Browsing by Author "Radhakrishnan, N"

Now showing 1 - 14 of 14
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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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    Characterizing the biocompatibility and tumor-imaging capability of Cu2S nanocrystals in vivo
    (NANOSCALE, 2015) Poulose, AC; Veeranarayanan, S; Mohamed, MS; Sakamoto, Y; Hirosawa, N; Suzuki, Y; Zhang, MF; Yudasaka, M; Radhakrishnan, N; Maekawa, T; Mohanan, PV; Kumar, DS
    Multifunctional nanomaterial-based probes have had key impacts on high-resolution and high-sensitivity bioimaging and therapeutics. Typically, NIR-absorbing metal sulfide-based nanocrystals (NCs) are highly assuring due to their unique optical properties. Yet, their in vivo behavior remains undetermined, which in turn undermines their potential bioapplications. Herein, we have examined the application of PEGylated Cu2S NCs as tumor contrast optical nanoprobes as well as investigated the short-and long-term in vivo compatibility focusing on anti-oxidant defense mechanism, genetic material, immune system, and vital organs. The studies revealed an overall safe profile of the NCs with no apparent toxicity even at longer exposure periods. The acquired observations culminate into a set of primary safety data of this nano-material and the use of PEGylated Cu2S NCs as promising optical nanoprobes with immense futuristic bioapplications.
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    Characterizing the biocompatibility and tumorimaging capability of Cu2S nanocrystals in vivo
    (Nanoscale, 2015-09) Poulose, AC; Veeranarayanan, V; Mohamed, MS; Sakamoto, Y; Zhang, M; Yudasaka, M; Radhakrishnan, N; Maekawa, T; Mohanan, PV; Kumar, DS
    Multifunctional nanomaterial-based probes have had key impacts on high-resolution and high-sensitivity bioimaging and therapeutics. Typically, NIR-absorbing metal sulfide-based nanocrystals (NCs) are highly assuring due to their unique optical properties. Yet, their in vivo behavior remains undetermined, which in turn undermines their potential bioapplications. Herein, we have examined the application of PEGylated Cu2S NCs as tumor contrast optical nanoprobes as well as investigated the short- and long-term in vivo compatibility focusing on anti-oxidant defense mechanism, genetic material, immune system, and vital organs. The studies revealed an overall safe profile of the NCs with no apparent toxicity even at longer exposure periods. The acquired observations culminate into a set of primary safety data of this nanomaterial and the use of PEGylated Cu2S NCs as promising optical nanoprobes with immense futuristic bioapplications
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    Early resective surgery causes favorable seizure outcome in malformations of cortical development
    (EPILEPSY RESEARCH, 2016) Radhakrishnan, A; Menon, R; Menon, D; Singh, A; Radhakrishnan, N; Vilanilam, G; Abraham, M; Thomas, B; Kesavadas, C; Varma, RP; Thomas, SV
    Purpose: We analyzed consecutive cases of a large cohort of the spectrum of malformations of cortical development (MCDs) including focal cortical dysplasias (FCDs) who underwent presurgical evaluation through our epilepsy program from January 2000-December 2010. We analyzed factors predicting surgical candidacy, predictors of seizure outcome and reasons for deferring surgery. Methods: 148 patients with MCD underwent detailed presurgical evaluation and 69 were operated. MCD was diagnosed based on characteristic findings in MRI and re-confirmation by histopathology in operated patients. Post-operative seizure outcome of non-operated and operated patients were assessed every 3 and 12 months and yearly intervals. Multivariate analysis and backward step-wise logistic regression analyzed factors predicting seizure outcome. Kaplan-Meier analysis predicted seizure-free survival rates. Results: 66.67% patients were seizure-free and aura-free at last follow-up. On multivariate logistic regression, the predictors of seizure freedom in operated MCDs were completeness of resection (odds ratio 8.2; 95% CI 1.43-64.96, p = 0.01), shorter duration of epilepsy (odds ratio 1.19, 95% CI 1.02-1.39, p = 0.02), and absence of spikes in post-operative EEG at one year (odds ratio 4.2; 95% CI 2.52-16.6; p <0.002). In FCD sub-group, shorter duration of epilepsy (11.1 versus 16.1 years, p = 0.03), absence of secondary generalized seizures (p = 0.05), absence of spikes in post-operative EEG on seventh day (p = 0.009) and one year (p = 0.002) were associated with favorable seizure outcome. Conclusion: Majority of patients with MCD and refractory epilepsy when operated early remains seizure free. Shorter duration of epilepsy is the single most important pre-operative variable and absence of spikes in post-operative EEG, predicts a long-term favorable seizure outcome. (c) 2016 Elsevier B.V. All rights reserved.
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    Intact Giant Abdominal Aortic Aneurysm Due to Takayasu Arteritis
    (ANNALS OF VASCULAR SURGERY, 2013) Parameshwarappa, SK; Mandjiny, N; Rajagopalan, BK; Radhakrishnan, N; Samavedam, S; Unnikrishnan, M
    A 35-year-old male fisherman was admitted with complaints of increasing back pain and abdominal discomfort of 1-year duration. Physical examination revealed a prominently visible, expansile, pulsatile, well-defined, nontender abdominal mass in the epigastric, umbilical and both lumbar areas. Computed tomographic (CT) angiography revealed a large juxtarenal aortic aneurysm with a maximum transverse diameter of 14.7 cm with bi-iliac extensions. Anatomy of the aneurysm did not permit endovascular aneurysm repair (EVAR). The patient underwent open surgical inclusion repair using an aorto-bi-iliac, 16 mm x 8 mm, collagen-impregnated, bifurcated Dacron graft. Postoperative recovery was uncomplicated and he left the hospital on postoperative day 5 in good health and has remained so up to the most recent 8-month follow-up. Histopathologic study showed signature features of Takayasu arteritis.
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    Non-functioning pituitary adenoma and concomitant Rathke's cleft cyst
    (INDIAN JOURNAL OF PATHOLOGY AND MICROBIOLOGY, 2011) Radhakrishnan, N; Menon, G; Hingwala, DR; Radhakrishnan, VV
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    Primary spinal epidural diffuse large B-cell lymphoma
    (NEUROLOGY INDIA, 2013) Jagtap, SA; Patil, AS; Kesavdas, C; Radhakrishnan, N; Soni, H; Satish, KS
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    Primary yolk sac tumor of the paracavernous region
    (ACTA NEUROCHIRURGICA, 2010) Radhakrishnan, N; Rao, RM; Kapilamoorthy, TR; Radhakrishnan, VV
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    Rosette forming glioneuronal tumor of the fourth ventricle in squash cytology smear
    (JOURNAL OF CYTOLOGY, 2014) Nair, AR; Gopalakrishnan, CV; Kapilamoorthy, TR; Radhakrishnan, N
    Rosette forming glioneuronal tumor (RGNT) is a recently recognized and extremely rare glioneuronal tumor occurring in the fourth ventricle. It is crucial for the cytopathologist to be aware of this entity as it can be easily mistaken for more common neoplasms occurring at this site. We present here the cytology of such a rare case of RGNT that was misdiagnosed as ependymoma. The varying cytological features of this entity, as well as the common diagnostic difficulties encountered in cytology, are highlighted in this report.
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    Sturge-Weber Syndrome: Clinical Spectrum, Disease Course, and Outcome of 30 Patients
    (JOURNAL OF CHILD NEUROLOGY, 2013) Jagtap, S; Srinivas, G; Harsha, KJ; Radhakrishnan, N; Radhakrishnan, A
    Sturge-Weber syndrome is a heterogeneous neurocutaneous syndrome with facial and leptomeningeal angiomas, glaucoma, seizures, stroke-like episodes, and mental retardation. The authors critically evaluated the clinical manifestations, outcome, and natural history in 30 patients with Sturge-Weber syndrome followed up from January 1985 to May 2010. Of the patients, 15 were males, age at diagnosis ranged from 1 month to 43 years. Typical port-wine stain nevus occurred in 26 (86%), it was bilateral in 2 (8%), and it was absent in 4 (4%). Nine patients had glaucoma (30%), 3 required surgery. Four had transient hemiparesis. All patients had seizures; they were well controlled in 22 (73.3%); in 8 they remained drug resistant. Three patients underwent surgery and became seizure-free. Of the 17 who had mental subnormality, 14 (82.4%) had seizure onset before 2 years. An early age at seizure onset and those with drug-resistant seizures had more severe degree of mental subnormality. Uncontrolled seizures, mental subnormality, visual handicap, and cosmetic disfiguration were the major impediments in life.
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    Successful mechanical thrombectomy of acute middle cerebral artery occlusion due to vegetation from infective endocarditis
    (NEUROLOGY INDIA, 2012) Sukumaran, S; Jayadevan, ER; Mandilya, A; Sreedharan, SE; Harikrishnan, S; Radhakrishnan, N; Sylaja, PN
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    Surgery for "Long-term epilepsy associated tumors (LEATs)": Seizure outcome and its predictors
    (Clin Neurol Neurosurg, 2016-02) Radhakrishnan, A; Abraham, M; Vilanilam, G; Menon, R; Menon, D; Kumar, H; Cherian, A; Radhakrishnan, N; Kesavadas, C; Thomas, B; Sarma, SP; Thomas, SV
    Objectives: “Long-term epilepsy associated tumors (LEATs)” by definition are tumors primarily causing drug-resistant seizures for two years or more. They include low-grade glial and glioneuronal tumors with normal life expectancy. We studied a large cohort of patients with LEATs who underwent surgery through our epilepsy program. Patients & methods: From 1998–2011, 105 patients with LEATs underwent surgery in our center. We utilized their data archived in a prospective registry to evaluate their electro-clinical-imaging characteristics affecting the long-term seizure outcome. Results: Of 105patients (age 3–50 years),meanage at surgery was 20 years andmeanpre-surgicalduration of epilepsy was 10.9 years. 66 (62.8%) had secondary generalized seizures. 82 had temporal tumors, 23 had extra temporal (13 frontal, 3 parietal, 2 occipital and 5 multilobar lesions) and four had associated hippocampal sclerosis. The interictal discharges and ictal onset were concordant to the lesion in 82 (78%) and 98 (93%) patients respectively. Lesionectomy and/or adjoining corticectomy or temporal lobectomy was done. Ganglioglioma was the most dominant pathological substrate in 61 (58%). During a mean follow-up of 7.5 years (range 3–16 years), 78/105 (74.2%) were seizure-free and 45 (57.4%) were totally off drugs. Secondary generalized seizures (p-0.02), temporal location of tumor (p-0.008) and spikes in third month post-operative EEG (p-0.03) caused unfavorable seizure outcome. A pre-surgical duration of epilepsy of more than 6.6 years caused less than optimal surgical outcome Conclusions: Early surgery should be considered a priority in LEATs. Presence of secondary generalized seizures is the single most important predictor of a poor seizure outcome
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    Tanycytic ependymoma of filum terminale: A case report
    (CLINICAL NEUROLOGY AND NEUROSURGERY, 2012) Radhakrishnan, N; Nair, NS; Hingwala, DR; Kapilamoorthy, TR; Radhakrishnan, VV
    Tanycytic ependymoma is an uncommon but well-recognized variant of ependymoma. Here we report a case of tanycytic ependymoma occurring at the region of filum terminale in a 44-year male who presented with low backache, bilateral lower limb weakness and urinary incontinence. MR imaging in this patient showed a lesion that was composed of solid and cystic components and was suggestive of ependymoma. The filum terminale region is an extremely unusual location for the occurrence of tanycytic ependymoma. To the best of our knowledge this is the third case of tanycytic ependymoma occurring in the filum terminale region. (C) 2011 Elsevier B.V. All rights reserved.