Thirty subjects with [[idiopathic normal pressure hydrocephalus]] (iNPH) underwent both [[CBF]] [[SPECT]] and MRI. After normalization, voxel-wise two-sample t tests between patients and 11 normal controls were conducted to compare the regional alteration in the gray matter density and [[regional cerebral blood flow]] (rCBF).

The rCBF reduction and the gray matter decrease were seen in almost similar regions surrounding [[Sylvian fissure]], the left parietotemporal region and [[frontal lobe]]s, whereas they did not find rCBF increase at the top of the high convexity, where the increase of the [[gray matter]] density was the highest (p < 0.05).

This study showed regional associations and dissociations between the relative gray matter density and rCBF in patients with iNPH
((Takahashi R, Ishii K, Tokuda T, Nakajima M, Okada T; SINPHONI-2 Investigators.
Regional dissociation between the cerebral blood flow and gray matter density
alterations in idiopathic normal pressure hydrocephalous: results from SINPHONI-2
study. Neuroradiology. 2018 Sep 30. doi: 10.1007/s00234-018-2106-1. [Epub ahead
of print] PubMed PMID: 30269153.
)).