Multidetector computed tomography of mesenteric ischaemia

Could CT finding of gas in the sole mesenteric artery be a sign of a severe acute ischemia? Presentation of a rare fatal case and a literature review

Contrast-enhanced abdominal CT is the gold standard for the diagnosis of acute mesenteric ischemia (AMI). CT findings include several anomalies like bowel wall thickening, thinning, attenuation, decreased enhancement, dilated fluid-filled loops, pneumatosis, and portal venous gas. A rare case of gas found only in the superior mesenteric artery (SMA) is presented. A contrast-enhanced CT scan was performed in emergency on an 80-year-old man with vague and diffuse abdominal pain, which showed findings of occlusive AMI. Gas was found in the context of the SMA and its branches, but not in the mesenteric and portal veins. The patient underwent emergency surgery but he died the next day in the intensive care unit for complications. The rare CT finding of gas in SMA during an AMI should be considered a radiological sign of irreversible intestinal damage: surgical prompt intervention is needed, even if the mortality rate is high.

Imaging of Bowel Ischemia: An Update, From the AJR Special Series on Emergency Radiology

Acute mesenteric ischemia is a life-threatening condition that results from abrupt reduction in or cessation of blood flow to the bowel. Characterized by nonspecific abdominal symptoms, mesenteric ischemia is infrequently encountered and commonly misdiagnosed, with potentially catastrophic consequences. Prompt clinical diagnosis and early implementation of therapeutic interventions are critical to improving patient outcomes. Because cross-sectional imaging plays a key role in the diagnosis of mesenteric ischemia, radiologists must be familiar with the varied imaging manifestations of intestinal ischemia. Thus, the objectives of this article are to review the various types and common causes of mesenteric ischemia and to describe its spectrum of multimodality imaging findings, with special attention to novel imaging techniques and emerging diagnoses.

Mesenteric ischemia: a radiologic perspective

Mesenteric ischemia is a broad term encompassing several clinical conditions leading to impaired vascularity of bowel loops. Absence of specific clinical presentation and a definitive laboratory marker often lead to delayed diagnosis with high morbidity and mortality in the acute setting. Imaging plays a crucial role in the diagnosis and management. Multi-detector CT (MDCT) is the first line imaging modality for the evaluation of patients with suspected mesenteric ischemia and plays an important role for assessing its severity and complications. This review article highlights the causes, pathophysiology, imaging features and possible endovascular treatment options of mesenteric ischemia.

Comprehensive review of acute small bowel ischemia: CT imaging findings, pearls, and pitfalls

Acute small bowel ischemia is a life-threatening condition with a high mortality rate due to its lack of specific symptoms and laboratory profile, which render difficulty in establishing early diagnosis. The etiology of acute small bowel ischemia includes occlusive forms (arterial embolism, arterial thrombosis, and venous thrombosis) and nonocclusive mesenteric ischemia, of which arterial causes are far more common than venous causes. CT, the mainstay of accurate diagnoses, allows the identification of the features of vascular abnormalities and intestinal ischemic injuries, and helps clinicians to restore intestinal blood flow. Without treatment, the prognosis for acute small bowel ischemia is poor. A high index of suspicion and familiarity with the CT spectral findings of bowel ischemia are required to ensure rapid recognition of this condition.

Bowel ischemia in COVID-19: A systematic review

BACKGROUND

Gastrointestinal complications of COVID-19 have been reported over the last year. One such manifestation is bowel ischaemia. This study thus aims to provide a more holistic review of our current understanding of COVID-19-induced bowel ischaemia.

METHOD AND RESULTS

A meticulous search was performed using different keywords in PubMed and Google Scholar. Fifty-two articles were included in our study after applying inclusion and exclusion criteria and performing the qualitative assessment of the studies. A total of 25 702 patients were included in our study after the completion of the qualitative assessment.

DISCUSSION

The common symptoms of GIT in COVID-19 patients are as diarrhoea, vomiting, nausea and abdominal pain. The mechanism of bowel ischaemia is associated with the formation of emboli which is related to COVID-19's high affinity for angiotensin-converting enzyme-2 on enterocytes, affecting the superior mesenteric vessels. Clinically, patients present with abdominal pain and vomiting. CT angiography of the abdomen and pelvis showed acute intestinal ischaemia (mesenteric). Management is usually initiated with gastric decompression, fluid resuscitation, and haemodynamic support. Surgical intervention is also sought.

CONCLUSION

Intestinal ischaemia presenting in patients with COVID-19 has to be considered when symptoms of severe abdominal pain are present. More research and guidelines are required to triage patients with COVID-19 to suspect intestinal ischaemia and to help in diagnosis and management.

Chronic Mesenteric Ischemia: Differential Vascularsurgical Therapy and Its Outcome in a Single-Center Observational Study

Aim: The aim of this study was to investigate short-/long-term vascularsurgical patency and the outcome in chronic mesenteric ischemia (CMI) depending on the mesenteric revascularization technique and reflecting real-world data. Methods: This retrospective single-center observational study registered all patients who had undergone open vascularsurgical reconstruction because of CMI at a tertiary German university hospital comparing 1-versus (vs.) 2-vessel as well as antegrade versus retrograde reconstructions. Results: In total, 35 patients were enrolled (mean [± SD] age, 64 ± 13 [range, 45–83] years; sex ratio [m:f], 16:19 [46:54]) over 12 years. Three patients with symptoms of mesenteric ischemia because of rare causes (radiation-induced and median arcuate ligament syndrome) have been excluded. While 51% of patients underwent 1-vessel reconstruction, 49% underwent 2-vessel reconstruction. There was a trend of (i) more perioperative complications in the 2-vessel group (88.2% vs. 55.6%, p = 0.06) and (ii) higher morbidity at 1 year in the 2-vessel versus 1-vessel group (57.1% and 42.9%, respectively; p = 0.466), while the morbidity of the 2-vessel versus 1-vessel group at 5 years (100% vs. 33.3%) was significantly different (p = 0.009). The mortality was greater in the 2-vessel versus 1-vessel group as it was significantly different in the early postoperative period (31.3% vs. 0, p = 0.016) and at 1 year (50% vs. 0, p = 0.005) and 5 years (100% vs. 11%, p = 0.003). Regarding overall survival, the 1-vessel group showed a significant superiority above the 2-vessel group (p = 0.004). Actually, there was no significant difference of early postoperative morbidity comparing the retrograde and antegrade group (p = 0.285) as well as at 1 year and 5 years (p = 0.715 and p = 0.620, respectively). In addition, there was no significantly different postoperative mortality in antegrade versus retrograde group at each time. Specific and general complication rates were 62.9% and 57.1%, respectively, resulting in an overall morbidity of 77.1% (mortality, 20%). Conclusion: The vascular surgeon should be prepared to perform various procedures of mesenteric reconstruction to tailor the operative strategy to the specific needs of the individual patient.

Acute Mesenteric Ischemia: A Challenge for the Acute Care Surgeon

Acute mesenteric ischemia is considered uncommon, but it appears to be more frequent cause of acute abdomen than appendicitis or ruptured abdominal aortic aneurysm in elderly patients. Surgical treatment without revascularization is associated with high overall mortality, up to 80%. The modern treatment of acute mesenteric ischemia requires collaboration of gastrointestinal surgeons, vascular surgeons, and interventional radiologists. Early revascularization may reduce the overall mortality associated with acute mesenteric ischemia by up to 50%. Clinical suspicion and contrast-enhanced computed tomography performed at early stage are keys to improve outcomes of acute mesenteric ischemia treatment. This review summarizes what the acute care surgeon needs to know about acute mesenteric ischemia with special emphasis on slowly progressing "acute on chronic" mesenteric ischemia.

Many faces of acute bowel ischemia: overview of radiologic staging

Acute bowel ischemia (ABI) can be life threatening with high mortality rate. In spite of the advances made in diagnosis and treatment of ABI, no significant change has occurred in the mortality over the past decade. ABI is potentially reversible with prompt diagnosis. The radiologist plays a central role in the initial diagnosis and preventing progression to irreversible intestinal ischemic injury or bowel necrosis. The most single imaging findings described in the literature are either non-specific or only present in the late stages of ABI, urging the use of a constellation of features to reach a more confident diagnosis. While ABI has been traditionally categorized based on the etiology with a wide spectrum of imaging findings overlapped with each other, the final decision for patient’s management is usually made on the stage of the ABI with respect to the underlying pathophysiology. In this review, we first discuss the pathologic stages of ischemia and then summarize the various imaging signs and causes of ABI. We also emphasize on the correlation of imaging findings and pathological staging of the disease. Finally, a management approach is proposed using combined clinical and radiological findings to determine whether the patient may benefit from surgery or not.

Pearls, Pitfalls, and Conditions that Mimic Mesenteric Ischemia at CT

Acute mesenteric ischemia (AMI) is a life-threatening condition with a high mortality rate. The diagnosis of AMI is challenging because patient symptoms and laboratory test results are often nonspecific. A high degree of clinical and radiologic suspicion is required for accurate and timely diagnosis. CT angiography of the abdomen and pelvis is the first-line imaging test for suspected AMI and should be expedited. A systematic "inside-out" approach to interpreting CT angiographic images, beginning with the bowel lumen and proceeding outward to the bowel wall, mesentery, vasculature, and extraintestinal viscera, provides radiologists with a practical framework to improve detection and synthesis of imaging findings. The subtypes of AMI are arterial and venoocclusive disease, nonocclusive ischemia, and strangulating bowel obstruction; each may demonstrate specific imaging findings. Chronic mesenteric ischemia is more insidious at onset and almost always secondary to atherosclerosis. Potential pitfalls in the diagnosis of AMI include mistaking pneumatosis as a sign that is specific for AMI and not an imaging finding, misinterpretation of adynamic ileus as a benign finding, and pseudopneumatosis. Several enterocolitides can mimic AMI at CT angiography, such as inflammatory bowel disease, infections, angioedema, and radiation-induced enterocolitis. Awareness of pitfalls, conditions that mimic AMI, and potential distinguishing clinical and imaging features can assist radiologists in making an early and accurate diagnosis of AMI. ^©RSNA, 2020.

Mesenteric ischemia: what the radiologist needs to know

Acute mesenteric ischemia (AMI) is a life-threatening condition that often presents with abdominal pain. Early diagnosis with contrast-enhanced computed tomography and revascularization can reduce the overall mortality in AMI. This article reviews practical etiological classification, pathophysiology of imaging manifestations and common pitfalls in intestinal ischemia.

Effect of Clinical Suspicion by Referral Physician and Early Outcomes in Patients with Acute Superior Mesenteric Artery Embolism

PURPOSE

To investigate the pattern of referral of patients with superior mesenteric artery embolism (SMAE) and its effect on outcomes, and to evaluate the risk factors for bowel infarction.

MATERIALS AND METHODS

This retrospective study included 66 consecutive patients diagnosed with acute SMAE between January 2001 and June 2016. Appropriate diagnosis by the referring physician was defined if the referral letter indicated that acute mesenteric ischemia was suspected or had been diagnosed at the referral center. Surgical delay was defined as the interval between symptom onset and surgery for definitive treatment.

RESULTS

Among 54 patients transferred from other centers, 26 patients (48.1%) were diagnosed appropriately by the referring physician. The rate of appropriate diagnosis was differed significantly by the use of computed tomography (CT) scan at referral center (25/35 with CT and 1/19 without CT, P=0.00). The surgical delay was significantly longer in patients without appropriate diagnosis compared with the patients with appropriate diagnosis (53.5±52.3 hours vs. 28.8±23.6 hours, P=0.04). Initially, 56 patients received surgical treatment with 31 underwent bowel resection due to infarction, 6 received conservative treatment, and the remaining 4 patients refused any treatment. The surgical delay, abdominal distension, tenderness, rebound tenderness, and level of C-reactive protein were associated with bowel infarction at initial operation. Overall in-hospital mortality was 32%.

CONCLUSION

A high index of suspicion with appropriate diagnostic modality, such as CT scan is crucial in patients with SMAE for reducing surgical delay as a risk factor of bowel infarction.

Acute mesenteric ischemia (part I) - Incidence, etiologies, and how to improve early diagnosis

Acute mesenteric ischemia (AMI) is generally thought to be a rare disease, but in fact, it is more common cause of acute abdomen than appendicitis or ruptured abdominal aortic aneurysm in patients over 75 years of age. In occlusive AMI, surgical treatment without revascularization is associated with as high as 80% overall mortality. It has been shown that early diagnosis with contrast-enhanced computed tomography and revascularization can reduce the overall mortality in AMI by up to 50%. However, only a minority of patients with AMI are being treated actively with revascularization in the United States, and the situation is very likely similar in Europe as well. What can we do to improve diagnostic performance, so that more patients get proper treatment? The diagnosis is a collaborative effort of emergency department surgeons, gastrointestinal and vascular surgeons, and radiologists. The etiological categorization of AMI should be practical and guide the therapy. Furthermore, the limitations of the diagnostic examinations need to be understood with special emphasis on computed tomography findings on patients with slowly progressing "acute-on-chronic" mesenteric ischemia.