C-X-C Motif Chemokine Receptor 4–Directed Scintigraphy Using [99mTc]Tc-Pentixatec in Primary Aldosteronism: A Proof-of-Concept Study

C-X-C motif chemokine receptor 4 (CXCR4)-directed imaging has gained clinical interest in aiding clinical diagnostics in primary aldosteronism (PA). We retrospectively evaluated the feasibility of CXCR4-directed scintigraphy using the novel CXCR-4 ligand [^99mTc]Tc-pentixatec in patients with PA. Methods: Six patients (mean age ± SD, 49 ± 15 y) underwent CXCR4-directed scintigraphy (including planar imaging and SPECT/CT) 30, 120, and 240 min after injection of 435 ± 50 MBq of [^99mTc]Tc-pentixatec. Adrenal CXCR4 expression was analyzed by calculating lesion-to-contralateral ratios (LCRs). Imaging results were correlated to clinical information. Histopathology and clinical follow-up served as the standard of reference. Results: Three subjects showed lateralization of adrenal tracer accumulation, with a mean maximum lesion-to-contralateral ratio of 1.65 (range, 1.52-1.70), which correlated with morphologic findings on CT. One individual underwent adrenalectomy and presented with complete biochemical and clinical remission at follow-up. Histopathologic workup confirmed unilateral aldosterone-producing adenoma. Conclusion: [^99mTc]Tc-pentixatec scintigraphy with SPECT in patients with PA is feasible and might offer a valuable alternative to CXCR4-directed imaging with [⁶⁸Ga]Ga-pentixafor PET.