Longitudinal Evolution of the Brain Microstructure in Cirrhotic Patients on Diffusion Kurtosis Imaging.

BACKGROUND: Although improvement of cognitive function after liver transplantation has been demonstrated in several neuropsychological studies, there is limited research on longitudinal changes in the cirrhotic patients' brain structure before and after transplantation. PURPOSE: To investigate longitudinal changes of brain microstructure in cirrhotic patients using diffusion kurtosis imaging (DKI). STUDY TYPE: Prospective. SUBJECTS: A total of 153 cirrhosis patients, comprising 60 hepatic encephalopathy (HE) patients (16 females/44 males) and 93 no-HE patients (35 females/58 males), along with 93 healthy controls (HCs) (53 females/40 males) were enrolled. Subsequently, 58 recipients completed 1-month postoperative follow-up, 29 patients completed 1-, 3-months, and 17 patients completed 1-, 3-, 6-month follow-up. SEQUENCE: Spin-echo single-shot echo-planar sequence using a 3.0 T scanner. ASSESSMENT: Diffusion kurtosis estimator software was used to estimate the DKI parameter maps by a MR imaging physicist (Y.-Y.C. with 12 years of experience). STATISTICAL TESTS: The diffusion metrics (eg, radial kurtosis [RK], mean kurtosis, fractional anisotropy, mean diffusivity) of the patients before transplantation were compared with those of the HCs using voxel-wise analysis of variance (ANOVA), along with t tests for post hoc analysis. Linear mixed-effects models were applied to the longitudinal data. We imposed a cluster level Family Wise Error (FWE) correction rate of PFWE = 0.05 with voxel-wise cutoff of P = 0.001 together with a cluster-size cutoff of N ≥ 56, and generated smoothness estimates from the preprocessed data using the mixed-model autocorrelation function. RESULTS: The RK metrics of the patients decreased significantly in the anterior cingulate cortex (HE/no-HE < HC, ANOVA-F = 21.91). After transplantation, the RK of the pallidum showed a continuous upward trend (time effect T = 11.26); whereas the RK of the right postcentral gyrus showed a continuous downward trend (time effect T = -9.56). In addition, the RK in superior longitudinal fasciculus showed new-onset decrease after transplantation. DATA CONCLUSION: Longitudinal changes in DKI metrics reveal the course of brain microstructural changes before and after transplantation in cirrhotic patients, potentially associated with cognitive alterations after surgery. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY: Stage 4.

Dynamic evolution of brain structural patterns in liver transplantation recipients: a longitudinal study based on 3D convolutional neuronal network model.

OBJECTIVES: To evaluate the dynamic evolution process of overall brain health in liver transplantation (LT) recipients, we employed a deep learning-based neuroanatomic biomarker to measure longitudinal changes of brain structural patterns before and 1, 3, and 6 months after surgery. METHODS: Because of the ability to capture patterns across all voxels from a brain scan, the brain age prediction method was adopted. We constructed a 3D-CNN model through T1-weighted MRI of 3609 healthy individuals from 8 public datasets and further applied it to a local dataset of 60 LT recipients and 134 controls. The predicted age difference (PAD) was calculated to estimate brain changes before and after LT, and the network occlusion sensitivity analysis was used to determine the importance of each network in age prediction. RESULTS: The PAD of patients with cirrhosis increased markedly at baseline (+ 5.74 years) and continued to increase within one month after LT (+ 9.18 years). After that, the brain age began to decrease gradually, but it was still higher than the chronological age. The PAD values of the OHE subgroup were higher than those of the no-OHE, and the discrepancy was more obvious at 1-month post-LT. High-level cognition-related networks were more important in predicting the brain age of patients with cirrhosis at baseline, while the importance of primary sensory networks increased temporarily within 6-month post-LT. CONCLUSIONS: The brain structural patterns of LT recipients showed inverted U-shaped dynamic change in the early stage after transplantation, and the change in primary sensory networks may be the main contributor. KEY POINTS: • The recipients' brain structural pattern showed an inverted U-shaped dynamic change after LT. • The patients' brain aging aggravated within 1 month after surgery, and the subset of patients with a history of OHE was particularly affected. • The change of primary sensory networks is the main contributor to the change in brain structural patterns.

Aberrant gray matter structure in neurosyphilis without conventional MRI abnormality: a pilot study with voxel and surface-based morphology.

BACKGROUND: The underlying mechanism of neurosyphilis was not fully understood. PURPOSE: To assess gray matter (GM) microstructure in patients with early-stage neurosyphilis without overt conventional magnetic resonance imaging (MRI) abnormality using voxel-based morphometry (VBM) and surface-based morphometry (SBM) analyses. MATERIAL AND METHODS: Three-dimensional high-resolution T1-weighted imaging data from 19 individuals with neurosyphilis and 19 healthy controls were analyzed. A battery of neuropsychological tests was performed before each MRI examination. The differences of GM volume and cerebral cortical morphological data between the two groups were compared. The correlations between MRI metrics and neuropsychology/laboratory tests in the patient group were investigated. RESULTS: Regional decreased GM volumes in patients with neurosyphilis were found in the left frontal cortices (Rolandic operculum, middle frontal, and precentral) and bilateral temporal/occipital cortices (bilateral middle temporal, left lingual, and right middle occipital) (P < 0.05, FDR correction). SBM analysis showed significant cortical thickness reduction in the right medial orbitofrontal lobe, and reduced gyrification index in the left insula in patients with neurosyphilis (P < 0.05, FDR correction). Additionally, in the patient group, the GM volume in the middle frontal gyrus, the cortical thickness of right medial orbitofrontal lobe, and the gyrification index in the left insula were negatively correlated to the number connection test-A scores. The gyrification index was also negatively correlated to cerebrospinal fluid white blood cell count. CONCLUSION: Early-stage neurosyphilis without conventional MRI abnormality presented regional GM volume reduction and cortical morphological changes, which might be related to cognitive impairment and intra-cranial infection. VBM and SBM analyses might be useful for understanding the underlying neural trait of neurosyphilis.

Altered white matter structural connectivity in primary Sjögren's syndrome: a link-based analysis.

PURPOSE: Cognitive impairment has been revealed in primary Sjögren's syndrome (pSS). However, the underlying white matter structural connectivity (SC) changes have not been studied. This study aimed to investigate the altered white matter brain network in patients with pSS using diffusion tensor imaging (DTI). METHODS: Forty-one pSS patients and sixty matched healthy controls (HCs) underwent neuropsychological tests and the subsequent MRI examinations. The clinical data were gathered from the medical record. The structural brain network was established using DTI, and a link-based comparison was performed between patients with pSS and HCs (false discovery rate correction, P < 0.05). Furthermore, the mean fractional anisotropy (FA) of the altered SCs was correlated with the neuropsychological tests and clinical data in patients with pSS (Bonferroni correction, P < 0.05). RESULTS: Compared with HCs, patients with pSS mainly exhibited decreased SC in the frontal and parietal lobes and some parts of the temporal and occipital lobes. In addition, increased SC was found between the right caudate nucleus and right median cingulate/paracingulate gyri. Specifically, the reduced SC between the left middle temporal gyrus and left middle occipital gyrus was negatively correlated with white matter high signal intensity (WMH). CONCLUSIONS: Patients with pSS showed diffusely decreased SC mainly in the frontoparietal network and exhibited a negative correlation between the reduced SC and WMH. SC represents a potential biomarker for preclinical brain impairment in patients with pSS.