Đặc điểm hình ảnh và giá trị của cắt lớp vi tính trong chẩn đoán tắc ruột quai đóng do dải xơ dính

Abstract

Objective: To describe computed tomography (CT) imaging features in patients with closed-loop bowel obstruction (CLBO) caused by adhesive bands and to determine the value of CT in diagnosing and predicting bowel ischemia/necrosis in patients with adhesive band-related closed-loop bowel obstruction.

Subjects and methods: This was a retrospective cross-sectional descriptive study collecting data from 200 patients diagnosed with bowel obstruction and surgically treated at Hanoi Medical University Hospital between July 2024 and December 2025.

Results: Among 200 surgically treated patients with bowel obstruction, 49 patients had CLBO (24.5%) and 151 patients had non–closed-loop bowel obstruction (75.5%). Among the 49 CLBO patients, 33 cases were caused by adhesive bands (67.3%), 12 cases by internal or external hernias (24.5%), and 4 cases by volvulus (8.2%).

On CT in 33 patients with adhesive band-related CLBO, the adhesive band sign showed a sensitivity of 12.1%, specificity of 100%, positive predictive value (PPV) of 100%, and negative predictive value (NPV) of 35.6%. Air–fluid levels, the beak sign, and the presence of at least two transition points demonstrated high sensitivities of 97%, 75.8%, and 93.9%, respectively, but low specificities of 6.3%, 31.3%, and 18.8%, respectively. U-/C-shaped bowel loops and the whirl sign had low sensitivities of 9.1% and 12.1%, respectively, but relatively high specificities of 68.8% for both. The radial distribution sign showed a relatively high PPV of 76%.

On CT in 33 patients with adhesive band-related CLBO, mesenteric edema/fat stranding and free intraperitoneal fluid both demonstrated sensitivities and NPVs of 100%. However, mesenteric edema/fat stranding showed relatively high specificity and PPV of 71.4% and 66.7%, respectively, whereas free intraperitoneal fluid demonstrated low specificity and PPV of 4.8% and 37.5%, respectively. Reduced bowel wall enhancement, reduced mesenteric vascular enhancement, and pneumatosis intestinalis/portal venous gas all demonstrated specificities and PPVs of 100%. Bowel wall thickening in dilated bowel loops and the target sign of bowel wall enhancement showed high specificity, PPV, and NPV, respectively: 95.2%, 88.9%, and 83.3% for bowel wall thickening in dilated bowel loops, and 95.2%, 80%, and 71.4% for the target sign.

Conclusion: Adhesive bands are the primary cause of closed-loop bowel obstruction. Diagnosis mainly relies on indirect signs such as the beak sign and radial distribution sign, whereas direct visualization of adhesive bands, although highly specific, remains difficult on CT. Reduced bowel wall enhancement, reduced mesenteric vascular enhancement, and pneumatosis intestinalis/portal venous gas are highly specific indicators of bowel ischemia/necrosis.