Browsing by Author "Thomas, B"

Now showing 1 - 20 of 75
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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 hospital-based registry of Creutzfeldt-Jakob disease: Can neuroimaging serve as a surrogate biomarker?
    (NEUROLOGY INDIA, 2016) Divya, KP; Menon, RN; Thomas, B; Nair, M
    Aim: This study addresses the role of neuroimaging in addition to the available clinical criteria for Creutzfeldt-Jakob disease (CJD) and its impact on its diagnosis in the absence of cerebrospinal fluid (CSF) biomarkers and tissue-based approaches. Methods: From a tertiary referral center in the city of Trivandrum, Kerala, South India, patients with rapidly progressive dementia (RPD) who fulfilled the World Health Organization (WHO) 1998 diagnostic criteria for CJD were included in this study. Their electrophysiological-clinical-radiological data were retrospectively studied and the results were analyzed. The other biomarkers of CJD were not assessed in the study. Results: Of the 96 patients with RPD, 41 patients were diagnosed as having a 'probable' and 'possible' CJD using the WHO 1998 diagnostic criteria between 2000 and 2013. While 92% patients satisfied the University of California, San Francisco (UCSF) 2007 and European magnetic resonance imaging (MRI)-CJD consortium criteria (2009), only 73% satisfied the MRI components of these criteria in addition to the more stringent, proposed UCSF MRI criteria (2011). The latter required the presence of diffusion weighted imaging abnormalities more than fluid attenuation inversion recovery abnormalities in the cortical and subcortical regions for the establishment of diagnosis on MRI of 'definite' (53.7%) and 'probable' CJD (19.5%). Conclusions: Significant heterogeneity exists in the presentation of CJD with only 48.8% patients simultaneously satisfying the MRI and electrophysiological criteria, suggesting that the diagnosis is impacted by these components in any of the currently prevalent criteria. With 27% of the cohort not meeting the radiological criteria, CSF and molecular biomarker assays may be reserved for MRI negative patients with suspected CJD and in atypical presentations.
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    A Potential Biomarker in Amyotrophic Lateral Sclerosis: Can Assessment of Brain Iron Deposition with SWI and Corticospinal Tract Degeneration with DTI Help?
    (AMERICAN JOURNAL OF NEURORADIOLOGY, 2016) Sheelakumari, R; Madhusoodanan, M; Radhakrishnan, A; Ranjith, G; Thomas, B
    BACKGROUND AND PURPOSE: Iron-mediated oxidative stress plays a pivotal role in the pathogenesis of amyotrophic lateral sclerosis. This study aimed to assess iron deposition qualitatively and quantitatively by using SWI and microstructural changes in the corticospinal tract by using DTI in patients with amyotrophic lateral sclerosis. MATERIALS AND METHODS: Seventeen patients with amyotrophic lateral sclerosis and 15 age- and sex-matched controls underwent brain MR imaging with SWI and DTI. SWI was analyzed for both signal-intensity scoring and quantitative estimation of iron deposition in the anterior and posterior banks of the motor and sensory cortices and deep gray nuclei. The diffusion measurements along the corticospinal tract at the level of pons and medulla were obtained by ROI analysis. RESULTS: Patients with amyotrophic lateral sclerosis showed reduced signal-intensity grades in the posterior bank of the motor cortex bilaterally. Quantitative analysis confirmed significantly higher iron content in the posterior bank of the motor cortex in patients with amyotrophic lateral sclerosis. In contrast, no significant differences were noted for the anterior bank of the motor cortex, anterior and posterior banks of the sensory cortex, and deep nuclei. Receiver operating characteristic comparison showed a cutoff of 35g Fe/g of tissue with an area under the curve of 0.78 (P = .008) for the posterior bank of the motor cortex in discriminating patients with amyotrophic lateral sclerosis from controls. Fractional anisotropy was lower in the pyramidal tracts of patients with amyotrophic lateral sclerosis at the pons and medulla on either side, along with higher directionally averaged mean diffusivity values. The combination of SWI and DTI revealed an area under the curve of 0.784 for differentiating patients with amyotrophic lateral sclerosis from controls. CONCLUSIONS: Measurements of motor cortex iron deposition and diffusion tensor parameters of the corticospinal tract may be useful biomarkers for the diagnosis of clinically suspected amyotrophic lateral sclerosis.
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    Acute encephalopathy with a lesion of the splenium of the corpus callosum - A report of two cases
    (BRAIN & DEVELOPMENT, 2012) Iype, M; Ahamed, S; Thomas, B; Kailas, L
    We report two cases of encephalopathy following a short febrile illness. Case one was a five year old child whose magnetic resonance imaging (MRI) of the brain showed a reversible discrete lesion in the splenium of the corpus callosum (SCC) and a ten year old boy who had extensive hyperintensity of the SCC. As these children have presented while there was an outbreak of influenza in our locality and since the second child tested positive for H1N1 antigen on PCR test, we feel that as previous authors have pointed out, these cases are cases of possible influenza encephalopathy. This awareness needs to be disseminated as this specific MRI finding should prompt one to test for H1N1 antigen and offer specific antiviral agent. Case one showed signs that support the existence of a splenial syndrome. (C) 2011 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.
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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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    An incidental persistent falcine sinus with dominant straight sinus and hypoplastic distal superior sagittal sinus
    (PEDIATRIC RADIOLOGY, 2006) Manoj, KS; Krishnamoorthy, T; Thomas, B; Kapilamoorthy, TR
    An incidental persistent falcine sinus was detected in an otherwise normal brain on MRI in a 12-year-old girl who underwent imaging after clinical suspicion of acute disseminated encephalomyelitis. The falcine sinus was associated with a hypoplastic posterior third of the superior sagittal sinus and a dominant straight sinus. Generally, atresia or hypoplasia of the straight sinus is associated with a persistent falcine sinus in postnatal life; otherwise, the falcine sinus disappears before birth. We discuss the embryological basis for such an association in this case.
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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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    Aneurysmal bone cyst of skull - A report of two cases
    (RIVISTA DI NEURORADIOLOGIA, 2005) Purkayastha, S; Gupta, AK; Kapilamoorthy, TR; Bodhey, NK; Thomas, B
    An aneurysmal bone cyst is a benign lesion usually involving the long bones, vertebrae including odontoid, hypoid and mandible. Skull is a rare site for aneurysmal bone cyst. Only 3% occur in the cranium and sites of involvement include temporal, occipital, orbital, frontal, parietal, ethmoids and sphenoid bones in order of frequency. We report two cases of aneurysmal bone cysts in occipital bone and maxilla. We discuss the radiological features, surgical findings and emphasize the role of endovascular management in these lesions.
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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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    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: 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 AMYLOID ANGIOPATHY-A CLINICORADIOLOGICAL STUDY FROM SOUTH INDIA
    (INTERNATIONAL JOURNAL OF STROKE, 2016) Sreedharan, SE; Thomas, B; Sylaja, PN; Sarma, PS
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    Clinico-radiological spectrum and outcome in idiopathic hypertrophic pachymeningitis
    (JOURNAL OF THE NEUROLOGICAL SCIENCES, 2015) Dash, GK; Thomas, B; Nair, M; Radhakrishnan, A
    Objective: To elucidate the clinico-radiological features, treatment response and outcome of a large cohort of patients (n = 20) with idiopathic hypertrophic pachymeningitis (IHP) and to examine if any of these features could differentiate between IHP and secondary causes of hypertrophic pachymeningitis (SHP). Methods: 20 patients with IHP diagnosed between 1998 and 2009 formed the study cohort. We adopted a validated clinical score to quantitatively assess and document their neurological disability and to compare their pre- and post-treatment outcomes. Appropriate statistical analysis was done to look for any clinical and/or radiological features to differentiate IHP from SHP. Results: Out of the twenty eight consecutive patients with pachymeningitis, 20 were having IHP and 8 were having SHP (Tuberculosis-5, Sarcoidosis-2, Wegener's granulomatosis-1). In IHP, headache and visual symptoms dominated the clinical symptomatology (80% and 75%). In MRI, the peripheral pattern of contrast enhancement was more common with IHP (p = 0.03). The posterior falx and tentorium showing a hypointense center ("fibrosis") and enhancing periphery ("active inflammation") together mimicking "Eiffel-by-night" sign was found to be more commonly associated with IHP (60% vs 12.5%, p = 0.03). Biopsy was done in 9 patients. At a mean follow-up of 51 months (range 24-144 months), the mean pretreatment clinical score improved from 6.55 to 1.80 in 20 patients with IHP (p < 0.001). Conclusions: Our data on the largest cohort of patients with IHP would shed light into its dinico-radiological spectrum, treatment and outcome. The prognosis is satisfactory if managed appropriately. We have highlighted the role of MRI in differentiating between IHP and other causes of SHP. (C) 2015 Published by Elsevier B.V.
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    Coil embolization for intracranial aneurysms - An Indian experience
    (RIVISTA DI NEURORADIOLOGIA, 2003) Gupta, AK; Joseph, S; Bhattacharya, RN; Kapilamoorhty, TR; Kesavadas, C; Thomas, B
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    Collateral Assessment by CT Angiography as a Predictor of Outcome in Symptomatic Cervical Internal Carotid Artery Occlusion
    (AMERICAN JOURNAL OF NEURORADIOLOGY, 2017) Sundaram, S; Kannoth, S; Thomas, B; Sarma, PS; Sylaja, PN
    BACKGROUND AND PURPOSE: Cervical internal carotid artery occlusion can present with varied clinical manifestations such as transient ischemic attack, stroke, and chronic ocular ischemia, or can be asymptomatic. The outcome in these patients is considerably influenced by cerebral hemodynamic compensatory adaptation of the intracranial collateral pathways. Our aim was to study whether collateral circulation as assessed by CT angiography can predict 3-month outcome and initial stroke severity in patients with symptomatic cervical ICA occlusion. MATERIALS AND METHODS: This was a retrospective study of 65 patients with symptomatic cervical ICA occlusion from January 2011 to December 2013. The collateral vessels (anterior and posterior communicating arteries, ophthalmic artery, and leptomeningeal arteries) were assessed by CTA. The outcome at 3 months was defined as poor if the modified Rankin Scale score was >= 3. RESULTS: The mean age of subjects was 57 +/- 11.6 years (range, 32-80 years), and 92% were men. Thirty-three (50.8%) patients had poor outcome. Absence of the ipsilateral ophthalmic artery, poor leptomeningeal collaterals, and <2 collaterals were predictors of stroke severity at onset and poor 3-month outcome in univariate analysis. In the multiple logistic regression analysis, inadequate flow through the secondary collaterals.(ipsilateral ophthalmic artery or leptomeningeal collaterals; OR, 4.5; 95% CI, 1.4-14.9; P =.01) and higher NIHSS score at stroke onset (OR, 19.2; 95% CI, 2.2-166.2; P =.007) independently predicted poor outcome at 3 months. CONCLUSIONS: Assessment of collateral circulation with CTA can be a useful predictor of 3-month outcome in patients with symptomatic cervical ICA occlusion.