PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Contrast Media”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMedDate not supplied

Contrast-enhanced 3D-TOF MRA of peripheral vessels: intravascular versus extracellular MR contrast media.

MR contrast media have been used to improve MR angiography (MRA). Their effect has been particularly beneficial for extracranial MRA. This study evaluated the efficacy of a new formulation of ultrasmall superparamagnetic iron oxide particles (USPIO) on three-dimensional (3D) time of flight (TOF) MRA in the pelvis and lower limb circulation. Each of six dogs received 3 mg/kg of USPIO and .2 mmol/kg of gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) bis-methylamide (BMA) by intravenous infusion on separate examinations. Precontrast and postcontrast 3D-TOF MRA images of the lower extremities were acquired over the course of 45 minutes postinjection. Signal intensity (SI) was measured on axial views along the external iliac, femoral, and popliteal arteries. USPIO provided clear demarcation of the major primary, secondary, and tertiary vessels and the improved contrast-to-noise ratio (CNR) was maintained for 45 minutes. Gd-DTPA-BMA provided less signal enhancement than USPIO. The increase in CNR with this agent had significantly declined by 15 minutes after injection. The major vessels could no longer be visualized at 30 and 45 minutes after injection of Gd-DTPA-BMA This study demonstrates the efficacy of USPIO as a contrast medium for 3D-TOF MRA. It was concluded that USPIO provided effective and persistent enhancement of the peripheral vessels.

Animals↗
PubMedDate not supplied

Modification of platelet aggregation and thromboxane synthesis by intravascular contrast media.

Radiographic contrast media (RCM) decreased significantly platelet aggregation in human platelet-rich plasma (PRP) after addition of arachidonic acid (AA) or adenosine diphosphate (ADP). Unlike hypertonic saline, diatrizoate, ioxaglate, and iopamidol (40 and 160 mM) inhibited AA-induced aggregation. One hundred sixty mM ioxaglate inhibited slightly the concomitant formation of immunoreactive thromboxane B2 (TXB2). The ionic RCM ioxaglate (40 and 160 mM) and diatrizoate (160 mM), but not the nonionic iopamidol, decreased the ADP-induced aggregation more than hypertonic saline. When PRP was incubated with different RCM without any aggregating agents or with ADP, the formation of TXB2 was negligible. Results of this study show that inhibition of AA- and ADP-induced platelet aggregation by RCM is partly due to hypertonicity and partly related to the chemical structure of the RCM molecule. The inhibition of AA-induced aggregation is not caused by the lack of formation of aggregatory TXA2.

Adenosine Diphosphate↗
PubMed1991

Prediction of severe adverse reactions to ionic and nonionic contrast media in Japan: evaluation of pretesting. A report from the Japanese Committee on the Safety of Contrast Media.

In a nationwide prospective study of adverse reactions to intravenous contrast media (CM), the Japanese Committee on the Safety of Contrast Media compared high-osmolar ionic CM with low-osmolar nonionic CM. A total of 337,647 cases were analyzed. The reliability of pretesting with an intravenous injection of a small amount of CM as a means of predicting severe or fatal reactions was also evaluated. The predictive values of the pretest were 1.2% for ionic and 0.0% for nonionic CM, and the sensitivity values were 3.7% and 0.0%, respectively. Such low values render this test meaningless for predicting which patients are at risk of a severe adverse reaction. A comparison of the incidence of severe adverse reactions between the nonpretested and pretested patients, as well as between the nonpretested and pretested patients with negative results, disclosed no statistically significant differences. Also, no beneficial effects of premedication in patients with a positive pretest were proved. The authors therefore conclude that pretesting with an intravenous injection of a small amount of CM is not useful in predicting severe reactions to ionic or nonionic CM.

Contrast Media↗
PubMed1991

Heparin pharmacokinetics and in vitro anticoagulant activity in patients receiving nonionic radiographic contrast media.

Nonionic radiographic contrast media are used frequently in diagnostic and interventional angiography. However, there is concern that they may possess thrombogenic properties, and some studies have suggested that patients receiving nonionic contrast media are difficult to systemically anticoagulate with intravenous heparin. To investigate the potential effects of nonionic contrast media on systemic anticoagulation during diagnostic cardiac catheterization, pharmacokinetics and in vitro anticoagulant activity following a 3,000 U intravenous heparin bolus were assessed in 12 patients assigned randomly to either an ionic or a nonionic contrast agent. Independent of contrast agent, all patients exhibited biphasic (nonlinear) heparin pharmacokinetics characterized by an initial rapid disappearance phase, followed by a second slower phase. Each patient achieved a therapeutic plasma heparin concentration (greater than or equal to 0.2 U/ml) within 10 min of receiving the bolus, and maintained this level throughout the procedure. Heparin anticoagulant activity, as estimated by a standard activated partial thromboplastin time (APTT) was not affected differently by nonionic as compared with ionic contrast media (p greater than 0.05). Each patient rapidly achieved a level of systemic anticoagulation commonly considered therapeutic (APTT greater than or equal to 1.5 times the control), and maintained this level throughout the procedure. In both groups, APTT correlated directly with plasma heparin concentration (r = 0.95; p less than 0.0001), and inversely with the total amount of contrast media used during the procedure (r = -0.25; p = 0.01). Plasma heparin concentration did not correlate with total contrast media (r = -0.16; p greater than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Coagulation↗
PubMed1992

Nephrotoxicity of contrast media following cardiac angiography: pathogenesis, clinical course, and preventive measures, including the role of low-osmolality contrast media.

OBJECTIVE: To review the incidence, definition, clinical course, risk factors, pathogenesis and prevention of contrast-associated nephropathy (CAN) following cardiac angiography with emphasis on differences between high-osmolality contrast media (HOCM) and low-osmolality contrast media (LOCM). DATA SOURCES: Investigations in animal models and in patients following cardiac angiography. DATA EXTRACTION: Animal models of the pathogenesis of CAN are presented. Human studies describing the incidence, clinical course, risk factors, and prevention of CAN are reviewed. Comparative clinical trials of HOCM (diatrizoate, metrizoate) and LOCM (iohexol, iopamidol, ioxaglate) nephrotoxicity following cardiac angiography are critically evaluated. DATA SYNTHESIS: All clinical studies comparing CAN of HOCM versus LOCM following cardiac angiography have some methodologic limitations (e.g., small sample size, lack of control for other factors) that may affect renal function, lack of stratification for other reported risk factors, and variable or short follow-up periods. CONCLUSIONS: Whether the incidence of CAN following cardiac angiography is reduced with LOCM remains controversial. The incidence of CAN in patients with normal renal function does not appear to differ in patients treated with LOCM versus HOCM because few patients in each group develop renal failure. Additional controlled clinical trials comparing CAN of LOCM and HOCM in patients with renal dysfunction are needed. Because of greater product cost and scarcity of documented benefit compared with HOCM, selection of LOCM based on the presence of renal dysfunction cannot be recommended at this time.

Animals↗
PubMed2005

[Sonographic detection of kidney infarctions using ultrasound contrast media].

UNLABELLED: Contrast-enhanced CT is currently the gold standard for the diagnosis of kidney infarction. Particularly in patients with renal insufficiency, however, the use of iodine contrast media is limited. Sonographic examination using ultrasound contrast media may be an alternative for these patients. CASE REPORTS: We examined three patients with suspected ischaemic kidney infarction with ultrasound contrast media. Scanning was performed with low mechanical index, and SonoVue was used as by contrast-enhancing agent. In all three patients, kidney infarctions were clearly shown. In two patients, the lesions were confirmed by contrast-enhanced CT, in one no CT was performed because of impaired renal function. CONCLUSION: Kidney infarctions can reliably be detected by contrast-enhanced ultrasound using SonoVue as contrast agent. This is particularly valuable in patients with renal impaired renal function and other contraindications against iodine contrast media.

Aged↗
PubMed1980

Effect of contrast media on femoral blood flow. Comparison between non-ionic and ionic monomeric and monoacidic dimeric contrast media in the dog.

Injections of non-ionic monomeric (metrizamide, C29 and iohexol) and monoacidic dimeric (ioxaglate) contrast media into the femoral artery of dogs caused significantly less increase in the rate of femoral blood flow than the more hypertonic ionic monomeric compound metrizoate at equivalent iodine concentrations. The effect of metrizoate was similar to that of equiosmolal solutions of sodium chloride. Sodium chloride in concentrations equiosmolal with the non-ionic monomers and monoacidic dimer caused less changes in blood flow than these contrast media, but the changes in blood were equal to those of isotonic sodium chloride.

Animals↗
PubMed1980

Effects of contrast media on aortic endothelium. Experiments in the rat with non-ionic monomeric and monoacidic dimeric contrast media.

Injury to the aortic endothelium in rats was evaluated under a light microscope by a silver staining method after application of ionic monomeric (diatrizoate and metrizoate), non-ionic monomeric (C29 with different pH and buffers, 593, iohexol and metrizamide) and monoacidic dimeric (ioxaglate) contrast media, and iso- and hypertonic solutions of sodium chloride. In iodine equivalent concentrations the ionic monomers were significantly more toxic than the other contrast media. No significant was found between the non-ionic monomers, monoacidic dimer and sodium chloride solutions equiosmolal to the ionic monomers. Isotonic saline was the least harmful solution.

Animals↗
PubMed1980

The risk of arachnoiditis from experimental nonionic contrast media.

Aqueous myelographic contrast media are needed that are less expensive and better tolerated than metrizamide. This study compares two new, nonionic aqueous contrast media, ioglunide and iopamidol, with two previously developed contrast media, metrizamide and iocarmate. Myelography was performed with one of the contrast media in monkeys; four weeks later the degree of arachnoid fibrosis was determined in each animal by myelographic and histologic studies of the dural sac. Iopamidol, ioglunide, and metrizamide produced no more arachnoid changes than were found in the control animals. Iocarmate produced moderate to severe arachnoiditis.

Animals↗
PubMed2001

The use of dilute Calogen as a fat density oral contrast medium in upper abdominal computed tomography, compared with the use of water and positive oral contrast media.

AIM: Oral contrast media are commonly given prior to computed tomography (CT) examination of the upper abdomen. Although positive oral contrast media are normally used, there is increasing interest in using negative agents such as water and less commonly fat density products. The aim of this study was to compare a positive oral contrast medium, water, and a diluted emulsion of arachis oil Calogen, a fat density food supplement) for assessment of the upper abdomen. MATERIALS AND METHODS: Seventy-one patients referred for upper abdominal CT were randomized to receive either 500 ml water, 2% sodium diatrizoate or a dilute suspension of Calogen. The CT images were scored independently by three radiologists. Distension and anatomical identification was assessed for the stomach, duodenum and jejunum; with anatomical identification recorded for the pancreas, retroperitoneum, liver, gallbladder and spleen. RESULTS: Dilute Calogen produced a significant improvement (P < 0.01) in distension and anatomical visualization of the stomach and proximal duodenum. Only minimal differences were demonstrated between the three contrast media for visualization of more distal small bowel or identification of the other upper abdominal viscera. Significantly more artifacts were caused by positive contrast media than with the Calogen mixture. CONCLUSION: A dilute suspension of Calogen as an oral contrast medium is recommended when disease is suspected within the stomach or proximal duodenum.

Artifacts↗
PubMed1995

[A method of image enhancement in the use of hydrosoluble uro-angiographic contrast media].

The radiographic contrast, when using hydrosoluble uro-angiographic contrast media, depends on several factors. A phantom and a new method are proposed to assess and optimize the contrast. The phantom allows to simulate three pseudovessels with diameter of 2 mm, 5 mm, and 10 mm, placed in a water-equivalent layer of 20/cm thickness. The phantom is exposed to a photon beam produced by a conventional X ray tube, and the images are obtained using conventional screen film system. The aim of the study is to assess the radiographic contrast between the vessel and the background when modifying the optical density of the radiograph (by different settings of the mAs switching), the X-ray tube high voltage and the diameter of the vessels; the contrast was studied with four different contrast media (Uromiro 24%, Conray 36%, Iopamiro 300 and Iomeron 400) and three X-ray tube high voltages (60 kV, 80 kV, 100 kV). The curve fitting the contrast as a function of the optical density of the background (in each condition of high voltage, diameter of the vessel and contrast media used) is a parabola. A quite narrow distribution of abscissas of the maxima of the parabolas was found, ranging from the minimum optical density 1.21 in the case of 100 kV high voltage and 2 mm diameter to the maximum optical density 1.58 in the case 60 kV and 10 mm. The mean value (1.40) is proposed as the optical density of the background optimizing the contrast according to the screen-film system used. In conclusion, the authors suggest to optimize the use of contrast media, trying to obtain radiographs with an optical density approaching the optimal value in any clinical situation. Therefore tables of the settings of the X-ray tube and generator are required; the tables must take into account the main parameters influencing the settings, such as the source-film distance, the water-equivalent thickness of the patient and the film-screen system used.

Angiography↗
PubMed1984

[Improved identification of details in double-contrast studies of the stomach using a new mixture of contrast media].

In a contrast medium study, 100 patients were employed for a comparison between the contrast medium Mikropaque liquid and a mixture of Mikropaque HD and Mikropaque liquid in double-contrast examination of the stomach. The special feature of this method was that one and the same stomach was examined in each case with both contrast media. The new contrast media mixture with Mikropaque HD represents a step forward; the contrast could be enhanced in 80% of the cases, and the finely contoured relief became visible in two-thirds of the cases, compared with one-third of the examined patients before this method was introduced.

Contrast Media↗