External validation of a CT score for predicting ischaemia in adhesive small bowel obstruction Vadot, V., Guiraud, A., Kalilou Sow, A. et al. External validation of a CT score for predicting ischaemia in adhesive small-bowel obstruction. Eur Radiol (2025). doi.org/10.1007/s00330-025-11362-1 Acute small bowel obstruction (SBO) is a frequent cause of emergency hospital admissions, with adhesions responsible for over 65% of cases. While most cases can be managed conservatively, timely identification of bowel ischaemia is crucial, as it requires immediate surgical intervention. Contrast-enhanced computed tomography (CT) is the primary imaging tool for diagnosing SBO and assessing ischaemia, with high sensitivity and specificity. The present study aimed to externally validate the Millet score (primary objective) and assess whether adding increased unenhanced bowel-wall attenuation could improve its predictive performance (secondary objective). Authors reviewed data from patients admitted with SBO at a University Hospital between 2015 and 2021. The inclusion criteria were: Age ≥ 18 years; Confirmed acute adhesive SBO (all medical, surgical, radiological and pathological information was reviewed collaboratively by an experienced gastrointestinal radiologist and surgeon); Availability of a CT scan with both unenhanced and portal-phase contrast-enhanced acquisitions. Exclusion criteria included colonic obstruction, functional ileus, mesenteric ischaemia, and cases where surgery occurred more than 24 hours after CT. A total of 164 patients met study criteria. Bowel ischaemia was confirmed based on surgical findings (e.g., bowel necrosis, loss of peristalsis, mucosal discoloration) or histopathological examination after bowel resection. In patients managed conservatively, ischaemia was ruled out if they recovered uneventfully over three months. CT scans were performed with standardized protocols, including unenhanced and contrast-enhanced imaging. Three radiologists independently reviewed the scans, blinded to clinical outcomes. They assessed the presence or absence of the three key findings from the Millet score, as well as increased unenhanced bowel-wall attenuation. Millet score was considered positive if at least 2 out of 3 signs were present. A Millet+ score, adding the increased unenhanced bowel-wall attenuation sign, was also tested and was considered positive if at least 2 out of the 4 signs were present. Among the 164 patients, 41 (25%) had ischaemic bowel-wall findings confirmed surgically, while 123 (75%) had no ischaemia (107 managed conservatively, 16 operated with no ischaemia detected). Millet score performed in line with the original study, showing high specificity (97%), with an AUROC of 0.87 and a NPV of 93%. Adding the increased unenhanced bowel-wall attenuation sign (Millet+ score) to the scoring system slightly improved classification but did not significantly enhance diagnostic accuracy. While unenhanced imaging has been highlighted in previous research for detecting hemorrhagic necrosis, its incremental value in this study was limited—possibly due to a small sample size or the fact that this finding appears later in ischaemic progression. The study also observed that a closed-loop mechanism alone is not a reliable predictor of ischaemia on CT, consistent with earlier reports, suggesting that conservative management is still possible in some cases. | Authors acknowledge some limitations beyond those already mentioned above, including: its retrospective design, which may have introduced selection bias; the assessment based on CT scan reviews rather than real-time emergency readings, potentially overestimating the score’s performance; the study also incorporated additional CT indicators to improve detection, such as C- or U-shaped configurations and radial loop distribution, into the definition of closed-loop SBO. In conclusion, this study successfully validates the Millet score for predicting bowel ischaemia in acute adhesive SBO patients. It confirmed that requiring at least two of the three key CT findings provided high specificity and a strong negative predictive value. The findings align with previous studies, reinforcing the score’s clinical utility as a reliable, simple and accurate tool for predicting bowel ischaemia in SBO, while not establishing a significant improvement in diagnostic performance by adding increased unenhanced bowel-wall attenuation to the score. Further research is needed to determine whether incorporating the Millet score into surgical decision-making improves patient outcomes.
Millet I, Boutot D, Faget C, et al. Assessment of Strangulation in Adhesive Small Bowel Obstruction on the Basis of Combined CT Findings: Implications for Clinical Care. Radiology. 2017;285(3):798-808. doi:10.1148/radiol.2017162352 Paulson EK, Thompson WM. Review of small-bowel obstruction: the diagnosis and when to worry. Radiology. 2015;275(2):332-342. doi:10.1148/radiol.15131519 Miller G, Boman J, Shrier I, et al. Etiology of small bowel obstruction. Am J Surg. 2000;180(1):33-36. doi:10.1016/s0002-9610(00)00407-4 Chuong AM, Corno L, Beaussier H, et al. Assessment of Bowel Wall Enhancement for the Diagnosis of Intestinal Ischemia in Patients with Small Bowel Obstruction: Value of Adding Unenhanced CT to Contrast-enhanced CT. Radiology. 2016;280(1):98-107. doi:10.1148/radiol.2016151029 Pedro Silva is a second-year radiology resident at “Unidade Local de Saúde do Alto Minho (ULSAM)” in Viana do Castelo, Portugal. He completed his undergraduate medical training at the Faculty of Medicine of the University of Porto. He has taken particularly interest in abdominal and cardiovascular radiology. Comments may be sent to: pedromasilva21@gmail.com |
February 2025
