Waiting times between examinations with intravascularly administered contrast media: a review of contrast media pharmacokinetics and updated ESUR Contrast Media Safety Committee guidelines

ESR Essentials: gadolinium-wise MRI-practice recommendations by the European Society for Magnetic Resonance in Medicine and Biology

The Gadolinium Research and Education Committee (GREC) is a working group of the European Society for Magnetic Resonance in Medicine and Biology (ESMRMB), established in 2016. The aim of the committee is to monitor scientific evidence for a continuous quality and safety improvement of enhanced MRI using gadolinium-based contrast agents (GBCAs), and also assess potential alternatives. The scope of the present article is to describe the level of evidence concerning safety beyond the single patient (access to community and environmental impact), justification and optimization of the use of GBCAs beyond dosage (appropriateness and influence on clinical decision making), dose reduction with the use of AI (benefits and pitfalls), the advent of next-generation GBCAs (based on currently available data). CLINICAL RELEVANCE: GBCAs are extensively used in MRI and influence clinical decision-making. Their use to enhance the contrast-to-noise ratio is guided by recommendations from subspecialty societies. These guidelines advocate for GBCA use as an additional tool when necessary, ensuring they are administered at the lowest reasonable dose. KEY POINTS: The choice of GBCAs used in radiology should be based on MRI cost-effectiveness, MRI access to the patient community, and impact on the environment, (evidence level: low). GBCA optimization includes reducing GBCA volume burden and increasing appropriateness by including post-contrast enhancement in MRI protocols, depending on clinical indications, (evidence level: moderate). Next-generation GBCAs show higher kinetic stability and higher T1 relaxivity when compared with standard macrocyclic GBCAs allowing comparable diagnostic accuracy at lower doses, (evidence level: moderate).

Foix-Alajouanine syndrome: a comprehensive overview of rare but relevant diagnosis

Introduction

Foix-Alajouanine syndrome (FAS) is an uncommon neurological disorder marked by the gradual development of spinal cord congestion. First documented by Foix and Alajouanine in 1926. Although it is infrequent, delayed or misdiagnosis is nonetheless prevalent, resulting in inadequate therapy and unfavorable results.

Methods

Using the PubMed database, MEDLINE, and EMBASE, we collected data on FAS patients and conducted a pooled analysis. The term 'FAS' was used to search for related articles. Our search was restricted to previous clinical case reports or series that were published in English. Non-English articles were excluded. We included the articles in the period from 1974 to 2024. Articles were eligible if the radiographic and clinical findings were indicative of FAS. A thorough research analysis was performed, examining case reports that specifically addressed this issue. This study examines the clinical symptoms, difficulties in diagnosis, methods of treatment, and outcomes related to FAS.

Results

FAS predominantly impacts the elderly population. A total of 26 patients were diagnosed with FAS. The median age of affected individuals was 53 (SD ±15.96). The ratio of males to females is roughly 5:1. The clinical manifestations encompass gradual muscle weakness and sensory impairments. The diagnosis is dependent on radiological evaluations, specifically MRI and digital subtraction angiography. Possible treatments include endovascular therapy, surgical closure of arteriovenous fistula, or a combination of the two. Significant improvements in neurological impairments can be achieved by early intervention.

Conclusion

The diagnosis of FAS continues to be difficult due to its infrequency and varied clinical manifestations. Prompt and precise diagnosis is essential for proper intervention, typically utilizing endovascular or surgical methods. Additional research is required to determine prognostic markers and enhance long-term care techniques for this rare neurological condition.

The GREENWATER study: patients' green sensitivity and potential recovery of injected contrast agents

OBJECTIVES

The environmental footprint of iodinated contrast agents (ICAs) and gadolinium-based contrast agents (GBCAs) is noteworthy. This study assesses: (1) patients' "green sensitivity" as measured by their acceptance in a sustainability study and (2) the resulting potential reduction of contrast residuals in wastewater.

MATERIALS AND METHODS

After ethical approval, participants scheduled for administration of ICAs or GBCAs for diagnostic purposes were enrolled in this prospective observational study from July 2022 to October 2023. They were asked to prolong their hospital stay by up to 60 min to collect their first urine in dedicated canisters, thereby measuring the recovery rates of ICAs and GBCAs as found/theoretical ratio of concentrations. Mann-Whitney U, χ2 tests, and multivariable regression analysis were used.

RESULTS

Patients scheduled for contrast-enhanced CT or MRI (n = 455) were screened; 422 (92.7%) accepted to participate. We enrolled 212 patients administered with ICAs and 210 administered with GBCAs. The median recovery rate was 51.2% (interquartile range 29.2-77.9%) for ICAs and 12.9% (9.0-19.3%) for GBCAs. At multivariable analysis, a significant effect of patient age (ICAs, p = 0.001; GBCAs, p = 0.014), urine volume (p < 0.001 for both), and time interval from contrast administration to urine collection (p < 0.001 for both) on recovery rates was found for both contrast agents; injected contrast volume (p = 0.046) and saline flushing usage (p = 0.008) showed a significant effect only for ICAs.

CONCLUSION

The high patient enrollment compliance (93%) and potential recovery rates of 51% (ICAs) and 13% (GBCAs) play in favor of sustainable practices in reducing the environmental footprint of contrast agents.

KEY POINTS

Question How many patients are willing to extend their stay in radiology by up to 60 min to help reduce the environmental impact of contrast agents? Findings Over 90% of screened patients agreed to extend their stay by up to 60 min and collect their urine in dedicated containers. Clinical relevance Patients demonstrated a high willingness to cooperate in reducing the environmental impact of contrast agents, allowing for a potential recovery of approximately 51% for iodinated and 13% for gadolinium-based contrast agents.

Anthropogenic gadolinium contaminations in the marine environment and its ecological implications

Due to the widespread application in medicine and industry of anthropogenic gadolinium (Gdanth), the widespread of Gd anomaly in surface water has leading to disruption of the natural Gd geochemical cycle. However, challenges related to the identification and quantification of Gdanth, assessment of its impacts on marine ecosystems, and exploration of strategies for mitigating its adverse effects still exist. Meanwhile, as the major source of the Gdanth, the environmental geochemical behavior of Gd-based contrast agents (GBCAs), which are used in medical diagnostics in magnetic resonance imaging (MRI), are still poorly understood. In this review, we 1) analyzed Gd anomalies in samples from published literature worldwide, confirmed their prevalence (81.25% for sea and lake water, 72.73% for river water), 2) demonstrated that the third-order polynomial method is the preferred approach for the detection of Gdanth in surface seawater, 3) outlined the species and applications of Gdanth and its impacts on marine environment, 4) explored the process of GBCAs influx into the ocean and demonstrated the concentration of Gdanth in coral samples was mainly affected by terrestrial input GBCAs (63.75%) through Pearson correlation analysis and principle component analysis, 5) proposed effective management strategies for GBCAs at all stages from production to release into the ocean, 6) formulated an expectation for future research on marine Gdanth.

Nephroprotection and iodinate contrast medias

The incidence of post-contrast acute kidney injury (PC-AKI) is low with the new low- or iso-osmolar non-ionic iodinated contrast agents. The only proven form of prophylaxis for PC-AKI is hydration, preferably intravenous, although oral hydration is equally effective. In this article we define PC-AKI and its risk factors, propose a prophylaxis protocol and respond to the most common doubts that arise around prophylaxis. We also update the fasting guidelines to be followed prior to contrast testing. In general, fasting of solids is not necessary before injecting iodinated contrast or gadolinium except in tests in which it is necessary to specifically study the upper digestive tract and bile duct. Even in these cases, fasting clear liquids is not required, which is of great help for oral hydration and for reducing the incidence of PC-AKI.

Analytical interference of intravascular contrast agents with clinical laboratory tests: a joint guideline by the ESUR Contrast Media Safety Committee and the Preanalytical Phase Working Group of the EFLM Science Committee

The Contrast Media Safety Committee of the European Society of Urogenital Radiology has, together with the Preanalytical Phase Working Group of the EFLM Science Committee, reviewed the literature and updated its recommendations to increase awareness and provide insight into these interferences. CLINICAL RELEVANCE STATEMENT: Contrast Media may interfere with clinical laboratory tests. Awareness of potential interference may prevent unwanted misdiagnosis. KEY POINTS: • Contrast Media may interfere with clinical laboratory tests; therefore awareness of potential interference may prevent unwanted misdiagnosis. • Clinical Laboratory tests should be performed prior to radiological imaging with contrast media or alternatively, blood or urine collection should be delayed, depending on kidney function.

An Algorithm for Waiting Times between Imaging Studies with Contrast Media and Prevention of Interference in Clinical Laboratory Tests

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Analytical interference of intravascular contrast agents with clinical laboratory tests: a joint guideline by the ESUR Contrast Media Safety Committee and the Preanalytical Phase Working Group of the EFLM Science Committee

The Contrast Media Safety Committee of the European Society of Urogenital Radiology has, together with the Preanalytical Phase Working Group of the EFLM Science Committee, reviewed the literature and updated its recommendations to increase awareness and provide insight into these interferences.

Just give the contrast? Appraisal of guidelines on intravenous iodinated contrast media use in patients with kidney disease

OBJECTIVE

To appraise the quality of guidelines on intravenous iodinated contrast media (ICM) use in patients with kidney disease, and to compare the recommendations among them.

METHODS

We searched four literature databases, eight guideline libraries, and ten homepages of radiological societies to identify English and Chinese guidelines on intravenous ICM use in patients with kidney disease published between January 2018 and June 2023. The quality of the guidelines was assessed with the Scientific, Transparent, and Applicable Rankings (STAR) tool.

RESULTS

Ten guidelines were included, with a median STAR score of 46.0 (range 28.5-61.5). The guidelines performed well in "Recommendations" domain (31/40, 78%), while poor in "Registry" (0/20, 0%) and "Protocol" domains (0/20, 0%). Nine guidelines recommended estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73 m2 as the cutoff for referring patients to discuss the risk-benefit balance of ICM administration. Three guidelines further suggested that patients with an eGFR < 45 mL/min/1.73 m2 and high-risk factors also need referring. Variable recommendations were seen in the acceptable time interval between renal function test and ICM administration, and that between scan and repeated scan. Nine guidelines recommended to use iso-osmolar or low-osmolar ICM, while no consensus has been reached for the dosing of ICM. Nine guidelines supported hydration after ICM use, but their protocols varied. Drugs or blood purification therapy were not recommended as preventative means.

CONCLUSION

Guidelines on intravenous ICM use in patients with kidney disease have heterogeneous quality. The scientific societies may consider joint statements on controversial recommendations for variable timing and protocols.

CRITICAL RELEVANCE STATEMENT

The heterogeneous quality of guidelines, and their controversial recommendations, leave gaps in workflow timing, dosing, and post-administration hydration protocols of contrast-enhanced CT scans for patients with kidney diseases, calling for more evidence to establish a safer and more practicable workflow.

KEY POINTS

• Guidelines concerning iodinated contrast media use in kidney disease patients vary. • Controversy remains in workflow timing, contrast dosing, and post-administration hydration protocols. • Investigations are encouraged to establish a safer iodinated contrast media use workflow.

Ten years of gadolinium retention and deposition: ESMRMB-GREC looks backward and forward

In 2014, for the first time, visible hyperintensities on unenhanced T1-weighted images in the nucleus dentatus and globus pallidus of the brain were associated with previous Gadolinium-based contrast agent (GBCA) injections and gadolinium deposition in patients with normal renal function. This led to a frenzy of retrospective studies with varying methodologies that the European Society of Magnetic Resonance in Medicine and Biology Gadolinium Research and Educational Committee (ESMRMB-GREC) summarised in 2019. Now, after 10 years, the members of the ESMRMB-GREC look backward and forward and review the current state of knowledge of gadolinium retention and deposition. CLINICAL RELEVANCE STATEMENT: Gadolinium deposition is associated with the use of linear GBCA but no clinical symptoms have been associated with gadolinium deposition. KEY POINTS : • Traces of Gadolinium-based contrast agent-derived gadolinium can be retained in multiple organs for a prolonged time. • Gadolinium deposition is associated with the use of linear Gadolinium-based contrast agents. • No clinical symptoms have been associated with gadolinium deposition.