Naoki Ohno MS, Presenter: Nothing to Disclose

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

Mitsuhito Mase MD, Abstract Co-Author: Nothing to Disclose

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

Harumasa Kasai MSc, Abstract Co-Author: Nothing to Disclose

Shinnosuke Hiratsuka, Abstract Co-Author: Nothing to Disclose

Makoto Kawano, Abstract Co-Author: Nothing to Disclose

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

Toshifumi Gabata MD, Abstract Co-Author: Nothing to Disclose

Osamu Matsui MD, Abstract Co-Author: Nothing to Disclose

We have reported that temporal changes in the brain parenchyma’s apparent diffusion coefficient (ADC) during the cardiac cycle (ΔADC) reveal the degree of fluctuation of water molecules likely resulting from arterial inflow (volume loading) during systole, and this information potentially facilitates the diagnosis of idiopathic normal pressure hydrocephalus (iNPH). However, we assessed the ADC change only in white matter. Moreover, several studies have shown that analysis of intraventricular CSF flow can provide the intracranial condition in iNPH. We therefore determined the temporal change in ADC over the cardiac cycle in the ventricular system of iNPH.

On a 1.5-T MRI, ECG-triggered single-shot diffusion echo planar imaging (b = 0 and 1000 s/mm2) was used with sensitivity encoding and half-scan techniques to minimize the bulk motion. Then ADC image of each cardiac phase were made. Next, a normalized-ΔADC image was calculated from all cardiac phase ADC images (20 phases) on a pixel-by-pixel basis using the following equation: Normalized-ΔADC = (ADCmax - ADCmin)/(ADCmax + ADCmin), where ADCmax and ADCmin represent the maximum and minimum ADC during the cardiac cycle, respectively. We assessed normalized-ΔADC and ADC values in the three ventricular regions, i.e. the anterior and posterior horns of the lateral ventricles and the third ventricle, and compared those values among the iNPH (n=14), atrophic ventricular dilatation (atrophic VD group; n=9), and healthy volunteers (control group; n=8).  

Normalized-ΔADC of the third ventricle was significantly higher in iNPH compared with the control and atrophic VD groups, whereas there were no significant differences for normalized-ΔADC in the other regions among the groups. This result can be explained by the fact that large compression on the ventricular system increases the fluctuation of the water molecules. However, there were no significant differences in ADC of all ventricular regions among the groups.

Normalized-ΔADC analysis as a fluctuation MRI in the ventricular system makes it possible to noninvasively obtain more detailed information on the intracranial condition in iNPH and thereby possibly assist in the diagnosis.

Fluctuation analysis of the intraventricular CSF makes it possible to noninvasively obtain more detailed information on the intracranial condition in iNPH and thereby possibly assist in the diagnosis.

Ohno, N, Miyati, T, Mase, M, Alperin, N, Kasai, H, Hiratsuka, S, Kawano, M, Shibamoto, Y, Gabata, T, Matsui, O, Cerebrospinal Fluid Fluctuation in the Ventricular System in Idiopathic Normal Pressure Hydrocephalus.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13012938.html