Comparison of CT scans with and without contrast in the characterization of adrenal gland adenomas

Introduction: With the increased use of diagnostic procedures such as computed tomography (CT), the detection of asymptomatic adrenal lesions demonstrates a growing trend. Accurately distinguishing these lesions is essential for guiding future diagnostic and treatment approaches. Aim: This study aimed to investigate whether it is possible to determine the adenomatous characteristics of adrenal tumors on non-contrast CT scans. Material and Method: A retrospective observational study was conducted at the University Clinical Center of Vojvodina (UKCV), involving 43 patients who underwent CT imaging following the adrenal protocol. The key parameters examined were: sex, age, antero-posterior (AP) and latero-lateral diameter (LL) of the adenoma, non-contrast density, absolute (APW) and relative (RPW) washout. Results: Our study has shown a statistically significant negative correlation between non-contrast density and RPW (p<0.001), as well as significant positive correlation between APW and RPW (p=0.007). The non-contrast density demonstrated a statistically significant positive correlation with the AP diameter of the adenoma (p=0.035). Conclusion: Our research shows that when using unenhanced CT imaging, a non-contrast density significantly below 10 Hounsfield units (HU) and a lesion diameter under 40 mm strongly suggest an adrenal gland adenoma, potentially allowing for diagnosis without multiple scans or contrast.