Adrenal Cortical Imaging With I-131 NP-59 SPECT-CT

Purpose: The purpose of this article is to present our initial experience with hypersecretory adrenal syndromes investigated with radioiodinated I-6-B-iodomethyl-19-norcholesterol (NP-59) and SPECT-CT. Materials and Methods: Illustrative cases are presented of patients being investigated for adrenal hypersecretory syndromes, with or without adrenal nodules, using NP-59 scintigraphy with SPECT-CT imaging, representing a spectrum of diagnoses. Clinical and imaging data are reviewed to evaluate whether additional information derived from near-simultaneous anatomic localization aids study interpretation. Results: The final diagnoses reached are hyperfunctional and nonfunctioning adrenal nodules, physiological bowel activity, and bilateral adrenal hyperplasia. SPECT-CT assisted study interpretation by localizing focal uptake to the adrenal glands, allowing direct assessment of function within adrenal nodules, and distinguishing physiological bowel activity from adrenal uptake. SPECT-CT provided additional information to planar and SPECT imaging, which improved confidence of study interpretation. Conclusion: Utilization of SPECT-CT with NP-59 scintigraphy allows precise localization of the functional activity to anatomic structures improving diagnostic interpretation.