Closed-Loop Small-Bowel Obstruction

Value of dual-energy computed tomography in the diagnosis of bowel ischemia in patients with mechanical small-bowel obstruction: a retrospective, dual-center study

OBJECTIVES

To investigate the diagnostic value of rapid-kV-switching dual-energy CT (DECT) for identifying bowel ischemia in patients with mechanical small-bowel obstruction (SBO), compared to 120 kVp-equivalent CT.

MATERIALS AND METHODS

This retrospective dual-center study included 112 patients with mechanical SBO. Clinical and surgical outcomes with histological findings were recorded as the reference standard. Three readers independently reviewed true unenhanced (TUE) and portal-venous 77-keV virtual monoenergetic images (VMI) (dataset#1), virtual unenhanced (VUE), iodine, and 50-keV VMI (dataset#2). Ischemia was defined as the presence of at least two CT features among reduced bowel-wall enhancement, diffuse mesenteric haziness, and a closed-loop mechanism. Unenhanced bowel-wall attenuation was also analysed. Bowel-wall attenuation and iodine concentration were measured in involved loops and proximal dilated loops. Sensitivity and specificity were calculated for each CT feature. Association between iodine concentration and bowel ischemia was analysed using ROC curves.

RESULTS

Forty-one (37%) patients underwent surgery. Twenty-four (21%) patients had findings of bowel ischemia, including 11 (10%) patients with irreversible ischemia (necrosis). Diagnostic performance for ischemia and necrosis was similar between both datasets for all readers (p > 0.49 for ischemia and p = 1 for necrosis). Increased bowel-wall attenuation on VUE or TUE images had a non-significantly different diagnostic value for all readers (p > 0.21 for ischemia and p > 0.78 for necrosis). Bowel-wall iodine concentration identified bowel necrosis with 82% sensitivity and 83% specificity (optimal cutoff value 1.82 mg/mL).

CONCLUSION

DECT performed similarly to 120 kVp-equivalent CT for the diagnosis of bowel ischemia in patients with mechanical SBO. VUE images offer a viable alternative to TUE images for the identification of increased bowel-wall attenuation. Bowel-wall iodine concentration accurately identifies bowel necrosis.

KEY POINTS

Question Dual-energy CT (DECT) could detect small-bowel ischemia caused by mechanical small-bowel obstruction (SBO), but its performance is unknown. Findings Reduced bowel-wall enhancement and increased unenhanced bowel-wall attenuation were not significantly different between DECT and 120 kVp-equivalent CT. Bowel-wall iodine concentration identified necrosis with 82% sensitivity and 83% specificity. Clinical relevance DECT performed similarly to 120 kVp-equivalent CT in depicting bowel ischemia in patients with mechanical SBO, while adding quantitative analysis of bowel-wall iodine concentration may further help identify patients requiring 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.

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.

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 role of computed tomography in acute bowel obstruction due to a supravesical hernia: a case report from Nepal

Introduction and importance

Supravesical hernias are rare internal hernias but potential cause of small-bowel obstruction. The clinical features are often non-specific, preoperative diagnosis is very difficult and is often diagnosed intraoperatively. The exact pathogenesis is unclear with the major risk factors of prematurity, a positive family history, male sex, smoking habits leading to decreased collagen production, advancing age, and conditions characterized by defective collagen synthesis.

Case presentation

The authors are reporting a case of small-bowel obstruction secondary to a supravesical hernia, in a 78-year-old male presented with central abdominal pain, vomiting and obstipation. Ultrasonography of the abdomen and pelvis identified a marked dilation of the small-bowel loop with multiple loops of dilated jejunum and ileum in contrast-enhanced computed tomography (CT) scan of the abdomen and pelvis with lead point from the terminal ileum. Exploratory laparotomy was done with the diagnosis of left posterior a left posterior superior vesical hernia with small-bowel obstruction.

Clinical discussion

The case focuses supravesical hernia as a rare yet life-threatening etiology of small-bowel obstruction, emphasizing the importance of clinical suspicion when patients present with signs and symptoms of bowel obstruction. While diagnosis often occurs intraoperatively, the utilization of CT scans in emergency settings can provide valuable insights into the location, potential causes, and condition of the herniated bowel sac. The case highlights the pivotal role of CT scans in diagnosis and emphasizes the need for multidisciplinary cooperation among clinicians, radiologists, and surgeons.

Conclusion

Early intervention ensures better outcomes and prevents irreversible bowel damage, underscoring the importance of a comprehensive approach to patient care.

Unusual Triggers of Acute Intestinal Obstruction in Surgical Emergencies: A Series of Five Cases

Intestinal obstruction is a common surgical emergency that can be caused by mechanical causes or by different pathological processes. The most common cause of small bowel intestinal obstruction is post-operative adhesion, and the most common cause of large bowel obstruction is malignancy. These are classified into dynamic and adynamic types. The patient was selected based on the presentation management plan. Some cases require immediate operative intervention; however, some cases, as mentioned in this case series, require further investigation and a different approach. In this study, we report the rare causes of intestinal obstruction presented to Safdarjung Hospital, Department of General Surgery, New Delhi: one case of foreign body impaction, one case of spontaneous migration of feeding jejunostomy, one case of extrauterine IUCD causing intestinal obstruction, one case of mesentery band causing obstruction, and one case of abdominopelvic mass causing small bowel obstruction. These cases presented to the surgical emergency department with challenges in their diagnosis, intraoperative findings, and their outcomes.

Prediction of bowel necrosis by reduced bowel wall enhancement in closed-loop small bowel obstruction: Quantitative methods

PURPOSE

To assess diagnostic performance and reproducibility of reduced bowel wall enhancement evaluated by quantitative methods using CT to identify bowel necrosis among closed-loop small bowel obstruction (CL-SBO) patients.

METHODS

This retrospective single-center study included patients who diagnosed with CL-SBO caused by adhesion or internal hernia during January 2016 and May 2022. Patients were divided into necrotic group (n = 41) and non-necrotic group (n = 67) according to surgical exploration and postoperative pathology. Two doctors independently measured the attenuation of bowel wall and consensus was reached through panel discussion with a third gastrointestinal radiologist. Reduced bowel wall enhancement was assessed by four quantitative methods. Univariate analyses were used to evaluate the association between each method and bowel necrosis, and kappa/intraclass correlation coefficient values were used to assess interobserver agreement. Diagnostic performance parameters were calculated for each method.

RESULTS

Reduced bowel wall enhancement in arterial phase (OR 8.98, P < 0.0001), reduced bowel wall enhancement in portal phase (OR 16.84, P < 0.001), adjusted reduced bowel wall enhancement in arterial phase (OR 29.48, P < 0.001), adjusted reduced bowel wall enhancement in portal phase (OR 145.69, P < 0.001) were significantly associated with bowel necrosis. Adjusted reduced bowel wall enhancement in portal phase had the best diagnostic performance (AUC: 0.92; Youden index: 0.84; specificity: 94.03 %) and interobserver agreement (kappa value of 0.59-0.73) to predict bowel necrosis.

CONCLUSION

When assessing reduced bowel enhancement to predict bowel necrosis among CL-SBO patients, using unenhanced CT images and proximal dilated loop as standard references in portal phase is the most accurate quantitative method among those tested.

Persistent Vitello-Intestinal Duct Masquerading as Acute Appendicitis: A Case Report

The vitello-intestinal duct normally regresses with the development. But, in certain cases, it could persist and present as Meckel's diverticulum. Here we report a case of an eight-year-old boy presenting with peri-umbilical abdominal pain, vomiting and loose stool. He was initially diagnosed and managed as acute appendicitis but did not improve, rather developed features of intestinal obstruction. Exploratory laparotomy was done which revealed persistent vitello-intestinal duct and was managed surgically. This case report highlights that in any case of suspected acute appendicitis, the complications of persistent vitello-intestinal duct should be considered as one of the differentials.

Keywords

appendicitis; case reports; intestinal obstruction; laparotomy; omphalomesenteric duct.

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.

Closed loop obstruction of small bowel: CT signs predicting successful non-surgical treatment

PURPOSE

To clarify the computed tomography (CT) findings related to successful conservative treatments in patients with closed-loop small bowel obstruction (CL-SBO) without evidence of bowel strangulation.

METHODS

Sixty-four patients (71 CT scans) diagnosed with CL-SBO by CT and received initial conservative treatments from May 2010 to August 2020 were retrospectively included. Two blinded radiologists reviewed the CT findings, including the transition zone (number, distance, and location), maximum bowel diameter, mesenteric haziness, mesenteric fluid, increased unenhanced bowel wall attenuation, decreased bowel wall enhancement, small bowel feces sign, whirl sign, bowel wall thickening, ascites, and degree of obstruction. The findings of the success and failure groups of conservative treatment were compared. Interobserver agreement was assessed for all findings.

RESULTS

Among the 71 cases, conservative treatments were successful in 42 cases (59 %) but failed in 29 cases (41 %). In multivariable analyses, the distance between the transition zones (>1 cm) and low-degree obstruction were independently associated with successful conservative treatments, with odds ratios of 6.23 and 3.52, respectively. The combination of these two CT findings exhibited a specificity of 89.7 % with a positive likelihood ratio of 3.01. Interobserver agreement of the degree of obstruction and the distance between the transition zones was almost perfect (ĸ = 0.814 and 0.914, respectively).

CONCLUSIONS

The distance between the transition zones (>1 cm) and low-grade obstruction are independent CT predictors of successful conservative treatments in CL-SBO patients. Initial conservative treatments are recommended for patients with both CT findings.

Imaging Signs for Determining Surgery Timing of Acute Intestinal Obstruction

We aimed to analyze the computed tomography (CT) imaging signs of bowel wall ischemia in patients with acute intestinal obstruction and construct an imaging prediction model to guide clinical treatment. The CT imaging signs of patients with acute intestinal obstruction diagnosed in our center in recent 6 years were collected for retrospective analysis. The etiology of intestinal obstruction and incidence rate of bowel wall ischemia were recorded, and the specific CT findings of bowel wall ischemia, including mesenteric edema, bowel wall thickening, and fish tooth sign, were analyzed. Among the 302 patients selected, 130 surgically treated patients were eligible for analysis. Bowel wall ischemia in acute intestinal obstruction showed an incidence rate of 14.90%, and the incidence rates of bowel wall ischemia in intra-abdominal hernia, intussusception, incarcerated external abdominal hernia, and volvulus were about 92.30%, 50%, 35.71%, 33.33%, and 12.59%, respectively. The incidence rate of bowel wall ischemia in simple adhesive intestinal obstruction was about 12.59%, and that in malignancy-induced intestinal obstruction was about 6.56%. Univariate analysis revealed 5 factors with statistical significance, including bowel wall thickening, mesenteric edema, bowel wall pneumatosis, ascites, and fish tooth sign. Multivariate logistic regression analysis indicated that fish tooth sign, bowel wall thickening, and mesenteric edema were able to predict bowel wall ischemia, and the corresponding partial regression coefficients were 2.164, 1.129, and 1.173, odds ratios (ORs) were 8.707, 3.093, and 3.232, sensitivity was 0.356, 0.400, and 0.844, and specificity was 0.859, 0.835, and 0.529, respectively. Imaging signs of bowel wall thickening, mesenteric edema, and fish tooth sign are valuable in predicting bowel wall ischemia, among which bowel wall thickening and mesenteric edema have relatively high specificity and fish tooth sign has a relatively high sensitivity. Furthermore, a fish tooth sign has the most favorable predictive value for bowel wall ischemia in acute intestinal obstruction, followed by bowel wall thickening and mesenteric edema.

Closed-bowel Loop Obstruction-An Unusual and Forgotten Complication of Feeding Jejunostomy: Case Report

Feeding jejunostomy (FJ) is done as a part of significant upper gastrointestinal surgical procedures for patients who cannot tolerate enteral feeds. This procedure is related to different mechanical, infective, and metabolic inconveniences. However, closed-bowel loop obstruction following FJ is rare. We report an unusual complication of closed-bowel loop obstruction in the postoperative period of FJ done for a locally advanced carcinoma of gastroesophageal (GE) junction for enteral access in a 67-year-old male patient. This patient required an emergency laparotomy, to forestall exacerbating of abdomen distension which could have led to gastric ischemia and perforation following obstruction. A redo FJ was done, and the patient had an uneventful postoperative recovery. Therefore, surgeons should have high clinical suspicion for a rarer complication like a closed-loop obstruction in a patient with upper abdominal pain and distension without vomiting following FJ.

How to cite this article

Balamurugan S, Aslam MM, Kadambari D, et al. Closed-bowel Loop Obstruction-An Unusual and Forgotten Complication of Feeding Jejunostomy: Case Report. Euroasian J Hepato-Gastroenterol 2022;12(2):92-94.

Acute abdomen in a known case of sigmoid cancer and review of Laplace Law: a case report

In this case, we discuss a case of young female patient was admitted with acute abdomen after a week since the diagnosis of a metastatic colon cancer. The case prompts the revision of Laplace Law, which can be grossly proven on the specimen shown below. The patient presented with a peculiar nontender distended acute abdomen, which further explains the pathophysiology of perforation and peritonitis. This case also produces evidence of colorectal cancer present in the younger population allowing more room for investigating other factors causing it.

Machine Learning Based Prediction Model for Closed-Loop Small Bowel Obstruction Using Computed Tomography and Clinical Findings

PURPOSE

The aim of the study was to develop a prediction model for closed-loop small bowel obstruction integrating computed tomography (CT) and clinical findings.

METHODS

The radiology database and surgical reports from 2 suburban teaching hospitals were retrospectively reviewed for patients undergoing surgery for suspected closed-loop small bowel obstruction (CLSBO). Two observers independently reviewed the CT scans for the presence of imaging features of CLSBO, blinded to the surgically confirmed diagnosis and clinical parameters. Random forest analysis was used to train and validate a prediction model for CLSBO, by combining CT and clinical findings, after randomly splitting the sample into 80% training and 20% test subsets.

RESULTS

Surgery confirmed CLSBO in 185 of 223 patients with clinically suspected CLSBO. Age greater than 52 years showed 2.82 (95% confidence interval = 1.13-4.77) times higher risk for CLSBO (P = 0.021). Sensitivity/specificity of CT findings included proximal dilatation (97/5%), distal collapse (96/2%), mesenteric edema (94/5%), pneumatosis (1/100%), free air (1/98%), and portal venous gas (0/100%). The random forest model combining imaging/clinical findings yielded an area under receiver operating curve of 0.73 (95% confidence interval = 0.58-0.94), sensitivity of 0.72 (0.55-0.85), specificity of 0.8 (0.28-0.99), and accuracy of 0.73 (0.57-0.85). Prior surgery, age, lactate, whirl sign, U/C-shaped bowel configuration, and fecalization were the most important variables in predicting CLSBO.

CONCLUSIONS

A random forest model found clinical factors including prior surgery, age, lactate, and imaging factors including whirl sign, fecalization, and U/C-shaped bowel configuration are helpful in improving the prediction of CLSBO. Individual CT findings in CLSBO had either high sensitivity or specificity, suggesting that accurate diagnosis requires systematic assessment of all CT signs.

Closed-Loop Bowel Obstruction Years After an Open Abdominal Aortic Aneurysm Repair

A 68-year-old male has a significant past medical history of severe aortic stenosis, peripheral arterial disease, chronic kidney disease, and an abdominal aortic aneurysm treated with a bifurcated interposition aortobiiliac graft. He was admitted to the hospital for an elective one-vessel coronary artery bypass graft and placement of a bioprosthetic aortic valve. Postoperatively, he developed worsening abdominal pain, leukocytosis, and inability to tolerate nutrition by mouth. Computed tomography revealed moderately dilated loops of the small bowel with two transition points in the right lower quadrant. He was taken emergently to the operating room for an exploratory laparotomy, and a 28-cm necrotic jejunal loop was entrapped posterior to the right iliac segment of the graft. In a patient with an intra-abdominal synthetic vascular graft, a closed-loop bowel obstruction caused by entrapment by the vascular graft is exceptionally rare; however, it should be considered in the presence of bowel obstruction.

ACR Appropriateness Criteria® Suspected Small-Bowel Obstruction

Small-bowel obstruction is a common cause of abdominal pain and accounts for a significant proportion of hospital admissions. Radiologic imaging plays the key role in the diagnosis and management of small-bowel obstruction as neither patient presentation, the clinical examination, nor laboratory testing are sufficiently sensitive or specific enough to diagnose or guide management. This document focuses on the imaging evaluation of the two most commonly encountered clinical scenarios related to small-bowel obstruction: the acute presentation and the more indolent, low-grade, or intermittent presentation. This document hopes to clarify the appropriate utilization of the many imaging procedures that are available and commonly employed in these clinical settings. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

A Systematic Review of the Clinical Presentation, Diagnosis, and Treatment of Small Bowel Obstruction

PURPOSE OF REVIEW

This study aimed to systematically review small bowel obstruction (SBO), focusing on recent changes in diagnosis/therapy.

RECENT FINDINGS

SBO incidence is about 350,000/annum in the USA. Etiologies include adhesions (65%), hernias (10%), neoplasms (5%), Crohn's disease (5%), and other (15%). Bowel dilatation occurs proximal to obstruction primarily from swallowed air and secondarily from intraluminal fluid accumulation. Dilatation increases mural tension, decreases mucosal perfusion, causes bacterial proliferation, and decreases mural tensile strength that increases bowel perforation risks. Classical clinical tetrad is abdominal pain, nausea and emesis, abdominal distention, and constipation-to-obstipation. Physical exam may reveal restlessness, acute illness, and signs of dehydration and sepsis, including tachycardia, pyrexia, dry mucous membranes, hypotension/orthostasis, abdominal distention, and hypoactive bowel sounds. Severe direct tenderness, involuntary guarding, abdominal rigidity, and rebound tenderness suggest advanced SBO, as do marked leukocytosis, neutrophilia, bandemia, and lactic acidosis. Differential diagnosis includes postoperative ileus, narcotic bowel, colonic pseudo-obstruction, mesenteric ischemia, and large bowel obstruction. Medical resuscitation includes intravenous hydration, correcting electrolyte abnormalities, intravenous antibiotics, nil per os, and nasoenteral suction. Abdominal CT with oral and intravenous gastrografin contrast is highly sensitive and specific in detecting/characterizing SBO. SBO usually resolves with medical therapy but requires surgery, preferentially by laparoscopy, for unremitting total obstruction, bowel perforation, severe ischemia, or clinical deterioration with medical therapy. Overall mortality is 10% but increases to 30% with bowel necrosis/perforation. Key point in SBO is early diagnosis, emphasizing abdominal CT; aggressive medical therapy including rehydration, antibiotics, and nil per os; and surgery for failed medical therapy.

Diagnostic performance of MDCT in identifying closed loop small bowel obstruction

PURPOSE

To assess the diagnostic performance of MDCT in the diagnosis of closed loop small bowel obstruction.

MATERIALS AND METHODS

One hundred fifty patients with CT reports including "small bowel obstruction (SBO)" between 1/30/2011 and 12/4/2012 were included (65 men, 85 women, mean age 63 years). CT examinations were independently and blindly reviewed by five radiologists to determine the presence of closed loop obstruction (CL-SBO) and to assess findings of bowel ischemia. Clinical records were reviewed to determine management and operative findings. Using operative findings as a gold standard, reader agreement for the diagnosis of and the CT findings associated with CLO was analyzed using Pearson's correlation (r). Positive predictive value (PPV) and negative predictive value for the diagnosis of CL-SBO and CT signs of bowel ischemia were analyzed.

RESULTS

Eighty-eight of 150 patients underwent operative intervention for SBO and 24/88 were considered CL-SBO operatively. Average reader sensitivity and specificity for CL-SBO was 53 % (95 % CI 44-63 %) and 83 % (95 % CI 79-87 %). Reader agreement on CL-SBO was poor to moderate (K = 0.39-0.63). Reader agreement for CT signs of bowel ischemia resulting in a diagnosis of CL-SBO was weak (r = 0.19-0.32).

CONCLUSION

The CT diagnosis of CL-SBO is complex and associated imaging findings have variable sensitivity for predicting a closed loop operative diagnosis. CT can be helpful in excluding a closed loop component in patients with SBO.

Imaging the postoperative patient: long-term complications of gastrointestinal surgery

OBJECTIVES

The objectives of this review are (1) to become acquainted with the long-term complications of surgery of the gastrointestinal tract, and (2) to appreciate the appropriate use of imaging in the assessment of long-term complications.

BACKGROUND

Gastrointestinal tract surgery comprises a group of procedures performed for a variety of both benign and malignant diseases. In the late postoperative setting, adhesions and internal hernias are the most important complications. and they can be further complicated by volvulus and ischemia. At present, computed tomography (CT) is the workhorse for evaluating late postoperative complications. Accurate imaging assessment of patients is essential for adequate treatment planning.

IMAGING FINDINGS OR PROCEDURE DETAILS

In this pictorial essay we will review the most frequent long-term complications after gastrointestinal surgery, including adhesions, afferent loop syndrome, closed-loop obstruction, strangulated obstruction, internal hernias, external hernias, anastomotic strictures and disease recurrence. Examples will be depicted using iconography from the authors' imaging department.

CONCLUSIONS

Knowledge of the most frequent complications after gastrointestinal surgery in the late postoperative period is of paramount importance for every radiologist, so that potentially life-threatening situations can be promptly diagnosed and adequate therapy can be planned.

TEACHING POINTS

• Long-term postoperative complications of gastrointestinal tract surgery can be divided into procedure-related and disease-related categories. • The most common procedure-related complications are internal hernias and adhesions. • The most frequent disease-related complications are mainly associated with neoplastic or inflammatory recurrence. • Computed tomography is the most useful examination when such complications are suspected.

Ischemia and infarction of the intestine related to obstruction

In the acute obstructive syndrome, beyond the evaluation of the morphologic findings of the intestine (e.g. dilation, air-fluid level, whirl sign, transition point), it is important to consider the pathophysiology of the bowel wall in order to better estimate the status of viability, the degree of the obstruction and the presence of the intestinal ischemic complications or infarction: the intestine is a dynamic system and the same pathological condition can appear in different forms, depending on the stage of disease. MDCT examination could be of help in differentiating various type and degree of disease of the intestinal ischemia correlated to obstruction.