Tomohiro Chigusa, Presenter: Nothing to Disclose

Tosiaki Miyati PhD, Abstract Co-Author: Nothing to Disclose

Hirohito Kan, Abstract Co-Author: Nothing to Disclose

Masaki Hara MD, PhD, Abstract Co-Author: Nothing to Disclose

Yuta Shibamoto MD, PhD, Abstract Co-Author: Nothing to Disclose

Noam Alperin PhD, Abstract Co-Author: Stockholder, Alperin Noninvasive Diagnostics, Inc

Harumasa Kasai, Abstract Co-Author: Nothing to Disclose

Nobuyuki Arai MS, Abstract Co-Author: Nothing to Disclose

Akihiro Kitanaka, Abstract Co-Author: Nothing to Disclose

Risa Yorimitsu, Abstract Co-Author: Nothing to Disclose

Makoto Kawano, Abstract Co-Author: Nothing to Disclose

We reported that the apparent diffusion coefficient (ADC) in cerebral white matter significantly changed during the cardiac cycle, due to the arterial-blood volume loading of the cranium even though minimizing the bulk motion effect. To clarify the mechanism, i.e., the fluctuation of the water molecules in the intracranial tissue, we determined the temporal ADC waves obtained with diffusion magnetic resonance imaging (MRI) using a hemodialyzer phantom.

The hemodialyzer phantom consisted of capillary vessels, extravascular space, and intracranial capacitor components, which were filled with syrup solution (ADC=0.6 mm2/s) and air. These correspond to a blood capillary, brain tissues, and brain capacity, respectively. Then, the volume loading was periodically applied to the capillary vessels of the phantom by a to-and-fro flow pump for simulating the fluctuation of water molecules of the brain. On a 1.5-T MRI, diffusion weighted images (DWI) were obtained in synchronization with the volume-loading using ECG-triggered single-shot diffusion EPI with sensitivity encoding and half-scan techniques to minimize the data sampling window. ADC maps in a direction perpendicular to the capillary vessels, i.e., x-y plane, were calculated from the DWIs at each volume loading phase.

The peak ADC in the x-y plane corresponded with the maximum slope of the internal pressure. Changes in the ADC in x-y plane and internal pressure in extravascular space in high- volume loading were larger than those in low-volume loading. However, the ADC-change/volume-loading and the compliances (volume-change/pressure-change) in the phantom were almost the same between high-and low-volume loadings. These results show that the water molecules in extravascular space were fluctuated by the volume loading in capillary vessels, i.e., the ADC change depends on the volumetric change per unit time. This relation provides the biomechanical information of the phantom, i.e., intracranial tissue.

Our original phantom makes it possible to analyze the change in ADC due to the volume loading, assess the biomechanical property, and verify the mechanism of the fluctuation of water molecules in the intracranial tissue.

Our original phantom makes it possible to verify the mechanism of the fluctuation of water molecules in the intracranial tissue.

Chigusa, T, Miyati, T, Kan, H, Hara, M, Shibamoto, Y, Alperin, N, Kasai, H, Arai, N, Kitanaka, A, Yorimitsu, R, Kawano, M, Regional Biomechanical Property of Intracranial Tissue Using Dynamic Diffusion MRI: A Phantom Study.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11034365.html Accessed October 23, 2025