Feasibility of Non-Gaussian Diffusion Metrics in Chronic Disorders of Consciousness.

Ivan I Maximov,Michael A Piradov,Liudmila A Legostaeva,Aleksandr S Suslin,Marina V Krotenkova,Dmitry O Sinitsyn,Elena I Kremneva,Natalia A Suponeva,Dmitry V Sergeev,Elizaveta G Iazeva,Sofya N Morozova

doi:10.3390/brainsci9050123

Abstract

Diagnostic accuracy of different chronic disorders of consciousness (DOC) can be affected by the false negative errors in up to 40% cases. In the present study, we aimed to investigate the feasibility of a non-Gaussian diffusion approach in chronic DOC and to estimate a sensitivity of diffusion kurtosis imaging (DKI) metrics for the differentiation of vegetative state/unresponsive wakefulness syndrome (VS/UWS) and minimally conscious state (MCS) from a healthy brain state. We acquired diffusion MRI data from 18 patients in chronic DOC (11 VS/UWS, 7 MCS) and 14 healthy controls. A quantitative comparison of the diffusion metrics for grey (GM) and white (WM) matter between the controls and patient group showed a significant (p < 0.05) difference in supratentorial WM and GM for all evaluated diffusion metrics, as well as for brainstem, corpus callosum, and thalamus. An intra-subject VS/UWS and MCS group comparison showed only kurtosis metrics and fractional anisotropy differences using tract-based spatial statistics, owing mainly to macrostructural differences on most severely lesioned hemispheres. As a result, we demonstrated an ability of DKI metrics to localise and detect changes in both WM and GM and showed their capability in order to distinguish patients with a different level of consciousness.

Highlights

The term “consciousness” in clinical practice is defined as the presence of two main components: wakefulness and awareness [1]
We aimed to investigate the question of whether the diffusion kurtosis metrics provide enriched information and a more sensitive chronic disorders of consciousness (DOC) differentiation criterion compared to the diffusion tensor imaging (DTI) metrics regarding tissue changes following anoxia and severe chronic traumatic brain injury (TBI)
In our study we found dramatic diffusion metric changes in all regions of interest such as increased MD, axial kurtosis diffusivity (AD), radialkurtosis diffusivity (RD) and decreased kurtosis values in patients comparing to the healthy controls

Summary

Introduction

The term “consciousness” in clinical practice is defined as the presence of two main components: wakefulness and awareness [1]. But signs of awareness are absent, the patient is referred to having vegetative state/unresponsive wakefulness syndrome (VS/UWS). If any evidence of awareness along with wakefulness cycle can be seen, a clinician may diagnose a minimally conscious state (MCS) [2,3]. The mentioned two states are difficult to differentiate unambiguously since clinical evaluation is often subjective and based solely on clinical behavioural scales that can be influenced by sensorimotor impairment, unnoticeable motor activity, pain, apraxia, aphasia, deafness etc. Since the correct diagnosis in disorders of consciousness (DOC) is of great importance for a selection of rehabilitation strategy, recovery prognosis and support of patient family, many researchers try to find reliable objective biomarkers to estimate the level of consciousness

Objectives

Methods

Results

Discussion

Conclusion