Comparative rheology of low- and iso-osmolarity contrast agents at different temperatures

Stickiness of 7 types of iodinated contrast media used during interventional radiology and interventional cardiology procedures

INTRODUCTION

During Interventional Cardiology (IC) and Interventional Radiology (IR) procedures operators' gloves, guide wires and catheters may stick together due to the inherent stickiness of Iodine Containing Contrast Media (ICCM). This may result in displacement of materials, compromising technical success. In this study we compare the stickiness of seven frequently used types of ICCM.

MATERIAL AND METHODS

Xenetix 300, Hexabrix 320 (Guerbet, Villepinte, France), Ultravist 300 (Bayer, Leverkusen, Germany), Visipaque 270, Omnipaque 300, Visipaque 320 (GE, Wauwatosa, WI) and Iomeron300 (Bracco, Milano, Italy) are compared using a probe-tack test. Pieces of surgical gloves are put together with 0.1 ml of of ICCM in between, and subsequently pulled apart under computer control. Stickiness is measured as the work needed to separate the probes.

RESULTS

From least to most sticky results were: Hexabrix 320 (mean Work (mJ); range: 0.70; 0.16-1.23), Visipaque 270 (1.18; 0.47-1.89), Visipaque 320 (1.70; 0.59-2.81), Iomeron 300 (3.01; 1.82-4.20), Xenetix 300 (5.83; 3.96-7.69), Ultravist 300 (5.83; 2.83-8.84), Omnipaque 300 (8.14; 6.95-9.33). The four least sticky ICCM differ statistically significantly (p = 0.000-0.004) from the remaining. In this research Omnipaque 300, Ultravist 300 and Xenetix 300 are the stickiest and may hence pose the greatest practical problems during procedures; in contrast, Hexabrix 320, Visipaque 270 and Visipaque 320 are the least sticky in this research and may therefore aid in constraining complications caused by stickiness.

CONCLUSION

A significant and reproducible difference in stickiness exists between commercially available ICCM, Hexabrix 320, Visipaque 270, Visipaque 320 and Iomeron 300, being least sticky.

Additional use of extrinsic warmer for intravenous CT contrast media and its impact on incidence of contrast extravasations and allergic like reactions: a prospective observational case control study

AIMS

To prospectively determine whether extrinsic warming of the low-osmolality CT contrast media (Iohexol 350, Iodixanol 320, Iopromide 300, and Iopamidol 300) to 37°C prior to intravenous administration affects extravasation and allergic-like reaction rates.

MATERIALS AND METHODS

This large scale prospective case control study of adverse events included all the patients between the age group of 15-80 years undergoing routine contrast-enhanced computed tomographic (CECT) examinations from April 2018 to March 2020 at our institute. Ex vivo experiments were also performed to demonstrate change in contrast viscosity and fluid dynamics in relation to temperature.

RESULTS

A total of 24,379 CECTs were conducted during the study period. Extrinsic warming showed a significant decrease in extravasation rates for Iohexol 350 at flow rates <3.5 mL/sec (P=0.037). No significant difference was observed with Iopromide 300 (P=0.432). Overall, a significant decrease in allergic reactions and overall contrast-related reactions (excluding physiologic reactions) was noted (P<0.001), with Iohexol 350. However, no significant difference was found with Iopromide 300. The most common physiological reaction was a sense of warmth, more prevalent in the warmed group, aligning with ex-vivo experiments demonstrating decreased viscosity with contrast warming.

CONCLUSIONS

Extrinsic warming of contrast helps reduce the incidence of allergic-like reactions and extravasations for Iohexol 350, but no significant difference was noted with Iopromide 300 even at low injection rates (<3.5 mL/sec).

The relationship between iodinated contrast material temperature and adverse reactions: A meta-analysis of 307,329 injections

OBJECTIVE

The effect of iodinated contrast material (CM) temperature on injection pressures and viscosity has been well established. However, the effect of extrinsic warming of CM on allergic reactions and extravasations remains unclear. The purpose of this study is to compare the rates of allergic reactions and extravasations between warmed CM to room temperature CM.

METHODS

We conducted a comprehensive systematic search using PubMed, Embase, and Web of Science databases for all studies that assess the impact of warmed CM on adverse reactions. The primary outcomes of our study were allergic reaction and extravasation rates. We calculated weighted pooled odds ratios (OR) and 95% confidence intervals (CI) for all outcomes using the random-effects model. A P-value <0.05 was considered statistically significant. We conducted subgroup analyses based on the viscosity of the CM.

RESULTS

A total of five studies, including 307,329 CM injections (86,676 at room temperature and 220,653 warmed to 37 °C), were included in the analysis. For high viscosity CM, pre-warming was associated with significantly lower allergic reaction rates (OR: 0.59, 95% CI: 0.49-0.72, P < 0.00001). There was no significant difference in rates of extravasation for high viscosity CM (OR: 0.53, 95% CI: 0.20-1.43, P = 0.21).

DISCUSSION

Our meta-analysis suggests that warming CM to 37 °C is a safe and effective approach to reduce the risk of allergic reactions and physiologic reactions during injection of high-viscosity CM. However, there was no significant difference in extravasation rates between warmed and room temperature CM, regardless of viscosity.

Warmed contrast media temperature loss in traditional manifold systems during angiographic procedures

BACKGROUND

Extrinsic warming of contrast media (CM) to 37 °C before angiographic procedures is performed to improve bolus kinetics and avoid potential adverse effects. Extrinsically warmed CM readily loses temperature after removal from the warming cabinet, but the extent of its cooling has not been previously investigated.

PURPOSE

To assess temperature loss of extrinsically warmed CM in tubing of traditional angiographic manifolds during simulated angiography.

MATERIAL AND METHODS

In total, 35 scheduled diagnostic angiographic procedures were observed in a hospital setting. Relevant time points of CM use during the procedures were recorded. The shortest, median, and longest procedures were then simulated in the experimental laboratory to measure CM temperatures at specific times at three locations along the tubing system.

RESULTS

The angiographic procedures lasted 7.0-26.6 min (median = 11.7 min), with the total duration dependent primarily on the time from contrast being removed from the warming cabinet to the commencement of imaging. During the simulated procedures, consistent patterns of temperature loss were observed. By the last simulated angiographic run, injected CM temperature decreased by 7.4-16.4 °C, depending on procedure length. Most of the heat loss occurred in the tubing between the CM bottle and coronary control syringe.

CONCLUSION

During angiographic procedures, prewarmed CM loses its temperature rapidly with the duration of exposure to ambient room temperature. If no additional measures are employed to maintain its temperature outside of the warming cabinet, extrinsic warming has limited impact on injected CM temperature.

Effect of Extrinsic Warming of Low-Osmolality CT Contrast Media (Iohexol 350) on Extravasations and Patient Reaction Rates: A Retrospective Study

Background: Extrinsic warming of iodinated CT contrast media to body temperature reduces viscosity and injection pressures. However, studies examining the effect of extrinsic warming on clinical adverse events are limited in number and provide conflicting results. Therefore, consensus practice recommendations have been sparse. Objective: To compare rates of extravasation, allergic/allergic-like reactions, and physiologic reactions between iohexol 350 warmed to body temperature (37°C) and maintained at room temperature. Methods: This retrospective study compared adult patients who received CT examinations using IV iohexol 350 that had either been warmed to body temperature or maintained at room temperature. At our institution, contrast media had historically been warmed to body temperature prior to a protocol change unrelated to this investigation. Patient and CT examination characteristics were extracted from the electronic medical record. Adverse events, including extravasations, allergic/allergic-like reactions, and physiologic reactions, were compared between groups. Results: A total of 3939 patients received contrast media warmed to body temperature before the protocol change; 3933 patients received contrast media at room temperature after the protocol change. The body temperature group experienced 11 (0.28%; 95% CI 0.14%, 0.50%) adverse events, all extravasations; allergic/allergic-reaction rate was 0.00% (97.5% CI 0.00%, 0.09%). The room temperature group experienced 17 (0.43%; 95% CI 0.25%, 0.69%) adverse events [13 (0.33%; 95% CI 0.17%, 0.56%) extravasations; 4 (0.10%; 95% CI 0.03%, 0.26%) allergic/allergic-like reactions]. No physiologic reaction occurred in either group. The two groups were not different in terms of overall reaction rate (p=.19), extravasation rate (p=.69), allergic/allergic-like reaction rate (p=.06), or physiologic reaction rate (p>.99). Logistic regression adjusting for patient and CT characteristics (age, sex, conventional CT vs CTA, contrast media volume, injection location, needle gauge) showed no significant association of patient group and adverse reaction rate (odds ratio=2.19, 95% CI 0.68-7.00). Multivariable regression modeling demonstrated an excess of 0.27 adverse events per 100 patients within the room temperature group, below a 0.6% non-inferiority margin. Conclusion: The data suggest that maintaining iohexol 350 at room temperature is non-inferior to warming the agent to body temperature before injection. Clinical Impact: The resources involved to prewarm iohexol 350 before injection may not be warranted.

Contrast agents in diagnostic imaging: Present and future

Specific contrast agents have been developed for x ray examinations (mainly CT), sonography and Magnetic Resonance Imaging. Most of them are extracellular agents which create different enhancement on basis of different vascularization or on basis of different interstitial network in tissues, but some can be targeted to a particular cell line (e.g. hepatocyte). Microbubbles can be used as carrier for therapeutic drugs which can be released in specific targets under sonographic guidance, decreasing systemic toxicity and increasing therapeutic effect. Radiologists have to choose a particular contrast agent knowing its physical and chemical properties and the possibility of adverse reactions and balancing them with the clinical benefits of a more accurate diagnosis. As for any drug, contrast agents can cause adverse events, which are more frequent with Iodine based CA, but also with Gd based CA and even with sonographic contrast agents hypersensitivity reaction can occur.

In Vivo Imaging of Intraocular Fluidics in Vitrectomized Swine Eyes Using a Digital Fluoroscopy System

Purpose. To describe the characteristics of intraocular fluidics during cataract surgery in swine eyes with prior vitrectomy. Methods. We prepared three groups of enucleated swine eyes (nonvitrectomized, core, and totally vitrectomized). Irrigation and aspiration were performed (2.7 mm conventional sleeved phacosystem) using a balanced saline solution mixed with a water-soluble radiopaque contrast medium at 1 : 1 ratio. We imaged the eyes using a digital fluoroscopy system (DFS) during phacoemulsification and compared the characteristics of the intraocular fluid dynamics between the groups. Results. The anterior chamber depth (ACD) after the commencement of irrigation differed between groups (2.25 ± 0.06 mm; 2.33 ± 0.06 mm; 3.17 ± 0.11 mm), as well as the height of the fluid flowing from the anterior chamber into the posterior cavity that was identified by lifting up the iris to correct the infusion deviation syndrome (0.00 ± 0.00 mm; 0.41 ± 0.04 mm; 2.19 ± 0.35 mm). Conclusions. DFS demonstrated differences in fluid dynamics during phacoemulsification in swine eyes with or without prior vitrectomy. In completely vitrectomized eyes, the large ACD, which developed during phacoemulsification, could be reduced by lifting the iris and allowing the fluid to shift to the posterior cavity. Recognizing the differences in fluidics of vitrectomized eyes as compared to those of the nonvitrectomized eyes may reduce the frequency of intraoperative complications.

Pressure injectors for radiologists: A review and what is new

Pressure Injectors are used routinely in diagnostic and interventional radiology. Advances in medical science and technology have made it is imperative for both diagnostic as well as interventional radiologists to have a thorough understanding of the various aspects of pressure injectors. Further, as many radiologists may not be fully conversant with injections into ports, central lines and PICCs, it is important to familiarize oneself with the same. It is also important to follow stringent operating protocols during the use of pressure injectors to prevent complications such as contrast extravastion, sepsis and air embolism. This article aims to update existing knowledge base in this respect.

Impact of contrast agent viscosity on coronary balloon deflation times: bench testing results

OBJECTIVES

To assess the impact of viscosity on angioplasty balloon deflation times.

BACKGROUND

Lower contrast viscosity could result in more rapid coronary balloon deflation times.

METHODS

We performed a bench comparison of coronary balloon deflation times using 2 contrast agents with different viscosity (ioxaglate and iodixanol), 3 contrast dilutions, and 2 inflation syringe filling volumes. Ten identical pairs of coronary angioplasty balloons were used to conduct each comparison after balloon inflation to 12 atmospheres. Simultaneous deflations were performed under cineangiography. The time to full contrast extraction and the area of contrast remaining after 5 seconds of deflation (quantified by opaque pixel count) were compared between groups.

RESULTS

The mean time to full contrast extraction during balloon deflation was 8.3 ± 2.5 seconds for ioxaglate (lower viscosity) versus 10.1 ± 2.9 seconds for iodixanol (higher viscosity) (17.4% decrease, P = 0.005), with a 35.6% (P = 0.004) reduction in contrast area at 5 seconds. Compared to 1:1 ioxaglate-saline mixture, 1:2 and 1:3 ioxaglate/saline mixes resulted in 26.7% (P < 0.001) and 39.0% (P < 0.001) reduction in mean balloon deflation time, respectively, but at the expense of decreased balloon opacity. Filling the inflation syringe with 5 versus 15 ml of contrast/saline solution was associated with 7.5% decrease in balloon deflation time (P = 0.005), but no difference in contrast area at 5 seconds (P = 0.749).

CONCLUSIONS

Use of a lower viscosity contrast agent and higher contrast dilution significantly reduced coronary balloon deflation times, whereas use of lower syringe filling volume had a modest effect. Rapid coronary balloon deflation could improve the safety of interventional procedures.

Rate of contrast material extravasations and allergic-like reactions: effect of extrinsic warming of low-osmolality iodinated CT contrast material to 37 degrees C

PURPOSE

To retrospectively determine whether extrinsic warming of the low-osmolality contrast material iopamidol to 37°C prior to intravenous administration at computed tomography (CT) affects extravasation and allergic-like reaction rates.

MATERIALS AND METHODS

The need to obtain informed patient consent was waived for this HIPAA-compliant and institutional review board-approved analysis. All adverse events related to the intravenous administration of iopamidol during CT examinations occurring 200 days before (period 1) and 200 days after (period 2) the cessation of extrinsic contrast material warming (37°C) for intravenous injections of less than 6 mL/sec at Duke University Medical Center (Durham, NC) were retrospectively reviewed. Adverse event rates were compared by using χ2 statistics.

RESULTS

There were 12,682 injections during period 1 (10,831 injections of iopamidol 300 and 1851 injections of iopamidol 370) and 12,138 injections (10, 064 injections of iopamidol 300 and 2074 injections of iopamidol 370) during period 2. Adverse event rates for iopamidol 300 were not affected by extrinsic warming (extravasation rates: 0.30% [32 of 10,831] in period 1 vs 0.23% [23 of 10,064] in period 2, P=.64; allergic-like reaction rates: 0.39% [42 of 10,831] in period 1 vs 0.46% [46 of 10,064] in period 2, P=.74; overall adverse events: 0.68% [74 of 10,831] in period 1 vs 0.69% [69 of 10,064] in period 2, P=.99). Discontinuation of extrinsic warming was associated with significantly increased extravasation and overall adverse event rates for iopamidol 370 (extravasation rates: 0.27% [five of 1851] vs 0.87% [18 of 2074], P=.05; allergic-like reaction rates: 0.16% [three of 1851] vs 0.39% [eight of 2074], P=.42; overall adverse events: 0.43% [eight of 1851] vs 1.25% [26 of 2074], P=.02).

CONCLUSION

Extrinsic warming (to 37°C) does not appear to affect adverse event rates for intravenous injections of iopamidol 300 of less than 6 mL/sec but is associated with a significant reduction in extravasation and overall adverse event rates for the more viscous iopamidol 370.

Intravenous contrast medium administration and scan timing at CT: considerations and approaches

The continuing advances in computed tomographic (CT) technology in the past decades have provided ongoing opportunities to improve CT image quality and clinical practice and discover new clinical CT imaging applications. New CT technology, however, has introduced new challenges in clinical radiology practice. One of the challenges is with intravenous contrast medium administration and scan timing. In this article, contrast medium pharmacokinetics and patient, contrast medium, and CT scanning factors associated with contrast enhancement and scan timing are presented and discussed. Published data from clinical studies of contrast medium and physiology are reviewed and interpreted. Computer simulation data are analyzed to provide an in-depth analysis of various factors associated with contrast enhancement and scan timing. On the basis of basic principles and analysis of the factors, clinical considerations and modifications to protocol design that are necessary to optimize contrast enhancement for common clinical CT applications are proposed.