Linear vs volume measures of ventricle size in hydrocephalus: relation to present and future gait and cognition

Objective To compare the clinical utility of volume-based ratios with the standard linear ratio of Evans index (EI) by examining their associations with gait, cognition, and other patient and imaging variables. 

 Methods From MRI scans of 1,774 participants in the Mayo Clinic Study of Aging, we calculated 3 ventricle size measures: Evan index (frontal horn width divided by widest width of skull inner table), total ventricular volume, and frontal horn volume as ratios of total intracranial volume. Gait was measured by a timed 25-foot walk and cognition by a composite of psychometric tests. We also evaluated variables associated with the measures of ventricular size. Further, we evaluated gait and cognition associations with MRI of extraventricular findings seen in normal-pressure hydrocephalus: disproportionate enlargement of subarachnoid space (DESH) and focal sulcal dilations (FSD). 

 Results Ventricular volume measures had stronger association with gait and cognition measures than EI. In decreasing order of strength of association with ventricle size were DESH, FSD, white matter hyperintensity volume ratio, age, male sex, cortical thickness, and education. Modest evidence was observed that FSD was associated with future decline in gait and cognition. 

 Conclusion Ventricular volume measures are clinically more useful than EI in indicating current and future gait and cognition. Multiple factors are associated with ventricle volume size, including FSD and DESH, suggesting that changes in CSF dynamics may go beyond simple ventriculomegaly. 

 DOI: https://doi.org/10.1212/WNL.0000000000008673

A new MR imaging index for differentiation of progressive supranuclear palsy-parkinsonism from Parkinson's disease

Highlights

• Distinguishing PSP-P from PD is challenging in the early stages of the disease.
• Few data exist on the usefulness of MRPI for diagnosing PSP-P patients.
• MRPI 2.0 is a new version of MRPI which includes the 3rd ventricular width
• MRPI 2.0 accurately differentiated patients with PSP-P from those with PD.
• MRPI 2.0 accurately diagnosed PSP-P in the absence of vertical ocular palsy.

Reference: Quattrone A, Morelli M, Nigro S, Quattrone A, Vescio B, Arabia G, Nicoletti G,Nisticò R, Salsone M, Novellino F, Barbagallo G, Le Piane E, Pugliese P, Bosco D, Vaccaro MG, Chiriaco C, Sabatini U, Vescio V, Stanà C, Rocca F, Gullà D, Caracciolo M. A new MR imaging index for differentiation of progressive supranuclear palsy-parkinsonism from Parkinson's disease. Parkinsonism Relat Disord. 2018 Sep;54:3-8. doi: 10.1016/j.parkreldis.2018.07.016

Corpus Callosum Index: A practical method for long-term follow-up in multiple sclerosis

Corpus callosum index

References

Pérez-Álvarez AI, Suárez-Santos P, González-Delgado M, Oliva-Nacarino P. Quantification of brain atrophy in multiple sclerosis using two-dimensional measurements. Neurologia. 2018 Jun 8. pii: S0213-4853(18)30152-X. doi: 10.1016/j.nrl.2018.04.004
Figueira, Fernando Faria Andrade, Santos, Valeria Silva dos, Figueira, Gustavo Medeiros Andrade, & Silva, Ângela Correa Marques da. (2007). Corpus Callosum Index: A practical method for long-term follow-up in multiple sclerosis. Arquivos de Neuro-Psiquiatria, 65(4a), 931-935. https://dx.doi.org/10.1590/S0004-282X2007000600001

Linear measures for assessing gray matter atrophy in Multiple Sclerosis

The the bicaudate ratio (BCR) is increased in MS and is more closely associated with cognitive dysfunction than are other magnetic resonance imaging surrogate markers including whole-brain atrophy. Increased BCR is best explained by frontal horn ventricular enlargement due to atrophy of deep frontal subcortical white matter. This highlights the close relationship between subcortical atrophy and cognitive impairment in patients with MS (read more) and AD (read more).

Fluid-attenuated inversion-recovery magnetic resonance imaging scan of a patient with multiple sclerosis showing the technique of determining the bicaudate ratio (BCR). The BCR is the minimum intercaudate distance (solid line) divided by brain width along the same line (dashed line).

Bicaudate ratio. The yellow represents the distance between the two apices of the caudate nuclei. The inner skull dimension is shown in turquoise. The bicaudate ratio is derived by dividing the ventricular dimension (yellow) by the inner skull dimension

However, although the bicaudate ratio is a fairly good measure of caudate atrophy, seems to be poor measures of caudate size when no atrophy is present (read more).