Low-keV virtual monoenergetic images with rapid kilovoltage-switching DECT for differentiating complicated from uncomplicated appendicitis in adults

Abstract

Objectives: Low-keV virtual monoenergetic images on dual-energy CT (DECT) enhance iodine attenuation in inflamed appendiceal walls, but the role in differentiating complicated from uncomplicated appendicitis remains unclear. This is particularly relevant given the shift toward nonoperative management of uncomplicated appendicitis. Methods: Consecutive adult patients with pathologically confirmed acute appendicitis who underwent preoperative rapid-kVP-switching DECT and appendectomy within 24 h were retrospectively included. Two radiologists reviewed DECT images, including a finding of appendiceal wall enhancement defects, using three series: 50-keV monoenergetic, 120-kVp-equivalent, and combined series, with discrepancies resolved by a third radiologist. Diagnostic performance of three series for differentiating complicated from uncomplicated appendicitis was assessed. Detection rates of appendiceal wall enhancement defects and radiologist confidence among three series were compared. Results: Among 155 patients (50 men, mean age 47.4±19.0 years), 59 had complicated appendicitis. The combined 50-keV/120-kVp-equivalent series provided balanced sensitivity (83.1%) and specificity (86.5%), with an accuracy of 85.2% in differentiating uncomplicated and complicated appendicitis. Although 50-keV images revealed the most wall enhancement defects (48/122; 39.3%), radiologists’ confidence was significantly higher using the combined series (91.8% vs. 72.1%, p < 0.001). Conclusions: Low-keV virtual monoenergetic DECT, when combined with 120-kVP-equivalent images, improved the detection of appendiceal wall enhancement defects and increased radiologist confidence in differentiating complicated from uncomplicated appendicitis in adult patients with acute appendicitis.