Assessment of small bowel ischemia in mechanical small bowel obstruction: Diagnostic value of bowel wall iodine concentration using dual-energy CT

Flora Lamant; Gabriel Simon; Andreas Busse-Coté; Youness Hassoun; Bastien Roussel; Pierre Verdot; Alexandre Doussot; Zaher Lakkis; Eric Delabrousse; Paul Calame

doi:10.1016/j.diii.2024.10.009

Assessment of small bowel ischemia in mechanical small bowel obstruction: Diagnostic value of bowel wall iodine concentration using dual-energy CT

Diagn Interv Imaging. 2024 Nov 15:S2211-5684(24)00255-9. doi: 10.1016/j.diii.2024.10.009. Online ahead of print.

Affiliations

¹ Department of Radiology, University of Franche-Comté, CHRU Besançon, 25000 Besançon, France.
² Department of Digestive Surgery, University of Franche-Comté, CHRU Besançon, 25000 Besançon, France.
³ Department of Radiology, University of Franche-Comté, CHRU Besançon, 25000 Besançon, France; EA 4662 Nanomedicine Lab, Imagery and Therapeutics, University of Franche-Comté, 25000 Besançon, France.
⁴ Department of Radiology, University of Franche-Comté, CHRU Besançon, 25000 Besançon, France; EA 4662 Nanomedicine Lab, Imagery and Therapeutics, University of Franche-Comté, 25000 Besançon, France. Electronic address: p1calame@chu-besancon.fr.

PMID: 39550287
DOI: 10.1016/j.diii.2024.10.009

Abstract

Purpose: The purpose of this study was to determine whether dual-energy computed tomography (DECT), specifically by measuring bowel wall iodine concentration (BWIC), is superior to monoenergetic reconstructions (MR) for the diagnosis and staging of small bowel ischemia in patients with mechanical small bowel obstruction (SBO).

Materials and methods: From November 2021 to December 2023, all patients with mechanical SBO who underwent contrast-enhanced DECT of the abdomen and pelvis were evaluated for inclusion. Demographic, clinical and biochemical data were collected. Two abdominal radiologists, blinded to all patient information, reviewed all DECT examinations. Conventional CT features (including a closed loop mechanism, mesenteric haziness, decreased bowel wall enhancement (DBE), and increased unenhanced attenuation of the bowel wall) were first reviewed on 70-keV-MR and 40-keV-MR, followed by BWIC measurements in five regions of interest in the walls of both normal and abnormal small bowel loops. The diagnostic performance of a simple CT score, which included a closed loop mechanism, mesenteric haziness and DBE, was compared to that of BWIC measurements made on dilated and/or abnormal small bowel segments for the diagnosis of small bowel ischemia. The diagnostic capabilities were compared using areas under the receiver operating characteristic curves (AUCs).

Results: A total of 142 patients were included (80 men, 62 women; mean age, 67 ± 17 [standard deviation (SD)] years). Fifty-six patients underwent surgery; 22 of them had confirmed small bowel ischemia, including 12 patients with small bowel necrosis requiring surgical resection. Significant differences in mean BWIC were found between patients without small bowel ischemia (1.73 ± 0.44 [SD] mg/mL), those with small bowel ischemia without necrosis (0.79 ± 0.37 [SD] mg/mL), and those with small bowel ischemia and necrosis (0.48 ± 0.32 [SD] mg/mL) (P < 0.001). The overall AUC of the BWIC measurement for diagnosing small bowel ischemia was 0.98 (95 % confidence interval [CI]: 0.97-1.00), similar to the AUC of the simple CT score (0.97; 95 % CI: 0.92-1.00). However, using a cut off-value of 1.16 mgI/mL, BWIC outperformed subjective assessment of DBE at 70-keV-MR and 40-keV-MR (Youden index, 0.90 vs. 0.54 and vs. 0.71, respectively) (P < 0.001 for both).

Conclusion: BWIC measurement outperforms subjective assessment of DBE for the diagnosis of small bowel ischemia in patients with SBO and can allow stratification of ischemia. However, BWIC does not outperfomr a global comprehensive analysis of conventional CT images.

Keywords: Dual energy CT; Intestinal obstruction; Iodine; Small bowel ischemia; Small bowel necrosis.