Nonocclusive mesenteric ischaemia: think about it

Abdominal Emergencies in Cancer Patients

Abdominal emergencies in cancer patients encompass a wide spectrum of oncologic conditions caused directly by malignancies, paraneoplastic syndromes, reactions to the chemotherapy or often represent the first clinical manifestation of an unknown malignancy. Not rarely, clinical symptoms are the tip of an iceberg. In this scenario, the radiologist is asked to exclude the cause responsible for the patient's symptoms, to suggest the best way to manage and to rule out the underlying malignancy. In this article, we discuss some of the most common abdominal oncological emergencies that may be encountered in an emergency department.

MDCT-findings in patients with non-occlusive mesenteric ischemia (NOMI): influence of vasoconstrictor agents

OBJECTIVES

To evaluate the influence of vasoconstrictor agents (VCAs) on signs of vasoconstriction and bowel ischemia on MDCT detected in patients with non-occlusive mesenteric ischemia (NOMI).

METHODS

This 8-year single-center retrospective study consecutively included all patients with histopathologically proven NOMI who underwent MDCT ≤ 48 h prior to surgical bowel resection. Two blinded radiologists jointly reviewed each examination for signs of bowel ischemia, abdominal organ infarct, mesenteric vessel size and regularity, and ancillary vascular findings. VCA administration (length and dosage), clinical and biochemical data, risk factors, and outcomes were retrieved from patients' medical records. Subgroup comparisons were performed.

RESULTS

Ninety patients were included (59 males, mean age 65 years); 40 (44.4%) had received VCAs before MDCT. Overall mortality was 32% (n = 29), with no significant difference between the two groups. In patients treated with VCAs, the calibre of the superior mesenteric artery (SMA) was smaller (p = 0.032), and vasoconstriction of its branches tended to be more important (p = 0.096) than in patients not treated with VCAs. The presence and extent of bowel ischemia did not significantly correlate with VCA administration, but abdominal organ infarcts tended to be more frequent (p = 0.005) and involved more organs (p = 0.088). The VCA group had lower mean arterial pressure (p = 0.006) and lower hemoglobin levels (p < 0.001). Several biomarkers of organ failure and inflammation, differed significantly with VCA use, proving worse clinical condition.

CONCLUSIONS

MDCT demonstrates more severe SMA vasoconstriction and tends to show increased abdominal organ infarcts after VCA administration in NOMI patients compared to NOMI patients not treated with VCAs.

KEY POINTS

• In critically ill patients with NOMI, MDCT demonstrates VCA support via increased vasoconstriction of the main SMA and its branches. • VCA administration in NOMI patients tends to contribute to the development of organ infarcts, as shown on MDCT. • An important degree of vasoconstriction in NOMI patients may indicate insufficient resuscitation and, thus, help clinicians in further patient management.

Advances in the diagnosis of non-occlusive mesenteric ischemia and challenges in intra-abdominal sepsis patients: a narrative review

Non-occlusive mesenteric ischemia (NOMI) is a type of acute mesenteric ischemia (AMI) with a high mortality rate mainly because of a delayed or misdiagnosis. Intra-abdominal sepsis is one of the risk factors for developing NOMI, and its presence makes early diagnosis much more difficult. An increase in routine abdominal surgeries carries a corresponding risk of abdominal infection, which is a complication that should not be overlooked. It is critical that physicians are aware of the possibility for intestinal necrosis in abdominal sepsis patients due to the poor survival rate of NOMI. This review aims to summarize advances in the diagnosis of NOMI, and focuses on the diagnostic challenges of mesenteric ischemia in patients with intra-abdominal sepsis.

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.

Intestinal pneumatosis: differential diagnosis

Intestinal pneumatosis (IP) is an infrequent radiological sign defined as pathological gas infiltration into the bowel wall. It may be associated to different underlying clinical conditions-inflammatory bowel diseases, malignancies, chemotherapy, infections, immune deficiency status, trauma, intestinal ischemia, and necrosis-that are often related to emergency state and require a prompt diagnosis. All the imaging techniques, especially abdominal radiography and Computed Tomography, could detect the presence of IP and discern the forms related to emergency conditions. The differential diagnosis is essential to start an immediate clinical or surgical management and treatment. The aim of this article is to review the radiological features of IP in different illnesses, with particular attention to differential diagnosis.

Chemotherapy-induced bowel ischemia: diagnostic imaging overview

Cancer patients need multimodal therapies to treat their disease increasingly. In particular, drug treatment, as chemotherapy, immunotherapy, or various associations between them are commonly used to increase efficacy. However, the use of drugs predisposes a percentage of patients to develop toxicity in multiple organs and systems. Principle chemotherapy drugs mechanism of action is cell replication inhibition, rapidly proliferating cells especially. Immunotherapy is another tumor therapy strategy based on antitumor immunity activation trough agents as CTLA4 inhibitors (ipilimumab) or PD-1/PD-L1 inhibitors as nivolumab. If, on the one hand, all these agents inhibit tumor growth, on the other, they can cause various degrees toxicity in several organs, due to their specific mechanism of action. Particularly interesting are bowel toxicity, which can be clinically heterogeneous (pain, nausea, diarrhea, enterocolitis, pneumocolitis), up to severe consequences, such as ischemia, a rare occurrence. However, this event can occur both in vessels that supply intestine and in submucosa microvessels. We report drug-related intestinal vascular damage main characteristics, showing the radiological aspect of these alterations. Interpretation of imaging in oncologic patients has become progressively more complicated in the context of “target therapy” and thanks to the increasing number and types of therapies provided. Radiologists should know this variety of antiangiogenic treatments and immunotherapy regimens first because they can determine atypical features of tumor response and then also because of their eventual bowel toxicity.

Predictors of transmural intestinal necrosis in patients presenting with acute mesenteric ischemia on computed tomography

PURPOSE

The purpose of this study was to identify the significant imaging predictors of transmural intestinal necrosis in patients with acute mesenteric ischemia (AMI).

METHODS

The medical records and CT imaging of 48 patients between 2011 and 2019 suspected of having AMI that underwent exploratory laparotomy with bowel resection and pathological confirmation of ischemic bowel injury were retrospectively reviewed. Using histopathology as a gold standard, various parameters related to vascular insufficiency and bowel injury were analyzed and correlated with outcome of ischemic bowel necrosis using nonparametric tests. Univariate analysis was performed using Fisher's exact test followed by binary logistic regression test for multivariate analysis.

RESULTS

48 Patients (19 females, 40%) with a median age of 68.5 years (IQR of 17 years) built our retrospective cohort. 26 (54%) patients were found to have transmural intestinal necrosis on histopathology (case group) whereas 22 (46%) patients had partial mucosal injury (control group). Pneumatosis intestinalis (p = 0.005, odd's ratio of 2.07-63.14) and severity (> 70% or complete occlusion) of vascular narrowing (p = 0.019, odd's ratio of 1.39-42.30) were identified as the most significant predictors of transmural ischemic necrosis on imaging. Dilatation of bowel did not approach the statistical significance on multivariate analysis although it was found significant on univariate analysis (p = 0.041).

CONCLUSION

Pneumatosis intestinalis and severity of vascular luminal narrowing are the most important imaging predictors of transmural ischemic bowel necrosis in patients presenting with AMI. The presence of these findings on CT scan should raise high index of suspicion for irreversible transmural ischemic necrosis. In the absence of these factors, endovascular management might be beneficial.

Errors in MDCT diagnosis of acute mesenteric ischemia

The causes of diagnostic errors during daily medical practice can be several, mainly attributable to perceptual, interpretive and communication factors. The eventuality of radiological error is much more amplified in the emergency setting where a high number of complex multidetector-row computed tomography (MDCT) images must be evaluated quickly and critical time decisions need to be taken. In particular, in this context, the diagnosis of vascular intestinal diseases represents a crucial and difficult challenge in case of acute abdominal pain given the importance of being able to identify patient with high suspicious for intestinal ischemia and for a specific patient to judge if his ischemia is reversible or irreversible. Awareness of potential biases which can lead to diagnostic errors together with an extensive knowledge of the imaging features of these pathologies can lead to promptly recognize them with fewer mistakes, improving patients' outcome. This article reviews the MDCT findings of acute intestinal ischemia and acute colonic ischemia and analyzes the main types of diagnostic errors, underlining the importance of being familiarized with them to avoid misdiagnosis.

Small bowel obstruction and intestinal ischemia: emphasizing the role of MDCT in the management decision process

The objective of this article is to assess the computed tomography (CT) findings of small bowel obstruction (SBO) complicated by ischemia. SBO is a frequent clinical entity characterized by high morbidity and mortality. The radiologic aim is not just to diagnose the obstruction itself but to rule out the presence of complications related to SBO. This is crucial for differentiating which patients can be safely treated non-operatively from the ones who may need an urgent surgical approach. The main complication of SBO is intestinal ischemia. In the emergency setting, CT imaging is the modality of choice for SBO because of its ability to assess the bowel wall, the supporting mesentery and peritoneal cavity all in one. On the other hand, the radiologist who documents an intestinal ischemia should think about SBO as possible cause. In this case, the main finding which helps the radiologist in the identification of SBO is the presence of multiple and packed valvulae conniventes in the dilated bowel wall and the "transition zone" that indicates the passage between compressed and decompressed small bowel, otherwise the localization of the obstruction cause. Once the site of obstruction has been recognized, the other issue is to assess the cause of obstruction, considering that the most common cause of SBO remains "unidentified" and related to intra-abdominal adhesions. After that, the following most important point is to rule out the presence of an ischemic bowel and mesenteric changes associated to SBO. CT signs of bowel ischemia include reduced or increased bowel wall enhancement, mesenteric edema or engorgement, fluid or free air in the peritoneal cavity. This condition usually leads to an urgent laparotomy and, in some cases, to a surgical resection.

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.

Non-occlusive mesenteric ischemia (NOMI) and prognostic signs at CT: reperfusion or not reperfusion that is the question!

PURPOSE

Non-occlusive mesenteric ischemia (NOMI) is a misdiagnosed and dangerous condition. To our knowledge, a comprehensive evaluation of CT parameters that can predict the outcome of patients suffering from NOMI is still missing.

MATERIALS AND METHODS

Contrast-enhanced CT examination of 84 patients with a confirmed diagnosis of NOMI (37 with clinical and laboratory confirmation and 47 biopsy or surgery proven) was retrospectively reviewed by assessing vessels, mesentery, bowel, and peritoneal cavity CT quantitative and dichotomous parameters, and data were analyzed with Fisher's test. Diameter of superior mesenteric artery (SMA), celiac trunk (CT), inferior vena cava (IVC), superior mesenteric vein (SMV), and differences in CT HU (Delta HU) of the bowel wall before and after intravenous contrast media (ICM) administration were correlated to the patients' outcome using ANOVA test. Receiver operating characteristic (ROC) curves were elaborated after a binary logistic regression was performed.

RESULTS

Increased number and diameter of vessels, bowel wall thickening, and hypervascularity were more frequent in patients with good prognosis. Conversely, pale mesentery, paper thin, hypovascularity, and aeroportia were more frequent in patients with bad prognosis. A significant correlation between diameters of SMA, CT, IVC, IMA, and SMV and outcome was found at univariate analysis. Also Delta HU resulted to be correlated with the outcome. At multivariate analysis only IVC and Delta HU were significant (p = 0.038 and 0.01) and the combined AUC resulted in 0.806 (CI 0.708-0.903).

CONCLUSION

Dichotomous signs of reperfusion and quantitative CT parameters can predict the outcome of patients with NOMI. In particular the combination of IVC diameter and Delta HU of bowel wall allows to predict the prognosis with the highest accuracy.

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.

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.

Diagnostic performance of CT for the detection of transmural bowel necrosis in non-occlusive mesenteric ischemia

OBJECTIVES

To evaluate the diagnostic performance of CT for transmural necrosis (TN) in non-occlusive mesenteric ischemia (NOMI) according to the bowel segment involved.

METHODS

From January 2009 to December 2019, all patients admitted to the intensive care unit (ICU) and requiring laparotomy for NOMI were retrospectively studied. CT had to have been performed within 24 h prior to laparotomy and were reviewed by two abdominal radiologists, with a consensus reading in case of disagreement. A set of CT features of mesenteric ischemia were assessed, separating the stomach, jejunum, ileum, and right (RC) and left colon (LC). Univariate and multivariate analyses were performed to identify features associated with TN. Its influence on overall survival (OS) was assessed.

RESULTS

Among 145 patients, 95 (66%) had ≥ 1 bowel segment with TN, including 7 (5%), 31 (21%), 43 (29%), 45 (31%), and 52 (35%) in the stomach, jejunum, ileum, RC, and LC, respectively. Overall inter-reader agreement of CT features was significantly lower in the colon than in the small bowel (0.59 [0.52-0.65] vs 0.74 [0.70-0.77] respectively). The absence of bowel wall enhancement was the only CT feature associated with TN by multivariate analysis, whatever the bowel segment involved. Proximal TN was associated with poorer OS (p < 0.001).

CONCLUSIONS

The absence of bowel wall enhancement remains the most consistent CT feature of transmural necrosis, whatever the bowel segment involved in NOMI. Inter-reader agreement of CT features is lower in the colon than in the small bowel. Proximal TN seems to be associated with poorer OS.

KEY POINTS

• The absence of bowel wall enhancement is the most consistent CT feature associated with transmural necrosis in NOMI, whatever is the bowel segment involved. • Inter-reader agreement is lower in the colon than in the small bowel in NOMI. • In NOMI, the more proximal the bowel necrosis, the worse the prognosis.

Bowel wall thickening on computed tomography scan: Inter-observer agreement and correlation with endoscopic findings

BACKGROUND AND STUDY AIMS

Bowel wall thickening (BWT) on computed tomography (CT) has been frequently reported by radiologists. There are no clear guidelines regarding the level of thickening that is correlated with definite pathology. Radiologists usually rely on their overall subjective impression, and studies on inter-observer agreement (IOA) are lacking. This study evaluated IOA concerning BWT found on abdominal CT and identified the corresponding findings on endoscopy.

PATIENTS AND METHODS

Reports of abdominal CTs performed between January 2000 and December 2015 containing the term 'thickening' were retrieved from the radiology department database. Corresponding patients who later underwent endoscopy were included. IOA concerning BWT was evaluated using a randomly mixed sample of 80 patients with normal findings or pathological BWT on endoscopy. A search for predictive factors for the subsequent finding of malignancy on endoscopy was performed using multivariate analysis.

RESULTS

During the study period, 6142 CT scans described thickening, equivalent to a BWT prevalence of 13.7%. Ninety-one patients (mean age, 58 years) were included in the analysis. Thickening was found most commonly in the stomach (38.5%), followed by the rectum (22%) and small intestine (14%). Twenty-seven patients (29.7%) exhibited diffuse BWT, whereas 64 patients showed localised BWT (70.3%). Biopsy was performed for 64 of 91 patients with endoscopies. Among these patients, 8.8% exhibited normal findings, whereas inflammation and malignancy were discovered in 25 and 51.6% of patients, respectively, with a positive predictive value for malignancy of 0.36. The IOA concerning CT for predicting significantly pathological BWT was moderate (mean κ = 0.6). A strong association was evident between the presence of lymph nodes on CT and the presence of neoplastic lesions.

CONCLUSION

Our study strongly recommends endoscopic follow-up of patients exhibiting BWT irrespective of the thickening location, especially if it is associated with lymphadenopathy. IOA between radiologists was moderate.

Successful surgical treatment for nonocclusive mesenteric ischemia of a wide area of the intestine accompanied by gastric conduit necrosis after esophagectomy for esophageal cancer: a case report and review of the literature

BACKGROUND

Nonocclusive mesenteric ischemia (NOMI) has been reported to be a life-threating disease. Gastric conduit necrosis is known as a critical postoperative complication after esophagectomy for esophageal cancer. We encountered a rare case of NOMI of a wide area of the intestine accompanied by gastric conduit necrosis after esophagectomy, which was successfully treated with an emergency operation.

CASE PRESENTATION

A 67-year-old man presented with dysphagia. He was diagnosed with middle thoracic advanced esophageal cancer. After neoadjuvant chemotherapy, he underwent subtotal esophagectomy with lymphadenectomy and gastric conduit reconstruction. On postoperative day (POD) 2, he had diarrhea, high fever, and low blood pressure, which were treated with catecholamines. Laboratory data revealed acidosis and severe sepsis with multi-organ failure, including the kidneys. Although enhanced computed tomography did not exhibit definite findings of bowel ischemia, upper gastrointestinal endoscopy revealed necrotic mucosal changes in the whole gastric conduit. Therefore, we made a diagnosis of septic shock caused by gastric conduit necrosis and performed an emergency operation. When we explored the abdominal cavity, we found not only gastric conduit necrosis but also intermittent necrotic changes in the intestinal wall from the jejunum to the rectum. Therefore, NOMI was diagnosed. We performed an excision of the gastric conduit and 2 m of the small intestine, as well as total colectomy. After the second operation, prostaglandin E1 was administered intravenously as the treatment for NOMI, and sepsis was improved. On POD 122, he was self-discharged. He died of recurrence of lung metastasis from the esophageal cancer 9 months after the first operation.

CONCLUSION

When a patient has a critical status, including severe sepsis or severe acidosis, after esophagectomy, we should consider the possibility of NOMI in addition to gastric conduit necrosis and aim to diagnose and treat it immediately with an urgent operation.

Comparison of diagnostic accuracy for nonocclusive mesenteric ischemia in models with biomarkers including intestinal fatty acid-binding protein in addition to clinical findings

BACKGROUND

Nonocclusive mesenteric ischemia (NOMI) is an acute and life-threatening gastrointestinal disorder, requiring rapid therapeutic intervention for ischemic bowel. However, its rapid detection remains challenging. This retrospective, observational study was aimed at comparing the diagnostic accuracy for NOMI in models of biomarkers, including intestinal fatty acid-binding protein (I-FABP), and clinical findings.

METHODS

All consecutive patients who presented to the emergency department of the study hospital with suspected NOMI were prospectively enrolled. Receiver operating characteristic analysis compared the diagnostic accuracy of I-FABP with traditional biomarkers (white blood cell count, C-reactive protein, lactate, creatine kinase, and D-dimer) alone and in combination with the baseline model established from clinical findings.

RESULTS

Of 96 patients with suspected NOMI, 25 (26.0%) were clinically diagnosed with NOMI. In-hospital mortality was higher in patients with NOMI than those with other conditions (56.0% vs. 4.2%, p < 0.001). Receiver operating characteristic analyses revealed that the I-FABP model had the highest area under the curve (0.805) in the diagnosis of NOMI, compared with other biomarkers. The diagnostic model of clinical findings including age, cardiovascular disease history, undergoing hemodialysis, hypotension, and consciousness disturbance in combination with I-FABP showed the best discrimination (area under the curve, 0.883), compared with other biomarkers. The bootstrap optimism estimate showed the lowest discrimination among the other models with other biomarkers (0.006).

CONCLUSION

The usefulness of I-FABP for final diagnosis of NOMI in patients with clinically suspected NOMI at the emergency department was internally validated. Further external validation study is warranted.

LEVEL OF EVIDENCE

Diagnostic test, level III.

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.

Non-occlusive Mesenteric Ischemia as a Fatal Complication in Acute Pancreatitis: A Brief Radiological Comment

Non-occlusive mesenteric ischemia (NOMI) is the result of the reduction of mesenteric blood supply, due to mesenteric arterial vasoconstriction secondary to hypotension in cases of shock, septicemia, dehydration, heart surgery, or major abdominal surgery. NOMI represents a complex and often misdiagnosed syndrome. Imaging, and in particular CT, has a remarkable importance in NOMI, and despite its complexity, it could allow an early diagnosis and an improved management resulting in life-threatening therapeutic approaches, much better than in the past, provided it is correctly performed and interpreted by experienced radiologists.

Non-occlusive Mesenteric Ischemia as a Fatal Complication in Acute Pancreatitis: A Case Series

BACKGROUND

Vascular complications of severe acute pancreatitis are well known and largely described unlike non-occlusive mesenteric ischemia, which is a rare and potentially fatal complication. Non-occlusive mesenteric ischemia is an acute mesenteric ischemia without thrombotic occlusion of blood vessels, poorly described as a complication of acute pancreatitis.

METHODS

We retrospectively reviewed a prospectively maintained registry of all pancreatic diseases referred to our center from 2013 to 2018, in order to determine the causes of early death. We identified three patients who died within 48 h after hospital admission from severe acute pancreatitis complicated by irreversible non-occlusive mesenteric ischemia. Their clinical presentation, management, and outcomes were herein reported.

RESULTS

Three consecutive patients with severe acute pancreatitis developed non-occlusive mesenteric ischemia within the first 5 days after onset of symptoms and died 48 h after non-occlusive mesenteric ischemia diagnosis despite optimal intensive care management and surgery, giving a prevalence of 3/609 (0.5%). Symptoms were unspecific with consequently potential delayed diagnosis and management. High doses of norepinephrine required for hemodynamic support (n = 3) potentially leading to splanchnic vessels vasoconstriction, transient hypotension (n = 3), and previous severe ischemic cardiomyopathy (n = 1) could be involved as precipitating factors of non-occlusive mesenteric ischemia.

CONCLUSION

Non-occlusive mesenteric ischemia can be a fatal complication of acute pancreatitis but is also challenging to diagnose. Priority is to reestablish a splanchno-mesenteric perfusion flow. Surgery should be offered in case of treatment failure or deterioration but is still under debate in early stage, to interrupt the vicious circle of intestinal hypoperfusion and ischemia.

Non-occlusive mesenteric ischemia: two case reports and a short review of the literature

INTRODUCTION

Non-occlusive mesenteric ischemia (NOMI) is an infrequent cause of acute mesenteric ischemia with atypical symptoms and a high mortality.

PATIENTS AND METHODS

We report two cases of NOMI characterized by their difference in etiology, treatment and outcome.

RESULTS

In the first case, the patient developed NOMI after septic shock, she was successfully treated with surgery. The second patient experienced two episodes of cardiac arrest followed by NOMI. He received only supportive care and died shortly after. We present a short review of the literature, discussing epidemiology, pathophysiology, clinical presentations, diagnosis and management of NOMI.

CONCLUSION

NOMI is a rare disease with a difficult diagnosis. Early recognition and treatment with supportive therapy, vasodilator drugs and possibly surgery can significantly lower mortality.

Acute mesenteric ischemia: guidelines of the World Society of Emergency Surgery: a brief radiological commentary

The aim of this letter is to report some deeper explanations regarding the role of imaging in acute mesenteric ischemia.

The correlation between some computed tomography findings and the cause of ischemia as well as other main factors that could condition the computed tomography appearance of this critical issue is also discussed.

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.

Successful treatment of non-occlusive mesenteric ischemia with indocyanine green fluorescence and open-abdomen management

Non-occlusive mesenteric ischemia (NOMI), which can lead to multifocal and segmental intestinal necrosis without demonstrable occlusion in the main mesenteric artery, is associated with extremely high mortality. Because these intestinal ischemic changes can progress, it is difficult to make a definitive determination intraoperatively as to whether resection of damaged intestine is required. A 62-year-old man who underwent esophagectomy for advanced cervicothoracic esophageal cancer complained of severe abdominal pain on postoperative day 4. Enhanced computed tomography revealed pneumatosis intestinalis in the wall of the small bowel. Emergency laparotomy revealed ischemia in segments of the small intestine suspicious for NOMI. Intraoperative evaluation of the mesenteric and bowel circulation was performed under indocyanine green (ICG) fluorescence. Although the ischemic bowel segments were visible, open-abdomen management was undertaken so that mesenteric and bowel circulation could be reexamined 24 h later. During the second-look operation, the small intestine was able to be preserved because intestinal perfusion was confirmed on revisualization under ICG fluorescence. The present case demonstrated that open-abdomen management and repeat visualization under ICG fluorescence are effective in preserving damaged intestine during surgery for NOMI.

Effect of Remote Ischemic Preconditioning on Intestinal Ischemia-Reperfusion Injury in Adults Undergoing On-Pump CABG Surgery: A Randomized Controlled Pilot Trial

OBJECTIVE

Cardiopulmonary bypass (CPB) surgery commonly threatens the heart and remote organs with ischemia-reperfusion injury. Transient episodes of ischemia to nonvital tissue, known as remote ischemic preconditioning (RIPC), is thought to help local and remote vital organs to withstand subsequent ischemic insults.

DESIGN

Prospective, randomized, double-blinded control trial.

SETTING

Tertiary referral academic teaching hospital.

PARTICIPANTS

Thirty patients undergoing elective CPB surgery INTERVENTION: RIPC was achieved via three 5-minute cycles of upper limb ischemia using a blood pressure cuff or control (sham cuff).

MEASUREMENTS AND MAIN RESULTS

Primary outcome was the occurrence of intestinal injury, as measured by an increase in intestinal fatty acid binding protein (I-FABP). Secondary outcomes included incidence of gastrointestinal complications and duration of intensive care unit (ICU) stay. RIPC did not affect serum IFABP levels at the end of surgery and on the first postoperative day (p = 0.697 and p = 0.461, respectively). For all patients, mean I-FABP levels significantly increased at the end of surgery and decreased to under baseline levels on the first postoperative day (from a mean [± standard deviation] baseline value of 764 ± 492 pg/mL to 2,002 ± 974 pg/mL and decreased to 568 ± 319 pg/mL, p < 0.001). All patients remained clinically absent of gastrointestinal complications until hospital discharge. Duration of ICU stay was not correlated with I-FABP levels at the end of surgery. Neither duration of CPB nor duration of aortic clamping significantly correlated with postoperative I-FABP levels.

CONCLUSIONS

These findings suggest that RIPC does not affect intestinal injury in patients undergoing CPB surgery. In patients undergoing cardiac surgery, intestinal injury appears to be moderate and transient without any clinical relevant complication.

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.

Acute mesenteric ischemia (Part II) - Vascular and endovascular surgical approaches

The modern treatment of acute mesenteric ischemia (AMI) requires seamless collaboration of gastrointestinal surgeons, vascular surgeons, and interventional radiologists. The treatment strategy is straightforward aiming at rapid restoration of blood flow to the intestine. Bowel resection is performed on demand. The first thing to consider is the patient's clinical condition at presentation, whether there are signs of peritonitis or not, and whether the patient is hemodynamically stable or not. Second, there are four etiologies of AMI that need to be distinguished as they differ in treatment: superior mesenteric artery embolism, mesenteric arterial occlusive disease, mesenteric venous thrombosis, and non-occlusive mesenteric ischemia. In this review, we describe the basic vascular and endovascular treatment modalities accompanied by a simple algorithm for the various situations in AMI. Furthermore, the indications for damage control and primary definitive surgery are discussed.

MDCT in ischaemic colitis: how to define the aetiology and acute, subacute and chronic phase of damage in the emergency setting

Ischemic colitis (IC) is the most common vascular disorder of the gastrointestinal tract with a reported incidence of 6.1-44 cases/100,000 person years with confirmatory histopathology. However, the true incidence of IC poses some difficulty, and even vigilant clinicians with patients at high risk often miss the diagnosis, since clinical presentation is non-specific or could have a mild transient nature. Detection of IC results is crucial to plan the correct therapeutic approach and reduce the reported mortality rate (4-12%). Diagnosis of IC is based on a combination of clinical suspicion, radiological, endoscopic and histological findings. Some consider colonoscopy as a diagnostic test of choice; however, preparation is required and it is not without risk, above all in patients who are severely ill. There are two manifestations of vascular colonic insult: ischaemic and reperfusive. The first one occurs above all during ischaemic/non-occlusive mesenteric ischaemia; in this case, the colonic wall appears thinned with dilated lumen and fluid appears in the paracolic space. When reperfusion occurs, the large bowel wall appears thickened and stratified, because of subepithelial oedema and/or haemorrhage, with consequent lumen calibre reduction. Shaggy contour of the involved intestine and misty mesentery are associated with the pericolic fluid. The pericolic fluid results are a crucial finding for IC diagnosis since its evidence suggests the presence of an ongoing damage thus focusing the attention on other pathological aspects which could be otherwise misdiagnosed, such as thinned or thickened colonic wall. Moreover, the pericolic fluid may increase or decrease, depending on the evolution of the ischaemic damage, suggesting the decision of medical or surgical treatment. Radiologists should not forget the hypothesis of IC, being aware that multidetector CT could be sufficient to suggest the diagnosis of IC, allowing for early identification and grading definition, and in a short-term follow-up, discriminating patients who need urgent surgery from patients in whom medical treatment and follow-up can be proposed.

Reperfusion in non-occlusive mesenteric ischaemia (NOMI): effectiveness of CT in an emergency setting

OBJECTIVE

To investigate the CT features of reperfusion (presence/absence) in non-occlusive mesenteric ischaemia (NOMI) and their prognostic value in an emergency setting.

METHODS

A revision was undertaken of imaging from 20 patients (16 males/4 females) with a dismissal summary of NOMI. All patients had previously undergone a minimum of one multidetector CT examination, and consequently underwent surgery (n = 8), autopsy (n = 2), angiography (n = 1) or endoscopy (n = 9). An evaluation of the CT scans was conducted to determine vessels, mesentery, bowel and peritoneal cavity features. The superior mesenteric artery (SMA) average diameter of NOMI cases were compared with 30 controlled cases. Kappa, Kolmogorov-Smirnov (K-S) and Fisher's exact tests were used for statistical analysis.

RESULTS

A mean SMA diameter significantly smaller than that of the controlled cases was found for patients with NOMI (K-S test: D = 0.75, p = 3.7 × 10-08). Fisher's exact tests showed a strong connection between the presence of reperfusion and mesenteric fat stranding (p = 0.026), bowel wall thickening (p = 3.2 × 10-05) and a high attenuation of the bowel wall on unenhanced CT images (p = 2.8 × 10-04). A reduction in mortality was significantly linked to the combination of normal mesenteric vessels and wall thickening (p = 0.034).

CONCLUSION

Analysis of not only vessels findings but also mesentery and bowel CT features will support the identification of NOMI with or without a reperfusion event in an emergency setting. A strong correlation between some CT features and lower mortality exists.

ADVANCES IN KNOWLEDGE

CT features of NOMI with or without reperfusion are demonstrated. Correctly assessing the presence of reperfusion in NOMI, may allow better management of these conditions in the emergency setting.

Multidetector CT in emergency radiology: acute and generalized non-traumatic abdominal pain

Multidetector CT (MDCT) is an imaging technique that provides otherwise unobtainable information in the diagnostic work-up of patients presenting with acute abdominal pain. A correct working diagnosis depends essentially on understanding the individual patient's clinical data and laboratory findings. In haemodynamically stable patients with acute severe and generalized abdominal pain, MDCT is now the preferred imaging test and gives invaluable diagnostic information, also in unstable patients after stabilization. In this descriptive review, we focus our attention on acute, severe and generalized or undifferentiated non-traumatic abdominal pain. The main differential diagnoses are acute pancreatitis, gastrointestinal perforation, ruptured abdominal aneurysm and acute mesenteric ischaemia. We will provide radiologist readers with a technical guide to optimize MDCT imaging protocols and list the major CT signs essential to reach a correct diagnosis and guide the best treatment.

Small Bowel Perforations: What the Radiologist Needs to Know

The incidence of small bowel perforation is low but can develop from a variety of causes including Crohn disease, ischemic or bacterial enteritis, diverticulitis, bowel obstruction, volvulus, intussusception, trauma, and ingested foreign bodies. In contrast to gastroduodenal perforation, the amount of extraluminal air in small bowel perforation is small or absent in most cases. This article will illustrate the main aspects of small bowel perforation, focusing on anatomical reasons of radiological findings and in the evaluation of the site of perforation using plain film, ultrasound, and multidetector computed tomography equipments. In particular, the authors highlight the anatomic key notes and the different direct and indirect imaging signs of small bowel perforation.

Errors in multidetector row computed tomography

Multidetector row computed tomography (MDCT) represents the technique of choice for the majority of pathologies today and is responsible for the majority of diagnoses. However, despite the low number of studies dedicated to errors in MDCT, CT reporting seems especially prone to generating errors and errors are an inevitable part of MDCT practice. Most of these arise during image interpretation but, differently from other radiological techniques, the awareness of radiologists regarding technical CT aspects and pathologies substantially contribute in generating errors, in particular because CT technology expands rapidly and radiologists do not routinely receive specific and appropriate training for its use and because CT examinations are not the same for each patient and each pathology and the choice of the most appropriate CT examination (including the dose exposure to the patient) presumes a very large awareness from radiologists. This review is aimed at increasing awareness regarding the type of errors in MDCT and in particular to also highlight technical and procedural errors.