Noam Alperin PhD, Presenter: Stockholder, Alperin Noninvasive Diagnostics, Inc, Chicago, IL

Sang H. Lee MS, Abstract Co-Author: Nothing to Disclose

William Chiang, Abstract Co-Author: Nothing to Disclose

Roberta Glick MD, Abstract Co-Author: Nothing to Disclose

Normally CSF flows out of the ventricles through foramina into the subarachnoid space. It was recently reported that net aqueductal outflow measured by MRI cine phase contrast is a reliable estimate of supratentorial CSF production rate. In this work, net aqueductal flow was measured in patients with communicating hydrocephalus, in patients with Chiari malformation and in healthy control group. The purpose is to test the hypothesis that net inflow (e.g., negative outflow) occurs only in hydrocephalic patients. We further expect that T2 weighted MRI FLAIR images of these patients would demonstrate hyperintensities in the periventrricular regions due to increase interstitial water content.

Net aqueductal flow was measured in five healthy subjects, ten patients with Chiari malformations, and ten patients with communicating hydrocephalous of various causes. In two subjects scans were repeated four times to determine measurement variability. None of the patients had ventricular shunt. CSF aqueductal volumetric flow was measured by cine phase contract with velocity encoding of 10-20 cm/sec, retrospective gating and data reconstructed into 32 phases. Automated segmentation of the aqueductal lumen area was obtained with software utilizing the pulsatility based segmentation technique (Alperin Noninvasive Diagnostics, Chicago, IL). In addition, T2 weighted FLAIR Images were obtained to assess the presence of hyperintensities in the periventricular regions.

Measurement variability was about 12%. All healthy subjects and Chiari patients had positive net CSF outflow (0.41 ± 0.25 and 0.52 ± 0.35 mL/min, respectively). Three of the hydrocephalic patients (NPH patients and a patient who underwent radiation for pineal tumor) had negative net outflow ranging from -1.3 to -0.38 mL/min. FLAIR images of these patients demonstrated large regions of hypeintensities.

Net CSF aqueductal inflow suggest ventricular-to-parenchyma transependymal CSF bulk flow. Ventricular CSF potentially contributed to elevated periventricular water content.

Measurements of net aqueductal flow may have an important role in understanding the pathophysiology of NPH and may help identify shunt responders

Alperin, N, Lee, S, Chiang, W, Glick, R, MRI Measurements of Net Aqueductal CSF Flow Provide Evidence for Transependymal Bulk Flow in Communicating Hydrocephalus.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5004395.html