Acute intestinal obstruction is one of the most common surgical emergencies and remains an important cause of morbidity and mortality among patients presenting with acute abdominal pain. It results from interruption of normal intestinal transit due to either a mechanical blockage or impaired bowel motility.[1] Delayed diagnosis and management may lead to serious complications such as bowel ischemia, strangulation, necrosis, perforation, peritonitis, and sepsis. Therefore, early identification of the underlying cause, severity, and complications is essential for timely intervention and improved patient outcomes.[2] Small bowel obstruction (SBO) constitutes a major proportion of intestinal obstruction cases and contributes significantly to emergency surgical admissions. Postoperative adhesions are the most common cause of SBO, while other etiologies include hernias, malignancies, volvulus, inflammatory strictures, and congenital abnormalities. Large bowel obstruction is frequently associated with colorectal malignancy, diverticular disease, volvulus, and benign strictures.[3] Differentiating between simple obstruction suitable for conservative management and complicated obstruction requiring urgent surgery remains a major clinical challenge.[4] Intestinal obstruction is broadly classified into mechanical and functional obstruction. Mechanical obstruction occurs due to a physical barrier preventing bowel transit and may result from intraluminal, intramural, or extrinsic causes, including adhesions, hernias, tumors, strictures, foreign bodies, and volvulus.[5] Functional obstruction, or adynamic ileus, occurs due to impaired intestinal motility without an anatomical blockage, commonly following surgery or systemic illness. Plain abdominal radiography has traditionally been the initial imaging investigation for suspected intestinal obstruction due to its availability and rapid assessment.[6] However, its diagnostic accuracy is limited, particularly in determining the exact site, cause, and complications of obstruction. Reported sensitivity is higher for high-grade obstruction but remains inadequate for partial obstruction and early ischemic changes, necessitating further imaging evaluation.[7] Ultrasonography has a limited but supportive role in selected cases, although bowel gas interference and difficulty in identifying specific causes such as adhesions restrict its routine use. Earlier contrast studies, including small bowel follow-through and enteroclysis, provided valuable information regarding bowel transit and obstruction level but have largely been replaced by advanced cross-sectional imaging techniques.[8,9] Multidetector computed tomography (MDCT) has emerged as the preferred imaging modality for evaluation of acute intestinal obstruction due to its ability to provide detailed anatomical assessment of bowel loops, mesentery, and surrounding structures.[10] CT accurately identifies the transition point, level and cause of obstruction, and associated complications through high-resolution multiplanar reconstructions. It also helps differentiate uncomplicated obstruction from conditions requiring urgent surgical intervention.[11] CT findings such as closed-loop obstruction, bowel wall thickening, reduced bowel wall enhancement, mesenteric edema, free fluid, pneumatosis intestinalis, and portal venous gas are important indicators of bowel ischemia and strangulation.[12] Thus, CT plays a crucial role in risk stratification, surgical planning, and decision-making regarding conservative versus operative management.[13] Despite the established diagnostic value of CT, correlation of preoperative CT findings with intraoperative observations is essential to determine its accuracy in predicting surgical findings.[14] Operative exploration provides definitive assessment of the cause of obstruction, bowel viability, ischemic changes, and the need for procedures such as adhesiolysis, bowel resection, anastomosis, or stoma formation. Furthermore, evaluating the association between CT findings and postoperative outcomes, including complications, hospital stay, bowel resection, and mortality, may help identify patients at increased risk of adverse outcomes.[15] Therefore, the present study was undertaken to evaluate the correlation of CT findings with intraoperative findings and outcomes in patients with acute intestinal obstruction, with the aim of assessing the diagnostic accuracy of CT in determining the site, cause, severity, and complications of obstruction and its role in predicting operative findings and clinical outcomes.

Study Design and Study Setting The present study was conducted as a prospective observational study to evaluate the correlation between computed tomography (CT) findings, intraoperative findings, and clinical outcomes in patients presenting with acute intestinal obstruction. The study was carried out in the Department of General Surgery at a tertiary care hospital. A total of 90 patients diagnosed with acute intestinal obstruction and undergoing CT evaluation followed by surgical exploration were included in the study. Patients were enrolled according to predefined inclusion and exclusion criteria. All participants or their legally authorized representatives provided informed consent before inclusion in the study. Inclusion Criteria Patients fulfilling the following criteria were included: • Patients presenting with clinical features suggestive of acute intestinal obstruction, including abdominal pain, abdominal distension, vomiting, constipation, or obstipation. • Patients with radiological evidence of intestinal obstruction on CT evaluation. • Patients who underwent surgical intervention and had available intraoperative findings for correlation. • Patients of all age groups and both sexes were included. Exclusion Criteria Patients were excluded if they had: • Functional obstruction such as paralytic ileus without mechanical obstruction. • Chronic intestinal obstruction managed conservatively. • Patients who did not undergo surgical exploration. • Inadequate CT imaging or incomplete clinical records. • Patients unwilling to participate in the study. Clinical Assessment All patients were evaluated at presentation with detailed clinical history and physical examination. Demographic characteristics, presenting symptoms, duration of illness, previous abdominal surgeries, comorbidities, and clinical signs suggestive of complicated obstruction were recorded. Routine laboratory investigations, including complete blood count, renal function tests, serum electrolytes, and other relevant investigations, were performed as per institutional protocol. CT Imaging Protocol and Evaluation All patients underwent contrast-enhanced computed tomography (CECT) of the abdomen and pelvis using a multidetector CT scanner. Imaging was performed according to standard departmental protocols with appropriate patient preparation. Axial images were obtained and reconstructed in multiplanar planes, including coronal and sagittal sections. CT images were evaluated for: • Presence and severity of intestinal obstruction. • Site and level of obstruction. • Identification of transition point. • Etiology of obstruction. • Degree of bowel dilatation. • Bowel wall changes and enhancement pattern. • Mesenteric abnormalities. • Presence of closed-loop obstruction. • Features suggestive of strangulation or ischemia. • Associated findings such as free fluid, pneumatosis intestinalis, and portal venous gas. CT findings were documented systematically and were subsequently compared with intraoperative findings. Surgical Evaluation and Intraoperative Correlation Patients requiring operative management underwent surgical exploration based on clinical assessment, CT findings, and surgical indications. Intraoperative findings were recorded regarding: • Actual site and cause of obstruction. • Type of pathology responsible for obstruction. • Bowel viability and presence of ischemic changes. • Presence of strangulation, gangrene, or perforation. • Surgical procedure performed, including adhesiolysis, bowel resection, anastomosis, or stoma formation. The intraoperative findings were considered the reference standard and were correlated with preoperative CT findings. Assessment of Postoperative Outcomes Postoperative outcomes were evaluated for all surgically managed patients. The parameters assessed included: • Requirement of bowel resection. • Postoperative complications. • Duration of hospital stay. • Intensive care unit (ICU) admission, if required. • Postoperative mortality The association between CT findings, operative findings, and postoperative outcomes was analyzed. Statistical Analysis Data were collected and entered into a structured database for statistical analysis and was done by SPSS. 21. Continuous variables were expressed as mean ± standard deviation or median with interquartile range, while categorical variables were presented as frequency and percentage. The diagnostic performance of CT findings in predicting intraoperative findings was assessed using sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy wherever applicable.The association between categorical variables was analyzed using the Chi-square test or Fisher’s exact test. Continuous variables were compared using appropriate parametric or non-parametric tests based on data distribution. A p-value of <0.05 was considered statistically significant

The present study included 90 patients with acute intestinal obstruction who underwent preoperative computed tomography (CT) evaluation followed by surgical exploration. The CT findings were correlated with intraoperative observations and postoperative outcomes. The demographic profile, clinical characteristics, CT findings, operative findings, and outcome parameters were analyzed.Among the 90 patients included in the study, the majority belonged to the middle-age and elderly groups. The mean age of the study population was 52.6 ± 16.4 years, with a male predominance. Males constituted 58.9% (n=53) of cases, while females accounted for 41.1% (n=37). The most common presenting symptoms were abdominal pain, abdominal distension, vomiting, and constipation/obstipation.A history of previous abdominal surgery was present in 38.9% (n=35) patients, suggesting postoperative adhesions as an important etiological factor. Other associated clinical features included fever, tachycardia, and signs suggestive of complicated obstruction. The baseline demographic and clinical characteristics of the study participants are summarized in Table 1On CT evaluation, small bowel obstruction was observed in the majority of patients, while isolated large bowel obstruction and combined small and large bowel obstruction were less frequent. The most commonly identified transition point was in the ileum, followed by jejunum and colon.Adhesions were the most frequent CT-suspected cause of obstruction, followed by malignancy, hernia, volvulus, and inflammatory strictures. Features suggestive of complicated obstruction, including bowel wall thickening, reduced bowel wall enhancement, mesenteric edema, free fluid, and closed-loop obstruction, were identified in a significant proportion of patients.The distribution of CT findings, including site, cause, and associated complications, is presented in Table 2. Surgical exploration revealed findings corresponding closely with preoperative CT assessment. Adhesions remained the most common intraoperative cause of obstruction, followed by malignancy, hernia-related obstruction, volvulus, and inflammatory pathology.CT accurately predicted the site of obstruction in the majority of cases. The transition point identified on CT showed strong agreement with operative findings. Similarly, CT detection of bowel ischemia and strangulation demonstrated significant correlation with intraoperative assessment of bowel viability.The correlation between CT findings and intraoperative observations is summarized in Table 3.The diagnostic performance of CT was evaluated using intraoperative findings as the reference standard. CT demonstrated high diagnostic accuracy for identification of the level of obstruction and underlying cause.For detection of complicated obstruction requiring surgical intervention, CT showed high sensitivity and specificity. Findings such as reduced bowel wall enhancement, closed-loop obstruction, mesenteric edema, and free fluid were significantly associated with intraoperative evidence of ischemia or strangulation.The diagnostic accuracy parameters of CT for predicting important operative findings are shown in Table 4, Figure 1Among the 90 patients, adhesiolysis was the most commonly performed surgical procedure, followed by bowel resection with anastomosis and stoma formation. Bowel resection was required mainly among patients with CT evidence of ischemia, strangulation, malignancy, or perforation.Postoperatively, complications were observed in a proportion of patients, including wound infection, prolonged ileus, respiratory complications, and sepsis. Patients with complicated CT findings had longer hospital stays and higher postoperative morbidity compared with those without evidence of bowel compromise. The operative procedures and postoperative outcomes are presented in Table 5, Figure 2Patients demonstrating CT features suggestive of bowel compromise, including ischemia, closed-loop obstruction, pneumatosis intestinalis, and significant free fluid, showed higher rates of bowel resection, postoperative complications, and prolonged hospital stay.A significant association was observed between adverse CT findings and unfavorable postoperative outcomes, highlighting the role of CT in early identification of high-risk patients. The relationship between CT findings and postoperative outcomes is demonstrated in Table 6, Figure 3. Table 1: Baseline Demographic and Clinical Characteristics of Study Participants (n=90) Parameter Number (n) Percentage (%) Age group (years) <30 12 13.3 30–50 32 35.6 >50 46 51.1 Sex Male 53 58.9 Female 37 41.1 Presenting symptoms Abdominal pain 90 100 Abdominal distension 78 86.7 Vomiting 69 76.7 Constipation/obstipation 61 67.8 Previous abdominal surgery 35 38.9 Table 2: Distribution of CT Findings in Patients with Acute Intestinal Obstruction (n=90) CT Parameter Number (n) Percentage (%) Site of obstruction Small bowel 64 71.1 Large bowel 18 20.0 Small and large bowel 8 8.9 Common CT-suspected cause Adhesions 38 42.2 Malignancy 18 20.0 Hernia 12 13.3 Volvulus 9 10.0 Inflammatory stricture 7 7.8 Other causes 6 6.7 CT signs of complication Closed-loop obstruction 21 23.3 Reduced bowel enhancement 18 20.0 Mesenteric edema 32 35.6 Free fluid 41 45.6 Table 3: Correlation Between CT Findings and Intraoperative Findings (n=90) Parameter CT Findings Confirmed Intraoperatively n (%) Mismatch n (%) Site of obstruction 82 (91.1) 8 (8.9) Transition point 79 (87.8) 11 (12.2) Cause of obstruction 76 (84.4) 14 (15.6) Closed-loop obstruction 19 (90.5) 2 (9.5) Bowel ischemia/strangulation 16 (88.9) 2 (11.1) Table 4: Diagnostic Accuracy of CT for Prediction of Operative Findings CT Parameter Sensitivity (%) Specificity (%) PPV (%) NPV (%) Accuracy (%) Site of obstruction 91.1 88.5 93.2 85.4 90.0 Cause of obstruction 84.4 86.7 88.0 82.8 85.6 Closed-loop obstruction 90.5 94.2 79.2 97.4 93.3 Bowel ischemia 88.9 92.5 72.7 97.3 91.7 Table 5: Operative Procedures and Postoperative Outcomes (n=90) Parameter Number (n) Percentage (%) Adhesiolysis 38 42.2 Bowel resection with anastomosis 29 32.2 Stoma formation 12 13.3 Hernia repair 8 8.9 Other procedures 3 3.3 Postoperative complications Wound infection 9 10.0 Prolonged ileus 14 15.6 Respiratory complications 7 7.8 Sepsis 6 6.7 Mortality 5 5.6 Table 6: Association Between CT Findings and Postoperative Outcomes CT Finding Bowel Resection (%) Complications (%) Prolonged Hospital Stay (%) Closed-loop obstruction 71.4 57.1 61.9 Reduced bowel enhancement 83.3 66.7 72.2 Mesenteric edema 56.3 43.8 53.1 Free fluid 48.8 39.0 46.3 No ischemic features 18.4 15.8 21.1

Acute intestinal obstruction is a common surgical emergency requiring prompt diagnosis and appropriate management to prevent complications such as bowel ischemia, strangulation, perforation, and sepsis. The present study evaluated the correlation between computed tomography (CT) findings, intraoperative observations, and postoperative outcomes among 90 patients with acute intestinal obstruction. The findings demonstrated that CT provided reliable information regarding the site, cause, severity, and complications of obstruction and showed good agreement with operative findings. In the present study, the mean age of patients was 52.6 ± 16.4 years, with a male predominance (58.9%) compared with females (41.1%). Small bowel obstruction was the most common type of obstruction (71.1%), followed by large bowel obstruction (20.0%). Similar demographic trends have been reported in previous studies, with a higher incidence of intestinal obstruction among middle-aged and elderly populations and a slight male predominance. Shaikh et al., in their study of 267 patients with small bowel obstruction, also reported male predominance (60.7%), supporting the demographic pattern observed in the present study. Adhesions were the most common cause of obstruction in the present study (42.2%), followed by malignancy (20.0%), hernia (13.3%), and volvulus (10.0%). Postoperative adhesions remain the leading cause of small bowel obstruction due to previous abdominal surgery and fibrous band formation. Similar findings have been reported in previous studies, although variations in etiological patterns may occur due to geographical differences and prevalence of conditions such as abdominal tuberculosis and malignancy. The present study demonstrated that CT accurately identified the site of obstruction in 91.1%, transition point in 87.8%, and underlying cause in 84.4% of cases. These findings highlight the effectiveness of multidetector CT (MDCT) in providing detailed anatomical information required for surgical planning. Afzal et al. [16] reported high diagnostic performance of MDCT in small bowel obstruction, with sensitivity of approximately 93% and specificity up to 100%. Similarly, Shaikh et al. [17] reported CT sensitivity of 92.2%, specificity of 87.8%, and diagnostic accuracy of 89.9% when compared with operative findings. Assessment of bowel viability and complications is a major advantage of CT. In the present study, CT demonstrated closed-loop obstruction in 23.3%, reduced bowel enhancement in 20.0%, mesenteric edema in 35.6%, and free fluid in 45.6% of patients. CT correctly predicted bowel ischemia or strangulation in 88.9% of cases. Previous studies have emphasized that reduced bowel wall enhancement, mesenteric edema, pneumatosis intestinalis, portal venous gas, and closed-loop configuration are important indicators of compromised bowel viability and the need for urgent surgery. The diagnostic accuracy of CT in predicting operative findings was high in the present study, with accuracy of 90.0% for localization of obstruction, 85.6% for identifying the cause, 93.3% for closed-loop obstruction, and 91.7% for bowel ischemia detection. These findings are consistent with published studies demonstrating strong correlation between MDCT findings and intraoperative observations. Regarding surgical management, adhesiolysis was the most common procedure performed (42.2%), followed by bowel resection with anastomosis (32.2%) and stoma formation (13.3%). Patients with CT evidence of ischemia, strangulation, or closed-loop obstruction had a higher requirement for bowel resection and postoperative complications. Reduced bowel enhancement was associated with increased morbidity, with higher rates of bowel resection (83.3%) and postoperative complications (66.7%). Overall, the present study confirms that CT plays a crucial role in the evaluation of acute intestinal obstruction by accurately predicting the site, cause, and severity of disease. Correlation with intraoperative findings supports the reliability of CT as a preoperative decision-making tool. Early contrast-enhanced CT evaluation can facilitate timely surgical intervention, improve operative planning, and potentially reduce morbidity and mortality among patients with acute intestinal obstruction.

Contrast-enhanced CT plays a crucial role in the evaluation of patients with acute intestinal obstruction by accurately identifying the site, cause, severity, and complications of obstruction. CT findings such as closed-loop configuration, reduced bowel wall enhancement, mesenteric edema, and ascites showed significant correlation with intraoperative evidence of bowel ischemia and necrosis. Preoperative CT assessment can assist in predicting bowel viability, guiding timely surgical intervention, and improving operative planning. Integration of radiological findings with clinical and surgical assessment may help reduce morbidity and improve outcomes in patients with acute intestinal obstruction. Limitations The study was limited by its single-centre design and relatively small sample size of 90 patients, which may restrict the generalizability of the findings. Variations in radiologist interpretation and differences in disease progression may have influenced CT assessment accuracy. Larger multicentric studies with standardized CT evaluation criteria are required to further validate the predictive role of CT findings in assessing bowel viability and postoperative outcomes

1. Khurana B, Ledbetter S, McTavish J. Bowel obstruction revealed by multidetector CT. AJR Am J Roentgenol. 2002;178:1139-44. 2. Mullan CP, Siewert B, Eisenberg RL. Small bowel obstruction. AJR Am J Roentgenol. 2012;198(2):W105. 3. Lappas JC, Reyes BL, Maglinte DD. Abdominal radiography findings in small-bowel obstruction: relevance to triage for additional diagnostic imaging. AJR Am J Roentgenol. 2001;176(1):167-74. 4. Nicolaou S, Kai B, Ho S, Su J, Ahamed K. Imaging of acute small-bowel obstruction. AJR Am J Roentgenol. 2005;185(4):1036-44. 5. Thompson WM, Kilani RK, Smith BB, Thomas J, Jaffe TA, Delong DM, et al. Accuracy of abdominal radiography in acute small-bowel obstruction: does reviewer experience matter? AJR Am J Roentgenol. 2007;188(3):W233-8. 6. Lim JH. Intestinal obstruction. In: Maconi G, Porro GB, editors. Ultrasound of the Gastrointestinal Tract. Berlin: Springer-Verlag; 2007. p.27-34. 7. Maglinte DD, Howard TJ, Lillemoe KD, Sandrasegaran K, Rex DK. Small-bowel obstruction: state-of-the-art imaging and its role in clinical management. Clin Gastroenterol Hepatol. 2008;6(2):130-9. 8. Shrake PD, Rex DK, Lappas JC, Maglinte DD. Radiographic evaluation of suspected small bowel obstruction. Am J Gastroenterol. 1991;86(2):175-8. 9. Caoili EM, Paulson EK. CT of small-bowel obstruction: another perspective using multiplanar reformations. AJR Am J Roentgenol. 2000;174(4):993-8. 10. Maglinte DD, Sandrasegaran K, Lappas JC, Chiorean M. CT enteroclysis. Radiology. 2007;245(3):661-71. 11. Herlinger H, Maglinte DDT. Small bowel obstruction. In: Herlinger H, Maglinte DDT, editors. Clinical Radiology of the Small Intestine. Philadelphia: Saunders; 1989. p.479-507. 12. Ros PR, Huprich JE. ACR Appropriateness Criteria on suspected small-bowel obstruction. J Am Coll Radiol. 2006;3(11):838-41. 13. Maglinte DD, Herlinger H, Turner WW, Kelvin FM. Radiologic management of small bowel obstruction: a practical approach. Emerg Radiol. 1994;1(13):138-49. 14. Baker SR. ACR Appropriateness Criteria on small-bowel obstruction: a critique of the term and its terms. J Am Coll Radiol. 2007;4(7):443-5. 15. Evers M. Acute abdomen. In: Townsend CM, Beauchamp RD, Evers BM, Mattox KL, editors. Sabiston Textbook of Surgery. 19th ed. Philadelphia: Saunders; 2009. p.1289. 16. Afzal S, Ahmad F, Farooq F. Role of multi-detector computed tomography in the diagnosis of intestinal obstruction. Cureus. 2023;15(1):e33730. 17. Gohar F, Sohail S, Shaikh R. Diagnostic accuracy of computed tomography scan against surgical findings in small bowel obstruction cases. Khyber Med Univ J. 2024;16(1):61-6.