Browsing by Author "Kesavadas, C"

Now showing 1 - 20 of 98
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    3D-CISS MRI in a purely intracanalicular cochlear schwannoma
    (JOURNAL OF NEURORADIOLOGY, 2008) Thomas, B; Krishnamoorthy, T; Arvinda, HR; Kesavadas, C
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    A Genetic Algorithm Optimized Artificial Neural Network for the Segmentation of MR Images in Frontotemporal Dementia
    (SWARM, EVOLUTIONARY, AND MEMETIC COMPUTING, PT II (SEMCCO 2013), 2013) Kumari, RS; Varghese, T; Kesavadas, C; Singh, NA; Mathuranath, PS
    Frontotemporal Dementia (FTD) is an early onset dementia with atrophy in frontal and temporal regions. The differential diagnosis of FTD remains challenging because of the overlapping behavioral symptoms in patients, which have considerable overlap with Alzheimer's disease (AD). Neuroimaging analysis especially Magnetic Resonance Image Imaging (MRI) has opened up a new window to identify, and track disease process and progression. In this paper, we introduce a genetic algorithm (GA) tuned Artificial Neural Network (ANN) to measure the structural changes over a period of 1year. GA is a heuristic optimization method based on the Darwin's principle of natural evolution. The longitudinal atrophy patterns obtained from the proposed approach could serve as a predictor of impending behavioral changes in FTD subjects. The performance of our computerized scheme is evaluated and compared with the ground truth information. Using the proposed approach, we have achieved an average classification accuracy of 95.5 %, 96.5% and 98% for GM, WM and CSF respectively.
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    Acquired hepatolenticular degeneration: Is the T1 hyperintensity due to manganese deposition?
    (NEUROLOGY INDIA, 2009) Baheti, NN; Hassan, H; Rathore, C; Krishnan, S; Kesavadas, C
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    Advanced magnetic resonance imaging with histopathological correlation in papillary tumor of pineal region: Report of a case and review of literature
    (NEUROLOGY INDIA, 2010) Vaghela, V; Radhakrishnan, N; Radhakrishnan, VV; Menon, G; Kesavadas, C; Thomas, B
    Papillary tumors of the pineal region are recently described as rare mass lesions with limited literature available on their natural history and imaging features. Magnetic resonance imaging (MRI) including perfusion, diffusion, and spectroscopic features were described in an 18-year-old girl with papillary tumor of pineal region. A well-defined, T1 hyperintense and contrast-enhancing mass lesion was noted in pineal region with few cystic spaces within. Solid portion of lesion showed minimal diffusion restriction with average apparent diffusion coefficient of 0.812 x 10(-3) mm(2)/s: on MR spectroscopy elevated myo-inositol peak with reduced N-acetylaspartate and elevated choline in the tumor. On perfusion study there was significantly high relative cerebral blood volume (rCBV) (6-9 times) and relative cerebral blood flow (rCBF). Our findings agree with previous descriptions of cystic areas with T1 hyperintense appearance of this tumor but very high level of tumor perfusion, diffusion restriction, and presence of myo-inositol peak are important imaging findings and may correlate with the recent reports of high tumor recurrence in these cases.
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    Advanced magnetic resonance imaging with histopathological correlation in papillary tumor of pineal region: report of a case and review of literature.
    (Neurology India, 2010)
    Papillary tumors of the pineal region are recently described as rare mass lesions with limited literature available on their natural history and imaging features. Magnetic resonance imaging (MRI) including perfusion, diffusion, and spectroscopic features were described in an 18-year-old girl with papillary tumor of pineal region. A well-defined, T1 hyperintense and contrast-enhancing mass lesion was noted in pineal region with few cystic spaces within. Solid portion of lesion showed minimal diffusion restriction with average apparent diffusion coefficient of 0.812 Chi 10 -3 mm 2 /s; on MR spectroscopy elevated myo-inositol peak with reduced N-acetylaspartate and elevated choline in the tumor. On perfusion study there was significantly high relative cerebral blood volume (rCBV) (6-9 times) and relative cerebral blood flow (rCBF). Our findings agree with previous descriptions of cystic areas with T1 hyperintense appearance of this tumor but very high level of tumor perfusion, diffusion restriction, and presence of myo-inositol peak are important imaging findings and may correlate with the recent reports of high tumor recurrence in these cases.
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    Advanced MRI in Rosai-Dorfman disease: Correlation with histopathology
    (JOURNAL OF NEURORADIOLOGY, 2011) Hingwala, D; Neelima, R; Kesavadas, C; Thomas, B; Kapilamoorthy, TR; Radhakrishnan, VV
    Rosai-Dorfman disease is an idiopathic benign lymphoproliferative disorder that can, on rare occasions, cause intracranial or intraspinal lesions with non-specific features on conventional imaging. For this reason, its diagnosis is based on the classical pathological findings of histiocyte proliferation and emperipolesis. In this case report, we describe the imaging features of Rosai-Dorfman disease as visualized by newer types of MRI sequences, such as diffusion tensor imaging (DTI), susceptibility-weighted imaging (SWI) and perfusion-weighted imaging (PWI). In fact, combining the findings of conventional cross-sectional imaging with high fractional anisotropy (FA), a low apparent diffusion coefficient (ADC), mild blooming on SWI and decreased perfusion can help to make the diagnosis of Rosai-Dorfman disease. These newer tools can also be used to clarify the pathology of Rosai-Dorfman disease. (C) 2010 Elsevier Masson SAS. All rights reserved.
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    Analyzing functional, structural, and anatomical correlation of hemispheric language lateralization in healthy subjects using functional MRI, diffusion tensor imaging, and voxel-based morphometry
    (NEUROLOGY INDIA, 2015) James, JS; Kumari, SR; Sreedharan, RM; Thomas, B; Radhkrishnan, A; Kesavadas, C
    Context: To evaluate the efficacy of diffusion fiber tractography (DFT) and voxel-based morphometry (VBM) for lateralizing language in comparison with functional magnetic resonance imaging (fMRI) to noninvasively assess hemispheric language lateralization in normal healthy volunteers. Aims: The aim of the present study is to evaluate the concordance of language lateralization obtained by diffusion tensor imaging (DTI) and VBM to fMRI, and thus to see whether there exists an anatomical correlate for language lateralization result obtained using fMRI. Settings and Design: This is an advanced neuroimaging study conducted in normal healthy volunteers. Subjects and Methods: Fifty-seven normal healthy subjects (39 males and 18 females; age range: 15-40 years) underwent language fMRI and 30 underwent direction DTI. fMRI language laterality index (LI), fiber tract asymmetry index (AI), and tract-based statistics of dorsal and ventral language pathways were calculated. The combined results were correlated with VBM-based volumetry of Heschl's gyrus (HG), planum temporale (PT), and insula for lateralization of language function. Statistical Analysis Used: A linear regression analysis was done to study the correlation between fMRI, DTI, and VBM measurements. Results: A good agreement was found between language fMRI LI and fiber tract AI, more specifically for arcuate fasciculus (ArcF) and inferior longitudinal fasciculus (ILF). The study demonstrated significant correlations (P < 0.05) between blood-oxygen-level dependent (BOLD) fMRI activations, tract-based statistics, and PT and HG volumetry for determining language lateralization. Conclusions: A strong one-to-one correlation between fMRI, laterality index, DTI tractography measures, and VBM-based volumetry measures for determining language lateralization exists.
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    Arcuate fasciculus laterality by diffusion tensor imaging correlates with language laterality by functional MRI in preadolescent children
    (NEURORADIOLOGY, 2015) Sreedharan, RM; Menon, AC; James, JS; Kesavadas, C; Thomas, SV
    Language lateralization is unique to humans. Functional MRI (fMRI) and diffusion tensor imaging (DTI) enable the study of language areas and white matter fibers involved in language, respectively. The objective of this study was to correlate arcuate fasciculus (AF) laterality by diffusion tensor imaging with that by fMRI in preadolescent children which has not yet been reported. Ten children between 8 and 12 years were subjected to fMRI and DTI imaging using Siemens 1.5 T MRI. Two language fMRI paradigms-visual verb generation and word pair task-were used. Analysis was done using SPM8 software. In DTI, the fiber volume of the arcuate fasciculus (AFV) and fractional anisotropy (FA) was measured. The fMRI Laterality Index (fMRI-LI) and DTI Laterality Index (DTI-LI) were calculated and their correlation assessed using the Pearson Correlation Index. Of ten children, mean age 10.6 years, eight showed left lateralization while bilateral language lateralization was seen in two. AFV by DTI was more on the left side in seven of the eight children who had left lateralization by fMRI. DTI could not trace the AF in one child. Of the two with bilateral language lateralization on fMRI, one showed larger AFV on the right side while the other did not show any asymmetry. There was a significant correlation (p < 0.02) between fMRI-LI and DTI-LI. Group mean of AFV by DTI was higher on the left side (2659.89 +/- 654.75 mm(3)) as compared to the right (1824.11 +/- 582.81 mm(3)) (p < 0.01). Like fMRI, DTI also reveals language laterality in children with a high degree of correlation between the two imaging modalities.
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    Atypical MRI appearance of desmoplastic infantile ganglioglioma
    (PEDIATRIC RADIOLOGY, 2005)
    We report the atypical MRI features and histopathological findings of a desmoplastic infantile ganglioglioma in an 8-year-old girl. The mass was predominantly solid with a large, solid, non-enhancing exophytic component. The adjacent brain showed cortical necrosis and white-matter gliosis, suggesting earlier hypoxia.
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    Bilateral perisylvian infarct: a rare cause and a rare occurrence
    (SINGAPORE MEDICAL JOURNAL, 2011) Singh, A; Kate, MP; Nair, MD; Kesavadas, C; Kapilamoorthy, TR
    Foix-Chavany-Marie opercular syndrome is a severe form of pseudobulbar palsy occurring due to bilateral anterior opercular lesions. We report a case of a 51-year-old man with sudden onset of inability to speak and dysphagia, and a history of synovial sarcoma of the right hand. Detailed language evaluation was normal. The patient had right upper motor neuron facial paresis and absent gag reflex bilaterally. Magnetic resonance (MR) imaging revealed acute and subacute infarcts involving the bilateral insular cortex. Two-dimensional echocardiography and cardiac MR imaging showed a mobile mass in the left atrium attached to the interatrial septum, which was likely a myxoma. Chest radiograph and computed tomography imaging of the chest revealed multiple cannonball shadows that were suggestive of secondaries in the lung. The probable cause of the cerebral lesions was the mass lesion in the heart or metastatic lesions from the synovial sarcoma. The cardiac surgeon and surgical oncologist recommended palliative care.
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    Brain Tumor Segmentation by Integrating Symmetric Property with Region Growing Approach
    (2015 ANNUAL IEEE INDIA CONFERENCE (INDICON), 2015) Gupta, M; Gayatri, KS; Harika, K; Rao, BVVSNP; Rajagopalan, V; Das, A; Kesavadas, C
    Brain tumor segmentation is an important procedure for early diagnosis of brain tumor and planning of its treatment. However it is still a difficult task due to variations in size, shape and location of tumor. In this paper, we propose a novel brain tumor segmentation method using T2-weighted brain MR images by integrating symmetry property of brain with region growing approach. Bilateral symmetry property of brain is used in our method to identify various regions having probability of presence of the tumor. Identification of exact tumor location and its segmentation is then performed by using region growing technique. Qualitative and quantitative evaluation of proposed approach was performed and promising results have been demonstrated when compared with ground truth and other state of art method. The segmented tumor region obtained in our work can assist the doctors and radiologist in the diagnosis of brain tumor and treatment planning.
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    Calcified neurocysticercosis lesions and antiepileptic drug-resistant epilepsy: A surgically remediable syndrome?
    (EPILEPSIA, 2013) Rathore, C; Thomas, B; Kesavadas, C; Abraham, M; Radhakrishnan, K
    PurposeIn contrast to the well-recognized association between acute symptomatic seizures and neurocysticercosis, the association between antiepileptic drug (AED)-resistant epilepsy and calcified neurocysticercosis lesions (CNLs) is poorly understood. We studied the association between AED-resistant epilepsy and CNLs, including the feasibility and outcome of resective surgery. MethodsFrom the prospective database maintained at our epilepsy center, we reviewed the data of all patients with AED-resistant epilepsy who underwent presurgical evaluation from January 2001 to July 2010 and had CNL on imaging. We used clinical, neuroimaging, and interictal, ictal, and intracranial electroencephalography (EEG) findings to determine the association between CNL and epilepsy. Suitable candidates underwent resective surgery. Key FindingsForty-five patients fulfilled the inclusion criteria. In 17 patients, CNL was proven to be the causative lesion for AED-resistant epilepsy (group 1); in 18 patients, CNL was associated with unilateral hippocampal sclerosis (HS; group 2); and in 10 patients, CNLs were considered as incidental lesions (group 3). In group 1 patients, CNLs were more common in frontal lobes (12/17), whereas in group 2 patients, CNLs were more commonly located in temporal lobes (11/18; p=0.002). Group 2 patients were of a younger age at epilepsy onset than those in group 1 (8.97.3 vs. 12.6 +/- 6.8years, p=0.003). Perilesional gliosis was more common among patients in group 1 when compared to group 3 patients (12/17 vs. 1/10; p=0.006). Fifteen patients underwent resective surgery. Among group 1 patients, four of five became seizure-free following lesionectomy alone. In group 2, four patients underwent anterior temporal lobectomy (ATL) alone, of whom one became seizure-free; five underwent ATL combined with removal of CNL (two of them after intracranial EEG and all of them became seizure-free, whereas one patient underwent lesionectomy alone and did not become seizure-free. SignificanceIn endemic regions, although rare, CNLs are potential cause for AED-resistant and surgically remediable epilepsy, as well as dual pathology. Presence of perilesional gliosis contributes to epileptogenicity of these lesions. For those patients with CNL and HS, resection of both lesions favors better chance of seizure-free outcome.
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    CALCIFIED NEUROCYSTICERCUS LESIONS (CNL) AND DRUG RESISTANT EPILEPSY: SURGICALLY REMEDIABLE SYNDROME?
    (EPILEPSIA, 2013) Rathore, C; Thomas, B; Kesavadas, C; Abraham, M; Radhakrishnan, K
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    Calcified Neurocysticercus Lesions and Hippocampal Sclerosis: Potential Dual Pathology?
    (NEUROLOGY, 2012) Radhakrishnan, K; Rathore, C; Thomas, B; Kesavadas, C
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    Carotid artery stenting - An Indian experience
    (RIVISTA DI NEURORADIOLOGIA, 2003)
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    Carotid artery stenting: Results and long-term follow-up
    (NEUROLOGY INDIA, 2006)
    Background and Purpose: The role of carotid artery stenting (CAS) as an alternative to carotid endarterectomy in the treatment of for symptomatic carotid artery stenosis is investigated. Materials and Methods: Forty-seven patients underwent CAS over 10-year period. Forty-nine vessels were treated. Stenosis quantification was done using North American symptomatic carotid endarterectomy trial method. The mean follow-up period by clinical and Duplex examination ranged is 5.6 years. Results: The technical success rate was 100%. There were four deaths (8.1%) and two (4.1%) minor strokes within thirty days of procedure. There was no major strokes. All patients with minor stroke achieved complete recovery at 1-month follow up. Two deaths occurred probably due to hyperperfusion syndrome (HS) and two due to cardiac arrest. Conclusion: CAS is an effective treatment modality of symptomatic carotid artery disease but should be carefully done in high-risk groups having severe medical ailments and those having severe bilateral stenosis of the carotid arteries.
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    Cerebral dural arteriovenous fistulae - An Indian experience
    (RIVISTA DI NEURORADIOLOGIA, 2003) Gupta, AK; Joseph, S; Kapilamoorthy, TR; Bejoy, T; Kesavadas, C
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    Cerebral myxomatous angiopathy. Imaging features
    (RIVISTA DI NEURORADIOLOGIA, 2004) Sonwalkar, HA; Gupta, AK; Varma, DR; Purkayastha, S; Bodhey, N; Kesavadas, C
    Strokes due to embolization from a cardiac myxoma are rare. Myxomatous cerebral emboli can cause occlusion of intracranial vessels or oncotic aneurysm formation. We describe a case of cardiac myxoma presenting with stroke having bilateral cerebral infarct and oncotic aneurysm formation. Myxomatous emboli have characteristic CT, MR and angiography findings, which are well seen in this case. The pathogenesis, imaging features, clinical presentation and natural history are discussed.
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    Cerebral Small Vessel Disease and Motoric Cognitive Risk Syndrome: Results from the Kerala-Einstein Study
    (JOURNAL OF ALZHEIMERS DISEASE, 2016) Wang, N; Allali, G; Kesavadas, C; Noone, ML; Pradeep, VG; Blumen, HM; Verghese, J
    Background: The contribution of cerebral small vessel disease to cognitive decline, especially in non-Caucasian populations, is not well established. Objective: We examined the relationship between cerebral small vessel disease and motoric cognitive risk syndrome (MCR), a recently described pre-dementia syndrome, in Indian seniors. Methods: 139 participants (mean age 66.6 +/- 5.4 y, 33.1% female) participating in the Kerala-Einstein study in Southern India were examined in a cross-sectional study. The presence of cerebral small vessel disease (lacunar infarcts and cerebral microbleeds (CMB)) and white matter hyperintensities on MRI was ascertained by raters blinded to clinical information. MCR was defined by the presence of cognitive complaints and slow gait in older adults without dementia or mobility disability. Results: Thirty-eight (27.3%) participants met MCR criteria. The overall prevalence of lacunar infarcts and CMB was 49.6% and 9.4%, respectively. Lacunar infarcts in the frontal lobe, but no other brain regions, were associated with MCR even after adjusting for vascular risk factors and presence of white matter hyperintensities (adjusted Odds Ratio (aOR): 4.67, 95% CI: 1.69-12.94). Frontal lacunar infarcts were associated with slow gait (aOR: 3.98, 95% CI: 1.46-10.79) and poor performance on memory test (beta : -1.24, 95% CI: -2.42 to -0.05), but not with cognitive complaints or non-memory tests. No association of CMB was found with MCR, individual MCR criterion or cognitive tests. Conclusions: Frontal lacunar infarcts are associated with MCR in Indian seniors, perhaps, by contributing to slow gait and poor memory function.
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    Cerebrospinal fluid rhinorrhea and acquired anterior basal encephalocoele in a patient with colloid cyst of the third ventricle
    (NEUROLOGY INDIA, 2010) Deepak, KS; Kesavadas, C; Kapilamoorthy, TR; Menon, G