Arti Srivastava

Comparative evaluation of corpus callosum DTI metrics in acute mild and moderate traumatic brain injury: Its correlation with neuropsychometric tests

Primary objective: To look for differences in vulnerability of corpus callosum (CC) in patients of mild and moderate traumatic brain injury (TBI) in the acute stage using quantitative diffusion tensor imaging (DTI) and to correlate these with neuropsychometric tests (NPT) done at 6 months post-injury. Research design, methods and procedures: Conventional MRI, DTI and NPT were performed on 83 patients (moderate TBI, n = 57; mild TBI, n = 26) within 5–14 days after TBI. Thirty-three age- and sex-matched healthy controls were also included for comparison. Results: Significantly decreased fractional anisotropy (FA) in genu and splenium; significantly increased radial diffusivity (RD) values in genu, midbody and splenium with significant increase in mean diffusivity (MD) and a decrease in axial diffusivity (AD) only in genu, respectively, in patients with moderate TBI compared to healthy controls were observed. However, in moderate TBI, significantly decreased FA was found only in genu compared to mild TBI. Moderate TBI showed poor NPT scores compared to mild TBI, but this did not reach statistical significance. Conclusions: It is concluded that DTI abnormalities in the regions of CC were more in patients with moderate TBI compared to mild TBI and this was associated with relatively poor neuropsychological outcome 6 months post-injury.

Encephalopathy assessment in children with extra-hepatic portal vein obstruction with MR, psychometry and critical flicker frequency

BACKGROUND & AIMS Mild cognitive and psychomotor deficit has been reported in patients with extra-hepatic portal vein obstruction. This prospective study was done to ascertain the presence of minimal hepatic encephalopathy by neuropsychological testing and its correlation with diffusion tensor imaging derived metrics, T1 signal intensity, brain metabolites in (1)H magnetic resonance spectroscopy, blood ammonia and critical flicker frequency in patients with extra-hepatic portal vein obstruction. METHODS Neuropsychological tests, critical flicker frequency, blood ammonia, diffusion tensor imaging, T1 signal intensity and (1)H magnetic resonance spectroscopy were determined in 22 extra-hepatic portal vein obstruction and 17 healthy children. Bonferroni multiple comparison post hoc analysis was done to compare controls with patient groups. RESULTS Based on neuropsychological tests, 7/22 patients had minimal hepatic encephalopathy, and significantly increased Glx/Cr ratio, blood ammonia, mean diffusivity and globus pallidus T1 signal intensity with decreased critical flicker frequency in comparison to controls and in those without minimal hepatic encephalopathy. Cho/Cr, mI/Cr ratio and fractional anisotropy were unchanged in patient groups compared to controls. A significant inverse correlation of neuropsychological test with mean diffusivity, Glx/Cr ratio and blood ammonia and a positive correlation among mean diffusivity, blood ammonia and Glx/Cr ratio was seen. CONCLUSIONS Extra-hepatic portal vein obstruction is a true hyperammonia model with porto-systemic shunting and normal liver functions that results in minimal hepatic encephalopathy in one-third of these children. Hyperammonia results in generalized low grade cerebral edema and cognitive decline as evidenced by increased Glx/Cr ratio, mean diffusivity values and abnormal neuropsychological tests.

Serial changes in diffusion tensor imaging metrics of corpus callosum in moderate traumatic brain injury patients and their correlation with neuropsychometric tests: a 2-year follow-up study.

ObjectiveTo assess longitudinally the severity of diffuse axonal injury in the corpus callosum in patients with moderate traumatic brain injury (TBI) through quantitative diffusion tensor imaging and to correlate these changes with neuropsychometric tests (NPT) at 6 and 24 months after injury. DesignProspective longitudinal study. ParticipantsSixteen patients with TBI and 17 age/sex-matched healthy controls. MethodsPatients underwent magnetic resonance imaging at 3 time points: within 2 weeks (range = 5–14 days), 6 months, and 24 months after injury. NPT could be performed only at 6 and 24 months. ResultsIn patients with TBI, a significant increase in fractional anisotropy (FA) values in genu as well as an insignificant decrease in radial diffusivity (RD) and mean diffusivity values in genu and splenium were observed over time, respectively. FA, RD, and mean diffusivity values continued to be abnormal in patients compared with controls at the end of 2 years. Although some NPT scores improved over time in these patients, these were still significantly impaired compared with controls. ConclusionsFA and RD indices appear to be surrogate markers of microstructural alterations in patients over time and correlate significantly with some of the NPT scores. The recovery in these indices associated with recovery in neurocognitive deficits suggests that these indices may be used as an objective marker for residual injury in these patients.

Cerebral oedema in minimal hepatic encephalopathy due to extrahepatic portal venous obstruction

Background: Minimal hepatic encephalopathy (MHE) has recently been reported in patients with extrahepatic portal venous obstruction (EHPVO).

Correlation of Diffusion Tensor Imaging Metrics with Neurocognitive Function in Chiari I Malformation

BACKGROUND The aim of this study was to examine changes in normal-appearing deep gray and white matter regions of the brain in patients with Chiari I malformation compared with controls using diffusion tensor imaging (DTI) and to correlate these changes with neuropsychological (NP) test scores. METHODS Conventional magnetic resonance imaging, DTI, and neuropsychological tests were performed on 10 patients (median age 27 years, range 18 to 36 years) with Chiari I malformation and 10 age/sex-matched healthy controls. Diffusion tensor imaging metrics (fractional anisotropy, mean diffusivity [MD], radial diffusivity [RD], and axial diffusivity [AD]) were quantified in different regions of the brain in patients as well as in controls using the region of interest (ROI) method. An independent Student t test was performed to evaluate differences in diffusion tensor imaging metrics from patients and controls. Pearsons correlation coefficient was also used to determine association between NP test scores and DTI metrics in patients. RESULTS Significantly reduced fractional anisotropy with increased MD was found in genu, splenium, fornix, and putamen in patients compared with controls; however, RD significantly increased in fornix and cingulum, whereas AD significantly increased in putamen, thalamus, and fornix as compared with controls. NP tests were found to be abnormal in patients with Chiari I malformation compared with controls, and some of these tests showed significant correlation with DTI metrics. CONCLUSIONS We conclude that abnormal changes in the DTI metrics in patients with Chiari I malformation indicate microstructural abnormalities in different brain regions that may be associated with neurocognitive abnormalities.

Brain MR Imaging and 1H-MR Spectroscopy Changes in Patients with Extrahepatic Portal Vein Obstruction from Early Childhood to Adulthood

BACKGROUND AND PURPOSE: MR imaging and 1H-MR spectroscopy changes are well reported in cirrhotic patients, whereas they are inadequately reported in EHPVO. The aim of this study was to investigate age-related changes in brain MR imaging and metabolite profile in EHPVO with and without MHE and to explore any correlation of imaging and 1H-MR spectroscopy parameters with blood ammonia. MATERIALS AND METHODS: Sixty-three patients with EHPVO (children, 7–12 years [n = 22], adolescents, 13–18 years [n = 15] and adults, 19–41 years [n = 26]) and 47 healthy age/sex-matched volunteers were studied. Neuropsychological tests, MR imaging, 1H-MR spectroscopy, and blood ammonia estimation were performed in all subjects. RESULTS: Of 63 EHPVO patients, 25 (40%) who had MHE showed significantly increased MD, Glx, and blood ammonia in all 3 age groups; however, myo-inositol was significantly lower only in adults when compared with controls. MD positively correlated with blood ammonia and Glx in all age groups. Brain choline levels were normal in all patients with different age groups. CONCLUSIONS: Increases in brain MD, Glx, and blood ammonia were associated with MHE in all age groups. Normal brain choline in EHPVO signifies healthy liver and may serve as a diagnostic marker for its differentiation from cirrhosis-induced encephalopathy. Significant decrease of myo-inositol in adults is probably due to cellular osmoregulation secondary to long-standing hyperammonemia.

Temporal alterations in brain water diffusivity in neonatal meningitis

Aim:  To compare changes in apparent diffusion coefficient (ADC) in neonatal meningitis using serial diffusion‐weighted imaging (DWI).