Automatic Small Bowel Tumor Diagnosis by Using Multi-Scale Wavelet-Based Analysis in Wireless Capsule Endoscopy Images

BACKGROUND: Wireless capsule endoscopy has been introduced as an innovative, non-invasive diagnostic technique for evaluation of the gastrointestinal tract, reaching places where conventional endoscopy is unable to. However, the output of this technique is an 8 hours video, whose analysis by the expert physician is very time consuming. Thus, a computer assisted diagnosis tool to help the physicians to evaluate CE exams faster and more accurately is an important technical challenge and an excellent economical opportunity. METHOD: The set of features proposed in this paper to code textural information is based on statistical modeling of second order textural measures extracted from co-occurrence matrices. To cope with both joint and marginal non-Gaussianity of second order textural measures, higher order moments are used. These statistical moments are taken from the two-dimensional color-scale feature space, where two different scales are considered. Second and higher order moments of textural measures are computed from the co-occurrence matrices computed from images synthesized by the inverse wavelet transform of the wavelet transform containing only the selected scales for the three color channels. The dimensionality of the data is reduced by using Principal Component Analysis. RESULTS: The proposed textural features are then used as the input of a classifier based on artificial neural networks. Classification performances of 93.1% specificity and 93.9% sensitivity are achieved on real data. These promising results open the path towards a deeper study regarding the applicability of this algorithm in computer aided diagnosis systems to assist physicians in their clinical practice.

The Arterial Switch Operation in Europe for Transposition of the Great Arteries: a Multi-Institutional Study from the European Congenital Heart Surgeons Association

OBJECTIVES: This study analyzes the results of the arterial switch operation for transposition of the great arteries in member institutions of the European Congenital Heart Surgeons Association. METHODS: The records of 613 patients who underwent primary arterial switch operations in each of 19 participating institutions in the period from January 1998 through December 2000 were reviewed retrospectively. RESULTS: A ventricular septal defect was present in 186 (30%) patients. Coronary anatomy was type A in 69% of the patients, and aortic arch pathology was present in 20% of patients with ventricular septal defect. Rashkind septostomy was performed in 75% of the patients, and 69% received prostaglandin. There were 37 hospital deaths (operative mortality, 6%), 13 (3%) for patients with an intact ventricular septum and 24 (13%) for those with a ventricular septal defect (P < .001). In 36% delayed sternal closure was performed, 8% required peritoneal dialysis, and 2% required mechanical circulatory support. Median ventilation time was 58 hours, and intensive care and hospital stay were 6 and 14 days, respectively. Although of various preoperative risk factors the presence of a ventricular septal defect, arch pathology, and coronary anomalies were univariate predictors of operative mortality, only the presence of a ventricular septal defect approached statistical significance (P = .06) on multivariable analysis. Of various operative parameters, aortic crossclamp time and delayed sternal closure were also univariate predictors; however, only the latter was an independent statistically significant predictor of death. CONCLUSIONS: Results of the procedure in European centers are compatible with those in the literature. The presence of a ventricular septal defect is the clinically most important preoperative risk factor for operative death, approaching statistical significance on multivariable analysis.

Interictal Spike EEG Source Analysis in Hypothalamic Hamartoma Epilepsy

Objective: The epilepsy associated with the hypothalamic hamartomas constitutes a syndrome with peculiar seizures, usually refractory to medical therapy, mild cognitive delay, behavioural problems and multifocal spike activity in the scalp electroencephalogram (EEG). The cortical origin of spikes has been widely assumed but not specifically demonstrated. Methods: We present results of a source analysis of interictal spikes from 4 patients (age 2–25 years) with epilepsy and hypothalamic hamartoma, using EEG scalp recordings (32 electrodes) and realistic boundary element models constructed from volumetric magnetic resonance imaging (MRIs). Multifocal spike activity was the most common finding, distributed mainly over the frontal and temporal lobes. A spike classification based on scalp topography was done and averaging within each class performed to improve the signal to noise ratio. Single moving dipole models were used, as well as the Rap-MUSIC algorithm. Results: All spikes with good signal to noise ratio were best explained by initial deep sources in the neighbourhood of the hamartoma, with late sources located in the cortex. Not a single patient could have his spike activity explained by a combination of cortical sources. Conclusions: Overall, the results demonstrate a consistent origin of spike activity in the subcortical region in the neighbourhood of the hamartoma, with late spread to cortical areas.

Analysis of the EEG Dynamics of Epileptic Activity in Gelastic Seizures Using Decomposition in Independent Components

Objective: Gelastic seizures are a frequent and well established manifestation of the epilepsy associated with hypothalamic hamartomas. The scalp EEG recordings very seldom demonstrate clear spike activity and the information about the ictal epilepsy dynamics is limited. In this work, we try to isolate epileptic rhythms in gelastic seizures and study their generators. Methods: We extracted rhythmic activity from EEG scalp recordings of gelastic seizures using decomposition in independent components (ICA) in three patients, two with hypothalamic hamartomas and one with no hypothalamic lesion. Time analysis of these rhythms and inverse source analysis was done to recover their foci of origin and temporal dynamics. Results: In the two patients with hypothalamic hamartomas consistent ictal delta (2–3 Hz) rhythms were present, with subcortical generators in both and a superficial one in a single patient. The latter pattern was observed in the patient with no hypothalamic hamartoma visible in MRI. The deep generators activated earlier than the superficial ones, suggesting a consistent sub-cortical origin of the rhythmical activity. Conclusions: Our data is compatible with early and brief epileptic generators in deep sub-cortical regions and more superficial ones activating later. Significance: Gelastic seizures express rhythms on scalp EEG compatible with epileptic activity originating in sub-cortical generators and secondarily involving cortical ones.

Analysis of the Generators of Epileptic Activity in Early-Onset Childhood Benign Occipital Lobe Epilepsy

Objective: The Panayiotopoulos type of idiopathic occipital epilepsy has peculiar and easily recognizable ictal symptoms, which are associated with complex and variable spike activity over the posterior scalp areas. These characteristics of spikes have prevented localization of the particular brain regions originating clinical manifestations. We studied spike activity in this epilepsy to determine their brain generators. Methods: The EEG of 5 patients (ages 7–9) was recorded, spikes were submitted to blind decomposition in independent components (ICs) and those to source analysis (sLORETA), revealing the spike generators. Coherence analysis evaluated the dynamics of the components. Results: Several ICs were recovered for posterior spikes in contrast to central spikes which originated a single one. Coherence analysis supports a model with epileptic activity originating near lateral occipital area and spreading to cortical temporal or parietal areas. Conclusions: Posterior spikes demonstrate rapid spread of epileptic activity to nearby lobes, starting in the lateral occipital area. In contrast, central spikes remain localized in the rolandic fissure. Significance: Rapid spread of posterior epileptic activity in the Panayitopoulos type of occipital lobe epilepsy is responsible for the variable and poorly localized spike EEG. The lateral occipital cortex is the primary generator of the epileptic activity.

A Idade é uma Variável Preditora da Funcionalidade após Acidente Vascular Cerebral? Um Estudo Multi-Análises

Existem diversos factores que podem influenciar o prognóstico funcional nos doentes com Acidente Vascular Cerebral (AVC), nomeadamente o hemisfério afectado, severidade do deficit neurológico inicial, presença de comorbilidades, etiologia, entre outros. A idade como factor preditivo na reabilitação destes doentes tem sido alvo de controvérsia. O objectivo deste trabalho foi avaliar a idade como variável preditiva de funcionalidade após AVC. Os autores recolheram retrospectivamente os dados dos processos clínicos dos doentes internados para reabilitação no Serviço de MFR do Hospital de Curry Cabral durante o ano de 2008, tendo como critério de inclusão diagnóstico de AVC. A funcionalidade foi avaliada à entrada e à saída do internamento, com a Medida de Independência Funcional (MIF) e o Índice de Barthel (IB). Os doentes com idade igual ou inferior a 45 anos foram considerados jovens adultos. Foi realizado o emparelhamento de doentes em casos-controlo. Para cada caso de AVC no adulto jovem os critérios de emparelhamento foram: idade> 45 anos, o mesmo tipo de AVC e hemisfério envolvido e igual MIF à entrada (mais ou menos três pontos). Para tratamento estatístico foi utilizado o programa SPSS 13.0. Foram recolhidos dados de 69 doentes com AVC, dos quais 12 foram considerados adultos jovens (38 +-5 anos). Quando comparados com os doentes mais velhos, os adultos jovens saíram com uma MIF maior (101 Vs 88 pontos; p=0,04), sem que se verificassem diferenças estatisticamente significativas em relação a: MIF à entrada, IB à entrada e saída, eficiência da MIF ou duração do internamento. A idade jovem associou-se com um melhor valor de MIF à saída (r=0,33, p=0,006), mesmo quando se controlou para a MIF à entrada (r=0,23, p=0,05). Em relação à análise dos nove pares caso-controlo, não se verificaram diferenças entre os grupos nas medidas de funcionalidade à entrada e à saída, nem na duração do internamento. A idade correlacionou-se com funcionalidade à saída, sendo que os doentes mais jovens saíram mais funcionais. No entanto, na análise caso-controlo, quando se controlou para outras variáveis (e.g. tipo de AVC), a variável perdeu o seu valor preditivo. Estes resultados podem dever-se ao facto de o AVC no jovem adulto ter diferentes características, como um maior número de eventos hemorrágicos. Nesta amostra, os jovens adultos tiveram igual número de AVC isquémicos e hemorrágicos (seis) e o grupo mais velho teve apenas 23% eventos hemorrágicos (p=0,07). É conhecido o melhor prognóstico funcional deste tipo de AVC, quando não associados a mortalidade precoce. Este estudo apresenta algumas limitações: o tamanho da amostra; o facto de a MIF e o IB não serem medidas de funcionalidade desenvolvidas especificamente para doentes com AVC; um viés de selecção, pois somente alguns doentes são incluídos em programa de reabilitação em internamento; o momento de avaliação da funcionalidade residual foi á saída do internamento, apenas algumas semanas pós-AVC. A idade jovem parece associar-se a um melhor prognóstico funcional. Este aspecto pode estar associado ao facto de o AVC nos doentes mais novos ter características diferentes (e.g. maior proporção de AVC hemorrágico), normalmente associadas a uma recuperação mais favorável.

Ocular Pulse Amplitude and Doppler Waveform Analysis in Glaucoma Patients

PURPOSE: To determine the correlation between ocular blood flow velocities and ocular pulse amplitude (OPA) in glaucoma patients using colour Doppler imaging (CDI) waveform analysis. METHOD: A prospective, observer-masked, case-control study was performed. OPA and blood flow variables from central retinal artery and vein (CRA, CRV), nasal and temporal short posterior ciliary arteries (NPCA, TPCA) and ophthalmic artery (OA) were obtained through dynamic contour tonometry and CDI, respectively. Univariate and multiple regression analyses were performed to explore the correlations between OPA and retrobulbar CDI waveform and systemic cardiovascular parameters (blood pressure, blood pressure amplitude, mean ocular perfusion pressure and peripheral pulse). RESULTS: One hundred and ninety-two patients were included [healthy controls: 55; primary open-angle glaucoma (POAG): 74; normal-tension glaucoma (NTG): 63]. OPA was statistically different between groups (Healthy: 3.17 ± 1.2 mmHg; NTG: 2.58 ± 1.2 mmHg; POAG: 2.60 ± 1.1 mmHg; p < 0.01), but not between the glaucoma groups (p = 0.60). Multiple regression models to explain OPA variance were made for each cohort (healthy: p < 0.001, r = 0.605; NTG: p = 0.003, r = 0.372; POAG: p < 0.001, r = 0.412). OPA was independently associated with retrobulbar CDI parameters in the healthy subjects and POAG patients (healthy CRV resistance index: β = 3.37, CI: 0.16-6.59; healthy NPCA mean systolic/diastolic velocity ratio: β = 1.34, CI: 0.52-2.15; POAG TPCA mean systolic velocity: β = 0.14, CI 0.05-0.23). OPA in the NTG group was associated with diastolic blood pressure and pulse rate (β = -0.04, CI: -0.06 to -0.01; β = -0.04, CI: -0.06 to -0.001, respectively). CONCLUSIONS: Vascular-related models provide a better explanation to OPA variance in healthy individuals than in glaucoma patients. The variables that influence OPA seem to be different in healthy, POAG and NTG patients.