qDESH: a method to quantify disproportionately enlarged subarachnoid space hydrocephalus.

Area of Science:

• Neurology
• Radiology
• Medical Imaging

Background:

• Disproportionately enlarged subarachnoid space (DESH) is a radiological biomarker for idiopathic normal pressure hydrocephalus (iNPH).
• Current visual assessment of DESH is subjective, potentially limiting its diagnostic reliability.
• Objective quantification of DESH is needed to improve iNPH diagnosis.

Purpose of the Study:

• To develop and validate an objective method for quantifying DESH.
• To establish a reliable measure for assessing DESH severity in iNPH patients.

Main Methods:

• A semiautomatic quantitative method (qDESH) was developed, calculating the ratio of CSF volumes at high convexities to Sylvian fissures.
• Analysis utilized 3D T1-weighted MRI from 35 iNPH patients and 45 controls.
• Interrater agreement for qDESH was assessed using the intraclass correlation coefficient and compared with visual assessments.

Main Results:

• Quantitative DESH (qDESH) demonstrated high accuracy in differentiating iNPH patients from controls (AUC=0.95).
• Median qDESH was significantly higher in iNPH patients (2.48) compared to controls (0.63).
• Excellent interrater agreement (ICC=0.99) was achieved for qDESH measurements.

Conclusions:

• Quantitative DESH (qDESH) provides a reproducible and objective measure of DESH severity.
• This method allows for objective investigation of DESH's diagnostic and prognostic value in iNPH.
• qDESH offers a significant advancement over subjective visual assessments for iNPH diagnosis.