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At least 415 records · Page 23Linked to original sources
PubMed2004

Contrast-enhanced MR Angiography of the renal arteries: blinded multicenter crossover comparison of gadobenate dimeglumine and gadopentetate dimeglumine.

PURPOSE: To prospectively and intraindividually compare 0.1 mmol/kg gadobenate dimeglumine with 0.2 mmol/kg gadopentetate dimeglumine for contrast material-enhanced magnetic resonance (MR) angiography of the renal arteries. MATERIALS AND METHODS: Institutional review board approval was granted by each of three participating centers. The study accorded with international standards for good clinical practice and Declaration of Helsinki and subsequent amendments. Patients gave written informed consent before enrollment. Patients (n = 34) underwent two MR angiographic examinations more than 48 hours but less than 12 days apart. Gadobenate dimeglumine followed by gadopentetate dimeglumine was administered in 18 patients; the order of administration was reversed in 16 patients. A 1.5-T MR imager was used with a phase-encoded three-dimensional spoiled breath-hold pulse sequence. Two blinded independent readers qualitatively assessed randomized subtracted maximum intensity projection images. A three-point scale for diagnostic quality (0, poor; 1a or 1p, moderate; and 2a or 2p, adequate [a and p refer, respectively, to absence and presence of vascular lesions]) was used to score each of nine segments of the abdominal aorta and both renal arteries (possible overall score, 18). Quantitative assessment (vessel signal-to-noise ratio [SNR], vessel-muscle contrast-to-noise ratio [CNR]) of source images was performed for regions of interest in supra-, juxta-, and infrarenal aorta segments and psoas muscle. Data were tested with analysis of variance for two-period crossover design. Interreader agreement was evaluated with Cohen kappa statistics. RESULTS: No difference in mean image quality between the two contrast agents was observed; scores for gadobenate dimeglumine and gadopentetate dimeglumine were 15.15 and 15.23 for reader 1 and 16.77 and 17.01 for reader 2. The order of contrast material administration likewise produced no quality differences: readers 1 and 2 reported scores of 14.4 +/- 4.2 (standard deviation) and 16.7 +/- 2.3, respectively, when gadobenate dimeglumine was given first, and 15.2 +/- 1.8 and 16.6 +/- 1.6, respectively, when gadopentetate dimeglumine was given first. Results of quantitative evaluation showed increasing SNR and CNR with gadobenate dimeglumine in segments at progressively lower levels of the aorta, but increases in SNR and CNR at the infrarenal aorta (48.3 vs 40.6 and 44.2 vs 36.4, respectively) were not significant (P = .05 for both). CONCLUSION: Gadobenate dimeglumine at a dose of 0.1 mmol/kg is comparable to gadopentetate dimeglumine at 0.2 mmol/kg for contrast-enhanced renal MR angiography.

Adult↗
PubMed2005

Acute liver rejection: accuracy and predictive values of doppler US measurements--initial experience.

PURPOSE: To prospectively evaluate accuracy and predictive values of Doppler ultrasonographic (US) measurement of portal blood velocity (PBV) and splenic pulsatility index (SPI) in diagnosis of clinically relevant acute rejection in patients with clinicobiochemical hepatic dysfunction after orthotopic liver transplantation (OLT). MATERIALS AND METHODS: Study was approved by the institutional review board, and protocol conformed to ethical guidelines of Declaration of Helsinki. Patient informed consent was obtained. In 27 patients with OLT (23 men, four women; mean age, 48 years; range, 27-64 years), PBV and SPI were measured at Doppler US within 48 hours before or after liver biopsy for clinically suspected acute rejection. Biopsy specimens were assigned scores according to Banff method, and rejection activity index (RAI) was calculated. RAI score of 4 or greater was considered clinically relevant acute rejection. Doppler US parameters were analyzed as absolute values and as percentage point changes with respect to values obtained at last examination before rejection was suspected. Information from two Doppler US parameters was combined; Doppler US composite index was calculated. Statistical tests were conducted to assess accuracy, sensitivity, specificity, and predictive values of Doppler US parameters in diagnosis of graft rejection. RESULTS: Clinically relevant acute rejection was diagnosed in nine patients. Median time from OLT until histologic diagnosis of acute rejection was 8 days (range, 5-20 days). Rejection was associated with a marked reduction in mean PBV (-43% +/- 5 [standard error of the mean]) and a slight increase in SPI (+12% +/- 16). The calculated Doppler US composite index was strictly related to severity of rejection (P < .001). When applied retrospectively, this index had good accuracy (88%) for prediction of rejection (specificity, 89%; sensitivity, 86%; negative predictive value, 94%). CONCLUSION: During the first weeks after OLT, a marked decrease in PBV associated with increased SPI supports suspicion of clinically relevant acute rejection.

Acute Disease↗
PubMed2005

Personal computer versus workstation display: observer performance in detection of wrist fractures on digital radiographs.

PURPOSE: To retrospectively compare the accuracy of observer performance with personal computer (PC) compared with that with dedicated picture archiving and communication system (PACS) workstation display in the detection of wrist fractures on computed radiographs. MATERIALS AND METHODS: This study was conducted according to the principles of the Declaration of Helsinki (2002 version) of the World Medical Association. The institutional clinical board approved the study; informed consent was not required. Seven observers independently assessed randomized anonymous digital radiographs of the wrist from 259 subjects; 146 had fractures, and 113 were healthy control subjects (151 male and 108 female subjects; average age, 33 years). Follow-up radiographs and/or computed tomographic scans were used as the reference standard for patients with fractures, and follow-up radiographs and/or clinical history data were used as the reference standard for controls. The PC was a standard hospital machine with a 17-inch (43-cm) color monitor with which Web browser display software was used. The PACS workstation had two portrait 21-inch (53-cm) monochrome monitors that displayed 2300 lines. The observers assigned scores to the radiographs on a scale of 1 (no fracture) to 5 (definite fracture). Receiver operating characteristic (ROC) curves, sensitivity, specificity, and accuracy were compared. RESULTS: The areas under the ROC curves were almost identical for the PC and workstation (0.910 vs 0.918, respectively; difference, 0.008; 95% confidence interval: -0.029, 0.013). The average sensitivity with the PC was almost identical to that with the workstation (85% vs 84%, respectively), as was the average specificity (82% vs 81%, respectively). The average accuracy (83%) was the same for both. CONCLUSION: The results of this study showed that there was no difference in accuracy of observer performance for detection of wrist fractures with a PC compared with that with a PACS workstation.

Adult↗
PubMed2006

Hepatic metastases: detection with multi-detector row CT, SPIO-enhanced MR imaging, and both techniques combined.

PURPOSE: To retrospectively compare the accuracy in detection of hepatic metastases among contrast material-enhanced multi-detector row computed tomography (CT) alone, superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging alone, and a combination of contrast-enhanced CT and SPIO-enhanced MR imaging. MATERIALS AND METHODS: The ethics committee did not require its approval or informed consent for this retrospective study, which was compliant with Declaration of Helsinki principles. Data in 38 patients (22 men, 16 women; mean age, 64.5 years; range, 35-78 years) suspected of having hepatic metastases who underwent both contrast-enhanced CT and SPIO-enhanced MR imaging were retrospectively analyzed. Twenty-one of the 38 patients had 61 metastases. Seventeen of the 61 metastases were confirmed histologically; the remaining 44 metastases were defined with imaging follow-up. At MR imaging, SPIO-enhanced heavily T1-weighted images, T2*-weighted gradient echo images, and T2-weighted fast spin-echo images were evaluated. Contrast-enhanced multi-detector row CT images obtained in the portal phase were evaluated. Four blinded observers independently reviewed CT images, MR images, and the combination of CT and MR images. Diagnostic accuracy was evaluated by using the alternative free-response receiver operating characteristic (AFROC) method. Sensitivities and positive predictive values were also analyzed with the Fisher protected least significant difference test and generalized estimating equations. RESULTS: The mean area under the AFROC curve for the combined approach (0.70) was significantly higher than that for SPIO-enhanced MR imaging alone (0.58, P < .05, Fisher protected least significant difference test), and there was no significant difference between each of them and that for contrast-enhanced CT alone (0.66). For all lesions, the mean sensitivity of combined imaging (0.59) was significantly higher than that of CT (0.48) or MR imaging (0.43) alone (P < .05, Fisher protected least significant difference test and generalized estimating equations). For all lesions, the mean positive predictive values were 0.82, 0.89, and 0.81, for combined MR and CT, CT alone, and MR alone, respectively. CONCLUSION: The addition of SPIO-enhanced MR imaging to contrast-enhanced multi-detector row CT (ie, combined analysis of SPIO-enhanced MR images and contrast-enhanced CT images) can improve sensitivity in the detection of hepatic metastases, although this improvement in sensitivity was not significant at AFROC analysis.

Adult↗
PubMed2006

Myocardial tissue phase mapping with cine phase-contrast mr imaging: regional wall motion analysis in healthy volunteers.

PURPOSE: To establish prospectively a database of normal three-dimensional systolic and diastolic endocardial and epicardial velocity values for all myocardial segments in healthy volunteers by using cine phase-contrast velocity magnetic resonance imaging, also called tissue phase mapping (TPM). MATERIALS AND METHODS: The study was approved by the institutional ethics committee and was conducted according to principles of the Declaration of Helsinki; each subject provided informed written consent. Ninety-six healthy volunteers (57 [59%] men, 39 [41%] women; mean age, 38 years +/- 12 [standard deviation]) underwent cardiac phase-contrast imaging with a black blood segmented k-space gradient-echo sequence for the analysis of three-dimensional myocardial velocity with high spatial resolution at 1.5 T on basal, midventricular, and apical short-axis views. Eighteen consecutive volunteers were imaged twice to determine interstudy reproducibility, and intra- and interobserver variability values were analyzed. Systolic and diastolic velocity curves were analyzed for peak velocity and time to peak velocity in the radial, circumferential, and longitudinal directions, as well as for torsion rate and longitudinal strain rate. Mixed-effects models with a random intercept for volunteers were used to test differences among the three ventricular sections and the transmural, endocardial, and epicardial parameters. RESULTS: TPM enabled reproducible assessment of myocardial velocity with small intra- and interobserver variability values. Systolic peak radial velocity was lowest at the apical level (P < .001); diastolic peak radial velocity was similar at all three myocardial levels (P = .73). As viewed from the apex, a relative counterclockwise rotation during systole was followed by a relative clockwise rotation of the apex against the base. Diastolic and systolic peak longitudinal velocity values decreased from base to apex (P < .001). A gradient between endocardium and epicardium was observed for radial velocity values, with greater endocardial velocity values (P < .001). CONCLUSION: TPM is a reproducible comprehensive modality for assessment of regional wall motion, and intra- and interobserver variability values are low.

Adult↗
PubMed1998

Good clinical research practice: what is it and is it possible in the intensive care unit?

With the growing quest for answers to vexing dilemmas in critically ill patients, more intensive care units are embarking on clinical research. This places increasing importance on Good Clinical Research Practice (GCRP), a set of guidelines drawn up by the Pharmaceutical Industry to assist investigators in conducting ethical, reliable scientific studies. GCRP is a combination of good basic management skills allied to ethical principles for scientific research. Based on the principles of the Declaration of Helsinki, it consists of three tenets: patient protection (ethics), credible data (science) and data control. This article describes GCRP specifically relating it to the intensive care situation, illustrating some of the concepts with practical examples. With a minimum of extra time and effort these basic principles can be integrated as routine into all research projects.

Clinical Trials as Topic↗
PubMed2000

Participation of children in clinical trials: UK, European and international legal perspectives on consent.

The Declaration of Helsinki was, until recently, the leading international code on the conduct of clinical trials on human subjects. The Council of Europe's Convention on Human Rights and Biomedicine (1997) and the ICH guidelines for Good Clinical Practice (1996) represent a significant step towards increased harmonization of standards in the conduct of medical experiments on human subjects. But in spite of emerging areas of consensus, there remain important areas of unclarity and divergence. Medical practitioners involved in paediatric research in the UK are concerned about the lack of certainty in the law, particularly on the application of consent rules to emergency research. This paper examines UK, European and International norms on the participation of children in medical research and compares the circumstances under which consent rules may be waived under each normative regime.

Child↗
PubMed1994

Ethics and research in nursing.

Considering the importance of research in the development of nursing, we examine the ethical principles governing nurses' investigative activity, as well as the different codes regulating biomedical investigation with human beings, amongst which are the Nuremberg Code, the Declaration of Human Rights, and the Declaration of Helsinki. From the perspective of the central points of the article reference is made to different codes proposed by international nursing associations, as well as reviewing the Deontological Code of Spanish Nursing. The ethical principles a nurse has to bear in mind in research are analysed, with respect to patients, society and the profession. Finally, we refer to certain ethical aspects to be considered in the elaboration and development of a research project, as well as publication of the results.

Codes of Ethics↗