Multidetector row computed tomography in bowel obstruction. Part 2. Large bowel obstruction

Diagnostic significance of multidetector computed tomography (MDCT) in patients with small bowel obstruction: a meta-analysis

PURPOSE

To assess the diagnostic value of multidetector computed tomography (MDCT) in small bowel obstruction (SBO) patients.

METHODS

Relevant literature was searched from the Cochrane Library, Pubmed and Embase. The extracted effective data was calculated using the Meta-Disc 1.4 software; statistical heterogeneity was evaluated using Cochran's Q test and I².

RESULTS

A total of five articles were selected for the meta-analysis. In addition, the pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), as well as the diagnostic odds ratio (DOR) were 0.878 (95% CI 0.822-0.921), 0.807 (95% CI 0.753-0.854), 8.137 (95% CI 2.268-29.192), 0.127 (95% CI 0.040-0.4078) and 72.384 (95% CI 10.841-483.31), respectively. Furthermore, the AUC was 0.9648 with the Q of 0.9116.

CONCLUSIONS

The data suggest that MDCT is an effective method for diagnosis of SBO.

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.

Differential Diagnosis of Colonic Strictures: Pictorial Review with Illustrations from Computed Tomography Colonography

Strictures of the colon can lead to significant morbidity requiring surgical management. The etiology of strictures is broad and generally categorized as benign, malignant, or pseudostrictures. Computed tomography (CT) is a crucial imaging modality in the assessment and characterization of colonic pathologies but colonoscopy remains the diagnostic gold standard. However, in the setting of incomplete colonoscopy due to strictures, the imaging features of CT will be relied on. This review will focus on the CT features of different colon pathologies leading to strictures and will be illustrated with images from 10 years of experience with CT colonography at our institutions from 2002-2012 (Hotel Dieu Hospital, Queen's University and Mount Sinai Hospital, University of Toronto).

Colorectal cancer emergencies

INTRODUCTION

Colorectal cancer (CRC) is a common type of malignancy encountered in the United States. A significant proportion of patients with CRC will seek emergency medical care during the course of their illness and treatment.

BACKGROUND

Emergent presentations can be the result of either local tumor invasion, regional progression, or therapeutic techniques. Specific complications of CRC which present emergently include rectal bleeding, abdominal pain, and bowel obstruction. Less common issues encountered include malignant ascites, neutropenic enterocolitis, and radiation enteropathy.

CONCLUSION

The care of CRC patients in the setting of an acute severe illness typically requires the joint efforts of the emergency medical team in consultation with surgical, medical, and radiation oncology. A high degree of suspicion for the typical and atypical complications of CRC is important for all clinicians who are responsible for the care of these patients.

Radiological diagnosis of large-bowel obstruction: neoplastic etiology

Large-bowel obstruction (LBO) is a relatively common abdominal emergency. The CT exam has become the most important imaging modality for the diagnosis of LBO, following abdominal ultrasound and plain radiography. The recent multi-detector CT (MD-CT) is able to clarify the etiology of LBO and to help in deciding how to treat LBO. Therefore, it is important for the radiologists to become familiar with the imaging findings of LBO, including plain radiograph and CT, due to various causes. In this article, we have shown the characteristics of the radiological findings including plain radiograph, barium study, and CT as well as their correlations with pathologic findings of LBO. The etiology of LBO is usually divided into neoplastic diseases and nonneoplastic diseases. However, the most common cause is the neoplastic etiology. Now, we can afford the critical information concerning the level of obstruction, its cause, the viability of the involved bowel loops, and a decision-making regarding the therapy for patients with LBO, using MD-CT high technology.

Volvulus of the ascending colon in a non-rotated midgut: Plain film and MDCT findings

Colonic volvulus is a relatively uncommon cause of large bowel obstruction usually involving mobile, intra-peritoneal, colonic segments. Congenital or acquired anatomic variation may be associated with an increased risk of colonic volvulus which can occasionally involve retro-peritoneal segments. We report a case of 54-year-old female who presented to our Institution to perform a plain abdominal film series for acute onset of cramping abdominal pain. Both the upright and supine films showed signs of acute colonic obstruction which was thought to be due to an internal hernia of the transverse colon into the lesser sac. The patient was therefore submitted to a multi-detector contrast-enhanced computed tomography (CT). CT findings were initially thought to be consistent with the presumed diagnosis of internal hernia but further evaluation and coronal reformatting clearly depicted the presence of a colonic volvulus possibly resulting from a retro-gastric colon. At surgery, a volvulus of the ascending colon was found and a right hemi-colectomy had to be performed. However, a non rotated midgut with a right-sided duodeno-jejunal flexure and a left sided colon was also found at laparotomy and overlooked in the pre-operative CT. Retrospective evaluation of CT images was therefore performed and a number of CT signs of intestinal malrotation could be identified.

Radiological diagnosis of large-bowel obstruction: nonneoplastic etiology

Large-bowel obstruction (LBO) is a relatively common abdominal emergency. Computed tomography (CT) diagnosis of LBO is often easy, but it is essential to clarify LBO etiology and to decide how to treat it. Therefore, it is important for the radiologist to become familiar with the imaging findings of LBO, including plain radiography and CT, to determine its various causes, as well as the many diseases mimicking LBO. In this article, we show the characteristics of radiological findings of plain radiograph, barium study, and CT and their correlations with pathologic findings. LBO etiology comprises two main categories: neoplastic and nonneoplastic disease. However, the primary causes of LBO are neoplastic etiologies, and nonneoplastic causes are relatively uncommon and unfamiliar to many radiologists in clinical practice. Therefore, in this review, we present nonneoplastic etiology of LBO and diseases simulating LBO and provide critical information concerning the causes of LBO and viability of the involved bowel loops.

Techniques and Outcomes of Endoscopic Decompression Using Transanal Drainage Tube Placement for Acute Left-sided Colorectal Obstruction

BACKGROUND

If it is possible, endoscopic decompression for acute left-sided colorectal obstruction will be effective in critically ill patients. This study was to evaluate the techniques and outcomes of transanal drainage tube placement following urgent colonoscopy in management of acute left-sided colorectal obstruction.

METHODS

From January 2000 to December 2009, 69 consecutive patients (36 males, age 38 to 94, mean = 71) were hospitalized because of acute left-sided colorectal obstruction. Urgent colonoscopy was performed within 12 hours of entry for diagnosis and treatment (mean time, 6.5 hours). Endoscopic decompression using a transanal drainage tube was attempted. Clinical success, methods used, and complications were retrospectively evaluated.

RESULTS

The cause of obstruction was colorectal carcinoma in 66 patients (96%). The site of obstruction was sigmoid colon in 37 (54%), rectum in 20 (29%), and descending colon in 12 (17%). Out of 69 patients, endoscopic decompression using the transanal drainage tube was successful in 66 (96%). The use of combination of transanal drainage tube and the equipped guidewire enabled endoscopic decompression was successful in 45 patients (65%), though a small-diameter upper endoscope was used in 2 patients to introduce the guidewire beyond the obstruction. Perforation during the placement developed in 2 patients and one patient was unsuccessful.

CONCLUSIONS

Transanal drainage tube placement following urgent colonoscopy was effective in the management of acute left-sided colorectal obstruction. In the majority of patients, the materials and methods used for the transanal drainage tube placement were simple and easy.

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.

Emergency and urgent surgery

Patients presenting with general surgical emergencies are hypovolemic, and require early aggressive resuscitative efforts. Although these efforts may safely be accomplished preoperatively in a select subset of patients, it is often the combined task of surgeons, anesthesiologists, and internists to optimize these critically ill patients in the intraoperative and postoperative period. Early surgical consultation and intervention can be lifesaving. This article presents the current state of emergency surgical care in the United States and the approach to the patient with an emergency surgical illness. The aggressiveness of the surgical intervention is patient- and disease-specific and requires frequent and open communication between all health care providers, the patient, and his or her family. In addition to aggressive resuscitation, life-threatening general surgical conditions often require specific diagnostic and therapeutic interventions.

Emergency and urgent surgery

Patients presenting with general surgical emergencies are hypovolemic, and require early aggressive resuscitative efforts. Although these efforts may safely be accomplished preoperatively in a select subset of patients, it is often the combined task of surgeons, anesthesiologists, and internists to optimize these critically ill patients in the intraoperative and postoperative period. Early surgical consultation and intervention can be lifesaving. This article presents the current state of emergency surgical care in the United States and the approach to the patient with an emergency surgical illness. The aggressiveness of the surgical intervention is patient- and disease-specific and requires frequent and open communication between all health care providers, the patient, and his or her family. In addition to aggressive resuscitation, life-threatening general surgical conditions often require specific diagnostic and therapeutic interventions.

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.

The demise of the instant/unprepared contrast enema in large bowel obstruction

OBJECTIVE

Imaging the colon in suspected acute large bowel obstruction (LBO) is traditionally carried out with a supine abdominal X-ray (AXR) and erect chest X-ray. If there is no clinical or radiological evidence to suggest a perforation, then an unprepared barium or water-soluble contrast enema (CE) can be performed to confirm the presence of and demonstrate the site of obstruction. The advent of modern, fast multidetector CT (MDCT) scanners has changed management strategies for acute abdominal conditions including suspected LBO in all groups of patients especially the elderly, infirm and those on ITU/HDU.

METHOD

A retrospective case note analysis was carried over a 7-year period in a single centre. The study criteria involved investigation of suspected LBO with CE, CT and MDCT.

RESULTS

It showed a reduction in the number of contrast enemas performed.

CONCLUSION

MDCT was shown to be more accurate in the diagnosis of LBO, is usually available on a 24-h basis, and in many institutions has replaced the urgent CE in this group of patients. This also has the advantage of excluding incidental findings and in staging malignant disease.

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.

Four-section multidetector computed tomographic imaging of bowel obstruction: usefulness of axial and coronal plane combined reading

OBJECTIVE

To compare the diagnostic performance of axial and coronal views in multidetector-row computed tomography (MDCT) of patients with small-bowel obstruction (SBO) or large-bowel obstruction (LBO).

MATERIALS AND METHODS

Among 157 patients with clinical and radiographic findings of BO, 73 patients, who underwent MDCT and were found to have surgically proven SBO (49/73) or LBO (24/73), were retrospectively evaluated. Portal-enhanced MDCT was performed using 4 x 2.5-mm collimation; 3-mm-thick axial images were reconstructed with 2 mm of increment. Coronal views were reformatted using 3-mm-thick sections with 1 mm of increment. Three radiologists analyzed axial (session A), coronal (session B), and axial plus coronal images (session C) to identify the site, cause, and type of BO. To correlate surgical findings and MDCT results, the bowel was divided into duodenum, oral jejunum, aboral jejunum, oral ileum, aboral ileum, cecum/ascending colon, transverse colon, descending colon, and sigmoid colon/rectum. The mean diagnostic accuracy and the mean confidence score of each reader and each reading session were calculated.

RESULTS

The diagnostic accuracy of axial images was higher than that of coronal views (P = 0.014) in SBO, whereas no significant differences were found in LBO. The definition of the SBO cause was correctly assessed in 45 of 49 patients during session A, in 40 of 49 during session B, and in 45 of 49 during session C. In patients with LBO, the cause was correctly assessed in 21 of 24 patients during session A and in 22 of 24 patients during sessions B and C. All readers interpreted axial plus coronal images with a significantly higher confidence level than axial or coronal views alone, either for the detection of the site (P = 0.002) or for the identification of the cause (P < 0.001) of SBO and LBO.

CONCLUSION

The MDCT allowed accurate detection of the site and the cause of obstruction. In SBO, axial images yielded a higher diagnostic accuracy than coronal views, whereas in LBO, no differences were found between axial and coronal planes. The reading of axial plus coronal views significantly improved diagnostic confidence.

[Intestinal endometriosis. Current status]

Endometriosis affects a wide spectrum of premenopausal women. Intestinal involvement, affecting mainly the large bowel and sometimes the small bowel, is much less frequent. Diagnosis is relatively straightforward in women with long standing pelvic endometriosis but is difficult in acute intestinal obstruction, since a diagnosis of endometriosis is not often considered in this entity. We performed an exhaustive review of the medical literature, including the option of medical treatment, which is rarely effective in intestinal endometriosis. In most patients with intestinal symptoms, the disease is so severe that surgical treatment is required. Recent studies indicate that the most effective approach is laparoscopic. We analyze the most important classical and recent series of patients and discuss treatment results.

Bowel obstruction: comparison between multidetector-row CT axial and coronal planes

Acute obstruction of bowel is a common reason for presentation to the emergency department. Causes of obstruction are multiple (tumorous, inflammatory, postoperative, or congenital), but the clinical presentation is usually not specific. The abdominal radiographs are sometimes inconclusive, and cause of obstruction is rarely detected. Computed tomography (CT) has been shown to be useful in revealing the site and the cause of obstruction. Although radiologists are skilled in the interpretation of CT scans in the axial plane, the development of multidetector-row CT coupled with fast reconstruction hardware and software has stimulated interest in viewing abdomen in coronal plane. In the evaluation of small bowel obstruction, coronal plane serves as a useful adjunct for the identification of the point of transition from dilated to decompressed bowel. On the other hand, in the evaluation of large bowel obstruction, coronal planes could replace axial images in the evaluation of the site and cause of obstruction, although the best values of confidence level in the diagnosis are reached when interpreting axial combined with coronal images.