The midbrain to pons ratio

Abstract

Objectives: MRI-based measurements used to diagnose progressive supranuclear palsy (PSP) typically lack pathologic verification and are not easy to use routinely. We aimed to develop in histologically proven disease a simple measure of the midbrain and pons on sagittal MRI to identify PSP.Methods: Measurements of the midbrain and pontine base on midsagittal T1-weighted MRI were performed in confirmed PSP (n 5 12), Parkinson disease (n 5 2), and multiple system atrophy (MSA) (n 5 7), and in controls (n 5 8). Using receiver operating characteristic curve analysis, cutoff values were applied to a clinically diagnosed cohort of 62 subjects that included PSP (n 5 21), Parkinson disease (n 5 10), MSA (n 5 10), and controls (n 5 21). Results:The mean midbrain measurement of 8.1 mm was reduced in PSP (p , 0.001) with reduction in the midbrain to pons ratio (PSP smaller than MSA; p , 0.001). In controls, the mean midbrain ratio was approximately two-thirds of the pontine base, in PSP it was ,52%, and in MSA the ratio was greater than two-thirds. A midbrain measurement of ,9.35 mm and ratio of 0.52 had 100% specificity for PSP. In the clinically defined group, 19 of 21 PSP cases (90.5%) had a midbrain measurement of ,9.35 mm. Conclusions:We have developed a simple and reliable measurement in pathologically confirmed disease based on the topography of atrophy in PSP with high sensitivity and specificity that may be a useful tool in the clinic. Neurodegenerative diseases presenting with parkinsonism including idiopathic Parkinson disease (PD), progressive supranuclear palsy (PSP), and multiple system atrophy (MSA) can be difficult to differentiate clinically particularly early in the disease course.1 Characteristic midbrain atrophy in PSP and pontine atrophy in MSA can be assessed on MRI 2 ; however, many magnetic resonance-based measurements proposed as diagnostic for PSP or MSA lack pathologic verification and are often not easy to apply routinely. [3][4][5][6][7][8][9] Our hypothesis was that simple measurements of the midbrain and pons (or their ratio) on midsagittal MRI would identify confirmed PSP and MSA.METHODS Standard protocol approvals, registrations, and patient consents. A pathologically confirmed cohort of PSP, PD, and MSA subjects (table 1) was selected from the Queen Square Brain Bank at UCL Institute of Neurology; brains were donated following ethically approved protocols under license from the Human Tissue Authority. A cohort of PSP, PD, MSA, and healthy subjects was prospectively recruited at the National Hospital for Neurology and Neurosurgery, as part of an ethically approved study with written informed consent.Participants and protocols. In the pathologically confirmed group, the diagnosis was determined using standard neuropathologic criteria. 10 In the clinically diagnosed group, participants fulfilled operational criteria 11-13 and were assessed with clinimetric scales including Hoehn and Yahr,

Progression of brain atrophy in PSP and CBS over 6 months and 1 year

“…The similarity of ROI-measured atrophy rates between PSP and PSP-DAV supports the conclusion that the larger PSP-DAV sample size enabled detection of smaller cortical changes using VBM maps, which indicate statistical significance but not magnitude. In addition, the midbrain to pons ratio, which has previously been shown to be decreased in PSP, [26][27][28][29][30] was nearly identical in the PSP and PSP-DAV groups and smaller than in the CBS or NC group. Future studies of autopsy-confirmed CBD and PSP cases will be necessary to definitively determine the differences in rates of volume loss between these disorders.…”

“…[26][27][28][29][30] At all time points, both PSP and PSP-DAV groups had lower midbrain to pons ratios than NC and CBS groups (figure e-2). Moreover, midbrain/pons ratios within all groups remained stable over 1 year in all groups.…”

Dynamic Cerebrospinal Fluid Flow on MRI in Cortical Cerebellar Atrophy and Multiple System Atrophy-cerebellar Type

“…The placement of ROI was determined by a previous report (13). Elliptical ROI were placed over the pons in the midsagittal slice (Fig.…”

“…In all cases, the posterior border of the pontine base was clearly identified and did not include the pontine tegmentum. All measurements were performed by another rater who was blinded to the clinical information (13).…”

No relevant midbrain atrophy in Parkinson's disease

“…It is reflected in the hummingbird sign, which appears to show some specificity for PSP (1,2), although negative results have also been reported (3). Midbrain atrophy can also be observed in vascular parkinsonism (4), primary progressive apraxia of speech (5), and dementia with Lewy bodies (6).…”