Reduced Gray to White Matter Tissue Intensity Contrast in Schizophrenia

Abstract

BackgroundWhile numerous structural magnetic resonance imaging (MRI) studies revealed changes of brain volume or density, cortical thickness and fibre integrity in schizophrenia, the effect of tissue alterations on the contrast properties of neural structures has so far remained mostly unexplored.MethodsWhole brain high-resolution MRI at 3 Tesla was used to investigate tissue contrast and cortical thickness in patients with schizophrenia and healthy controls.ResultsPatients showed significantly decreased gray to white matter contrast in large portions throughout the cortical mantle with preponderance in inferior, middle, superior and medial temporal areas as well as in lateral and medial frontal regions. The extent of these intensity contrast changes exceeded the extent of cortical thinning. Further, contrast changes remained significant after controlling for cortical thickness measurements.ConclusionsOur findings clearly emphasize the presence of schizophrenia related brain tissue changes that alter the imaging properties of brain structures. Intensity contrast measurements might not only serve as a highly sensitive metric but also as a potential indicator of a distinct pathological process that might be independent from volume or thickness alterations.

Association of Cortical Thickness and Neurological Soft Signs in Patients with Chronic Schizophrenia and Healthy Controls

“…Variations in each of these parameters may have distinct physiological implications [49]. Therefore, using a specific measurement such as cortical thickness [8] will be more sensitive than using combined measurements, which is also supported by our and other previous results [50,51]. Third, the present study also addressed the relationship between cortical thickness and NSS in healthy controls.…”

Comparison of grey matter volume and thickness for analysing cortical changes in chronic schizophrenia: A matter of surface area, grey/white matter intensity contrast, and curvature

“…A study by Palaniiyappan and Liddle (2012) demonstrated that changes of cortical thickness, gyrification and surface area could mediate changes of grey matter volume in schizophrenia, but did not account for all the variances of grey matter volume . A recent study by Kong et al (2012) demonstrated grey/white matter intensity contrast changes which were similar to, but more widespread than, the changes in cortical thickness in schizophrenia, and which overlapped to some extent with the regions showing grey matter volume reduction in VBM studies . Therefore, grey/white matter intensity contrast could also be a contributor to grey matter volume changes and might account for some discrepancies between grey matter volume and thickness.…”

Neurological Soft Signs and Brainstem Morphology in First-Episode Schizophrenia

“…However, given the nature of a structural MRI study, this interpretation is highly speculative and the precise nature of biological changes that could lead to the observed morphological changes in the brainstem remains elusive. Apart from deficient myelination, potential pathological mechanisms could include changes of water content in myelin, increased MR-visible axonal cytosol resulting from alterations in the microtubular density of axons, and neuronal degeneration, amongst others [62]. A previous study on adolescents at risk for schizophrenia suggested cortical volumetric, shape and thickness measures as parameters that are differentially linked to neurodevelopmental processes [63].…”