Tuesday, May 21, 2019

Research

With acquisition of multiple state of art equipment in last couple of years has thrown open opportunity for doing good academic and research activities. Despite being a very small department with only seven member’s decent amount of research activities have been undertaken in last few years. Department has one 3T MRI scanner exclusively for research activities. Faculty of the department is involved in carrying out multiple research projects in collaboration with other clinical departments.

Broad areas of research activities include

Dementia:structural and functional connectivity in alzheimers dementia, Fronto temporal dementia etc. DrJitendersaini is the faculty who is interested in this field

Neuropsychiatric disorders: More than 30 imaging based projects are currently underway using the techniques of Fmri and diffusion weighted imaging in the field of OCD, addiction and schizophrenia.Dr Rose dawn Bharath, DrJitenderSaini and DrChandrajit Prasad has several collaborative projects with facult from department of Psychiatry

Cognition and language: Neurohemodynamic correlates of cognitive networks and the effect of education and normative multilingualism on these networks is being studied using task based fMRI, resting state fMRI and fMRI EEG.DrRose Dawn Bharath is the faculty who is interested in this field

Neurometabolic disease: Application of newer MR imaging techniques for the diagnosis of neurometabolic diseases. Creation of large MRI database of metabolic especially Wilsons disease and mitochondrial cytopathies.DrChandrajit Prasad and Dr Maya D Bhat has several collaborative projects with the department of Neurology

Movement disorders:Investigation in various movement disorders have been carried out. Large sample of spinocerebellar ataxia have been studied previously and aim to carry out further research in these disorders especially on SCA1, 2, 3 and 12. Similar studies in PSP patients with aim to characterize subtypes of PSP using advanced MR techniques. Resting state and motor functional connectivity in writers cramp and its modulations using rTMS has been assessed.Dr Rose Dawn Bharath and DrJitenderSaini has several research projects in this field

Neuroinfections:Serial MR Perfusion markers were used to derive biomarkers that can predict response to treatment.Dr A K Gupta and Dr Rose Dawn Bharath guides students in these topics

Epilepsy: Institute has a dedicated epilepsy team and quantitative imaging studies are being conducted on various epileptic disorders like focal epilepsies, Juvenile myoclonic epilepsy and reflex epilepsy especially hot water epilepsy. Imaging contrasts like diffusion tensor imaging and functional MRI are being used to study these disorders. EEG f-MRI application in various seizure disorders is another area of research.Dr Rose Dawn Bharath and DrJitenderSaini has several research projects in this field

Brain tumors:Brain tumors is another area where research imaging projects are being carried out. In the past studies have been done on proton and phosphorus spectroscopy for characterization of the brain tumors. Current areas of interest are perfusion and diffusion weighted imaging for characterization of various brain tumors. Efforts are being made to study newer perfusion imaging techniques like DCE for characterization of brain tumors. Dr Rose Dawn Bharath currently works on peritumoral imaging genetic correlation and texture based glioma grading, cortical plasticity following glioma surgery,DrJitenderSaini works on ASL perfusion in grading of gliomaandDrChandrajit Prasad works on segmentation approaches on glioma grading.

Demyelinating disorders: Focus on various aspects of acquired inflammatory disorders like multiple sclerosis, neuromyelitisoptica, ADEM etc is carried out in collaboration with the department of Neurology. Dr Rose Dawn Bharath, Dr Maya D Bhat guides students in these fields.

Traumatic brain injury: Research work has commenced in this direction during last few years. In a recently concluded study longitudinal changes in the brain morphology and connectivity using DTI have been studied.Dr Rose Dawn Bharath and DrJitenderSaini has several research projects in this field

Anaesthesia and pain: Small pilot projects have been carried out in the field of anaesthesia and pain imaging. DrJitenderSaini and DrArvinda H R has collaborative projects in this field

Interventional neuroradiology: Research areas include Idiopathic intracranial hypertension, management of direct CCF and spinal vascular malformations.Dr AK Gupta, DrHima S Pendharkar,  DrArvinda HR and DrChandrajit Prasad guides several students in these topics.

 

Research Activities

 

Name of Project/Title

fMRI Correlates of auditory discrimination in Auditory Dys-synchrony

Investigator 

-          Principal investigator

-          Co- Principal investigator

Dr Rose Dawn Bharath

Dr A K Gupta

DrJayaram V

Mr Naveen

Total duration of the project

6 months

Funding Agency (ies)

NIMHANS

Total funding

1.2 lakhs

Funding during the year 2012-13

1.2 lakhs

Status

Completed

Auditory Dys-synchrony: A Voxel-based Morphometry Study

 

Abstract

 

Introduction

Auditory dys-synchrony describes a condition in which a patient’s otoacoustic emissions (OAE) are (or were at one time) present and auditory brainstem responses (ABR) are abnormal or absent. In some instances, it is identified on the basis of present cochlear microphonics (CM) and abnormal or absent ABRs with or without abnormalities of OAEs.

 

Methodology

All subjects were studied using a high resolution anatomical scan of the whole brain acquired in 3.0 Tesla Siemens Skyra MR Scanner  with   20- channel head coil using a three dimensional T1 weighted sagittal magnetisation prepared rapid gradient echo (MP-RAGE) sequence in 192 slices with TR: 1900 ms; TE: 2.44 ms; TI: 900ms; FOV: 250x250; Resolution: 256x256; Slice thickness :1 mm.Voxel based morphometry analysis was done using VBM8 toolbox of SPM8 comparing the group of auditory dys-synchrony patients with the group of healthy controls.

 

Results

Results demonstrated structural brain differences in auditory dys-synchrony patients in areas including right superior temporal gyrus, bilateral anterior cingulate, left cingulate gyrus, left uncus, bilateral inferior frontal gyrus, right precentralgyrus, left middle frontal gyrus, left superior parietal lobule, post central gyrus and  left sub-lobar putamen when compared with healthy controls.

 

Conclusion

Voxel based morphometry group analysis of patients compared with controls revealed significant volumetric changes predominantly involving sensory and motor cortices. This finding could imply cortical plasticity in patients to accommodate for the auditory neuropathy.

 

 

Results of the group analysis rendered over a glass brain representing areas which were seen significantly larger in patients with auditory dysynchrony compared with controls.

 

Name of Project/Title

Generativity in cognitive networks

Investigator 

-          Co- Principal investigator

 

Dr Rose Dawn Bharath

Total duration of the project

3 years

Funding Agency (ies)

DST

Total funding

17 crores

Funding during the year 2012-13

 

Status

Completed

Human memory is an enigmatic component of cognition which many researchers have attempted to comprehend. Accumulating studies on functional connectivity see brain as a complex dynamic unit with positively and negatively correlated networks in perfect coherence during a task. We aimed to examine coherence of network connectivity during visual memory encoding and retrieval in the context of education. School Educated (SE) and College Educated (CE) healthy volunteers (n = 60) were recruited and assessed for visual encoding and retrieval. Functional connectivity using seed to voxel based connectivity analysis of the posterior cingulate cortex (PCC) was evaluated. We noticed that there were reciprocal dynamic changes in both dorsolateral prefrontal cortex (DLPFC) region and PCC regions during working memory encoding and retrieval. In agreement with the previous studies, there were more positively correlated regions during retrieval compared to encoding. The default mode network (DMN) networks showed greater negative correlations during more attentive task of visual encoding. In tune with the recent studies on cognitive reserve we also found that number of years of education was a significant factor influencing working memory connectivity. SE had higher positive correlation to DLPFC region and lower negative correlation to DMN in comparison with CE during encoding and retrieval.

 

 

 

Seed to voxel based connectivity for PCC seed for encoding and retrieval in the context of education. CE encoding (a), CE retrieval (b) SE encoding (c), SE retrieval (d). Red color demonstrating positive correlation with source seed and blue color demonstrating negative correlation with source seed

 

 

Name of Project/Title

Brain Organization in normative multilingualism

Investigator 

-          Co- Principal investigator

 

Dr Rose Dawn Bharath

Total duration of the project

3 Years

Funding Agency (ies)

DST

Total funding

 

Funding during the year 2012-13

 

Status

Completed

 

 

Language is a system of brain circuits. Functional MRI is being increasingly used to understand the dynamics of brain circuits especially language. The study was undertaken to assess the neural systems of language in bilinguals by means of antonym generation in Tamil to Tamil (TT), English to English Language (EE) and code switching between Tamil to English (TE) using functional Magnetic Resonance Imaging (fMRI). Proficient 16 Tamil native speakers from rural Tamilnadu, South India participated in the study.  Tamil (L1) was first language and English (L2) second language. The blood oxygenation level dependent (BOLD) signal showed TT uniquely activated prosody and EE activated semantic processing and visual attention separately. The common areas for both the languages involved higher order cognitive processing like central executive of working memory, error monitoring, cognitive control,subvocal speech, auditory rehearsal, semantic fluency and visual processing. The code switching task TE was mediated by executive processes, cognitive control, visual attention, semantic processing, memory retrieval, emotional processing, visual processing, motor-programming and arousal. Hence the language processing in the brain requires executive processes and cognitive controls.

 

 

Name of Project/Title

The role of T2* perfusion in therapeutic response assessment of CNS tuberculomas

Investigator 

-          Principal investigator

-          Co- Principal investigator

 

DrAnatharam

Dr Rose Dawn Bharath

Total duration of the project

3 years

Funding Agency (ies)

Non funded

Total funding

NA

Funding during the year 2012-13

NA

Status

Completed

We conducted serial functional imaging analysis using T2* perfusion in 19 patients with tuberculoma with an aim of evaluating the role of perfusion parameters in predicting response tostandard treatment with ATT. Our results found that, of the 19 cases of brain tuberculomas evaluated using T2* perfusion,13 cases with high rCBV on initial scan showed clinical and imaging improvement. 6 cases with low rCBV on initial scan did not respond to treatment.

Treatment responders showed statistically significant higher values of rCBV as compared to both non responders and surgically  excised lesions.

 

We conclude that presence of very low rCBV Values on initial scan in a tuberculoma may be the reason for nonresponse to antituberculous therapy and may be an indicator of an early excision especially in large lesions and lesions in posterior fossa.

 

 

 

Name of Project/Title

rTMS induced modulations of functional connectivity in writers cramp

Investigator 

-          Principal investigator

-          Co- Principal investigator

 

Dr Bhaskar

Dr Rose Dawn Bharath

Total duration of the project

3 years

Funding Agency (ies)

Non funded

Total funding

NA

Funding during the year 2012-13

NA

Status

Completed

Background and purpose:Writer’s Cramp (WC) is a focal task-specific dystonia of the hand which is increasingly being accepted as a network disorder.Non-invasive cortical stimulation using repetitive transcranial magnetic stimulation (rTMS) has found therapeutic benefits in some of these patients. This studyaims to visualize the motor network abnormalities in WC and also its modulations usingthe resting state functional MRI (rsfMRI).

Methods: Nineteen patients with right-sided WC and 20 matched healthy controls (HC) were prospectively evaluated. All patients underwent single session of rTMSand rsfMRIwas acquired before (R1) and after rTMS(R2) . Seed based functional connectivity analysis of several regions in the motor network was performed for HC, R1 and R2 using SPM 8. Thresholded (p<0.05, FDR corrected) group level mean correlation maps were used to derive significantly connected ROI pairs.

Results:WC had significant reduction in the resting state functional connectivity in comparison with HC involving left cerebellum, thalamus, globus-pallidus, putamen, and bilateral supplementary motor area, right medial prefrontal lobe and right post central gyrus. After rTMS there was a significant increase in the contra lateral RSFC through the left thalamus- right globuspallidus-right thalamus- right prefrontal lobe network loop.

Conclusions:We conclude that writer’s cramp is a network disorder with widespread dysfunction much larger than clinically evident and changes induced by rTMSprobably acts through subcortical and trans hemispheric unaffected connections. Longitudinal studies with therapeutic  rTMS will be required to ascertain whether such information could be used to triage patients  prior to rTMS therapy.

 

 

 

Name of Project/Title

Comparison Of Different Sequences Of Images For Effective Brain Tumor Detection, Segmentation And Volume Measurement

Investigator 

-          Principal investigator

-          Co- Principal investigator

 

Chandrajit Prasad

Dr. A.K Gupta

Total duration of the project

6 months

Funding Agency (ies)

NIMHANS

Total funding

Rs. 96,000/-

Funding during the year 2012-13

Same as above

Status

Completed.

Results / report*

In this project we have presented a Knowledge Based Brain Tumor segmentation system. It was designed, tested and evaluated for efficient brain tumor segmentation. Two radiologists hand-labeled the tumor slices of interest and performance parameters were drawn by comparing these manually labeled slices with the ones generated by KBBTS. The images shown in the results showed that the system was successful in segmenting the tumor from healthy brain pixels. The mean values for sensitivity, specificity, accuracy, PPV and NPV were found to be 94.79%, 99.6%, and 99.39%, 91.64% and 99.76% respectively

 

Student Research Topics:

1.      Clinical presentation, endovascular management and outcome of spinal DAVF. Dr SubenduParida

2.      Brain structural changes in solvent abuse patients. DrSubenduParida

3.      Neuropsychological impairment and its radiological correlates in the survivors of HSV encephalitis. Dr Gorky Medhi

4.       Clinical presentation, endovascular management and outcome in pial AVF patients. Dr Gorky Medhi

5.      Resting state connectivity in Children with febrile convulsions : Dr Ullas

6.      Resting state connectivity biomarkers in patients with spinal cord injury: D Shriram