Intravenous Contrast Agent in Abdominal CT: Is It Really Needed to Identify the Cause of Bowel Obstruction? Proof of Concept

Unenhanced CT-based predictive model to identify small bowel necrosis in patients with mechanical small bowel obstruction

OBJECTIVES

To investigate the diagnostic value of unenhanced CT in mechanical small bowel obstruction (SBO) with small bowel necrosis, and to establish a predictive model.

METHODS

From May 2017 to December 2021, the patients with mechanical SBO admitted to our hospital were retrospectively collected. Taking pathology-confirmed small bowel necrosis as the gold standard, the experimental group was composed of patients with small bowel necrosis confirmed by pathology, and the control group was composed of patients with no intestinal necrosis confirmed by surgery or successful conservative treatment with no recurrence of intestinal obstruction during 1-month followed-up.

RESULTS

A total of 182 patients were enrolled in this study, 157 patients underwent surgery, of which 35 patients were accompanied with small bowel necrosis and 122 patients were not (33 patients with ischemic findings at surgery without necrosis). Finally, there were 35 patients in the experimental group and 147 patients in the control group. Multivariable logistic regression showed that increased attenuation of small bowel wall (P = 0.002), diffuse mesenteric haziness (P = 0.010), difference of CT value between mesenteric vessel and aorta (P = 0.025) and U-/C-shaped small bowel loop (P = 0.010) were independent risk factors for the diagnosis of mechanical SBO with small bowel necrosis. Through internal verification, the area under curve (AUC) of the predictive model reached 0.886 (95%CI: 0.824-0.947), and the calibration result was moderate.

CONCLUSION

Multiple features (increased attenuation of small bowel wall; difference of CT values between mesenteric vessel and aorta; diffuse mesenteric haziness; and U-/C-shaped small bowel loop) of unenhanced CT have clinical value in the diagnosis of mechanical SBO with small bowel necrosis. The predictive model based on these four features could achieve satisfactory efficiency.

Intestinal fatty acid-binding protein as a biomarker for the diagnosis of strangulated intestinal obstruction: A meta-analysis

Objective

The purpose of this study was to clarify the value of intestinal fatty acid-binding protein (I-FABP) for the early diagnosis of strangulated intestinal obstruction through a meta-analysis.

Methods

A search was performed on PubMed, EBSCO, the Cochrane Library, the Web of Science, EMBASE, CNKI, and WanFang for studies on the diagnosis of strangulated intestinal obstruction based on I-FABP. Endnote X9 software and the quality assessment of diagnostic accuracy studies 2 (QUADAS-2) were used to screen the studies and evaluate their quality, respectively. Meta-Disc 1.4 and Stata 15.1 software were used to perform the assessment of heterogeneity and meta-analysis.

Result

A total of eight studies were included, Spearman correlation coefficient was 0.703 (P = 0.078), suggesting that there was no threshold effect. The pooled results of the meta-analysis were as follows: sensitivity: 0.75 (95% CI: 0.66–0.81), specificity: 0.83 (95% CI: 0.71–0.91), positive likelihood ratio (PLR): 4.35 (95% CI: 2.57–7.36), negative likelihood ratio (NLR): 0.31 (95% CI: 0.24–0.39), and diagnostic odds ratio (DOR): 14.19 (95% CI: 8.08–24.92). The area under the curve was 0.83. There was obvious heterogeneity among the studies.

Conclusion

I-FABP is very valuable for the early diagnosis of strangulated intestinal obstruction and can be used to distinguish strangulated intestinal obstruction from intestinal obstruction in a timely manner, enabling accurate planning of the timing of surgery.