The Study on the Effectiveness of [68Ga]Ga-HBED-CC-DiAsp PET/CT in Calculating GFR and Predicting Residual Renal Function After Partial Nephrectomy

[68Ga]Ga-HBED-CC-DiAsp PET/CT Imaging: After intravenous injection of [68Ga]Ga-HBED-CC-DiAsp, a Scout scan, low-dose CT scan, and a 30-minute dynamic PET scan are performed sequentially. The functional renal cortex is delineated in the first PET frame showing the radiotracer filling the renal cortex. A functional renal cortex radioactivity concentration function is constructed based on a compartment model with GFR as a parameter and time as an independent variable. This function is then fitted to the time-activity curve (TAC) of the functional renal cortex to obtain the GFR value.

Gates Method and 99mTc-DTPA Dual Plasma Method: After intravenous injection of 99mTc-DTPA, renal blood flow functional imaging is performed immediately, collecting time-activity curves from both renal areas. GFR is calculated based on the percentage (%ID) of bilateral renal radiotracer uptake relative to the injected dose. Blood samples of 10 ml are collected from the contralateral forearm at 1 hour and 2 hours post-injection, and GFR is calculated using the dual plasma method.

In subjects with different levels of renal function and no history of renal tumors, GFR is measured using [68Ga]Ga-HBED-CC-DiAsp PET/CT, the Gates method, and the 99mTc-DTPA dual plasma method. The consistency between the three methods is analyzed using intra-class correlation coefficient (ICC), concordance correlation coefficient (CCC), and Bland-Altman analysis.

In patients scheduled for partial nephrectomy due to renal tumors, GFR is measured using the three methods within 2 weeks before surgery and 4±1 weeks post-surgery. The percentage of postoperative residual renal function (postoperative GFR/preoperative GFR × 100%, hereafter referred to as RRF%) is calculated for each method. By comparing and overlaying preoperative and postoperative PET/CT images, the resected renal area can be delineated on the preoperative PET/CT image. Based on the preoperative PET/CT and the delineated surgical area, a predictive value for postoperative GFR is calculated to obtain the predicted RRF%. A consistency analysis is then performed between the predicted RRF% and the actual RRF% measured by the three methods, using ICC, CCC, and Bland-Altman analysis to evaluate the efficacy of [68Ga]Ga-HBED-CC-DiAsp PET/CT in predicting residual renal function after partial nephrectomy.

Inclusion criteria

• Age > 18 years;
• Written informed consent obtained.

Exclusion criteria

• Patients with claustrophobia or fear of radiation;
• Women who are planning to conceive, pregnant, or breastfeeding;
• Patients unable to lie flat for 30 minutes;
• Patients or family members who cannot understand the conditions and objectives of the study, or who refuse to participate.