Computed Tomography of Small Bowel Obstruction

Towards an EKG for SBO: A Neural Network for Detection and Characterization of Bowel Obstruction on CT

A neural network was developed to detect and characterize bowel obstruction, a common cause of acute abdominal pain. In this retrospective study, 202 CT scans of 165 patients with bowel obstruction from March to June 2022 were included and partitioned into training and test data sets. A multi-channel neural network was trained to segment the gastrointestinal tract, and to predict the diameter and the longitudinal position ("longitude") along the gastrointestinal tract using a novel embedding. Its performance was compared to manual segmentations using the Dice score, and to manual measurements of the diameter and longitude using intraclass correlation coefficients (ICC). ROC curves as well as sensitivity and specificity were calculated for diameters above a clinical threshold for obstruction, and for longitudes corresponding to small bowel. In the test data set, Dice score for segmentation of the gastrointestinal tract was 78 ± 8%. ICC between measured and predicted diameters was 0.72, indicating moderate agreement. ICC between measured and predicted longitude was 0.85, indicating good agreement. AUROC was 0.90 for detection of dilated bowel, and was 0.95 and 0.90 for differentiation of the proximal and distal gastrointestinal tract respectively. Overall sensitivity and specificity for dilated small bowel were 0.83 and 0.90. Since obstruction is diagnosed based on the diameter and longitude of the bowel, this neural network and embedding may enable detection and characterization of this important disease on CT.

The target sign: a significant CT sign for predicting small-bowel ischemia and necrosis

OBJECTIVE

To investigate the correlation between changes in the thickness and density of diseased small-bowel wall and small-bowel ischemia and necrosis (SBN) on CT imaging when small-bowel obstruction (SBO) occurs.

METHODS

We retrospectively analyzed 186 patients with SBO in our hospital from March 2020 to June 2023. The patients were divided into simple SBO (control group) and SBN (case group) groups. We used logistic regression analysis, the chi-square test, and Fisher's exact test to analyze the correlation between the changes in the thickness and density of the diseased intestinal wall and the SBN. A receiver operating characteristic (ROC) curve was used to calculate the accuracy of the multivariate analysis.

RESULTS

Of the 186 patients with SBO, 98 (52.7%) had simple SBO, 88 (47.3%) had SBN, and the rate of SBN was 47.3% (88/186). Multivariate regression analysis revealed that six CT findings were significantly correlated with SBN (p < 0.05), namely, thickening of the diseased intestinal wall with the target sign (OR = 21.615), thinning of the diseased intestinal wall (OR = 48.106), increase in the diseased intestinal wall density (OR = 13.696), mesenteric effusion (OR = 21.635), decrease in the diseased intestinal wall enhancement on enhanced scanning (OR = 41.662), and increase in the diseased intestinal wall enhancement on enhanced scanning (OR = 15.488). The AUC of the multivariate analysis reached 0.987 (95% CI 0.974-0.999). Specifically, the target sign was easily recognizable on CT images and was a significant CT finding for predicting SBN.

CONCLUSION

We identified 6 CT findings that were significantly associated with SBN, and may be helpful for clinical treatment.

Adhesive Small Bowel Obstruction: A Review

Adhesion is a leading cause of small bowel obstruction. Adhesive small bowel obstruction has significant challenges in diagnosis, treatment and prevention with considerable impact on morbidity and socioeconomic burden. Small bowel obstruction caused by adhesion or any other aetiology is clinically indistinguishable due to similar clinical presentation. Computed Tomography scans and water-soluble contrast studies are more specific in diagnosis and possess value in predicting the need for surgery. Surgical management is indicated only in complicated cases or failed conservative treatments with the majority resolving with non-operative management. However, there is no clear-cut consensus about the timing of operative intervention. Meticulous surgical practice is the keystone in preventing adhesion formation despite the availability of numerous pharmacological and surgical strategies. This review aims to update the current knowledge of the pathophysiology of adhesion formation, treatment options and various prevention modalities of adhesive small bowel obstruction.

KEYWORDS

diagnosis; laparotomy; prevention; surgery.

Bowel obstruction: signs indicating the need for urgent surgery

Bowel obstruction is common in emergency departments. Obstruction is more common in the small bowel than in the large bowel. The most common cause is postsurgical adhesions. Nowadays, bowel obstruction is diagnosed with multidetector computed tomography (MDCT). MDCT studies for suspected bowel obstruction should focus on four points that need to be mentioned in the report: confirming the obstruction, determining whether there is a single transition point or whether the obstruction is found in a closed loop, establishing the cause of the obstruction, and seeking signs of complications. Identifying signs of ischemia is important in the management of the patient because it enables patients at higher risk of poor outcomes after conservation treatment who could benefit from early surgical intervention to avoid greater morbidity and mortality associated with strangulation and ischemia of the obstructed bowel loop.

Interpretation discrepancies of abdominal imaging by on-call radiology residents: Evaluation of risk factors

The aim of this study was to determine the rate, important findings, and risk factors related to discrepancies between on-call residents’ and attending radiologists’ interpretations of abdominal examinations. We identified 1132 eligible patients with abdominal radiology findings that were preliminary interpreted by on-call residents between February 2016 and September 2019. The preliminary interpretations were compared with the final interpretations by abdominal attending radiologists, including clinical data. The preliminary interpretations were analyzed by three radiologists in consensus, who categorized the reports according to organs, important findings (i.e., active bleeding, bowel obstruction, organ ischemia or infarction, and organ rupture), clinical outcomes, and discrepancies with respect to final interpretations. Multiple logistic regression analysis was used to evaluate the risk factors for important discrepant findings. Of 1132 patients, the bowel (n = 567, 50.1%) was the most common organ interpreted by on-call residents, followed by gallbladder/bile duct/pancreas (n = 139, 12.3%) and liver (n = 116, 10.2%). Of 1132, 359 patients (31.7%) had disease with 379 important findings: active bleeding (n = 222), organ rupture (n = 77), bowel obstruction (n = 52), bowel ischemia (n = 24), and organ infarction (n = 4). Sixty-four patients (5.6%) showed discrepancies, and 30 (2.6%) showed 32 important discrepant findings comprising 14 active bleeding, 10 bowel obstructions, 6 organ ruptures, and 2 cases of bowel ischemia. Of the 64 discrepant patients, 33 underwent delayed surgery (n = 18, 28.1%) or interventional treatment (n = 15, 23.4%). In multivariable analysis, bowel obstruction (adjusted odds ratio, 2.52; p = 0.049) was an independent risk factor for determining discrepancy between preliminary and final interpretations. The rate of overall and important discrepancies between on-call residents’ and final interpretations was low. However, given that the bowel was the most frequently interpreted organ, bowel obstruction was identified as a risk factor for discrepant interpretations. The identified risk factor and findings may be useful for residents to minimize discrepancies.

CT Imaging Findings in Patients with Ovarian Cancer and Acute Abdominal Symptoms: Experience at a Tertiary Cancer Center

PURPOSE

To evaluate computed tomography (CT) findings in patients with ovarian cancer presenting to a comprehensive cancer center's urgent care unit with acute abdominal symptoms.

METHODS

This retrospective study included consecutive patients with ovarian cancer who underwent abdominal CT at a comprehensive cancer center's urgent care unit between January 1, 2018, and January 14, 2020, due to acute abdominal symptoms. Two abdominal radiologists reviewed the abdominal CT reports, categorizing imaging findings as follows: (a) no new or acute finding, (b) new or increased bowel or gastric obstruction, (c) new or increased ascites, (d) new or increased peritoneal carcinomatosis, (e) new or increased nonperitoneal metastases, (f) new inflammatory or infectious changes, (g) new or increased hydronephrosis, (h) new or increased biliary dilatation, (i) new vascular complications, or (j) new bowel perforation.

RESULTS

A total of 200 patients (mean age, 59 years; range, 22-87) underwent a total of 259 abdominal CT scans, of which 217/259 (83.8%) scans were found to have new or increased findings. A total of 115/259 (44.4%) scans had only one finding while 102/259 (39.4%) scans had 2 or more findings. Altogether, 382 new or increased findings were detected: findings were most commonly related to bowel or gastric obstruction (92/382, 24.1%) with small bowel obstruction being the most common finding (80/382, 20.9%); ascites (78/382, 20.4%); peritoneal carcinomatosis (62/382, 16.2%); and nonperitoneal metastases (62/382, 16.2%). Inflammatory or infectious findings accounted for 30/382 (7.9%) findings.

CONCLUSION

Most patients with ovarian cancer presenting with acute abdominal had relevant positive findings on abdominal CT, with small bowel obstruction being the most common finding.

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.

Computed Tomography in Emergency Diagnosis and Management Considerations of Small Bowel Obstruction for Surgical vs. Non-surgical Approach

BACKGROUND

Small bowel obstruction (SBO) accounts for 15% of abdominal pain complaints referred to emergency departments and imposes significant financial burdens on the healthcare system. The absence of passage of flatus or stool and abdominal distention are reported as the most common symptom and a sign of SBO, respectively. Patients who do not demonstrate severe clinical or imaging findings are typically treated with conservative approaches. Patients with clinical signs of sepsis or physical findings of peritonitis are often instantly transferred to the operating room without supplementary imaging assessment. However, in cases where symptoms are non-specific, or the physical examination is challenging, such as in cases with loss of consciousness, the diagnosis can be complicated. This paper discusses the key findings detectable on Computed tomography (CT), which are vital for the emergent triage, proper treatment, and decision making in patients with speculated SBO.

METHOD

Narrative review of the literature.

RESULTS AND CONCLUSION

CT plays a key role in emergent triage, proper treatment, and decision making. It provides high sensitivity, specificity, and accuracy in the detection of early-stage obstruction and acute intestinal vascular compromise. It can also differentiate between various etiologies of this entity which is considered an important criterion in the triage of patients into surgical vs. non-surgical treatment. There are multiple CT findings, such as mesenteric edema, lack of the small-bowel feces, bowel wall thickening, fat stranding in the mesentery, and intraperitoneal fluid, which are predictive of urgent surgical exploration.

Imaging Modalities for Evaluation of Intestinal Obstruction

It is essential for the colon and rectal surgeon to understand the evaluation and management of patients with both small and large bowel obstructions. Computed tomography is usually the most appropriate and accurate diagnostic imaging modality for most suspected bowel obstructions. Additional commonly used imaging modalities include plain radiographs and contrast imaging/fluoroscopy, while less commonly utilized imaging modalities include ultrasonography and magnetic resonance imaging. Regardless of the imaging modality used, interpretation of imaging should involve a systematic, methodological approach to ensure diagnostic accuracy.

Acute small bowel obstruction: one-year retrospective study of admissions to inner city Royal Perth Hospital

BACKGROUND

Analyse admissions to Royal Perth Hospital (RPH) with acute small bowel obstruction (SBO), and identify trends between outcomes and management.

METHODS

Retrospective, single-centre review of patients admitted to RPH with acute SBO, between May 2017 and May 2018.

RESULTS

A total of 251 admissions met inclusion criteria. Increasing age correlated with increasing total length of stay (LOS) (r = 0.134, P = 0.033) and post-operative LOS (r = 0.349, P < 0.0001). Increasing age led to poorer outcomes (P < 0.0001). Diagnoses were most commonly adhesions (167/251 = 66.5%), hernias (47/251 = 18.7%) and inflammatory bowel diseases (11/251 = 4.4%). Operation rate for adhesional SBO was 24.6% (41/167) and non-adhesional SBO 54.8% (46/84). Median total LOS for operative versus conservative management was 9 days (interquartile range (IQR) 8) versus 3 days (IQR 3) (P < 0.0001). Median time to surgery was 1 day (IQR 2). Increased time from admission to theatre led to increasing post-operative LOS (r = 0.398, P = 0.0013). Median post-operative LOS for bowel resection versus no resection was 9 days (IQR 4.5) versus 6 days (IQR 4) (P = 0.0128). Of 101, 81 (80.2%) adhesional SBO resolved non-operatively after receiving Gastrografin, compared to 45 of 66 (68.2%) of those who did not (P = 0.07). It did not significantly alter total or post-operative LOS (P = 0.65 and P = 0.96), patient outcome (P = 0.26), or need for bowel resection (P = 0.63).

CONCLUSIONS

Operative management, bowel resection, older age and increasing time from admission to surgery increase LOS. Trial of Gastrografin in non-operative management of adhesion type small bowel obstructions does not significantly affect outcomes but tends to reduce operative rates.

Imaging of acute abdomen in cancer patients

The pattern of disease causing acute abdominal pain has changed over last few decades, some of this has been attributed to intraabdominal cancers. The most common acute abdominal complaints in cancer patients are related to the gastrointestinal system. Abdominal emergencies in cancer patients can result from the underlying malignancy itself, cancer therapy and/or result from the standard pathologies causing acute abdomen in otherwise healthy population. Therapy-related or disease-related immunosuppression or high dose analgesics often blunt many of the findings which are usually expected in non-cancer general population. This complicates the clinical picture rendering the clinical exam less reliable in many cancer patients, and resulting in different pathologies which clinicians and the radiologists should remain aware of. This article focuses on imaging illustrations with differential diagnosis for various emergency scenarios related to acute abdomen specifically in oncologic settings.

Small Bowel Obstruction: the Sun Also Rises?

Small bowel obstruction (SBO) remains a common reason for emergency/unplanned admissions, and remains a significant burden to SBO patients and the healthcare system alike. The management of SBO has undergone a significant paradigm shift over the years, shifting far from the tenet to "never let the sun rise on a bowel obstruction." Not only has the timing to surgery changed, but there is also an increased utilization of diagnostic tools to aid clinical decision-making. Furthermore, the surgical management is beginning to favor a less invasive approach. This review will serve to provide an up-to-date review of the evaluation and management of SBO, based on the most recent available evidence and our experience with the methods described.

Accuracy of Computed Tomography in Small Bowel Obstruction

Small bowel obstruction is a common clinical occurrence, primarily caused by adhesions. The diagnosis is usually made on the clinical findings and the presence of dilated bowel loops on plain abdominal radiograph. Computed tomography (CT) is increasingly used to diagnose the cause and location of the obstruction to aid in the timing of surgical intervention. We used a retrospective chart review to identify patients with a diagnosis of small bowel obstruction between 2009 and 2012. We compared the findings on CT with the findings at operative intervention. Sixty patients had abdominal CT and subsequent surgical intervention. Eighty-three per cent of CTs were correct for small intestine involvement and 80 per cent for colon involvement. The presence of adhesions or perforation was correctly identified in 21 and 50 per cent, respectively. Sixty-four per cent correctly identified a transition point. The presence of a mass was correctly identified in 69 per cent. Twenty per cent of the patients who had ischemic small bowel at surgery were identified on CT. CT has a role in the clinical assessment of patients with small bowel obstruction, identifying with reasonable accuracy the extent of bowel involvement and the presence of masses and transition points. It is less reliable at identifying adhesions, perforations, or ischemic bowel.

Internal hernia strangulated on appendicular tourniquet: a case report of an exceptional anomaly of the appendix revealed by a rare hernia

BACKGROUND

Internal hernias and the appendicular tourniquet are two rare pathologies.

CASE PRESENTATION

We report here a case of a 68-year-old obese patient, who has acute small bowel obstruction due to strangulated internal hernia through an appendicular tourniquet. This appendicular tourniquet results from the adhesion between the tip of the appendix and its body. This obstruction was complicated by plugged perforation. Resection of the small bowel segment was performed, in addition to appendectomy, lavage, and drainage. The postoperative recovery was uneventful.

CONCLUSION

Acute bowel obstruction secondary to strangulation of an internal hernia through an appendicular tourniquet is exceptional.

[Minimally invasive treatment of rare forms of mechanical intestinal obstruction]

AIM

To develop medical algorithms for reduction of morbidity and mortality in rare forms of mechanical intestinal obstruction.

MATERIAL AND METHODS

17 patients with mechanical intestinal obstruction have been operated in Sklifosovsky Research Institute for Emergency Care for the period 2010 - 2016. There were 13 women and 4 men aged 56 (44,5-74,5) years on the average. Phytobezoar was detected in 7 patients (41.2%), tumor in 7 patients (41.2%) and gallstone ileus in 3 patients (17.6%).

RESULTS

There were no complications in group 1. In group 2 postoperative complications occurred in 3 patients: gastrocnemius vein thrombosis followed by successful medication (Clavien-Dindo type II), abdominal abscess drained under ultrasonic control (Clavien-Dindo type IIIa) and 1 (8.3%) death (Clavien-Dindo type V). Postoperative mortality in group 2 was 8.3%.

CONCLUSION

Despite small sample size and no statistically reliable results the advantages of minimally invasive access are obvious. However, further trials are required to ensure the reliability of the results.

Small Bowel Obstruction

Identifying patients with small bowel obstruction who need operative intervention and those who will fail nonoperative management is a challenge. Without indications for urgent intervention, a computed tomography scan with/without intravenous contrast should be obtained to identify location, grade, and etiology of the obstruction. Most small bowel obstructions resolve with nonoperative management. Open and laparoscopic operative management are acceptable approaches. Malnutrition needs to be identified early and managed, especially if the patient is to undergo operative management. Confounding conditions include age greater than 65, post Roux-en-Y gastric bypass, inflammatory bowel disease, malignancy, virgin abdomen, pregnancy, hernia, and early postoperative state.

Managing Adhesive Small Bowel Obstruction with Water-Soluble Contrast Should Be Protocolized: A Retrospective Analysis

Aim  Current literature emphasizes the effectiveness of computed tomography (CT) and water-soluble contrast agent, Gastrografin, in the investigation of adhesive small bowel obstruction (ASBO). As there is no management protocol for ASBO at our institution, the aim of this study was to determine the effect of imaging methods—CT, Gastrografin challenge (GC), or plain-film X-ray—on patient outcomes in a clinical setting.

Methods  All 163 emergency presentations of ASBO during the study period between December 2010 and September 2012 were collected retrospectively. Cases were divided into three groups: CT with oral contrast, GC, or plain-film X-ray only. The primary outcome was time to theater.

Results  Patients investigated with X-ray only were significantly less likely to require surgery (6% in plain-film X-ray vs. 35% and 20% in CT and GC, respectively; p  = 0.003). In cases requiring surgery, GC was associated with a 24-hour longer time to imaging than CT ( p  < 0.001). The time to theater was 71:25 hours for GC versus 46:39 for CT ( p  = 0.039). There was no significant difference in bowel resection or complication rates.

Conclusion  Patients undergoing water-soluble contrast studies were subjected to unnecessary delays in their clinical course. These delays are costly and avoidable. The development and implementation of an evidence-based protocol for the management of small bowel obstruction is strongly recommended. The lack of a protocol likely caused significant delays in Gastrografin administration, reducing its known benefits for clinical decision-making and length of stay.

High-Density Free Fluid on Computed Tomography: a Predictor of Surgical Intervention in Patients with Adhesive Small Bowel Obstruction

BACKGROUND

Patients with adhesive small bowel obstruction (ASBO) often develop intraabdominal free fluid (IFF). While IFF is a finding on abdominopelvic computed tomography (CT) associated with the need for surgical intervention, many patients with IFF can be still managed non-operatively. A previous study suggested that a higher red blood cell count of IFF is highly predictive of strangulated ASBO. We hypothesized that radiodensity in IFF (Hounsfield unit (HU)) on CT would predict the need for surgical intervention.

STUDY DESIGN

Patients with clinicoradiological evidence of ASBO between January 2009 and December 2013 were identified. In patients with IFF > 3 cm² identified on CT, the HU was measured in the largest pocket of IFF. A sensitivity analysis was performed to determine a high-density HU threshold. The HU of patients who underwent therapeutic laparotomy was compared with those successfully discharged with non-operative management.

RESULTS

A total of 318 patients with ASBO (median age 52 years, 56.0 % male) were identified. Of 111 patients who had IFF on CT, 55.9 % underwent therapeutic laparotomy and 15.3 % required bowel resection. Radiodensity of IFF in the operative group was significantly higher than that in the non-operative group (18.2 vs. 7.0 HU, p < 0.01). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of high-density IFF (>10 HU) to predict the need for surgical intervention were 83.9, 65.3, 75.4, 76.2, and 75.6 %, respectively.

CONCLUSIONS

High-density IFF on CT was significantly associated with the need for surgical intervention in patients with ASBO. Prospective study to validate the predictive value of high-density IFF on CT will be warranted.

Cancer therapy-related complications in the bowel and mesentery: an imaging perspective

Cancer therapy-induced complications in the bowel and mesentery are fairly common. It is important for clinicians to be aware of these complications and the agents most frequently implicated. Cancer therapy is rapidly evolving and often encompasses both classic cytotoxic drugs and newer molecular targeted agents. Drugs from both broad classes can have numerous adverse effects on the bowel and mesentery that can be detected on imaging. These adverse effects include ileus, various forms of enterocolitis, gastrointestinal perforation, pneumatosis intestinalis, secretory diarrhea, and sclerosing mesenteritis. These complications are diverse and range from relatively benign to life threatening. The management is also variable, but many of these conditions are easily controlled and reversed with supportive care and cessation of the particular cancer therapy. The objective of this pictorial essay is to demonstrate some of the more common cancer therapy-induced complications of the bowel and mesentery, with a focus on the radiographic findings.

MDCT findings in small bowel obstruction: implications of the cause and presence of complications on treatment decisions

Small bowel obstruction (SBO) accounts for a considerable proportion of emergency room visits, inpatient admissions, and surgical interventions in the United States. Multi-detector computed tomography (MDCT) plays a key role in imaging patients presenting with acute symptoms suggestive of SBO, which helps in establishing the diagnosis, elucidating the cause of obstruction, and detecting complications, such as ischemia or frank bowel necrosis and perforation. Recently, management of patients with SBO has shifted toward a more conservative approach with supportive care and nasogastric tube decompression, as the obstruction in many cases can resolve spontaneously without the need for operative intervention. However, management decisions in SBO remain notoriously difficult, relying on a combination of clinical, laboratory, and imaging factors to help stratify patients into conservative or surgical treatment. Imaging is often an important factor assisting in the decision-making process since traditional clinical signs of vascular compromise, such as acidosis, fever, leukocytosis, and tachycardia are often unreliable in predicting the need for operative intervention. Thus, it is critically important for radiologists to identify imaging features that suggest or indicated high likelihood of bowel vascular compromise in order to help optimize management prior to the development of bowel ischemia and eventually necrosis. By excluding signs of potentially ischemic or necrotic bowel on MDCT, patients may be spared unnecessary surgery, thus decreasing postsurgical complications and averting potential increase for the risk of future SBO and repeated surgery. Conversely, if imaging features indicate potential vascular compromise of the bowel wall that may lead to bowel ischemia, urgent surgical intervention may prevent progression to bowel necrosis and subsequent perforation.

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.

Evaluating Patients with Left Upper Quadrant Pain

Imaging plays a major role in the evaluation of patients who present to the emergency department with acute left upper quadrant (LUQ) pain. Multidetector computed tomography is currently the primary modality used for imaging these patients. The peritoneal reflections, subperitoneal compartment, and peritoneal spaces of the LUQ are key anatomic features in understanding the imaging appearance of acute diseases in this area. Diseases of the stomach, spleen, pancreas, and splenic flexure are encountered in patients with acute LUQ pain. Optimization of the imaging protocol is vital for accurate diagnosis and characterization of these diseases in the acute setting.

Bowel Obstruction

Small bowel obstruction and large bowel obstruction account for approximately 20% of cases of acute abdominal surgical conditions. The role of the radiologist is to answer several key questions: Is obstruction present? What is the level of the obstruction? What is the cause of the obstruction? What is the severity of the obstruction? Is the obstruction simple or closed loop? Is strangulation, ischemia, or perforation present? In this presentation, the radiologic approach to and imaging findings of patients with known or suspected bowel obstruction are presented.

Small bowel obstruction: A practical step-by-step evidence-based approach to evaluation, decision making, and management

The initial goal of evaluating a patient with SBO is to immediately identify strangulation and need for urgent operative intervention, concurrent with rapid resuscitation. This relies on a combination of traditional clinical signs and CT findings. In patients without signs of strangulation, a protocol for administration of Gastrografin immediately in the emergency department efficiently sorts patients into those who will resolve their obstructions and those who will fail nonoperative management.Furthermore, because of the unique ability of Gastrografin to draw water into the bowel lumen, it expedites resolution of partial obstructions, shortening time to removal of nasogastric tube liberalization of diet, and discharge from the hospital. Implementation of such a protocol is a complex, multidisciplinary, and time-consuming endeavor. As such, we cannot over emphasize the importance of clear, open communication with everyone involved.If surgical management is warranted, we encourage an initial laparoscopic approach with open access. Even if this results in immediate conversion to laparotomy after assessment of the intra-abdominal status, we encourage this approach with a goal of 30% conversion rate or higher. This will attest that patients will have been given the highest likelihood of a successful laparoscopic LOA.

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.

Imaging acute complications in cancer patients: what should be evaluated in the emergency setting?

Increased incidence world-wide of cancer and increased survival has also resulted in physicians seeing more complications in patients with cancer. In many cases, complications are the first manifestations of the disease. They may be insidious and develop over a period of months, or acute and manifest within minutes to days. Imaging examinations play an essential role in evaluating cancer and its complications. Plain radiography and ultrasonography (US) are generally performed initially in an urgent situation due to their wide availability, low cost, and minimal or no radiation exposure. However, depending on a patient's symptoms, evaluation with cross-sectional imaging methods such as computed tomography (CT) and magnetic resonance imaging (MRI) is often necessary. In this review article, we discuss some of the most important acute noninfectious oncological complications for which imaging methods play an essential role in diagnosis.

ASER core curriculum illustration project-volvulus: a rare cause of small bowel obstruction

This is the ninth installment of a series that will highlight one case per publication issue from the bank of cases available online as part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for Study online at http://www.aseronline.org/curriculum/toc.htm .