Non-invasive estimation of split renal function from routine ⁶⁸Ga-SSR-PET/CT scans

Area of Science:

• Nuclear medicine
• Radiopharmaceutical imaging
• Renal function assessment

Background:

• Peptide receptor radionuclide therapy (PRRT) for neuroendocrine tumors carries risks of nephrotoxicity and hematotoxicity, especially in patients with impaired kidney function.
• Somatostatin receptor (SSR)-PET/CT is crucial for identifying SSR expression, a prerequisite for PRRT.
• Accurate assessment of renal function is vital before initiating PRRT.

Purpose of the Study:

• To investigate the feasibility of evaluating split renal function using routine SSR-PET/CT imaging data prior to PRRT.
• To explore the utility of [68Ga]Ga-ha DOTATATE PET-CT scans in assessing renal function.

Main Methods:

• Retrospective analysis of 25 patients undergoing SSR-PET/CT before PRRT.
• Semi-automatic segmentation of renal parenchyma using SUV-based isocontours.
• Calculation of Accumulation Index (ACI) and Total Kidney Accumulation (TKA) from PET data, correlated with [99mTc]Tc-MAG3 scintigraphy and GFR.

Main Results:

• SUVmean of parenchymal tracer retention negatively correlated with TER_MAG and GFR.
• The developed Accumulation Index (ACI) showed significant correlations with total tubular function, glomerular renal function, and split renal function (r=0.916).
• Mean difference in split renal function between renal scintigraphy and ACI was minimal (1.8 ± 4.2 % points).

Conclusions:

• Static [68Ga]Ga-ha DOTATATE PET-scans at 32 min post-injection can estimate split renal function.
• The proposed Accumulation Index (ACI) offers a promising method for assessing both split and absolute renal function.
• This approach may aid in optimizing PRRT patient selection and management.