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Localized pH changes have been suggested to occur in the brain during normal function. However, the existence of such pH changes has also been questioned. Lack of methods for noninvasively measuring pH with high spatial and temporal resolution has limited insight into this issue. Here we report that a magnetic resonance imaging (MRI) strategy, T(1)(More)
PURPOSE To quantify amide proton transfer (APT) and nuclear Overhauser enhancement (NOE) contributions to in vivo chemical exchange saturation transfer MRI signals in tumors. THEORY AND METHODS Two-pool (free water and semi-solid protons) and four-pool (free water, semi-solid, amide, and upfield NOE-related protons) tissue models combined with the(More)
PURPOSE To investigate the biochemical origin of the amide photon transfer (APT)-weighted hyperintensity in brain tumors. PROCEDURES Seven 9 L gliosarcoma-bearing rats were imaged at 4.7 T. Tumor and normal brain tissue samples of equal volumes were prepared with a coronal rat brain matrix and a tissue biopsy punch. The total tissue protein and the(More)
PURPOSE To quantify pure chemical exchange-dependent saturation transfer (CEST) related amide proton transfer (APT) and nuclear Overhauser enhancement (NOE) signals in a rat glioma model and to investigate the mixed effects of water content and water T1 on APT and NOE imaging signals. METHODS Eleven U87 tumor-bearing rats were scanned at 4.7 T. A(More)
PURPOSE To evaluate the use of three extrapolated semisolid magnetization transfer reference (EMR) methods to quantify amide proton transfer (APT) and nuclear Overhauser enhancement (NOE) signals in human glioma. METHODS Eleven patients with high-grade glioma were scanned at 3 Tesla. aEMR(2) (asymmetric magnetization-transfer or MT model to fit two-sided,(More)
To show the ability of using the amide proton transfer-weighted (APTW) MRI signals as imaging biomarkers to differentiate primary central nervous system lymphomas (PCNSLs) from high-grade gliomas (HGGs). Eleven patients with lymphomas and 21 patients with HGGs were examined. Magnetization-transfer (MT) spectra over an offset range of ±6 ppm and the(More)
PURPOSE To explore the capability of amide proton transfer (APT) imaging in the detection of hemorrhagic and ischemic strokes using preclinical rat models. METHODS The rat intracerebral hemorrhage (ICH) model (n = 10) was induced by injecting bacterial collagenase VII-S into the caudate nucleus, and the permanent ischemic stroke model (n = 10) was induced(More)
BACKGROUND To compare different reference images selected for registration among chemical exchange saturation transfer (CEST) series. MATERIALS AND METHODS Five normal volunteers and eight brain tumor patients were studied on a 3 Tesla scanner. Image registration was performed by choosing each of the acquired CEST saturation or unsaturation dynamic images(More)
PURPOSE To assess amide proton transfer-weighted (APTW) imaging features in patients with malignant gliomas after chemoradiation and the diagnostic performance of APT imaging for distinguishing true progression from pseudoprogression. MATERIALS AND METHODS After approval by the Institutional Review Board, 32 patients with clinically suspected tumor(More)
PURPOSE To explore the relationship of amide proton transfer (APT) and nuclear Overhauser enhancement (NOE) signal intensities with respect to different World Health Organization (WHO) brain tumor grades (II to IV) at 7T. MATERIALS AND METHODS APT-based and NOE-based signals at 7T using low-power steady-state chemical exchange saturation transfer (CEST)(More)