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Philippe Pereira

Publications and source records attributed to Philippe Pereira.

5 recordsLinked to original sources
PubMed2006

Electrodes and multiple electrode systems for radio frequency ablation: a proposal for updated terminology.

OBJECTIVE: Research on technology for soft tissue radio frequency (RF) ablation is ever advancing. A recent proposal to standardize terminology of RF electrodes only deals with the most frequently used commercial electrodes. The aim of this study was to develop a logical, versatile, and unequivocal terminology to describe present and future RF electrodes and multiple electrode systems. MATERIALS AND METHODS: We have carried out a PubMed search for the period from January 1st 1990 to July 1st 2004 in seven languages and contacted the six major companies that produce commercial RF electrodes for use in the liver. In a first step, names have been defined for the five existing basic designs of single-shaft electrode. These names had to be unequivocal, descriptive of the electrode's main working principle and as short as possible. In a second step, these basic names have been used as building blocks to describe the single-shaft electrodes in combination designs. In a third step, using the same principles, a logical terminology has been developed for multiple electrode systems, defined as the combined use of more than one single-shaft RF electrode. RESULTS: Five basic electrode designs were identified and defined: plain, cooled, expandable, wet, and bipolar electrodes. Combination designs included cooled-wet, expandable-wet, bipolar-wet, bipolar-cooled, bipolar-expandable, and bipolar-cooled-wet electrodes. Multiple electrode systems could be characterized by describing several features: the number of electrodes that were used (dual, triple, etc.), the electric mode (monopolar or bipolar), the activation mode (consecutive, simultaneous or switching), the site of the inserted electrodes (monofocal or multifocal), and the type of single-shaft electrodes that were used. CONCLUSION: In this terminology, the naming ofthe basic electrode designs has been based on objective criteria. The short and unequivocal names of the basic designs can easily be combined to describe current and future combination electrodes. This terminology provides an exact and complete description of the versatile novel multiple electrode systems.

Catheter Ablation↗
PubMed2005

Electrodes and multiple electrode systems for radiofrequency ablation: a proposal for updated terminology.

Research on technology for soft tissue radiofrequency (RF) ablation is ever advancing. A recent proposal to standardise terminology of RF electrodes only deals with the most frequently used commercial electrodes. The aim of this study was to develop a logical, versatile and unequivocal terminology to describe present and future RF electrodes and multiple electrode systems. We have carried out a PubMed search for the period from January 1 1990 to July 1 2004 in seven languages and contacted the six major companies that produce commercial RF electrodes for use in clinic. In a first step, names have been defined for the five existing basic designs of single-shaft electrode. These names had to be unequivocal, descriptive of the electrode's main working principle and as short as possible. In a second step, these basic names have been used as building blocks to describe the single-shaft electrodes in combination designs. In a third step, using the same principles, a logical terminology has been developed for multiple electrode systems, defined as the combined use of more than one single-shaft RF electrode. Five basic electrode designs were identified and defined: plain, cooled, expandable, wet and bipolar electrodes. Combination designs included cooled-wet, expandable-wet, bipolar-wet, bipolar-cooled, bipolar-expandable and bipolar-cooled-wet electrodes. Multiple electrode systems could be characterised by describing several features: the number of electrodes that were used (dual, triple, ...), the electric mode (monopolar or bipolar), the activation mode (consecutive, simultaneous or switching), the site of the inserted electrodes (monofocal or multifocal), and the type of single shaft electrodes that were used. In this terminology, the naming of the basic electrode designs has been based on objective criteria. The short and unequivocal names of the basic designs can easily be combined to describe current and future combination electrodes. This terminology provides an exact and complete description of the versatile novel multiple electrode systems.

Catheter Ablation↗
PubMed2004

Clinical evaluation of a computer simulated prediction model of contrast enhancement of the liver in spiral CT.

OBJECTIVE: A software program was developed simulating a compartmental model of blood circulation based on differential equations. The aim of this study was to compare software-simulated levels of hepatic enhancement with the true values in patients and to test how many patients reach the simulated hepatic enhancement level. METHODS: As software program the CT application software carebolus 2 (Siemens, Forchheim, Germany) was used. Hepatic contrast-enhancement curves were simulated prior to CT examinations to evaluate a patient specific time delay after contrast application. At the time delay, when the simulation curve showed an enhancement threshold of 40 Hounsfield Units (HU), the CT spiral scan was started applying 120 ml contrast media with 2 ml/s. The simulated curves were compared with the empiric curves of each patient. RESULTS: 25 of 28 patients (89%) achieved 40 HU. The mean enhancement of empiric patients curves was 46.32 +/- 11.9 HU, the mean simulated enhancement was 46.62 +/- 4.3 HU S.D. (P= 0.48). 4.4 values per patient liver could be compared with the simulation curve (122 points for 28 patients): 50% of the patient curves were within a range of 5 HU compared with the simulation curve. CONCLUSION: Software simulation of contrast enhancement curves of the liver is a feasible and valuable method to predict individual liver enhancement curves. Improvements concerning the integration of cardiovascular parameters and preexisting liver parenchymal diseases into the simulation software have to be arranged.

Adult↗
PubMed2003

Application of poly-lactide-co-glycolide-microspheres in the transarterial chemoembolization in an animal model of hepatocellular carcinoma.

AIM: To introduce an animal model of hepatocellular carcinoma (HCC) in ACI-rats, and to evaluate the therapeutic effects of Poly-lactide-co-glycolide (Plcg) -microspheres in the transarterial chemoembolization (TACE) in this model, as well the value of this model in the experiments of interventional therapy. METHODS: Subcapsular implantation of a solid Morris Hepatoma 3 924A (1 mm(3)) in the livers was carried out in 11 male ACI-rats. The tumor volume (V1) was measured by magnetic resonance imaging (MRI) (13 days after implantation). After laparotomy and retrograde placement of catheter into the gastroduodenal artery (14 days after implantation), the following protocols of interventional treatment were performed: (A) mitomycin C+Poly-lactide-co-glycolide (Plcg)-microspheres (n=4); (B) 0.9 % NaCl (control group, n=7). 13 days after these therapies the change of the tumor volume (V2) was determined by MRI again. RESULTS: The success rate of tumor implantation reached to 100 %. The mean tumor volume before TACE (V1) were 0.082 cm(3) in group A and 0.096 cm(3) in group B respectively. The mean tumor volume after TACE (V2) were 0.230 cm(3) in group A and 1.347 cm(3) in group B respectively. The mean V2/V1 were 2.860 in group A and 27.120 in group B respectively. Compared to the control group (group B), groups A showed a significant reduction of tumor growth (P=0.004) in the period of observation. CONCLUSION: The growth of liver tumor could be obviously prevented by utilizing Plcg-mitomycin-microspheres in TACE in animal model. This rat model of HCC is suitable for the experimental studies of interventional therapy.

Animals↗