Radiological predictive factors of transmural intestinal necrosis in acute mesenteric ischemia: systematic review and meta-analysis

Acute arterial mesenteric ischaemia: comparison of partial and complete occlusion of the superior mesenteric artery

OBJECTIVES

To describe the characteristics and outcomes of patients with an incomplete occlusion of the superior mesenteric artery (SMA) (persistence of contrast-enhanced vessel lumen) and compare them to those with a complete occlusion of the SMA (complete interruption of the contrast-enhanced vessel lumen) in arterial acute mesenteric ischaemia (AMI).

MATERIAL AND METHODS

Retrospective study of arterial AMI patients (2006-2022). Demographics, laboratory tests, clinical characteristics, CT, treatments and outcomes were compared between patients with complete or incomplete SMA obstruction after adjusting for aetiology (embolic or atherosclerotic). The primary outcome was 30-day mortality, and the secondary outcome was 6-month gastrointestinal disability-free survival (no short bowel syndrome or parenteral nutritional support or permanent stoma).

RESULTS

151 patients (65 women, mean age 69) were included, 62 (41%) with incomplete and 89 (59%) with occlusive SMA occlusion. After adjusting for aetiology, chronic kidney failure (p = 0.03) and normal bowel enhancement on CT (p < 0.01) were associated with incomplete SMA occlusion. Patients with incomplete SMA occlusion were more frequently treated by endovascular revascularisation (p < 0.01) and stenting (p < 0.01), while patients with complete SMA occlusion were treated by open revascularisation. The 30-day mortality rate was 13% with no difference between incomplete (11%) and complete SMA occlusion (15%; p = 0.89). Nevertheless, complete SMA occlusion patients had a lower 6-month gastrointestinal disability-free survival rate (p = 0.01), more transmural necrosis (p < 0.01) and a higher risk of gastrointestinal disability (p = 0.02).

CONCLUSION

Incomplete SMA occlusion can cause AMI with a similar 30-day mortality rate to completely occlusive forms. However, it is associated with poorer gastrointestinal outcomes, regardless of aetiology.

CRITICAL RELEVANCE STATEMENT

Acute arterial mesenteric ischaemia caused by incomplete occlusion of the superior mesenteric artery demonstrates similar 30-day mortality to complete occlusion but distinctively better gastrointestinal outcomes, emphasising nuanced imaging evaluation for targeted management strategies in these patients.

KEY POINTS

Occlusive acute mesenteric ischaemia can be caused by incomplete superior mesenteric artery (SMA) occlusion. Acute mesenteric ischaemia caused by incomplete SMA occlusion has a similar 30-day mortality rate to complete SMA occlusion. A complete occlusion of the SMA is associated with poorer gastrointestinal outcomes.

Selective minimally invasive strategy for acute superior mesenteric artery obstruction

OBJECTIVE

Acute mesenteric artery obstruction is a severe cause of acute mesenteric ischemia, associated with significant morbidity and mortality. However, there is limited guidance on choosing between traditional and minimally invasive techniques comprehensively. This study introduces a selective, minimally invasive strategy designed to improve the survival and prognosis of patients with acute superior mesenteric artery obstruction.

METHODS

In this prospective, single-arm trial conducted between 2020 and 2023, patients with acute mesenteric ischemia due to acute superior mesenteric artery obstruction were enrolled. A total of 42 patients were included, meeting the predetermined sample size. The primary outcome was the 30-day chronic intestinal failure (CIF)-free survival rate. Based on an algorithm incorporating preoperative radiographic findings, physical signs, and laboratory markers, patients were assigned to one of three therapeutic pathways: traditional laparotomy with thrombectomy, laparoscopy combined with endovascular therapy, or endovascular therapy alone.

RESULTS

The CIF-free survival rates at 30 days and 2 years were 71% (30/42) and 60%, respectively. Short-term mortality, including 30-day and in-hospital mortality, was 11.9%, indicating an improvement compared with historical cohorts. The cumulative mortality rates at 6 months, 1 year, and 2 years were 26%, 32%, and 32%, respectively. The primary and assisted patency rates at 1 year were 90% and 97%, respectively. Transition to laparotomy was required in 43% of patients undergoing laparoscopic exploration. Improved blood supply was observed in 73% of the patients who underwent two laparoscopic procedures (15 patients), and bowel resection was avoided in 40% of cases. The median durations of hospitalization and intensive care unit stay were 19 days (interquartile range, 11-31 days) and 2 days (interquartile range, 0-6 days), respectively.

CONCLUSIONS

This selective, minimally invasive strategy for managing acute mesenteric ischemia demonstrated high 30-day CIF-free survival rates and reduced short-term mortality. These findings suggest the potential advantages of this approach in improving outcomes for patients with acute mesenteric ischemia.

Prognostic Value of the HCO3-to-Lactate Ratio in Acute Mesenteric Ischemia: A Retrospective Analysis

BACKGROUND

Acute mesenteric ischemia (AMI) is a life-threatening emergency with persistently high mortality rates, requiring improved tools for perioperative risk assessment. This study investigates the real-world outcomes of patients with occlusive arterial AMI undergoing surgery, focusing on predictors of short-term mortality.

METHODS

A retrospective, single-center analysis was conducted on patients undergoing emergent mesenteric surgery for occlusive arterial AMI between January 2015 and May 2024. The primary outcome was 30-day survival; secondary outcomes included predictors of in-hospital mortality based on preoperative laboratory parameters.

RESULTS

Sixty patients (mean age 75 ± 12 years) were included, with a 30-day survival rate of 45%. Of the 60 patients, 15 (75%) with acute-on-chronic symptoms (n = 20) survived, compared to 12 (30%) with acute onset (n = 40) (P = 0.003). Multivariate Cox regression identified lactate, bicarbonate (HCO3), the HCO3-to-lactate ratio, and neutrophil count as predictors of 30-day mortality. The HCO3-to-lactate ratio ≤10 demonstrated high predictive accuracy (area under the curve 0.832, sensitivity 90.6%, specificity 75%). In acute-onset cases, excluding acute-on-chronic symptoms improved specificity to 100%.

CONCLUSION

The HCO3-to-lactate ratio is a robust prognostic marker in occlusive arterial AMI, reflecting both tissue hypoperfusion and impaired metabolic compensation. These findings support its potential utility in risk stratification and in guiding clinical decision-making in the emergent management of AMI.

Radiological diagnosis of acute mesenteric ischemia in adult patients: a systematic review and meta-analysis

Computed tomography (CT) is widely used in diagnosing acute mesenteric ischemia (AMI), but robust identification of distinctive subtypes and stages of progression is lacking. Systematic literature search in PubMed, Cochrane Library, Web of Science and Scopus was conducted in May 2024. Studies including at least 10 adult patients and reporting radiological diagnosis of AMI versus no AMI or transmural ischemia versus no transmural ischemia were included. Meta-analyses on sensitivity and specificity of different radiological features in diagnosing AMI were conducted. From 2628 titles, 490 studies underwent full text review, and 81 were included in 14 meta-analyses. Diagnostic accuracy of CT angiography (CTA) was high - sensitivity of 92.0% and specificity of 98.8% (I2 45% and 79%, respectively), but lower for other CT protocols (sensitivity 75.8 and specificity 90.5; I2 83%). In most included studies, distinction of subtypes and severity of AMI (non-transmural or transmural) was not possible. Amongst the non-vascular features, absent/reduced bowel wall enhancement provided the best prognostic value (sensitivity 57.9 and specificity 90.1). CTA is the method of choice for diagnosing AMI with high diagnostic accuracy. None of the non-vascular features alone is sufficiently reliable to diagnose AMI or its progression to transmural necrosis, whereas a combination of different radiological features conveys a potential.

Combining clinical and radiological features improves prediction of bowel ischemia in patients with CT findings of pneumatosis intestinalis

BACKGROUND

Pneumatosis intestinalis on CT presents a diagnostic dilemma, because it could reflect bowel ischemia or benign finding.

PURPOSE

To determine radiological and clinical features that can predict bowel ischemia in patients with pneumatosis intestinalis on CT.

MATERIALS AND METHODS

Patients with "pneumatosis" in abdominal CT reports performed between 1/1/2002 and 12/31/2018 were retrospectively included. Pneumatosis intestinalis was confirmed by review of images. Radiological features of pneumatosis, laboratory data, clinical signs and symptoms were collected. Pathologic pneumatosis intestinalis (PPI) was defined as presence of ischemic (viable or dead) bowel on surgery or death during admission or within 30 days of discharge due to ischemia. Univariate statistical analysis was used to identify features associated with PPI, followed by multivariate logistic regression models.

RESULTS

A total of 313 consecutive patients with pneumatosis intestinalis (162 (52%) men, median age 67 years, IQR 55-78 years) were included. Pathologic pneumatosis intestinalis was present in 114/313 (36%) patients. Presence of arterial or venous thrombosis, porto-mesenteric gas, fat stranding, and location in the small bowel were significantly associated with PPI. A combined clinical and radiological model, which included age, WBC, creatinine, abdominal distention, rebound or guarding, shock, presence of porto-mesenteric gas and fat stranding showed an AUC of 0.85 for prediction of PPI, higher than models using clinical (AUC = 0.80, p = 0.005) or radiological factors (AUC = 0.80, p < 0.0001) alone.

CONCLUSION

Improved prediction of pathological pneumatosis intestinalis can be achieved by a model incorporating both clinical and radiological features (AUC = 0.85)rather than by either clinical (AUC = 0.80) or radiological (AUC = 0.80) features alone.

Deep learning-assisted diagnosis of acute mesenteric ischemia based on CT angiography images

Purpose

Acute Mesenteric Ischemia (AMI) is a critical condition marked by restricted blood flow to the intestine, which can lead to tissue necrosis and fatal outcomes. We aimed to develop a deep learning (DL) model based on CT angiography (CTA) imaging and clinical data to diagnose AMI.

Methods

A retrospective study was conducted on 228 patients suspected of AMI, divided into training and test sets. Clinical data (medical history and laboratory indicators) was included in a multivariate logistic regression analysis to identify the independent factors associated with AMI and establish a clinical factors model. The arterial and venous CTA images were utilized to construct DL model. A Fusion Model was constructed by integrating clinical factors into the DL model. The performance of the models was assessed using receiver operating characteristic (ROC) curves and decision curve analysis (DCA).

Results

Albumin and International Normalized Ratio (INR) were associated with AMI by univariate and multivariate logistic regression (P < 0.05). In the test set, the area under ROC curve (AUC) of the clinical factor model was 0.60 (sensitivity 0.47, specificity 0.86). The AUC of the DL model based on CTA images reached 0.90, which was significantly higher than the AUC values of the clinical factor model, as confirmed by the DeLong test (P < 0.05). The Fusion Model also showed exceptional performance in terms of AUC, accuracy, sensitivity, specificity, and precision, with values of 0.96, 0.94, 0.94, 0.95, and 0.98, respectively. DCA indicated that the Fusion Model provided a greater net benefit than those of models based solely on imaging and clinical information across the majority of the reasonable threshold probabilities.

Conclusion

The incorporation of CTA images and clinical information into the model markedly enhances the diagnostic accuracy and efficiency of AMI. This approach provides a reliable tool for the early diagnosis of AMI and the subsequent implementation of appropriate clinical intervention.

When Is Laparotomy for Mesenteric Ischemia After Aortic Dissection Futile?

BACKGROUND

Tissue necrosis from persistent mesenteric ischemia after aortic dissection may progress to sepsis and death without emergency laparotomy. However, the signs of mesenteric necrosis are common in patients experiencing nonsurvivable multisystem failure after aortic catastrophe. This study examined when and whether laparotomy offers a chance for meaningful survival in these patients.

METHODS

A total of 145 patients treated for acute type A or type B aortic dissection with mesenteric ischemia were identified from a single institution from 2006 to 2022. Of those patients, 29 underwent laparotomy, all for compelling clinical indications. Detailed clinical characteristics were studied with respect to short- and long-term outcomes in these patients.

RESULTS

Among the patients who underwent laparotomy, 45% (13 of 29) survived to discharge compared with 71% (103 of 145) of all patients with mesenteric malperfusion. Serum lactate and arterial pH were both very strongly associated with survival after laparotomy. Among survivors and nonsurvivors, the mean lactate level before laparotomy was 6.3 mmol/L vs 13.4 mmol/L (P = .024), and the mean pH was 7.39 vs 7.20 (P < .001). In particular, a lactate value higher than 8 mmol/L (odd ratio, 16.5; 95% CI, 2.0-192; P = .003) and a pH lower than 7.30 (odds ratio, 14.4; 95% CI, 1.87-128; P = .003) were highly predictive of mortality. Survival to discharge after laparotomy for patients with both severe lactatemia and severe acidosis (defined earlier) was 9% (1 of 11) compared with 90% (9 of 10) for patients with neither severe lactatemia nor acidosis.

CONCLUSIONS

The degree of lactic acidosis can effectively identify patients for whom laparotomy is futile and those for whom it is not after aortic dissection with mesenteric ischemia.

Diagnostic Performance of Clinical and Routine Laboratory Data in Acute Mesenteric Arterial Occlusion-An International Multicenter Study

BACKGROUND

There are no clinical or laboratory markers that can diagnose acute mesenteric ischemia (AMI) accurately. This study aimed to find differences in clinical and laboratory markers between arterial occlusive AMI and other acute abdominal diseases where AMI was initially suspected.

METHODS

This was a post hoc study of an international prospective multicenter study where data on patients with suspected AMI were collected. Independent factors associated with arterial occlusive AMI were evaluated in a multivariable logistic regression analysis.

RESULTS

The number of patients with arterial occlusive AMI was 231, consisting of thrombotic (n = 104), embolic (n = 61), and indeterminate (n = 66) occlusions. The non-AMI group included 287 patients, of whom 128 had strangulated bowel obstruction. Current smoking (odds ratio [OR] 2.56, 95% confidence interval [CI] 1.31-5.03), hypertension (OR 2.08, 95% CI 1.09-3.97), bowel emptying (OR 3.25, 95% CI 1.59-6.63), and leukocytosis (OR 1.54, 95% CI 1.14-2.08) at admission were independently associated with arterial occlusive AMI compared to the non-AMI group.

CONCLUSIONS

This study found clinical and laboratory data to be associated with arterial occlusive AMI in patients with suspicion of AMI, which can possibly be of value in screening for arterial occlusive AMI at the emergency department. Further studies are needed to find more accurate diagnostic markers.

Irreversible Transmural Intestinal Necrosis in Acute Mesenteric Ischemia: Retrospective Cohort Study from a High-Volume Hospital

Background: Owing to the low incidence rate and nonspecific symptoms of acute mesenteric ischemia (AMI), the identification and prediction of irreversible transmural intestinal necrosis (ITIN) and extensive bowel resection (≥100 cm) (EBR) are difficult and critical. This study aimed to investigate the risk factors for ITIN and EBR in patients with AMI. Methods: The clinical data of 254 AMI patients were retrospectively analyzed. Furthermore, the incidence of ITIN and EBR were set as dependent variables, and relevant risk factors were screened using univariate and multivariate logistic regression analyses. The comparisons of surgical characteristics and postoperative recovery outcomes between the EBR and control group were also conducted. Results: The presence of hemorrhagic (odds ratio [OR] = 28.356, P < .001) or other types ascites (OR = 13.051, P = .003), peritonitis (OR = 8.463, P = .005), intestinal diameter >2.35 cm (OR = 5.493, P = .020), and serum creatinine (CREA) >95 μmol/L (OR = 4.866, P = .048) were identified as independent risk factors for ITIN in patients with AMI. In addition, serum C-reactive protein (CRP) >15 mg/L (OR = 38.023, P = .006), and CREA >100 μmol/L (OR = 6.248, P = .035) were proved to be independently associated with EBR for ITIN cases. Compared to the control group, EBR significantly increased the likelihood of requiring enterostomy (P = .001), blood transfusion (P = .002), and transfer to intensive care unit (P = .016), while also prolonging the recovery time for intestinal function (P = .014). Conclusions: The presence of ascites, peritonitis, intestinal diameter >2.35 cm, and serum CREA >95 μmol/L were independently correlated with ITIN for AMI cases, while serum CRP >15 mg/L and CREA >100 μmol/L independently increased the risk of EBR.

Predictors of Survival Without Intestinal Resection after First-Line Endovascular Revascularization in Patients with Acute Arterial Mesenteric Ischemia

Background Acute arterial mesenteric ischemia requires emergency treatment and is associated with high mortality rate and poor quality of life. Identifying factors associated with survival without intestinal resection (hereafter, intestinal resection-free [IRF] survival) could help in treatment decision-making after first-line endovascular revascularization. Purpose To identify factors associated with 30-day IRF survival in patients with acute arterial mesenteric ischemia whose first-line treatment was endovascular revascularization. Materials and Methods Patients with acute arterial mesenteric ischemia whose first-line treatment was endovascular revascularization because of a low probability of bowel necrosis were included in this single-center retrospective cohort (May 2014 to August 2022). Patient demographics, laboratory values, clinical characteristics at admission, CT scans, angiograms, and endovascular revascularization-related variables were included. The primary end point was 30-day IRF survival, and secondary end points were 3-month, 1-year, and 3-year overall survival. Factors independently associated with 30-day IRF survival were identified with binary logistic regression. Results A total of 117 patients (median age, 70 years [IQR, 60-77]; 53 female, 64 male) were included. Within 30 days after revascularization, 73 of 117 patients (62%) survived without resection, 28 of 117 (24%) survived after resection, 14 of 117 (12%) died without resection, and two of 117 (2%) underwent resection but died. The 30-day IRF survival was 63% (74 of 117). The 3-month, 1-year, and 3-year mortality rate was 18% (21 of 117), 21% (25 of 117), and 27% (32 of 117), respectively. Independent predictors of 30-day IRF survival were persistent bowel enhancement at initial CT (odds ratio [OR], 0.3; 95% CI: 0.2, 0.8; P = .013) and C-reactive protein (CRP) level less than 100 mg/L (OR, 0.3; 95% CI: 0.1, 0.8; P = .002). The 30-day IRF survival was 86%, 61%, 47%, and 23% in patients with both favorable features, persistent bowel enhancement but CRP level greater than 100 mg/L, no bowel enhancement but CRP level less than 100 mg/L, and both unfavorable features, respectively. Conclusion Independent predictors associated with 30-day IRF survival in patients with acute arterial mesenteric ischemia whose first-line treatment was endovascular revascularization were persistent bowel wall enhancement at initial CT and CRP level less than 100 mg/L. © RSNA, 2024 Supplemental material is available for this article.

Future Perspectives on Radiomics in Acute Liver Injury and Liver Trauma

Background: Acute liver injury occurs most frequently due to trauma, but it can also occur because of sepsis or drug-induced injury. This review aims to analyze artificial intelligence (AI)'s ability to detect and quantify liver injured areas in adults and pediatric patients. Methods: A literature analysis was performed on the PubMed Dataset. We selected original articles published from 2018 to 2023 and cohorts with ≥10 adults or pediatric patients. Results: Six studies counting 564 patients were collected, including 170 (30%) children and 394 adults. Four (66%) articles reported AI application after liver trauma, one (17%) after sepsis, and one (17%) due to chemotherapy. In five (83%) studies, Computed Tomography was performed, while in one (17%), FAST-UltraSound was performed. The studies reported a high diagnostic performance; in particular, three studies reported a specificity rate > 80%. Conclusions: Radiomics models seem reliable and applicable to clinical practice in patients affected by acute liver injury. Further studies are required to achieve larger validation cohorts.

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.

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.

Small bowel transmural necrosis secondary to acute mesenteric ischemia and strangulated obstruction: CT findings of 49 patients

Rationale and objectives

Transmural bowel necrosis (TBN) is an uncommon surgical emergency that represents an endpoint of occlusive acute mesenteric ischemia (AMI), nonocclusive AMI and small bowel obstruction (SBO). According to limited evidence, each etiology of TBN might demonstrate a different CT finding. This investigation aimed to 1) identify overall CT findings of TBN, and 2) compare CT findings of TBN in each etiology.

Materials and methods

Forty-nine consecutive adults (mean age, 64.6 years; 26 men) with occlusive AMI, nonocclusive AMI or SBO, and pathologically proven TBN were enrolled. All had a CT scan within 24 h before surgery. Clinical information was compiled from medical records. CT examinations were re-reviewed by two radiologists with disagreements resolved by the third radiologist. Data were analyzed and compared.

Results

Transmural bowel necrosis were secondary to arterial AMI, venous AMI, combined arterial and venous AMI, nonocclusive AMI, and SBO in 6, 5, 2, 10, and 26 patients, respectively. The CT findings were ascites (93.9%), abnormal wall enhancement (91.8%), bowel dilatation (89.8%), mesenteric fat stranding (89.8%), abnormal wall thickness (71.5%), pneumatosis (46.9%) and intrinsic hyperattenuation of bowel walls (22.5%). Portovenous gas, mesenteric venous gas, and pneumoperitoneum were present in 4 patients (8.2%). Bowel wall thickness was the only CT findings that showed a statistically significant difference among the 5 etiologies of TBN (P = 0.046).

Conclusions

Most common CT findings of TBN were ascites, abnormal bowel wall enhancement, dilatation, and mesenteric fat stranding. Wall thickness differentiated five etiologies, being most thickened in venous AMI and normal in arterial AMI.