Prediction model for irreversible intestinal ischemia in strangulated bowel obstruction

External validation of a CT score for predicting ischaemia in adhesive small-bowel obstruction

OBJECTIVES

To assess the diagnostic accuracy, in a validation cohort, of a score based on three CT items, which has shown good performance for predicting ischaemia complicating acute adhesive small-bowel obstruction (SBO).

METHODS

This retrospective single-centre study of diagnostic accuracy included consecutive patients admitted for acute adhesive SBO in 2015-2022, who were treated conservatively or underwent surgery within 24 h after CT. The gold standard for ischaemia was an intraoperative diagnosis for operated patients, while the absence of ischaemia was confirmed either by its absence during surgery or by clinical follow-up in patients who did not undergo surgery. Three radiologists independently assessed the three score items, namely, decreased bowel-wall enhancement, diffuse mesenteric haziness, and closed-loop mechanism. Inter-observer agreement was evaluated by computing Fleiss' kappa. The diagnostic performance characteristics of the score were computed.

RESULTS

Of the 164 patients analysed (median age, 70 [57-80] years; 88 [54%] males), 57 (34.8%) had surgery, including 41 (71.9%) with intra-operative evidence of bowel ischaemia, whereas 107 (65.2%) were treated conservatively. A score ≥ 2/3 had a sensitivity of 78% (95% CI: 62-89%), a specificity of 97% (95% CI: 92-99%), a positive predictive value of 89% (95% CI: 74-97%), and a positive likelihood ratio of 24 (95% CI: 9.03-63.79). Adding increased unenhanced bowel-wall attenuation and requiring ≥ 2/4 items did not improve score performance. Fleiss' kappa values indicated moderate to substantial agreement between observers: 0.64 [0.56-0.73] for decreased bowel-wall enhancement, 0.57 [0.48-0.66] for diffuse mesenteric haziness, and 0.68 [0.59-0.76] for closed-loop mechanism.

CONCLUSIONS

The results of this external validation study support the reproducibility and good diagnostic performance of the score based on three CT items for predicting bowel ischaemia complicating acute adhesive SBO.

KEY POINTS

Question The Millet score with three enhanced CT items for predicting bowel ischaemia complicating acute adhesive SBO has not been assessed in an external validation cohort. Findings Adding "increased unenhanced bowel-wall attenuation" to the "decreased bowel-wall enhancement", "diffuse mesenteric haziness", and "closed-loop mechanism" items did not improve score performance. Clinical relevance In an external validation cohort, a score based on three CT items performed well for predicting ischaemia in patients with acute adhesive SBO and showed acceptable inter-observer agreement. This score may help identify patients for surgery.

Diagnosis of necrotic and non-necrotic small bowel strangulation: The importance of intestinal congestion

Background

Despite the prevalence of laparoscopic techniques in abdominal surgeries today, bowel obstruction remains a potentially serious complication. Small bowel strangulation (SBS), in particular, is a critical condition that can lead to patient mortality. However, the prognosis for SBS is favorable if surgery is performed before the onset of necrosis. Non-necrotic SBS is a reversible condition in which blood flow can be restored by relieving the strangulation. The purpose of this study was to identify sensitive and specific contrast-enhanced computed tomography (CT) findings that are useful for diagnosis of both non-necrotic and necrotic SBS.

Methods

We included patients diagnosed with SBS and simple bowel obstruction (SBO) who underwent contrast-enhanced CT followed by surgery from 2006 to 2023. Two gastrointestinal surgeons independently assessed the images retrospectively.

Results

Eighty SBO and 141 SBS patients were included. Eighty-seven had non-necrotic SBS and 54 had necrotic SBS. Mesenteric edema was most frequently observed in both necrotic and non-necrotic SBS cases followed by abnormal bowel wall thickening. These two findings were observed significantly less frequently in SBO. Bowel hypo-enhancement is identified in only about half of the non-necrotic SBS cases, and it was detected at significantly higher rates in necrotic SBS compared to non-necrotic.

Conclusion

Mesenteric edema and abnormal bowel wall thickening are sensitive and specific signs of both non-necrotic and necrotic SBS. These two findings indicate mesenteric and bowel congestion. Detecting intestinal congestion can lead to an accurate diagnosis of SBS, particularly in case of non-necrotic SBS, where bowel hypo-enhancement may sometimes be absent.

Radiological diagnosis of acute mesenteric ischemia in adult patients: a systematic review and meta-analysis

Computed tomography (CT) is widely used in diagnosing acute mesenteric ischemia (AMI), but robust identification of distinctive subtypes and stages of progression is lacking. Systematic literature search in PubMed, Cochrane Library, Web of Science and Scopus was conducted in May 2024. Studies including at least 10 adult patients and reporting radiological diagnosis of AMI versus no AMI or transmural ischemia versus no transmural ischemia were included. Meta-analyses on sensitivity and specificity of different radiological features in diagnosing AMI were conducted. From 2628 titles, 490 studies underwent full text review, and 81 were included in 14 meta-analyses. Diagnostic accuracy of CT angiography (CTA) was high - sensitivity of 92.0% and specificity of 98.8% (I2 45% and 79%, respectively), but lower for other CT protocols (sensitivity 75.8 and specificity 90.5; I2 83%). In most included studies, distinction of subtypes and severity of AMI (non-transmural or transmural) was not possible. Amongst the non-vascular features, absent/reduced bowel wall enhancement provided the best prognostic value (sensitivity 57.9 and specificity 90.1). CTA is the method of choice for diagnosing AMI with high diagnostic accuracy. None of the non-vascular features alone is sufficiently reliable to diagnose AMI or its progression to transmural necrosis, whereas a combination of different radiological features conveys a potential.

Development and validation of a CT-based radiomic nomogram for predicting surgical resection risk in patients with adhesive small bowel obstruction

BACKGROUND

Adhesive small bowel obstruction (ASBO) is a common emergency that requires prompt medical attention, and the timing of surgical intervention poses a considerable challenge. Although computed tomography (CT) is widely used, its effectiveness in accurately identifying bowel strangulation is limited. The potential of radiomics models to predict the necessity for surgical resection in ASBO cases is not yet fully explored.

OBJECTIVES

The aim of this study is to identify risk factors for surgical resection in patients with ASBO and to develop a predictive model that integrates radiomic features with clinical data. This model designed to estimate the likelihood of surgical intervention and aid in clinical decision-making for acute ASBO cases.

METHODS

From January 2019 to February 2022, we enrolled 188 ASBO patients from our hospital, dividing them randomly into a training cohort (n = 131) and a test cohort (n = 57) using a 7:3 ratio. We collected baseline clinical data and extracted radiomic features from CT images to compute a radiomic score (Rad-score). A nomogram was developed that combines clinical characteristics and Rad-score. The performance of clinical, radiomic, and combined nomogram models was evaluated in both cohorts.

RESULTS

Of the 188 patients, 92 underwent surgical resection, while 96 did not. The nomogram integrated factors such as white blood cell count, duration of obstruction, and preoperative infection indicators (fever, tachycardia, peritonitis), along with CT findings (elevated wall density, thickened wall, mesenteric fluid, ascites, bowel wall gas, small bowel feces, and hyperdensity of mesenteric fat) (p < 0.1). This combined model accurately predicted the need for surgical resection, with area under the curve (AUC) values of 0.761 (95% CI, 0.628-0.893) for the test cohort. Calibration curves showed strong agreement between predicted and observed outcomes, and decision curve analysis validated the model's utility for acute ASBO cases.

CONCLUSION

We developed and validated a CT-based nomogram that combines radiomic features with clinical data to predict the risk of surgical resection in ASBO patients. This tool offers valuable support for treatment planning and decision-making in emergent situations.

The value of D-dimer and platelet-lymphocyte ratio combined with CT signs for predicting intestinal ischemia in patients with bowel obstruction

OBJECTIVE

To investigate the diagnostic value of D-dimer, platelet-lymphocyte rate (PLR) and CT signs for intestinal ischemia in patients with bowel obstruction.

METHODS

We retrospectively analyzed the clinical and imaging data of 105 patients diagnosed with bowel obstruction, and performed univariate and multivariate analyses to determine the independent risk factors for intestinal ischemia in patients with bowel obstruction. Moreover, the receiver operating characteristic curve (ROC) was plotted to examine the diagnostic value of D-dimer, PLR and CT signs in patients with bowel obstruction. Besides, Kappa tests were used to assess inter-observer agreement.

RESULTS

We included 56 men (53%) and 49 women (47%) with mean age of 66.05 ± 16 years. Univariate and multivariate analyses showed that D-dimer, PLR and two significant CT signs (i.e., increased unenhanced bowel-wall attenuation and mesenteric haziness) were independent risk factors for intestinal ischemia in patients with bowel obstruction. ROC analysis showed that the combined use of D-dimer, PLR and the said two CT signs had better performance than single indicators in predicting intestinal ischemia in patients with bowel obstruction. The area under the curve (AUC) of the joint model III was 0.925 [95%CI: 0.876-0.975], with a sensitivity of 79.2% [95CI%: 67.2-91.1] and a specificity of 91.2% [95%CI: 83.7-98.9].

CONCLUSION

The combined use of D-dimer, PLR and CT signs has high diagnostic value for intestinal ischemia in patients with bowel obstruction and will prompt surgical exploration to evaluate intestinal blood flow.

The target sign: a significant CT sign for predicting small-bowel ischemia and necrosis

OBJECTIVE

To investigate the correlation between changes in the thickness and density of diseased small-bowel wall and small-bowel ischemia and necrosis (SBN) on CT imaging when small-bowel obstruction (SBO) occurs.

METHODS

We retrospectively analyzed 186 patients with SBO in our hospital from March 2020 to June 2023. The patients were divided into simple SBO (control group) and SBN (case group) groups. We used logistic regression analysis, the chi-square test, and Fisher's exact test to analyze the correlation between the changes in the thickness and density of the diseased intestinal wall and the SBN. A receiver operating characteristic (ROC) curve was used to calculate the accuracy of the multivariate analysis.

RESULTS

Of the 186 patients with SBO, 98 (52.7%) had simple SBO, 88 (47.3%) had SBN, and the rate of SBN was 47.3% (88/186). Multivariate regression analysis revealed that six CT findings were significantly correlated with SBN (p < 0.05), namely, thickening of the diseased intestinal wall with the target sign (OR = 21.615), thinning of the diseased intestinal wall (OR = 48.106), increase in the diseased intestinal wall density (OR = 13.696), mesenteric effusion (OR = 21.635), decrease in the diseased intestinal wall enhancement on enhanced scanning (OR = 41.662), and increase in the diseased intestinal wall enhancement on enhanced scanning (OR = 15.488). The AUC of the multivariate analysis reached 0.987 (95% CI 0.974-0.999). Specifically, the target sign was easily recognizable on CT images and was a significant CT finding for predicting SBN.

CONCLUSION

We identified 6 CT findings that were significantly associated with SBN, and may be helpful for clinical treatment.

Diagnosis and surgical management strategy for pediatric small bowel obstruction: Experience from a single medical center

Identifying Bowel strangulation and the approach and timing of surgical intervention for pediatric SBO are still uncertain. In this study, 75 consecutive pediatric patients with surgically confirmed SBO were retrospectively reviewed. The patients were divided into group 1 (n = 48) and group 2 (n = 27) according to the presence of reversible or irreversible bowel ischemia, which was analyzed based on the degree of ischemia at the time of operation. The results demonstrated that the proportion of patients with no prior abdominopelvic surgery was higher, the serum albumin level was lower, and the proportion of patients in which ascites were detected by ultrasonography was higher in group 2 than that in group 1. The serum albumin level was negatively correlated with ultrasonographic findings of the fluid sonolucent area in group 2. There were significant differences in the choice of surgical approach between group 1 and group 2. A symptom duration of >48 h was associated with an increased bowel resection rate. The mean length of hospital stay was shorter in group 1 than that in group 2. In conclusion, immediate surgical intervention should be considered in patients with a symptom duration of >48 h or the presence of free ascites between dilated small bowel loops on ultrasonography. Laparoscopic exploration is recommended as first-line treatment in patients with stable status.