Detection of Communicating Hydrocephalus

Value Proposition

Normal pressure hydrocephalus, a variant of communicating hydrocephalus, is an underdiagnosed, reversible cause of dementia (Jaraj 2014). Radiologists have difficulty in distinguishing communicating hydrocephalus from normal aging and other dementias (Serulle 2014). Quantitative measurements such as the Evans index and callosal angle are useful, objective data for identifying communicating hydrocephalus (Miskin 2017).

Narrative(s)

An 85 year-old man presents to a neurology clinic with progressive cognitive decline and difficulty walking. Review of symptoms, Mini-Mental State Examination (MMSE), and gait evaluation are concerning for normal pressure hydrocephalus. The neurologist orders a non-contrast brain MRI for further evaluation.

Workflow Description

Volumetric coronal T1-weighted images are reconstructed perpendicular to the anterior commisure-posterior commisure plane, and a callosal angle is automatically measured at the level of the posterior commisure. An Evans index is also generated by measurements of the largest bi-frontal ventricular diameter in the axial plane divided by the maximum skull width at that level (inner table to inner table). Two annotated images are generated displaying each measurement for the radiologist to review. The generated measurements and the interpreting radiologist's subjective assessment of sulcal effacement at the vertex and widening of the Sylvian fissures are used to confirm the diagnosis. These additional more subjective findings can also be analyzed utilizing AI algorithms.

Inputs

DICOM Study

Primary Outputs

Callosal angle

Evans Index

Jaraj D, Rabiei K, Marlow T, Jensen C, Skoog I, Wikkelsø C. Prevalence of idiopathic normal-pressure hydrocephalus. Neurology. 2014;82(16):1449-54.

Serulle Y, Rusinek H, Kirov II, et al. Differentiating shunt-responsive normal pressure hydrocephalus from Alzheimer disease and normal aging: pilot study using automated MRI brain tissue segmentation. J Neurol. 2014;261(10):1994-2002.

Miskin N, Patel H, Franceschi AM, et al. Diagnosis of Normal-Pressure Hydrocephalus: Use of Traditional Measures in the Era of Volumetric MR Imaging. Radiology. 2017;285(1):197-205.