Differentiating shunt-responsive normal pressure hydrocephalus from Alzheimer disease and normal aging: pilot study using automated MRI brain tissue segmentation

Abstract

Evidence suggests that normal pressure hydrocephalus (NPH) is underdiagnosed in day to day radiologic practice, and differentiating NPH from cerebral atrophy due to other neurodegenerative diseases and normal aging remains a challenge. To better characterize NPH, we test the hypothesis that a prediction model based on automated MRI brain tissue segmentation can help differentiate shunt-responsive NPH patients from cerebral atrophy due to Alzheimer disease (AD) and normal aging. Brain segmentation into gray and white matter (GM, WM), and intracranial cerebrospinal fluid was derived from pre-shunt T1-weighted MRI of 15 shunt-responsive NPH patients (9 men, 72.6 ± 8.0 years-old), 17 AD patients (10 men, 72.1 ± 11.0 years-old) chosen as a representative of cerebral atrophy in this age group; and 18 matched healthy elderly controls (HC, 7 men, 69.7 ± 7.0 years old). A multinomial prediction model was generated based on brain tissue volume distributions. GM decrease of 33% relative to HC characterized AD (P < 0.005). High preoperative ventricular and near normal GM volumes characterized NPH. A multinomial regression model based on gender, GM and ventricular volume had 96.3% accuracy differentiating NPH from AD and HC. In conclusion, automated MRI brain tissue segmentation differentiates shunt-responsive NPH with high accuracy from atrophy due to AD and normal aging. This method may improve diagnosis of NPH and improve our ability to distinguish normal from pathologic aging.

Effect of infusion tests on the dynamical properties of intracranial pressure in hydrocephalus

“…Patients with hydrocephalus generally show clinical symptoms, ventriculomegaly and anomalous cerebrospinal fluid (CSF) dynamics [1,2]. Normal pressure hydrocephalus (NPH) can appear as a primary condition [3] or as a consequence of subarachnoid haemorrhage, traumatic brain injury (TBI) or meningitis [1,3]. Implantation of a CSF shunt is the main treatment option [4].…”

Concurrent Alzheimer’s pathology in patients with clinical normal pressure hydrocephalus: correlation of high-volume lumbar puncture results, cortical brain biopsies, and outcomes

“…However, the identification of patients with NPH most likely to benefit from shunting procedures remains difficult. 8,17,21 Marmarou et al performed a literature review and found that the sensitivity of predicting successful outcomes based on clinical and imaging findings alone can be as low as 46%. The addition of high-volume lumbar puncture (HVLP) yielded a sensitivity of 26%-61%, and CSF outflow resistance studies had sensitivities of 57%-100%.…”

Lumbar Puncture Test in Normal Pressure Hydrocephalus: Does the Volume of CSF Removed Affect the Response to Tap?

“…3 The diagnosis of NPH is characterized by several neuroimaging features, including ventricular dilation in the presence of normal gray matter volume, but despite a very large number of publications since 1964, the role of neuroimaging in predicting the response to shunting remains uncertain. 4,5 Tarnaris et al 6 performed a literature review of 69 studies published between 1980 and 2006 to examine the role of structural as well as functional imaging in providing biomarkers of favorable surgical outcome in NPH. The papers reviewed included studies of structural CT and MR imaging features; 4,6-9 phase-contrast MR imaging studies of aqueductal CSF velocity and stroke volumes; [10][11][12] and functional studies including xenon-enhanced CT, 13 FDG-PET, 14,15 singlephoton emission CT, 16 and MR imaging spectroscopy.…”