Purpose: Low mono-energetic images derived by Dual Energy CT (DECT) can enable greater attenuation of contrast and improve conspicuity. We hypothesized that low mono-energetic images will improve the reliability in the assessment of bowel inflammation. In this study we compared conventional abdominal contrast-enhanced CT images with the low mono-energetic and virtual-non-contrast (VNC) DECT images for contrast enhancement, contour and related findings in acute bowel inflammation.
Materials and Methods: Forty patients who underwent abdominal contrast enhanced DECT (IQon, Philips Healthcare, Eindhoven, Nederland) between January and April 2017, with radiological findings correlating to bowel inflammation were retrospectively reviewed. Contrast enhanced series were performed using conventional single-energy mode at 120 kV. VNC and mono-energetic (ME) images at 50 keV were reconstructed from the conventional study. Qualitative assessments of the inflamed bowel wall, mural or intra luminal findings, adjacent fat stranding and fluid were made on conventional, VNC and ME images and rated on a scale of 1-5 (5 being the highest). Paired t-test was used to assess the significance of the differences between the conventional, VNC and ME images.
Results: Bowel inflammation was cause by acute appendicitis (15%, 6/40), bowel obstruction (35%, 14/40), tumor (20%, 8/40) and colitis (30%, 6/40). The score of the qualitative assessment on the ME images at 50 keV (4.7) was significantly higher (p<0.001) compared to the score on the conventional image (3.9) The qualitative assessment had a lower score on the VNC image compared to the conventional image, with no significant difference.
Conclusion: Virtual low mono-energetic DECT images have the ability to significantly improve the conspicuity of acute bowel inflammation. Non-conclusive radiological studies may thus be turned into definite and clinically relevant findings.
