To quantify periodic displacement in the cranium using complementary spatial modulation of magnetization (CSPAMM) with harmonic phase (HARP) postprocessing.
MATERIALS AND METHODS:
CSPAMM tagging sequence with separate tag-line preparation in two orthogonal directions was applied on 10 healthy volunteers in combination with HARP for tissue displacement mapping.
Important features of brain dynamics, such as caudal displacement amplitude and the time-to-peak of the pulse wave were derived for six regions in the brain. Peak displacement values amounted to 0.18+/-0.02 mm, 0.10+/-0.01 mm, 0.09+/-0.02 mm, and 0.04+/-0.01 mm for regions in the pons, cerebellum, corpus callosum (splenium), and frontal lobe, respectively. Displacement values of the pons differed significantly from all other regions measured. With the additional information of the time-to-peak measure all six regions except the corpus callosum (splenium) and cerebellum can be distinguished. The values found suggest that the pulse wave travels from the brain stem first occipitally and then to the frontal lobe, where peak values appear later and are significantly attenuated.
Direct quantification of periodic caudal brain tissue displacement is feasible with the proposed method, and several brain regions can be distinguished through peak displacement and time-to-peak values.