in Vivo 35 cl Mr imaging in humans : A Feasibility Study 1

Materials and Methods: All examinations were performed with ethical review board approval; written informed consent was obtained from all volunteers. Seven examinations each of brain and muscle in healthy volunteers and four examinations of patients were performed. Two patients with histologically confirmed glioblastoma multiforme underwent brain imaging. 35Cl MR and 35Cl inversion-recovery (IR) MR were performed. Two patients with genetically confirmed hypokalemic periodic paralysis underwent calf muscle imaging. Seven multiecho sequences (acquisition time, 5 minutes; voxel dimension, 11 mm3) were applied to determine transverse relaxation time as affected by magnetic field heterogeneity (T2*) and chlorine concentration. 35Cl and sodium 23 (23Na) MR were conducted with a 7-T whole-body MR system. 35Cl longitudinal relaxation time (T1) and T2* of healthy human brain and muscle were determined with a three-dimensional density-adapted– projection reconstruction technique to achieve short echo times and high signal-to-noise ratio (SNR) efficiency. A nonlinear least squares routine and mono(T1) and biexponential (T2*) models were used for curve fitting.