Monovoxel &lt;sup&gt;1&lt;/sup&gt;H Magnetic Resonance Spectroscopy in the Progression of Gliomas

“…8 Previous studies have demonstrated the utility of MR spectroscopy in predicting or prognosticating MT and survival of those with LGGs. [9][10][11][12][13][14][15] To the best of our knowledge, the role of MR spectroscopy in diagnosing MT among LGGs with increased contrast enhancement has not been investigated. In the present study, using histopathology as the criterion standard, we aimed to determine the value of MR spectroscopy to diagnose MT in a group of patients who had a prior diagnosis of LGG and an increase in contrast enhancement on follow-up MR imaging.…”

mentioning

confidence: 99%

MRS as an Aid to Diagnose Malignant Transformation in Low-Grade Gliomas with Increasing Contrast Enhancement

Toh¹,

Castillo

Wei

et al. 2020

AJNR Am J Neuroradiol

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BACKGROUND AND PURPOSE: Increased contrast enhancement has been used as a marker of malignant transformation in lowgrade gliomas. This marker has been found to have limited accuracy because many low-grade gliomas with increased contrast enhancement remain grade II. We aimed to investigate whether MR spectroscopy can contribute to the diagnosis of malignant transformation in low-grade gliomas with increased contrast enhancement. MATERIALS AND METHODS: Patients with low-grade gliomas who had contemporaneous MR spectroscopy and histopathology for tumor regions with increased contrast enhancement between 2004 and 2015 were retrospectively reviewed. Clinical data collected were sex and age, Karnofsky Performance Scale, histologic subtypes, isocitrate dehydrogenase 1 mutation status, disease duration, adjuvant therapy, and post-radiation therapy duration. Imaging data collected were contrast-enhancement size, whole-tumor size, MR spectroscopy metabolite ratios, and tumor grades of regions with increased contrast enhancement. Diagnostic values of these factors on malignant transformation of low-grade gliomas were statistically analyzed. RESULTS: A total of 86 patients with 96 MR spectroscopy studies were included. Tumor grades associated with increased contrast enhancement were grade II (n ¼ 42), grade III (n ¼ 27), and grade IV (n ¼ 27). On multivariate analysis, the NAA/Cho ratio was the only significant factor (P , .001; OR, 7.1; 95% CI, 3.2-16.1) diagnostic of malignant transformation. With 0.222 as the cutoff value, the sensitivity, specificity, and accuracy of NAA/Cho for diagnosing malignant transformation were 94.4%, 83.3%, and 89.6%, respectively. CONCLUSIONS: MR spectroscopy complements conventional MR imaging in the diagnosis of malignant transformation in a subgroup of low-grade gliomas with increased contrast enhancement. ABBREVIATIONS: LGG ¼ low-grade glioma; MT ¼ malignant transformation; WHO ¼ World Health Organization L ow-grade gliomas (LGGs) are grade II World Health Organization (WHO) primary brain tumors, accounting for 14.6% of gliomas in population-based studies. 1 LGGs may remain clinically and radiographically stable for years after initial diagnosis and treatment. However, at an unpredictable time, some may show MR imaging features suggestive of disease progression, eg,

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“…For example, NAA/Cho and Cho/Cr ratios are reported in brain tumor studies (31)(32)(33)(34). However, due to the lack of neurons in the U87MG tumors, NAA (Nacetyl aspartate) was not present, precluding use of a NAA/Cho ratio.…”

Section: Discussionmentioning

confidence: 99%

Reproducibility of total choline/water ratios in mouse U87MG xenograft tumors by ¹H‐MRS

Zhu

Fischl

Trowbridge

et al. 2012

Magnetic Resonance Imaging

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Purpose: To evaluate the reproducibility of the measurement of the total choline-to-water ratio, and the effect of repositioning the subject between scans, using 1 H-magnetic resonance spectroscopy in a mouse U87MG xenograft model. Materials and Methods:In vivo single-voxel MR spectra at 7T from xenograft tumors were obtained using both a water-suppressed and a nonwater-suppressed pointresolved spectroscopy (PRESS) sequence. Reproducibility of the total choline/water ratio was evaluated under the conditions of immediate rescan with no change in position of the animal or voxel, immediate reposition, and reposition after 1 or 7 days.Results: Total choline-to-water ratios in U87MG tumor xenografts averaged %0.018 across all of the groups. The average percent difference between the two scans in each condition was always less than %3.0%, and the coefficient of variation was always less than %12%. Bias was unrelated to the testing condition and relatively negligible in magnitude (<3%). Due to heteroscedasticity in the ratios, the limits of agreement were calculated after log transformation of the data and ranged from %12% when animals were maintained in the same position and immediately rescanned to %52% when the two scans were 7 days apart. Conclusion:The total choline-to-water ratio provides a reproducible measure of choline-containing metabolites in subcutaneous U87MG xenograft tumors in mice.

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Monovoxel <sup>1</sup>H Magnetic Resonance Spectroscopy in the Progression of Gliomas

Cited by 21 publications

References 122 publications

The Fornix and Limbic System

The Fornix and Limbic System

MRS as an Aid to Diagnose Malignant Transformation in Low-Grade Gliomas with Increasing Contrast Enhancement

Reproducibility of total choline/water ratios in mouse U87MG xenograft tumors by ¹H‐MRS

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Monovoxel <sup>1</sup>H Magnetic Resonance Spectroscopy in the Progression of Gliomas

Cited by 21 publications

References 122 publications

The Fornix and Limbic System

The Fornix and Limbic System

MRS as an Aid to Diagnose Malignant Transformation in Low-Grade Gliomas with Increasing Contrast Enhancement

Reproducibility of total choline/water ratios in mouse U87MG xenograft tumors by 1H‐MRS

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Reproducibility of total choline/water ratios in mouse U87MG xenograft tumors by ¹H‐MRS