Analysis of neoplastic lesions in magnetic resonance imaging using self-organizing maps.

OBJECTIVE: To provide an improved method for the identification and analysis of brain tumors in MRI scans using a semi-automated computational approach, that has the potential to provide a more objective, precise and quantitatively rigorous analysis, compared to human visual analysis. BACKGROUND: Self-Organizing Maps (SOM) is an unsupervised, exploratory data analysis tool, which can automatically domain an image into selfsimilar regions or clusters, based on measures of similarity. It can be used to perform image-domain of brain tissue on MR images, without prior knowledge. DESIGN/METHODS: We used SOM to analyze T1, T2 and FLAIR acquisitions from two MRI machines in our service from 14 patients with brain tumors confirmed by biopsies--three lymphomas, six glioblastomas, one meningioma, one ganglioglioma, two oligoastrocytomas and one astrocytoma. The SOM software was used to analyze the data from the three image acquisitions from each patient and generated a self-organized map for each containing 25 clusters. RESULTS: Damaged tissue was separated from the normal tissue using the SOM technique. Furthermore, in some cases it allowed to separate different areas from within the tumor--like edema/peritumoral infiltration and necrosis. In lesions with less precise boundaries in FLAIR, the estimated damaged tissue area in the resulting map appears bigger. CONCLUSIONS: Our results showed that SOM has the potential to be a powerful MR imaging analysis technique for the assessment of brain tumors.

Extreme Spindles and Leukoencephalopathy after Acute Lymphoblastic Leukemia Treatment: An Undescribed Association.

We report a case of a child whose EEG demonstrated extreme spindles (ES) after acute lymphoblastic leukemia treatment. This finding has not been reported previously. In 1962, Gibbs and Gibbs described the ES EEG pattern due to its high amplitude (200 to 400 µV). ES are a rare spindle variant that is found in EEGs of 0.05% of normal children (average age, 3 years, with a range of 1 to 12 years), and are even rarer after 11 years. Moreover due to changes in the white matter of the frontal lobe, ES have been associated with such conditions as cerebral palsy and mental retardation, residual brain damage, undefined infections, infantile neuroaxonal dystrophy, Menkes' kinky-hair syndrome, congenital muscular dystrophy, hydrocephalus, porencephaly, epilepsy, progressive cerebellar degeneration, and mycoplasma encephalitis. Methotrexate has a notably toxic effect on the central nervous system, with leukoencephalopathy being the most common form. In our case, frontocentral ES were associated with hyperintense lesions in the white matter of the frontal lobe. Lesional deafferentation can be the substrate for an almost continuous ES, since both initiation and termination of spindle oscillations are thought to originate in thalamocortical neurons. Thus, we postulate that in some cases a partial functional cortical differentiation could generate ES.

Pharmacovigilance in epileptic patients using antiepileptic drugs.

OBJECTIVE: To investigate the occurrence of adverse effects of antiepileptic drugs (AED) in chronic epileptic patients in mono or polytherapy. METHOD: We evaluated consecutive patients that met the following inclusion criteria: age of 18 years or older, diagnosis of epilepsy for at least one year, stable dose of AED for at least three months. Patients were asked if they had any adverse event related to the AED. After that, they were interviewed according to a detailed semi-structure questionnaire. We also assessed specifically the adverse events in the last four weeks. The data were analyzed regarding the use of monotherapy x polytherapy, and the presence of probable depression (score>15) according to the Center for Epidemiologic Studies Depression Scale. RESULTS: Sixty-five patients were evaluated, 35 women, mean age 38.3 years; 35 patients were in use of monotherapy and 35 in polytherapy. Only 45 (69.2%) patients spontaneously reported adverse effects. After the formal questionnaire, 63 (97%) patients referred experiencing an adverse event (p<0.001). Seventeen men had adverse events, as opposed to 28 women (p=0.042). When the last four weeks were evaluated, patients with probable depression presented adverse events more frequently (p<0.0001). CONCLUSION: Our data suggest that adverse events are highly prevalent when a detailed questionnaire is applied and that depression may aggravate the number and intensity of side effects in patients using AEDs.

Pharmacovigilance in epileptic patients using antiepileptic drugs

OBJECTIVE: To investigate the occurrence of adverse effects of antiepileptic drugs (AED) in chronic epileptic patients in mono or polytherapy. METHOD: We evaluated consecutive patients that met the following inclusion criteria: age of 18 years or older, diagnosis of epilepsy for at least one year, stable dose of AED for at least three months. Patients were asked if they had any adverse event related to the AED. After that, they were interviewed according to a detailed semi-structure questionnaire. We also assessed specifically the adverse events in the last four weeks. The data were analyzed regarding the use of monotherapy x polytherapy, and the presence of probable depression (score >15) according to the Center for Epidemiologic Studies Depression Scale. RESULTS: Sixty-five patients were evaluated, 35 women, mean age 38.3 years; 35 patients were in use of monotherapy and 35 in polytherapy. Only 45 (69.2 percent) patients spontaneously reported adverse effects. After the formal questionnaire, 63 (97 percent) patients referred experiencing an adverse event (p<0.001). Seventeen men had adverse events, as opposed to 28 women (p=0.042). When the last four weeks were evaluated, patients with probable depression presented adverse events more frequently (p<0.0001). CONCLUSION: Our data suggest that adverse events are highly prevalent when a detailed questionnaire is applied and that depression may aggravate the number and intensity of side effects in patients using AEDs.