Differentiation between benign and malignant adrenal mass using contrast-enhanced ultrasound

Adrenal masses can be detected by ultrasound with high sensitivity and specificity. The aim of the present study was to evaluate CEUS in a large patient population using CEUS patterns identified in a previous pilot study.

116 adrenal masses were evaluated by ultrasound, including CEUS with the contrast agent Sonovue®. The dynamic of contrast enhancement (CE) was analyzed using time-intensity curves. The time of the first CE in the adrenal mass was used to define four CEUS patterns: pattern I = early arterial CE, pattern II = arterial CE, pattern III = late CE, pattern IV = no CE. In addition, all patients received CT/MRI and hormonal testing. In suspicious cases biopsy or adrenalectomy was performed.

CEUS patterns I&II were seen in all patients with primary or secondary malignant lesions of the adrenal gland (n = 16). The sensitivity and specificity of CEUS for the diagnosis of malignant adrenal mass were 100 % (CI [75;100]) and 67 % (CI [56;75]), respectively. Overall histology was available as a reference method for 40 adrenal masses. In 68 % of histologically diagnosed adrenal masses, MRI/CT and CEUS were congruent concerning the characterization of malignant versus benign adrenal mass.

Contrast-enhanced ultrasound may be a useful method in the diagnostic work-up of adrenal mass with excellent sensitivity for the diagnosis of malignancy.