Biomedical subjects
Publications and source records attributed to P N Jayakumar.
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.
INTRODUCTION: Acute disseminated encephalomyelitis (ADEM) is usually a monophasic illness characterized by multiple lesions involving gray and white matter. Quantitative MR techniques were used to characterize and stage these lesions. METHODS: Eight patients (seven males and one female; mean age 19 years, range 5 to 36 years) were studied using conventional MRI (T2- and T1-weighted and FLAIR sequences), diffusion-weighted imaging (DWI) and proton magnetic resonance spectroscopy (MRS). Apparent diffusion coefficient (ADC) values and MRS ratios were calculated for the lesion and for normal-appearing white matter (NAWM). Three patients were imaged in the acute stage (within 7 days of the onset of neurological symptoms) and five in the subacute stage (after 7 days from the onset of symptoms). RESULTS: ADC values in NAWM were in the range 0.7-1.24 x 10(-3) mm/s2 (mean 0.937 +/- 0.17 mm/s2). ADC values of ADEM lesions in the acute stage were in the range 0.37-0.68 x 10(-3) mm/s2 (mean 0.56 +/- 0.16 mm/s2) and 1.01-1.31 x 10(-3) mm/s2 (mean 1.24 +/- 0.13 mm/s2) in the subacute stage. MRS ratios were obtained for all patients. NAA/Cho ratios were in the range 1.1-3.5 (mean 1.93 +/- 0.86) in the NAWM. NAA/Cho ratios within ADEM lesions in the acute stage were in the range 0.63-1.48 (mean 1.18 +/- 0.48) and 0.29-0.84 (mean 0.49 +/- 0.22) in the subacute stage. The ADC values, NAA/Cho and Cho/Cr ratios were significantly different between lesions in the acute and subacute stages (P < 0.001, P < 0.027, P < 0.047, respectively). ADC values were significantly different between lesions in the acute (P < 0.009) and subacute stages (P < 0.005) with NAWM. In addition, NAA/Cho and Cho/Cr ratios were significantly different between lesions in the subacute stage and NAWM (P < 0.006, P < 0.007, respectively). CONCLUSION: ADEM lesions were characterized in the acute stage by restricted diffusion and in the subacute stage by free diffusion and a decrease in NAA/Cho ratios. Restricted diffusion and progressive decrease in NAA/Cho ratios may help in staging the disease.
OBJECTIVE: To examine the volumetric and metabolic correlates of caudate nucleus in antipsychotic-naïve schizophrenia patients in comparison with healthy controls. METHOD: Twelve antipsychotic-naïve schizophrenia patients and 13 healthy controls underwent (31)P magnetic resonance spectroscopy of basal ganglia. Magnetic resonance imaging volume of caudate nuclei was measured using scion image software. RESULTS: Patients had significantly smaller caudate volume than healthy controls. Phosphocreatine (PCr)/total phosphorous and PCr/total adenosine tri-phosphate ratios of both caudate nuclei were significantly lower in patients than controls. Significant negative correlation was found between the left caudate volume and left PCr/total phosphorus ratio in the patients. Age at onset of psychosis had i) significant negative correlation with right and left caudate volumes and ii) significant positive correlation with left PCr/total phosphorus ratio. CONCLUSION: The metabolic and volumetric abnormalities of caudate nucleus in antipsychotic-naïve schizophrenia patients support neurodevelopmental etiopathogenesis.
Tumor-specific alterations at the RB1 gene locus in 30 human vestibular schwannomas including 10 NF2 and 20 sporadic cases were analysed. Southern blot analysis of DNA from these samples revealed loss of heterozygosity (LOH) at the RB1 locus in 6 of 24 informative cases (25%) compared to normal blood DNAs from the same patients. Northern blot analysis showed normal size RB1 mRNA in all the tumor samples. However, there was a 2-5-fold increase in the level of expression of the RB1 gene in all the tumor samples compared to the WI38 cell line which was used as control. Western blot analysis of the RB1 protein, pRb showed a 2.5-5-fold increase in the level of total pRb as compared to normal WI38 cell line. Sixty five to seventy five percent of the total pRb were in phosphorylated form in most tumors. The LOH at the RB1 gene locus suggests genetic instability in these patients. Further, increased levels of RB1 mRNA, total pRb and the phosphorylated form of pRb suggests that RB1 gene in these tumors may have anti-apoptotic function. These results suggest that the RB1 gene has a major role in the development of human vestibular schwannomas.
OBJECTIVE: This study used 31-phosphorus magnetic resonance spectroscopy ((31)P MRS) to investigate basal ganglia abnormalities in neuroleptic-naive patients with schizophrenia. METHOD: Nineteen schizophrenia patients and 31 age- and sex-matched healthy comparison subjects underwent (31)P MRS. RESULTS: The phosphocreatine/total phosphorus and phosphocreatine/total ATP ratios in both basal ganglia were significantly lower in patients. CONCLUSIONS: Schizophrenia patients showed features of increased metabolism in the basal ganglia consistent with impaired activity of the frontostriatal pathways.
Tuberous sclerosis (TS) is an autosomal dominant disease that affects the brain, skin, eye, heart and kidney. The diagnostic criteria for tuberous sclerosis complex (TSC) have recently been revised. There are relatively few Indian studies on this disorder. Twenty-six patients diagnosed as having TS over a period of 18 years are being reported. The onset of seizures ranged from infancy to adolescence. The patterns of epilepsy encountered were generalized tonic clonic seizures (13), complex partial seizures (10), simple partial seizures (9) and myoclonic jerks (4) including infantile spasms (3). Patients often had more than one seizure type. Nineteen patients were mentally subnormal. Cutaneous manifestations were facial angiofibroma i.e. adenoma sebaceum (20), shagreen patches (7), hypopigmented macules (6), ash leaf spots (4), café-au-lait spots (2), facial hypoplasia (2) and periungual fibromas (1). One patient each had retinal phakoma and renal angiomyolipoma. CT scan revealed sub-ependymal calcifications (12), parenchymal tubers (3), cerebral edema (3) and cortical atrophy (1). One patient had enhancement of peri-ventricular sub-ependymal lesions on MRI. Anticonvulsants prescribed were phenobarbitone (20), diphenyl hydantoin (14), carbamazepine (8), sodium valproate (4), benzodiazepines (4), ACTH (2), prednisone (1), mysoline (1) and vigabatrin (1). Most patients were on combinations of anti-convulsants and response to therapy was usually not very satisfactory. However, the child treated with vigabatrin did well.
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.
OBJECTIVE: Studies of Neurological Soft Signs (NSS) in schizophrenia are confounded by handedness, inconsistent methodology, and prior treatment with neuroleptics. The study objective is to examine NSS in never-treated schizophrenia. METHOD: We examined the NSS in treatment-naïve schizophrenia patients (n = 21) and age, sex, education, and handedness matched normal controls (n = 21) using the modified Neurological Evaluation Scale with good inter-rater reliability. RESULTS: Schizophrenia patients had significantly more NSS than normals. No significant correlation was found between illness duration and NSS. CONCLUSION: Higher neurological signs in never-treated patients and their lack of association with illness duration suggest neurodevelopmental etiopathogenesis of schizophrenia.
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.
BACKGROUND: Corpus Callosum (CC) abnormalities have been described in schizophrenia. Review of CC measurement methods in schizophrenia reveals inconsistency and lack of neuroanatomical basis. AIMS: The aims of the study are to describe a new CC measurement method with valid a neuroanatomical and cytoarchitectural basis and to demonstrate inter-rater reliability for the same. SETTINGS AND DESIGN: The study was performed in the National Institute of Mental Health & Neurosciences, Bangalore, India. Ours is a cross-sectional study in which both the first author and senior neuroradiologist were blind to clinical details. MATERIAL AND METHODS: We report a reliable, semi-automated CC measuring technique with a neuroanatomical and cytoarchitectural basis tested in a group of 16 never-treated schizophrenia patients using 1-mm thick, objectively defined midsagittal MRI section. Measurement on coded slices using scion image software ensured elimination of rater bias. STATISTICAL ANALYSIS USED: The statistical analysis used for assessing inter-rater reliability is intraclass correlation coefficient analysis. RESULTS: The intraclass correlation coefficients for the CC measurements were as follows: CC Area = 0.93; Anterior CC area = 0.84; Area of body of the CC = 0.83; Area of CC isthmus = 0.65; Area of CC splenium = 0.88; maximum antero-posterior distance of CC = 0.96. CONCLUSION: Measurements showed good inter-rater reliability. The methodology demonstrated in our study is simple, relevant, reliable and can be used for future schizophrenia research.
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.
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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.
Ossified ligamentum flavum is increasingly appreciated as an important cause of thoracic myeloradiculopathy. Fifteen patients with age ranging from 30-61 years were studied. Fourteen presented with spastic paraparesis, and radiculopathy was the only complaint in one patient. Routine skiagrams and myelograms showed non-specific changes. Baseline CT and CT myelogram, however, documented the ossification of ligamentum flavum comprehensively. MRI was done in three patients. Multiple levels of the disease were seen in two cases. Four patients had ossified posterior longitudinal ligament. Thickened ligamentum flavum should be considered as an important cause of thoracic cord compression.
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.
We report two patients with pure word deafness (PWD) with tumour in the III ventricle region with obstructive hydrocephalus. A diagnosis of PWD was made in these two patients in view of impaired verbal comprehension in the presence of adequate hearing, intact acoustic stapedius reflex and well preserved environmental sound perception. Return of verbal comprehension following the radiation therapy observed is probably due to the reduction of the tumour mass and the release of thalamocortical auditory pathways from its compressive effect. Our findings support the hypothesis of the presence of discrete auditory pathways for mediation of verbal and non-verbal stimuli independently.