A combined tract-based spatial statistics and voxel-based morphometry study of the first MRI scan after diagnosis of amyotrophic lateral sclerosis with subgroup analysis.

BACKGROUND AND PURPOSE: This study aims to compare the cortical and subcortical deep gray matter (GM) and white matter (WM) of ALS subjects and controls and to compare ALS subjects with (ALScog) and without (ALSnon-cog) cognitive impairment. MATERIALS AND METHODS: The study was performed in 30 ALS subjects, and 19 healthy controls. Structural T1- and diffusion-weighted MRI data were analyzed using voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS). RESULTS: All DTI measures and GM volume differed significantly between ALS subjects and controls. Compared to controls, greater DTI changes were present in ALScog than ALSnon-cog subjects. GM results showed reduction in the caudate nucleus volume in ALScog subjects compared to ALSnon-cog. and comparing all ALS with controls, there were changes on the right side and in a small region in the left middle frontal gyrus. CONCLUSION: This combined DTI and VBM study showed changes in motor and extra-motor regions. The DTI changes were more extensive in ALScog than ALSnon-cog subjects. It is likely that the inclusion of ALS subjects with cognitive impairment in previous studies resulted in extra-motor WM abnormalities being reported in ALS subjects.

Network over-connectivity differentiates autism spectrum disorder from other developmental disorders in toddlers: A diffusion MRI study.

Advanced connectivity studies in toddlers with Autism Spectrum Disorder (ASD) are increasing and consistently reporting a disruption of brain connectivity. However, most of these studies compare ASD and typically developing subjects, thus providing little information on the specificity of the abnormalities detected in comparison with other developmental disorders (other-DD). We recruited subjects aged below 36 months who received a clinical diagnosis of Neurodevelopmental Disorder (32 ASD and 16 other-DD including intellectual disability and language disorder) according to DSM-IV TR. Structural and diffusion MRI were acquired to perform whole brain probabilistic and anatomically constrained tractography. Network connectivity matrices were built encoding the number of streamlines (DNUM ) and the tract-averaged fractional anisotropy (DFA ) values connecting each pair of cortical and subcortical regions. Network Based Statistics (NBS) was finally applied on the connectivity matrices to evaluate the network differences between the ASD and other-DD groups. The network differences resulted in an over-connectivity pattern (i.e., higher DNUM and DFA values) in the ASD group with a significance of P < 0.05. No contra-comparison results were found. The over-connectivity pattern in ASD occurred in networks primarily involving the fronto-temporal nodes, known to be crucial for social-skill development and basal ganglia, related to restricted and repetitive behaviours in ASD. To our knowledge, this is the first network-based diffusion study comparing toddlers with ASD and those with other-DD. Results indicate the detection of different connectivity patterns in ASD and other-DD at an age when clinical differential diagnosis is often challenging. Hum Brain Mapp 38:2333-2344, 2017. © 2017 Wiley Periodicals, Inc.

Automating Quantitative Measures of an Established Conventional MRI Scoring System for Preterm-Born Infants Scanned between 29 and 47 Weeks' Postmenstrual Age.

BACKGROUND AND PURPOSE: Conventional MR imaging scoring is a valuable tool for risk stratification and prognostication of outcomes, but manual scoring is time-consuming, operator-dependent, and requires high-level expertise. This study aimed to automate the regional measurements of an established brain MR imaging scoring system for preterm neonates scanned between 29 and 47 weeks' postmenstrual age. MATERIALS AND METHODS: This study used T2WI from the longitudinal Prediction of PREterm Motor Outcomes cohort study and the developing Human Connectome Project. Measures of biparietal width, interhemispheric distance, callosal thickness, transcerebellar diameter, lateral ventricular diameter, and deep gray matter area were extracted manually (Prediction of PREterm Motor Outcomes study only) and automatically. Scans with poor quality, failure of automated analysis, or severe pathology were excluded. Agreement, reliability, and associations between manual and automated measures were assessed and compared against statistics for manual measures. Associations between measures with postmenstrual age, gestational age at birth, and birth weight were examined (Pearson correlation) in both cohorts. RESULTS: A total of 652 MRIs (86%) were suitable for analysis. Automated measures showed good-to-excellent agreement and good reliability with manual measures, except for interhemispheric distance at early MR imaging (scanned between 29 and 35 weeks, postmenstrual age; in line with poor manual reliability) and callosal thickness measures. All measures were positively associated with postmenstrual age (r = 0.11-0.94; R2 = 0.01-0.89). Negative and positive associations were found with gestational age at birth (r = -0.26-0.71; R2 = 0.05-0.52) and birth weight (r = -0.25-0.75; R2 = 0.06-0.56). Automated measures were successfully extracted for 80%-99% of suitable scans. CONCLUSIONS: Measures of brain injury and impaired brain growth can be automatically extracted from neonatal MR imaging, which could assist with clinical reporting.

Validation of an MRI Brain Injury and Growth Scoring System in Very Preterm Infants Scanned at 29- to 35-Week Postmenstrual Age.

BACKGROUND AND PURPOSE: The diagnostic and prognostic potential of brain MR imaging before term-equivalent age is limited until valid MR imaging scoring systems are available. This study aimed to validate an MR imaging scoring system of brain injury and impaired growth for use at 29 to 35 weeks postmenstrual age in infants born at <31 weeks gestational age. MATERIALS AND METHODS: Eighty-three infants in a prospective cohort study underwent early 3T MR imaging between 29 and 35 weeks' postmenstrual age (mean, 32+2 ± 1+3 weeks; 49 males, born at median gestation of 28+4 weeks; range, 23+6-30+6 weeks; mean birthweight, 1068 ± 312 g). Seventy-seven infants had a second MR scan at term-equivalent age (mean, 40+6 ± 1+3 weeks). Structural images were scored using a modified scoring system which generated WM, cortical gray matter, deep gray matter, cerebellar, and global scores. Outcome at 12-months corrected age (mean, 12 months 4 days ± 1+2 weeks) consisted of the Bayley Scales of Infant and Toddler Development, 3rd ed. (Bayley III), and the Neuro-Sensory Motor Developmental Assessment. RESULTS: Early MR imaging global, WM, and deep gray matter scores were negatively associated with Bayley III motor (regression coefficient for global score ß = -1.31; 95% CI, -2.39 to -0.23; P = .02), cognitive (ß = -1.52; 95% CI, -2.39 to -0.65; P < .01) and the Neuro-Sensory Motor Developmental Assessment outcomes (ß = -1.73; 95% CI, -3.19 to -0.28; P = .02). Early MR imaging cerebellar scores were negatively associated with the Neuro-Sensory Motor Developmental Assessment (ß = -5.99; 95% CI, -11.82 to -0.16; P = .04). Results were reconfirmed at term-equivalent-age MR imaging. CONCLUSIONS: This clinically accessible MR imaging scoring system is valid for use at 29 to 35 weeks postmenstrual age in infants born very preterm. It enables identification of infants at risk of adverse outcomes before the current standard of term-equivalent age.

Diffusion Tractography Biomarkers of Pediatric Cerebellar Hypoplasia/Atrophy: Preliminary Results Using Constrained Spherical Deconvolution.

BACKGROUND AND PURPOSE: Advances in MR imaging modeling have improved the feasibility of reconstructing crossing fibers, with increasing benefits in delineating angulated tracts such as cerebellar tracts by using tractography. We hypothesized that constrained spherical deconvolution-based probabilistic tractography could successfully reconstruct cerebellar tracts in children with cerebellar hypoplasia/atrophy and that diffusion scalars of the reconstructed tracts could differentiate pontocerebellar hypoplasia, nonprogressive cerebellar hypoplasia, and progressive cerebellar atrophy. MATERIALS AND METHODS: Fifteen children with cerebellar ataxia and pontocerebellar hypoplasia, nonprogressive cerebellar hypoplasia or progressive cerebellar atrophy and 7 controls were included in this study. Cerebellar and corticospinal tracts were reconstructed by using constrained spherical deconvolution. Scalar measures (fractional anisotropy and mean, axial and radial diffusivity) were calculated. A general linear model was used to determine differences among groups for diffusion MR imaging scalar measures, and post hoc pair-wise comparisons were performed. RESULTS: Cerebellar and corticospinal tracts were successfully reconstructed in all subjects. Significant differences in diffusion MR imaging scalars were found among groups, with fractional anisotropy explaining the highest variability. All groups with cerebellar pathologies showed lower fractional anisotropy compared with controls, with the exception of cerebellar hypoplasia. CONCLUSIONS: This study shows the feasibility of constrained spherical deconvolution to reconstruct cerebellar and corticospinal tracts in children with morphologic cerebellar pathologies. In addition, the preliminary results show the potential utility of quantitative analysis of scalars of the cerebellar white matter tracts in children with cerebellar pathologies such as cerebellar hypoplasia and atrophy. Further studies with larger cohorts of patients are needed to validate the clinical significance of our preliminary results.

Structural hemispheric asymmetries in the human precentral gyrus hand representation.

The superior region of the precentral gyrus (preCG) is known to be actively involved with hand function and has been proposed as a possible neural correlate of handedness. To test this hypothesis, we used a combined voxel-based morphometric (VBM) asymmetry analysis of structural MRI, along with diffusion MRI (dMRI) tractography to investigate laterality indices of corticomotor white matter (WM) pathways, based on measures of fractional anisotropy (FA). The relationship between measures of motor performance and FA laterality indices was also investigated. In a cohort of 14 right-handed healthy participants, the VBM asymmetry analysis revealed an area within the preCG associated with hand representation. The tractography analysis revealed that this region possessed a number of major WM intrahemispheric connections to the brain stem, thalamus, cerebellum, postcentral, caudal middle and superior frontal, and superior and inferior parietal corticomotor regions. Within the corticospinal tracts, we found FA was significantly higher in the left hemisphere compared with the right. Furthermore, significant correlations were found between FA asymmetry measures projecting from this region, namely corticospinal tracts and those connecting the postcentral gyri, with grip strength and finger-tapping performance, respectively. A number of the motor pathways projecting from this region also exhibited leftward asymmetry of FA distributions. The findings from this study highlight the role of the left motor cortex in skilled motor performance and provide a framework for the study of the relationship between handedness and preCG hand representation in larger normative populations.

Distinguishing recurrent primary brain tumor from radiation injury: a preliminary study using a susceptibility-weighted MR imaging-guided apparent diffusion coefficient analysis strategy.

BACKGROUND AND PURPOSE: The accurate delineation of tumor recurrence presents a significant problem in neuro-oncology. Our aim was to improve the identification of brain tumor recurrence from chemoradiation injury by using CE-SWI, a technique that provides improved visualization of the heterogeneous patterns of brain tumor pathology, to guide the analysis of ADC measures within the peritumoral territory. MATERIALS AND METHODS: Seventeen patients who were being treated for high-grade glial neoplasms took part in the study. All patients presented with new enhancing lesions on follow-up CE-T1. Recurrence or chemoradiation injury was confirmed from either histologic analysis or extensive clinical follow-up. Regions of enhancement on registered CE-SWI and CE-T1 images were extracted in a semiautomated fashion and transferred to co-registered ADC maps. Significant differences in ADC measures defined within the enhancement volumes on serial MR images were analyzed by using a nonparametric Kolmogorov-Smirnov approach and correlated with clinical follow-up diagnoses. RESULTS: Analysis of the serial data revealed that patients with a diagnosis of tumor recurrence had significantly reduced ADC measures within the enhancement volume delineated on CE-SWI. In contrast, patients with SD had significantly elevated ADC within the CE-SWI enhancement volume. CONCLUSIONS: The findings of an increase in enhancement volume delineated on serial CE-SWI maps, along with a concomitant reduction in ADC within this volume for patients with recurrent tumor, provide support for such an approach to be used to assist in follow-up patient management strategies.