Current concepts in imaging of small bowel obstruction

Pearls and Pitfalls of Imaging Small Bowel Obstruction

Small bowel obstruction (SBO) is a common condition encountered by radiologists in the evaluation of patients with abdominal pain, and is an important diagnosis to be comfortable with given substantial associated morbidity and mortality. In this review, we summarize an imaging approach to evaluating patients with suspected SBO, discuss the role of certain imaging modalities such as radiography and small bowel follow through, CT, and MRI, as well as review some common and also less common causes of SBO such as internal hernia. We will also discuss tailoring the imaging approach to address specific clinical questions and special patient populations such as imaging the pregnant patient with suspected SBO, and the inflammatory bowel disease patient.

Crohn's Disease: Radiological Answers to Clinical Questions and Review of the Literature

Background: Crohn's disease (CD) is a chronic, progressive inflammatory condition, involving primarily the bowel, characterized by a typical remitting-relapsing pattern. Despite endoscopy representing the reference standard for the diagnosis and assessment of disease activity, radiological imaging has a key role, providing information about mural and extra-visceral involvement. Methods: Computed Tomography and Magnetic Resonance Imaging are the most frequently used radiological techniques in clinical practice for both the diagnosis and staging of CD involving the small bowel in non-urgent settings. The contribution of imaging in the management of CD is reported on by answering the following practical questions: (1) What is the best technique for the assessment of small bowel CD? (2) Is imaging a good option to assess colonic disease? (3) Which disease pattern is present: inflammatory, fibrotic or fistulizing? (4) Is it possible to identify the presence of strictures and to discriminate inflammatory from fibrotic ones? (5) How does imaging help in defining disease extension and localization? (6) Can imaging assess disease activity? (7) Is it possible to evaluate post-operative recurrence? Results: Imaging is suitable for assessing disease activity, extension and characterizing disease patterns. CT and MRI can both answer the abovementioned questions, but MRI has a greater sensitivity and specificity for assessing disease activity and does not use ionizing radiation. Conclusions: Radiologists are essential healthcare professionals to be involved in multidisciplinary teams for the management of CD patients to obtain the necessary answers for clinically relevant questions.

Does the use of computed tomography scenogram alone enable diagnosis in cases of bowel obstruction?

BACKGROUND

Ileus is a pathological condition of the abdomen that presents as a medical emergency. It is characterized by potential complications such as perforation and ischemia, which can lead to significant morbidity and mortality if not promptly addressed. The successful management of ileus relies heavily on the timely and precise identification of the condition. While conventional radiography (CR) is commonly used as the primary diagnostic tool, its accuracy in identifying obstructions ranges from 46% to 80%. Furthermore, the diagnostic accuracy of identifying the location and etiology of intestinal obstruction by CR is limited, therefore making computed tomography (CT) the ideal imaging modality in this regard.

AIM

To determine the presence of acute bowel obstruction (BO) on abdominal CT scenogram images and the accuracy of determining its possible location, taking into account the experience of the observers.

METHODS

A retrospective screening was conducted on an ensemble of 46 individuals who presented to the emergency department between January 2021 and January 2022 with severe abdominal pain and were subsequently monitored for suspected ileus. The abdominal CT scans of these patients were assessed by three radiologists with varying levels of experience (1, 3, and 10 years) at different intervals (1 mo apart). The evaluation focused on determining the presence or absence of BO, as well as identifying the potential location of the obstruction (small bowel or large bowel). The study employed Kappa statistics to assess inter-observer variances, while the McNamer test was used to evaluate obstruction and segmentation discrepancies between observations. A significance level of P < 0.05 was determined to indicate statistical significance.

RESULTS

Out of the total sample size of 46 patients, 15 individuals (32.6%) were identified as female, while the remaining 31 individuals (67.4%) were identified as male. The ultimate diagnosis of 42 instances (91.3%) indicated ileus resulting from mechanical obstruction (MO). Among these patients, 14 (33%) experienced obstruction in the large bowel (LB), while 28 (66%) experienced obstruction in the small bowel (SB). The initial evaluation yielded sensitivity rates of 76.19%, 83.31%, and 83.33%, and diagnostic accuracy rates of 69.56%, 76.08%, and 80.43% for the detection of BO among the three observers. The initial study revealed that the average sensitivity of three observers in detecting the presence of ileus caused by MO was 80.94%, while the diagnostic accuracy was 75.35%. Based on the first evaluation, the senior observer demonstrated the highest sensitivity (85.71%), negative predictive value (92.60%), and diagnostic accuracy (80.43%) when accurately estimating the thick and thin segmentation, as per the final diagnosis. There was no statistically significant disparity observed in the sensitivities pertaining to the identification of ileus during the second assessment, as well as the precise determination of the segment level inside the LB or SB, when comparing the second and third observers. Nevertheless, although there was no statistically significant alteration in the detection rate of ileus by the first observer, there was a notable rise in the accuracy rate of segment estimating (73.91%). The senior assessor had a higher level of accuracy in assessing the existence of ileus and segmentation compared to the other evaluators in both evaluations.

CONCLUSION

The findings of our study indicate that the sensitivity and accuracy rates of abdominal CT scenogram scans in diagnosing acute MOs are similar to or greater than those of CR. Additionally, the study revealed that radiologists with more experience demonstrated a higher likelihood of accurately predicting the existence and potential localization of MO compared to their less experienced counterparts.

Accurately evaluating for a small bowel obstruction using an abdominal radiograph, by a new method: The Bowel-Spine Ratio

INTRODUCTION

A well-established method does not exist to rule out a small bowel obstruction using an abdominal xray series with significant accuracy. The hypothesis of the study is that the ratio of an average small bowel diameter to lumbar spine diameter over 0.5 is most likely a small bowel obstruction.

METHODS

An x-ray abdominal series measurement technique was applied to 41 subjects with a chief complaint of "abdominal pain" as part of a randomized retrospective case review to predict an obstruction v. non obstruction. A total number of 81 abdominal pain subjects with a mean age of 46.7 years were selected with 40 excluded due to normal small bowel gas pattern. The subject's medical information was unknown to the authors when reading their images. The measurement technique involved averaging the largest and smallest small bowel short axis diameters with comparison to the lowest clearly visible lumbar body width. The subjects' medical course as described in the medical chart or subsequent computed tomography scans were used as the referencing standard to determine presence of obstruction vs non-obstruction.

RESULTS

This method, called the Bowel-Spine Ratio (BSR), resulted in a sensitivity of 0.882 (0.622-0.979; 95% CI), specificity of 0.957 (0.760-0.998; 95% CI), accuracy of 94.7% (80.9%-99.1%; 95% CI) and a positive likelihood ratio of 21 for predicting a small bowel obstruction.

CONCLUSION

The abdominal series Bowel-Spine Ratio is a simple yet effective technique to screen for a small bowel obstruction using limited resources and to avoid unnecessary computed tomography scans with the potential to reduce health care costs.

IMPLICATIONS FOR PRACTICE

Clinicians could have increased confidence in utilizing abdominal radiographs to evaluate for small bowel obstruction.

In-hospital management of inflammatory bowel disease

PURPOSE OF REVIEW

The management of hospitalized patients with inflammatory bowel disease (IBD) is complex. Despite considerable therapeutic advancements in outpatient ulcerative colitis and Crohn's disease management, the in-hospital management continues to lag with suboptimal outcomes. The purpose of this review is to provide a brief overview of our approach to managing patients hospitalized with acute severe ulcerative colitis (ASUC) and Crohn's disease-related complications, followed by a summary of emerging evidence for new management approaches.

RECENT FINDINGS

ASUC has seen the emergence of well validated prognostic models for colectomy as well as the development of novel treatment strategies such as accelerated infliximab dosing, Janus kinase inhibitor therapy, and sequential therapy, yet the rate of colectomy for steroid-refractory ASUC has not meaningfully improved. Crohn's disease has seen the development of better diagnostic tools, early Crohn's disease-related complication stratification and identification, as well as better surgical techniques, yet the rates of hospitalization and development of Crohn's disease-related complications remain high.

SUMMARY

Significant progress has been made in the in-hospital IBD management; however, both the management of ASUC and hospitalized Crohn's disease remain a challenge with suboptimal outcomes. Critical knowledge gaps still exist, and dedicated studies in hospitalized patients with IBD are needed to address them.

Rapunzel Syndrome: A Case of Trichobezoar with Small Bowel Complications

Introduction  Rapunzel syndrome is characterized by a large trichobezoar in the stomach with a tail extending beyond the pylorus into the small bowel, causing mechanical obstruction of the small bowel. A 7-year-old girl presented to the emergency room with severe epigastric pain. Computed tomography suggested trichobezoar causing jejuno-jejunal intussusceptions, bowel wall thickening, and dilated small bowel loops proximal to the obstruction. On laparotomy, two concealed perforations were noted at the duodenojejunal (DJ) junction and 40 cm distal to the DJ junction. An enterotomy incision was given at the antimesenteric border of the distal jejunal perforation site, and the mass was successfully extracted. Primary repair was done at the DJ perforation site, and resection was followed by an end-to-end anastomosis at the distal jejunal perforation site. Surgery confirmed a complex mass of tangled hair within the gastric cavity with a tail extending into the pylorus of the stomach and small intestine, consistent with trichobezoar.

Conclusion  Computed tomography is superior to other radiological imaging modalities for diagnosing trichobezoars as it helps diagnose and demonstrate mechanical bowel complications.

Small bowel obstruction and intestinal ischemia: emphasizing the role of MDCT in the management decision process

The objective of this article is to assess the computed tomography (CT) findings of small bowel obstruction (SBO) complicated by ischemia. SBO is a frequent clinical entity characterized by high morbidity and mortality. The radiologic aim is not just to diagnose the obstruction itself but to rule out the presence of complications related to SBO. This is crucial for differentiating which patients can be safely treated non-operatively from the ones who may need an urgent surgical approach. The main complication of SBO is intestinal ischemia. In the emergency setting, CT imaging is the modality of choice for SBO because of its ability to assess the bowel wall, the supporting mesentery and peritoneal cavity all in one. On the other hand, the radiologist who documents an intestinal ischemia should think about SBO as possible cause. In this case, the main finding which helps the radiologist in the identification of SBO is the presence of multiple and packed valvulae conniventes in the dilated bowel wall and the "transition zone" that indicates the passage between compressed and decompressed small bowel, otherwise the localization of the obstruction cause. Once the site of obstruction has been recognized, the other issue is to assess the cause of obstruction, considering that the most common cause of SBO remains "unidentified" and related to intra-abdominal adhesions. After that, the following most important point is to rule out the presence of an ischemic bowel and mesenteric changes associated to SBO. CT signs of bowel ischemia include reduced or increased bowel wall enhancement, mesenteric edema or engorgement, fluid or free air in the peritoneal cavity. This condition usually leads to an urgent laparotomy and, in some cases, to a surgical resection.

Considerations in the Management of Malignant Bowel Obstruction

Malignant bowel obstruction is a challenging clinical problem encountered in patients with advanced abdominal and pelvic malignancies. Although medical therapies form the foundation of management, some patients may be suitable candidates for surgical and procedural interventions. The literature is composed primarily of retrospective single-institution experiences and the results of prospective trials are pending. Given the high symptom burden and limited life expectancy of these patients, management may be best informed by multidisciplinary teams with relevant expertise.

Computed Tomography Findings Predicting the Need for Surgery in Cases of Small Bowel Obstruction: Emphasis on Duodenal Distension

OBJECTIVE

The aim of the study is to retrospectively evaluate the utility of computed tomography (CT) findings, especially newly defined duodenal distension, for predicting the need to operate on small bowel obstruction (SBO) cases.

METHODS

During a 51-month period, 228 patients (100 women and 128 men; mean age, 55 years) were included in this study, among 438 patients who were hospitalized with a prediagnosis of SBO. The final study population was then divided into 2 groups: a surgery group (n = 76) and a conservative group (n = 152). The CT findings of the SBO patients whose treatment decisions and outcomes were unknown were examined by 2 gastrointestinal radiologists with consensus. Statistical analyses were conducted using univariate and binary logistic regression analyses.

RESULTS

According to the univariate analysis, the degree of obstruction (P = 0.001), small bowel diameter (P = 0.014), and presence of mesenteric fluid (P < 0.001), intraperitoneal free fluid (P = 0.04), intra-abdominal free gas (P < 0.001), and duodenal distension (P < 0.001) showed statistically significant differences between the surgery and conservative groups. However, there were no statistically significant group differences regarding the presence of a transition point, small bowel feces or mesenteric congestion. According to the binary logistic regression analysis, the degree of obstruction (P = 0.012), presence of mesenteric fluid (P = 0.008), intra-abdominal free gas (P = 0.019), and duodenal distension (P < 0.001) were significant predictors of the need for surgery in SBO cases.

CONCLUSIONS

Duodenal distension as a CT finding predicted the need for surgery in SBO cases.

Role of Multidetector Computed Tomography with Multiplanar and Curved Multiplanar Reformations in the Detection of Cause of Intestinal Obstruction: A Tertiary Care Experience

Objective To determine the role of multidetector computed tomography (MDCT) with multiplanar (MPR) and curved multiplanar reformations (CMPR) in the detection of the cause of intestinal obstruction. Materials and methods A retrospective analysis of 200 patients with a clinical suspicion of intestinal obstruction referred to the department of radiology, Dr. Ziauddin University Hospital, Clifton campus, from September 2016 to October 2019, was done. All patients who underwent an MDCT scan with oral and intravenous (I/V) contrast were included in the study. Patients with deranged serum creatinine and an allergic reaction to contrast were excluded from the study. MPR and CMPR images were acquired in each patient in addition to routine axial images. The causes of intestinal obstruction as determined by a computed tomography (CT) scan were confirmed on surgery and colonoscopy. The CT scans were analyzed by an independent radiologist with five years of experience blinded to the surgical and colonoscopy findings in detecting the cause of bowel obstruction using the axial, MPR, and CMPR images. Data analysis was done on IBM SPSS Statistics for Windows, Version 20.0 (IBM Corp., Armonk, NY). Results Out of 200 patients with a clinical suspicion of intestinal obstruction, 120 patients with intestinal obstruction was confirmed on CT scan. Fifty-eight patients were males (48.33%) and 62 patients were females (51.66%) with a male-to-female ratio of 1:1.06. The mean age of the patients was 54.7 years (age range from 06 years to 85 years). Abdominal distension was the most common presentation seen in 37 patients (30.83%) followed by vomiting in 25 patients (20.83%). Small bowel obstruction was seen in 96 patients (80.00%) with the ileum being the most common site of obstruction seen in 76 patients (63.33%). Among the patients with the ileum being the site of obstruction, distal ileal obstruction was seen in the majority of patients (30 patients, with a frequency of 25.00%). Twenty-three patients (19.16%) had a large bowel obstruction, with sigmoid colon involvement seen as the most common site in 10 patients (8.33%). Adhesions were the leading extrinsic cause of bowel obstruction seen in 32 patients (26.6%). Intraluminal causes of obstruction were seen in 36 patients (30.0%) with carcinoma being the commonest cause (12 patients with a frequency of 10.0%). A foreign body is the primary cause of intraluminal obstruction (three patients, with a frequency of 2.5%). The sensitivity, specificity, positive predictive value, and negative predictive value of MDCT were 86.2%, 92.7%, 90.1%, and 96.4%, respectively. Conclusion MDCT has high sensitivity and specificity to diagnose and determine the cause of bowel obstruction. It not only determines the site of obstruction but also the cause of obstruction, including intrinsic, extrinsic, and intraluminal causes.

Emergency Medicine Evaluation and Management of Small Bowel Obstruction: Evidence-Based Recommendations

BACKGROUND

Small bowel obstruction (SBO) is a commonly diagnosed disease in the emergency department (ED). Recent literature has evaluated the ED investigation and management of SBO.

OBJECTIVE

This review evaluates the ED investigation and management of adult SBO based on the current literature.

DISCUSSION

SBO is most commonly due to occlusion of the small intestine, resulting in fluid and gas accumulation. This may progress to mucosal ischemia, necrosis, and perforation. A variety of etiologies are present, but in adults, adhesions are the most common cause. Several classification systems are present. However, the most important distinction is complete vs. partial and complicated vs. simple obstruction, as complete complicated SBO more commonly requires surgical intervention. History and physical examination can vary, but the most reliable findings include prior abdominal surgery, history of constipation, abdominal distension, and abnormal bowel sounds. Signs of strangulation include fever, hypotension, diffuse abdominal pain, peritonitis, and several others. Diagnosis typically requires imaging, and though plain radiographs are often ordered, they cannot exclude the diagnosis. Computed tomography and ultrasound are reliable diagnostic methods. Management includes intravenous fluid resuscitation, analgesia, and determining need for operative vs. nonoperative therapy. Nasogastric tube is useful for patients with significant distension and vomiting by removing contents proximal to the site of obstruction. Surgery is needed for strangulation and those that fail nonoperative therapy. Surgical service evaluation and admission are recommended.

CONCLUSION

SBO is a common reason for admission from the ED. Knowledge of recent literature can optimize diagnosis and management.

Small-Bowel Obstruction Secondary to Ileal Trichobezoar in a Patient with Rapunzel Syndrome

Bezoars are conglomerations of undigested foreign material retained in the gastrointestinal tract. Trichobezoar is a compact conglomeration of swallowed hair and constitutes less than 6% of all bezoars. Their most frequent location is in the stomach but they may extend through the pylorus into the small bowel. This condition is known as Rapunzel syndrome. Many patients may remain asymptomatic or present a mild form of the disease characterized by abdominal pain, early satiety, nausea, and vomiting. Complications may manifest as gastric outlet obstruction or bleeding, and intestinal obstruction. A 15-year-old female patient presented with clinical findings of intestinal obstruction. The patient suffered from depressive and anxiety disorders and trichotillomania, although trichophagy could not be assured. Alopecia circumscripta and irregular hair length on the scalp were identified. A computed tomography (CT) scan showed two images highly suggestive of trichobezoars, one in the stomach and the second one causing obstruction at the ileocecal valve. At laparotomy, both a mobile gastric trichobezoar with a tail extending to the duodenum and a trichobezoar causing obstruction at the ileocecal valve were removed. The postoperative course was uneventful. The passage of a detached trichobezoar fragment in a patient with Rapunzel syndrome may cause intestinal obstruction. CT is the preferred image modality for the evaluation of suspected trichobezoars in order to characterize their size and locations, the presence and level of obstruction, and complications such as ischemia or perforation. A case of small-bowel obstruction secondary to ileal trichobezoar in a patient with Rapunzel syndrome is herein reported.

Accuracy of Plain Abdominal Radiography in the Differentiation between Small Bowel Obstruction and Small Bowel Ileus in Acute Abdomen Presenting to Emergency Department

Introduction

Our purpose was to evaluate whether plain abdominal radiography (PAR) could accurately differentiate between small bowel obstruction (SBO) and small bowel ileus (SBI) in an emergency setting. We also evaluated the value of known classic signs on the PAR for differentiating between SBO and SBI.

Methods

This retrospective study included 216 emergency room patients who had small bowel distension (maximal small bowel diameter ≥2.5 cm) on the PAR and who underwent successive abdominal computed tomography. One radiologist and one emergency physician retrospectively reviewed PAR in consensus, unaware of the patients' clinical data; they divided the patients into an SBO group and an SBI group according to the radiographic findings. Presence or numeric values of 10 radiographic signs were also recorded. Final diagnoses of SBO and SBI were established by a combined analysis of medical charts, surgical records, radiographic findings on abdominal computed tomography, and small bowel studies. The differential diagnoses based on PAR and the final diagnoses were compared, and the sensitivity and specificity of PAR were calculated. We also evaluated the differences among 10 radiographic signs between the final SBO and SBI groups.

Results

Sensitivity and specificity of PAR for SBO were 82.0% and 92.4%, respectively. Among the 10 radiographic signs, all except maximal colon diameter were statistically significant predictors on the final diagnosis.

Conclusions

PAR is an accurate and effective initial imaging modality for differentiating between SBO and SBI in an emergency setting, and most of the classic radiographic signs have a diagnostic value.

Acute Bowel Computed Tomography

Acute abdominal pain is a common presenting complaint in the emergency department. Increasingly, computed tomography is utilized for evaluating these patients. Radiologists are therefore expected to be familiar with the pertinent clinical and radiologic information related to acute bowel pathology. This primer will review the need-to-know and latest updates related to computed tomography evaluation of acute bowel pathology.

Diagnosis of Small Bowel Obstruction using Targeted Enterography During Nasointestinal Decompression

The aim of the study is to investigate the efficacy of using targeted enterography during intestinal decompression in the diagnosis of small bowel obstruction (SBO). Thirty-five patients with SBO and who had neither strangulation nor other contradictions received intestinal decompression, under the guidance of X-ray, using a 300-cm-long nasointestinal tube which reached the upper jejunum. Contrast radiography of intestines was performed when the tip of the decompression tube reached the obstruction by administering double-contrast medium, containing 20-100 ml 76 % gastrografin and 50-200 ml air, through the nasointestinal tube. Serial erect and supine plain abdominal radiographs were obtained. Intubation procedure was successful in all 35 patients. SBO was resolved in 20 patients, alleviated in 15 patients and 10 patients received surgery. Selective enterographies showed clear and high quality images. Imaging findings demonstrated no significant abnormality in six patients and adhesive SBO in 15. Furthermore, intestinal tumours were identified in four patients of which three were metastatic tumours and one was an original intestinal cancer; Crohn's disease was confirmed in three patients; radiation enteritis in three (one of them was misdiagnosed and was then confirmed as metastatic tumour during surgery); enteric intussusception was found in two patients; polyps in one patient and carcinoma of the ascending colon in one. Targeted enterography during nasointestinal decompression allows confirmation of pathology of SBO by direct identification of the location, the extent and aetiology of obstruction, thereby providing evidence for the choice of timing and strategy of surgery.

A case report of small bowel obstruction secondary to congenital peritoneal band in adult

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A case of small bowel obstruction due to peritoneal congenital band is presented.

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Computed tomography is effective for diagnosis.

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The laparoscopic approach for surgical treatment should be intended initially for its feasibility and benefits.

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A quick management is necessary to avoid intestinal necrosis.

Introduction

Small bowel obstruction (SBO) is common in adult surgical procedures, mainly due to postoperative adhesions. Acute SBO in adults without history of abdominal surgery, trauma or clinical hernia is less common and has various etiologies. Congenital band is an extremely rare cause.

Presentation of case

A 56-year-old man was admitted to our hospital with a two-day history of abdominal pain and bilious vomiting. He had no history of abdominal surgery or any other medical problems. A contrast-enhanced CT of the abdomen showed a distention of small bowel loops with transition point in the right hypochondrium. Distended loops of small bowel were located in the left side of the abdomen, whereas collapsed loops was located in the right side. The normal bowel wall enhancement was preserved. After initial treatment with intravenous fluid and nasogastric suction, he was operated. At laparoscopy a band obstructing the ileum was clearly observed. This anomalous band extending from gallbladder to transverse mesocolon caused a small window leading to internal herniation of the small bowel and obstruction. The band was coagulated and divided. Postoperative outcome was uneventful and the patient was discharged on the second postoperative day. There was no recurrence of symptoms on subsequent follow-up.

Discussion

Congenital peritoneal bands are not frequently encountered in surgical practice and these bands are often difficult to classify and define. Diagnosis of acute intestinal obstruction due to CPB must be included in the differential diagnosis in any patient with no history of abdominal surgery, trauma, clinical hernia, inflammatory bowel disease or peritoneal tuberculosis.

Conclusion

Despite technological advances in radiology preoperative diagnosis remains difficult, however the diagnosis of SBO due to CPB must be considered in any patient with no history of abdominal surgery, Trauma or clinical hernia consulting for occlusive syndrome. The laparoscopic approach should be intended initially for its feasibility and benefits.

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.

Optimal Diagnostic Approaches for Patients with Suspected Small Bowel Disease

While the domain of gastrointestinal endoscopy has made great strides over the last several decades, endoscopic assessment of the small bowel continues to be challenging. Recently, with the development of new technology including video capsule endoscopy, device-assisted enteroscopy, and computed tomography/magnetic resonance enterography, a more thorough investigation of the small bowel is possible. In this article, we review the systematic approach for patients with suspected small bowel disease based on these advanced endoscopic and imaging systems.

The Vomiting Patient: Small Bowel Obstruction, Cyclic Vomiting, and Gastroparesis

Vomiting and abdominal pain are common in patients in the emergency department. This article focuses on small bowel obstruction (SBO), cyclic vomiting, and gastroparesis. Through early diagnosis and appropriate management, the morbidity and mortality associated with SBOs can be significantly reduced. Management of SBOs involves correction of physiologic and electrolyte disturbances, bowel rest and removing the source of the obstruction. Treatment of acute cyclic vomiting is primarily directed at symptom control, volume and electrolyte repletion, and appropriate specialist follow-up. The mainstay of therapy for gastroparesis is metoclopramide.

Anesthetic management of intestinal obstruction: A postgraduate educational review

Intestinal obstruction is associated with significant morbidity and mortality. Scientific assessment of the cause, site of obstruction, appropriate correction of the fluid deficit and electrolyte imbalance with preoperative stabilization of blood gases is ideal as a preoperative workup. Placement of a preoperative epidural catheter especially in the thoracic interspace takes care of perioperative pain and stress reduction. Intraoperative management by controlled general anesthesia administering a relative high inspired fraction of oxygen with invasive monitoring in selected sick cases is mandatory. Preoperative monitoring and stabilizing raised intra-abdominal pressure reduces morbidity. Caution should be exercised during opening and closure of abdomen to avoid cardiorespiratory ill effects. There should be an emphasis on avoiding hypothermia. The use of nonsteroidal anti-inflammatory drugs may worsen sick, fragile patients. The use of sugammadex rather than neostigmine will obscure certain controversies in the healing of intestinal anastomotic site. Replacement of blood loss continued correction of fluids and electrolytes with possible postoperative mechanical ventilation in sick cases may improve outcomes in these patients.

Multimodality approach for imaging of non-traumatic acute abdominal emergencies

"Acute abdomen" includes spectrum of medical and surgical conditions ranging from a less severe to life-threatening conditions in a patient presenting with severe abdominal pain that develops over a period of hours. Accurate and rapid diagnosis of these conditions helps in reducing related complications. Clinical assessment is often difficult due to availability of over-the-counter analgesics, leading to less specific physical findings. The key clinical decision is to determine whether surgical intervention is required. Laboratory and conventional radiographic findings are often non-specific. Thus, cross-sectional imaging plays a pivotal role for helping direct management of acute abdomen. Computed tomography is the primary imaging modality used for these cases due to fast image acquisition, although US is more specific for conditions such as acute cholecystitis. Magnetic resonance imaging or ultrasound is very helpful in patients who are particularly sensitive to radiation exposure, such as pregnant women and pediatric patients. In addition, MRI is an excellent problem-solving modality in certain conditions such as assessment for choledocholithiasis in patients with right upper quadrant pain. In this review, we discuss a multimodality approach for the usual causes of non-traumatic acute abdomen including acute appendicitis, diverticulitis, cholecystitis, and small bowel obstruction. A brief review of other relatively less frequent but important causes of acute abdomen, such as perforated viscus and bowel ischemia, is also included.

Clinical and diagnostic significance of enteroclysis through nasointestinal decompression intubation

To study the clinical and diagnostic significance of enteroclysis through nasointestinal decompression intubation, thirty-five patients with small bowel obstruction were enrolled. A nasointestinal catheter of 300 cm was placed through the nasal cavity then pushed to the upper jejunum under X-ray realtime monitoring. The patients underwent intra-small-intestinal suction therapy reducing or relieving the obstruction after 3 days. As the catheter reached the lesions, we conducted selective imaging. Using fluoroscopy, we injected 20-100 ml meglumine diatrizoate 76 % and 50-200 ml air via the decompression suction port to produce a double-contrast radiography. The catheter was then retrieved to the upper jejunum, and the X-ray of the small intestine was obtained. All 35 patients had successful intubations. The decompression treatment resolved symptoms in 20 cases and alleviated symptoms in 15 cases. Ten cases underwent surgery. The images obtained by infusing meglumine diatrizoate through the decompression catheter were of good quality. Among the 35 cases, six were absent of any distinct abnormal signs on the X-ray, 15 had adhesive ileus, four had small bowel tumor (three metastatic tumor, one small bowel cancer), three had Crohn's disease, three had radiation enteritis (one of the three was mistaken for small bowel metastatic tumor), two had enteric intussusception, one had a polyp in the small intestine, one had ascending colon cancer. The nasointestinal decompression intubation under X-ray monitoring serves a dual function for patients with intestine obstruction, by decompressing the small bowel and examining the small intestinal radiographically. The X-rays can confirm the obstruction and provide guidelines for surgery.

Review of small-bowel obstruction: the diagnosis and when to worry

This is a review of small-bowel obstruction written primarily for residents. The review focuses on radiography and computed tomography (CT) for diagnosing small-bowel obstruction and CT for determining complications. (©) RSNA, 2015.

Surgical indicators for the operative treatment of acute mechanical intestinal obstruction due to adhesions

Purpose

Our aim was to investigate the predictive factors indicating strangulation, and the requirement for surgery in patients with acute mechanical intestinal obstruction due to adhesions.

Methods

This study retrospectively evaluated the records of patients with adhesive acute mechanical intestinal obstruction. The surgical treatment (group S), conservative treatment (group C), intraoperative bowel ischemia (group I), and intraoperative adhesion only (group A) groups were statistically evaluated according to the diagnostic and surgical parameters.

Results

The study group of 252 patients consisted of 113 women (44.8%), and 139 men (55.2%). The mean age was 62.79 ± 18.08 years (range, 20-98 years). Group S consisted of 50 patients (19.8%), and 202 (80.2%) were in group C. Group I consisted of 19 patients (38%), where as 31 (62%) were in group A. In group S, the prehospital symptomatic period was longer, incidence of fever was increased, and elevated CRP levels were significant (P < 0.05). Plain abdominal radiography, and abdominal computerized tomography were significantly sensitive for strangulation (P < 0.05). The elderly were more prone to strangulation (P < 0.05). Fever, rebound tendernes, and urea & creatinine levels were significantly higher in the presence of strangulation (P < 0.05, P < 0.05, and P < 0.05, consecutively).

Conclusion

Fever, rebound tenderness, urea & creatinine levels, plain abdominal radiography, and abdominal computerized tomography images were important indicators of bowel ischemia. Longer prehospital symptomatic period was related with a tendency for surgical treatment, and the elderly were more prone to strangulation. CRP detection was considered to be useful for the decision of surgery, but not significantly predictive for strangulation.

Early diagnosis of bowel obstruction and strangulation by computed tomography in emergency department

BACKGROUND

Closed loop bowel obstruction is a specific type of mechanical obstruction with a high risk of strangulation and bowel infarction, especially in the small bowel. It is associated with a high mortality rate. Hence, it is important for emergency physicians to identify the presence of strangulation, while making the diagnosis of closed loop small bowel obstruction.

METHODS

We reported three patients with strangulated closed loop small bowel obstruction associated with severe abdominal pain, who had been treated at the emergency department. Urgent computerized tomography was performed in the patients.

RESULTS

Two patients were discharged with stable conditions, and one patient died after hemodialysis.

CONCLUSION

Urgent computerized tomography of the abdomen serves as an important diagnostic tool in view of its ability to detect the site, level and cause of obstruction along with the distinctive CT appearance of closed loop small bowel obstruction and signs of ischemia. Early definitive diagnosis will guide subsequent management and improve outcomes.

Laparoscopic lysis for jejunostomy-related ileus following laparoscopy-assisted total gastrectomy: a case report

A 54-year-old man was admitted to our hospital with severe nausea, vomiting and abdominal pain. He had had laparoscopy-assisted total gastrectomy with Roux-en-Y reconstruction and tube jejunostomy for gastric cancer 2 years earlier. Abdominal CT revealed that the duodenum and upper jejunum were markedly dilated and that the dilated jejunum had collapsed at the jejunostomy site. Emergency laparoscopic surgery with three ports was performed for jejunostomy-related ileus. Abdominal adhesion was very small, and the Roux-en-Y limb was rotated counterclockwise at the jejunostomy site. A magnified laparoscopic view showed that the site of peritoneopexy was the axis of rotation. After the axis was dissected with a Harmonic scalpel, the rotation was released immediately. The patient's postoperative course was uneventful and he was discharged 4 days after the operation. Because the axis of rotation was identified easily by laparoscope, laparoscopic surgery was a safe and useful technique for a patient with jejunostomy-related ileus.

Meaning of free intraperitoneal fluid in small-bowel obstruction: preliminary results using high-frequency microsonography in a rat model

OBJECTIVES

The aim of this study was to detect the onset, evolution, and meaning of extraluminal free fluid in a rat model of small-bowel obstruction using high-frequency microsonography.

METHODS

Small-bowel obstruction was surgically created in 8 rats divided into 2 groups of 4 rats each. All rats were examined by high-frequency microsonography to monitor the evolution of small-bowel obstruction and the abdominal sonographic findings. In group 2 rats, the obstruction was resolved 2 hours after surgery.

RESULTS

In all rats, free peritoneal fluid was detected just near the obstructed loop after 1 hour and in the hepatorenal recess after 2 hours. These features progressively increased in the following hours in group 1 rats. In group 2, the amount of free fluid decreased shortly after removing the obstruction.

CONCLUSIONS

Free fluid is an early finding in small-bowel obstruction, and the increase or decrease of its amount is correlated with the worsening or resolution of the obstruction.

Early MRI findings of small bowel obstruction: an experimental study in rats

PURPOSE

This study was undertaken to identify the early magnetic resonance imaging (MRI) findings of small bowel obstruction (SBO) and to analyse their evolution over time comparing them with histological findings.

MATERIALS AND METHODS

SBO was surgically induced in 10 rats divided into two groups monitored at predetermined time points until the 8th hour: group 1, macroscopically observed and group 2, investigated with 7-Tesla micro-MRI (7 T μ-MR). At the end of observation, the bowel was excised for histological analysis.

RESULTS

7 T μ-MRI T2-w sequences acquired 15 min after SBO, showed early evidence of bowel wall hyperintensity and a small amount of peritoneal free fluid. At 1 h, a hyperintensity of the loop proximal to the obstruction was found and, after 4 h, free fluid between the loops, bowel wall thickening and increased wall hyperintensity were also found. After 6 h hypotonic reflex ileus (only gas-filled dilated loops) was detected, which became paralytic ileus (dilation with air-fluid levels) after 8 h. The MRI findings were all confirmed at histological examination.

CONCLUSIONS

This study allows definition of the early MRI features of SBO (peritoneal free fluid and hyperintensity of the injured bowel) and their chronological evolution, also confirmed by histological examination. Our data suggest a potential role of MR imaging in the early diagnostic assessment and management of patients with SBO. The chance to achieve an early detection of bowel injury and to correlate the histological pattern with imaging findings could contribute to a finer and earlier diagnosis and a more effective treatment.

Acute obstruction

Acute obstruction of the gastrointestinal or biliary tract represents a common problem for acute care surgeons. It is with appropriate clinical evaluation, planning, and physical examination follow-up that acute care surgeons are able to appropriately diagnose, manage, and resolve this difficult group of surgical problems and minimize the morbidity associated with each.

Acute GI obstruction

Acute gastrointestinal obstruction occurs when the normal flow of intestinal contents is interrupted. The blockage can occur at any level throughout the gastrointestinal tract. The clinical symptoms depend on the level and extent of obstruction. Various benign and malignant processes can produce acute gastrointestinal obstruction, which often represents a medical emergency because of the potential for bowel ischemia leading to perforation and peritonitis. Early recognition and appropriate treatment are thus essential. The typical clinical symptoms associated with obstruction include nausea, vomiting, dysphagia, abdominal pain and failure to pass bowel movements. Abdominal distention, tympany due to an air-filled stomach and high-pitched bowel sounds suggest the diagnosis. The diagnostic process involves imaging including radiography, ultrasonography, contrast fluoroscopy and computer tomography in less certain cases. In patients with uncomplicated obstruction, management is conservative, including fluid resuscitation, electrolyte replacement, intestinal decompression and bowel rest. In many cases, endoscopy may aid in both the diagnostic process and in therapy. Endoscopy can be used for bowel decompression, dilation of strictures or placement of self-expandable metal stents to restore the luminal flow either as a final treatment or to allow for a delay until elective surgical therapy. When gastrointestinal obstruction results in ischemia, perforation or peritonitis, emergency surgery is required.

Adult small bowel obstruction

BACKGROUND

Small bowel obstruction (SBO) is a clinical condition that is often initially diagnosed and managed in the emergency department (ED). The high rates of potential complications that are associated with an SBO make it essential for the emergency physician (EP) to make a timely and accurate diagnosis.

OBJECTIVES

The primary objective was to perform a systematic review and meta-analysis of the history, physical examination, and imaging modalities associated with the diagnosis of SBO. The secondary objectives were to identify the prevalence of SBO in prospective ED-based studies of adult abdominal pain and to apply Pauker and Kassirer's threshold approach to clinical decision-making to the diagnosis and management of SBO.

METHODS

MEDLINE, EMBASE, major emergency medicine (EM) textbooks, and the bibliographies of selected articles were scanned for studies that assessed one or more components of the history, physical examination, or diagnostic imaging modalities used for the diagnosis of SBO. The selected articles underwent a quality assessment by two of the authors using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Data used to compile sensitivities and specificities were obtained from these studies and a meta-analysis was performed on those that examined the same historical component, physical examination technique, or diagnostic test. Separate information on the prevalence and management of SBO was used in conjunction with the meta-analysis findings of computed tomography (CT) to determine the test and treatment threshold.

RESULTS

The prevalence of SBO in the ED was determined to be approximately 2% of all patients who present with abdominal pain. Having a previous history of abdominal surgery, constipation, abnormal bowel sounds, and/or abdominal distention on examination were the best history and physical examination predictors of SBO. X-ray was determined to be the least useful imaging modality for the diagnosis of SBO, with a pooled positive likelihood ratio (+LR) of 1.64 (95% confidence interval [CI] = 1.07 to 2.52). On the other hand, CT and magnetic resonance imaging (MRI) were both quite accurate in diagnosing SBO with +LRs of 3.6 (5- to 10-mm slices, 95% CI = 2.3 to 5.4) and 6.77 (95% CI = 2.13 to 21.55), respectively. Although limited to only a select number of studies, the use of ultrasound (US) was determined to be superior to all other imaging modalities, with a +LR of 14.1 (95% CI = 3.57 to 55.66) and a negative likelihood ratio (-LR) of 0.13 (95% CI = 0.08 to 0.20) for formal scans and a +LR of 9.55 (95% CI = 2.16 to 42.21) and a -LR of 0.04 (95% CI = 0.01 to 0.13) for beside scans. Using the CT results of the meta-analysis for the 5- to 10-mm slice subgroup as well as information on intravenous (IV) contrast reactions and nasogastric (NG) intubation management, the pretest probability threshold for further testing was determined to be 1.5%, and the pretest probability threshold for beginning treatment was determined to be 20.7%.

CONCLUSIONS

The potentially useful aspects of the history and physical examination were limited to a history of abdominal surgery, constipation, and the clinical examination findings of abnormal bowel sounds and abdominal distention. CT, MRI, and US are all adequate imaging modalities to make the diagnosis of SBO. Bedside US, which can be performed by EPs, had very good diagnostic accuracy and has the potential to play a larger role in the ED diagnosis of SBO. More ED-focused research into this area will be necessary to bring about this change.

Effectiveness of MR enterography for the assessment of small-bowel diseases beyond Crohn disease

The use of cross-sectional imaging techniques for the noninvasive evaluation of small-bowel disorders is increasing. The effectiveness of magnetic resonance (MR) enterography for the evaluation of Crohn disease, in particular, is well described in the literature. In addition, MR enterography has an evolving though less well documented role to play in the evaluation of other small-bowel diseases, including various benign and malignant neoplasms arising in isolation or in polyposis syndromes such as Peutz-Jeghers, inflammatory conditions such as vasculitis and treatment-induced enteritis, infectious processes, celiac disease, diverticular disease, systemic sclerosis, and bowel duplication. MR enterography may be useful also for the evaluation of intermittent and low-grade small-bowel obstructions. Advantages of MR imaging over computed tomography (CT) for enterographic evaluations include superb contrast resolution, lack of associated exposure to ionizing radiation, ability to acquire multiplanar primary image datasets, ability to acquire sequential image series over a long acquisition time, multiphasic imaging capability, and use of intravenous contrast media with better safety profiles. MR enterography also allows dynamic evaluations of small-bowel peristalsis and distensibility of areas of luminal narrowing and intraluminal masses by repeating sequences at different intervals after administering an additional amount of the oral contrast medium. Limitations of MR enterography in comparison with CT include higher cost, less availability, more variable image quality, and lower spatial resolution. The advantages and disadvantages of MR enterography performed with ingestion of the oral contrast medium relative to MR enteroclysis performed with infusion of the oral contrast medium through a nasoenteric tube are less certain.

Evaluation and management of small-bowel obstruction: an Eastern Association for the Surgery of Trauma practice management guideline

BACKGROUND

Small-bowel obstruction (SBO) represents as many as 16% of surgical admissions and more than 300,000 operations annually in the United States. The optimal strategies for the diagnosis and management of SBO continue to evolve secondary to advances in imaging techniques, critical care, and surgical techniques. This updated systematic literature review was developed by the Eastern Association for the Surgery of Trauma to provide up-to-date evidence-based recommendations for SBO.

METHODS

A search of the National Library of Medicine MEDLINE database was performed using PubMed interface for articles published from 2007 to 2011.

RESULTS

The search identified 53 new articles that were then combined with the 131 studies previously reviewed by the 2007 guidelines. The updated guidelines were then presented at the 2012 annual EAST meeting.

CONCLUSION

Level I evidence now exists to recommend the use of computed tomographic scan, especially multidetector computed tomography with multiplanar reconstructions, in the evaluation of patients with SBO because it can provide incremental clinically relevant information over plains films that may lead to changes in management. Patients with evidence of generalized peritonitis, other evidence of clinical deterioration, such as fever, leukocytosis, tachycardia, metabolic acidosis, and continuous pain, or patients with evidence of ischemia on imaging should undergo timely exploration. The remainder of patients can safely undergo initial nonoperative management for both partial and complete SBO. Water-soluble contrast studies should be considered in patients who do not clinically resolve after 48 to 72 hours for both diagnostic and potential therapeutic purposes. Laparoscopic treatment of SBO has been demonstrated to be a viable alternative to laparotomy in selected cases.

Errors in the radiological evaluation of the alimentary tract: part II

Plain abdominal radiography and computed tomographic (CT) enteroclysis are 2 essential radiological investigations in the study of gastrointestinal tract. Errors in patient preparation, execution, and interpretation may lead to severe consequences in the diagnosis and thus in patient outcome. Abdominal radiography is one of the most frequently requested radiographic examinations, and has an established role in the assessment of the acute abdomen. CT enteroclysis has revolutionized the assessment of small-bowel pathology, especially in patients with inflammatory bowel. The purpose of this article is to describe the pitfalls in the execution and interpretation of plain abdominal film and CT enteroclysis.

Developing a new measure of small bowel peristalsis with dynamic MR: a proof of concept study

BACKGROUND

Small bowel peristalsis is a complex of many individual motion elements. Although each element of peristalsis can be measured there is no current global measure of peristalsis.

PURPOSE

To examine the feasibility of automated computerized assessment of global small bowel motility using simple computational methods.

MATERIAL AND METHODS

Coronal dynamic MR images were obtained from five healthy volunteers who had fasted for 9 h and drunk 1.5 L of water. Images were taken using single breath-hold and ECG triggering. Acquisitions were repeated at 10 and 20 min after an intramuscular injection of hyoscine butylbromide. Parametric maps were generated representing the mean change in signal amplitude (MSA) per voxel for each dynamic acquisition. Two observers independently assessed thresholding for optimal segmentation of small bowel from other sources of signal. Total voxel activity (TVA) for each study was calculated as a sum of MSA per slice and whole examination and TVA profiles were generated.

RESULTS

Independent observations suggest that the automated segmentation method described usefully segments small bowel activity from other signal. Small bowel movement represented as TVA varied three-fold in the five volunteers and was inhibited by anti-muscarinic injection.

CONCLUSION

It is possible to develop a new measure, based on automated segmentation of mean signal amplitude changes, of small bowel peristalsis using dynamic MR.

Ultrasonography of small intestinal obstructions: a contemporary approach

OBJECTIVES

To assess the accuracy of intestinal ultrasound for diagnosis of intestinal obstruction in dogs and cats.

METHODS

A prospective clinical study was performed. Inclusion criteria were dogs and cats with clinical signs suggestive of gastrointestinal obstruction. Animals with no obstruction detected on ultrasound were excluded if they could not be monitored for 48 hours to confirm absence of obstruction. Sonographic diagnosis of small intestinal obstruction was based on identification of at least two findings suggestive of intestinal obstruction.

RESULTS

Ninety-two patients suspected of having intestinal obstruction were included. Correct diagnosis of intestinal obstruction was made in 21 cases (23%), and in 68 (74%) this diagnosis was excluded. Interpretation of the images on prospective analysis had sensitivity, positive predictive, specificity and negative predictive values of 100%, 87.5%, 95.8% and 100%, respectively.

CLINICAL SIGNIFICANCE

Ultrasonography is an excellent method for investigation of animals with gastrointestinal disorders, and is particularly useful for excluding obstructive processes.

CT diagnosis of the nature of bowel obstruction: morphological evaluation of the transition point

PURPOSE

This study evaluated transition-point morphology for defining the nature of bowel obstructions.

MATERIALS AND METHODS

Computed tomography (CT) examinations of 95 patients affected by severe bowel obstruction (23 neoplastic, 72 nonneoplastic) were retrospectively reviewed.

RESULTS

The transition point was identified in 89 patients (94%); morphology in relation to the proximal loop was concave in 64 cases (68%), linear in five (5%) and convex in 20 (21%). Concave transition-point morphology was indicative of a nonneoplastic condition, with sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and diagnostic accuracy values of 89%, 100%, 100%, 74% and 92%, respectively. A linear shape had almost identical incidence among neoplastic (60%) and nonneoplastic (40%) conditions. A convex appearance correlated with neoplastic disease with sensitivity, specificity, PPV, NPV and diagnostic accuracy values of 87%, 100%, 100%, 96% and 97%, respectively.

CONCLUSIONS

In the case of bowel obstruction, transitionpoint detection indicates the obstruction site, whereas its morphological evaluation can contribute to defining the nature of the obstruction. A concave morphology indicates a nonneoplastic condition with a high probability; a convex morphology correlates with neoplastic disease, whereas linearity is not significant.