Dopaminergic imaging separates normal pressure hydrocephalus from its mimics

Area of Science:

• Neurology
• Neuroimaging
• Nuclear Medicine

Background:

• Idiopathic normal pressure hydrocephalus (iNPH) shares clinical symptoms with mimic conditions like Parkinson's disease, leading to diagnostic challenges.
• Distinguishing iNPH from mimics often requires invasive and time-consuming investigations.

Purpose of the Study:

• To compare visual and semi-quantitative [123I]FP-CIT SPECT imaging in differentiating iNPH from iNPH mimics.
• To evaluate [123I]FP-CIT SPECT as a potential biomarker for iNPH diagnosis.

Main Methods:

• 56 patients with suspected iNPH were assessed, with 26 diagnosed with iNPH and 30 as mimics.
• Visual assessment and semi-quantitative striatal binding ratios (SBR) of [123I]FP-CIT SPECT were analyzed.
• Logistic regression was used to determine the association between SPECT findings and diagnosis.

Main Results:

• A normal SBR on [123I]FP-CIT SPECT was observed in 69.2% of iNPH patients versus 37.9% of mimics (p=0.020).
• Visual assessment of SPECT scans did not significantly differ between the groups.
• Normal SBR values were significantly associated with an iNPH diagnosis, even after adjusting for confounding factors (aOR=4.17).

Conclusions:

• Semi-quantitative [123I]FP-CIT SPECT analysis effectively discriminates iNPH from its mimics.
• Visual assessment of [123I]FP-CIT SPECT is insufficient for differentiation.
• [123I]FP-CIT SPECT shows promise as a neuroimaging biomarker to improve patient selection for iNPH interventions.