Structural and functional brain connectivity in moderate-late preterm infants with low-grade intraventricular hemorrhage.

PURPOSE: Brain functional connectivity (FC) changes and microstructural abnormalities are reported in infants born moderate and late preterm (MLPT). We evaluated the effect of low-grade (grades I, II) intraventricular hemorrhage (IVH) in MLPT babies on brain structural connectivity (SC) and FC. METHODS: Babies born MLPT between January 2014 and May 2017 underwent brain ultrasound (US) at 72 h and 7 days after birth, and MRI at around term equivalent. The MRI protocol comprised T1- and T2-weighted sequences, diffusion tensor imaging (DTI), and resting-state functional MRI (fMRI). SC and FC were assessed using graph analysis. RESULTS: Of 350 MLPT neonates, 15 showed low-grade IVH on US at 72 h, for which brain MRI was available in 10. These 10 infants, with mean gestational age (GA) 34.0 ± 0.8 weeks, comprised the study group, and 10 MLPT infants of mean GA 33.9 ± 1.1 weeks, with no abnormalities on brain US and MRI, were control subjects. All study subjects presented modularity, small world topology, and rich club organization for both SC and FC. The patients with low-grade IVH had lower FC rich club coefficient and lower SC betweenness centrality in the left frontoparietal operculum, and lower SC rich club coefficient in the right superior orbitofrontal cortex than the control subjects. CONCLUSIONS: Topological and functional properties of mature brain connectivity are present in MLPT infants. IVH in these infants was associated with structural and functional abnormalities in the left frontoparietal operculum and right orbitofrontal cortex, regions related to language and cognition.

Functional and structural connectivity of the brain in very preterm babies: relationship with gestational age and body and brain growth.

BACKGROUND: Structural and functional changes of the brain have been reported in premature babies. OBJECTIVE: To evaluate the relationship of functional and structural connectivity with gestational age, body growth and brain maturation in very preterm babies. MATERIALS AND METHODS: We studied 18 very preterm babies (gestational age: mean ± standard deviation, 29.7±1.7 weeks). We examined functional connectivity by multivariate pattern analysis of resting-state functional MRI data. We assessed structural connectivity by analysis of diffusion tensor imaging data and probabilistic tractography. RESULTS: The average functional connectivity of the medial orbitofrontal cortex with the rest of the brain was positively associated with gestational age (P<0.001). Fractional anisotropy of the right inferior fronto-occipital fasciculus was positively associated with head circumference at term-equivalent age. Structural connectivity of the inferior fronto-occipital fasciculus with the medial orbitofrontal cortex was positively associated with head circumference at term-equivalent age. Body weight at term-equivalent age was the only independent predictor of average structural connectivity of the medial orbitofrontal cortex with the rest of the brain (P=0.020). CONCLUSION: Structural and functional connectivity of the medial orbitofrontal cortex with the rest of the brain depend on body growth and degree of prematurity, respectively.

Diffusion tensor imaging in children with tuberous sclerosis complex: tract-based spatial statistics assessment of brain microstructural changes.

BACKGROUND: There is evidence of microstructural changes in normal-appearing white matter of patients with tuberous sclerosis complex. OBJECTIVE: To evaluate major white matter tracts in children with tuberous sclerosis complex using tract-based spatial statistics diffusion tensor imaging (DTI) analysis. MATERIALS AND METHODS: Eight children (mean age ± standard deviation: 8.5 ± 5.5 years) with an established diagnosis of tuberous sclerosis complex and 8 age-matched controls were studied. The imaging protocol consisted of T1-weighted high-resolution 3-D spoiled gradient-echo sequence and a spin-echo, echo-planar diffusion-weighted sequence. Differences in the diffusion indices were evaluated using tract-based spatial statistics. RESULTS: Tract-based spatial statistics showed increased axial diffusivity in the children with tuberous sclerosis complex in the superior and anterior corona radiata, the superior longitudinal fascicle, the inferior fronto-occipital fascicle, the uncinate fascicle and the anterior thalamic radiation. No significant differences were observed in fractional anisotropy, mean diffusivity and radial diffusivity between patients and control subjects. No difference was found in the diffusion indices between the baseline and follow-up examination in the patient group. CONCLUSION: Patients with tuberous sclerosis complex have increased axial diffusivity in major white matter tracts, probably related to reduced axonal integrity.

Survival Outcome Prediction in Glioblastoma: Insights from MRI Radiomics.

Background: Extracting multiregional radiomic features from multiparametric MRI for predicting pretreatment survival in isocitrate dehydrogenase (IDH) wild-type glioblastoma (GBM) patients is a promising approach. Methods: MRI data from 49 IDH wild-type glioblastoma patients pre-treatment were utilized. Diffusion and perfusion maps were generated, and tumor subregions segmented. Radiomic features were extracted for each tissue type and map. Feature selection on 1862 radiomic features identified 25 significant features. The Cox proportional-hazards model with LASSO regularization was used to perform survival analysis. Internal and external validation used a 38-patient training cohort and an 11-patient validation cohort. Statistical significance was set at p < 0.05. Results: Age and six radiomic features (shape and first and second order) from T1W, diffusion, and perfusion maps contributed to the final model. Findings suggest that a small necrotic subregion, inhomogeneous vascularization in the solid non-enhancing subregion, and edema-related tissue damage in the enhancing and edema subregions are linked to poor survival. The model's C-Index was 0.66 (95% C.I. 0.54-0.80). External validation demonstrated good accuracy (AUC > 0.65) at all time points. Conclusions: Radiomics analysis, utilizing segmented perfusion and diffusion maps, provide predictive indicators of survival in IDH wild-type glioblastoma patients, revealing associations with microstructural and vascular heterogeneity in the tumor.

Pseudoexfoliation syndrome without glaucoma: White matter abnormalities detected by conventional MRI and diffusion tensor imaging.

PURPOSE: To assess macro- and microstructural brain changes in patients with pseudoexfoliation syndrome (PXS). MATERIALS AND METHODS: Comprehensive ophthalmic examination and brain MRI were conducted on 20 patients with PXS without glaucoma (aged 62.75 ±â€¯0.4 years) and 20 controls (aged 62 ±â€¯0.6 years). White matter (WM) integrity was evaluated on FLAIR and single-shot multisection SE-EPI diffusion tensor imaging (DTI) sequences. The presence and the number of white matter hyperintensities (WMHIs) on FLAIR images was compared between all patients and control subjects. Microstructural WM changes on DTI was evaluated using Tract-based spatial statistics (TBSS). DTI metrics of the optic tracts were assessed by the region-of-interest (ROI) method. RESULTS: A significantly higher number of WMHIs was found in the patients with PXS than in the control subjects (P ≤ 0.002). On DTI the patients showed bilateral increase in the mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) values in the anterior thalamic radiation, the inferior fronto-occipital fasciculus, the superior longitudinal fasciculus, the inferior longitudinal fasciculus and the forceps minor. TBSS revealed no significant difference in fractional anisotropy (FA) values, but ROIs analysis of the optic tracts revealed decreased FA values in the patients. CONCLUSION: MRI in patients with PXS detects abnormalities in the brain and the optic tracts at a subclinical stage. Early detection of microstructural changes could be useful to guide appropriate treatment to impede the disease process.

The association between multiple sclerosis and spondylosis: When and why.

OBJECTIVES: To evaluate risk factors for the development of cervical spine spondylosis (CSS) in patients with multiple sclerosis (MS) and to propose a pathogenetic mechanism. METHODS: Forty-two consecutive patients aged 23-66 years with MS and 42 age and sex matched controls were evaluated retrospectively; Clinical disability was evaluated with the expanded disability status scale (EDSS) and spasticity with the Asworth score. Total brain lesion volume (BLV), total grey matter (GM) volume and deep GM volume were assessed. In the cervical spine CSS indices (disk dehydration, disk protrusion, abnormal posture and osteophytosis) and the spinal cord lesion load (SLL) was evaluated. The association of CSS indices with the presence of MS, the clinical scales and the brain and spinal cord imaging measurements were assessed. RESULTS: Presence of MS was positively associated with abnormal posture (P=0.002), disk dehydration at C6-C7 (P=0.049) and posterior disk protrusion at C5-C6 (P=0.033) and C6-C7 (P=0.001). All patients had spasticity. Patients with abnormal posture were younger (37.5±11.1years) than those with normal (45.4±8.6years), P=0.024. Age (P=0.008), EDSS (P=0.045) and BLV (P=0.084) were significant independent predictors of abnormal posture. Younger age combined with worse EDSS and increased BLV predicted abnormal posture. CONCLUSIONS: Patients with MS present more frequently spondylosis which is associated with younger age, more severe disability and extensive lesions in the brain. Spasticity induced by the brain lesions and abnormal expression of extracellular matrix proteins in the brain and the intervertebral disk constitute a possible pathogenetic mechanism.

Correlation of diffusion tensor and dynamic susceptibility contrast MRI with DNA ploidy and cell cycle analysis of gliomas.

OBJECTIVES: Flow cytometry provides a powerful tool to assess cells in G0/G1, S and G2/M phase and ploidy. The purpose of the present study was to investigate the correlation between diffusion tensor (DTI) and dynamic susceptibility contrast (DSC) MRI metrics with cell cycle analysis findings in gliomas. PATIENTS AND METHODS: We studied thirty patients who were operated on for glioma. DTI and DSC MRI were performed within a week prior to surgical excision. Lesion/normal ratios were calculated for the ADC, FA and rCBV. In an excised tumour sample flow cytometric analysis was performed. RESULTS: There were 24 glioblastomas, 2 anaplastic astrocytomas, 1 oligoastrocytoma and 3 diffuse astrocytomas. There were significant differences between low and high-grade gliomas for rCBV and ADC values. Low grade tumours had higher G0/G1 phase fraction and lower S-phase, G2/M, S+G2/M and S+G2/M/G0/G1 fractions There was a significant negative correlation between rCBV and G0/G1 phase fraction and a positive correlation with G2/M, S+G2/M and the S+G2/M/G0/G1 fraction. Significant correlation was also observed between FA ratio and S+G2/M/G0/G1. There was a negative significant correlation between ADC and S+G2/M and the S+G2/M/G0/G1 fraction. There were 21 (70%) diploid and 9 (30%) aneuploid tumours. No significant difference was found between diploid and aneuploid tumours with respect to rCBV, ADC and FA values. CONCLUSION: Dynamic susceptibility contrast MRI and diffusion tensor imaging metrics are correlated to tumour aggressiveness as assessed by cell cycle analysis.