Magnetic resonance in medicine : official journal of the Society of Magnetic Resonance in Medicine
-
To separately measure N-acetyl aspartul glutamate (NAAG), N-acetyl aspartate (NAA), aspartate (Asp), and glutamate (Glu) concentrations in white matter (WM) using J-editing techniques in patients with mild traumatic brain injury (mTBI) in the acute phase. ⋯ The main finding of the study is that the tNAA signal reduction in WM after mTBI is associated with a decrease in the NAAG concentration rather than a decrease in the NAA concentration, as was thought previously. This finding highlights the importance of separating these signals, at least for WM studies, to avoid misinterpretation of the results. NAAG plays an important role in selectively activating mGluR3 receptors, thus providing neuroprotective and neuroreparative functions immediately after mTBI. NAAG shows potential for the development of new therapeutic strategies for patients with injuries of varying severity.
-
To use hyperoxia in combination with QSM to quantify microvascular oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2 ) in healthy subjects and to cross-validate results with those from hypercapnia QSM-OEF. ⋯ Hyperoxia in combination with QSM is a robust approach to measure OEF. Compared with hypercapnia, hyperoxia is more comfortable and has minimal impact on cerebral blood flow.
-
In MRI, the macromolecular proton fraction (MPF) is a key parameter of magnetization transfer (MT). It represents the relative amount of immobile protons associated with semi-solid macromolecules involved in MT with free water protons. We aim to quantify MPF based on spin-lock MRI and explore its advantages over the existing MPF-mapping methods. ⋯ A novel MPF imaging method based on spin-lock MRI is proposed. The confounding factors are removed, and the measurement is specific to the MT effect. It holds promise for MPF-sensitive diagnostic imaging in clinical settings.
-
To develop a free-breathing isotropic-resolution whole-heart joint T1 and T2 mapping sequence with Dixon-encoding that provides coregistered 3D T1 and T2 maps and complementary 3D anatomical water and fat images in a single ~9 min scan. ⋯ The proposed joint T1 /T2 sequence permitted the acquisition of motion-compensated isotropic-resolution 3D T1 and T2 maps and complementary coronary MR angiography and fat volumes, showing promising results in terms of T1 and T2 quantification and visualization of cardiac anatomy and pericardial fat.