Quantification of Nonenhancing Tumor Burden in Gliomas Using Effective T2 Maps Derived from Dual-Echo Turbo Spin-Echo MRI

Ellingson, Benjamin M.; Lai, Albert; Nguyen, Huytram N.; Nghiemphu, Phioanh L.; Pope, Whitney B.; Cloughesy, Timothy F.

doi:10.1158/1078-0432.ccr-14-2862

Cited by 30 publications

(26 citation statements)

References 38 publications

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“…Recently, there has been renewed interest in evaluating role of relaxometry in the assessment of non-enhancing tumor burden and response to anti-angiogenic drug therapy 52–55 . Although most of these recent studies focus on role of T 2 relaxometry, a recent study has demonstrated that T 1 mapping may play a significant role in earlier detection of recurrent tumor in patients on anti-angiogenic therapy.…”

Section: Discussionmentioning

confidence: 99%

MR Fingerprinting of Adult Brain Tumors: Initial Experience

Badve

Yu²,

Dastmalchian

et al. 2016

AJNR Am J Neuroradiol

150

166

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Background Magnetic resonance fingerprinting (MRF) allows rapid simultaneous quantification of T1 and T2 relaxation times. This study assesses the utility of MRF in differentiating between common types of adult intra-axial brain tumors. Methods MRF acquisition was performed in 31 patients with untreated intra-axial brain tumors: 17 glioblastomas, 6 WHO grade II lower-grade gliomas and 8 metastases. T1, T2 of the solid tumor (ST), immediate peritumoral white matter (PW), and contralateral white matter (CW) were summarized within each region of interest. Statistical comparisons on mean, standard deviation, skewness and kurtosis were performed using univariate Wilcoxon rank sum test across various tumor types. Bonferroni correction was used to correct for multiple comparisons testing. Multivariable logistic regression analysis was performed for discrimination between glioblastomas and metastases and area under the receiver operator curve (AUC) was calculated. Results Mean T2 values could differentiate solid tumor regions of lower-grade gliomas from metastases (mean±sd: 172±53ms and 105±27ms respectively, p =0.004, significant after Bonferroni correction). Mean T1 of PW surrounding lower-grade gliomas differed from PW around glioblastomas (mean±sd: 1066±218ms and 1578±331ms respectively, p=0.004, significant after Bonferroni correction). Logistic regression analysis revealed that mean T2 of ST offered best separation between glioblastomas and metastases with AUC of 0.86 (95% CI 0.69–1.00, p<0.0001). Conclusion MRF allows rapid simultaneous T1, T2 measurement in brain tumors and surrounding tissues. MRF based relaxometry can identify quantitative differences between solid-tumor regions of lower grade gliomas and metastases and between peritumoral regions of glioblastomas and lower grade gliomas.

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Section: Discussionmentioning

confidence: 99%

MR Fingerprinting of Adult Brain Tumors: Initial Experience

Badve

Yu²,

Dastmalchian

et al. 2016

AJNR Am J Neuroradiol

150

166

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“…The total scan time for CEST‐EPI was approximately 5 min. Since many of the low‐grade gliomas and anaplastic tumors contained significant non‐enhancing disease, values of MTR asym within T 2 ‐hyperintense lesions representative of non‐enhancing tumor were evaluated for these patients and compared across tumor grade.…”

Section: Methodsmentioning

confidence: 99%

Simulation, phantom validation, and clinical evaluation of fast pH‐weighted molecular imaging using amine chemical exchange saturation transfer echo planar imaging (CEST‐EPI) in glioma at 3 T

et al. 2016

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Acidity within the extracellular milieu is a hallmark of cancer. There is a current need for fast, high spatial resolution pH imaging techniques for clinical evaluation of cancers, including gliomas. Chemical exchange saturation transfer (CEST) MRI targeting fast-exchanging amine protons can be used to obtain high-resolution pH-weighted images, but conventional CEST acquisition strategies are slow. There is also a need for more accurate MR simulations to better understand the effects of amine CEST pulse sequence parameters on pH-weighted image contrast. In the current study we present a simulation of amine CEST contrast specific for a newly developed CEST echoplanar imaging (EPI) pulse sequence. The accuracy of the simulations was validated by comparing the exchange rates and Z-spectrum under a variety of conditions using physical phantoms of glutamine with different pH values. The effects of saturation pulse shapes, pulse durations, pulse train lengths, repetition times, and relaxation rates of bulk water and exchangeable amine protons on the CEST signal were explored for normal-appearing white matter (NAWM), glioma, and cerebrospinal fluid. Last, 18 patients with WHO II-IV gliomas were evaluated. Results showed that the Z-spectrum was highly dependent on saturation pulse shape, repetition time, saturation amplitude, magnetic field strength, and T within bulk water; however, the Z-spectrum was only minimally influenced by saturation pulse duration and the specific relaxation rates of amine protons. Results suggest that a Gaussian saturation pulse train consisting of 3 × 100 ms pulses using the minimum allowable repetition time is optimal for achieving over 90% available contrast across all tissues. Results also demonstrate that high saturation pulse amplitude and scanner field strength (>3 T) are necessary for adequate endogenous pH-weighted amine CEST contrast. pH-weighted amine CEST contrast increased with increasing tumor grade, with glioblastoma showing significantly higher contrast compared with WHO II or III gliomas.

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“…In our study we applied histogram matching to facilitate comparison of MR images between patients. In a multi-institutional setting, more sophisticated preprocessing techniques may be used to minimize the effects of different imaging acquisition protocols (38). …”

Section: Discussionmentioning

confidence: 99%

Robust Estimation of Electron Density From Anatomic Magnetic Resonance Imaging of the Brain Using a Unifying Multi-Atlas Approach

Ren

Hara

Wang

et al. 2017

International Journal of Radiation Oncology*Biology*Physics

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Purpose To develop a reliable method to estimate electron density based on anatomic magnetic resonance imaging (MRI) of the brain. Methods and Materials We proposed a unifying multi-atlas approach for electron density estimation based on standard T1- and T2-weighted MRI. First, a composite atlas was constructed through a voxelwise matching process using multiple atlases, with the goal of mitigating effects of inherent anatomic variations between patients. Next we computed for each voxel 2 kinds of conditional probabilities: (1) electron density given its image intensity on T1- and T2-weighted MR images; and (2) electron density given its spatial location in a reference anatomy, obtained by deformable image registration. These were combined into a unifying posterior probability density function using the Bayesian formalism, which provided the optimal estimates for electron density. We evaluated the method on 10 patients using leave-one-patient-out cross-validation. Receiver operating characteristic analyses for detecting different tissue types were performed. Results The proposed method significantly reduced the errors in electron density estimation, with a mean absolute Hounsfield unit error of 119, compared with 140 and 144 (P<.0001) using conventional T1-weighted intensity and geometry-based approaches, respectively. For detection of bony anatomy, the proposed method achieved an 89% area under the curve, 86% sensitivity, 88% specificity, and 90% accuracy, which improved upon intensity and geometry-based approaches (area under the curve: 79% and 80%, respectively). Conclusion The proposed multi-atlas approach provides robust electron density estimation and bone detection based on anatomic MRI. If validated on a larger population, our work could enable the use of MRI as a primary modality for radiation treatment planning.

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Quantification of Nonenhancing Tumor Burden in Gliomas Using Effective T2 Maps Derived from Dual-Echo Turbo Spin-Echo MRI

Cited by 30 publications

References 38 publications

MR Fingerprinting of Adult Brain Tumors: Initial Experience

MR Fingerprinting of Adult Brain Tumors: Initial Experience

Simulation, phantom validation, and clinical evaluation of fast pH‐weighted molecular imaging using amine chemical exchange saturation transfer echo planar imaging (CEST‐EPI) in glioma at 3 T

Robust Estimation of Electron Density From Anatomic Magnetic Resonance Imaging of the Brain Using a Unifying Multi-Atlas Approach

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