A5078041599- Advanced MRI Techniques and Applications
- Lanthanide and Transition Metal Complexes
- MRI in cancer diagnosis
- Electron Spin Resonance Studies
- Medical Imaging Techniques and Applications
- Advanced Neuroimaging Techniques and Applications
- Glioma Diagnosis and Treatment
- Radiomics and Machine Learning in Medical Imaging
- Advanced X-ray Imaging Techniques
- Functional Brain Connectivity Studies
- Atomic and Subatomic Physics Research
- Advanced NMR Techniques and Applications
- Traumatic Brain Injury and Neurovascular Disturbances
- Molecular Biology Techniques and Applications
- Nuclear Physics and Applications
- Cancer, Hypoxia, and Metabolism
- Advancements in Photolithography Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Epigenetics and DNA Methylation
- Advanced Fiber Optic Sensors
- Advanced Electron Microscopy Techniques and Applications
- Polymer crystallization and properties
- Intracerebral and Subarachnoid Hemorrhage Research
- Metabolomics and Mass Spectrometry Studies
- Photonic and Optical Devices
Kennedy Krieger Institute
2016-2025
Johns Hopkins University
2016-2025
Athinoula A. Martinos Center for Biomedical Imaging
2024
Massachusetts General Hospital
2024
Tel Aviv University
2024
Memorial Sloan Kettering Cancer Center
2024
Harvard University
2024
Johns Hopkins Medicine
2015-2023
University of Ulsan
2020
Asan Medical Center
2020
Purpose To assess amide proton transfer‐weighted (APTW) imaging features in patients with malignant gliomas after chemoradiation and the diagnostic performance of APT for distinguishing true progression from pseudoprogression. Materials Methods After approval by Institutional Review Board, 32 clinically suspected tumor first 3 months were enrolled scanned at 3T. Longitudinal routine magnetic resonance (MRI) changes medical records assessed to confirm versus True was defined as lesions...
Localized pH changes have been suggested to occur in the brain during normal function. However, existence of such has also questioned. Lack methods for noninvasively measuring with high spatial and temporal resolution limited insight into this issue. Here we report that a magnetic resonance imaging (MRI) strategy, T 1 relaxation rotating frame (T ρ), is sufficiently sensitive detect widespread mouse human evoked by systemically manipulating carbon dioxide or bicarbonate. Moreover, ρ detected...
Purpose To assess the amide proton transfer‐weighted (APTw) MRI features of isocitrate dehydrogenase (IDH)‐wildtype and IDH‐mutant grade II gliomas to test hypothesis that APTw signal is a surrogate imaging marker for identifying IDH mutation status preoperatively. Methods Twenty‐seven patients with pathologically confirmed low‐grade glioma, who were previously scanned at 3T, retrospectively analyzed. The Mann‐Whitney was used evaluate relationships between intensities IDH‐wildtype groups,...
Abstract Purpose: To quantify the accuracy of amide proton transfer-weighted (APTw) MRI for identifying active glioma after treatment via radiographically guided stereotactic tissue validation. Experimental Design: Twenty-one patients who were referred surgery features concerning tumor progression versus effect underwent preoperative APTw imaging. Stereotactic biopsy samples taken from regions interest with varying signal intensities. The relationship between final clinical pathology and...
Purpose To quantify amide proton transfer (APT) and nuclear Overhauser enhancement (NOE) contributions to in vivo chemical exchange saturation MRI signals tumors. Theory Methods Two‐pool (free water semi‐solid protons) four‐pool water, semi‐solid, amide, upfield NOE‐related tissue models combined with the super‐Lorentzian lineshape for protons were used fit wide narrow frequency‐offset magnetization‐transfer (MT) data, respectively. Extrapolated MT at 3.5 −3.5 ppm from as reference APT NOE,...
Purpose To evaluate the use of three extrapolated semisolid magnetization transfer reference (EMR) methods to quantify amide proton (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 fit two‐sided, wide‐offset data), sEMR (symmetric 1 one‐sided, data) assessed. Z EMR experimental data 3.5 ppm −3.5 subtracted calculate APT NOE (APT # ),...
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 IV) at 7T.APT-based NOE-based signals 7T using low-power steady-state chemical exchange saturation (CEST) were compared among de novo primary gliomas WHO IV). The quantitative APT NOE signals, calculated by fitting approach extrapolated semisolid MT reference (EMR) magnetization ratio asymmetry...
Purpose To quantify amide protein transfer (APT) effects in acidic ischemic lesions and assess the spatial‐temporal relationship among diffusion, perfusion, pH deficits acute stroke patients. Methods Thirty patients were scanned at 3 T. Quantitative APT (APT # ) measured using an extrapolated semisolid magnetization reference signal technique compared with commonly used MTR asym (3.5ppm) or APT‐weighted parameters. Results The images showed clear lesion, whereas signals slightly hypointense....
Purpose To evaluate the reliability of four CEST imaging metrics for brain tumors, at varied saturation power levels and magnetic field strengths (3−9.4 Tesla (T)). Methods A five‐pool proton exchange model (free water, semisolid, amide, amine, NOE‐related protons) was used simulations. For in vivo study, eight glioma‐bearing rats were scanned 4.7 T. The ratio (CESTR), CESTR normalized with reference value (CESTR nr ), inverse Z‐spectrum‐based (MTR Rex apparent exchange‐related relaxation...
Purpose To explore the capability of amide proton transfer (APT) imaging in detection hemorrhagic and ischemic strokes using preclinical rat models. Methods The intracerebral hemorrhage (ICH) model (n = 10) was induced by injecting bacterial collagenase VII‐S into caudate nucleus, permanent stroke a 4‐0 nylon suture to occlude origin middle cerebral artery. APT‐weighted (APTw) MRI acquired on 4.7T animal imager quantified magnetization transfer‐ratio asymmetry at 3.5 ppm from water. Results...
Purpose To evaluate the feasibility of accelerated chemical‐exchange‐saturation‐transfer (CEST) imaging using a combination compressed sensing (CS) and sensitivity encoding (SENSE) at 3 Tesla. Theory Methods Two healthy volunteers six high‐grade glioma patients were recruited. Raw CEST image k‐space data acquired (with varied radiofrequency saturation power levels for volunteer study), sequential CS SENSE reconstruction (CS‐SENSE) was assessed. The MTR asym (3.5 ppm) signals compared with...
Purpose To quantify pure chemical exchange–dependent saturation transfer (CEST) related amide proton (APT) and nuclear Overhauser enhancement (NOE) signals in a rat glioma model to investigate the mixed effects of water content T 1 on APT NOE imaging signals. Methods Eleven U87 tumor‐bearing rats were scanned at 4.7 T. A relatively accurate mathematical approach, based extrapolated semisolid magnetization‐transfer reference signals, was used remove concurrent direct magnetization‐transfer....
Background To compare different reference images selected for registration among chemical exchange saturation transfer (CEST) series. Materials and Methods Five normal volunteers eight brain tumor patients were studied on a 3 Tesla scanner. Image was performed by choosing each of the acquired CEST or unsaturation dynamic as reference. at 3.5 ppm (amide proton transfer, APT) computed motion‐corrected data set after main magnetic field inhomogeneity correction. A uniformity index defined to...
Background Amide proton transfer (APT) MRI has the potential to demonstrate antitumor effects by reflecting biologically active tumor portion, providing different information from diffusion-weighted imaging (DWI) or dynamic susceptibility contrast (DSC) imaging. Purpose To evaluate whether a change in APT signal intensity after antiangiogenic treatment is predictive of early response recurrent glioblastoma. Materials and Methods In this retrospective study, MRI, DWI, DSC were performed...
Semisolid magnetization transfer contrast (MTC) and chemical exchange saturation (CEST) MRI based on MT phenomenon have shown potential to evaluate brain development, neurological, psychiatric, neurodegenerative diseases. However, a qualitative ratio (MTR) metric commonly used in conventional MTC imaging is limited the assessment of quantitative semisolid macromolecular proton rates concentrations. In addition, CEST signals measured by MTR asymmetry analysis are unavoidably contaminated...
Purpose To develop a fast, quantitative 3D magnetization transfer contrast (MTC) framework based on an unsupervised learning scheme, which will provide baseline reference signals for CEST and nuclear Overhauser enhancement imaging. Methods Pseudo‐randomized RF saturation parameters relaxation delay times were applied in MR fingerprinting to generate transient‐state signal evolutions different MTC parameters. Prospectively compressed sensing–accelerated (four‐fold) images acquired from 6...