Objective: To investigate intracranial cerebrospinal fluid (CSF) distribution in patients with a clinical diagnosis of idiopathic normal pressure hydrocephalus (INPH). Methods: 24 patients with a clinical diagnosis of INPH were studied. Control groups comprised 17 patients with secondary normal pressure hydrocephalus (SNPH), 21 patients with brain atrophy, and 18 healthy volunteers. Ventricular volume (VV) and intracranial CSF volume (ICV) were measured using a magnetic resonance based method and the VV/ICV ratio was calculated. Results: The SNPH group showed a marked increase in the VV/ICV ratio compared with the healthy volunteers (37.8% v 15.6%, p < 0.0001). The brain atrophy group showed a significant increase in ICV compared with the healthy volunteers (284.4 ml v 194.7 ml, p =0.0002). The INPH group showed an increase in ICV (281.2 ml, p = 0.0002) and an increase in the VV/ICV ratio (38.0%, p < 0.0001). Fifteen of 24 INPH patients underwent shunting; 11 improved and four did not.
Conclusions:The results suggest that INPH patients have brain atrophy in addition to hydrocephalic features. This may help to explain the difficulties encountered in the diagnosis and the unpredictable response rate to shunt surgery in INPH patients.T he diagnosis and appropriate treatment of patients with cognitive decline, ataxia, and incontinence is not easy, as only a proportion will have idiopathic normal pressure hydrocephalus (INPH), 1-3 and many of these patients may also have early Alzheimer's disease or vascular dementia. Coexistent cerebrovascular disease or Alzheimer's disease is generally a predictor of poor outcome following CSF diversion.
5However, others have reported that despite vascular or Alzheimer changes in biopsy specimens from patients with clinically diagnosed INPH, some are still improved by shunting. 5 6 Indeed, several studies have suggested that vascular changes might play an important role in the pathophysiology of INPH in some patients.
7Secondary normal pressure hydrocephalus (SNPH), which is not uncommon after subarachnoid haemorrhage and other disorders, generally responds well to CSF diversion and may share some neuroradiological features with INPH.1 7 It would be very helpful, therefore, if we could explain the differences between INPH, SNPH, Alzheimer's disease, and vascular dementia in terms of quantitative diagnostic variables. We have reported that, using a magnetic resonance based cerebrospinal fluid (CSF) measurement method, an increase in the intracranial CSF volume is seen in patients with brain atrophy and a disproportionate increase in the ventricular CSF volume is seen in patients with hydrocephalus. 8 9 Our method is non-invasive and relatively easy to perform in elderly or uncooperative patients.Our aim in this study was to investigate intracranial CSF distribution in patients with suspected INPH in comparison with SNPH or brain atrophy.
METHODS
SubjectsWe studied 80 subjects, all of whom gave their informed consent. The INPH group included 24 of 41 patients with suspected INPH (11 ...
Our purpose was to quantify the intracranial cerebrospinal fluid (CSF) volume components using an original MRI-based segmentation technique and to investigate whether a CSF volume index is useful for diagnosis of normal pressure hydrocephalus (NPH). We studied 59 subjects: 16 patients with NPH, 14 young and 13 elderly normal volunteers, and 16 patients with cerebrovascular disease. Images were acquired on a 1.5-T system, using a 3D-fast asymmetrical spin-echo (FASE) method. A region-growing method (RGM) was used to extract the CSF spaces from the FASE images. Ventricular volume (VV) and intracranial CSF volume (ICV) were measured, and a VV/ICV ratio was calculated. Mean VV and VV/ICV ratio were higher in the NPH group than in the other groups, and the differences were statistically significant, whereas the mean ICV value in the NPH group was not significantly increased. Of the 16 patients in the NPH group, 13 had VV/ICV ratios above 30%. In contrast, no subject in the other groups had a VV/ICV ratios higher than 30%. We conclude that these CSF volume parameters, especially the VV/ICV ratio, are useful for the diagnosis of NPH.
The three-dimensional fast spin echo method offers ultrahigh-resolution images, which are extremely useful in understanding the surgical anatomy of the CPA and IAC.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.