Biomedical subjects
Publications and source records attributed to S G Srikanth.
INTRODUCTION: Canavan disease is a megalencephalic leukodystrophy due to deficiency of the enzyme aspartoacylase. Proton MR spectroscopy finding of elevated N-acetyl-L: -aspartate is considered diagnostic of Canavan disease. CASE REPORT: We report a case of Canavan disease, which showed restricted diffusion in diffusion-weighted imaging and discuss the cause of it.
BACKGROUND AND AIMS: Tuberculous meningitis (TBM) is a debilitating form of CNS tuberculosis with a high morbidity and mortality in spite of treatment. The diagnosis is based on clinical, radiological and laboratory features. The classical CT features of basal exudates, hydrocephalus, infarcts and granulomas have been mostly reported in younger individuals. Our aim was to study imaging features of TB meningitis in adults over the age of 50 years. MATERIALS AND METHODS: Clinical, imaging and laboratory features of 53 adult patients over the age of 50 years (sixth to eighth decades) were studied retrospectively. Diagnosis of TBM was based on clinical and laboratory features. RESULTS: Imaging features were the conspicuous absence of typical features of TBM (ie, basal meningeal enhancement, hydrocephalus, infarcts/granulomas were seen in only a minority of patients). CONCLUSIONS: CT features of TBM in elderly patients were few, atypical and non-contributory for diagnosis, probably because of age related immune senescence. Strong clinical suspicion and correlation with laboratory findings is necessary for early diagnosis.
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Ehlers-Danlos Syndrome (EDS) is more identified for its cutaneous features but its neurological manifestations have not received the focused attention. Four patients of Ehlers-Danlos Syndrome (EDS) with neurological manifestations were evaluated for phenotypic data. These four men were from three families and two had consanguineous parentage. The mean age at onset and presentation of neurological symptoms were 10.5 years and 19 years respectively. Patient 1 presented with bilateral optic atrophy, sensorineural deafness, cerebellar ataxia and neuropathy. Patient 2 had marfanoid habitus, chorea and cerebellar ataxia. Patient 3 had action and percussion myotonia, wasting and weakness of sternocleidomastoid and distal limb muscles. Patient 4 had action myotonia, mirror movements of both hands and neuropathy. MRI of brain showed right parietal polymicrogyria. Neuroaxis involvement at multiple levels in EDS may have prognostic significance.
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Racemose cysticercal cyst is the subarachnoid manifestation of the larvae of Taenia solium. On MRI the cysts may resemble other cystic masses. We report the magnetic resonance spectroscopy (MRS) features of a case on in vivo proton spectroscopy and discuss its role in the diagnosis of intracranial cysts of parasitic aetiology.
Persistent mirror movements are unwanted movements restricted to muscles homologous to those moved intentionally on the opposite body half. It is rarely observed and the functional MRI findings in a case of persistent mirror movement are described.
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare, recently described disease. It is characterized clinically by a large head, mild neurological symptoms and a remarkably slow course of functional deterioration. The MRI is characterized by 'swollen white matter' and large symmetrical cystic changes in the cerebral hemispheres. MLC should be considered in the differential diagnosis of children with megalencephaly and leukoencephalopathy. We report a child with this disease and discuss the MRI and MRS features.
Although known, histologically proven pulmonary metastasis from a benign intracranial meningioma is exceedingly rare. We report a case of meningiothelial meningioma producing a solitary pulmonary deposit.
Intracranial metastases of central nervous system are relatively common in patients with systemic cancer. Computed tomography (CT) scans of 60 patients of intracranial metastatic disease of unknown primaries, at the time of surgery, were retrospectively analyzed. These patients primarily presented with neurological dysfunction. They were operated upon for various reasons and histopathological diagnosis was obtained. There were 39 male and 21 female patients, with age range of 18 to 74 years. The common clinical symptoms were raised intracranial pressure without lateralization, acute onset hemiplegia and seizures. Multiple cranial nerve palsies were observed in 4 patients. Histopathologically the intracranial lesions consisted of metastatic adenocarcinoma (32 cases) or metastatic squamous cell carcinoma (28 cases). Among cases of adenocarcinoma, CT revealed solitary lesions in 17 and multiple lesions in 13 cases. Two had extraaxial deposition in the region of petrous apex. Out of squamous cell carcinomas, 17 lesions were solitary, while 10 were multiple and one had extraaxial deposition in the region of petrous apex. This study is unique as it consisted of CT features of intracranial metastases of unknown primary malignant disease elsewhere in the body.
A 56 year old man presented with acute onset posterior column and lateral spinothalamic tract dysfunction over a period of 15 days. MRI showed diffuse hyperintensity on T2WI involving the posterior columns. A diagnosis of subacute combined degeneration (SCD) of the spinal cord was considered and confirmed by laboratory findings. The patient showed complete recovery on B12 therapy. MRI lesion also compeletely resolved.
PURPOSE: To determine the utility of 3D steady-state MR cisternography in the demonstration and localisation of cerebrospinal fluid (CSF) leak in patients with clinically suspected CSF rhinorrhoea. MATERIAL AND METHODS: Six consecutive patients with clinically suspected CSF rhinorrhoea were examined with routine MR evaluation and MR cisternography (MRC). All MR examinations included fast spin-echo (SE) T1WI in axial and sagittal planes, fast SE T2WI in axial and coronal planes and fluid attenuated inversion recovery (FLAIR) images in the axial plane. 3D evaluation was done using the CISS technique with 0.7-mm thickness in the sagittal and coronal planes. The site and extent of the defect, and any brain herniation detected on MRC were correlated with surgical findings. RESULTS: In the 6 patients who underwent surgical exploration and repair, intraoperative findings correlated with the defect revealed by MRC in all cases. CONCLUSION: In clinically suspected CSF rhinorrhoea, MRC is highly accurate in localising the site and extent of CSF fistula and may be used as the first investigation due to its efficacy and non-invasive nature.
Infective intracranial aneurysms are relatively uncommon. They develop due to septic embolisation of the vasa vasorum or lumen of the artery, with resultant focal arteritis and necrosis, leading to aneurysm formation. They are an important cause for intracranial haemorrhage. Six cases of infective aneurysms are described. A focus of infection could be detected in all the patients. Surgery was done in three cases, out of which two patients made significant recovery, while one patient died in the immediate postoperative period. Out of the three cases, treated conservatively with antibiotic therapy, there was total resolution on follow up angiogram in two, while one patient was lost to follow up.
Intramedullary epidermoid cysts of the spinal cord are rare tumours, especially those not associated with spinal dysraphism. Around 50 cases have been reported in the literature. Of these, only seven cases have had magnetic resonance imaging studies. We report two cases of spinal intramedullary epidermoid cysts with MR imaging. Both were not associated with spina bifida. In one patient the tumour was located at D4 vertebral level, while in other within the conus medullaris. The clinical features, MR imaging characteristics and surgical treatment of such rare intramedullary benign tumours are discussed, and the relevant literature reviewed.
Two patients with isolated schizencephaly, a very rare congenital anomaly of the brain, who presented with epilepsy are presented. According to imaging morphology, there are two types of schizencephaly, 'open lip' and 'minimally open lip'. These two cases emphasize that while MRI is superior to CT in the diagnosis of congenital brain anomalies, schizencephaly can be diagnosed by its characteristic CT features.
Moyamoya disease (MMD) is an uncommon entity outside Japan. Though the clinical and radiological features are well described, involvement of the posterior circulation has not been highlighted. Out of 10 patients of MMD studied, the posterior circulation was involved in 9 (3 bilateral, 6 unilateral). The P1 segment was most commonly affected. Interestingly, no infarcts were seen in the territory of the posterior circulation in any patient. Five patients showed recent haemorrhages on scan. It was thalamic haemorrhage in four and subarachnoid in one patient. The posterior circulation is frequently involved in MMD as evident on angiography. However, ischaemic events of the posterior circulation are not frequent, as the posterior circulation acts as collateral pathway for the diseased anterior circulation till later stages of the disease.
A 46 year old male presented with a cerebellopontine angle syndrome. CT scan and MRI revealed a cystic mass with a solid nodule in the cerebellopontine angle. At surgery, a vascular lesion was encountered which was totally excised in two stages. The histopathology was consistent with that of a cavernous malformation. Only four such cases have been reported so far in the English literature. The clinical and radiological features and the surgical management are discussed.