Loukia C. Tzarouchi

Age-related grey matter changes in preterm infants: An MRI study

Grey matter (GM) maturation has not been previously studied in healthy preterm children. The purpose of this study was to evaluate the age dependency of GM development in 116 GM areas in preterm subjects. Sixty one preterm infants (corrected age: 13.7+/-9.92 months, gestational age: 33.4+/-1.9 weeks) with normal structural appearance on MRI were included in the study. Using a T1-weighted high resolution 3D spoiled gradient echo sequence, volumes of 116 GM areas were calculated after their segmentation using the Voxel Based Morphometry Toolboxes and the Individual Brain Atlas Statistical Parametric Mapping (IBASPM) software packages. Non linear regression analysis assessed age dependency of volume data for every GM area using the monoexponential function y=A-Bexp(-x/C). All supratentorial GM areas followed the monoexponential function model reasonably well. Cerebellar structures had a poor goodness of fit. Volume increase of the individual GM areas followed an inferior to superior and a posterior to anterior pattern. The putamen, thalamus, and caudate nucleus reached 99% of the final volume earlier than most cortical GM areas. The visual cortex and the postcentral and precentral cortices matured earlier than the parietal, frontal and temporal cortices. The fronto-occipital asymmetry or torque seen in adults was observed in the preterm infants; the left occipital areas reached maturation earlier than the right, while the right prefrontal and frontal areas matured earlier than the left. To conclude, GM development progresses in a region-specific manner coinciding with functional, phylogenetical and regional white matter (WM) maturation.

Voxel‐Based Morphometry and Voxel‐Based Relaxometry in Parkinsonian Variant of Multiple System Atrophy

Multiple system atrophy (MSA) is a progressive neurodegenerative disorder divided into a parkinsonian (MSA‐P) and a cerebellar variant. The purpose of this study was to assess regional brain atrophy and iron content using Voxel‐based morphometry (VBM) and Voxel‐based relaxometry (VBR) respectively, in MSA‐P.

CNS Involvement in Primary Sjögren Syndrome: Assessment of Gray and White Matter Changes With MRI and Voxel-Based Morphometry

OBJECTIVE The purpose of this study was to evaluate with MRI the involvement of gray matter and white matter structures in patients with primary Sjögren syndrome. SUBJECTS AND METHODS Fifty-three patients with primary Sjögren syndrome, 18 age- and disease duration-matched patients with systemic sclerosis, and 35 age-matched control subjects were examined for differences in white matter hyperintensities (WMHIs) detected on FLAIR MR images. Differences in brain volume between patients with primary Sjögren syndrome and controls were studied by application of voxel-based morphometry to a 3D T1-weighted sequence. RESULTS WMHIs were observed in 38 of the 53 patients with primary Sjögren syndrome, six of 18 patients with systemic sclerosis, and 17 of 35 controls. The numbers of WMHIs 2 mm or larger and the number smaller than 2 mm were higher in patients with primary Sjögren syndrome than in controls (≥ 2 mm, p = 0.004; < 2 mm, p < 0.001). No significant difference was observed in the number of WMHIs in primary Sjögren syndrome patients and that in systemic sclerosis patients. After control for age, a positive relation was found between disease duration and total number of WMHIs (p = 0.037) and number of WMHIs 2 mm or larger (p = 0.023) in patients with primary Sjögren syndrome. In comparison with the controls, patients with primary Sjögren syndrome had decreased gray matter volume in the cortex, deep gray matter, and cerebellum. Associated loss of white matter volume was observed in areas corresponding to gray matter atrophy and in the corpus callosum (p < 0.05). CONCLUSION Patients with primary Sjögren syndrome have WMHIs and gray and white matter atrophy, probably related to cerebral vasculitis.

Abnormalities of brain neural circuits related to obesity: A Diffusion Tensor Imaging study

PURPOSE Increased Body-Mass-Index (BMI) has been associated with brain atrophy in both gray and white matter structures. However, little is known concerning the integrity of white matter tracts in obesity. The purpose of the study was to evaluate the pattern of changes in white matter microstructure in human adiposity. MATERIAL AND METHODS The study included 268 participants (52 obese, 96 overweight and 120 normal-weight) that were retrospectively evaluated by Diffusion Tensor Imaging. The fractional anisotropy, axial, radial and mean diffusivity values were compared between the above groups using Tract Based Spatial Statistics. RESULTS The analysis revealed that the increased BMI was related with decreased fractional anisotropy in several white matter regions including the anterior and posterior thalamic radiation, the inferior fronto-occipital fasciculus, the inferior and superior longitudinal fasciculus, the corpus callosum (callosal body and forceps minor), the uncinate fasciculus, the internal capsule, the corticospinal tract and the cingulum (cingulate gyrus and hippocampus). CONCLUSIONS Anisotropic diffusion of anatomic regions governing important brain circuits such as reward seeking inhibition, motivation/drive and learning/conditioning decreases with increasing BMI.

Multimodal imaging evaluation of excessive daytime sleepiness in Parkinson's disease

Purpose of the study: The multimodal imaging investigation of excessive daytime sleepiness (EDS) in Parkinsons disease (PD). The role of dopaminergic treatment and other clinical parameters was also evaluated. Materials and methods: Seventeen non-demented PD patients with EDS (PD-EDS) and 17 PD patients without EDS were enrolled. Clinical, treatment and MRI data were acquired. Gray matter (GM) volume was examined with voxel-based morphometry, while white matter (WM) integrity was assessed with diffusion tensor imaging by means of fractional anisotropy, mean diffusivity, axial diffusivity (AD) and radial diffusivity measures. Results: Increased regional GM volume was found in the PD-EDS group bilaterally in the hippocampus and parahippocampal gyri. Increased AD values were also shown in the PD-EDS group, in the left anterior thalamic radiation and the corticospinal tract and bilaterally in the superior corona radiata and the superior longitudinal fasciculus. Levodopa equivalent dose differed significantly between the groups and was the only predictor of EDS, while the only predictor of the Epworth sleepiness scale score in the PD-EDS group was the dopamine-agonist dose. Increased frequency of gamblers was also observed in the PD-EDS group. Conclusions: Regional GM increases and increased AD values in certain WM tracts were found in the PD-EDS group. The changes could result from disinhibited signaling pathways or represent compensatory changes in response to anatomical or functional deficits elsewhere. The study findings support also the contribution of the total dopaminergic load in the development of EDS, while the dose of dopamine agonists was found to predict the severity of the disorder.

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

BackgroundThere is evidence of microstructural changes in normal-appearing white matter of patients with tuberous sclerosis complex.ObjectiveTo evaluate major white matter tracts in children with tuberous sclerosis complex using tract-based spatial statistics diffusion tensor imaging (DTI) analysis.Materials and methodsEight 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.ResultsTract-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.ConclusionPatients with tuberous sclerosis complex have increased axial diffusivity in major white matter tracts, probably related to reduced axonal integrity.

Evidence Suggesting the End of Universal Domestic Asbestos Exposure in Metsovo, NW Greece

Background: Inhabitants of Metsovo, NW Greece, had been domestically exposed to asbestos from a gradually abandoned whitewash (“luto”) that resulted in a declining epidemic of malignant mesothelioma. Objectives: We aimed to evaluate whether other sources of asbestos exposure exist following “luto” abandonment. Methods: Chest computed tomography (CT) and bronchoalveolar lavage (BAL) were used to evaluate residual asbestos exposure in younger Metsovites through the identification of pleural calcifications and asbestos bodies, respectively. In order to provide a historical universally exposed group for comparison, we used the accumulated chest CTs and chest roentgenograms of our previous studies, performed in Metsovites with confirmed exposure but negative chest roentgenogram. As an additional external comparison group, we also assessed CT scans and chest roentgenograms of Metsovites being older than our target group obtained from the records of the Radiology Department between 2009 and 2011. In order to be able to compare our BAL findings, we sought historical controls among BAL studies performed in Metsovites with known exposure to “luto,” in the 1980s-1990s, mainly to evaluate alveolitis. Those belonging to individuals of the same age range were used for further comparison. Results: Twenty-two Metsovites born between 1960 and 1980 consented to undergo a chest CT scan, while another 14 CTs were retrieved from the records of the Radiology Department (among 86 of all ages), thus increasing the number of individuals studied to 36. Five of the 36 Metsovites studied were former “luto” users for a short period of time. Minimal pleural calcifications were present in 2 of them, while all chest CTs of nonusers were negative. All 8 BAL studies were negative for asbestos bodies. Conclusion: “Luto” use seems to have been the only source of considerable asbestos exposure in Metsovo.

High-resolution heavily T2-weighted magnetic resonance imaging for evaluation of the pituitary stalk in children with ectopic neurohypophysis

BackgroundIn anterior pituitary deficiency, patients with non visible pituitary stalk have more often multiple deficiencies and persistent deficiency than patients with visible pituitary stalk.ObjectiveTo compare the diagnostic value of a high-resolution heavily T2-weighted sequence to 1.5-mm-thick unenhanced and contrast-enhanced sagittal T1-weighted sequences to assess the presence of the pituitary stalk in children with ectopic posterior pituitary gland.Materials and methodsWe retrospectively evaluated the MRI data of 14 children diagnosed with ectopic posterior pituitary gland between 2010 and 2014. We evaluated the presence of a pituitary stalk using a sagittal high-resolution heavily T2-weighted sequence and a 1.5-mm sagittal T1-weighted turbo spin-echo sequence before and after contrast medium administration.ResultsA pituitary stalk was present on at least one of the sequences in 10 of the 14 children (71%). T2-weighted sequence depicted the pituitary stalk in all 10 children, whereas the 1.5-mm-thick T1-weighted sequence depicted 2/10 (20%) before contrast injection and 8/10 (80%) after contrast injection (P=0.007).ConclusionCompared with 1.5-mm-thick contrast-enhanced T1-weighted sequences, high-resolution heavily T2-weighted sequence demonstrates better sensitivity in detecting the pituitary stalk in children with ectopic posterior pituitary gland, suggesting that contrast injection is unnecessary to assess the presence of a pituitary stalk in this setting.