[Show abstract][Hide abstract] ABSTRACT: Spina bifida cystica (SBC) is a group of neurodevelopmental defects caused by improper neural tube closure, which may be responsible for deficits in cognitive functions. The purpose of this study was to examine changes in normal appearing deep gray and white matter brain regions in SBC patients compared with controls through diffusion tensor imaging (DTI) and correlate these changes with neuropsychometric tests.
Conventional magnetic resonance imaging and neuropsychometric tests were performed on 13 patients and ten controls. DTI-derived fractional anisotropy (FA) and mean diffusivity (MD) were quantified in different brain regions in controls and patients.
Significantly decreased FA was observed in caudate nuclei, putamen, genu, splenium, and increased FA was found in middle cerebellar peduncle (MCP) in patients compared with controls. We observed significantly increased MD in genu and splenium. However, increased MD was found in fornix of patients compared with controls. Majority of neuropsychological tests were found to be significantly impaired and some of these showed significant correlation with DTI metrics in genu, splenium, and MCP in these patients.
We conclude that DTI metrics are significantly abnormal in deep gray matter nuclei, genu, splenium, and MCP in SBC patients and may provide microstructural basis for neuropsychological abnormalities in these patients.
Full-text · Article · Nov 2010 · Child s Nervous System
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to use diffusion tensor imaging (DTI) to identify differences in the maturation of deep gray matter (GM) and white matter (WM) between patients with spina bifida cystica (SBC) (n=29) with normal-appearing brains on conventional MRI, and age-matched and sex-matched healthy control participants (n=33). Changes in DTI metrics were calculated using a log-linear regression model. We observed increasing fractional anisotropy (FA) with age in the occipital, fornix, cingulum and middle cerebellar peduncles and decreasing FA with age in the genu and splenium of the corpus callosum (CC) and caudate nuclei in patients compared to controls. Increasing FA values in some of the WM structures probably represent faulty WM maturation, whereas decreasing FA values in the CC represents changes secondary to the affected WM fibers contributing to the CC. DTI changes in deep GM and WM in the absence of any abnormality on conventional MRI might provide the basis for cognitive decline in these patients.
[Show abstract][Hide abstract] ABSTRACT: Region of interest based morphometric diffusion tensor imaging analysis, has been used extensively for the assessment of age-related changes in human brain, is limited to two dimensions and does not reflect the whole fiber bundle; however, diffusion tensor tractography (DTT) offers an overall view of individual fiber bundle in three-dimensional spaces. Quantitative DTT was performed on 51 healthy subjects of pediatric age range and young adults to compare age-related fractional anisotropy (FA) changes in corpus callosum, sensory and motor pathways, limbic tracts [cingulum (CNG) and fornix (Fx)], and superior and inferior longitudinal fascicules. In corpus callosum, inferior longitudinal fascicules, limbic tracts (CNG and Fx), sensory pathways, and motor pathways, an initial sharp increase in FA was observed up to the age of 2 y followed by a gradual increase up to 21 y. In superior longitudinal fascicules, sharp increase in FA was observed up to 3 y followed by a gradual increase. The FA value of the left CNG (p = 0.01, sign test) was observed to be significantly greater than that of the right CNG. We conclude that white matter fiber tracts mature with age and can be assessed by using DTT that may greatly improve our understanding of the human brain development.
Full-text · Article · Sep 2009 · Pediatric Research
[Show abstract][Hide abstract] ABSTRACT: Transient early cerebral laminar organization resulting from normal developmental events has been revealed in human beings through histology and imaging studies. DTI studies have postulated that the fractional anisotropy (FA)-based differentiation of different laminar structures reflects both differing cellular density over the glial fibers and fiber alignment in respective regions. The aim of this study was to correlate FA values in these transient zones with histology. Brain DTI was performed on 50 freshly aborted human fetuses with gestational ages (GA) ranging from 12 to 42 weeks. Regions of interest were placed on the cortical plate, subplate, intermediate and germinal matrix (GMx) zones of the frontal lobe to quantify FA values. Glial fibrillary acidic protein (GFAP), neurofilament (NF) and neuron-specific enolase (NSE) immunohistochemical analyses were performed for the cortical plate, intermediate zone and GMx. In the cortical plate, a significant positive correlation was observed between FA values and percentage area of GFAP expression in fetuses <or=28 weeks of GA (r = 0.56, p = 0.01). FA values showed a significant positive correlation with the percentage area of NF expression in the intermediate zone (r = 0.54, p = 0.05). A significant positive correlation was also observed between FA and the number of NSE-positive cells per mm(2) in the GMx (r = 0.76, p < 0.01) and subplate (r = 0.59, p = 0.03) zones. The results of our study suggest that the FA can be used as noninvasive marker of neurodevelopmental events in the frontal lobe of human fetal brain.
No preview · Article · Aug 2009 · Developmental Neuroscience
[Show abstract][Hide abstract] ABSTRACT: To compare changes in apparent diffusion coefficient (ADC) in neonatal meningitis using serial diffusion-weighted imaging (DWI).
Thirty neonates with meningitis and 12 age/sex-matched controls were studied using DWI. ADC was quantified by placing region of interest(s) on periventricular white matter during acute illness and again at 21 days. Three groups of patients were studied: those with normal findings on both conventional MRI and DWI, those with abnormal DWI only and those with abnormal conventional MRI as well as DWI. Neurodevelopment assessment was performed in controls and patients at 3 months using Indian adaptation of Bayley scales of infant development (BSID) kit.
Patients with neonatal meningitis with normal imaging (n = 8) showed no significant difference in ADC compared to controls. Patients showing abnormality only on DWI (n = 10) and on both conventional magnetic resonance imaging (MRI) as well as DWI (n = 12) had significantly reduced ADC (p = 0.001) than controls at baseline study. Follow-up study showed no significant differences in ADC in controls compared to any patient group. Significantly reduced neurodevelopmental scores were observed in patient groups compared to controls.
We conclude that quantitative ADC may detect meningitis-induced hypoxia early in brain parenchyma, which may be associated with abnormal motor and mental development.
No preview · Article · Jun 2009 · Acta Paediatrica
[Show abstract][Hide abstract] ABSTRACT: In this study, diffusion tensor imaging (DTI) and glial fibrillary acidic protein (GFAP) immunohistochemical analysis in different cortical regions in fetal brains at different gestational age (GA) were performed.
DTI was performed on 50 freshly aborted fetal brains with GA ranging from 12 to 42 weeks to compare age-related fractional anisotropy (FA) changes in different cerebral cortical regions that include frontal, parietal, occipital, and temporal lobes at the level of thalami. GFAP immunostaining was performed and the percentage of GFAP-positive areas was quantified.
The cortical FA values in the frontal lobe peaked at around 26 weeks of GA, occipital and temporal lobes at around 20 weeks, and parietal lobe at around 23 weeks. A significant, but modest, positive correlation (r = 0.31, p = 0.02) was observed between cortical FA values and percentage area of GFAP expression in cortical region around the time period during which the migrational events are at its peak, i.e., GA < or = 28 weeks for frontal cortical region and GA < or = 22 weeks for rest of the lobes.
The DTI-derived FA quantification with its GFAP immunohistologic correlation in cortical regions of the various lobes of the cerebral hemispheres supports region-specific migrational and maturational events in human fetal brain.
[Show abstract][Hide abstract] ABSTRACT: Introduction In this study, diffusion tensor imaging (DTI) and glial fibrillary acidic protein (GFAP) immunohistochemical analysis in different
cortical regions in fetal brains at different gestational age (GA) were performed.
Methods DTI was performed on 50 freshly aborted fetal brains with GA ranging from 12 to 42 weeks to compare age-related fractional
anisotropy (FA) changes in different cerebral cortical regions that include frontal, parietal, occipital, and temporal lobes
at the level of thalami. GFAP immunostaining was performed and the percentage of GFAP-positive areas was quantified.
Results The cortical FA values in the frontal lobe peaked at around 26 weeks of GA, occipital and temporal lobes at around 20 weeks,
and parietal lobe at around 23 weeks. A significant, but modest, positive correlation (r = 0.31, p = 0.02) was observed between cortical FA values and percentage area of GFAP expression in cortical region around the time
period during which the migrational events are at its peak, i.e., GA ≤ 28 weeks for frontal cortical region and GA ≤ 22 weeks
for rest of the lobes.
Conclusions The DTI-derived FA quantification with its GFAP immunohistologic correlation in cortical regions of the various lobes of the
cerebral hemispheres supports region-specific migrational and maturational events in human fetal brain.
[Show abstract][Hide abstract] ABSTRACT: It has been previously hypothesized that the high fractional anisotropy (FA) values in leptomeningeal cortical subcortical white matter (LCSWM) regions of neonatal brain with bacterial meningitis is due to the presence of adhesion molecules in the subarachnoid space, which are responsible for adherence of inflammatory cells over the subarachnoid membrane. The aim of this study was to look for any relationship between FA values in LCSWM regions and various neuroinflammatory molecules (NMs) in cerebrospinal fluid (CSF) measured in neonates with bacterial meningitis. Diffusion tensor imaging was performed on 18 term neonates (median age, 10.5 days) having bacterial meningitis and 10 age-/sex-matched healthy controls. CSF enzyme-linked immunosorbent assay was performed to quantify NMs [soluble intracellular adhesion molecules (sICAM), tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta)]. Significantly increased FA values were observed in LCSWM regions of the patients compared to controls. A significant positive correlation was observed between FA values in LCSWM regions and NMs [sICAM (r=0.67, P=.006), TNF-alpha (r=0.69, P=.005) and IL-1beta (r=0.82, P=.000)] in CSF of these patients. No difference in FA values (P=.99) in LCSWM regions was observed between patients with sterile (0.12+/-0.02) and culture-positive CSF study (0.12+/-0.02). FA may be used as noninvasive surrogate marker of NMs in neonatal meningitis in assessing therapeutic response in future.
Full-text · Article · Sep 2008 · Magnetic Resonance Imaging
[Show abstract][Hide abstract] ABSTRACT: Diffusion tensor imaging was performed on 24 freshly aborted human fetuses with gestational age ranging from 20 to 37 weeks to observe age-related fractional anisotropy changes in cerebellar cortex and cerebellar white matter. Quantitative immunohistochemical analysis was performed for glial fibrillary acidic protein in each fetus molecular layer of cerebellar cortex and myelin basic protein expression was quantified in myelinated areas of the middle cerebellar peduncles. The cerebellar cortical fractional anisotropy reached its peak value at 28 weeks, and then decreased gradually until 37 weeks. The time course of glial fibrillary acidic protein expression paralleled that of fractional anisotropy in the cerebellar cortex from 20 weeks of gestation upto the gestational age at which the fractional anisotropy reached its peak value (28 weeks). In the middle cerebellar peduncles, the fractional anisotropy increased continuously upto 37 weeks of gestational age and showed a significant positive correlation with myelin basic protein immunostained fibers. The fractional anisotropy quantification can be used to assess the migrational and maturation changes during the development of the human fetal cerebellum supported by the immunohistochemical analysis.
No preview · Article · Aug 2008 · International Journal of Developmental Neuroscience
[Show abstract][Hide abstract] ABSTRACT: Age-dependent changes in the normal cerebral white matter have been reported; however, there is no study on normal cerebellar white matter maturation in developing brain using diffusion tensor imaging (DTI). We performed DTI in 21 children who had normal neurological assessment along with no evidence of any abnormality on imaging. The aim of this study was to compare the age-related changes in fractional anisotropy (FA) and mean diffusivity (MD) quantified from cerebral white matter (splenium and genu of the corpus callosum and posterior limb of the internal capsule) and cerebellar white matter (middle cerebellar peduncles, superior cerebellar peduncles, and inferior cerebellar peduncles) regions in healthy children ranging in age from birth to 132 months. Log-linear regression model showed best fit to describe the age-related changes in FA and MD both for cerebral and cerebellar white matter. In cerebral white matter, an initial sharp increase in FA was observed up to the age of 24 months followed by a gradual increase up to 132 months. In cerebellar white matter, sharp increase in FA was observed up to 36 months, which then followed a gradual increase. However, MD showed a sharp decrease in cerebral white matter up to 24 months followed by a more gradual decrease thereafter, while in cerebellar white matter after an initial decrease (6 months), it followed a stable pattern. This study provides normative database of brain white matter development from neonates to childhood. This quantitative information may be useful for assessing brain maturation in patients with developmental delay of the cerebral and cerebellar white matter.
[Show abstract][Hide abstract] ABSTRACT: Neonatal meningitis is one of the important causes of infant mortality and morbidity. Periventricular white matter of neonatal brain is known to be vulnerable to oxidative and hypoxic/ischemic injury secondary to neuro-infections. The aim of this study was to assess periventricular white matter damage in neonatal bacterial meningitis using diffusion tensor imaging (DTI). DTI was performed in 7 age/sex matched controls and 14 neonates with proven bacterial meningitis at the time of diagnosis and after 3 weeks of antibiotic treatment. Region of interest were placed on periventricular white matter to quantify fractional anisotropy (FA) and mean diffusivity (MD). Based on the clinical prognosis and conventional MRI, patients were grouped into those with normal and with abnormal outcome. Compared to controls significantly decreased FA values were observed in entire periventricular white matter except for left parietal white matter in patients with abnormal outcome. Even in those with normal outcome significant decrease in FA values were observed in right parietal and bilateral occipital white matter compared to controls. Decreased FA values in the periventricular white matter regions in neonatal meningitis confirm microstructural white matter injury.
No preview · Article · Jun 2008 · Brain and Development
[Show abstract][Hide abstract] ABSTRACT: This report is to present and discuss an extremely rare association of situs inversus with duodenal atresia in an 11-day-old male neonate born full term and weighing 1.9 kg. The baby presented with recurrent bilious vomiting. Babygram revealed situs inversus and duodenal obstruction. Echocardiography showed dextrocardia with a small ASD. Exploration confirmed a duodenal diaphragm with a central perforation between the third and fourth part of the duodenum and situs inversus. The literature search revealed 20 cases reported so far.
No preview · Article · Apr 2008 · Journal of Indian Association of Pediatric Surgeons
[Show abstract][Hide abstract] ABSTRACT: Increased anisotropy in brain abscesses has been shown to be due to adhesion of inflammatory cells and is suggestive of an active inflammatory process. The objective of this study was to determine if similar changes occur in the pia-arachnoid on the surface of the cerebral cortex in patients with pyogenic meningitis, and if these changes regress following antibiotic therapy.
Diffusion tensor imaging (DTI) was performed on 14 term neonates (mean age 13 days) with bacterial meningitis and 10 healthy age- and sex-matched controls. Regions of interest (ROIs) were placed on areas including the leptomeninges, the cerebral cortex and adjoining subcortical white matter for quantitation of mean fractional anisotropy (FA) and diffusivity (MD) values. Follow-up MRI was performed in five of the neonates in the patient group after 2 weeks of antibiotic treatment. FA and MD values were compared in patients before and after antibiotic treatment as well as with those in the healthy controls.
Significantly higher FA values but no difference in MD values were observed in the patient group as compared to the healthy controls at both time points (before and after antibiotic treatment). Significantly decreased FA values in the frontal, occipital and temporal cortical regions were observed in patients following antibiotic treatment.
DTI-derived FA may be of value in the noninvasive assessment of meningeal inflammatory activity and treatment response in neonates.
[Show abstract][Hide abstract] ABSTRACT: Complete cerebellar agenesis is a very rare entity, which occurs during the early period of embryogenesis and is usually associated with severe motor dysfunction. We report a case of complete cerebellar agenesis with complete corpus callosum agenesis diagnosed on magnetic resonance imaging (MRI). These anomalies were also associated with rudimentary pons.
No preview · Article · Feb 2007 · Pediatric Neurosurgery
[Show abstract][Hide abstract] ABSTRACT: To determine the altered pattern of fractional anisotropy (FA) and mean diffusivity (MD) change in brain parenchyma in serially studied neonates with mild or moderate hypoxic ischemic injury (HIE) within 7 days after birth and again at the age of three months.
Serial diffusion tensor imaging (DTI) was performed at two-time points in term neonates with mild (n = 7) and moderate (n = 10) HIE and age/sex-matched controls (n = 7). Neurodevelopmental outcome was assessed at the time of the 2nd study.
On comparing FA and MD changes over time using two-way analysis of variance between neonates with HIE and controls, we observed significant differences in age-related FA increase (p < 0.05) in anterior limb of internal capsule and periventricular white matter of parietal, occipital, and temporal lobes. Significant differences in age-related MD decrease (p < 0.05) was observed in the caudate nuclei, and temporal white matter among these groups. Significant positive correlation was observed between neurodevelopmental outcome and FA.
The results suggest that abnormal FA and MD values help in early and more accurate assessment of microstructural damage in HIE that may have predictive value for long-term neurofunctional outcome in these neonates.
[Show abstract][Hide abstract] ABSTRACT: A number of studies have suggested the potential utility of in vivo proton MR spectroscopy for the evaluation of brain injury in the asphyxiated neonates. We present our initial experience with in vivo proton MR spectroscopy in neonates who were diagnosed as having hypoxic injury on clinical examination and the severity of the insult was graded using Sarnat staging.
MR imaging and in vivo proton MR spectroscopy was performed in 16 neonates with hypoxic ischemic encephalopathy (HIE) to correlate the imaging and metabolite abnormality with clinical severity of the condition at the time of insult and with outcome at 2 months of age. The ratios of different metabolites were calculated as observed on MR spectroscopy from an 8 ml voxel that included thalami, basal ganglia and part of the ventricular system using spin echo technique with an echo time of 135 ms.
The results of the spectroscopy were compared with imaging abnormalities and Sarnat's clinical staging of HIE. MR Imaging abnormalities included basal ganglia, thalamic and periventricular hemorrhage and periventricular hyperintensities and were noticed in 8/16 neonates with different stages of HIE. Maximum imaging abnormalities were noted in stage II (6/9) followed by stage III (1/2) and stage I (1/5), respectively. The alpha-Glx resonance at 3.76 ppm was seen in 14/16, Glycine at 3.56 ppm (Gly) was seen in 10/16 and Lactate (L) at 1.33 ppm was observed in 4/16 neonates with HIE.
MR spectroscopy was more sensitive than imaging in detecting the insult due to HIE and increased concentration of alpha-Glx/Cr and Gly/Cr correlated better with severity of the HIE. The demonstration of L was associated with poor outcome.
No preview · Article · Aug 2002 · European Journal of Radiology