Comparing the Reliability of the Glomerular Filtration Rate Estimated with 99m-Technetium Diethylene-Triamine-Pentaacetate versus the Effective Renal Plasma Flow Obtained with 99m-Technetium Ethylene Dicysteine: A Prospective Observational Study

by Selleckchem | Feb 16 2024

The glomerular filtration rate (GFR) is important for assessing renal function and must be calculated reliably and reproducibly. This study aimed to compare the reliability and accuracy of GFR estimated with 99m-technetium diethylene-triamine-pentaacetate (99mTc-DTPA) versus that calculated from the effective renal plasma flow (ERPF) (GFR is 20% of ERPF) determined by the 99m-technetium ethylene dicysteine (99mTc-EC) technique. Forty-five patients suffering from cancer requiring platinum compound-based chemotherapy or from chronic renal failure were recruited. The patients were divided into two cohorts: (1) those with normal serum creatinine (SCr) levels (≤2 mg/dL) and (2) deranged SCr levels (>2 mg/dL). For all patients, the relative renal function was estimated by the 99mTc-DTPA and 99mTc-EC methods, 2-4 days apart. A 24-h urine sample for estimating 24-h creatinine clearance (CrCl) was obtained. GFR was also calculated using the Modification of Diet in Renal Disease (MDRD) formula. The GFR estimated via 24-h urine CrCl, 99mTc-DTPA, and ERPF obtained with 99mTc-EC were examined by quantile comparison plots, and all showed evidence of following a non-Gaussian distribution. For SCr values ≤2 mg/dL, the GFR estimated by the MDRD formula consistently shows significantly higher values than the GFR estimated with 99mTc-DTPA or 99mTc-EC. We found a high degree of correlation between the 99mTc-DTPA and 99mTc-EC radionuclide methods of estimating GFR. However, in patients with renal dysfunction, GFR estimated through Gates' method using a gamma camera overestimated the GFR; in these patients, calculating the GFR from the ERPF obtained with 99mTc-EC is more accurate.

Comments:

The study you're discussing seems focused on evaluating different methods to estimate glomerular filtration rate (GFR) in patients with various kidney conditions or undergoing specific cancer treatments. It's essentially comparing the accuracy and reliability of different techniques for measuring GFR.

Here's a breakdown of the key points in the study:

1. **Objective:** To compare the reliability and accuracy of GFR estimated with two different techniques: 99m-technetium diethylene-triamine-pentaacetate (99mTc-DTPA) and effective renal plasma flow (ERPF) determined by the 99m-technetium ethylene dicysteine (99mTc-EC) technique.

2. **Study Population:** 45 patients with cancer requiring platinum-based chemotherapy or chronic renal failure.
- Subdivided into two groups based on serum creatinine (SCr) levels: normal (≤2 mg/dL) and elevated (>2 mg/dL).

3. **Methods Used:**
   - GFR estimation through 99mTc-DTPA and 99mTc-EC methods, performed 2-4 days apart for each patient.
   - Collection of 24-hour urine samples for creatinine clearance (CrCl) estimation.
   - GFR calculation using the Modification of Diet in Renal Disease (MDRD) formula.

4. **Results:**
   - GFR estimates via 24-hour urine CrCl, 99mTc-DTPA, and ERPF using 99mTc-EC showed non-Gaussian distributions.
   - For patients with SCr values ≤2 mg/dL, the GFR estimated by the MDRD formula consistently showed significantly higher values compared to 99mTc-DTPA or 99mTc-EC.
   - A high correlation was observed between 99mTc-DTPA and 99mTc-EC methods for estimating GFR.
   - In patients with renal dysfunction, the GFR estimated through Gates' method using a gamma camera tended to overestimate GFR. In such cases, calculating GFR from ERPF obtained with 99mTc-EC was deemed more accurate.

In summary, the study suggests that in patients with renal dysfunction, calculating GFR from ERPF obtained with 99mTc-EC might be more accurate than some other methods, particularly in comparison to Gates' method using a gamma camera, which tends to overestimate GFR in these patients. This highlights the importance of selecting the most appropriate method based on the patient's condition for accurate GFR estimation.