An interventional study of biological samples collection in Magnetic Resonance Imaging, sponsored by Centre Hospitalier Régional Metz-Thionville. Recruiting at 2 sites in France. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-08-21.
Sponsored by Centre Hospitalier Régional Metz-Thionville · Not applicable, Interventional, and Other
This is a single-center cohort study aimed to describe the urinary excretion kinetics of gadolinium contrast agents (Gd-CAs). Patients with a prescription for injected MRI are invited to participate in the study. If they agree, blood and urine samples are collected before Gd-CAs injection, and urine samples are collected between 0- and two-and-a-half-hours post-injection of Gd-CAs.
The contrast agents used in MRI to characterize certain lesions contain a chemical element from the rare earth family: Gadolinium (Gd). Gd, in its isolated form, is toxic in humans, but it can still be used in the form of complex molecules such as gadolinium contrast agents (Gd-CAs), which retain its contrast power while greatly minimizing its toxicity.
The MRI is performed rapidly after the injection of Gd-CAs, and these compounds are eliminated by the urinary route in the first urine following the examination. After elimination, and in view of their very high stability, these compounds follow the path of wastewater via sewage treatment plants. However, the processes currently used in these plants do not retain them, and they remain present in the purified water discharged into rivers.
Work carried out at the Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC) at the University of Lorraine has demonstrated the bioaccumulation of these compounds in freshwater organisms. Gd-CAs then follow the classic pathway of continental waters. It should be noted that the quantity of Gd released as a result of MRI activities has been estimated on average at 1 injection per 1 g of Gd used.
In order to prevent future environmental disorders, recovery of all or part of the Gd-CAs immediately after MRI by urine collection is undoubtedly the most effective approach.
The aim of this project is to assess the feasibility of such an approach, and to propose a protocol applicable to MRI involving the injection of gadolinium contrast agents for urine collection.
This project is part of the "Rare Earths" theme of LabEx R21. It will examine the possibility of recycling gadolinium as an element or as Gd-CAs.
Centre Hospitalier Régional Metz-Thionville is the lead sponsor of 123 studies on the registry; 21 are open to participants now.
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Patients:
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
urine samples are collected before Gd-CAs injection, and between 0- and two-and-a-half-hour post-injection of Gd-CAs.
Other: biological samples collection
Urine samples are collected before Gd-CAs injection, and between 0- and two-and-a-half-hour post-injection of Gd-CAs.
Urinary excretion of gadolinium-based contrast agents (Gd-CAs)
Describe the kinetics of urinary excretion of GdCAs during the 2H30 following gadoline contrast injection in patients undergoing injected MRI at the Mercy Hospital Medical Imaging Department. The cumulative quantity of gadolinium-based contrast agents (Gd-CAs) (mg) mesured in urine during spontaneous micturition between 0 and 2H30 after injection of gadoline contrast medium and during micturition on demand at 2.30 h. The amount of Gd present in the urine (directly associated with the presence of Gd-CAs) is determined by inductively coupled plasma mass spectrometry (ICPMS). Urine concentrations are expressed in µg/L. Taking into account the volume of urine collected, the quantity of Gd is calculated and expressed in mg. This quantity is then expressed as a percentage of the quantity of injected-Gd-CAs.
Time frame: at 2 hours and a half after Gd-CAs injection
Renal function
Glomerular filtration rate (GFR: mL/min) estimated by the CKD-EPI method on the day of MRI.
Time frame: Day 0 (MRI)
Volume of beverages
Volume of beverages drunk (mL) after each micturition, declared by the patient since Gd-CAs injection, to the nearest 100 mL.
Time frame: at 2 hours and a half after Gd-CAs injection
Time to first spontaneous micturition
Duration (in minutes) between time of Gd-CAs injection and time of first spontaneous micturition.
Time frame: up to 2 hours and a half after Gd-CAs injection
Study refusal rate
Percentage (%) of study refusal
Time frame: Day 0 (MRI)
Rate of premature study exit
Percentage (%) of premature study exit
Time frame: at 2 hours and a half after Gd-CAs injection
Plan to share: No
No publications or documents are linked to this record.
Started Apr 2024 (actual). Primary completion is estimated for Apr 2028, 48 months after the start.
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