Radiology of small bowel obstruction: contemporary approach and controversies

Current abdominal X-rays practice in accident and emergency

INTRODUCTION

Previous literature reviews revealed that abdominal X-rays (AXR) performed for the accident and emergency department (A&E), had low sensitivity, high further imaging and non-alignment rate to the Royal College of Radiologists (RCR) guidelines. A study was performed to investigate the current practice with the aim of making recommendations to improve practice, which can reduce patients' radiation exposures, while can re-routing resources to other priorities.

METHODS

A study was performed in one of the UK's largest A&Es, in accordance with the RCR guidelines. All the AXR requests from A&E, regardless of the patient's age, within a 28-day period, were retrospectively assessed. Non-A&E patients and abandoned examinations due to uncooperative patients were excluded. The total number of AXR requests received by the A&E imaging department was 169, with 28/169 falling into the exclusion criteria.

RESULTS

Of the 141 included requests, five unjustified requests were correctly rejected. The remaining 136 requests were accepted and performed, though only 115/136 (84.6%) of these were justified. The most common justified and unjustified indications were obstruction and renal stones, respectively. Only 4% of reported AXR had pathological abnormalities, while 45/136 patients had further imaging.

CONCLUSIONS

The small proportion of significant findings echoed previous studies, suggesting an AXR overuse. Over 80% of non-compliant requests were performed, and awareness of the justification guidelines can be increased by clinical governance, posters, or an algorithm previously presented. The 32.4% further imaging rate recorded in this study, as opposed to the 73.7% reported in previous literature, merits attention.

IMPLICATIONS TO PRACTICE

Stopping the overuse of AXR can minimise the radiation dose received and relieve the mounting pressure in imaging and reporting, which can serve other patients who would benefit from the services otherwise.

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.

Use of the Water-Soluble Contrast Medium Gastrografin in Treatment of Adhesive Small Bowel Obstruction in Patients with and Without Chronic Radiation Enteropathy: A Single-Center Retrospective Study

Background

This retrospective cohort study from a single center aimed to compare patient outcomes following the use of the water-soluble contrast medium Gastrografin in the treatment of adhesive small bowel obstruction (ASBO) in patients with and without a history of chronic radiation enteropathy (CRE).

Material/Methods

Fifty-nine patients with CRE-induced small bowel obstruction (SBO) and 53 patients with ASBO at Jinling Hospital between April 2014 and February 2018 were enrolled. The patients were given 100 ml Gastrografin through a naso-jejunal tube, and erect abdominal X-rays were taken. Risk factors were found to be correlated with successful non-operative management (SNM) through statistical analyses.

Results

The success rate of conservative treatment was higher in the Gastrografin group than in the control group (P<0.05). The Gastrografin challenge test is predictive of need for surgery in CRE-induced SBO and ASBO (AUC=0.860 and 0.749, respectively). The predictors associated with SNM in the CRE-induced SBO group were the total dose of radiotherapy, the Gastrografin challenge test, and previous operations for SBO. In the ASBO group, the predictors were the Gastrografin challenge test and previous operations for SBO. The operation rate of SBO patients with Gastrografin treatment was significantly lower than that in the control group (P<0.05).

Conclusions

The findings from this study showed that the use of Gastrografin effectively resolved ASBO in patients with and without a history of CRE, but a long-term requirement for surgery could not be avoided. The Gastrografin challenge may be a useful test to predict surgical outcomes.

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.

Current management of adhesive small bowel obstruction

Small bowel obstruction is a common and significant surgical presentation. Approximately 30% of presentations will require surgery during admission. The great challenge of adhesive small bowel obstruction (ASBO) management is the early detection of silent intestinal ischaemia in patients initially deemed suitable for conservative therapy. Recent literature emphasizes the effectiveness of computed tomography enterography and water-soluble contrast studies in the management of ASBO. Low-volume undiluted water-soluble contrast has been shown to have both triage and therapeutic value in the management of ASBO. Their use has been demonstrated to reduce the need for surgery to below 20%. There has also been growing interest in clinicoradiological algorithms which aim to predict ischaemia early in the course of presentation. The aim of this review is to summarize the latest evidence and clarify previous uncertainties, specifically regarding the duration of conservative treatment, timing of contrast studies and the reliability of predictive algorithms. Based on this latest evidence, we have formulated a management protocol which aims to integrate these latest developments and formalize a strategy for best management in ASBO.

Accuracy of abdominal ultrasound for the diagnosis of small bowel obstruction in the emergency department

BACKGROUND

Emergency physicians frequently encounter patients with acute small bowel obstructions (SBO). Although computed tomography (CT) imaging is the current gold standard in the assessment of patients with suspected SBO in the emergency department, a few studies have examined the use of ultrasound as an alternative imaging technique.

METHODS

We evaluated the accuracy of ultrasound performed in the ED by a variety of providers (physicians with various levels of training, physician assistants) compared to CT imaging in 47 patients with suspected SBOs.

RESULTS

Our data demonstrated a sensitivity of 93.8% and a specificity of 93.3% when compared to abdominal CT, and a sensitivity of 94.3% and specificity of 95.2% using a composite endpoint of abdominal CT and discharge diagnosis.

CONCLUSION

Ultrasound can play an important role in the identification of small bowel obstructions in ED patients.

Computed tomography features associated with operative management for nonstrangulating small bowel obstruction

BACKGROUND

The management of nonstrangulating small bowel obstruction (SBO) may require surgery, but the need for and timing of surgical intervention isn't always apparent. We sought to determine whether specific features on computed tomography (CT) can predict the necessity for operative management.

METHODS

Two radiologists independently reviewed CT scans from all patients admitted to hospital with SBO between 2004 and 2006. We examined the association between radiographic features and operative management by univariate analysis using the χ(2) or Fisher exact test. Significant factors with high concordance between radiologists were entered into a multivariable stepwise logistic regression model.

RESULTS

There were 228 patients with SBO, 63 of whom met our inclusion criteria and had CT scans available for review. Three CT features were frequently associated with operative management and had good concordance between radiologists: complete bowel obstruction, small bowel dilation greater than 4 cm and transition point. Transition point was the only significant factor predictive of operative management for SBO on multivariable logistic regression analysis (OR 19, 95% confidence interval 1.8-201, p = 0.014).

CONCLUSION

In patients with nonstrangulating SBO, the presence of a transition point on CT scan should alert the surgeon to the increased likelihood that operative management may be required.

The role of interleukin 17 in Crohn's disease-associated intestinal fibrosis

Background

Interleukin (IL)-17A and IL-17E (also known as IL-25) have been implicated in fibrosis in various tissues. However, the role of these cytokines in the development of intestinal strictures in Crohn’s disease (CD) has not been explored. We investigated the levels of IL-17A and IL-17E and their receptors in CD strictured and non-strictured gut, and the effects of IL-17A and IL-17E on CD myofibroblasts.

Results

IL-17A was significantly overexpressed in strictured compared with non-strictured CD tissues, whereas no significant difference was found in the expression of IL-17E or IL-17A and IL-17E receptors (IL-17RC and IL-17RB, respectively) in strictured and non-strictured CD areas. Strictured CD explants released significantly higher amounts of IL-17A than non-strictured explants, whereas no difference was found as for IL-17E, IL-6, or tumor necrosis factor-α production. IL-17A, but not IL-17E, significantly inhibited myofibroblast migration, and also significantly upregulated matrix metalloproteinase (MMP)-3, MMP-12, tissue inhibitor of metalloproteinase-1 and collagen production by myofibroblasts from strictured CD tissues.

Conclusions

Our results suggest that IL-17A, but not IL-17E, is pro-fibrotic in CD. Further studies are needed to clarify whether the therapeutic blockade of IL-17A through the anti-IL-17A monoclonal antibody secukinumab is able to counteract the fibrogenic process in CD.

"Venous cut-off sign" as an adjunct to the "whirl sign" in recognizing acute small bowel volvulus via CT scan

INTRODUCTION

A young adult patient was admitted for signs and symptoms of acute abdomen.

MATERIALS AND METHODS

Urgent CT scan was performed and small bowel volvulus was confirmed. The "whirl sign" diagnostic of small bowel volvulus was present.

RESULTS

Furthermore, the accompanying superior mesenteric vein was noted to be truncated at the point of torsion.

CONCLUSION

The "venous cut-off sign" can be a useful adjunct sign to the diagnosis.

The role of ultrasound in the management of intestinal obstruction

Intestinal obstruction (IO) is a common cause of acute abdominal pain. The recent increased use of sonography in the initial evaluation of abdominal pain has made point-of-care ultrasound a valuable tool for the diagnosis of IO. Sonography is as sensitive, but more specific, than plain abdominal X-ray in the diagnosis of IO. Point-of-care ultrasound can answer specific questions related to IO that assist the acute care physician in critical decision making. Sonography can also help in the resuscitation of patients by serial measurement of the IVC diameter. We review the sonographic findings of IO and the role of point-of-care ultrasound in the management of patients having IO.

A prospective randomized trial of transnasal ileus tube vs nasogastric tube for adhesive small bowel obstruction

AIM: To study the therapeutic efficacy of a new transnasal ileus tube advanced endoscopically for adhesive small bowel obstruction.

METHODS: A total of 186 patients with adhesive small bowel obstruction treated from September 2007 to February 2011 were enrolled into this prospective randomized controlled study. The endoscopically advanced new ileus tube was used for gastrointestinal decompression in 96 patients and ordinary nasogastric tube (NGT) was used in 90 patients. The therapeutic efficacy was compared between the two groups.

RESULTS: Compared with the NGT group, the ileus tube group experienced significantly shorter time for relief of clinical symptoms and improvement in the findings of abdominal radiograph (4.1 ± 2.3 d vs 8.5 ± 5.0 d) and laboratory tests (P < 0.01). The overall effectiveness rate was up to 89.6% in the ileus tube group and 46.7% in the NGT group (P < 0.01). And 10.4% of the patients in the ileus tube group and 53.3% of the NGT group underwent surgery. For recurrent adhesive bowel obstruction, ileus tube was also significantly more effective than NGT (95.8% vs 31.6%). In the ileus tube group, the drainage output on the first day and the length of hospital stay were significantly different depending on the treatment success or failure (P < 0.05). The abdominal radiographic improvement was correlated with whether or not the patient underwent surgery.

CONCLUSION: Ileus tube can be used for adhesive small bowel obstruction. Endoscopic placement of the ileus tube is convenient and worthy to be promoted despite the potential risks.

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.

Management of patients with malignant bowel obstruction and stage IV colorectal cancer

BACKGROUND

Malignant bowel obstruction (MBO), a serious problem in stage IV colorectal cancer (CRC) patients, remains poorly understood. Optimal management requires realistic assessment of treatment goals. This study's purpose is to characterize outcomes following palliative intervention for MBO in the setting of metastatic CRC.

STUDY DESIGN

Retrospective review of a prospective palliative database identified 141 patients undergoing surgical (OR; n = 96) or endoscopic (GI; n = 45) procedures for symptoms of MBO.

RESULTS

Median patient age was 58 years, median follow-up 7 months. Most (63%) had multiple sites of metastases. Computed tomography (CT) scan findings of carcinomatosis (p = 0.002), ascites (p = 0.05), and multifocal obstruction with carcinomatosis and ascites (p = 0.03) significantly predicted the need for percutaneous or open gastrostomy tube, or stoma. Procedure-associated morbidity for 81 patients with small bowel obstruction (SBO) was 37%; 7% developed an enterocutaneous fistula/anastomotic leak. Thirty-day mortality was 6%. Most (84%) patients were palliated successfully; some received additional chemotherapy (38%) or surgery (12%). Procedure-associated morbidity for 60 patients with large bowel obstruction (LBO) was 25%; 11 patients (18%) required other procedures for stent failure, with one death at 30 days. Symptom resolution was >97%. Patients with LBO had improved symptom resolution, shorter length of stay (LOS), and longer median survival than patients with SBO.

CONCLUSIONS

Patients with MBO and stage IV CRC were successfully palliated with GI or OR procedures. Patients with CT-identified ascites, carcinomatosis, or multifocal obstruction were least likely to benefit from OR procedures. CT plays an important role in preoperative planning. Sound clinical judgment and improved understanding are required for optimal management of MBO.

Abdominal pain in special populations

Evaluation and management of acute abdominal pain in special populations can be challenging for the emergency physician. This article focuses on two specific populations: patients with altered immunologic function and postprocedural patients. Recognition of life-threatening abdominal diseases may be delayed in immunosuppressed patients because of the atypical presentations of these conditions. In postprocedural patients, evaluation of acute abdominal symptoms requires an understanding of the complications of procedures often performed by others. The unique characteristics of abdominal pain in these two populations and, more specifically, which diseases to consider and how to use appropriate testing to detect life-threatening conditions, are discussed.

Prognostic value of MDCT in malignant large-bowel obstructions

PURPOSE

This study aimed to correlate multidetector-row computed tomography (MDCT) findings and postoperative prognosis in malignant large-bowel obstructions.

MATERIALS AND METHODS

Twenty-seven patients affected by malignant colonic obstruction underwent MDCT examination and were analysed for obstruction site, colon-wall morphology, intestinal content alterations and transverse diameter of ascending colon.

RESULTS

Obstruction site was recognised in all cases (5/27 ascending colon; 1/27 transverse colon; 11/27 descending colon; 10/27 sigma-rectum). Intestinal content consisted of mainly air in 3/27 patients, mainly fluid in 11/27 and air-fluid levels in 13/27. In 9/27 cases, pneumatosis intestinalis was found. Mean maximum diameter of the ascending colon was 8.2 cm. Overall mortality rate was 37%. An intestinal content mainly consisting of air (3/3 living patients) or fluid (7/11 living patients) were indicative of good prognosis. Air-fluid level detection indicated poor prognosis in 7/13 cases. Pneumatosis intestinalis (7/9 deceased patients) and ascending colon diameter values > or =10 cm (7/7 deceased patients) were indicative of poor prognosis.

CONCLUSIONS

MDCT can identify the presence and site of malignant large-bowel obstructions and may provide useful prognostic information.

CT enteroclysis in incomplete small bowel obstruction

The timing of surgical intervention as well as the optimal method of radiologic investigation for patients with incomplete, open loop small bowel obstruction has changed over the past two decades. This review focuses on the role of computed tomographic enteroclysis in the evaluation of patients with suspected small bowel obstruction. The technique of examination is described and an overview of its clinical applications and imaging controversy are presented.

Cancer emergencies: the acute abdomen

The most common complaints among patients with cancer who present to the emergency department are related to the gastrointestinal system, and 40% of these patients complain of abdominal pain. These presentations can stem from the underlying malignancy itself, treatment directed toward the disease, or the full range of pathologies present in a healthy population. Immunosuppression may blunt many of the findings one expects in a healthy population of patients, thus rendering the clinical exam less reliable in many patients with cancer. Moreover, the degree of immunosuppression shapes both the types of pathologies the clinician should consider and the rate at which the disease may progress. Understanding the limitations of physical examination, pathophysiology of disease, and the methods by which these diagnoses are established is of critical importance in this population. This article focuses specifically on patients with cancer who present with an acute abdomen, and it discusses how a concurrent malignancy can shape the differential diagnosis in these cases.

Clinical impacts of oral gastrografin follow-through in adhesive small bowel obstruction (SBO)

BACKGROUND

Many studies have shown that gastrografin can be used for diagnosis of adhesive small bowel obstruction (ASBO) and for assessing the need for surgical intervention. However, several studies have reported conflicting results. Therefore, the aim of this study is to assess the diagnostic and therapeutic effect of gastrografin in ASBO.

PATIENTS AND METHODS

Altogether, 110 patients with ASBO were randomized into control and gastrografin groups. In the gastrografin group, 100 mL of the dye was administered through a nasogastric tube. Obstruction was considered complete if the contrast failed to reach the colon on the 24-h film. Patients with gastrografin in the colon within 24 h after dye administration were considered as partially obstructed, and were submitted to nonoperative treatment. The patients were operated on if they developed signs of strangulation or failed to improve within 48 h.

RESULTS

The overall operative rate was 14.5% in gastrografin group versus 34.5% in control group, P=0.04. The time from admission to resolution of symptoms was significantly lower in gastrografin group (19.5 versus 42.6 h, P=0.001), and the length of hospital stay was shorter in gastrografin group (3.8 versus 6.9 d 0.002), and in nonoperative patients (3.1 versus 5.1 days). Sensitivity, specificity, positive predictive value, and negative predictive value for gastrografin follow-through as an indicator for operative treatment of ASBO were 87.5%, 100%, 100 % , and 97.9%, respectively.

CONCLUSIONS

Oral gastrografin helps in the management of ASBO. Oral gastrografin is safe and reduces the operative rate and time of resolution as well as hospital stay.

Ischemia and infarction of the intestine related to obstruction

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

CT enteroclysis in small bowel Crohn's disease

The diagnostic evaluation of small bowel Crohn's disease has changed dramatically over the last decade. The introduction of wireless capsule endoscopy, double balloon endoscopy and the introduction of newer therapeutic agents have changed the role of imaging in the small bowel. Additionally, advances in multidetector CT technology have further changed how radiologic investigations are utilized in the diagnosis and management of small bowel Crohn's disease. This article describes how we perform CT enteroclysis in the investigation of small bowel Crohn's disease and discusses the role of CT enteroclysis in the current management of small bowel Crohn's disease.

Gastrointestinal disorders in elderly patients

Gastrointestinal disorders are common in elderly patients, and the clinical presentation, complications, and management may differ from those in younger patient. Most impairment occurs in the proximal and distal tract of the gastrointestinal system. Swallowing abnormalities with a wide span of symptoms and pelvic floor pathologies involving all the pelvic compartments are common. Acute abdomen, often from small bowel obstruction or mesenteric ischemia, can pose a diagnostic challenge, because a mild clinical presentation may hide serious visceral involvement. In this setting, the radiologist often is asked to suggest the appropriate management options and to guide the management.

Mechanical obstruction of the small bowel and colon

Mechanical obstruction of the small bowel and colon is moderately common, accounting for several hundred thousand admissions per year in the United States. Patients generally present with abdominal pain, nausea and emesis, abdominal distention, and progressive obstipation. Clinical findings of high fever, localized severe abdominal tenderness, rebound tenderness, severe leukocytosis, or metabolic acidosis suggest possible complications of bowel necrosis, bowel perforation, or generalized peritonitis. Differentiation of total mechanical obstruction from partial mechanical obstruction and pseudo-obstruction is important because total mechanical obstruction is generally treated surgically,whereas the other two entities are usually treated medically. Mechanical obstruction is usually suggested by plain abdominal radiographs, and confirmed by small bowel follow through,abdominal CT, or CT enteroclysis.

Intestinal obstruction: trends in imaging utilization and their influence in its rising hospital bill

The purpose of the study was to evaluate trends in the utilization of different imaging modalities and review how imaging utilization practices affect hospital charges for patients with intestinal obstruction. All patients discharged with a primary diagnosis of intestinal obstruction during 6 fiscal years (1999-2004) were retrospectively studied. We obtained data on patients' demographics, procedures, outcomes, imaging services utilization, and hospital and imaging charges from our institution's transition system (a clinical and financial decision support software system). The institutional review board approved this study. Surgery was performed in 26% of patients in 1999 and in 40% in 2004 (p = 0.01) with the mortality rate significantly (p < 0.01) dropping from 3.8% to 0.4%. A total of 5,292 abdominal imaging studies were obtained; 93% of those were either abdominal radiographs or abdomino-pelvic computed tomography (CT) scans. CT studies per patient increased from 0.5 in 1999 to 1 in 2004 (p < 0.01), while abdominal radiographs (mean = 2.4) did not significantly change over the entire study period (p = 0.6). Average imaging charges doubled during the study period ($1,572 to $3,012, p < 0.01). Average hospital charges increased from $18,138 in 1999 to $32,808 in 2004 (p < 0.01). The fraction of hospital charges attributed to imaging varied between 8.7% and 9.2%. CT utilization for intestinal obstruction increased from 1999 to 2004 without modality substitution. While hospital and imaging charges have significantly increased, the fraction represented by imaging has remained constant, suggesting that imaging is an unlikely cause for the increase in hospital charges.

CT Enteroclysis

Computed tomographic (CT) enteroclysis is a hybrid technique that combines the methods of fluoroscopic intubation-infusion small-bowel examinations with that of abdominal CT. The use of multidetector CT technology has made this a versatile examination that has evolved into two distinct technical modifications. CT enteroclysis can be performed by using positive enteral contrast material without intravenous contrast material and neutral enteral contrast material with intravenous contrast material. CT enteroclysis has been shown to be superior to other imaging tests such as peroral small-bowel examinations, conventional CT, and barium enteroclysis, except in the demonstration of early apthous ulcers of Crohn disease. CT enteroclysis is complementary to capsule endoscopy in the elective investigation of small-bowel disease, with a specific role in the investigation of Crohn disease, small-bowel obstruction, and unexplained gastrointestinal bleeding.

CT enteroclysis: techniques and applications

CT enteroclysis overcomes the individual deficiencies of both barium enteroclysis and conventional CT and combines the advantages of both into one technique whose clinical applicability has been simplified and made more reliable with multidetector CT technology. This article examines the techniques of CT enteroclysis and presents an overview of its clinical applications relative to other methods of small bowel imaging.

Accuracy of abdominal radiography in acute small-bowel obstruction: does reviewer experience matter?

OBJECTIVE

The purposes of this study were to determine the accuracy of abdominal radiography in the detection of acute small-bowel obstruction (SBO), to assess the role of reviewer experience, and to evaluate individual radiographic signs of SBO.

MATERIALS AND METHODS

A retrospective study was performed in which the subjects were 90 patients with suspected SBO who underwent CT and abdominal radiography within 48 hours of each other. The patients were enrolled from June 1, 2003, to February 2004. Twenty-nine of the patients had proven SBO. Hard-copy radiographs were reviewed by three groups of radiologists: senior staff, junior staff, and second-year radiology residents. Each reviewer evaluated the quality of the radiographs, patient position for acquisition of the radiographs, and whether SBO was present. The reviewers rated their confidence on a five-point scale and recorded the presence or absence of specific radiographic signs of SBO. Chi-square tests were used to compare the three groups. A statistically significant finding was considered p < 0.05. Receiver operating characteristic (ROC) curves were fit with a 10-point confidence scale.

RESULTS

The sensitivity for SBO among the six reviewers ranged from 59% to 93%. The senior staff members were significantly more accurate. The mean sensitivity, specificity, and accuracy for all six reviewers were 82%, 83%, and 83%, respectively. Three radiographic signs were highly significant (p < 0.001): two or more air-fluid levels, air-fluid levels wider than 2.5 cm, and air-fluid levels differing more than 5 mm from one another in the same loop of small bowel. ROC analysis showed that senior staff is significantly more accurate than the other groups in the detection of acute SBO.

CONCLUSION

Our results confirmed that abdominal radiographs are accurate in the detection of acute SBO, that more-experienced radiologists are more accurate than less-experienced reviewers in the evaluation of abdominal radiographs, and that three types of air-fluid levels are highly predictive of the presence of SBO.

[Emergency radiology of bowel obstruction]

Clinical radiology is a key to the management of bowel obstruction. Plain abdominal radiographs combined with history, clinical exam, and laboratory findings are essential for further individualized strategies. If the cause of obstruction is obvious after plain films and there is a need for emergent surgery, no further imaging is required. In all other cases, multislice CT with at least intravenous and rectal contrast is the method of choice due to its broad diagnostic spectrum. If CT is not available, contrast enema is recommended in suspected large bowel obstruction. Oral administration of water-soluble contrast agents has no significant value in the workup of bowel obstruction.

Small-bowel obstruction: coronal reformations from isotropic voxels at 16-section multi-detector row CT

PURPOSE

To retrospectively assess the added value of coronal reformations of the abdomen and pelvis from isotropic voxels by using 16-section multi-detector row computed tomography (CT) for the diagnosis of small-bowel obstruction (SBO).

MATERIALS AND METHODS

This HIPAA-compliant study was approved by the institutional review board of this medical center with a waiver of informed consent. One hundred consecutive patients (40 men and 60 women; mean age, 55 years) suspected of having SBO and abdominal pain underwent 16-section multi-detector row CT with coronal reformations. Twenty-nine patients had a final diagnosis of SBO, and 71 patients did not. Three independent readers blinded to the diagnosis interpreted the CT scout scan, then transverse scans alone, and then transverse plus coronal scans for the presence of SBO and abnormal wall enhancement. Confidence was scored with a 1-5 scale (1 = absent, 5 = present).

RESULTS

Mean sensitivity and specificity of CT scout alone, transverse CT alone, and transverse plus coronal CT for the diagnosis of SBO were 88% and 86%, 87% and 87%, and 87% and 90%, respectively (not significant). In patients without SBO, transverse plus coronal CT enhanced confidence in the exclusion of SBO (P = .01). In patients with SBO, transverse plus coronal CT enhanced confidence in the diagnosis of SBO and identification of abnormal wall enhancement (P = .01).

CONCLUSION

Transverse 16-section multi-detector row CT data sets are an excellent test for the diagnosis of SBO, while the addition of coronal reformations obtained from these isotropic data sets adds confidence to the diagnosis and exclusion of SBO.