OPTIMIZATION OF GRADIENT-ECHO MR FOR CALCIUM DETECTION

PURPOSE: To determine optimal MR gradient-echo sequences for the visua lization of calcium in neurologic MR. METHOD: The dependence of signal intensity and image contrast on the imaging parameters repetition tim e, echo time, flip angle, and spoiling were measured for hydroxyapatit e samples. Calculations of signal intensity were shown to correspond t o these measures. RESULTS: Optimum detectibility was obtained with an echo time of 29 msec and was independent of spoiling. As repetition ti me ranged from 30 msec to 700 msec, the optimal flip angle ranged from 17 degrees to 66 degrees. CONCLUSIONS: Gradient-echo sequences that o ptimize the contrast for detection of calcium in neurologic imaging ha ve been determined.