Adenoma characterization: adrenal protocol with dual-energy CT

Area of Science:

• Radiology
• Medical Imaging
• Endocrinology

Background:

• Adrenal masses require accurate characterization to differentiate benign adenomas from potentially malignant lesions.
• Dual-energy CT (DECT) offers advanced imaging capabilities for tissue characterization.
• Virtual unenhanced (VUE) CT techniques aim to reduce radiation dose and improve diagnostic accuracy.

Purpose of the Study:

• To evaluate the diagnostic performance of DECT using VUE CT for characterizing adrenal masses.
• To compare the accuracy of VUE CT with conventional unenhanced CT in differentiating adrenal adenoma subtypes.

Main Methods:

• A retrospective analysis of 49 patients with adrenal masses who underwent conventional unenhanced CT and DECT (80 kVp and 140 kVp) with early and delayed contrast enhancement.
• Virtual unenhanced CT images (early and delayed) were reconstructed from DECT datasets.
• Adenomas were classified as lipid-rich or lipid-poor based on attenuation values and washout characteristics.

Main Results:

• DECT with VUE CT showed higher mean attenuation values for lipid-rich adenomas on early VUE CT compared to unenhanced CT (P = .001).
• The sensitivity of VUE CT for detecting lipid-rich adenomas was 39% (early) and 61% (delayed).
• The combined DECT protocol, utilizing virtual unenhanced CT and washout rate, achieved 100% sensitivity for diagnosing all adenomas (33 of 33).

Conclusions:

• DECT with virtual unenhanced CT and washout rate effectively diagnoses lipid-poor adrenal adenomas.
• This technique may potentially miss lipid-rich adenomas, which are more reliably diagnosed using conventional unenhanced CT.
• Further refinement of DECT protocols may be necessary to improve the detection of lipid-rich adrenal adenomas.