A combined diffusion tensor imaging and magnetic resonance spectroscopy study of patients with schizophrenia

Abstract

Diffusion tensor imaging (DTI) studies in schizophrenia consistently show global reductions in fractional anisotropy (FA), a putative marker of white matter integrity. The cingulum bundle, which facilitates communication between the anterior cingulate cortex (ACC) and hippocampus, is frequently implicated in schizophrenia. Magnetic resonance spectroscopy (MRS) studies report metabolic abnormalities in the ACC and hippocampus of patients. Combining DTI and MRS offers exploration of the relationship between cortical neuronal biochemistry and the integrity of white matter tracts connecting specific cortical regions; however, few studies have attempted this in schizophrenia. Twenty-nine schizophrenia patients and twenty controls participated in this 3T imaging study in which we used DTI and tract-based spatial statistics (TBSS) to assess white matter integrity and MRS to quantify metabolites in the ACC and hippocampus. We found FA reductions with overlapping radial diffusivity (RD) elevations in patients in multiple tracts, suggesting white matter abnormalities in schizophrenia are driven by loss of myelin integrity. In controls, we found significant negative correlations between hippocampal N-acetylaspartate/creatine and RD and axial diffusivity (AD) as well as a significant negative correlation between FA and ACC glutamate+glutamine/creatine in the hippocampal part of the cingulum bundle. It is possible that the extent of myelin damage could have resulted in the absence of DTI–MRS correlations in our patient group. In conclusion, we demonstrate the potential utility of a multi-modal neuroimaging approach to help further our understanding of the relationship between white matter microstructure and neurochemistry in distinct cortical regions connected by white matter tracts.

The details of structural disconnectivity in psychotic disorder: A family-based study of non-FA diffusion weighted imaging measures

“…The absence of differences in AXD between patients and controls is consistent with previous whole brain voxel-wise studies (Kikinis et al, 2015;Lee et al, 2013;Reid et al, 2016;Scheel et al, 2013;Seal et al, 2008;Zeng et al, 2016), denoting preservation of axonal cells in the white matter (Song et al, 2003). This indicates that the decrease in FA in the patients, as reported previously (Domen et al, 2013), may not be related to a reduction in the number of axons.…”

“…In the present study, clusters of significantly increased RD were dispersed over the brain and also represented in the corpus callosum of patients with psychotic disorder. Previous whole brain voxel-wise studies (K. Clark et al, 2012;Koch et al, 2011;Lu et al, 2011;Reid et al, 2016;Whitford et al, 2010) and region of interest based studies (McCarthy-Jones et al, 2015;Ohtani et al, 2014;Seitz et al, 2016) in psychotic disorder have found similar increases in RD, although some region of interest studies reported reduced RD in specific areas (Carletti et al, 2012;Kikinis et al, 2015;Koch et al, 2011). In addition, increased RD has been found in individuals at ultra high-risk for psychotic disorder (Carletti et al, 2012), suggesting that alterations may already be present in the prodromal stages.…”

Four‐way multimodal fusion of 7 T imaging data using an mCCA+jICA model in first‐episode schizophrenia

“…WM IC3 brainstem abnormalities could be indicative of the role the dopaminergic neurons in the brainstem play in thalamocorticostriatal circuit dysfunction implicated in schizophrenia (Ellison‐Wright et al, ). Furthermore, internal capsule abnormalities demonstrated in WM IC3 are supported by the literature (Di, Chan, & Gong, ; Horga et al, ; Lyu et al, ; Reid, White, Kraguljac, & Lahti, ). In fact, Horga and colleagues proposed that alterations in internal capsule could be a result of ventricular expansion consistently demonstrated in schizophrenia (Horga et al, ).…”

White matter microstructure and network-connectivity in emerging adults with subclinical psychotic experiences

“…Basser and Pierpaoli 2011). Previous research on patients with psychotic disorder suggests that AXD is unaffected (Kikinis et al 2015;Reid et al 2016;Scheel et al 2013), whereas RAD and MD may be increased with respect to controls (Ardekani et al 2011;Clark et al 2011;Zeng et al 2016). In addition, higher levels of positive psychotic symptoms have been associated with a decrease in FA (Lener et al 2015;A.…”