Function–structure connectivity in patients with severe brain injury as measured by MRI‐DWI and FDG‐PET

Abstract

A vast body of literature exists showing functional and structural dysfunction within the brains of patients with disorders of consciousness. However, the function (fluorodeoxyglucose FDG-PET metabolism)-structure (MRI-diffusion-weighted images; DWI) relationship and how it is affected in severely brain injured patients remains ill-defined. FDG-PET and MRI-DWI in 25 severely brain injured patients (19 Disorders of Consciousness of which 7 unresponsive wakefulness syndrome, 12 minimally conscious; 6 emergence from minimally conscious state) and 25 healthy control subjects were acquired here. Default mode network (DMN) function-structure connectivity was assessed by fractional anisotropy (FA) and metabolic standardized uptake value (SUV). As expected, a profound decline in regional metabolism and white matter integrity was found in patients as compared with healthy subjects. Furthermore, a function-structure relationship was present in brain-damaged patients between functional metabolism of inferior-parietal, precuneus, and frontal regions and structural integrity of the frontal-inferiorparietal, precuneus-inferiorparietal, thalamo-inferioparietal, and thalamofrontal tracts. When focusing on patients, a stronger relationship between structural integrity of thalamoinferiorparietal tracts and thalamic metabolism in patients who have emerged from the minimally conscious state as compared with patients with disorders of consciousness was found. The latter finding Additional Supporting Information may be found in the online version of this article.

Metaplasticity: A Promising Tool to Disentangle Chronic Disorders of Consciousness Differential Diagnosis

“…The premotor-motor excitability was clearly deteriorated in the patients with DoC in correlation with the CRS-R score. This further confirms that a connectivity breakdown within distinct cortical areas accounts for the loss of consciousness in patients with DoC, [111][112][113][114][115] and suggests that the connectivity impairment between premotor and motor cortices is significant to cause motor output deterioration, even when a patient shows a partially preserved whole brain connectivity. 29,30,116 One could argue that the lack of conditioning after-effects in patients with DoC may depend on the fact that TDCS fails to recruit the SICI networks, 117,118 rather than on a low amount of plasticity.…”

High angular resolution diffusion-weighted imaging in mild traumatic brain injury

“…However, 64 gradient orientations were likely sufficient and crossing fibers could reliably be detected as previously shown in e.g. (Annen et al, 2016, Roine et al, 2015b, Roine et al, 2015c). In addition, patients in both acute and sub-acute stages of mTBI were included in this study, which might have affected the results although within this time range our results did not correlate with the time from injury.…”

Decreased integration of EEG source-space networks in disorders of consciousness

“…Severe brain damages may lead to various disorders of consciousness (DOC; (Giacino et al, 2014)). Emerging evidence associates DOC with alterations in functional and/or structural brain networks, mainly those sustaining arousal and awareness (Owen et al, 2009;Boly et al, 2012;Fernández-Espejo et al, 2012;Annen et al, 2016;Amico et al, 2017;Bodien et al, 2017;Annen et al, 2018). Therefore, network-based EEG methods enabling the identification of these pathological alterations in brain networks are valuable.…”