Diffusional kurtosis imaging and white matter microstructure modeling in a clinical study of major depressive disorder

Abstract

Major depressive disorder (MDD) is a globally prevalent psychiatric disorder that results from disruption of multiple neural circuits involved in emotional regulation. Although previous studies using diffusion tensor imaging (DTI) found smaller values of fractional anisotropy (FA) in the white matter, predominantly in the frontal lobe, of patients with MDD, studies using diffusion kurtosis imaging (DKI) are scarce. Here, we used DKI whole‐brain analysis with tract‐based spatial statistics (TBSS) to investigate the brain microstructural abnormalities in MDD. Twenty‐six patients with MDD and 42 age‐ and sex‐matched control subjects were enrolled. To investigate the microstructural pathology underlying the observations in DKI, a compartment model analysis was conducted focusing on the corpus callosum. In TBSS, the patients with MDD showed significantly smaller values of FA in the genu and frontal portion of the body of the corpus callosum. The patients also had smaller values of mean kurtosis (MK) and radial kurtosis (RK), but MK and RK abnormalities were distributed more widely compared with FA, predominantly in the frontal lobe but also in the parietal, occipital, and temporal lobes. Within the callosum, the regions with smaller MK and RK were located more posteriorly than the region with smaller FA. Model analysis suggested significantly smaller values of intra‐neurite signal fraction in the body of the callosum and greater fiber dispersion in the genu, which were compatible with the existing literature of white matter pathology in MDD. Our results show that DKI is capable of demonstrating microstructural alterations in the brains of patients with MDD that cannot be fully depicted by conventional DTI. Though the issues of model validation and parameter estimation still remain, it is suggested that diffusion MRI combined with a biophysical model is a promising approach for investigation of the pathophysiology of MDD.

Intravoxel incoherent motion diffusion MR and diffusion kurtosis imaging for discriminating atypical bone metastasis from benign bone lesion

“…DKI can reflect tissue microstructure more accurately. 13 DKI derived MK reflects diffusion heterogeneity that correlates with tissue complexity.…”

Abnormal structural brain network and hemisphere-specific changes in bulimia nervosa

“…Future researches comparing the structural networks between adult and adolescent patient groups will help to determine development-related changes. Third, the disorder specificity of the findings to BN remains to be clarified given that studies 54–56 investigated the WM integrity in mood, psychotic, and substance use disorders found reduced FA in a multitude of regions overlapped with our study. A direct comparison with AN and other patient groups will be necessary to clarify this issue.…”

Role of diffusion kurtosis imaging for detecting brain microstructural changes in complete remission childhood survivors undergoing chemotherapy for acute lymphoblastic leukemia

“…Diffusion kurtosis imaging (DKI) extends conventional DTI by estimating the diffusion and kurtosis tensors to quantify non-Gaussian diffusion that occurs in biological tissues [10,11]. Studies have proved that DKI is more comprehensive and sensitive than DTI in characterizing normal or pathological brain tissues [12,13]. Currently, most microstructural studies on the brains of children with ALL are mainly focused on long-term changes after chemotherapy; short-term studies are lacking.…”