Contrast Volume as a Predictor of Kidney Injury Following Contrast-Enhanced CT

Prospective Evaluation of Contrast Volume as a Predictor of Contrast-Associated Acute Kidney Injury Following Intravenous Contrast-Enhanced Computed Tomography

Iodinated contrast dye used during computed tomography (CT) scans can sometimes cause kidney stress or damage, known as contrast-associated acute kidney injury (CA-AKI). Currently, doctors evaluate a patient's kidney safety using standard estimated glomerular filtration rate (eGFR). However, standard eGFR is calculated for an average body size rather than an individual's actual body size, which can misrepresent a person's true kidney excretion capacity. This study aims to evaluate whether comparing the volume of contrast dye directly to a patient's true, individualized kidney function (the contrast volume-to-absolute GFR ratio) can accurately predict the risk of developing kidney injury after an intravenous contrast-enhanced CT scan.

This is a prospective, observational study involving adult outpatients who are already scheduled for a clinically necessary contrast-enhanced CT scan. Participation is observational and does not alter the patient's planned scan, medical treatment, or the amount of contrast dye administered by their healthcare team.

Participants will:

• Have their baseline kidney function assessed through a routine blood test (serum creatinine) within 48 hours prior to their CT scan.
• Have their height and weight recorded to calculate their individualized, absolute kidney function.
• Complete a follow-up blood test (serum creatinine) 48 to 72 hours after the CT scan to evaluate any changes in kidney function.

Researchers will analyze whether the ratio of contrast volume to absolute kidney function reliably identifies patients at higher risk of contrast-associated kidney complications, helping to establish safer, personalized contrast dosing strategies in the future.

Inclusion Criteria:

• Adult patients aged 18 years or older referred for clinically indicated outpatient intravenous contrast-enhanced computed tomography (CE-CT) scan.
• Documented baseline serum creatinine and estimated glomerular filtration rate (eGFR) measured within 48 hours prior to contrast exposure.
• Provision of written informed consent prior to study enrollment.

Exclusion Criteria:

• Severe chronic kidney disease (CKD stage 5, baseline eGFR < 15 mL/min/1.73 m2) or currently on chronic renal replacement therapy (hemodialysis or peritoneal dialysis).
• Exposure to intravascular iodinated contrast media within the preceding 7 days.
• Hemodynamic instability, acute decompensated heart failure, or cardiogenic shock upon presentation.
• Pregnant or lactating females.
• Inability or unwillingness to comply with the 48 to 72-hour follow-up serum creatinine testing.