EXTH-20. HYPERPOLARIZED [2-13C] PYRUVATE TO [5-13C] GLUTAMATE AS BIOMARKERS OF IDH1 MUTANT GLIOMA RESPONSE TO TEMOZOLOMIDE THERAPY

Abstract Low-grade gliomas, driven by mutations in the cytosolic isocitrate dehydrogenase 1 (IDH1) gene, are less aggressive than primary glioblastoma, but nonetheless always recur and ultimately lead to patient death. The treatment of IDH1 mutant patients with Temozolomide (TMZ) improves survival, but there remains a need for complementary imaging methods to assess response to therapy at an early time point. The goal of this study was, therefore, to determine the value of magnetic resonance spectroscopy (MRS)-based metabolic imaging biomarkers for detection of response to treatment. To this end we investigated NHA and U87 cells expressing IDH1 R132H mutant gene (NHAIDHmut and U87IDHmut) and first used 1H MRS combined with chemometrics to examined the metabolic alterations that occurred following treatment with the IC50 value of TMZ. We observed a significant increase in 2-hydroxyglutarate (2-HG), glutamate, and glutamine, and metabolic pathway analysis showed tricarboxylic acid (TCA) cycle and pyruvate metabolism to be significantly altered pathways following TMZ treatment compared to DMSO control. To confirm changes in TCA cycle flux and to assess the metabolic pathways contributing to the increase in 2-HG and glutamate/glutamine, cells were then labelled with [1-13C] glucose and [3-13C] glutamine. Our data indicated that both glucose flux via the TCA to glutamate and 2HG, and the contribution of glutamine to glutamate and 2HG were increased following TMZ treatment. Finally, we used hyperpolarized 13C-MRS to dynamically probe the metabolism of hyperpolarized [2-13C] pyruvate and its conversion to hyperpolarized [5-13C] glutamate via the TCA cycle. Consistent with our previous findings, we observed that hyperpolarized [5-13C] glutamate synthesis was significantly higher in TMZ-treated cells compared to controls. Collectively, our findings identify 1H MRS-detectable elevation of 2-HG and glutamate/glutamine as well as hyperpolarized 13C-MRS-detectable [5-13C] glutamate production from [2-13C] pyruvate as potentially translatable metabolic biomarkers of response to TMZ therapy in mutant IDH1 glioma.

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EXTH-46. MRS BASED BIOMARKERS OF IDH1 MUTANT GLIOMA RESPONSE TO THE IDH INHIBITOR BAY-1436032

Neuro-Oncology ◽

10.1093/neuonc/noab196.685 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi173-vi173

Author(s):

Donghyun Hong ◽

Noriaki Minami ◽

Céline Taglang ◽

Georgios Batsios ◽

Anne Marie Gillespie ◽

...

Keyword(s):

Animal Models ◽

Animal Studies ◽

Response To Treatment ◽

Resonance Spectroscopy ◽

Low Grade ◽

Isocitrate Dehydrogenase 1 ◽

1H Mrs ◽

Hyperpolarized 13C ◽

13C Mrs ◽

Mutant Idh1

Abstract Gliomas are the most prevalent type of brain tumor in the central nervous system. Mutations in the cytosolic enzyme isocitrate dehydrogenase 1 (IDH1) are a common feature of primary low-grade gliomas, catalyzing the conversion of α-ketoglutarate (αKG) to the oncometabolite 2-hydroxyglutarate (2HG), and mutant IDH1 is a therapeutic target for these tumors. Several mutant IDH inhibitors are currently in clinical trials, nonetheless, complementary non-invasive early biomarkers to assess drug delivery and potential therapeutic response are still needed. The goal of this study was therefore to determine the potential of 1H and hyperpolarized 13C magnetic resonance spectroscopy (MRS)-based biomarkers as indicators of mutant IDH1 low-grade glioma response to treatment with the clinically-relevant IDH1 inhibitor BAY-1436032 in cells and animal models. Immortalized human astrocytes engineered to express mutant IDH1 were treated with 500nM (IC50 value) of BAY-1436032 and BT257 tumors implanted in rats were treated with 150mg/kg of BAY-1436032. To assess steady-state metabolite levels, 1H MRS spectra were acquired on a 500 MHz MRS cancer for cells and a 3 T scanner for animal studies. To assess metabolic fluxes, we used hyperpolarized 13C MRS and probed the fate of hyperpolarized [1-13C]αKG. 1H MRS showed a significant decrease in 2HG as well as a significant increase in glutamate (Glu) and phosphocholine (PCh) following BAY-1436032 treatment in both cell and animal models compared to controls. Furthermore, hyperpolarized 13C MRS showed that hyperpolarized 2HG production from hyperpolarized [1-13C]αKG was decreased and hyperpolarized glutamate production from hyperpolarized [1-13C]αKG was increased in the BAY-1436032 treated groups compared to controls. These findings are consistent with our previous study, which investigated the MRS-detectable consequences of two other mutant IDH inhibitors: AG120 and AG881. Collectively, our work identifies translatable MRS-based metabolic biomarkers of mutant IDH1 inhibition.

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TAMI-40. PEDIATRIC H3K27M MUTANT GLIOMAS UNDERGO METABOLIC REPROGRAMMING THAT CAN BE LEVERAGED FOR NON-INVASIVE METABOLIC IMAGING

Neuro-Oncology ◽

10.1093/neuonc/noab196.824 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi206-vi207

Author(s):

Meryssa Tran ◽

Georgios Batsios ◽

Céline Taglang ◽

Anne Marie Gillespie ◽

Javad Nazarian ◽

...

Keyword(s):

Magnetic Resonance ◽

Phospholipid Metabolism ◽

Metabolic Reprogramming ◽

Metabolic Imaging ◽

Resonance Spectroscopy ◽

1H Mrs ◽

Hyperpolarized 13C ◽

Non Invasive ◽

13C Mrs

Abstract Diffuse midline gliomas (DMGs) are a universally lethal form of childhood cancer. The infiltrative nature of DMGs makes them difficult to visualize by conventional magnetic resonance imaging. Genomics studies indicate that DMGs are driven by unique histone H3K27M mutations that result in broad epigenetic dysregulation. Many of the resulting changes in gene expression have the potential to induce metabolic reprogramming, which has been identified as a hallmark of cancer. The goal of this study was to dissect metabolic reprogramming in preclinical DMG models in order to identify novel magnetic resonance spectroscopy (MRS)-detectable metabolic biomarkers that can be exploited for non-invasive imaging. First, we used 1H-MRS, which reports on steady-state metabolism, to examine H3K27M mutant SF7761 cells and H3 wild-type normal human astrocytes (NHA). Lactate, glutathione and phosphocholine, which are involved in glycolysis, redox and phospholipid metabolism respectively, were elevated in SF7761 cells relative to NHAs. Mechanistically, these metabolic alterations were associated with upregulation of key enzymes including hexokinase 2, glutamate cysteine ligase and choline kinase a. Importantly, in vivo 1H-MRS showed elevated lactate, glutathione and total choline (combined signal from choline, phosphocholine and glycerophosphocholine) in mice bearing orthotopic SF7761 tumors relative to tumor-free controls. We then examined alterations in dynamic metabolic pathways in our models. Using thermally-polarized 13C-MRS, we identified elevated production of [2-13C]-lactate from [2-13C]-glucose in SF7761 cells relative to NHAs. Hyperpolarized 13C-MRS is a method of enhancing the 13C-MR signal such that metabolic fluxes can be interrogated with high sensitivity. Hyperpolarized [1-13C]-pyruvate flux to [1-13C]-lactate non-invasively monitors glycolysis and is in clinical trials in adult glioma patients. Importantly, hyperpolarized [1-13C]-pyruvate metabolism to lactate was elevated in SF7761 cells relative to NHAs. Collectively, our studies suggest that H3K27M mutant DMGs undergo reprogramming of glucose, redox and phospholipid metabolism that can be leveraged for non-invasive 1H- and hyperpolarized 13C-MRS-based imaging.

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Non-Invasive Differentiation of M1 and M2 Activation in Macrophages Using Hyperpolarized 13C MRS of Pyruvate and DHA at 1.47 Tesla

Metabolites ◽

10.3390/metabo11070410 ◽

2021 ◽

Vol 11 (7) ◽

pp. 410

Author(s):

Kai Qiao ◽

Lydia M. Le Page ◽

Myriam M. Chaumeil

Keyword(s):

Macrophage Activation ◽

Dehydroascorbic Acid ◽

Metabolic Reprogramming ◽

Metabolic Imaging ◽

Alternative Activation ◽

Resonance Spectroscopy ◽

1H Mrs ◽

Central Process ◽

Hyperpolarized 13C ◽

13C Mrs

Macrophage activation, first generalized to the M1/M2 dichotomy, is a complex and central process of the innate immune response. Simply, M1 describes the classical proinflammatory activation, leading to tissue damage, and M2 the alternative activation promoting tissue repair. Given the central role of macrophages in multiple diseases, the ability to noninvasively differentiate between M1 and M2 activation states would be highly valuable for monitoring disease progression and therapeutic responses. Since M1/M2 activation patterns are associated with differential metabolic reprogramming, we hypothesized that hyperpolarized 13C magnetic resonance spectroscopy (HP 13C MRS), an innovative metabolic imaging approach, could distinguish between macrophage activation states noninvasively. The metabolic conversions of HP [1-13C]pyruvate to HP [1-13C]lactate, and HP [1-13C]dehydroascorbic acid to HP [1-13C]ascorbic acid were monitored in live M1 and M2 activated J774a.1 macrophages noninvasively by HP 13C MRS on a 1.47 Tesla NMR system. Our results show that both metabolic conversions were significantly increased in M1 macrophages compared to M2 and nonactivated cells. Biochemical assays and high resolution 1H MRS were also performed to investigate the underlying changes in enzymatic activities and metabolite levels linked to M1/M2 activation. Altogether, our results demonstrate the potential of HP 13C MRS for monitoring macrophage activation states noninvasively.

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CBMT-41. IMAGING A HALLMARK OF CANCER: HYPERPOLARIZED 13C-MAGNETIC RESONANCE SPECTROSCOPY CAN NON-INVASIVELY MONITOR TERT EXPRESSION IN LOW-GRADE GLIOMAS IN VIVO

Neuro-Oncology ◽

10.1093/neuonc/noz175.163 ◽

2019 ◽

Vol 21 (Supplement_6) ◽

pp. vi42-vi42

Author(s):

Pavithra Viswanath ◽

Georgios Batsios ◽

Anne Marie Gillespie ◽

Russell O Pieper ◽

Sabrina Ronen

Keyword(s):

Lactate Production ◽

Metabolic Imaging ◽

Imaging Biomarkers ◽

Resonance Spectroscopy ◽

Low Grade ◽

Normal Brain ◽

Non Invasive ◽

Glucose Flux ◽

Tert Expression

Abstract Telomerase reverse transcriptase (TERT) expression is a hallmark of cancer, including in primary glioblastomas and low-grade oligodendrogliomas. Since TERT is essential for glioma proliferation and is an attractive therapeutic target, metabolic imaging of TERT status can inform on tumor progression and response to therapy. To that end, the goal of this study was to identify non-invasive, translational, hyperpolarized 13C-magnetic resonance spectroscopy-detectable metabolic imaging biomarkers of TERT in low-grade oligodendrogliomas. Unbiased metabolomic analysis of immortalized normal human astrocytes without (NHAcontrol) and with TERT (NHAtert) indicated that TERT induced unique metabolic reprogramming. Notably, TERT increased NADPH and NADH levels. Glucose flux through the pentose phosphate pathway (PPP) is a major producer of NADPH. Non-invasive imaging of PPP flux using hyperpolarized [U-13C,U-2H]-glucose indicated that production of the PPP metabolite 6-phosphogluconate (6-PG) was elevated in NHAtert cells relative to NHAcontrol. Importantly, hyperpolarized [U-13C,U-2H]-glucose flux to 6-PG clearly differentiated tumor from normal brain in orthotopic NHAtert tumor xenografts. Next, we exploited the observation that TERT expression increased NADH, which is essential for the metabolism of hyperpolarized [1-13C]-alanine to lactate. Lactate production from hyperpolarized [1-13C]-alanine was higher in NHAtert cells relative to NHAcontrol. Importantly, hyperpolarized [1-13C]-alanine imaging in orthotopic NHAtert tumors revealed pronounced differences in lactate production between tumor tissue and normal brain. Mechanistically, TERT increased expression of glucose-6-phosphate dehydrogenase (G6PDH), the rate-limiting enzyme for 6-PG and NADPH production, and of nicotinamide phosphoribosyltransferase (NAMPT), a rate-limiting enzyme for NADH biosynthesis. Silencing TERT reversed G6PDH and NAMPT expression and normalized hyperpolarized [U-13C,U-2H]-glucose and [1-13C]-alanine metabolism, validating our imaging biomarkers. Finally, hyperpolarized [U-13C,U-2H]-glucose and [1-13C]-alanine could monitor TERT status in the clinically relevant, patient-derived BT54 oligodendroglioma model. In summary, we demonstrate, for the first time, non-invasive in vivo imaging of TERT status in gliomas that can enable longitudinal analysis of tumor burden and treatment response in the clinic.

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NIMG-51. DEUTERIUM METABOLIC IMAGING OF BRAIN TUMOR IMMORTALITY USING 2H-PYRUVATE

Neuro-Oncology ◽

10.1093/neuonc/noab196.549 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi140-vi141

Author(s):

Georgios Batsios ◽

Céline Taglang ◽

Meryssa Tran ◽

Anne Marie Gillespie ◽

Sabrina Ronen ◽

...

Keyword(s):

Brain Tumor ◽

Lactate Production ◽

Response To Therapy ◽

Telomere Maintenance ◽

Metabolic Imaging ◽

Resonance Spectroscopy ◽

Low Grade ◽

Tumor Proliferation ◽

Non Invasive ◽

Tert Expression

Abstract Telomere maintenance is essential for tumor immortality and sustained tumor proliferation. Most tumors, including high-grade glioblastomas and low-grade oligodendrogliomas achieve telomere maintenance via reactivation of the expression of telomerase reverse transcriptase (TERT), which is silenced in normal somatic cells. Due to this essential role, TERT is a therapeutic target and TERT inhibitors such as 6-thio-2’-deoxyguanosine are in clinical trials. Non-invasive methods of imaging TERT, therefore, have the potential to provide a readout of tumor proliferation and response to therapy. We previously showed that TERT expression is associated with elevated levels of NADH in gliomas. Since NADH is essential for the conversion of pyruvate to lactate, measuring pyruvate flux to lactate could be useful for imaging TERT expression. In this context, deuterium magnetic resonance spectroscopy (2H-MRS) recently emerged as a novel, clinically translatable method of monitoring metabolic fluxes. The goal of this study was to assess the potential of [U-2H]pyruvate for non-invasive imaging of TERT status in gliomas. Following intravenous injection of [U-2H]pyruvate, lactate production was significantly higher in mice bearing orthotopic oligodendroglioma (SF10417, BT88) or glioblastoma (GBM1, GBM6) tumors relative to tumor-free controls. 2D chemical shift imaging showed localization of lactate production to tumor vs. contralateral normal brain. Importantly, following treatment of mice bearing orthotopic GBM6 or BT88 tumors with the TERT inhibitor 6-thio-2’-deoxyguanosine, lactate production from [U-2H]pyruvate was significantly reduced at early timepoints when alterations in tumor volume could not be detected by anatomical imaging, pointing to the ability of [U-2H]pyruvate to report on pseudoprogression. Collectively, we have, for the first time, demonstrated the utility of [U-2H]pyruvate for metabolic imaging of brain tumor burden and treatment response in vivo. Importantly, since 2H-MRS can be implemented on clinical scanners, our results provide a novel, non-invasive method of integrating information regarding a fundamental tumor hallmark, i.e. TERT, into glioma patient management.

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BIMG-02. IMAGING IMMORTALITY: TERT EXPRESSION ALTERS GLUCOSE METABOLISM IN LOW-GRADE GLIOMAS IN A MANNER THAT CAN BE LEVERAGED FOR NONINVASIVE METABOLIC IMAGING

Neuro-Oncology Advances ◽

10.1093/noajnl/vdab024.001 ◽

2021 ◽

Vol 3 (Supplement_1) ◽

pp. i1-i1

Author(s):

Pavithra Viswanath ◽

Georgios Batsios ◽

Anne Marie Gillespie ◽

Hema Artee Luchman ◽

Joseph Costello ◽

...

Keyword(s):

Glucose Metabolism ◽

Response To Therapy ◽

Metabolic Imaging ◽

Additional Patient ◽

Low Grade ◽

Normal Brain ◽

G6pdh Activity ◽

Glucose Flux ◽

13C Mrs ◽

Tert Expression

Abstract Telomerase reverse transcriptase (TERT) is essential for tumor immortality and uncontrolled proliferation, including in low-grade oligodendrogliomas (LGOGs). Since it is silenced in somatic cells, TERT is also a therapeutic target. Non-invasive imaging of TERT can differentiate tumor from normal brain or lesions such as gliosis and allow assessment of response to therapy. The goal of this study was to identify magnetic resonance spectroscopy (MRS)-detectable metabolic alterations associated with TERT that can be leveraged for noninvasive imaging in LGOGs. We examined patient-derived BT54 neurospheres in which TERT expression was silenced by RNA interference. 1H-MRS showed that steady-state levels of NAD(P)/H, glutathione, aspartate and AXP were elevated in BT54TERT+ neurospheres relative to BT54TERT-. Glucose flux through the pentose phosphate pathway (PPP) is essential for generating NADPH, which maintains glutathione homeostasis. 13C-MRS confirmed that [2-13C]-glucose flux through the PPP was elevated in BT54TERT+ neurospheres relative to BT54TERT-, an effect associated with higher activity of the PPP enzyme glucose-6-phosphate dehydrogenase (G6PDH). Hyperpolarized 13C-MRS is a method of increasing the signal to noise ratio of 13C-MRS such that it can monitor metabolic fluxes noninvasively in cells, animals and patients. Consistent with elevated PPP flux and G6PDH activity, hyperpolarized [U-13C]-glucose metabolism via the PPP to 6-phosphogluconate (6-PG) was elevated in BT54TERT+ neurospheres relative to BT54TERT-. Importantly, examination of an additional patient-derived LGOG model, the SF10417 model which readily forms orthotopic tumor xenografts in rats, showed that 6-PG production from hyperpolarized [U-13C]-glucose demarcated tumor from normal brain. Furthermore, LGOG patient biopsies had elevated NAD(P)/H, glutathione, aspartate, AXP and G6PDH activity relative to gliosis biopsies, confirming the clinical validity of our observations. Collectively, we have identified a metabolic signature of TERT expression that can be leveraged via hyperpolarized [U-13C]-glucose to improve diagnosis and treatment response monitoring for LGOG patients.

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Early Noninvasive Metabolic Biomarkers of Mutant IDH Inhibition in Glioma

Metabolites ◽

10.3390/metabo11020109 ◽

2021 ◽

Vol 11 (2) ◽

pp. 109

Author(s):

Marina Radoul ◽

Donghyun Hong ◽

Anne Marie Gillespie ◽

Chloé Najac ◽

Pavithra Viswanath ◽

...

Keyword(s):

Magnetic Resonance ◽

Genetically Engineered ◽

Response To Treatment ◽

Driver Mutations ◽

Resonance Spectroscopy ◽

Low Grade ◽

Isocitrate Dehydrogenase 1 ◽

1H Mrs ◽

Metabolic Biomarkers

Approximately 80% of low-grade glioma (LGGs) harbor mutant isocitrate dehydrogenase 1/2 (IDH1/2) driver mutations leading to accumulation of the oncometabolite 2-hydroxyglutarate (2-HG). Thus, inhibition of mutant IDH is considered a potential therapeutic target. Several mutant IDH inhibitors are currently in clinical trials, including AG-881 and BAY-1436032. However, to date, early detection of response remains a challenge. In this study we used high resolution 1H magnetic resonance spectroscopy (1H-MRS) to identify early noninvasive MR (Magnetic Resonance)-detectable metabolic biomarkers of response to mutant IDH inhibition. In vivo 1H-MRS was performed on mice orthotopically-implanted with either genetically engineered (U87IDHmut) or patient-derived (BT257 and SF10417) mutant IDH1 cells. Treatment with either AG-881 or BAY-1436032 induced a significant reduction in 2-HG. Moreover, both inhibitors led to a significant early and sustained increase in glutamate and the sum of glutamate and glutamine (GLX) in all three models. A transient early increase in N-acetylaspartate (NAA) was also observed. Importantly, all models demonstrated enhanced animal survival following both treatments and the metabolic alterations were observed prior to any detectable differences in tumor volume between control and treated tumors. Our study therefore identifies potential translatable early metabolic biomarkers of drug delivery, mutant IDH inhibition and glioma response to treatment with emerging clinically relevant therapies.

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Reliability of imaging biomarkers for response assessment in advanced lung cancer: Influence of expertise and automation.

Journal of Clinical Oncology ◽

10.1200/jco.2012.30.15_suppl.e13547 ◽

2012 ◽

Vol 30 (15_suppl) ◽

pp. e13547-e13547

Author(s):

Hubert Beaumont ◽

Estanislao Oubel ◽

Antoine Iannessi ◽

Dag Wormanns

Keyword(s):

Lung Cancer ◽

Response Assessment ◽

Response To Therapy ◽

Measuring System ◽

Response To Treatment ◽

Advanced Lung Cancer ◽

Imaging Biomarkers ◽

Axial Diameter ◽

Manual Adjustment ◽

The Impact

e13547 Background: Image-based biomarkers play an important role in the assessment of the response to therapy. The value of imaging biomarkers relies on their reproducibility, which depends on the reviewer and on the measuring system. This study aims at evaluating the impact of readers’ expertise and automation of measurements. Methods: A retrospective study was performed on 10 patients with at least one Non-Small Cell Lung Cancer (NSCLC) lesion, and followed over time (7 time points in average) with Computed Tomography (CT). 2 expert radiologists (ERs) and 5 imaging scientists (ISs) measured the Longest Axial Diameter (LAD) and the volume (VOL) of each lesion at each time point. ERs and ISs segmented the lesions by using a proprietary software providing semi-automatic segmentation processing with manual adjustment. ISs performed an additional session using manual segmentation tools only. From each segmentation, VOL and LAD were automatically computed. The variability of the measurements was calculated by using standard statistics. The response to treatment was assessed according to RECIST thresholds for LAD and with +/-30% thresholds for volume. The inter-reader agreement was measured trough the Kappa coefficient. Finally, the reviewing time with and without automation was analyzed. Results: The use of automated tools by ISs reduced the standard deviation of LAD difference from 10.7% to 8.4%. The inter-reader agreement improved Kappa from 0.57 to 0.68 for LAD, and from 0.52 to 0.69 for VOL. The automation reduced the reviewing time by a factor 4 with respect to the manual assessment. No significant differences in variability were found between ISs and the first ER, but significant differences were observed with respect to the second ER. Conclusions: In a RECIST context, automation improved significantly inter-reader agreement. When using volume as a biomarker, automation not only improved the inter-reader agreement, but also decreased notably the reviewing time. No evidence was found about the influence of the expertise on the volume measurement. The difference in the lesions interpretation by the experts is a relevant factor to account for.

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Arterial spin-labelling and magnetic resonance spectroscopy as imaging biomarkers for detection of epileptogenic zone in non-lesional focal impaired awareness epilepsy

Egyptian Journal of Radiology and Nuclear Medicine ◽

10.1186/s43055-020-00326-8 ◽

2020 ◽

Vol 51 (1) ◽

Author(s):

Rania Essam-el-dein Mohamed ◽

Ashraf Ali Aboelsafa ◽

Rasha Mahmoud Dawoud

Keyword(s):

Magnetic Resonance ◽

Magnetic Resonance Spectroscopy ◽

Imaging Biomarkers ◽

Epileptic Focus ◽

Resonance Spectroscopy ◽

Epileptogenic Zone ◽

1H Mrs ◽

Combined Use ◽

Impaired Awareness

Abstract Background The proper identification of an epileptic focus is a pivotal diagnostic issue; particularly in non-lesional focal impaired awareness epilepsy (FIAE). Seizures are usually accompanied by alterations of regional cerebral blood flow (rCBF) and metabolism. Arterial spin labeling-MRI (ASL-MRI) and proton magnetic resonance spectroscopy (1H-MRS) are MRI techniques that can, non-invasively, define the regions of cerebral perfusion and metabolic changes, respectively. The aim of the current study was to recognize the epileptogenic zone in patients with non-lesional FIAE by evaluating the interictal changes in rCBF and cerebral metabolic alterations, using PASL-MRI and 1H-MRS. Results For identification of the epileptogenic zone, increased ASLAI% assessed by PASL-MRI (at a cut-off value ≥ 5.96%) showed 95.78% accuracy, and increased %AF (at a cut-off value ≥ 9.98%) showed 98.14% accuracy, while decreased NAA/(Cho + Cr) ratio estimated by multi-voxels (MV) 1H-MRS (at a cut-off value ≥ 0.59) showed 97.74% accuracy. Moreover, the combined use of PASL-MRI and MV 1H-MRS yielded 100% sensitivity, 98.45% specificity and 98.86% accuracy. Conclusion The combined use of PASL-MRI and MV 1H-MRS can be considered as in-vivo proficient bio-marker for proper identification of epileptogenic zone in patients with non-lesional FIAE.

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