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

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.

Nonocclusive Mesenteric Ischemia Is a Potentially Lethal Complication Just after Stroke Onset: Report of Six Case Studies

Nonocclusive mesenteric ischemia (NOMI) is a rare but life-threatening post-stroke complication. This is the first case series report of NOMI after stroke, describing its characteristics and the difficulty of diagnosis. We retrospectively reviewed 367 stroke patients from April 2018 to May 2019 in our hospital. We identified six patients (1.6%) with NOMI after stroke and described their clinical presentation, including characteristics, vital signs, laboratory parameters, treatment, and outcomes. The mean interval between stroke onset and diagnosis of NOMI was 4.6 days (range, 3–10 days). Five patients had disturbance of consciousness caused by stroke, and therefore the major complaints and symptoms associated with NOMI were nonspecific, possibly resulting in delayed diagnosis and treatment. All patients had a high respiratory rate (≥22 breaths/min). C-reactive protein and lactate levels were high (mean, 21.6 mg/L and 2.4 mmol/L, respectively). All patients underwent emergent abdominal operations. Four patients were discharged with modified Rankin Scale scores ≥4, and two patients died. NOMI can be a fatal post-stroke complication and is challenging to diagnose. Further investigations should be conducted to determine the most efficient way to diagnose NOMI after stroke.

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.

Large Bowel Ischemia/Infarction: How to Recognize It and Make Differential Diagnosis? A Review

Ischemic colitis represents the most frequent form of intestinal ischemia occurring when there is an acute impairment or chronic reduction in the colonic blood supply, resulting in mucosal ulceration, inflammation, hemorrhage and ischemic necrosis of variable severity. The clinical presentation is variable and nonspecific, so it is often misdiagnosed. The most common etiology is hypoperfusion, almost always associated with generalized atherosclerotic disease. The severity ranges from localized and transient ischemia to transmural necrosis of the bowel wall, becoming a surgical emergency, with significant associated morbidity and mortality. The diagnosis is based on clinical, laboratory suspicion and radiological, endoscopic and histopathological findings. Among the radiological tests, enhanced-CT is the diagnostic investigation of choice. It allows us to make the diagnosis in an appropriate clinical setting, and to define the entity of the ischemia. MR may be adopted in the follow-up in patients with iodine allergy or renal dysfunctions, or younger patients who should avoid radiological exposure. In the majority of cases, supportive therapy is the only required treatment. In this article we review the pathophysiology and the imaging findings of ischemic colitis.

Influence of clinical suspicion on CT accuracy of acute mesenteric ischemia: Retrospective study of 362 patients

PURPOSE

Acute mesenteric ischemia (AMI) may be underdiagnosed when not clinically suspected before CT is performed. We assessed the influence of a clinical suspicion of AMI on the CT accuracy.

METHOD

This retrospective single-centre study included patients who underwent CT in 2014-2019 and had clinically suspected AMI and/or confirmed AMI. CT protocols were adapted based on each patient's presentation and on findings from unenhanced images. The CT protocol was considered optimal for AMI when it included arterial and portal venous phases. CT protocols, accuracy of reports, and outcomes were compared between the groups with and without suspected AMI before CT.

RESULTS

Of the 375 events, 337 (90 %) were suspected AMI and 66 (18 %) were AMI, including 28 (42 %) with and 38 without suspected AMI. These two groups did not differ significantly regarding the medical history, clinical presentation, or laboratory tests. The CT protocol was more often optimal for AMI in the group with suspected AMI (26/28 [93 %] vs. 28/38 [74 %], p = 0.046). Diagnostic accuracy was not different between groups with and without suspected AMI (26/28 [93 %] vs. 34/38 [90 %], p = 1.00). However, it was lower in the group without suspicion of AMI when the CT protocol was not optimal for AMI (27/28 [96 %] vs 7/10 [70 %], p = 0.048).

CONCLUSIONS

The negative influence of not clinically suspecting AMI can be mitigated by using a tailored CT protocol.