Evaluation of the Performance of Glomerular Filtration Rate Measurement Using CT Urography in Patients With a GFR Below 60 mL/Min/1.73 m²

NCT07042698 | Not Yet Recruiting

• 1 other identifier: APHP250438
• Study Type: interventional
• Target: 70
• Locations: 1 country
• Sites: 1

Brief Summary

Glomerular filtration rate (GFR), which is the main biomarker used in clinical practice to assess kidney function, is usually estimated from the serum concentration of endogenous markers such as creatinine and/or cystatin C. GFR estimation equations all share the disadvantage of imperfect accuracy due to non-GFR-related determinants of creatinine and cystatin C. When knowing the exact GFR value is necessary for clinical decision-making, measurement by clearance of an exogenous tracer is required. Various tracers are available, some of which are radioactive tracers (99mTc-DTPA and 51Cr-EDTA), while others are iodinated contrast agents (iohexol, iothalamate). GFR measurement procedures are time-consuming and require significant human resources (4 to 5 hours, or even 24 hours for plasma clearances at very low GFR values).Urinary clearance methods may be inaccurate in cases of inadequate voiding. Plasma clearance results may be inaccurate in cases of increased (overestimation) or decreased (underestimation) extracellular volume, low GFR (unless late sampling is performed), or glomerular hyperfiltration. Measuring tracers requires either warm labs for measuring radioactive markers or labs with HPLC (High Performance Liquid Chromatography) chains for iohexol, which are part of an external quality assurance program. The complexity and/or length of GFR measurement procedures, their cost, and laboratory constraints explain why measured GFR is underused in routine clinical practice. There is a critical need to develop GFR measurement methods that are simpler to implement, reliable across the entire GFR spectrum, and widely available. We have demonstrated that it is possible to measure GFR using 4-phase CT urography performed as part of the care of living kidney donor candidates (healthy individuals with normal GFR). The examination takes 10 minutes, requires no biological sampling, and is not subject to potential inaccuracies due to sodium overload or poor bladder emptying.

Conditions

Kidney Diseases; Tomography; X-Ray Computed

Keywords

Glomerular Filtration Rate; Tomography; X-Ray Computed

Outcome Measures

Primary Outcomes (1)

• Assessment of the Reliability of GFR Measurement by 4-Phase CT Urography Compared to Iohexol Clearance

  To assess whether GFR measurement using 4-phase CT urography is reliable in patients with GFR below 60 ml/min/1.73 m², as compared with iohexol clearance (reference method): - Unbiased (mean difference between CT-measured GFR and iohexol clearance not different from zero). - and accurate: at least 50% and 80% of GFR values measured by CT urography within 10% and 20% of biological clearance values for iohexol clearance.

  Day 1

Secondary Outcomes (3)

• Reliability Assessment of GFR Estimation Using Creatinine and/or Cystatin C Compared to Iohexol Clearance

  Day 1

• Reliability of Hybrid GFR (Mean of CT-Measured and Creatinine/Cystatin C Estimated GFR)

  Day 1

• Reliability of CT-Measured GFR Across Patient Subgroups Defined by Estimated GFR Ranges

  Day 1

Study Arms (1)

GFR Measurement Using 4-Phase CT Urography and Comparison with Iohexol Clearance

OTHER

A study with one arm, adding experimental procedures to standard of care (a 4-phase CT urography and biological sampling) in order to evaluate the accuracy of GFR measurement by CT urography in patients with chronic kidney disease.

Other: Glomerular Filtration Rate measurement with iohexol clearance

Interventions

Glomerular Filtration Rate measurement with iohexol clearance OTHER

After performing a 4-phase CT urography (or 3-phase CT scan, with the addition of a 4th phase for research purposes), performed for clinical indications as part of the patient's care, and using iohexol as a contrast agent, patients will undergo a biological measurement of iohexol clearance, based on serum and urine samples taken over 4 periods of 1 hour, between 3 and 7 hours after the CT scan. No iohexol will be reinjected to measure GFR. The CT scan images will be segmented by the investigator to determine the CT-measured GFR.

GFR Measurement Using 4-Phase CT Urography and Comparison with Iohexol Clearance

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Patients older than 18 years of age
• Having given written consent to participate in the study
• Patient referred to the medical imaging department of the Henri Mondor University Hospital for a 3-phase or 4-phase abdominal CT scan
• With an estimated GFR according to CKD-EPIcreat2009 \< 60 ml/min/1.73m²
• Hospitalized or outpatient
• Affiliated with French national health insurance

You may not qualify if:

• Patients with hip implants, due to artifacts that make quantification of the contrast agent in the bladder unreliable
• Lack of health insurance
• Patients under legal protection.

Sponsors & Collaborators

• Assistance Publique - Hôpitaux de Paris: lead

Study Sites (1)

Assistance Publique Hôpitaux de Paris - CHU Henri Mondor - Créteil

Créteil, Île-de-France Region, 94000, France

Location

MeSH Terms

Conditions

Kidney Diseases

Condition Hierarchy (Ancestors)

Urologic Diseases; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Male Urogenital Diseases

Central Study Contacts

Thomas STEHLE, Dr

CONTACT

+33145178452; thomas.stehle@aphp.fr

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: DIAGNOSTIC
• Intervention Model: SINGLE GROUP
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: June 17, 2025
• First Posted: June 29, 2025
• Study Start: July 15, 2025
• Primary Completion (Estimated): July 14, 2027
• Study Completion (Estimated): July 15, 2027
• Last Updated: June 29, 2025

Record last verified: 2025-06

Data Sharing

• IPD Sharing: Will not share

Locations

FR (1)