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.

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 Parkinson's 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.

Brain involvement in patients with inflammatory bowel disease: a voxel-based morphometry and diffusion tensor imaging study.

OBJECTIVES: To investigate structural brain changes in inflammatory bowel disease (IBD). METHODS: Brain magnetic resonance imaging (MRI) was performed on 18 IBD patients (aged 45.16 ± 14.71 years) and 20 aged-matched control subjects. The imaging protocol consisted of a sagittal-FLAIR, a T1-weighted high-resolution three-dimensional spoiled gradient-echo sequence, and a multisession spin-echo echo-planar diffusion-weighted sequence. Differences between patients and controls in brain volume and diffusion indices were evaluated using the voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) methods, respectively. The presence of white-matter hyperintensities (WMHIs) was evaluated on FLAIR images. RESULTS: VBM revealed decreased grey matter (GM) volume in patients in the fusiform and the inferior temporal gyrus bilaterally, the right precentral gyrus, the right supplementary motor area, the right middle frontal gyrus and the left superior parietal gyrus (p < 0.05). TBSS showed decreased axial diffusivity (AD) in the right corticospinal tract and the right superior longitudinal fasciculus in patients compared with controls. A larger number of WMHIs was observed in patients (p < 0.05). CONCLUSIONS: Patients with IBD show an increase in WMHIs and GM atrophy, probably related to cerebral vasculitis and ischaemia. Decreased AD in major white matter tracts could be a secondary phenomenon, representing Wallerian degeneration. KEY POINTS: • There is evidence of central nervous system involvement in IBD. • Diffusion tensor imaging detects microstructural brain abnormalities in IBD. • Voxel based morphometry reveals brain atrophy in IBD.

Body growth and brain development in premature babies: an MRI study.

BACKGROUND: Prematurity and intrauterine growth restriction are associated with neurodevelopmental disabilities. OBJECTIVE: To assess the relationship between growth status and regional brain volume (rBV) and white matter microstructure in premature babies at around term-equivalent age. MATERIALS AND METHODS: Premature infants (n= 27) of gestational age (GA): 29.8 ± 2.1 weeks, with normal brain MRI scans were studied at corrected age: 41.2 ± 1.4 weeks. The infants were divided into three groups: 1) appropriate for GA at birth and at the time of MRI (AGA), 2) small for GA at birth with catch-up growth at the time of MRI (SGAa) and 3) small for GA at birth with failure of catch-up growth at the time of MRI (SGAb). The T1-weighted images were segmented into 90 rBVs using the SPM8/IBASPM and differences among groups were assessed. Fractional anisotropy (FA) was measured bilaterally in 15 fiber tracts and its relationship to GA and somatometric measurements was explored. RESULTS: Lower rBV was observed in SGAb in superior and anterior brain areas. A positive correlation was demonstrated between FA and head circumference and body weight. Body weight was the only significant predictor for FA (P< 0.05). CONCLUSION: In premature babies, catch-up growth is associated with regional brain volume catch-up at around term-equivalent age, starting from the brain areas maturing first. Body weight seems to be a strong predictor associated with WM microstructure in brain areas related to attention, language, cognition, memory and executing functioning.

CNS involvement in primary Sjogren 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.

Periventricular leukomalacia in preterm children: assessment of grey and white matter and cerebrospinal fluid changes by MRI.

BACKGROUND: Brain plasticity in patients with periventricular leukomalacia (PVL) may suggest grey matter (GM) changes. OBJECTIVE: To assess the volume of 116 GM areas and total volume of GM, white matter (WM) and cerebrospinal fluid (CSF) in preterm children with PVL, using the Statistical Parametric Mapping (SPM5) and the Individual Brain Atlases Statistical Parametric Mapping (IBASPM) toolboxes. MATERIALS AND METHODS: Ten preterm children (gestational age 31.7 +/- 4.2 weeks, corrected age 27.8 +/- 21.7 months) with PVL and 46 matched, preterm control subjects were studied using a three-dimensional T1-weighted sequence. Volumes were calculated using SPM5 and IBASPM. RESULTS: GM volume in frontal superior orbital, posterior cingulum and lingual gyrus, the putamen and thalamus was significantly higher in children with PVL (3.6 +/- 0.6 cm(3), 2.0 +/- 0.5 cm(3), 9.7 +/- 1.7 cm(3), 2.5 +/- 0.6 cm(3), 2.6 +/- 0.9 cm(3), respectively) than in controls (3.1 +/- 0.7 cm(3), 1.5 +/- 0.2 cm(3), 8.2 +/- 1.3 cm(3), 1.7 +/- 1.4 cm(3), 1.8 +/- 0.4 cm(3), respectively). White matter volume was lower (182.1 +/- 40.5 cm(3)) and CSF volume was higher (300.8 +/- 56.2 cm(3)) in children with PVL than in controls (222.9 +/- 67.2 cm(3), 219.0 +/- 61.8 cm(3), respectively), P < 0.05. No significant difference was found in the total GM volume and the volume of neocortex. CONCLUSION: Preterm children with PVL show regional GM volume increase, possibly explained by axonal sprouting, neuronal hypertrophy and neurogenesis, which in turn may reflect brain plasticity.

Voxel-based morphometry and Voxel-based relaxometry in parkinsonian variant of multiple system atrophy.

BACKGROUND AND PURPOSE: 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. METHODS: Using biological parametric mapping the effect of brain atrophy was evaluated in T2 relaxation time (T2) measurements by applying analysis of covariance (ANCOVA) and correlation analysis to the VBM and VBR data. Eleven patients with MSA-P (aged 61.9 +/- 11.7 years, disease duration 5.42 +/- 2.5 years) and 11 controls were studied. RESULTS: In comparison to the controls the patients showed decreased gray matter in the putamen, the caudate nuclei, the thalami, the anterior cerebellar lobes, and the cerebral cortex, and white matter atrophy in the pons, midbrain, and peduncles. VBR analysis showed prolonged T2 in various cortical regions. On ANCOVA, when controlling for gray and white matter volume, these regions of prolonged T2 were shrunk. Negative correlation was demonstrated between T2 and gray and white matter volume. CONCLUSIONS: Diffuse brain atrophy, mainly in the motor circuitry is observed in MSA-P. Normalization for atrophy should always be performed in T2 measurements.