Dual energy CT in acute appendicitis: value of low mono-energy

Naama Lev-Cohain*, Jacob Sosna, Yuval Meir, Gili Dar, Noam Shussman, Isaac Leichter, Nadia Caplan, S. Nahum Goldberg

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Objectives: To assess the potential role of low monoenergetic images in the evaluation of acute appendicitis. Methods: A retrospective study of 42 patients with pathology proven acute appendicitis underwent contrast-enhanced-CT conducted on a single-source-DECT before surgery. Attenuation, SNR, and CNR were calculated on both monoenergetic and conventional images and compared to 24 abdominal CT-scans with normal appendix. Representative conventional and monoenergetic images were randomized and presented side-by-side to three abdominal radiologists to determine preferred images for detecting inflammation. Additionally, six individual acute inflammatory characteristics were graded on a 1–5 scale to determine factors contributing to differences between conventional and monoenergetic images by 2 abdominal radiologists. Paired t-tests, Wilcoxon and McNemar tests, and intra-observer error statistics were performed. Results: For the inflamed appendixes monoenergetic images had overall increased attenuation (average ratio 1.7; P < 0.05), signal-to-noise-ratio (6.7 ± 3.1 vs 4.2 ± 1.6; P < 0.001) and contrast-to-noise-ratio (12.1 ± 3 vs 9 ± 2.1; P < 0.001). Moreover, this increase was not found in normal appendixes (P < 0.001 vs p = 0.28–0.44). Subjectively, radiologists showed significant preferences towards monoenergetic images (P < 0.001), with inter-reader agreement of 0.84. Two parameters, diffuse bowel wall and mucosal enhancement, received significantly higher scores on monoenergetic images (average 4.3 vs. 3.0; P < 0.001 and 2.8 vs. 2.3 P < 0.03 respectively, with interobserver agreements of 62% and 52%). Conclusion: Increased bowel wall conspicuity from enhanced attenuation, SNR, and CNR on low monenergetic CT images results in a significant preference by radiologists for these images when assessing acute inflamed appendixes. Thus, close inspection of low monoenergetic images may improve the visualization of acute inflammatory bowel processes.

Original languageAmerican English
Pages (from-to)213-218
Number of pages6
JournalClinical Imaging
StatePublished - Sep 2021

Bibliographical note

Publisher Copyright:
© 2021 Elsevier Inc.


  • Appendicitis
  • Bowel inflammation
  • Contrast-to-noise-ratio
  • Dual-energy CT
  • Signal-to-noise-ratio


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