Preoperative evaluation by magnetic resonance imaging in patients with bowel obstruction

Midgut Volvulus in a Pregnant Patient Presenting With Abdominal Pain

Abdominal pain is a common symptom during pregnancy, but bowel obstruction as the cause is a rare phenomenon. Moreover, intestinal volvulus is an even more unusual cause of obstruction during pregnancy and normally involves the sigmoid colon. We report a unique case of midgut volvulus in a pregnant patient entering her third trimester who presented to the hospital with abdominal pain. Our case demonstrates the safety of computed topography in pregnancy while restricting radiation dose and highlights the need to have a high index of suspicion for bowel obstruction when approaching a pregnant patient with abdominal pain.

Diagnostic performance of multi-slice CT angiography combined with enterography for small bowel obstruction and intestinal ischaemia

INTRODUCTION

This study was performed to evaluate the diagnostic performance of multi-slice CT angiography combined with enterography in determining the cause and location of obstruction as well as intestinal ischaemia in patients with small bowel obstruction (SBO).

METHODS

This study retrospectively summarized the image data of 57 SBO patients who received both multi-slice CT angiography and enterography examination between December 2012 and May 2013. The CT diagnoses of SBO and intestinal ischaemia were correlated with the findings at surgery or digital subtraction angiography, which were set as standard references.

RESULTS

Multi-slice CT angiography and enterography indicated that the cause of SBO in three patients was misjudged, suggesting a diagnostic accuracy of 94.7%. In one patient the level of obstruction was incorrect, demonstrating a diagnostic accuracy of 98.2%. Based on the results of the receiver operating characteristic (ROC) curve analysis, the diagnostic criterion for ischaemic SBO was at least two of the four CT signs (circumferential bowel wall thickening, reduced enhancement of the intestinal wall, mesenteric oedema and mesenteric vascular engorgement). The criterion yielded a sensitivity of 94.4%, a specificity of 92.3%, a positive predicted value of 85.0% and a negative predicted value of 97.3%, and the area under curve (AUC) was 0.92 (95% CI, 0.85-0.99).

CONCLUSION

Multi-slice CT angiography and enterography have high diagnostic value in identifying the cause and site of SBO. In addition, the suggested diagnostic criterion using CT signs is helpful for diagnosing intestinal ischaemia in SBO patients.

Gadolinium-chitosan nanoparticles as a novel contrast agent for potential use in clinical bowel-targeted MRI: a feasibility study in healthy rats

BACKGROUND

MRI is of increasing importance in the diagnostic evaluation of gastrointestinal diseases, with depiction of mucosal enhancement obtained with conventional intravenous contrast. Routine clinical use of contrast agents has been carried out using intravenous injection for mucosal imaging. Contrast agents that specifically target the intestinal mucosa are therefore needed to improve clinical imaging of the mucosal surface.

PURPOSE

To synthesize a novel contrast agent for gadopentetic acid (Gd-DTPA)-loaded chitosan nanoparticles and observe the absorption of the nanoparticles in the colon wall of healthy rats by MR imaging in vivo.

MATERIAL AND METHODS

A contrast agent was successfully synthesized by a modified emulsion coalescence method, and the resulting agents were characterized in detail by dynamic light-scattering spectroscopy and inductively coupled plasma emission spectroscopy. The cytotoxicity of Gd-chitosan nanoparticles was evaluated by an MTT assay. Gadolinium-chitosan (Gd@chitosan) nanoparticles were administered to the colon mucosa of healthy rats by rectal administration, and MRI scans in vivo were carried out with a 3.0 T imaging scanner at various time points.

RESULTS

The prepared Gd@chitosan nanoparticles were ~420 nm in diameter with a 74.4% Gd-DTPA content. The MTT assay indicated little cytotoxicity. MRI results showed that nanoparticles can be retained in both the stratum submucosum and epithelial cells of the colon for almost 80 min. Transmission electron microscopy images further revealed that Gd@chitosan nanoparticles were localized inside the mucosal cells or intercellular space, while tissue from Gd-DTPA aqueous solution administration showed nothing. Due to the infusion of Gd@chitosan nanoparticles, the MR signal intensity of colon mucosa increased from about 6% to 35%, and the contrast enhancement was highest at 20 min after administration.

CONCLUSION

Gd@chitosan nanoparticles with high Gd-DTPA content were successfully prepared for use as a novel MRI contrast agent. All results indicated that rectally administered Gd@chitosan nanoparticles have the potential for MRI diagnosis of colon mucosal disease.

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.

[Sigmoid volvulus, a rare complication of pregnancy]

Sigmoid volvulus complicating pregnancy is a rare complication with less than 80 cases reported in literature. We report the case of a young pregnant woman, admitted for sigmoid volvulus. The sigmoid volvulus was resected and Bouilly-Volkmann's colostomy was performed. According to this case and depending on the literature, the authors discuss the diagnostic and therapeutic modalities proposed for this rare entity.

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.

Magnetic resonance imaging of abdominal pain during pregnancy

The objective of this review is to demonstrate magnetic resonance imaging as an important adjunct to ultrasound and computed tomography in the evaluation of the pregnant patient with abdominal pain. With the advent of ultrafast T2-weighted pulse sequences, fetal and bowel motion cause minimal artifact on the images. An accurate diagnosis can often be made in a few minutes based on these high-contrast images performed in 2 or 3 planes. T1-weighted gradient echo images with and without fat saturation are useful for identifying blood and fat, especially in the case of adnexal masses. Gadolinium-diethylenetriamine pentaacetic acid is rarely used to diagnose inflammatory or obstructive disease and is reserved for those patients with suspected malignancies.

ACR Appropriateness Criteria® on Suspected Small-Bowel Obstruction

With no one generally accepted approach to evaluate patients with suspected small-bowel obstruction (SBO), standard CT has emerged as the preeminent imaging modality and should be considered in the initial evaluation of patients with suspected high-grade SBO. Playing less significant roles in the diagnosis of acute SBO are barium enemas and the small-bowel examination.

Progressive increase of bowel wall thickness is a reliable indicator for surgery in patients with adhesive small bowel obstruction

PURPOSE

The aim of this study was to determine whether progressive increase of bowel wall thickness during nonoperative treatment is a reliable indicator for surgery in patients with adhesive small bowel obstruction.

METHODS

The study consisted of a prospective case series of 121 patients with adhesive small bowel obstruction who underwent an abdominal ultrasonographic examination. The results of ultrasonographic examinations were classified into two groups according to the presence (Group I) or absence (Group II) of bowel wall thickening. Bowel wall thickening was recognized as a visible small bowel wall > or =3 mm in width as seen by ultrasonographic examination. The findings of subsequent ultrasonographic examinations taken 24 hours later were compared with those taken at admission. Surgery was determined based on the presence of any toxic signs or the failure of nonoperative treatment. The number of patients who had successful nonoperative treatment, the number of patients who underwent surgeries, and the number of complications in each group were calculated to correlate with the ultrasonographic findings.

RESULTS

There are 49 and 72 patients in Groups I and II, respectively. The number of patients who had successful nonoperative treatment and number of patients who underwent surgeries in Group I are 40 (81.6 percent) and 9 (18.4 percent) and in Group II the numbers are 68 (94.4 percent) and four (5.6 percent), respectively (P = 0.036). All 12 (100 percent) patients with progressive increase of bowel wall thickness underwent surgery. Progressive increase of bowel wall thickness as an indicator for surgery has a sensitivity of 92.3 percent (95 percent confidence interval, 62.1-99.6 percent) and a specificity of 100 percent (95 percent confidence interval, 95.7-100 percent).

CONCLUSIONS

Patients with initial bowel wall thickening have a higher incidence of surgery, and progressive increase of bowel wall thickness that appears 24 hours later is a reliable indicator for surgery in patients with adhesive small bowel obstruction.

Kinematics of the uterus: cine mode MR imaging

Cine mode magnetic resonance (MR) imaging has allowed evaluation of kinematics of the pelvis. Visualization of dynamic changes under strain facilitates evaluation of prolapses and adhesions between organs. The uterus, an organ of smooth muscle, has an inherent contractility that characterizes it as different from other visceral organs. This sustained contraction has occasionally been shown on static images as a finding masquerading as a leiomyoma or as adenomyosis. Cine mode MR imaging clearly shows the configuration of the myometrium during these dynamic changes, as well as its signal intensity during contractions. Uterine peristalsis, the subtle and rhythmic contractions of the inner myometrium, is also clearly identifiable on cine mode images as a wavy movement of the endometrium and/or inner myometrium. The direction and frequency of uterine peristalsis are different in each of the menstrual cycle phases and are thought to have important roles in uterine function, such as in fertility and menstrual blood discharge. Elucidation of these kinematics of the uterus will help in the evaluation of static MR images and study of the physiology of the uterus. Cine MR imaging is a novel technique for diagnosis and evaluation of the pelvic organs, especially the uterus.

CT diagnosis of small bowel obstruction: scanning technique, interpretation and role in the diagnosis

Intestinal obstruction is a relatively common condition with diagnosis based on the clinical signs, patient history, and radiographical findings. Once suspected, its presence should be determined and if present, the site and cause of obstruction, and presence of strangulation should be assessed for the appropriate patient management. With the recent technological developments, the role of computed tomography (CT) in the diagnosis of bowel obstruction has expanded. The examination should be performed with intravenous contrast administration and thinner sections and multi-planner image reformation are recommended to evaluate a site of particular interest. CT is reported to have a sensitivity refer to detection of a small bowel obstruction at over 90% for complete or high-grade obstruction and to disclose causes of obstruction in 70% to 95% of cases. CT also provides characteristic findings indicating the presence of closed-loop obstruction and intestinal ischemia, which leads to appropriate and timely management for these emergent cases.

Intestinal obstruction and perforation--the role of the gastroenterologist

Intestinal obstruction belongs to highly severe conditions in gastroenterology, namely from the viewpoint of quick and correct diagnosis as well as at determining rational and effective therapy. Etiological multifactorial characteristics leading to processes resulting in mechanical or dynamic obstruction of the intestine, often referred to as paralytic ileus, are undoubtedly serious factors influencing the accuracy of diagnosis and therapeutic approach. Digestive endoscopy is a mandatory method in the diagnosis of intestinal obstructions. Diagnostic endoscopy, colonoscopy in the involvement of the large intestine or enteroscopy in the case of incomplete obstruction of the small intestine are the methods indicated in the majority of obstructive intestinal lesions. Besides their diagnostic importance, they also enable an effective therapeutic approach which may immediately follow the diagnostic intervention. Besides endoscopy that--due to the nature of performance--belongs to invasive methods, the diagnosis of obstructive intestinal processes is unthinkable without the use of non-invasive imaging methods. Abdominal ultrasound examination, a widely applied method, provides--under optimal examination conditions--information, e.g., about the width of the intestinal lumen or about the intestinal wall thickness; however, the specificity of investigation is not always sufficient. Both specificity and sensitivity of exploration are increased by a plain X-ray of the abdomen supplementing the ultrasound examination. Better results are achieved when the abdominal cavity is inspected by means of spiral CT examination that is nowadays not fashionable but highly effectively applied in the modification of the so-called CT enteroclysis or CT colonography. The usage of magnetic resonance (e.g. virtual colonography) is similar, but its efficacy is lower than that of CT examination. From a gastroenterologist's perspective, endoscopic examination is the fundamental diagnostic and therapeutic method. However, endoscopic examination is initially limited by the cardiopulmonary state of the patient--in a number of cases, first the cardiopulmonary condition must be stabilized, dysbalance of water and mineral state must be restored, and only then can endoscopic investigation be carried out. The application of enteroscopy in small intestine disorders is only suitable in cases where air must be aspirated from the region of the stomach and mainly small intestine as it happens, for example, in acute intestinal pseudo-obstruction. The success of complex conservative therapy in these states is reached in 80% of the cases. In acute and complete intestinal obstruction, a surgical treatment performed in time is the only method. In these cases, the importance of identification of obstruction and timing of the intervention performance from the viewpoint of the patient's survival is explicitly the principal and life-saving concern. In acute intestinal obstructions developing in patients with malignant affection of the intestine, it is necessary to choose--according to the obstruction location and general state of the patient--either urgently performed surgery or palliative endoscopic intervention which is the reduction of the intestinal lumen of the growing tumor mass and following insertion of a drain. This method also concerns lesions localized in the left half of the abdominal cavity, i.e. in the region of the rectosigmoid and descending part of the colon. Most patients in whom acute intestinal obstruction developed on the basis of malignant disease are risk and polymorbid subjects, and acute surgical intervention may be either impracticable or highly stressing. In such cases it is therefore helpful to insert a drain and to bridge the obstructed area after restoring the cardiopulmonary state including adjustment of the aqueous and mineral environment. Later, the performance of an elective surgical intervention is safer. Another alternative before inserting a drain is the dilatation of the stenotic site by means of a balloon, followed by stenting. Up until today, various types of intestinal drains have been introduced--they have always been self-expanding metallic stents. Just the application of self-expanding stents in patients with malignant intestinal obstruction and the endoscopic possibility of dilatations of benign intestinal obstructions with dilatation balloons are the most significant therapeutic contributions of digestive endoscopy in these states.