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Biomedical subjects

J Piqueras

Publications and source records attributed to J Piqueras.

At least 19 recordsLinked to original sources
PubMed2005

Effects of capsule endoscopy on cardiac pacemakers.

BACKGROUND AND STUDY AIMS: Capsule endoscopy is a new, noninvasive diagnostic technique which enables visualization of the mucosa of the small intestine in physiological conditions and without the need to subject the patient to external radiation. Wireless capsule video endoscopy is contraindicated in patients with a cardiac pacemaker. However, on the basis of the characteristics of the radiofrequency band used by the endoscopic capsule, together with a series of other factors, it is possible that the patient's use of a pacemaker should not be a contraindication to capsule endoscopy. PATIENTS AND METHODS: This work had two phases: an in vitro study, using an interference detector, and an in vivo study involving 20 patients with cardiac pacemakers who showed symptoms or signs that justified a capsule endoscopy investigation. RESULTS: No interference was observed during the first, in vitro, phase of the study. In the second phase, patients wore a Holter recorder for a mean time of 10 hours, during which the average number of recorded QRS complexes exceeded 30,000. All the pacemakers functioned normally. Interference due only to myopotentials was detected in a single patient in whom modification of the pacemaker programming was necessary. In the other 19 patients, neither sensing nor stimulation failures were observed. CONCLUSIONS: No interference between the pacemaker and the endoscopic capsule was observed. All the pacemakers functioned normally, and no increased incidence of adverse effects was observed. Neither was any pacemaker-induced interference observed on the capsule endoscopy images.

Aged↗
PubMed2003

Validation of the Coulter LH 750 in a hospital reference laboratory.

Validation of the Coulter LH 750 was carried out in our central hospital laboratory, which processes 1500 hemograms per day for patients admitted into the 4 hospitals of our hospital complex and their corresponding outpatient departments. It is the reference laboratory for the provincial health care area. The analytical quality and the practical use of the instrument were studied, and we obtained within- and between-run imprecision estimates with reference controls of between 0.24% and 2.56% and inaccuracies of between -1.32% and 3.07% for basic hemogram parameters. Similar results were obtained with specimens from patients, with imprecision estimates between 0.56% and 2.56%. Linearity estimates were between 0.3 x 10(9)/L and 380 x 10(9)/L for leukocytes and between 3 x 10(9)/L and 1900 x 10(9)/L for platelets. The instrument evaluation was completed with a study of interference by bilirubin, lipemia, hemolysis, platelet clumps, and heparin and an examination of other variables, including carryover, detection limits, and the correlation of results with those of the Coulter Gen-S. A special evaluation was made of the new erythroblast count feature; with reference controls, imprecision estimates for this count were 10% to 12%, and with patient specimens imprecision averaged 10.39% up to 4 erythroblasts per 100 leukocytes. We also studied the correlation of LH 750 results and interferences with those of the manual reference method. Finally, National Committee for Clinical Laboratory Standards protocols were used to test for suspect and confirmation flags in leukocyte differential counts for 258 specimens representative of our routine. The practicability of the analyzer was studied in terms of technical difficulty, speed, and cost; also evaluated were new software elements for validation by source clinic and pathology and for reference values based on age. In conclusion, we analyzed the impact and improvements that may be expected in our laboratory (a user of Technicon and Coulter instruments) from introducing the new LH 750 analyzer into our routine.

Blood Cell Count↗
PubMed2000

The RETAIN project: DICOM teleradiology over an ATM-based network. Radiological Examinations Transfer on an ATM Integrated Network.

The RETAIN project (Radiological Examinations Transfer on an ATM Integrated Network) has aimed at testing videoconferencing and DICOM image transfers to get advice about difficult radiological cases over an asynchronous transfer mode (ATM)-based network, which affords a more comfortable interface than narrow-band networks and allows exchange of complete image series using the DICOM format of studies. For this purpose, an experimental ATM network was applied between six university hospitals in four different countries. An assessment of the functionalities of the system was performed by means of log-file analysis, video recording of the sessions and forms filled out by the participants at the end of each session. Questionnaires were answered by the users at the end of the project to bring out perspectives of utilisation and added value. We discussed 43 cases during 20 sessions. For technical or organisational problems, only 20 of the 36 planned sessions took place. The throughput over ATM (10.5 Mbit/s, 20 times faster than six ISDN B-channels) was adequate. Despite the experimental configuration of the network, the system was considered as satisfactory by all the physicians. In 72 % of the sessions, the expected result (answer to the question) was gained. By common consent, videoconferencing was unanimously regarded as a prominent tool in improving the interaction quality. Asynchronous transfer mode is an efficient method for fast transferring of radiologic examinations in DICOM format and for discussing them through high-quality videoconferencing.

Computer Communication Networks↗
PubMed2000

Low-dose high-resolution CT of the chest in children and young adults: dose, cooperation, artifact incidence, and image quality.

OBJECTIVE: The radiation dose, artifact incidence, and image quality of high-resolution chest CT examinations performed with standard and low doses and patient cooperation were investigated in children and young adults. SUBJECTS AND METHODS: Three successive controlled studies were conducted in different groups of children and young adults, totaling 203 patients. Dosimetry of high-resolution CT was performed at 180, 50, and 34 mAs in three groups of 25 patients. Streak artifact incidence using alternating 50- and 34-mAs slices was assessed and correlated with patient compliance with breath-holding commands in 44 children. Image quality was evaluated in scans obtained with 34 versus 180 mAs in cooperative patients (n = 42) and in scans obtained with 50 versus 180 mAs in noncooperative patients (n = 42). Artifacts and image quality were assessed by controlled repeated interpretations. RESULTS: Radiation dose was 5.4+/-1.6 mSv for 180 mAs, 1.5+/-0.5 mSv for 50 mAs, and 1.1+/-0.3 mSv for 34 mAs. Cooperation was obtained in 66% of the patients. Artifacts were more frequently seen in scans of noncooperative patients (30%) and in 34-mAs scans (47%); the highest incidence was found using 34 mAs in noncooperative patients (60%, p = 0.02). No differences in image quality scores were seen in scans obtained with 50 mAs versus those obtained with 180 mAs in noncooperative patients (p<0.05), and small differences were found in scans obtained with 34 mAs versus those obtained with 180 mAs in cooperative patients for fissures (p = 0.005) and peripheral structures (p = 0.02). CONCLUSION: Low-dose high-resolution CT provided a significant reduction in radiation dose (72% for 50 mAs and 80% for 34 mAs) and good-quality images of the lung when performed with 50 mAs in noncooperative and 34 mAs in cooperative pediatric and young adult patients.

Adolescent↗
PubMed1996

[Test of a teleradiology network based on ATM (asynchronous transfer mode)].

The retain project (Radiological Examination Transfer on ATM Integrated Network) consisted in teleradiology trials focused on pediatric imaging between two university hospitals. Rennes (France) and Barcelona (Spain) using an integrated broadband communication network based on ATM (asynchronous transfer mode), as part of a European research program. The network used was a full 10 Mbits/s ATM network directly connected to local PACSs (medical imaging hospital networks). One important reason to explicitly consider ATM for medical imaging is that multimedia applications on such networks allow integration of digital data and person-to-person communication. The utility of broadband communication for teleradiology has been confirmed. High quality video and sound are important for both human communication and medical video transfer. The project led to guidelines regarding technical options still open to improvement.

Computer Communication Networks↗
PubMed1993

Data interface between a radiology information system and a computed radiography system using a personal computer and standard software.

We describe the implementation of a simple data interface between a radiology information system and a computed radiography system that uses personal computers and standard software. The radiology information system was developed in house and runs in a local area network of personal computers. The computed radiography system is connected to a picture archiving and communication system. We have implemented a software data interface on a microcomputer, allowing automated transfer of patient data from the radiology information system program to the computed radiography scheduling program. The interface adds essential information used by the picture archiving and communication system to handle work lists, routing, and archiving algorithms. We have improved the user interface, shortened the scheduling time, enabled coherence of data bases, and eased the use of computed radiography and examination routing in the picture archiving and communication system. We have been using this interface for more than 1 year without difficulties. This custom solution addresses the problem of interconnecting existing equipment, avoiding proprietary restrictions or the lack of effective standards. This approach can be applied to any radiology environment that uses personal computers.

Humans↗
PubMed1992

[Resistance to antivitamins K].

Resistance to oral anticoagulant is a rare phenomenon. We report the case of a 32-year-old woman who required anticoagulation due to a deep venous thrombosis. She gradually developed resistance to acenocumarol and warfarin. Although the HPLC (high performance liquid chromatography) method proved satisfactory acenocumarol levels in plasma, therapeutic anticoagulation was not achieved. The mechanisms of resistance are discussed.

Acenocoumarol↗
PubMed1989

Fatal mushroom poisoning in Barcelona, 1986-1988.

In 1986-88, 46 poisonings (4 of which were fatal) caused by amatoxin mushroom were reported. The fatalities were males aged between 7 and 65 years. They all had gastrointestinal symptoms and three of the patients died of acute hepatic insufficiency. The fourth died as a result of an intestinal perforation. The clinical and pathological alterations are compared with the findings of other authors.

Adolescent↗
PubMed1989

Hepatotoxic mushroom poisoning: diagnosis and management.

Hepatotoxic mushroom poisoning (due to Amanita, Lepiota and Galerina species) may be considered as a real medical emergency, since an early diagnosis and immediate treatment are required for a successful outcome. In this review the physio-pathological features and the clinical picture of amatoxin poisonings are described as the basis for diagnosis and therapeutic decisions. The treatment schedule proposed is analyzed in some points: Symptomatic and supportive measures, toxin removal and extraction procedures, and the possibility of using antidotes. Some parameters with prognostic significance are commented on. Finally, the mortality rate and its evolution throughout the present century is also considered.

Amanitins↗
PubMed1989

Arachnoid cysts with intracystic and subdural haematoma.

Two cases of arachnoid cysts with acute intracystic and subdural haematomas are described. CT examination was performed in both cases, and showed a hyperdense expansion with thinning of the inner table of the skull. The different ways in which subdural haematomas associated with arachnoid cysts may be seen on CT are discussed.

Adolescent↗