Non-Invasive Early Detection of Tubular Atrophy and Interstitial Fibrosis in Immunoglobulin A Nephropathy Using [¹⁸F]...

Area of Science:

• Nephrology
• Nuclear Medicine
• Radiochemistry

Background:

• Immunoglobulin A nephropathy (IgAN) is the most prevalent primary glomerulonephritis globally.
• Tubular atrophy and interstitial fibrosis (TAIF) are key indicators of IgAN progression.
• Non-invasive methods for assessing TAIF are crucial for early intervention.

Purpose of the Study:

• To assess the efficacy of [¹⁸F] AlF-NOTA-FAPI-04 PET/CT in non-invasively predicting TAIF in IgAN patients.
• To evaluate the performance of this imaging modality, particularly in early-stage IgAN with preserved renal function.

Main Methods:

• Thirty-one IgAN patients underwent renal biopsy and [¹⁸F] AlF-NOTA-FAPI-04 PET/CT.
• Patients were classified based on TAIF severity (T0 vs. T1/T2).
• Renal parenchymal uptake (SUVmax, SUVmean) was correlated with histological findings and FAP/α-SMA expression.

Main Results:

• Higher FAPI uptake (SUVmax, SUVmean) was observed in patients with more severe TAIF (T1/T2 vs. T0, p < 0.01).
• SUVmax and SUVmean demonstrated high accuracy (AUC 0.870 and 0.859, respectively) in identifying TAIF.
• Diagnostic performance remained high (AUC 0.900) even in patients with normal renal function.

Conclusions:

• [¹⁸F] AlF-NOTA-FAPI-04 PET/CT effectively quantifies TAIF in IgAN non-invasively.
• The technique maintains diagnostic accuracy in patients with normal renal function, enabling early risk stratification.
• This PET/CT approach supports timely therapeutic interventions for IgAN progression.