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Midbrain morphology in idiopathic normal pressure hydrocephalus: A progressive supranuclear palsy mimic
Author(s) -
Constantinides Vasilios C.,
Paraskevas George P.,
Velonakis Georgios,
Toulas Panagiotis,
Stefanis Leonidas,
Kapaki Elisabeth
Publication year - 2020
Publication title -
acta neurologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.967
H-Index - 95
eISSN - 1600-0404
pISSN - 0001-6314
DOI - 10.1111/ane.13205
Subject(s) - progressive supranuclear palsy , midbrain , parkinsonism , magnetic resonance imaging , medicine , pathology , atrophy , nuclear medicine , psychology , radiology , central nervous system , disease
Various MRI markers have been applied to support the diagnosis of progressive supranuclear palsy (PSP), such as midbrain diameter and surface, superior cerebellar peduncle (SCP) width, midbrain to pons (m/p) diameter and surface ratio and the Magnetic Resonance Parkinsonism Index (MRPI). These markers provide excellent diagnostic accuracy in discriminating Richardson's syndrome from other causes of Parkinsonism. Idiopathic normal pressure hydrocephalus (iNPH) may mimic Richardson's syndrome, particularly in cases of subtle opthalmokinetic abnormalities. The aim of this study was to compare these MRI markers in PSP and iNPH and examine their diagnostic accuracy. Materials and Methods Forty‐three patients with probable PSP, 17 patients with iNPH, and 29 controls were included. Midbrain diameter and surface, SCP width, m/p diameter and surface ratio and the MRPI were recorded. The “hummingbird sign,” “morning glory sign” and “mickey mouse sign” were also evaluated. Analysis of covariance, chi‐squared test, and ROC curve analysis were used as appropriate. Results All MRI measurements differed significantly among the three study groups. Comparison of PSP and iNPH patients produced the following significant differences: midbrain diameter ( P < .0001), m/p diameter ratio ( P < .0001), SCP width ( P = .050), and MRPI ( P = .049). None of these markers produced combined high (>80%) specificity and sensitivity. Qualitative MRI signs were specific, but lacked sensitivity. Discussion Midbrain morphology in iNPH may resemble that of PSP. Established MRI markers of midbrain and SCP atrophy cannot confidently differentiate PSP from iNPH. MRI markers do not provide combined high sensitivity and specificity for the differential diagnosis of PSP from iNPH.