Browsing by Author "Kesavadas, C."
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Item Advanced MR imaging in Lhermitte-Duclos disease: moving closer to pathology and pathophysiology(NEURORADIOLOGY, 2007)Introduction Lhermitte-Duclos disease (LDD, dysplastic gangliocytoma) is an extremely rare cerebellar lesion of uncertain etiology. The debate as to whether it constitutes a neoplastic, malformative, or hamartomatous lesion is still continuing. In this report we explore the usefulness of susceptibility-weighted imaging (SWI), diffusion weighted imaging (DWI), perfusion imaging, and chemical shift imaging (CSI) in demonstrating the pathology and pathophysiology in two patients with LDD.Methods MR imaging of the brain and the cervicodorsal spine was performed on a 1.5-T scanner in a 47-year-old woman presenting with numbness and paresthesia of both upper and lower limbs, and in a 17-year-old male with right frontal headache associated with neck pain.Results Routine imaging in the first patient showed a leftside cerebellar mass with characteristic 'tiger-striped' thick folia associated with Chiari I malformation, tonsillar herniation and cervicodorsal syringomyelia and in the second patient a right cerebellar mass with similar findings. The SWI demonstrated the characteristic deep running veins between the folia, which is thought to be the cause for vascular contrast enhancement. Diffusion showed a T2 shine-through effect with mild increased diffusivity, and perfusion showed increase in relative cerebral blood volume, relative cerebral blood flow, and mean transit time in the lesion. MR spectroscopy demonstrated reduction in metabolites and a prominent lactate peak in both the patients. The pathological and pathophysiological significance of these findings is discussed.Conclusion MRI with the newer imaging capabilities can demonstrate the pathology and pathophysiology in Lhermitte-Duclos disease better. SWI helps in detecting the veins around the thickened folia.Item Atypical clinical and imaging manifestation in neurocysticercosis(ANNALS OF INDIAN ACADEMY OF NEUROLOGY, 2011)A 20-year-old man presented with left-sided headache and seizures of three years duration. Conglomerate ring-enhancing lesions were seen in the first magnetic resonance imaging study. He was initially treated with anticonvulsants for two years. Because the symptoms and the lesions were persisting, antitubercular treatment was added. He was asymptomatic after antitubercular treatment despite persisting lesion. Lesion showed exuberant ring enhancement with increased perfusion. Because the lesion was persisting even after 24 months of antitubercular treatment, excision was considered. Lesionectomy was done and histopathology reported meningoencephalitis secondary to neurocysticercosis. The case report highlights the difficulty in differentiating cysticercosis from tuberculoma in patients from countries where both the conditions are endemic.Item Atypical fungal granuloma of the sphenoid wing(JOURNAL OF NEURORADIOLOGY, 2009)A 29-year-old immunocompetent patient presented with a 3-month history of headache and vomiting. Computed tomography (CT) and conventional magnetic resonance imaging (MRI) revealed a mass lesion in the right sphenoid wing. The conventional imaging findings were typical of meningioma. However, diffusion-weighted imaging (DWI), susceptibility-weighted imaging (SWI) and perfusion-weighted imaging (PWI) all revealed details that were unusual for a meningioma. DWI showed diffusion blackout, perfusion was not raised in PWI, and susceptibility effects were noted in SWI. Based on these findings, the possibility of granuloma was kept as the differential diagnosis. Histopathological examination of the lesion was suggestive of fungal granuloma. This case report highlights the importance of advanced neuroimaging techniques in differentiating meningioma and granuloma. (C) 2009 Elsevier Masson SAS. All rights reserved.Item Dissecting intracranial aneurysms presenting as subarachnoid haemorrhage: report of two cases and review of literature(BRITISH JOURNAL OF NEUROSURGERY, 2008)Subarachnoid haemorrhage due to intracranial non-traumatic dissecting aneurysms is rare. Most of the published reports refer to dissecting aneurysms in the vertebrobasilar territory. Anterior circulation dissecting aneurysms are rare and their pathogenesis, clinical features, angiographic findings and management are a matter of debate. Management of patients with intracranial arterial dissection is unclear. Unlike the well-established proximal occlusion and trapping approaches to vertebral artery dissections, choices of interventions for anterior circulation and basilar dissecting aneurysms are limited, and most reports have been limited to wrapping techniques for arterial wall reinforcement. The role of anticoagulation therapy in the presence of subarachnoid haemorrhage is also a matter of debate. As no clear-cut guidelines are available, treatment should be tailored to the individual patient. We describe two cases of intracranial dissecting aneurysms, which presented as subarachnoid haemorrhage (SAH) and discuss the management issues.Item Endovascular treatment of direct carotid cavernous fistulae: a pictorial review(NEURORADIOLOGY, 2006)Introduction Direct carotid-cavernous fistulae (CCFs) are type A fistulae according to Barrow's classification. Endovascular treatment of these lesions is challenging.Methods The purpose of this review was to evaluate the endovascular treatment of direct CCFs. We also describe the technique, symptomatology and complications associated with the procedure and report on the long-term follow-up in our treated patients.Results A total of 89 patients with a direct CCF were treated. All patients had baseline brain CT or MR imaging. Treatment comprised transarterial balloon or coil embolizations. The patients were followed up at 1 month and then every 6 months thereafter. Detachable balloons were used in 79 fistulae. In 12 fistulae the balloon could not be negotiated through the fistula and these fistulae were treated with transarterial coil occlusion. Clinical outcomes of the treated patients evaluated at 1 month were: 79 patients (88.8%) cured, 9 (10.1%) significantly improved, 1 (1.1%) remaining static.Conclusion Endovascular treatment of direct CCFs is safe and effective and results in long-term cure.Item Endovascular treatment of scalp cirsoid aneurysms(NEUROLOGY INDIA, 2008)Background: Scalp is the most common site of soft tissue arteriovenous fistulae and surgical excision has been the primary mode of treatment. Endovascular treatment has evolved as an alternative to the surgery. Aims: To evaluate the effectiveness of percutaneous direct-puncture embolization of cirsoid aneurysms. Materials and Methods: From January 1995 to December 2004, 15 patients underwent percutaneous direct-puncture embolization of cirsoid aneurysms. Plain X-ray, computerized tomography scan and complete selective cerebral angiogram were done in all. Seven patients had forehead lesions, four had temporal and the remaining four patients had occipital region cirsoid aneurysms. Lesions were punctured with 21-gauge needle and embolized with 20-50% cyanoacrylate-lipiodol mixture. Circumferential compression was applied during injection. Results: Post-embolization angiogram showed complete obliteration in 11 patients. The remaining four patients required adjunctive transarterial embolization with polyvinyl alcohol particles for complete lesion devascularization. Two patients had post procedure surgery for removal of disfiguring and hard glue cast. There were no major procedure-related complications. No patients had any recurrence in the follow-up. Conclusion: Percutaneous direct puncture embolization of cirsoid aneurysms is a safe and effective procedure. It can be effectively used as an alternative to surgery. Sometimes adjunctive transarterial embolization is also required to deal with deeper feeders.Item Fluid-fluid levels in cystic lumbosacral schwannomas: a report of three cases(SINGAPORE MEDICAL JOURNAL, 2009)Magnetic resonance imaging features of three benign cystic lumbosacral schwannomas, which showed multiple fluid-fluid levels, are described. One of the tumours showed bone destruction with fluid-fluid levels that closely mimicked an aneurysmal bone cyst. Pathological examination confirmed haemorrhage as the cause of fluid-fluid levels in the tumours. Though a rare finding, fluid-fluid levels with bone destruction can also be caused by nerve sheath tumours and hence must be included in the list of differential diagnoses of spinal tumours.Item Fluoroscopic-guided balloon dilatation and stenting in tracheal stenosis with metallic self-expandable stents and long-term follow-up results(AUSTRALASIAN RADIOLOGY, 2007)The purpose of this study was to assess the safety and long-term efficacy of self-expandable stents in the treatment of benign tracheal stenosis. Nine patients (seven men) with tracheal stenosis (including one with fistula) of varied cause were treated by fluoroscopically guided balloon dilatation and stenting with self-expandable metallic stents. The procedure was carried out under topical spray in eight patients and under general anaesthesia in one patient. The patients were followed up for a period ranging between 13 and 60 months. in eight of the nine patients, satisfactory positioning of the stent was achieved at the first instance, with immediate relief of dyspnoea. One patient with innominate artery aneurysm died 16 days after the procedure because of renal failure. At 1 month of follow up, six out of eight (75%) of our live patients were without any respiratory embarrassment. This dyspnoea-free result reached almost 90% by the end of 1 year especially so in the fibrous strictures. Four out of the eight live patients (50%) had cough for 2 months and two (25%) had mild blood-tinged sputum treated by inhalation and mucolytic agents. Secondary intervention was required in one patient at 1 month because of recurrent symptoms. The patient with tracheo-oesophageal fistula required surgical intervention because of fracture of the stent. Fluoroscopically guided balloon dilatation and stenting of the tracheal stenosis is an effective non-surgical therapy resulting in cure of fibrous strictures and palliation in cases of malignancy.Item Focal Cortical Dysplasia (FCD) lesion analysis with complex diffusion approach(COMPUTERIZED MEDICAL IMAGING AND GRAPHICS, 2009)Identification of Focal Cortical Dysplasia (FCD) can be difficult due to the subtle MRI changes. Though sequences like FLAIR (fluid attenuated inversion recovery) can detect a large majority of these lesions, there are smaller lesions without signal changes that can easily go unnoticed by the naked eye. The aim of this study is to improve the visibility of focal cortical dysplasia lesions in the T1 weighted brain MRI images. In the proposed method, we used a complex diffusion based approach for calculating the FCD affected areas. Based on the diffused image and thickness map, a complex map is created. From this complex map; FCD areas can be easily identified. MRI brains of 48 subjects selected by neuroradiologists were given to computer scientists who developed the complex map for identifying the cortical dysplasia. The scientists were blinded to the MRI interpretation result of the neuroradiologist. The FCD could be identified in all the patients in whom surgery was done, however three patients had false positive lesions. More lesions were identified in patients in whom surgery was not performed and lesions were seen in few of the controls. These were considered as false positive. This computer aided detection technique using complex diffusion approach can help detect focal cortical dysplasia in patients with epilepsy. (C) 2009 Elsevier Ltd. All rights reserved.Item Focal neuronal loss, reversible subcortical focal T2 hypointensity in seizures with a nonketotic hyperglycemic hyperosmolar state(NEURORADIOLOGY, 2007)Introduction Neuroimaging in seizures associated with nonketotic hyperglycemia (NKH) is considered normal. We report magnetic resonance imaging (MRI) abnormalities in four patients with NKH and seizures.Methods We prospectively evaluated clinical and radiological abnormalities in four patients with NKH during the period March 2004 to December 2005.Results All patients presented with seizures, either simple or complex partial seizures or epilepsia partialis continua. Two of them had transient hemianopia. MRI showed subcortical T2 hypointensity in the occipital white matter and in or around the central sulcus (two patients each), T2 hyperintensity of the overlying cortex (two patients), focal overlying cortical enhancement (three patients) and bilateral striatal hyperintensity (one patient). Diffusion-weighted imaging (DWI) performed in three patients showed restricted diffusion. The ictal semiology and electroencephalographic (EEG) findings correlated with the MRI abnormalities. On clinical recovery, the subcortical T2 hypointensity and striatal hyperintensity reversed in all patients. The initial cortical change evolved to FLAIR hyperintensity suggestive of focal cortical gliosis. The radiological differential diagnosis considered initially included encephalitis, malignancy and hemorrhagic infarct rendering a diagnostic dilemma.Conclusion We identified subcortical T2 hypointensity rather than hyperintensity as a characteristic feature of seizures associated with NKH. Only very few similar reports exist in literature. Reversible bilateral striatal T2 hyperintensity in NKH has not been reported to the best of our knowledge.Item Glioma grading: sensitivity, specificity, positive and negative predictive values of diffusion and perfusion imaging(JOURNAL OF NEURO-ONCOLOGY, 2009)Purpose The purpose of our study was to determine the statistical significance of thresholds of relative cerebral blood volume (rCBV), apparent diffusion coefficient (ADC) and ADC ratios in grading cerebral gliomas. Materials and methods In this retrospective study, 51 patients with histopathologically confirmed primary cerebral gliomas who had undergone conventional MR imaging, dynamic contrast-enhanced T2*-weighted perfusion MR imaging and diffusion MR imaging were included. A retrospective blinded analysis of the imaging findings including the perfusion and diffusion parameters was done. The rCBV measurements were obtained from regions of maximum perfusion. Minimum ADC values were obtained from the region of maximum hypointensity within the tumor and from the corresponding opposite white matter. Tumor grade determined with the two methods were then compared with the histopathologic grade. Mann-Whitney tests were performed to compare the DWI and PWI between tumor types. Receiver operating characteristic analyses were performed to determine optimum thresholds for tumor grading and also to calculate the sensitivity, specificity, PPV, and NPV for identifying high-grade gliomas. Results Statistical analysis demonstrated a threshold value of 2.91 for rCBV to provide sensitivity, specificity, PPV, and NPV of 94.7, 93.75, 90.0, and 96.8%, respectively, in determining high-grade gliomas. An ADC value of 98.50 mm(2)/s was defined as a threshold below which tumors were classified as high-grade gliomas and a sensitivity, specificity, PPV, and NPV of 90, 87.1, 81.81 and 93.10% respectively, were obtained. Significant differences were noted in the rCBV ratios, ADC and ADC ratios between low- and high-grade gliomas (P < 0.0001). Conclusion Combining PWI and DWI with conventional MR imaging increases the accuracy of pre-operative imaging grading of glial neoplasms. The rCBV measurements had the most superior diagnostic performance in predicting glioma grade. Absolute ADC values or ADC ratios were also helpful in preoperative grading of gliomas. Threshold values can be used in a clinical setting to evaluate tumors preoperatively for histologic grade and provide a means for guiding treatment and predicting postoperative patient outcome.Item Intracranial infectious aneurysm: Presentation, management and outcome(JOURNAL OF THE NEUROLOGICAL SCIENCES, 2007)Background: Intracranial infectious aneurysms (IA) are infrequent, but can be fatal.Objectives: To compare the clinical profile of IAs associated with intravascular/systemic infection like infective endocarditis with that associated with local infections like meningitis, orbital cellulitis and cavernous sinus thrombosis.Methods: We analysed all cases of IA, treated in this Institute from 1976 to 2003, in order to identify prognostic factors.Results: There were 25 persons (mean age 24.8 +/- 17.3 years, males 17) with 29 IA (carotid circulation 19, vertebrobasilar circulation 10). Headache (83%) and fever (67%) were the most common presenting symptoms. In contrast to noninfectious aneurysms, intracerebral haemorrhage (60%) and focal signs were more common than subarachnoid haemorrhage (7%) with [A. Sources of infection were cardiac (10), meningitis (12), orbital cellulitis (2) or uncertain (I). Infective agents included bacteria (18), fungi (4), and tubercle bacilli (3). Fifteen]A were distal and 14 were proximal. IAs associated with meningitis were proximal (75%) while those associated with cardiac diseases preferentially involved carotid territory and were distal (p=0.013). The overall mortality was 32%. Survivors were younger than those who expired (p=0.015). Of the sixteen patients treated medically, seven recovered (44%), others (56%)) had treatment failure (three died and six required surgery later). Another five patients underwent early Surgery (one died). Mortality of IA was significantly higher with meningitis, fungal aetiology and vertebrobasilar location.Conclusions: IAs associated with local infections like meningitis had different clinical profile as compared to IAs associated with intravascular/systemic infections like infective endocarditis. (C) 2007 Elsevier B.V. All rights reserved.Item Intracranial Intradural Aneurysmal Bone Cyst: A Unique Case(PEDIATRIC NEUROSURGERY, 2009)Aneurysmal bone cyst (ABC) of the skull is exceedingly rare. We report a unique case of an intradural ABC without bone involvement presenting with raised intracranial pressure. The patient was a 14-year-old boy who presented with headache, vomiting and right focal seizure. Imaging showed a large multicystic left frontal lesion without any evidence of bone involvement. The lesion adherent to an intact sphenoid wing dura was completely excised. The histopathology report was consistent with an ABC. This case represents the first report of an ABC without involvement of the skull bones or any evidence of dural erosion. The possible mechanism of origin at this unusual location is hypothesized. Copyright (C) 2009 S. Karger AG, BaselItem Mean intensity curve on dynamic contrast-enhanced susceptibility-weighted perfusion MR imaging - review of a new parameter to differentiate intracranial tumors(JOURNAL OF NEURORADIOLOGY, 2011)Dynamic susceptibility contrast (DSC) perfusion imaging has been in clinical use for various indications, including characterization and grading of intracranial neoplasms. However, several technical factors can lead to pitfalls in image interpretation. This review discusses the extraction of T1 and T2* information from mean curve analysis of DSC perfusion imaging of various brain tumors, which provides further insights into tumor biology and, thus, may be useful in the differential diagnosis of such tumors. Indeed, by looking at the mean time signal intensity curve from the tumor bed in addition to the rCBV maps, it is possible to obtain further inferences of capillary density and lesion leakiness. When dynamic contrast enhanced (DCE) T1 perfusion is not available, DSC perfusion with mean curve analysis appears to be a valid alternative for characterizing various brain neoplasms in a routine clinical setting. (C) 2011 Elsevier Masson SAS. All rights reserved.Item Multifocal desmoplastic noninfantile astrocytoma(JOURNAL OF NEURORADIOLOGY, 2008)This is a report of a case of multifocal desmoplastic astrocytoma in an 11-year-old child in which we describe the MRI findings and discuss the possible mechanism of its development. The MRI appearances in our case support the view that the tumor is primarily of teptomeningeal or superficial cortical origin, with cystic formation secondary to entrapment of cerebrospinal fluid. The question of whether or not the lesions are metastases or metachronous lesions is also discussed. Desmoplastic astrocytoma at a noninfantile age is extremely rare: only four cases have been reported in the literature so far. Even more unusual is the presence of this lesion in multiple locations at the initial presentation. (C) 2008 Elsevier Masson SAS. All rights reserved.Item Percutaneous laser disc decompression: Clinical experience at SCTIMST and long term follow up(NEUROLOGY INDIA, 2006)Background: Low backache (LBA) is now increasing in younger population due to misdirected spinal kinetics secondary to improper posture, heavy load lifting and motorbike driving. Hence minimally invasive procedures are increasingly sought after. Among these, PLDD is currently popular and in use. We present our long term follow-up in the use of Nd:YAG laser for PLDD. Aim: To herniation of lumbar discs & long term follow up results. Materials and Methods: Forty patients with contained lumbar disc herniation on MRI and who did not respond to 6 weeks conservative treatment were subjected to PLDD. L4-5 disc was treated in 31, L5-S1 in 12 and L1-2 and L3-4 in one each. Nd:YAG laser at 1064 nm was used for the procedure. Total laser energy of 1500-2000 Joules was delivered at the disc space depending upon the size. Results: There was immediate pain relief in 32/40 (80%). According to MacNab criteria good to fair response was seen in 37/40 (92%) and 3 patients (7.5%) responded poorly to this treatment. On follow up which ranged from 1 to 7 years, 34/40 (85%) had pain relief with no need for further treatment. Complications: Significant pain at local puncture site was experienced by 8 (20%), pain during lasing was experienced by one. One patient developed muscular spasm. Conclusion: Percutaneous laser disc decompression is a safe, relatively noninvasive and effective treatment modality for contained, nonsequestered, herniated lumbar disc disease in carefully selected patients.Item Preoperative embolization of hypervascular head and neck tumours(AUSTRALASIAN RADIOLOGY, 2007)The embolization of vascular tumours of the head and neck has become an important adjunct to the surgical treatment of these tumours. A vascular tumour in the head and neck region in a surgically treatable patient may be a candidate for embolization. Palliative embolization may be the sole treatment for high risk patients. Reducing intraoperative bleeding may shorten surgery time thus decreasing morbidity and mortality. The purpose of this study is to assess the efficacy of embolization as an adjunct to surgery or as a curative measure in the management of hypervascular head and neck tumours. We retrospectively reviewed the records of 46 consecutive patients (27 men and 16 women; mean age, 37.8 years) with 48 hypervascular head and neck tumours that had undergone preoperative transarterial, direct puncture or combined mode of embolization. Diagnosis of tumours was made on the basis of findings of imaging studies. The 46 patients underwent embolization either through transarterial route, by direct puncture technique or both direct puncture and arterial route. The devascularization reached 90-95% with the use of NBCA. The amount of devascularization reached by transarterial particle embolization is a little lesser. One patient (carotid body tumour) developed mild unilateral seventh, ninth and 10th cranial nerve palsy after transarterial embolization, transient hemiparesis was seen in another patient (nasopharyngeal angiofibroma). Both patients improved completely with steroids and had no deficit on follow up. One patient developed delayed glue migration into the middle cerebral artery territory 6 h after the procedure with no reported increase in size of the lesion in the following 5 years. Preoperative embolization of hypervascular tumour of head and neck region appears to be safe and improves the chance of complete removal during surgery with minimal blood loss.Item Primary diffuse leptomeningeal gliomatosis(JOURNAL OF NEURORADIOLOGY, 2009)A 20-year-old woman with a history of seizures presented symptoms of walking difficulties for the past six months. Clinical examination was suggestive of a craniovertebral junction anomaly. A cerebrospinal fluid study showed mild protein elevation with no evidence of an infective pathology. Craniospinal MRI revealed diffuse nodular leptomeningeal enhancement of the brain and spinal cord. Histopathological examination was suggestive of a low-grade glioma, and the patient was diagnosed with primary diffuse leptomeningeal gliomatosis. So far, the patient has survived for more than 110 months without aggressive therapy. (C) 2008 Elsevier Masson SAS. All rights reserved.Item Rasmussen's encephalitis: Experience from a developing country based on a group of medically and surgically treated patients(SEIZURE-EUROPEAN JOURNAL OF EPILEPSY, 2009)Purpose: To describe the attributes of patients with Rasmussen's encephalitis (RE) seen in a tertiary epilepsy referral center in southern India and to enquire factors helpful in predicting responsiveness to immunotherapy.Methods: We diagnosed RE based on the European consensus criteria. To assess the factors that Could potentially predict the natural course and therapeutic Outcome, we subcategorized our patients according to age at onset ( 6 years), duration from onset to presentation ( 2 years), immunotherapy versus surgery, and early (<= 2 years from the onset) versus late Surgery.Results: The median age at disease onset of 19 patients was 6.0 years (range 2.3-13 years). Epilepsia partialis continua (EPC) and hemiparesis were noted in 14 (73.6%) and 16 (84.2%) patients, respectively. One patient, who presented with clysarthria due to tongue EPC, did not have hemiparesis despite having had the disease for over 15 years. The MRI findings in majority conformed to stage 3 of Bien classification. While 9/10 patients treated by surgery achieved seizure-freedom, only 1/11 patients who received immunotherapy did so. One patient expired due to subsequent development of contralateral hemispheric disease following successful hemispherectomy. None of the factors Such as age at onset, age at presentation, presence/absence of antecedents, seizure burden, MRI stage predicted responsiveness to immunotherapy.Conclusion: This study from a developing country, in addition to Substantiating the well known characteristics of RE, noted the following unusual findings: isolated lingual EPC abolished by focal cortical resection, bilateral RE, putaminal atrophy and absence of hemiparesis despite long standing disease. (C) 2009 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.Item Reversible periictal MRI abnormalities: Clinical correlates and long-term outcome in 12 patients(EPILEPSY RESEARCH, 2007)Although a wide spectrum of reversible periictal magnetic resonance imaging (MRI) abnormalities (RPMA) are being increasingly identified, the clinicians are often in a dilemma about their localization significance. This prompted us to analyze the clinical, MRI, electroencephalographic (EEG) and follow-up data of 12 patients with RPMA seen in a tertiary referral epilepsy center. RPMA occurred after a single or a cluster of focal seizures with or without secondary generalization. The interictal and ictal EEG abnormalities were localized to the site of RPMA in nine patients. RPMA involved areas remote from the site of EEG abnormalities in four patients. We have developed a comprehensive classification to account for the wide spectrum of RPMA involving gray matter, white matter and teptomeninges with or without contrast enhancement or mass effect. Follow-up MRIs showed complete resolution of RPMA in all, except in four patients, who developed residual focal atrophy. During median follow-up period of 3 years, recurrence of RPMA was observed in two patients. Diffusion weighted MRI in two patients and histopathological finding in one patient favored causal rote of hypoxia in the pathogenesis of RPMA. Our observations help to understand the electroclinical profile, radiological spectrum, localization significance and natural history of RPMA better. (c) 2006 Elsevier B.V. All rights reserved.