For noninvasively predicting renal response to lupus nephritis induction therapy, the radiotracer fibroblast activation protein inhibitor (FAPI) may outperform renal cortical fluorodeoxyglucose (FDG) for positron emission tomography/computed tomography (PET/CT) imaging, according to investigators. At 6 months after induction therapy, 50% of patients had complete response, 25% partial response, and 25% nonresponse. The 89% of patients with negative baseline FAPI PET/CT achieved a complete response, compared with 64% of FDG-negative patients. Further analysis showed that compared with nonresponders, complete responders had a significantly lower baseline renal FAPI SUVmax and target-to-background ratio (P<0.01). Radiologists’ visual assessment of FAPI uptake in the renal parenchyma also outperformed FDG uptake in predicting complete response.