Contrast-enhanced ultrasonography with Sonazoid™ for the evaluation of bowel ischemia

Contrast-enhanced ultrasonographic findings of non-occlusive mesenteric ischemia: a case series

PURPOSE

Diagnosis of non-occlusive mesenteric ischemia (NOMI) is difficult, with diagnostic imaging being mainly performed using angiography or contrast-enhanced computed tomography. Contrast-enhanced ultrasonography (CEUS) offers an alternative diagnostic method, although diagnosis of NOMI using CEUS is not common. In this report, we review CEUS findings in a series of patients with NOMI.

METHODS

The records of patients diagnosed with NOMI who underwent a surgical procedure in our institution between January 2015 and February 2020 were retrospectively assessed. Grayscale ultrasonography and CEUS findings were evaluated.

RESULTS

Ten patients (mean age 65 ± 25 years, 7 men) were studied. Grayscale ultrasonography revealed bowel dilatation, the presence of intestinal pneumatosis, portal venous gas, bowel wall thickening, and no or decreased peristalsis. A CEUS finding of note was a partial lack of enhancement of the bowel wall.

CONCLUSION

In a small case series of 10 patients with surgically/histopathology confirmed NOMI, partial lack of ultrasound contrast-enhancement of the bowel wall was observed.

Ultrasound of Small Bowel Obstruction: A Pictorial Review

Small bowel obstruction (SBO) is a common condition requiring urgent attention that may involve surgical treatment. Imaging is essential for the diagnosis and characterization of SBO because the clinical presentation and results of laboratory tests may be nonspecific. Ultrasound is an excellent initial imaging modality for assisting physicians in the rapid and accurate diagnosis of a variety of pathologies to expedite management. In the case of SBO diagnosis, ultrasound has an overall sensitivity of 92% (95% CI: 89–95%) and specificity of 93% (95% CI: 85–97%); the aim of this review is to examine the criteria for the diagnosis of SBO by ultrasound, which can be divided into diagnostic and staging criteria. The diagnostic criteria include the presence of dilated loops and abnormal peristalsis, while the staging criteria are represented by parietal and valvulae conniventes alterations and by the presence of free extraluminal fluid. Ultrasound has reasonably high accuracy compared to computed tomography (CT) scanning and may substantially decrease the time to diagnosis; moreover, ultrasound is also widely used in the monitoring and follow-up of patients undergoing conservative treatment, allowing the assessment of loop distension and the resumption of peristalsis.

Contrast-Enhanced Ultrasound (CEUS) in Non-Traumatic Abdominal Emergencies

Conventional ultrasound imaging (US) is the first-line investigation in acute non-traumatic abdominal emergencies, but sometimes it needs further examinations, such as computed tomography (CT), to reach a certain diagnosis. Contrast-enhanced ultrasound (CEUS), through injection of contrast medium, may provide the radiologist with additional information that could not be investigated with baseline US. It could help reach a diagnosis and rapidly determine the proper therapy in an emergency setting. The purpose of this review is to explain and illustrate the various possibilities and limitations of CEUS in acute non-traumatic abdominal diseases, in particular acute inflammation, parenchymal infarcts, and hemorrhages.

Gastrointestinal Ultrasound (GIUS) in Intestinal Emergencies - An EFSUMB Position Paper

An interdisciplinary group of European experts summarizes the value of gastrointestinal ultrasound (GIUS) in the management of three time-critical causes of acute abdomen: bowel obstruction, gastrointestinal perforation and acute ischemic bowel disease. Based on an extensive literature review, statements for a targeted diagnostic strategy in these intestinal emergencies are presented. GIUS is best established in case of small bowel obstruction. Metanalyses and prospective studies showed a sensitivity and specificity comparable to that of computed tomography (CT) and superior to plain X-ray. GIUS may save time and radiation exposure and has the advantage of displaying bowel function directly. Gastrointestinal perforation is more challenging for less experienced investigators. Although GIUS in experienced hands has a relatively high sensitivity to establish a correct diagnosis, CT is the most sensitive method in this situation. The spectrum of intestinal ischemia ranges from self-limited ischemic colitis to fatal intestinal infarction. In acute arterial mesenteric ischemia, GIUS may provide information, but prompt CT angiography is the gold standard. On the other end of the spectrum, ischemic colitis shows typical ultrasound features that allow correct diagnosis. GIUS here has a diagnostic performance similar to CT and helps to differentiate mild from severe ischemic colitis.

Regional perfusion monitoring in shock

PURPOSE OF REVIEW

Despite restoration of adequate systemic blood flow in patients with shock, single organs may remain hypoperfused. In this review, we summarize the results of a literature research on methods to monitor single organ perfusion in shock. We focused on methods to measure heart, brain, kidney, and/or visceral organ perfusion. Furthermore, only methods that can be used in real-time and at the bedside were included.

RECENT FINDINGS

We identified studies on physical examination techniques, electrocardiography, echocardiography, contrast-enhanced ultrasound, near-infrared spectroscopy, and Doppler sonography to assess single organ perfusion.

SUMMARY

Physical examination techniques have a reasonable negative predictive value to exclude single organ hypoperfusion but are nonspecific to detect it. Technical methods to indirectly measure myocardial perfusion include ECG and echocardiography. Contrast-enhanced ultrasound can quantify myocardial perfusion but has so far only been used to detect regional myocardial hypoperfusion. Near-infrared spectroscopy and transcranial Doppler sonography can be used to assess cerebral perfusion and determine autoregulation thresholds of the brain. Both Doppler and contrast-enhanced ultrasound techniques are novel methods to evaluate renal and visceral organ perfusion. A key limitation of most techniques is the inability to determine adequacy of organ blood flow to meet the organs' metabolic demands.

Two-dimensional and contrast-enhanced ultrasound of intestinal ischaemia in cats: four cases

OBJECTIVES

The aim of this study was to describe the results of two-dimensional (2D) and contrast-enhancement ultrasound (CEUS) in four cats with intestinal ischaemia.

METHODS

Data were collected from hospital records of all cats that had intestinal ischaemia between January 2012 and August 2018. The inclusion criteria were complete abdominal ultrasound examination, colour flow Doppler and CEUS of lesions, confirmation of intestinal ischaemia detected by visual assessment of avascular intestinal segment at surgery, and/or necropsy and histopathology. All images and video clips were reviewed by the same experienced operator.

RESULTS

Four cats with different intestinal ischaemic lesions were included in the study: duodenal perforating ulcer, jejunal necrotising enteritis, necrosis secondary to jejunojejunal intussusception and iatrogenic damage of jejunal arteries. On the 2D ultrasound, all intestinal lesions were characterised by non-specific findings: focal hypoechoic wall thickening with loss of normal layering associated with hyperechoic mesentery surrounding the intestinal tract. CEUS showed a reduced or absent enhancement of the intestinal lesions in comparison to the surrounding perfused wall.

CONCLUSIONS AND RELEVANCE

Intestinal ischaemia is a potentially fatal disorder. Grey-scale, colour and power Doppler ultrasonography are not sensitive for evaluating this condition. Our preliminary findings illustrate the usefulness of CEUS for the detection of intestinal wall impaired perfusion in cats.

Emergency radiology

US has a relevant role in the initial assessment of non-traumatic emergencies of the abdomen, sometimes being conclusive and some other times for selecting the patients for further imaging with CT. Injection of a contrast medium may give to the radiologist additional information to that obtained at baseline US and Doppler examination, since real-time, contrast-enhanced US (CEUS) may allow observing findings in the abdomen not recognizable at baseline US or even at color Doppler imaging. Extravascular use of microbubbles may also be useful in clinical practice to rapidly solve a number of unclear aspects. CEUS has a number of distinct advantages in acute patients, including its quickness, low invasiveness, and its possible bedside use. The information based on contrast enhancement is useful for initial diagnosis, therapeutic decision making, and follow-up of the critically ill patients. The purpose of this review is to illustrate the possibilities and limitations of abdominal CEUS in the acute setting, with special emphasis on the detection and characterization of acute inflammatory processes, infarcts, and hemorrhages.