Value of multislice computed tomography in the diagnosis of acute mesenteric ischemia

Comparison of Endovascular Therapy and Open Surgical Revascularization in Patients With Acute Superior Mesenteric Artery Occlusion: A Large-Scale Analysis Based on the JROAD-DPC Database

BACKGROUND

Acute mesenteric ischemia is rare, and few large-scale trials have evaluated endovascular therapy (EVT) and open surgical revascularization (OS). This study aimed to assess clinical outcomes after EVT or OS for acute superior mesenteric artery occlusion and identify predictors of mortality and bowel resection.

METHODS AND RESULTS

Data from the Japanese Registry of All Cardiac and Vascular Diseases-Diagnosis Procedure Combination (JROAD-DPC) database from April 2012 to March 2020 were retrospectively analyzed. Overall, 746 patients with acute superior mesenteric artery occlusion who underwent revascularization were classified into 2 groups: EVT (n=475) or OS (n=271). The primary clinical outcome was in-hospital mortality. The secondary outcomes were bowel resection, bleeding complications (transfusion or endoscopic hemostasis), major adverse cardiovascular events, hospitalization duration, and cost. The in-hospital death or bowel resection rate was ≈30%. In-hospital mortality (22.5% versus 21.4%, P=0.72), bowel resection (8.2% versus 8.5%, P=0.90), and major adverse cardiovascular events (11.6% versus 9.2%, P=0.32) were comparable between the EVT and OS groups. Hospitalization duration in the EVT group was 6 days shorter than that in the OS group, and total hospitalization cost was 0.88 million yen lower. Interaction analyses revealed that EVT and OS had no significant difference in terms of in-hospital death in patients with thromboembolic and atherothrombotic characteristics. Advanced age, decreased activities of daily living, chronic kidney disease, and old myocardial infarction were significant predictive factors for in-hospital mortality. Diabetes was a predictor of bowel resection after revascularization.

CONCLUSIONS

EVT was comparable to OS in terms of clinical outcomes in patients with acute superior mesenteric artery occlusion. Some predictive factors for mortality or bowel resection were obtained.

REGISTRATION

URL: www.umin.ac.jp/ctr/; Unique Identifier: UMIN000045240.

Diagnostic Role of Multi-Detector Computed Tomography in Acute Mesenteric Ischemia

Mesenteric ischemia diagnosis is challenging, with an overall mortality of up to 50% of cases despite advances in treatment. The main problem that affects the outcome is delayed diagnosis because of non-specific clinical presentation. Multi-Detector CT Angiography (MDCTA) is the first-line investigation for the suspected diagnosis of vascular abdominal pathologies and the diagnostic test of choice in suspected mesenteric bowel ischemia. MDCTA can accurately detect the presence of arterial and venous thrombosis, determine the extent and the gastrointestinal tract involved, and provide detailed information determining the subtype and the stage progression of the diseases, helping clinicians and surgeons with appropriate management. CT (Computed Tomography) can differentiate forms that are still susceptible to pharmacological or interventional treatment (NOM = non-operative management) from advanced disease with transmural necrosis in which a surgical approach is required. Knowledge of CT imaging patterns and corresponding vascular pathways is mandatory in emergency settings to reach a prompt and accurate diagnosis. The aims of this paper are 1. to provide technical information about the optimal CTA (CT Angiography) protocol; 2. to explain the CTA arterial and venous supply to the gastrointestinal tract and the relevant ischemic pattern; and 3. to describe vascular, bowel, and extraintestinal CT findings for the diagnosis of acute mesenteric ischemia.

[Epidemiology and diagnostics of mesenteric ischemia]

BACKGROUND

Mesenteric ischemia is a life-threatening condition with a complex etiology and diagnostics.

OBJECTIVE

Etiology, incidence, symptoms, and diagnostics of acute and chronic mesenteric ischemia.

MATERIAL AND METHODS

Literature search via PubMed with a focus on studies on the epidemiology and diagnostics of mesenteric ischemia and analysis of existing international guidelines.

RESULTS

The incidence of acute mesenteric ischemia is given as 0.63-12.9 per 100,000 people per year. There are no sufficiently reliable figures for chronic mesenteric ischemia, but an incidence of up to 3 per 100,000 inhabitants per year is generally assumed. The three-phase computed tomography has the highest diagnostic specificity and sensitivity.

CONCLUSION

In the presence of risk factors acute and chronic mesenteric ischemia should be considered as differential diagnoses in the presence of abdominal pain using three-phase computed tomography.

Probabilistic Prediction of Gastrointestinal Ischemia after Cardiothoracic Surgery

BACKGROUND

 Gastrointestinal ischemia (GIisch) is challenging to diagnose in patients after cardiothoracic surgery. Computed tomography angiography (CTA) carries substantial false-negative and false-positive rates. The aim of the study was to evaluate if a combination of readily available variables improves the diagnosis of GIisch after cardiothoracic surgery.

METHODS

 This retrospective study included patients receiving intensive care after cardiothoracic surgery. GIisch was confirmed by surgical and/or endoscopic findings. A GIisch prediction score was developed using the Spiegelhalter-Knill-Jones system in a training cohort then tested in a validation cohort (patients without obvious signs of GIisch on CTA).

RESULTS

 The training cohort comprised 125 consecutive patients with suspected GIisch in 2008 to 2019, including 85 with confirmed GIisch. CTA, performed in 92 patients, had a high false-negative rate of 17/60 (28%) and a lower false-positive rate of 7/32 (22%). The score included cardiopulmonary bypass, negatively associated with GIisch, and six variables positively associated with GIisch: intraoperative mean arterial pressure < 50 mm Hg, aspartate aminotransferase > 15 N, lactate increase in 24 hour > 20%, and 3 CTA findings, namely, bowel dilation, bowel wall thickening, and mesenteric vasoconstriction. The area under the receiver operating characteristic was 0.82 (95% confidence interval [CI], 0.51-0.93) in the training cohort and 0.82 (95% CI, 0.68-0.96) in the validation cohort (n = 34 patients). Reliability of the predicted probabilities was greatest for probabilities ≤ 30% or ≥ 70%.

CONCLUSION

 In patients receiving intensive care after cardiothoracic surgery, GIisch cannot be ruled out based solely on CTA findings. A scoring system combining CTA findings with other variables may improve the diagnosis of GIisch in this population.

Trends in population-based incidence, diagnostics, and mortality of acute superior mesenteric artery occlusion

Acute occlusion of the superior mesenteric artery (SMA) results in lethal intestinal ischemia. Results from two previous population-based studies in Malmö, Sweden, suggest a decreasing incidence of acute SMA occlusion. This study aimed to evaluate trends in the epidemiology of acute SMA occlusion in Malmö. The report was a retrospective population-based study conducted from 2014 to 2019 on patients with acute SMA occlusion residing in Malmö municipality. Patient data were retrieved from Skåne University Hospital and postmortem examinations. Epidemiological data were compared to those of the two earlier studies, in particular to the one conducted from 2000 to 2006. Sixteen patients with acute SMA occlusion resided in Malmö municipality. The incidence of acute SMA occlusion significantly decreased from 5.4/100,000 person-years to 0.8/100,000 person-years. The ratio of acute SMA occlusion to non-occlusive mesenteric ischemia (NOMI) decreased from 12.5:1 to 0.9:1 (p < 0.0001), the proportion of inhabitants aged 80 years or above in the population decreased from 6.0% to 4.3% (p < 0.0001), and the autopsy rate decreased from 25% to 14% (p < 0.0001). The in-hospital mortality rate decreased from 63% to 44% (p = 0.14). The incidence of acute SMA occlusion seems to have decreased significantly in Malmö, probably due to high-resolution computed tomography angiographies being available around the clock to distinguish acute SMA occlusion from NOMI, a reduced proportion of elderly individuals, improved control of medical risk factors, and a decrease in autopsy rates.

Insights into acute mesenteric ischaemia: an up-to-date, evidence-based review from a mesenteric stroke centre unit

Radiologists play a central role in the diagnostic and prognostic evaluation of patients with acute mesenteric ischaemia (AMI). Unfortunately, more than half of AMI patients undergo imaging with no prior suspicion of AMI, making identifying this disease even more difficult. A confirmed diagnosis of AMI is ideally made with dynamic contrast-enhanced CT but the diagnosis may be made on portal-venous phase images in appropriate clinical settings. AMI is diagnosed on CT based on the identification of vascular impairment and bowel ischaemic injury with no other cause. Moreover, radiologists must evaluate the probability of bowel necrosis, which will influence the treatment options.AMI is usually separated into different entities: arterial, venous, non-occlusive and ischaemic colitis. Arterial AMI can be occlusive or stenotic, the dominant causes being atherothrombosis, embolism and isolated superior mesenteric artery (SMA) dissection. The main finding in the bowel is decreased wall enhancement, and necrosis can be suspected when dilatation >25 mm is identified. Venous AMI is related to superior mesenteric vein (SMV) thrombosis as a result of a thrombophilic state (acquired or inherited), local injury (cancer, inflammation or trauma) or underlying SMV insufficiency. The dominant features in the bowel are hypoattenuating wall thickening with submucosal oedema. Decreased enhancement of the involved bowel suggests necrosis. Non-occlusive mesenteric ischaemia (NOMI) is related to impaired SMA flow following global hypoperfusion associated with low-flow states. There are numerous findings in the bowel characterised by diffuse extension. An absence of bowel enhancement and a thin bowel wall suggest necrosis in NOMI. Finally, ischaemic colitis is a sub-entity of arterial AMI and reflects localised colon ischaemia-reperfusion injury. The main CT finding is a thickened colon wall with fat stranding, which seems to be unrelated to SMA or inferior mesenteric artery lesions. A precise identification and description of vascular lesions, bowel involvement and features associated with transmural necrosis is needed to determine patient treatment and outcome.

An Update on Acute Mesenteric Ischemia

Acute mesenteric ischemia (AMI) is an uncommon yet highly lethal cause of acute abdomen in the emergency setting. Computed tomography (CT) imaging, in particular a biphasic protocol consisting of angiographic and venous phase scans, is widely used to corroborate non-specific clinical findings when suspicions of AMI are high. Techniques such as low kilovoltage peak scanning, dual energy acquisition, or a combined arterial/enteric phase can improve iodine conspicuity and evaluation of bowel enhancement. Biphasic CT with CT angiography is mandatory to directly assess for the 3 primary etiologies of AMI-arterial, venous, and non-occlusive mesenteric ischemia (NOMI), and the CT angiographic findings may be the first visible in the disease. In addition, numerous non-vascular CT findings have also been reported. Bowel wall thickening, mesenteric stranding, and ascites are common but non-specific findings that correlate poorly with disease severity. Pneumatosis intestinalis and portomesenteric venous gas, while not pathognomonic for ischemia, are highly specific in cases of high clinical suspicion. Bowel wall hypoenhancement is an early and specific sign but requires a protocol optimizing iodine conspicuity to confidently identify. Finally, intraperitoneal free air and solid organ infarcts are also highly specific ancillary findings in AMI. AMI occurs as a complication in 10% of small bowel obstruction (SBO) patients, and understanding imaging findings of ischemia in the context of SBO is necessary to aid in treatment planning and reduce over- and under-diagnosis of strangulation. Familiarity with the imaging features of ischemia by radiologists is vital to establish an early diagnosis before irreversible necrosis occurs.

[Computed tomography diagnostics of acute and chronic mesenteric ischemia]

BACKGRAUND

Chronic mesenteric ischemia is more often accompanied by clinical signs characteristic of colitis. Acute mesenteric ischemia, unlike chronic, is accompanied by nonspecific symptoms and is a serious disease that requires urgent diagnosis.

AIMS

The aim of the study was to evaluate the effectiveness of MSCT in the diagnosis of acute and chronic mesenteric ischemia based on our observations.

MATERIALS AND METHODS

The retrospective study included 135 patients with abdominalgia and suspected mesenteric ischemia who underwent multiphase CT of the abdominal cavity with intravenous bolus contrast enhancement. Group 1 included 105 patients with mesenteric ischemia; group 2 included 30, without confirmed mesenteric ischemia, with the presence of a symptom of mesenteric ischemia in the form of abdominalgia.

RESULTS

We studied 135 patients, including 105 patients with mesenteric ischemia, 59 women and 46 men of average age 60±14.9 years. The acute form of ischemia (58%) was determined 1.5 times more often than the chronic one. Occlusive and nonocclusive acute mesenteric ischemia occurred in equal proportions. Mesenteric arterial thrombosis was the cause of acute mesenteric ischemia in 23% of cases. Mesenteric venous thrombosis was the cause of chronic intestinal ischemia in 61%, in 5% - acute form. Mixed arterial-venous genesis of mesenteric ischemia was determined in 4% against the background of strangulation obstruction. Dunbar syndrome as a cause of chronic intestinal ischemia was diagnosed in 16%. Chronic ischemic enterocolitis accounted for 10% of all cases of mesenteric ischemia and 23% of chronic ischemia. Symptoms and symptom complexes characteristic of the studied series of diseases with acute or chronic mesenteric ischemia were delineated. Sensitivity, specificity and prognostic value of CT with intravenous bolus contrast enhancement in diagnostics of diseases accompanied by mesenteric ischemia reached 100%.

CONCLUSIONS

Multiphase CT of the abdominal cavity with bolus contrast enhancement is highly informative in the diagnosis of acute and chronic forms of mesenteric ischemia. Direct CT signs of impaired blood flow in the arteries or veins of the mesentery were indisputable. Indirect signs of mesenteric ischemia were aimed at a thorough analysis of the condition of mesenteric vessels.

Preoperative findings on non-specific CT in patients with primary acute intestinal ischemia: a case-control study

PURPOSE

Primary acute intestinal ischaemia (AII) is an abdominal catastrophe caused by intravascular obstruction of blood supply. It is difficult to diagnose. Computerized tomography (CT) scan is the modality of choice for diagnostic evaluation. Majority of previous studies have evaluated CT findings in patients where AII was suspected. However, unveiling the unique radiological findings also in not initially suspected AII patients, might lead to the timely management of AII patients, and is the aim of this study.

METHODS

In a single-center, retrospective case-control study, preoperative radiological findings from abdominal CT scans in 48 patients with primary AII were compared with 80 non-ischemic controls. Radiological findings were analyzed using multivariable logistical regression with adjustment for age and gender and reported as odds ratios (OR) with 95% confidence intervals (CI) and p values.

RESULTS

Thirty-nine (81%) cases with AII were referred to an abdominal CT scan without a specific clinical suspicion of AII. Three main radiological categories (intestinal wall pathology [OR 7.4, CI 2.3-24.0, p value < 0.001], gastrointestinal vessel pathology [OR 19.3, CI 4.6-80.5, p value < 0.001) and intestinal diameter [OR 4.7, CI 1.6-13.4, p value 0.004]) were significantly different in AII patients. Subgroup analysis implied that pneumatosis intestinalis, increased contrast enhancement in the bowel wall, inferior mesenteric artery arteriosclerosis and colonic contraction were predictors of AII.

CONCLUSION

Radiological changes within the intestinal wall, luminal diameter and gastrointestinal vessels are independent predictors of AII. Awareness of these radiological findings, therefore, plays a central role in patients with an indistinct clinical picture in early recognition and treatment of a life-threatening AII.

TRIAL REGISTRATION NUMBER

NCT04361110 (April 24, 2020), retrospectively registered.

Role of clinical data and multidetector computed tomography findings in acute superior mesenteric artery embolism

BACKGROUND

Superior mesenteric artery embolism (SMAE) has acute onset and fast progression, which seriously threatens the life of patients. Multidetector computed tomography (MDCT) is one of the most important diagnostic methods for SMAE, which plays an important role in the diagnosis and prognosis of SMAE.

AIM

To evaluate the value of combined clinical data and MDCT findings in the diagnosis of acute SMAE and predict the risk factors for SMAE-related death.

METHODS

Data from 53 SMAE patients who received abdominal MDCT multi-phase enhancement and superior mesenteric artery digital subtraction angiography examinations were collected. Univariate cox regression and multivariate cox model were used to analyze the correlation between death risk and clinical and computed tomography features in SMAE patients.

RESULTS

Univariate Cox regression model showed that intestinal wall thinning, intestinal wall pneumatosis, blood lactate > 2.1 mmol/L and blood pH < 7.35 increased the risk of death in patients with SMAE. After adjusting for age, sex, embolic involvement length and embolic distribution region, multivariate Cox regression model I showed that blood lactate > 2.1 mmol/L (HR = 5.26, 95%CI: 1.04-26.69, P = 0.045) and intestinal wall thinning (HR = 9.40, 95%CI: 1.05-83.46, P = 0.044) were significantly increases the risk of death in patients with SMAE.

CONCLUSION

For patients with SAME, increased blood lactate and intestinal wall thinning are the risk factors for death; hence, close monitoring may reduce the mortality rate. Clinical observation combined with MDCT signs can significantly improve SMAE diagnosis.

Dual-energy CT of acute bowel ischemia

Acute bowel ischemia is a condition with high mortality and requires rapid intervention to avoid catastrophic outcomes. Swift and accurate imaging diagnosis is essential because clinical findings are commonly nonspecific. Conventional contrast enhanced CT of the abdomen has been the imaging modality of choice to evaluate suspected acute bowel ischemia. However, subtlety of image findings and lack of non-contrast or arterial phase images can make correct diagnosis challenging. Dual-energy CT provides valuable information toward assessing bowel ischemia. Dual-energy CT exploits the differential X-ray attenuation at two different photon energy levels to characterize the composition of tissues and reveal the presence or absence of faint intravenous iodinated contrast to improve reader confidence in detecting subtle bowel wall enhancement. With the same underlying technique, virtual non-contrast images can help to show non-enhancing hyperdense hemorrhage of the bowel wall in intravenous contrast-enhanced scans without the need to acquire actual non-contrast scans. Dual-energy CT derived low photon energy (keV) virtual monoenergetic images emphasize iodine contrast and provide CT angiography-like images from portal venous phase scans to better evaluate abdominal arterial patency. In Summary, dual-energy CT aids diagnosing acute bowel ischemia in multiple ways, including improving visualization of the bowel wall and mesenteric vasculature, revealing intramural hemorrhage in contrast enhanced scans, or possibly reducing intravenous contrast dose.

The role of adropin, HIF-1α and apelin biomarkers in the diagnosis of acute mesentaric ischemia

OBJECTIVE

The absence of a specific biomarker for acute mesenteric ischemia diagnosis results in a delay in diagnosis and treatment, as well as a high mortality rate. The current research examined whether the proteins adropin, HIF-1α, and apelin may be used to help in the early detection of acute mesenteric ischemia.

MATERIALS AND METHODS

A total of 20 patients with acute mesenteric ischemia, 20 patients with abdominal pain, and 20 healthy controls were included in the study. The levels of adropin, HIF-1, and apelin in the serum were determined using the ELISA method.

RESULTS

Adropin concentrations were significantly higher in the acute mesenteric ischemia group than in the abdominal pain and healthy control groups (p < 0.05). HIF-1α levels were considerably greater in patients with acute mesenteric ischemia compared to both the abdominal pain group and the healthy control group (p < 0.05). There was no difference in apelin levels between the acute mesenteric ischemia and abdominal pain groups (p > 0.05). HIF-1α was found to be moderate (AUC: 0.705) and adropin was found to be a weak biomarker (AUC: 0.692) in the ROC analysis for acute mesenteric ischemia.

CONCLUSION

In this study of 20 patients with acute mesenteric ischemia, we found adropin and HIF-1α levels to be increased compared to patients with abdominal pain who did not have acute mesenteric ischemia.

Colon ischemia: A comprehensive review

The clinical and endoscopic features of colon ischemia (CI) are non-specific. CI is correctly identified at the time of presentation in only 9% of patients is. The true incidence is likely underestimated because many mild cases resolve spontaneously without medical treatment. Furthermore, since most cases of CI are transient, and no specific cause is detected they are often considered to be "idiopathic". In the setting of severe CI correct diagnosis and prompt recognition and therapy as well as identification of underlying causes are crucial for a favourable outcome. Although less severe, mild cases may present with similar symptoms, the prognosis and management are completely different and managed conservatively rather than with surgery. Unfortunately, data from most studies and current guidelines do not provide recommendations on the long-term management of CI or about the need for endoscopic follow-up to detect the development chronic, recurrent and/or ischemic colonic strictures. In this review, we focus on the definition of CI, its aetiology, and patterns of presentation. We highlight the pharmacological and/or endoscopic management as determined severity of disease that allow for improved outcomes. Prompt recognition and treatment using a multidisciplinary approach are essential for successful management of severe CI because mortality rates are significantly higher when the diagnosis is delayed.

Mesenteric Vessel Thrombosis Treatment Experience

BACKGROUND: One of the most serious diseases among all emergency abdominal pathology is an acute violation of the mesenteric blood circulation. The rapid development of intestinal ischemia results in its infarction and necrosis. AIM: The study aims to assess the survival rate of patients with mesenteric vascular thrombosis, taking into account, the predictor characteristics influence of disease development factors. METHODS: The study presents a retrospective analysis of mesenteric vascular thrombosis clinical cases for 2016–2019. During this period, there were 147 patients with an established diagnosis at the Irkutsk Clinical Hospital No. 1, 21 of them met the study criteria. RESULTS: According to the type of thrombosis, there were two groups – occlusive (Group I, n = 11) and non occlusive (Group II, n = 10). Four patients (36.3%) of Group I and 7 patients (70%) of Group II (p = 0.388) recovered from the disease. Three patients (27.2%) of Group I and 4 patients (40%) of Group II (p = 0.662) received conservative therapy, 2 of them (66.6%) in Group I and 4 (100%) in Group II (p = 0.724) recovered from the disease. In addition, the authors performed a mortality assessment, according to the timing of the visit to a medical institution. Four (50%) out of eight patients who applied in the first 12 h, 2 (66%) out of three – in the first 12–24 h, and 5 (50%) out of 10 for more than 24 h of illness had a positive treatment result in the combined group. CONCLUSION: The patients over 70 years old with peritoneal symptoms and established intestinal necrosis have an extremely unfavorable prognosis. The primary mesenteric vessel thrombosis with additional contrast angiography still gives a moderate treatment prognosis.

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.

[Is acute mesenteric ischemia incurable situation? The current state of the problem]

Mortality rates in acute mesenteric ischemia remain at an extremely high level for many decades. Early diagnosis and selection of the optimal method of revascularization are among the ways to optimize tactics. The diagnostic study of choice is CT angiography. Its active and systemic use can help to detect ischemia at the reversible stage. The article examines in detail the indications for the application of this diagnostic study. The question of preference for the revascularization method remains debatable. The arguments of proponents of open and endovascular interventions on mesenteric vessels are presented. Other, still unresolved tactical issues are also considered, such as indications for re-operations and application of the principles of damage control tactics.

Chronic mesenteric ischemia: Clinical practice guidelines from the Society for Vascular Surgery

BACKGROUND

Chronic mesenteric ischemia (CMI) results from the inability to achieve adequate postprandial intestinal blood flow, usually from atherosclerotic occlusive disease at the origins of the mesenteric vessels. Patients typically present with postprandial pain, food fear, and weight loss, although they can present with acute mesenteric ischemia and bowel infarction. The diagnosis requires a combination of the appropriate clinical symptoms and significant mesenteric artery occlusive disease, although it is often delayed given the spectrum of gastrointestinal disorders associated with abdominal pain and weight loss. The treatment goals include relieving the presenting symptoms, preventing progression to acute mesenteric ischemia, and improving overall quality of life. These practice guidelines were developed to provide the best possible evidence for the diagnosis and treatment of patients with CMI from atherosclerosis.

METHODS

The Society for Vascular Surgery established a committee composed of vascular surgeons and individuals experienced with evidence-based reviews. The committee focused on six specific areas, including the diagnostic evaluation, indications for treatment, choice of treatment, perioperative evaluation, endovascular/open revascularization, and surveillance/remediation. A formal systematic review was performed by the evidence team to identify the optimal technique for revascularization. Specific practice recommendations were developed using the Grading of Recommendations Assessment, Development, and Evaluation system based on review of literature, the strength of the data, and consensus.

RESULTS

Patients with symptoms consistent with CMI should undergo an expedited workup, including a computed tomography arteriogram, to exclude other potential causes. The diagnosis is supported by significant arterial occlusive disease in the mesenteric vessels, particularly the superior mesenteric artery. Treatment requires revascularization with the primary target being the superior mesenteric artery. Endovascular revascularization with a balloon-expandable covered intraluminal stent is the recommended initial treatment with open repair reserved for select younger patients and those who are not endovascular candidates. Long-term follow-up and surveillance are recommended after revascularization and for asymptomatic patients with severe mesenteric occlusive disease. Patient with recurrent symptoms after revascularization owing to recurrent stenoses should be treated with an endovascular-first approach, similar to the de novo lesion.

CONCLUSIONS

These practice guidelines were developed based on the best available evidence. They should help to optimize the care of patients with CMI. Multiple areas for future research were identified.

Contrast-Enhanced CT for the Diagnosis of Acute Mesenteric Ischemia

OBJECTIVE. The purpose of this article is to provide an overview of the diagnostic and prognostic roles of CT in the management of acute mesenteric ischemia. CONCLUSION. Acute mesenteric ischemia is defined as inadequate blood supply to the gastrointestinal tract resulting in ischemic and inflammatory injury. The prognosis is poor without treatment. Contrast-enhanced CT has become the cornerstone of diagnosis to identify features of vascular disorders and of intestinal ischemic injury and to visualize bowel necrosis.

Review Article: Mesenteric Ischemia

PURPOSE OF REVIEW

Mesenteric ischemia (MI), both acute (AMI) and chronic (CMI), is a challenging diagnosis to make, and early diagnosis and treatment are vital to improve outcomes. This manuscript summarizes the most up to date information on diagnosis and treatment of these disorders.

RECENT FINDINGS

There have been several significant advancements in the computed tomography (CT) diagnostic imaging as well as medical and endovascular management of AMI and CMI. In appropriate populations, endovascular interventions appear superior to open surgical management with lower mortality, morbidity, and cost of care. Efficient clinical identification and targeted testing are essential to diagnose AMI and CMI. Aggressive resuscitation and early endovascular (or in select cases, surgical) intervention improve outcomes in those with AMI. In those with CMI, considering this on the differential diagnosis and imaging appropriately can identify those that might benefit from intervention and halt progression to acute episodes.

Split-bolus CTA for mesenteric ischemia with a single scan opacifying arterial and mesenteric venous systems

OBJECTIVE

To evaluate the diagnostic accuracy of split-bolus single-scan computed tomography angiography (CTA) protocol for evaluation of acute mesenteric ischemia and alternate diagnoses.

MATERIALS AND METHODS

In this IRB-approved, HIPAA-compliant retrospective study, consecutive patients from 21 October 2016 to 6 May 2018 evaluated for mesenteric ischemia with split-bolus CTA (a single scan in concurrent arterial and portal venous phase) in a single tertiary academic institution were included. Intravenous contrast was administered on weight-based basis. Quantitative and qualitative assessments of superior mesenteric artery (SMA) and superior mesenteric vein (SMV) attenuation and patency were performed by two independent reviewers. CT imaging findings were correlated with clinical reference outcomes.

RESULTS

One hundred fifty-four patients (age 66.3 ± 14.1 years, BMI 27.3 ± 6, 86 (56%) female) were included. CTA studies were performed with a volumetric CT dose index of 15.9 ± 5.5 mSv and dose length product of 1042.9 ± 389.4 mGy cm. Average intravenous contrast volume administered was 164.3 ± 12.1 cc. SMA attenuation was 263.6 ± 92.4HU, SMV was 190 ± 50.2HU. Qualitative assessment of SMA and SMV showed good opacification in all patients. 17/154 (11%) patients were diagnosed on CT with mesenteric ischemia; in 6/154 (4%), CTA studies were indeterminate; in 131/154 (85%), CTA confidently ruled out mesenteric ischemia. Alternate diagnoses were made in 38/154 (25%) patients. Using composite clinical outcomes as a reference standard, sensitivity of split-bolus CTA protocol for diagnosis of mesenteric ischemia is 100% (95% CI 79-100%), and specificity is 99% (95% CI 96-100%).

CONCLUSIONS

Split-bolus CTA has high sensitivity and specificity for diagnosis of acute mesenteric ischemia.

KEY POINTS

• Split-bolus CTA protocol for mesenteric ischemia has great diagnostic accuracy with lower radiation exposure and fewer images to interpret compared with standard multiphasic CTA.

Early laparoscopic exploration for acute mesenteric ischemia after cardiac surgery

Acute mesenteric ischemia (AMI) after cardiac surgery is a rare but fatal complication. Early diagnosis and intervention can be lifesaving. We report two cases of patients who underwent early diagnostic laparoscopy for suspicious AMI after cardiac surgery and demonstrated favorable outcomes. An 83-year-old male with severe left ventricular dysfunction underwent off-pump coronary artery bypass grafting. Severe ileus with gaseous distension of the small bowel was developed on the 3rd postoperative day and computed tomographic angiography (CTA) showed pneumatosis intestinalis of small bowel suggestive of AMI. An immediate bedside laparoscopy was performed and it showed preserved perfusion of small bowel. He recovered without complication under supportive medical management. Another 69-year-old male who underwent aortic valve replacement complained of whole abdominal tenderness with severe distension on the 3rd postoperative day. The CTA found segmental non-enhancing bowel wall with air bubbles suggestive of AMI with possible microperforation. A diagnostic laparoscopy demonstrated small-bowel infarction with pus-like fluid collection in the peritoneal cavity. The operation was converted to laparotomy and complete resection of ischemic segments of small bowel was done. He recovered well without any other complications and discharged home on the 35th postoperative day.

D-dimer: Preanalytical, analytical, postanalytical variables, and clinical applications

D-dimer is a soluble fibrin degradation product deriving from the plasmin-mediated degradation of cross-linked fibrin. D-dimer can hence be considered a biomarker of activation of coagulation and fibrinolysis, and it is routinely used for ruling out venous thromboembolism (VTE). D-dimer is increasingly used to assess the risk of VTE recurrence and to help define the optimal duration of anticoagulation treatment in patients with VTE, for diagnosing disseminated intravascular coagulation, and for screening medical patients at increased risk of VTE. This review is aimed at (1) revising the definition of D-dimer; (2) discussing preanalytical variables affecting the measurement of D-dimer; (3) reviewing and comparing assay performance and some postanalytical variables (e.g. different units and age-adjusted cutoffs); and (4) discussing the use of D-dimer measurement across different clinical settings.

Predictive Risk Factors of Intestinal Necrosis in Patients with Mesenteric Venous Thrombosis: Retrospective Study from a Single Center

PURPOSES

Mesenteric venous thrombosis (MVT) is a serious condition. The current study aimed to identify risk factors of intestinal necrosis (IN) in patients with MVT to predict the onset of patients.

METHODS

Data pertaining to patients diagnosed with MVT between 2014 and May 2018 were reviewed. Patients' characteristics and risk factors of IN were assessed.

RESULTS

Seventy-eight patients were included in our study, of whom all cases were diagnosed as superior mesenteric venous thrombosis. There were fifty-eight cases (74%) with intestinal necrosis and twenty cases (26%) without intestinal necrosis. Multivariate analysis of factors associated with IN was organ failure (odds ratio (OR): 4.1; 95% confidence interval (95%CI): 1.26-8.59; P=0.028), elevated serum lactate (OR:3.6; 95% CI: 1.51-5.47; P=0.024), bowel loop dilation on computerized tomography (CT) scan (OR: 2.8; 95% CI: 1.32-7.23; P=0.031), and the time between onset of symptoms and operation (OR: 4.8; 95% CI: 1.36-9.89; P=0.012). Area under the receiver operating characteristics curve for the diagnosis of IN with MVT was 0.901 (95%CI: 0.809-0.993; P=0.000) depending on the different number of predictive factors.

CONCLUSION

Predictive risk factors for IN with MVT were organ failure, elevated serum lactate level, bowel loop dilation on CT, and the time between onset of symptoms and operation. However, this result is from a retrospective study and further long-term, large-sample prospective studies are required to confirm this finding.

Acute mesenteric ischaemia: a pictorial review

Abstract

Acute mesenteric ischaemia (AMI) is an uncommon cause of acute hospital admission with high mortality rates (50–90%) that requires early diagnosis and treatment. With the increase in average life expectancy, AMI represents one of the most threatening abdominal conditions in elderly patients. Untreated, AMI will cause mesenteric infarction, intestinal necrosis, an overwhelming inflammatory response and death. Early intervention can reverse this process leading to a full recovery, but the diagnosis of AMI is difficult. The failure to recognise AMI before intestinal necrosis has developed is responsible for the high mortality of the disease. Unfortunately, common CT findings in bowel ischaemia are not specific. Therefore, it is often a combination of nonspecific clinical, laboratory and radiological findings that helps most in the correct interpretation of CT findings. The purpose of this article is to provide an overview of the anatomy, physiology of mesenteric perfusion and discussions of causes, pathogenesis and CT findings in various types of acute bowel ischaemia. Familiarity with various imaging features of mesenteric injury is essential to make a timely diagnosis that will lead to improved patient outcomes.

Teaching Points

• AMI is a potentially life-threatening disorder whose prognosis depends on early recognition, accurate diagnosis and timely intervention.

• Arterial inflow occlusion due to thrombosis or embolisation is the most common cause of AMI.

• Four aetiological types of AMI have been associated with different characteristics and risk factors (EAMI, TAMI, VAMI and NOMI).

• Physical examination and laboratory findings are not sensitive or specific for diagnosing AMI; therefore, MDCT is still the first-line imaging method in suspected AMI.

• Although a number of scoring systems for prognosis have been proposed, these have not been validated in large-scale studies.

Inter-reader agreement of CT features of acute mesenteric ischemia

PURPOSE

To evaluate the inter-reader agreement of the CT features of acute mesenteric ischemia (AMI).

METHODS

Between 2006 and 2014, 109 patients (57 men, 52%, mean age 50 years old [17-83]) admitted to our institution with a diagnosis of AMI were included. CT scans (42% were initially performed in our institution) were reviewed by two abdominal radiologists. Inter-observer agreement of the imaging features of vascular insufficiency and bowel ischemia was assessed by the percentage of agreement and the kappa value.

RESULTS

The final population included, Inter-observer agreement varied according to the different features (κ = 0.25-0.98). Inter-observer agreement for decreased/absent bowel wall enhancement was moderate (κ = 0.52), but was almost perfect (κ = 0.82) in the 47 patients (43%) with both unenhanced and arterial-phase images without positive oral contrast agent and excellent CT images quality.

CONCLUSION

Inter-reader agreement was moderate to substantial for most CT features of AMI. Multiphasic CT scan protocol, including unenhanced, arterial phase and venous phase images, without positive oral contrast agent, and excellent CT images quality improve inter-observer agreement of imaging features of AMI, especially for decreased/absent bowel wall enhancement, and should be performed in patients with suspected AMI.

ACR Appropriateness Criteria® Radiologic Management of Mesenteric Ischemia

Mesenteric vascular insufficiency is a serious medical condition that may lead to bowel infarction, morbidity, and mortality that may approach 50%. Recommended therapy for acute mesenteric ischemia includes aspiration embolectomy, transcatheter thrombolysis, and angioplasty with or without stenting for the treatment of underlying arterial stenosis. Nonocclusive mesenteric ischemia may respond to transarterial infusion of vasodilators such as nitroglycerin, papaverine, glucagon, and prostaglandin E1. Recommended therapy for chronic mesenteric ischemia includes angioplasty with or without stent placement and, if an endovascular approach is not possible, surgical bypass or endarterectomy. The diagnosis of median arcuate ligament syndrome is controversial, but surgical release may be appropriate depending on the clinical situation. Venous mesenteric ischemia may respond to systemic anticoagulation alone. Transhepatic or transjugular superior mesenteric vein catheterization and thrombolytic infusion can be offered depending on the severity of symptoms, condition of the patient, and response to systemic anticoagulation. Adjunct transjugular intrahepatic portosystemic shunt creation can be considered for outflow improvement. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

The role of multislice computed tomography (MSCT) angiography in the diagnosis and therapy of non-occlusive mesenteric ischemia (NOMI): Could MSCT replace DSA in diagnosis?

Objectives

Evaluation of multislice-CT (MSCT) during diagnosis and therapeutic decision-making in patients with suspected non-occlusive mesenteric ischemia (NOMI).

Methods

Retrospective, institutional review board-approved study of 30 patients (20 men, 10 women, mean age 64.6±14.2 years, range 24–87 years) undergoing biphasic abdominal MSCT followed by digital subtraction angiography (DSA) due to suspected NOMI. MSCT and DSA were qualitatively and quantitatively evaluated independently by two radiologists with respect to the possible diagnosis of NOMI. MSCT analysis included quantitative measurements, qualitative evaluation of contrast enhancement and assessment of secondary findings (bowel wall thickening, hypo-enhancement, intestinal pneumatosis). MSCT diagnosis and secondary findings were compared against DSA diagnosis.

Results

NOMI was diagnosed in a total of n = 28 patients. No differences were found when comparing the R1-rated MSCT diagnosis (p = 0.09) to the “gold standard”, while MSCT diagnosis was slightly inferior with R2 (p = 0.02). With R1, vessel-associated parameters revealed the best correlation, i.e. qualitative vessel width (r = -0.39;p = 0.03) and vessel contrast (r = 0.45;p = 0.01). Moderate correlations were found for quantitative vessel diameters in the middle segments (r = -0.48,p = 0.01), increasing to almost high correlations in the distal (r = -0.66;p<0.00001) superior mesenteric artery (SMA) segments. No significant correlation was apparent from secondary findings.

Conclusions

MSCT is an appropriate non-invasive method for diagnosing NOMI and leads to adequate and immediate therapeutic stratification.

Non-occlusive mesenteric ischaemia: CT findings, clinical outcomes and assessment of the diameter of the superior mesenteric artery

OBJECTIVE

Review of the experience of a tertiary care centre for almost 10 years in the CT diagnosis of non-occlusive mesenteric ischaemia (NOMI). Analysis of CT findings, correlation with clinical outcomes and evaluation of the usefulness of measuring the superior mesenteric artery (SMA) diameter for the diagnosis of NOMI.

METHODS

106 patients were diagnosed with NOMI in a biphasic CT examination from 2008 to 2017 in our hospital. Clinical outcomes and CT findings were reviewed. In 55 patients, the diameter of the SMA was compared with a previous CT scan where NOMI was not the diagnosis, and statistical analysis using paired t-test was performed.

RESULTS

81 patients (76%) had findings consistent with small bowel ischaemia and the ileum was the segment most commonly involved (47%). Lack of wall enhancement, pneumoperitoneum, pneumatosis intestinalis and portal venous gas were all considered signs of bowel necrosis and surgery was performed promptly. 70 patients had signs of vascular narrowing of the SMA branches and in the 55 cases with a previous CT scan, there were statistically significant differences regarding the SMA diameter with a mean reduction of the artery calibre and standard deviation of 1.93 ± 1.1 mm between the NOMI and non-NOMI scans (p < 0.001).

CONCLUSION

Acknowledgment of characteristic bowel necrosis CT findings is crucial for determining the therapeutic attitude and the use of previous CT scans to compare the SMA diameter may help the radiologist to achieve an early diagnosis of NOMI in an often critically ill patient population. Advances in knowledge: Diagnosis of NOMI can be difficult in cases of partial mural ischaemia, thus objective data (diameter of the SMA) should be useful for the radiologist to include NOMI as the first diagnostic option in the differential diagnosis.

Accuracy of using serum D-dimer for diagnosis of acute intestinal ischemia: A meta-analysis

OBJECTIVE

The purpose of this meta-analysis is to comprehensively assess the accuracy of serum D-dimer for the diagnosis of acute intestinal ischemia.

METHODS

Diagnostic studies of D-dimer for accurate diagnosis of acute intestinal ischemia were extracted from 6 databases, and prospective and retrospective studies that provided adequate data on sensitivity and specificity were included here. Sensitivity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were calculated. The overall diagnostic performance of D-dimer was assessed by plotting a summary receiver operating characteristic curve (SROC) and calculating the area under the curve (AUC).

RESULTS

A total of 1300 patients with suspected acute intestinal ischemia from 12 studies met the inclusion criteria. The combined sensitivity, specificity, PLR, NLR, and DOR were 0.94 (95% CI: 0.87-0.97), 0.50 (95% CI: 0.40-0.61), 1.9 (95% CI: 1.5-2.3), 0.12 (95% CI: 0.05-0.26), and 16 (95% CI: 7-39), respectively. The AUC was 0.81 (95% CI: 0.78-0.84).

CONCLUSION

The results of this meta-analysis suggested that plasma D-dimer detection might be a useful means of identifying patients with acute intestinal ischemia of the abdomen.

Vascular imaging of the mesenteric vasculature

Imaging of the mesenteric vasculature is crucial in diagnosing vascular disease of the gastro-intestinal tract such as acute or chronic mesenteric ischemia caused by arterial stenosis, embolism or thrombosis, mesenteric vein thrombosis and mesenteric aneurysm or dissection. The reference standard for imaging of the mesenteric vasculature is digital subtraction angiography. However, modalities as duplex ultrasonography, computed tomography angiography and magnetic resonance angiography are developing rapidly and may provide accurate imaging non-invasively. This review provides an up-to-date overview of the anatomic resolution, clinical application, emerging techniques and future perspectives of these four radiological modalities for imaging of the mesenteric vasculature.

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.

The optimal monochromatic spectral computed tomographic imaging plus adaptive statistical iterative reconstruction algorithm can improve the superior mesenteric vessel image quality

OBJECTIVE

To investigate the effect of the optimal monochromatic spectral computed tomography (CT) plus adaptive statistical iterative reconstruction on the improvement of the image quality of the superior mesenteric artery and vein.

MATERIALS AND METHODS

The gemstone spectral CT angiographic data of 25 patients were reconstructed in the following three groups: 70KeV, the optimal monochromatic imaging, and the optimal monochromatic plus 40%iterative reconstruction mode. The CT value, image noises (IN), background CT value and noises, contrast-to-noise ratio (CNR), signal-to-noise ratio (SNR) and image scores of the vessels and surrounding tissues were analyzed.

RESULTS

In the 70KeV, the optimal monochromatic and the optimal monochromatic images plus 40% iterative reconstruction group, the mean scores of image quality were 3.86, 4.24 and 4.25 for the superior mesenteric artery and 3.46, 3.78 and 3.81 for the superior mesenteric vein, respectively. The image quality scores for the optimal monochromatic and the optimal monochromatic plus 40% iterative reconstruction groups were significantly greater than for the 70KeV group (P<0.05). The vascular CT value, image noise, background noise, CNR and SNR were significantly (P<0.001) greater in the optimal monochromatic and the optimal monochromatic images plus 40% iterative reconstruction group than in the 70KeV group. The optimal monochromatic plus 40% iterative reconstruction group had significantly (P<0.05) lower image and background noise but higher CNR and SNR than the other two groups.

CONCLUSION

The optimal monochromatic imaging combined with 40% iterative reconstruction using low-contrast agent dosage and low injection rate can significantly improve the image quality of the superior mesenteric artery and vein.

An investigation of bedside laparoscopy in the ICU for cases of non-occlusive mesenteric ischemia

BACKGROUND

Acute mesenteric ischemia is a rare affection with high related mortality. NOMI presents the most important diagnostic problems and is related with the higher risk of white laparotomy. This study wants to give a contribution for the validation of laparoscopic approach in case of NOMI.

METHODS

Thirty-two consecutive patients were admitted in last 10 years in ICU of Paolo Giaccone University Hospital of Palermo for AMI. Diagnosis was obtained by multislice CT and selective angiography was done if clinical conditions were permissive. If necrosis was already present or suspected, surgical approach was done. Endovascular or surgical embolectomy was performed when necessary. Twenty NOMI patients underwent medical treatment performing laparoscopy 24 h later to verify the evolution of AMI. A three-port technique was used. In all patients we performed a bed side procedure 48-72 h later in both non-resected and resected group.

RESULTS

In 14 up 20 case of NOMI the disease was extended throughout the splanchnic district, in 6 patients it involved the ileum and the colon; after a first look, only 6 patients underwent resection. One patient died 35 h after diagnosis of NOMI. The second look, 48 h later, demonstrated 4 infarction recurrences in the group of resected patients and onset signs of necrosis in 5 patients of non-resected group. A total of 15 resections were performed on 11 patients. Mortality rate was 6/20-30% but it was much higher in resected group (5/11-45,5%). Non-therapeutic laparotomy was avoided in 9/20 patients and in this group mortality rate was 1/9-11%. No morbidity was recorded related to laparoscopic procedure.

CONCLUSIONS

Laparoscopy could be a feasible and safety surgical approach for management of patient with NOMI. Our retrospective study demonstrates that laparoscopy don't increase morbidity, reduce mortality avoiding non-therapeutic laparotomy.

Plasma citrulline measurement in the diagnosis of acute mesenteric ischaemia

BACKGROUND

The differential diagnosis in acute mesenteric ischaemia (AMI) is essential and sometimes life-saving. A marker for early diagnosis is lacking. Citrulline is an amino acid mainly synthesized by small bowel enterocytes from glutamine. In this study, we aimed to evaluate the diagnostic and prognostic values of citrulline with those of the D-dimer in patients with AMI.

METHODS

The patients were divided into two groups; group 1: patients with acute abdominal findings which were attributed preoperatively to AMI, and group 2: patients with acute abdominal findings which were attributed preoperatively to causes other than AMI. All patients underwent surgical exploration. Blood samples were taken before surgery. The demographic features, laboratory examinations, citrulline concentration, D-dimer level and surgical findings were evaluated.

RESULTS

Overall, 48 patients were enrolled in the study. AMI was diagnosed in 23 of the 48 patients. There was no significant difference between the groups with regard to gender, leucocyte count and creatinine levels but group 1 was significantly older than group 2. Citrulline, D-dimer and lactate levels were also significantly higher in group 1. Age, lactate, D-dimer and citrulline levels were statistically significant for mortality. The most significant factor was increased lactate level at admission.

CONCLUSION

Plasma citrulline level may be helpful in the diagnosis of patients with AMI.

ESTES guidelines: acute mesenteric ischaemia

PURPOSE

Acute mesenteric ischaemia (AMI) accounts for about 1:1000 acute hospital admissions. Untreated, AMI will cause mesenteric infarction, intestinal necrosis, an overwhelming inflammatory response and death. Early intervention can halt and reverse this process leading to a full recovery, but the diagnosis of AMI is difficult and failure to recognize AMI before intestinal necrosis has developed is responsible for the high mortality of the disease. Early diagnosis and prompt treatment are the goals of modern therapy, but there are no randomized controlled trials to guide treatment and the published literature contains a high ratio of reviews to original data. Much of that data comes from case reports and often small, retrospective series with no clearly defined treatment criteria.

METHODS

A study group of the European Society for Trauma and Emergency Surgery (ESTES) was formed in 2013 with the aim of developing guidelines for the management of AMI. A comprehensive literature search was performed using the Medical Subject Heading (MeSH) thesaurus keywords "mesenteric ischaemia", "bowel ischaemia" and "bowel infarction". The bibliographies of relevant articles were screened for additional publications. After an initial systematic review of the literature by the whole group, a steering group formulated questions using a modified Delphi process. The evidence was then reviewed to answer these questions, and recommendations formulated and agreed by the whole group.

RESULTS

The resultant recommendations are presented in this paper.

CONCLUSIONS

The aim of these guidelines is to provide recommendations for practice that will lead to improved outcomes for patients.

A New Approach Using Manganese-Enhanced MRI to Diagnose Acute Mesenteric Ischemia in a Rabbit Model: Initial Experience

PURPOSE

Manganese-enhanced MRI (MEMRI) has been applied to a wide range of biological and disease research. The purpose of the study was to use MEMRI to diagnose the acute mesenteric ischemia (AMI).

METHODS

The institutional experimental animal ethics committee approved this study. To optimize the dose of Mn(2+) infusion, a dose-dependent curve was obtained using Mn(2+)-enhanced T 1 map MRI by an intravenous infusion 2.5-20 nmol/g body weight (BW) of 50 nmol/L MnCl2. The eighteen animals were divided into control, sham-operated, and AMI groups. AMI models were performed by ligating the superior mesenteric artery (SMA). T 1 values were measured on T 1 maps in regions of the small intestinal wall and relaxation rate (ΔR 1) was calculated.

RESULTS

A nonlinear relationship between infused MnCl2 solution dose and increase in small intestinal wall ΔR 1 was observed. Control animal exhibited significant Mn(2+) clearance over time at the dose of 15 nmol/g BW. In the AMI model, ΔR 1 values (0.95 ± 0.13) in the small intestinal wall were significantly lower than in control group (2.05 ± 0.19) after Mn(2+) infusion (P < 0.01).

CONCLUSION

The data suggest that MEMRI shows potential as a diagnostic technique that is directly sensitive to the poor or absent perfusion in AMI.

Detecting acute mesenteric ischemia in CT of the acute abdomen is dependent on clinical suspicion: Review of 95 consecutive patients

OBJECTIVES

(1) To evaluate the ability of emergency room radiologists to detect acute mesenteric ischemia (AMI) from computed tomography (CT) images in patients with acute abdominal pain. (2) To identify factors affecting radiologists' performance in the CT interpretation and patient outcome.

MATERIALS AND METHODS

A retrospective study of 95 consecutive patients treated for 97 AMI events between 2009 and 2013 was carried out. The etiology of AMI was embolism in 24 (25%), atherosclerotic vascular disease (ASVD) in 39 (40%), non-obstructive mesenteric ischemia (NOMI) in 25 (26%), and mesenteric venous thrombosis (MVT) in nine (9%) cases. The protocols, referrals and initial radiology reports of the abdominal CTs were analyzed. The CT studies were further scrutinized for vascular and intestinal findings.

RESULTS

The referring clinician had suspected AMI in 30 (31%) cases prior to imaging. The crucial findings of AMI had been stated in 97% of the radiology reports if the clinician had mentioned AMI suspicion in the referral; if not, the corresponding rate was 81% (p=0.04). Patients without suspicion of AMI prior to CT were more prone to undergo bowel resection. CT protocol was optimal for AMI (with contrast enhancement in arterial and venous phases) in only 34 (35%) cases. Intestinal findings were more difficult to detect than vascular findings. Vascular findings were retrospectively detectable in 92% of cases with embolism and 100% in ASVD and MVT. Some evidence of intestinal abnormality was retrospectively found in the CT findings in 92%, 100%, 100% and 67% of cases with embolism, ASVD, NOMI and MVT, respectively.

CONCLUSIONS

AMI is underdiagnosed in the CT of the acute abdomen if there is no clinical suspicion.

[Nonocclusive mesenteric ischemia (NOMI): Modern diagnostic and therapeutic interventional strategies from a radiological point of view]

BACKGROUND

Nonocclusive mesenteric ischemia (NOMI), a rare form of mesenteric perfusion, is associated with a high mortality rate, especially when the diagnosis is delayed.

OBJECTIVE

Optimizing the diagnostic workup and the use of modern diagnostic possibilities are needed to reduce mortality and morbidity.

RECOMMENDED APPROACH

Recent studies recommend not yet standardized integration of computed tomography into the diagnostic workup. This paper gives an overview of the current data for the diagnosis of NOMI.

Peritoneal Potassium and pH Measurement in Early Diagnosis of Acute Mesenteric Ischemia in Rats

Background:

In contemporary practice, acute mesenteric ischemia (AMI) remains a serious cause of morbidity and mortality in abdominal emergencies.

Objectives:

We report the measurement of peritoneal fluid potassium and pH on a small series of rats that developed extensive AMI following the surgical ligation of superior mesenteric vessels and compare the results with control groups.

Materials and Methods:

A total of 32 rats were used in our study. They were divided into four groups with eight rats in each one and received following treatments: group I (G-I), 60-minute controls; group II (G-II), 120-minute controls; group III (G-III), 60-minute cases; and group IV (G-IV), 120-minute cases. In case groups, the small bowel mesenteric root was double-ligated and an arrow single-lumen central venous catheter was passed through the skin to the peritoneum. In control groups, the catheter was placed without any intervention. Postoperatively, peritoneal lavage was performed at 60 (G-I, G-III) and 120 minutes (G-II, G-IV).

Results:

The mean peritoneal potassium values were 1.3 ± 0.3, 1.97 ± 1.06, 2.14 ± 0.89, and 3.28 ± 0.66 mmol/L in G-I, G-II, G-III, and G-IV, respectively. There were significant differences between G-III and G-IV (P = 0.002), between G-I and G-III (P = 0.024), and between G-II and G-IV (P = 0.001). The mean values of peritoneal fluid pH were 7.1 ± 0.26, 6.82 ± 0.22, 6.66 ± 0.16, and 6.78 ± 0.04 in G-I, G-II, G-III, and G-IV, respectively, which indicated significant differences between G-I and G-III (P = 0.001) and between G-II and G-IV (P = 0.018). There was a significant correlation between peritoneal fluid potassium and intestine ischemic grade (F = 4.77, P = 0.048)

Conclusions

Our findings show that for early detection of bowel ischemia, an evaluation of intraperitoneal potassium and pH was useful and with prolongation of ischemia, potassium changes were more significant.