Supporting content-based image retrieval and computer-aided diagnosis systems with association rule-based techniques

In this work, we take advantage of association rule mining to support two types of medical systems: the Content-based Image Retrieval (CBIR) systems and the Computer-Aided Diagnosis (CAD) systems. For content-based retrieval, association rules are employed to reduce the dimensionality of the feature vectors that represent the images and to improve the precision of the similarity queries. We refer to the association rule-based method to improve CBIR systems proposed here as Feature selection through Association Rules (FAR). To improve CAD systems, we propose the Image Diagnosis Enhancement through Association rules (IDEA) method. Association rules are employed to suggest a second opinion to the radiologist or a preliminary diagnosis of a new image. A second opinion automatically obtained can either accelerate the process of diagnosing or to strengthen a hypothesis, increasing the probability of a prescribed treatment be successful. Two new algorithms are proposed to support the IDEA method: to pre-process low-level features and to propose a preliminary diagnosis based on association rules. We performed several experiments to validate the proposed methods. The results indicate that association rules can be successfully applied to improve CBIR and CAD systems, empowering the arsenal of techniques to support medical image analysis in medical systems. (C) 2009 Elsevier B.V. All rights reserved.

Day-night pattern of autonomic nervous system modulation in patients with heart failure with and without sleep apnea

Introduction: Among patients with congestive heart failure (CHF) both obstructive and central sleep apnea (SA) are associated with increased sympathetic activity. However, the day-night pattern of cardiac autonomic nervous system modulation in CHF patients with and without sleep apnea is unknown. Material and methods: Twenty-five CHF patients underwent polysomnography with simultaneous beat-to-beat blood pressure (Portapres), respiration and electrocardiogram monitoring. Patients were divided according to the presence (SA, n=17) and absence of SA (NoSA, n=8). Power spectral analyses of heart rate variability (HRV) and spontaneous baroreflex sensitivity (BRS) were determined in periods with stable breathing while awake at 6 AM, 10 AM, 10 PM, as well as during stage 2 sleep. In addition, muscle sympathetic nerve activity (MSNA) was evaluated at 10 AM. Results: RR variance, low-frequency (LF), high-frequency (HF) powers of HRV, and BRS were significantly lower in patients with SA compared with NoSA in all periods. HF power, a marker of vagal activity, increased during sleep in patients with NoSA but in contrast did not change across the 24-hour period in patients with SA. MSNA was significantly higher in patients with SA compared with NoSA. RR variance, LF and HF powers correlated inversely with simultaneous MSNA (r=-0.64, -0.61, and -0.61 respectively; P < 0.01). Conclusions: Patients with CHF and SA present a reduced and blunted cardiac autonomic modulation across the 24-hour period. These findings may help to explain the increased cardiovascular risk in patients with CHF and SA. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

Monitoring of protein catabolism in neonates and young infants post-cardiac surgery

Aims: To evaluate cell catabolism by balance of nitrogen and phosphate, and creatinine excretion in children post-cardiac surgery; to establish protein and energy requirements to minimize catabolism; and to assess nutritional therapy by following these parameters and serial anthropometric measurements. Methods: A prospective observational study of children with congenital heart disease undergoing cardiac surgery. Blood samples and 24-h urine collections were obtained postoperatively for creatinine measurement and nitrogen and phosphate balance. Anthropometric measurements (weight, mid-arm muscle circumference and triceps skinfold thickness) were obtained preoperatively and at paediatric intensive care unit and hospital discharge. Results: Eleven children were studied for 3-10 postoperative days. Anabolism was associated with higher protein and energy intakes compared to catabolism (1.1 vs. 0.1 g/kg/day and 54 vs. 17 kcal/kg/day, respectively). On days with anabolism, phosphate balance was greater compared with that on days with catabolism. Daily creatinine excretion did not correlate with protein balance. Anthropometric measurements did not change significantly over time. Conclusions: Children with congenital heart disease undergoing cardiac surgery achieved anabolism with > 55 kcal/kg/day and > 1 g/kg/day of protein. Balance of phosphate was useful to monitor cell breakdown. Anthropometric measurements were not valuable to evaluate nutritional therapy in this population.

The ACB technique: a biomagentic tool for monitoring gastrointestinal contraction directly from smooth muscle in dogs

The aim of this paper was to verify whether AC biosusceptometry (ACB) is suitable for monitoring gastrointestinal (GI) contraction directly from smooth muscle in dogs, comparing with electrical recordings simultaneously. All experiments were performed in dogs with magnetic markers implanted under the serosa of the right colon and distal stomach, and their movements were recorded by ACB. Monopolar electrodes were implanted close to the magnetic markers and their electric potentials were recorded by electromyography (EMG). The effects of neostigmine, hyoscine butylbromide and meal on gastric and colonic parameters were studied. The ACB signal from the distal stomach was very similar to EMG; in the colonic recordings, however, within the same low-frequency band, ACB and EMG signals were characterized by simultaneity or a widely changeable frequency profile with time. ACB recordings were capable of demonstrating the changes in gastric and colonic motility determined by pharmacological interventions as well as by feeding. Our results reinforce the importance of evaluating the mechanical and electrical components of motility and show a temporal association between them. ACB and EMG arecomplementary for studying motility, with special emphasis on the colon. ACB offers an accurate method for monitoring in vivo GI motility.

Options for monitoring diabetic cats

The key to successful long-term management of diabetes in cats is individualization of advice to suit cat and owner. A relationship based on trust and cooperation between veterinarian and client leads invariably to the most satisfactory outcome. Success requires knowledge of the options for monitoring diabetic cats, selection and adaptation of appropriate techniques for each individual case, and provision of ongoing support and guidance for owners. The ongoing treatment of a diabetic cat can be one of the more rewarding experiences of feline practice, and many diabetic cats and their owners come to occupy a special place within the clinic environment. This chapter provides a comprehensive overview of the current options for monitoring diabetes in cats and guidelines for application of the techniques to clinical cases.

Percutaneous Transatrial Access to the Pericardial Space for Epicardial Mapping and Ablation

Background-Puncture of the atrial appendage may provide access to the pericardial space. The aim of this study was to evaluate the feasibility of epicardial mapping and ablation through an endocardial transatrial access in a swine model. Methods and Results-An 8-F Mullins sheath was used to perforate the right (n=16) or left (n=1) atrial appendage in 17 pigs (median weight, 27.5 kg; first and third quartiles [Q1, Q3], 25.2, 30.0 kg). A 7-F ablation catheter was introduced into the pericardial space to perform epicardial mapping and deliver radiofrequency pulses on the atria. The pericardial space was entered in all 17 animals. In 15 (88%) animals, there was no hemodynamic instability (mean blood pressure monitoring, initial median, 80 mm Hg; Q1, Q3, 70, 86 mm Hg; final median, 88 mm Hg; Q1, Q3, 80, 96 mm Hg; P=0.426). In these 15, a mild hemorrhagic pericardial effusion was identified and aspirated (median, 20 mL; Q1, Q3, 15, 30 mL) during the procedure, and postmortem gross analysis revealed that the atrial perforation was closed in these animals. In 2 (12%) of the 17 animals, there was major pericardial bleeding with hemodynamic collapse. On gross examination, it was found that pericardial space was accessed through right ventricular perforation in 1 animal and the tricuspid annulus in the other. After the initial study, we used an occlusion device in 3 other animals to attempt to seal the puncture (2 at the right atrial appendage and 1 at the right ventricle). These 3 animals had no significant pericardial bleeding. Conclusions-Transatrial endovascular right atrial appendage puncture may provide a potential alternative route for pericardial access. Further studies are needed to evaluate its safety with longer and more-complex procedures before being applied in clinical settings. (Circ Arrhythm Electrophysiol. 2011;4:331-336.)

Nutrition Therapy in a Pediatric Intensive Care Unit: Indications, Monitoring, and Complications

Background: Nutrition therapy (NT) is essential for the care of critically ill children. Inadequate feeding leads to malnutrition and may increase the patient`s risk of morbidity and mortality. The aim of this study was to describe the NT used in a tertiary pediatric intensive care unit (PICU). Methods: The authors evaluated NT administered to 90 consecutive patients who were hospitalized for 7 days in the PICU of Instituto da Crianca, Hospital das Clinicas, Universidade de Sao Paulo, Brazil. NT was established according to the protocol provided by the institution`s NT team. NT provided a balance of fluids and nutrients and was monitored with a weekly anthropometric nutrition assessment and an evaluation of complications. Results: NT was initiated, on average, within 72 hours of hospitalization. Most children (80%) received enteral nutrition (EN) therapy; of these, 35% were fed orally and the rest via nasogastric or postpyloric tube. There were gastrointestinal complications in patients (5%) who needed a postpyloric tube. Parenteral nutrition (PN) was used in only 10% of the cases, and the remaining 10% received mixed NT (EN + PN). The average calorie and protein intake was 82 kcal/kg and 2.7 g/kg per day. Arm circumference and triceps skinfold thickness decreased. Conclusions: The use of EN was prevalent in the tertiary PICU, and few clinical complications occurred. There was no statistically significant change in most anthropometric indicators evaluated during hospitalization, which suggests that NT probably helped patients maintain their nutrition status. (JPEN J Parenter Enteral Nutr. 2011;35:523-529)