Mesenteric ischemia: what the radiologist needs to know

Peritoneal dialysis-associated peritonitis, caused by superior mesenteric artery thrombosis with intestinal necrosis: a case report

Peritoneal dialysis (PD)-associated peritonitis is a common complication of PD. Enteric peritonitis is defined as peritonitis arising from an intestinal or intra-abdominal organ source. The delay in the diagnosis or treatment of enteric peritonitis has been reported to increase mortality. Therefore, the early consideration of enteric peritonitis, particularly in cases of culture-negative peritonitis, is imperative. A 67-year-old Japanese man who had been undergoing PD for 3 years, was admitted to our hospital with a diagnosis of PD-associated peritonitis. A month previously, he experienced a bleeding gastric ulcer, which led to severe anemia (hemoglobin 6.3 mg/dL), followed by thrombocytosis. On admission, peritoneal fluid analysis showed a high white blood cell count (WBC: 8,570 /µL), with neutrophils predominating (74.5%). Cultures of both his dialysis effluent and blood were negative. After admission, the WBC count of the dialysis effluent gradually decreased alongside antibiotic therapy, but the patient's abdominal pain did not improve. After 4 days, enhanced computed tomography showed superior mesenteric artery (SMA) thrombosis and intestinal necrosis. Therefore, emergency intestinal resection and PD catheter removal were performed, and then antithrombosis therapy was initiated. Because the patient's abdominal pain was improved and platelet count and D-dimer concentration were reduced by these treatments, he was discharged from the hospital after 47 days. Thus, we report a rare case of culture-negative PD-associated peritonitis, which was caused by SMA thrombosis and intestinal necrosis. It is likely that combination of severe calcification of SMA and prolonged thrombocytosis secondary to the severe anemia contributed to the thrombosis.

CT evaluation of bowel wall enhancement in pneumatosis intestinalis: preventing non-therapeutic laparotomies

PURPOSE

To evaluate the diagnostic performance of bowel wall enhancement for diagnosing concomitant bowel ischemia in patients with parietal pneumatosis (PI) diagnosed at abdominal CT.

MATERIALS AND METHODS

From January 1, 2012 to December 31, 2021, 226 consecutive patients who presented with PI on abdominal CT from any bowel segment were included. Variables at the time of the CT were retrospectively extracted from medical charts. CT examinations were blindly analyzed by two independent radiologists. The third reader classified all disagreement of bowel enhancement in three categories: (1) normal bowel enhancement; (2) doubtful bowel wall enhancement; (3) absent bowel wall enhancement. Multivariable logistic regression analysis was performed. Concomitant bowel ischemia was defined as requirement of bowel resection specifically due to ischemic lesion in operated patients and death from bowel ischemia in non-operated patients.

RESULTS

Overall, 78/226 (35%) patients had PI associated with concomitant bowel ischemia. At multivariate analysis, Only absence or doubtful bowel wall enhancement was associated with concomitant bowel ischemia (OR = 167.73 95%CI [23.39-4349.81], P < 0,001) and acute mesenteric ischemia associated with PP (OR = 67.94; 95%CI [5.18-3262.36], P < 0.009). Among the 82 patients who underwent a laparotomy for suspected bowel ischemia, rate of non-therapeutic laparotomy increased from 15/59 (25%), 2/6 (50%) and 16/17 (94%) when bowel wall enhancement was absent, doubtful and normal respectively.

CONCLUSION

Absence of enhancement of the bowel wall is the primary feature associated with concomitant bowel ischemia. It should be carefully assessed when PI is detected to avoid non-therapeutic laparotomy.

Acute mesenteric ischaemia: a rare complication mimicking necrotising enterocolitis in a premature infant

Acute mesenteric ischaemia (AMI) is a life-threatening gastrointestinal complication uncommonly described in premature infants. The diagnosis of AMI is challenging and may be delayed due to the limitation of accurate diagnostic imaging and non-specific clinical signs. Furthermore, AMI can be misdiagnosed as necrotising enterocolitis (NEC) due to the overlapping clinical and radiological features. Though known to be associated with high mortality rates, early recognition and intervention can improve the survival rates in infants with AMI. We describe a case of a premature infant who presented with an acute abdomen and haemodynamic collapse, initially treated for NEC but later diagnosed with AMI intraoperatively. Due to the extensive bowel necrosis, surgical intervention was rendered futile and the infant finally succumbed to the disease.

Ultrasound evaluation of portal venous gas and its mimics

Portal venous gas on abdominal ultrasound classically represents an indirect indicator of bowel ischemia, a critical condition which poses a high patient mortality and therefore warrants emergent corrective action. While the classic appearance of portal venous gas on ultrasound is well-described in the literature, the characteristic descriptors are nonspecific and may actually represent other less emergent mimics. Therefore, while radiologists should remain vigilant for the detection of findings corresponding to portal venous gas, they should also be aware of similar-appearing entities in order to provide the most accurate diagnosis. This pictorial essay will open with imaging examples of true portal venous gas attributable to bowel ischemia and describe the classic features which should alert radiologists to this specific diagnosis. Subsequently, this pictorial essay will provide imaging examples of other various other clinical entities which on ultrasound may share similar imaging characteristics. An important objective of this pictorial essay is to highlight distinguishing imaging features along with specific clinical circumstances for each pathological entity which can direct radiologists into identifying the correct diagnosis.

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.

[Emergency diagnoses in the gastrointestinal tract]

Gastrointestinal emergencies are a frequent reason for presentation in the emergency department and involve patients of all ages. The patients must undergo an immediate cross-sectional imaging as in many cases the underlying pathology is a life-threatening condition, which often needs surgical or in some cases also interventional radiological treatment. In this overview, the most important differential diagnoses and their characteristics on cross-sectional imaging are presented.

Revascularization Strategies for Acute and Chronic Mesenteric Ischemia: A Narrative Review

Mesenteric ischemia is a challenging condition characterized by insufficient blood perfusion to the mesentery and, consequently, intestinal tissues that continues to perplex clinicians. Despite its low prevalence, the condition's variable clinical presentation and elusive radiographic diagnosis can delay life-saving interventions in the acute setting and deteriorate the quality of life of patients when left undiagnosed or misdiagnosed.

PURPOSE

Review and summarize recent diagnostic updates and emergent intervention strategies for acute and chronic mesenteric ischemia.

METHODS

A narrative review of all relevant studies from January 2022 through September 2023.

RESULTS

A total of 11 studies from MEDLINE, supplemented with 44 studies from Google Scholar, were included in the review.

CONCLUSIONS

Both acute and chronic mesenteric ischemia propose diagnostic and therapeutic challenges for interventionalists. Computed tomographic angiography remains the diagnostic modality of choice for both. Open surgical intervention remains the gold standard for acute mesenteric ischemia, while endovascular techniques are preferred for chronic mesenteric ischemia.

The geriatric index of comorbidity as an outcome predictor of patients with acute mesenteric ischemia due to superior mesentery artery thromboembolism

OBJECTIVE

To describe the impact of comorbidities on in-hospital mortality and overall survival in patients with acute mesenteric ischemia (AMI) due to superior mesentery artery (SMA) thromboembolism.

METHODS

A retrospective study was conducted for 40 patients with AMI due to SMA thromboembolism who were treated in our hospital between February 2013 and December 2019. The presence of comorbidities was described and their severities were classified into 1-4 levels by Geriatric Index of Comorbidity (GIC), the comorbidities were defined as any distinct additional clinical entity that has existed. Univariate and cox proportional-hazards analyses were performed to determine the effect of comorbidities on in-hospital mortality and overall survival.

RESULTS

During a mean follow-up of 15.05 ± 18.02 months (range from 0.3 to 58 months) for the 40 patients with AMI due to SMA thromboembolism, In-hospital mortality rate was 52.5% (21/40). One-year, 2-year, and 3-year overall estimated survival rates by the Kaplan-Meier method were 45%, 34%, and 26.5%, respectively, the average overall survival time was 20.84 ± 3.95 (95% CI: 13.10-28.58) months. In-hospital mortality was significantly related to the GIC classification (χ2 = 7.86, p = 0.049). The average overall survival was significantly related to the malignant tumor in pre-existing comorbidities and GIC classification (log-rank, p = 0.001). Cox proportional-hazards regressions analysis showed that the class 4 of comorbidities was an independent prognostic factor of mortality (p = 0.031, HR = 10.45 [95% CI: 1.24-87.70]).

CONCLUSION

Comorbidity is common and an important factor associated with all-cause mortality in AMI patients due to SMA thromboembolism. In managing AMI patients, we recommend a timely diagnosis of both AMI condition and its associated comorbidities.

Acute Pelvic Pain: Role of Imaging in the Diagnosis and Management

Acute pelvic pain is defined as a new symptom that has been present for less than 3 months. It is a common symptom seen in 15%-24% of women and is the indication for 20% of laparoscopies and 2%-10% of outpatient gynecologic visits. The pregnancy status and correlation of the physical symptoms with clinical findings are important. Ultrasound is the imaging modality of choice, not only to diagnose gynecological causes, but also bowel or urinary tract related causes of pelvic pain. When an ultrasound scan is inconclusive, a computed tomography scan is the preferred means of additional imaging and is particularly useful in gastrointestinal and urogenital causes of pelvic pain. Gynecological causes of acute pelvic pain include uterine, tubal, or ovarian pathology; non-gynecological causes include bowel diseases, such as appendicitis and diverticulitis; urogenital causes such as ureteral, bladder stones, and urinary tract infection as well as vascular causes. Ultrasound imaging alone may provide a definitive diagnosis in underlying conditions that require prompt medical or surgical intervention in gynecological conditions, such as ovarian torsion, ectopic pregnancy, and non-gynecological condition, such as in acute appendicitis.

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

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

Superior mesenteric artery thrombosis with concomitant pancreaticoduodenal artery pseudoaneurysm in a 60-year-old male patient - A case report

INTRODUCTION

Vascular complications like superior mesenteric artery (SMA) thrombosis and pancreaticoduodenal artery (PDA) pseudoaneurysm carry high morbidity and mortality. SMA provides the primary arterial supply to the small intestine and ascending colon. PDA aneurysms are extremely rare, accounting for only 2 % of all visceral artery aneurysms. We present a rare case of SMA thrombosis with concomitant PDA pseudoaneurysm.

CASE PRESENTATION

Herein is the case of a 60-year-old male who presented with rectorrhagia, persistent generalized abdominal pain. After being diagnosed with colitis and mesenteric artery thrombosis based on a computed tomography (CT) scan, he was discharged from the hospital with rivaroxaban and mesalazin. However, he had to return to the hospital due to worsening of the symptoms. After a proper workout, SMA artery thrombosis with a concomitant PDA pseudoaneurysm was diagnosed for him. Therefore, he underwent surgery to stent the thrombosis and coil the pseudoaneurysm. His symptoms dramatically improved after the treatment.

DISCUSSION

Angiography is the diagnostic and, with embolization, therapeutic procedure of choice, with surgery as a backup if embolization fails. However, even with these procedures, the mortality rate is high if the pseudoaneurysm ruptures.

CONCLUSION

In order to carry out the proper choice of surgical treatment before further complications occur, SMA thrombosis and PDA pseudoaneurysms must be investigated in each patient presenting with nonspecific abdominal pain, regardless of the risk factors.

Acute management of mesenteric emergencies: Tailoring the solution to the problem

Acute mesenteric ischemia (AMI) constitutes a life-threatening problem that can result in death, multiorgan failure, and severe nutritional disability. Although AMI is a rare cause of acute abdominal emergencies, ranging between 1 and 2 individuals per 10,000, the morbidity and mortality rates are high. Arterial embolic etiology composes nearly one-half of AMIs, with a sudden onset of severe abdominal pain considered the most common symptom. Arterial thrombosis is the second most common cause of AMI, which presents similarly to arterial embolic AMI, although often more severe due to anatomic differences. Veno-occlusive causes of AMI are the third most common and are associated with an insidious onset of vague abdominal pain. Each patient is unique, and the treatment plan should be tailored to their individual needs. This may include considering the patient's age, comorbidities, and overall health, as well as their preferences and personal circumstances. A multidisciplinary approach involving specialists from different fields, such as surgeons, interventional radiologists, and intensivists, is recommended for the best possible outcome. Potential challenges in tailoring an optimal treatment plan for AMI may include delayed diagnosis, limited availability of specialized care, or patient factors that make some interventions less feasible. Addressing these challenges requires a proactive and collaborative approach, with regular review and adjustment of the treatment plan as needed to ensure the best possible outcome for each patient.

Acute mesenteric ischemia and COVID-19: an integrative review of the literature

The novel coronavirus disease 2019 (COVID-19) has spread rapidly around the world after the first cases were reported in December 2019 in China. Despite the prevention of the symptoms presented, extrapulmonary manifestations were identified. In particular, there was an increase in cases of Acute Mesenteric Ischemia (AMI), raising its incidence to 1.9%-3.8% in infected patients. The aim of this study was to investigate the existence of an association between IMA and COVID-19 through the literature. An Integrative Literature Review was carried out. The research question was "mesenteric ischemia in patients with COVID-19: coincidence or association?". After searching the database and applying the inclusion and exclusion criteria, 44 were selected for analysis. COVID-19 was confirmed by RT-PCR and imaging tests, gastrointestinal manifestations, alterations and primarily tomographic imaging findings were identified. Most patients were accelerated to laparotomy. As explanations include direct endothelial and injury by the binding of the ACE-2 virus, between hyperinflammation and hypercoagulability, dysregulation of the renin-angiotensin-aldosterone system and factors associated with the severity of the virus. IMA is an emergency with high associated morbidity and mortality, these cases may be a consequence mainly of the thromboinflammatory mechanism associated with SARS-CoV-2. An early diagnosis, diagnosis and diagnoses are crucial to clinical treatment; an assessment regime should be considered in accordance with current evidence and guidelines.

Acute Mesenteric Ischemia in COVID-19 While Receiving Prophylactic Enoxaparin

COVID-19 infection is known to cause thromboembolic complications. This is why patients hospitalized with COVID-19 are put on prophylactic anticoagulation. We present the case of a Caucasian woman, aged 71 years, with risk factors of class 1 obesity, hyperlipidemia, and hypertension, initially admitted for COVID-19 pneumonia, and later developed acute mesenteric ischemia followed by pulmonary embolism. These incidents occurred while the patient was receiving high-dose prophylactic enoxaparin (40 mg twice daily). COVID-19 associated acute mesenteric ischemia is a complication with high mortality. Therefore, high suspicion, early recognition, and surgical management is necessary. Apart from that, this case emphasizes the question of whether there is a need for proactively administering therapeutic anticoagulation for high thrombotic risk COVID-19 patients to prevent deadly complications.

Prognostic factors in patients with acute mesenteric ischemia-novel tools for determining patient outcomes

BACKGROUND

Acute mesenteric ischemia (AMI) is a devastating disease with poor prognosis. Due to the multitude of underlying factors, prediction of outcomes remains poor. We aimed to identify factors governing diagnosis and survival in AMI and develop novel prognostic tools.

METHODS

This monocentric retrospective study analyzed patients with suspected AMI undergoing imaging between January 2014 and December 2019. Subgroup analyses were performed for patients with confirmed AMI undergoing surgery. Nomograms were calculated based on multivariable logistic regression models.

RESULTS

Five hundred and thirty-nine patients underwent imaging for clinically suspected AMI, with 216 examinations showing radiological indication of AMI. Intestinal necrosis (IN) was confirmed in 125 undergoing surgery, 58 of which survived and 67 died (median 9 days after diagnosis, IQR 22). Increasing age, ASA score, pneumatosis intestinalis, and dilated bowel loops were significantly associated with presence of IN upon radiological suspicion. In contrast, decreased pH, elevated creatinine, radiological atherosclerosis, vascular occlusion (versus non-occlusive AMI), and colonic affection (compared to small bowel ischemia only) were associated with impaired survival in patients undergoing surgery. Based on the identified factors, we developed two nomograms to aid in prediction of IN upon radiological suspicion (C-Index = 0.726) and survival in patients undergoing surgery for IN (C-Index = 0.791).

CONCLUSION

As AMI remains a condition with high mortality, we identified factors predicting occurrence of IN with suspected AMI and survival when undergoing surgery for IN. We provide two new tools, which combine these parameters and might prove helpful in treatment of patients with AMI.

Chronic mesenteric ischemia: causes, methods of diagnosis and treatment

Chronic mesenteric ischemia (CMI) is an urgent public health problem. The long asymptomatic course of the disease, sudden onset and an unfavorable prognosis in the absence of treatment make it necessary to pay closer attention to this pathology. There are currently two competitive treatments for CMI: surgical and endovascular revascularization. Despite numerous studies comparing these methods, the question of which one is more effective and reliable remains open. The review includes current data from clinical trials and meta-analyses demonstrating the advantages and disadvantages of both methods.

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.

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.

Evaluation of Suspected Small Bowel Ischemia Using Contrast-Enhanced Ultrasound with Computed Tomography Fusion

Small bowel ischemia can lead to fatal complications such as necrosis, perforation, and sepsis. Clinical examinations and laboratory tests are usually inconclusive in critically ill patients. The need for surgical exploration is decided based on imaging, examination, and clinical judgment. The decision to operate is time-critical and can be lifesaving, but surgical intervention has the potential to cause additional morbidity, especially in unstable patients. Contrast-enhanced computed tomography (CECT) is the study of choice in suspected small bowel ischemia but has poor specificity. Contrast-enhanced ultrasound (CEUS) provides real-time visualization of the bowel wall vascularity. In this case report, we used a CEUS with CT fusion examination to rule out small bowel ischemia in a critically ill patient with suspected closed loop small bowel obstruction on CECT and in whom surgical exploration would have not been well tolerated. The patient's condition later improved, and an abdominal CT showed no evidence of obstruction.

Ischemic bowel disease in 2021

Ischemic bowel disease (ISBODI) includes colon ischemia, acute mesenteric ischemia (AMI) and chronic mesenteric ischemia (CMI). Epidemiologically, colon ischemia is the most common type followed by AMI and CMI. There are various risk factors for the development of ISBODI. Abdominal pain is the common presenting symptom of each type. High clinical suspicion is essential in ordering appropriate tests. Imaging studies and colonoscopy with biopsy are the main diagnostic tests. Treatment varies from conservative measures to surgical resection and revascularization. Involvement of multidisciplinary team is essential in managing ISBODI. Although open surgery with revascularization plays an important role, recently there is an increasing interest in percutaneous endovascular treatment.

Problem-solving with MRI in acute abdominopelvic conditions, part 2: gynecological, obstetric, vascular, and renal diseases

The purpose of this article is to illustrate the benefits of magnetic resonance imaging (MRI) in the setting of abdominopelvic emergencies. Owing to intrinsically high soft-tissue contrast resolution, and ability to resolve different soft tissue, MRI holds notable advantages over other imaging modalities and can be used as a problem-solving tool. Additional advantages of MRI include lack of radiation-related risks to children and pregnant women, and the ability to acquire detailed diagnostic information even without intravenous contrast which can be beneficial in patients with contrast allergy and end-stage renal disease. In the part 2, the authors focus on MRI features of female pelvic gynecological diseases, pregnancy- related complications, abdominal vascular complications, and renal diseases.

Relationship of superior mesenteric artery thrombus density with transmural intestinal necrosis on multidetector computed tomography in acute mesenteric ischemia

BACKGROUND

Acute arterial occlusive mesenteric ischemia with transmural intestinal necrosis (TIN) is a fatal disease, which is difficult to diagnose on multidetector computed tomography (MDCT). The aim of the present study was to determine the relationship of superior mesenteric artery (SMA) thrombus density with TIN on MDCT in patients with acute mesenteric ischemia (AMI) due to SMA thromboembolism.

METHODS

In this retrospective study, 33 patients who underwent abdominal MDCT and angiography for AMI due to SMA thromboembolism were divided into two groups: the AMI with TIN group and the AMI without TIN group. We analyzed the relationships of clinical characteristics, qualitative MDCT signs, and SMA thrombus density with TIN. The SMA thrombus density was measured on non-contrast MDCT. Univariate and multivariate analyses were performed to determine the risk factors for predicting TIN. The diagnostic performances of risk factors were evaluated by receiver-operating characteristic (ROC) curve analysis.

RESULTS

Of the patients with AMI enrolled in this study, 33.3% (11/33) were diagnosed with TIN. Peritonitis (P=0.042), bowel wall thinning (P=0.033), and pneumatosis/portomesenteric gas (P=0.010) were significantly associated with TIN. AMI patients with TIN exhibited a higher SMA thrombus density than AMI patients without TIN [41.2±6.1 vs. 34.2±3.0 Hounsfield unit (HU), P=0.003]. Multivariate analysis showed that SMA thrombus density was an independent predictor of TIN [P=0.044, hazard ratio (HR): 1.82, 95% confidence interval (CI): 1.02-3.25]. For diagnosing AMI with TIN, the area under the ROC curve (AUC) of SMA thrombus density (0.83) was larger than those of peritonitis (0.68), bowel wall thinning (0.66), and pneumatosis/portomesenteric gas (0.71).

CONCLUSIONS

In patients with AMI, erythrocyte-rich thrombus blocking the SMA trunk which has a higher density on MDCT is prone to the occurrence of TIN compared with erythrocyte-scarce thrombus with a lower density. SMA thrombus density could be an independent risk factor for TIN in patients with AMI due to SMA thromboembolism.

Endovascular therapy in acute mesenteric ischemia after coronary artery bypass grafting: a case report and literature review

In the pattern of abdominal complications after cardiac surgery, acute mesenteric ischemia is rare but high-mortality pathology. In the initial stages, the disease has no specific signs, which makes it difficult to perform early multislice computed tomography to diagnose it. Risk stratification and an individual approach to the choice of diagnostic and therapeutic measures aimed at early restoration of mesenteric blood flow will reduce the mortality in this complication.

Small bowel radiology

PURPOSE OF REVIEW

Recent advances in computed tomography (CT), ultrasound (US), magnetic resonance imaging (MRI), and nuclear radiology have improved the diagnosis and characterization of small bowel pathology. Our purpose is to highlight the current status and recent advances in multimodality noninvasive imaging of the small bowel.

RECENT FINDINGS

CT and MR enterography are established techniques for small bowel evaluation. Dual-energy CT is a novel technique that has shown promise for the mesenteric ischemia and small bowel bleeding. Advanced US techniques and MRI sequences are being investigated to improve assessment of bowel inflammation, treatment response assessment, motility, and mural fibrosis. Novel radiotracers and scanner technologies have made molecular imaging the new reference standard for small bowel neuroendocrine tumors. Computational image analysis and artificial intelligence (AI) have the potential to augment physician expertise, reduce errors and variability in assessment of the small bowel on imaging.

SUMMARY

Advances in translational imaging research coupled with progress in imaging technology have led to a wider adoption of cross-sectional imaging for the evaluation and management of small bowel entities. Ongoing developments in image acquisition and postprocessing techniques, molecular imaging and AI have the strongest potential to transform the care and outcomes of patients with small bowel diseases.

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.

Endovascular Revascularization with Stent Implantation in Patients with Acute Mesenteric Ischemia due to Acute Arterial Thrombosis: Clinical Outcome and Predictive Factors

Purpose

To determine 30-day-mortality rates and identify predictors for survival in patients undergoing endovascular revascularization for acute mesenteric ischemia (AMI) due to occlusion of the celiac (CA) or superior mesenteric artery (SMA) from arterial thrombosis in the setting of atherosclerosis at the vessel origin.

Materials and Methods

A retrospective analysis on patients who underwent acute endovascular revascularization to treat AMI caused by thrombotic occlusion of the CA and/or SMA between January 2011 and December 2019 was conducted. 30-day-mortality rates were calculated. Univariate binomial logistic regression analyses (p < 0.05) were performed to assess whether the following factors were associated with 30-day mortality: sex, age, history of smoking, history of abdominal angina, signs of bowel necrosis on pre-interventional CT, one- vs. two-vessel disease, patency of the inferior mesenteric artery, outpatient or inpatient occurrence of ischemia, onset of AMI during ITU stay, elevated pre-interventional serum lactate levels, total leukocyte count, platelet/lymphocyte ratio and neutrophil/lymphocyte ratio.

Results

40 patients were included in this analysis. 30-day-mortality rate was 25/40 (62.5%). Median overall survival of patients who survived the first 30 days was 36 ± 18 months. None of the analyzed factors was statistically significantly associated with 30-day mortality.

Conclusion

Although mortality of patients with AMI due to acute arterial thrombosis remains high, almost 40% of patient who underwent emergent endovascular revascularization survived longer than one month. Since no predictors for the outcome in these patients were identified, all patients with AMI should be offered an immediate revascularization effort.

Defining Duplex Ultrasound Criteria for In-Stent Restenosis of the Superior Mesenteric Artery

BACKGROUND

This study sought to define duplex ultrasound (DUS) velocity criteria predicting ≥70% stenosis in superior mesenteric artery (SMA) stents by correlating in-stent peak systolic velocity (PSV) with computed tomographic angiography (CTA) measurements of percent stenosis.

METHODS

A retrospective review of 109 patients undergoing SMA stenting between 2003 and 2018 was conducted at a single institution. Thirty-seven surveillance duplex ultrasound studies were found to have a CTA performed within 30 days of study completion. Bare metal (n = 20) and covered stents (n = 17) were included. Velocities were paired to in-stent restenosis (ISR) measured by mean vessel diameter reduction on SMA centerline reconstructions from CTA. Receiver operating characteristic (ROC) curves was generated and logistic regression models for ≥70% ISR probability were used to define velocity criteria in the stented SMA.

RESULTS

At a PSV of 300 cm/sec, the sensitivity is 100% and specificity 80% for a ≥70% in-stent SMA stenosis. At a PSV of 400 cm/sec, the sensitivity and positive predictive value (PPV) is 63% and the specificity and negative predictive value (NPV) is 90%. A PSV of 450 cm/sec was consistent with the highest specificity (100%) and PPV (100%) but lower sensitivity (50%) and NPV (87.9%). One patient with a PSV of 441 cm/sec on surveillance DUS died from complications of acute-on-chronic mesenteric ischemia.

CONCLUSIONS

A PSV of 400 cm/sec on mesenteric DUS can predict ≥70% ISR with high sensitivity and should be considered as a diagnostic threshold for SMA in-stent restenosis.

Pneumatosis intestinalis with pneumoperitoneum: Not always a surgical emergency

Pneumatosis intestinalis (PI) and pneumoperitoneum are commonly recognized as severe signs of gastrointestinal diseases that require emergency surgery. However, these symptoms can also be caused by benign conditions. We describe 4 cases of benign PI and pneumoperitoneum that were detected in different clinical situations (accidental discovery in bilan of aortic dissection (case #1), bilateral pulmonary embolism (case #2), overflow diarrhea due to fecal impaction (case #3), and in follow-up postbiliary digestive anastomosis surgery (case #4), which were addressed with exploratory surgery (case #1) or conservative treatment (the remaining cases), with favorable outcomes. Because PI and pneumoperitoneum can be associated with both life-threatening causes and benign conditions, treatment decisions should be based on the correspondence between clinical and paraclinical features, rather than imaging alone.

Amphetamine-induced small bowel ischemia - A case report

Nonocclusive mesenteric ischemia is most common in elderly patients with multiple comorbidities. Nevertheless, there are some reports of acute bowel ischemia in young patients with a history of recreational drug abuse. We describe the case of a 33-year-old patient who presented with acute abdominal pain following amphetamine consumption. Multidetector computed tomography showed nonocclusive segmental ischemia of the distal ileum, and the patient underwent emergency surgery with ileocecal resection. The patient recovered quickly and was discharged without any postoperative complications. An early and precise diagnosis of patients with intestinal ischemia having a history of amphetamine abuse is of utmost importance for prompt and proper treatment. Especially in younger patients, multidetector computed tomography should be tailored to use with less radiation. A single portal venous scan proved sufficient in our case.