Nakajo M, Jinguji M, Tani A, et al. - In the present study, the researchers sought to assess the maximum standardized uptake value (SUVmax) by ¹³¹I-6β-iodomethyl-19-norcholesterol (NP-59) single-photon emission computed tomography (SPECT)/computed tomography (CT) for describing unilateral hyperfunctioning adrenocortical masses. Ten patients had NP-59 SPECT/CT to assess the following unilateral adrenocortical hyperfuncting masses: three with Cushing’s syndrome (CS), three with subclinical CS, and four with primary aldosteronism (PA). Data reported that the area under the ROC curve and precision for differentiating between CS and PA were 0.92 and 90.0% for the lesion SUVmax, 1.00 and 100% for the contralateral SUVmax, and 0.92 and 90.0% for the SUVmax ratio, respectively. Quantitative or semiquantitative analysis using the adrenal SUVmax in adrenocortical NP-59 SPECT/CT has the ability to characterize unilateral hyperfunctioning adrenocortical masses.