cell biology, molecular imaging offers a critical bridge to oncology. Molecular imaging through magnetic resonance spectroscopy (MRS) can provide information about many metabolites at the same time. Since MRS entails no ionizing radiation, repeated monitoring, including screening can be performed. However, MRS via the fast Fourier transform (FFT) has poor resolution and signal-to-noise ratio (SNR). Moreover, subjective and non-unique (ambiguous) fittings of FFT spectra cannot provide reliable quantification of clinical usefulness. In sharp contrast, objective and unique (unambiguous) signal processing by the fast Padé transform (FPT) can increase resolution and retrieve the true quantitative metabolic information. To illustrate, we apply the FPT to in vitro MRS data as encoded from malignant ovarian cyst fluid and perform detailed analysis. This problem area is particularly in need of timely diagnostics by more advanced modalities, such as high-resolution MRS, since conventional methods usually detect ovarian cancers at late stages with poor prognosis, whereas at an early stage the prognosis is excellent. The reliability and robustness of the FPT is assessed for time signals contaminated with varying noise levels. In the presence of higher background noise, all physical metabolites were unequivocally identified and their concentrations precisely extracted, using small fractions of the total signal length. Via the "signal-noise separation" concept alongside the "stability test", all non-physical information was binned, such that fully denoised spectra were generated. These results imply that a reformulation of data acquisition is needed, as guided by the FPT in MRS, since a small number of short transient time signals can provide high resolution and good SNR. This would enhance the diagnostic accuracy of MRS and shorten examination times, thereby improving efficiency and cost-effectiveness of this high throughput cancer diagnostic modality. Such advantages could be particularly important for more effective ovarian cancer detection, as well as more broadly for improved diagnostics and treatment within oncology.

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A meta-analysis of studies using MR spectroscopy for evaluating suspicious lesions after radiation therapy of primary brain tumors

Cited by 10 publications

References 39 publications

Attention-deficit/hyperactivity disorder and brain metabolites from proton magnetic resonance spectroscopy: a systematic review and meta-analysis protocol

Attention-deficit/hyperactivity disorder and brain metabolites from proton magnetic resonance spectroscopy: a systematic review and meta-analysis protocol

Review of recent applications of the conventional and derivative fast Padé transform for magnetic resonance spectroscopy

Strategic Steps for Advanced Molecular Imaging with Magnetic Resonance-Based Diagnostic Modalities

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