Ischemia and infarction of the small bowel and colon: spectrum of imaging findings

Conservative Versus Endovascular Treatment for Spontaneous Isolated Superior Mesenteric Artery Dissection: A Clinical and Imaging Follow-up Study

PURPOSE

Spontaneous isolated superior mesenteric artery dissection (SISMAD) is a rare vascular disease, the treatment strategies for which remain debated. This retrospective study aimed to compare the outcomes of conservative and endovascular treatments in patients with SISMAD.

MATERIALS AND METHODS

Fifty-eight patients with SISMAD confirmed by computed tomography angiography admitted to our hospital between November 2017 and May 2021 and received confirmed conservative (n=43) or endovascular (n=15) treatment. The patient demographics, imaging analysis, and follow-up results were analyzed and compared.

RESULTS

The cohort included 54 males and 4 females with a mean age of 52 years. Abdominal pain was the major complaint (49/58, 84.5%), followed by chest pain (2/58, 3.4%). The mean follow-up was 9.1±7.9 months. The 2 main Sakamoto types were type III (27/58, 46.6%) and type IV (16/58, 27.6%). Most patients in both groups had angle 1 (aortomesenteric angle) and angle 2 (superior mesenteric artery [SMA] course) of over 80°. About 67.3% of patients had long length of dissection (>60 mm). The median distance between the SMA root and the dissection entry site was 1.5 cm, mostly (84.5% of the patients) in the curved segment of the SMA. Telephone follow-ups found that most patients survived pain-free, and none underwent intestinal resection. Only 4 patients, 2 in each group, had recurrent abdominal pain during follow-up and received stenting treatment to achieve complete vascular remodeling. Importantly, we found that the conservative and endovascular therapies achieved similar high remodeling rates (94% and 100%, respectively; p=0.335). The conservative group achieved satisfying vascular remodeling (partial, 35%; complete, 59%), making it as safe and effective a treatment as endovascular therapy.

CONCLUSIONS

Initial conservative management is safe and effective in patients with SISMAD. A high technical success rate and favorable short-term outcomes were associated with endovascular procedures as secondary interventions. It would be helpful to conduct large-scale, prospective, randomized controlled trials with long-term follow-up for SISMAD.

CLINICAL IMPACT

1. This research provided more detail clinical information, such as evaluation of abdominal pain and measurements of SMA angles, which is all relevant to treatment. 2. What's more, the most surprising results of follow-up part shown that conservative treatment could reached the remodeling rate as high as endovascular treatment, which was relatively low in other studies. It helps us share our treatment experience with clinicians. 3. In addition, we get limited knowledge about this rare disease, it's encouraging us to do more researches based on the results we had.

Surgical complications of oncological treatments: A narrative review

Gastrointestinal complications are common in patients undergoing various forms of cancer treatments, including chemotherapy, radiation therapy, and molecular-targeted therapies. Surgical complications of oncologic therapies can occur in the upper gastrointestinal tract, small bowel, colon, and rectum. The mechanisms of action of these therapies are different. Chemotherapy includes cytotoxic drugs, which block the activity of cancer cells by targeting intracellular DNA, RNA, or proteins. Gastrointestinal symptoms are very common during chemotherapy, due to a direct effect on the intestinal mucosa resulting in edema, inflammation, ulceration, and stricture. Serious adverse events have been described as complications of molecular targeted therapies, including bowel perforation, bleeding, and pneumatosis intestinalis, which may require surgical evaluation. Radiotherapy is a local anti-cancer therapy, which uses ionizing radiation to cause inhibition of cell division and ultimately lead to cell death. Complications related to radiotherapy can be both acute and chronic. Ablative therapies, including radiofrequency, laser, microwave, cryoablation, and chemical ablation with acetic acid or ethanol, can cause thermal or chemical injuries to the nearby structures. Treatment of the different gastrointestinal complications should be tailored to the individual patient and based on the underlying pathophysiology of the complication. Furthermore, it is important to know the stage and prognosis of the disease, and a multidisciplinary approach is necessary to personalize the surgical treatment. The purpose of this narrative review is to describe complications related to different oncologic therapies that may require surgical interventions.

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.

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.

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.

Duplex ultrasound in the early diagnosis of acute mesenteric ischemia: a longitudinal cohort multicentric study

OBJECTIVE

Acute mesenteric ischemia (AMI) is a life-threatening condition requiring time-dependent treatment; thus, early recognition may improve outcomes. We hypothesized that clinician-performed mesenteric vessels duplex ultrasound (DUS) could facilitate early identification of patients with AMI in high-risk patients presenting with abdominal pain.

METHODS

This was a single-operator, observational, prospective cohort study. Patients aged at least 65 presenting to Emergency Departments with acute abdominal pain and no clear diagnosis after an initial work-up were enrolled. All patients underwent multidetector computed tomography and these findings provided the reference standard in this study. DUS of the celiac artery and superior mesenteric artery (SMA) were obtained to measure the peak systolic velocity (PSV) and were performed within 24 h of admission. PSVs outside the normal range were considered to indicate AMI.

RESULTS

Of 49 patients identified, 47 were consented to enrollment and diagnostic images were obtained in 45 (96%). Fifteen patients (33%) had AMI (six occlusive, nine nonocclusive disease). Among these, 12 (80%) had abnormal DUS velocities. SMA PSV showed a sensitivity of 78.57% [95% confidence interval (CI): 49.2-95.34], a specificity of 64.52% (95% CI: 45.37-80.77), a positive predictive value of 50% (95% CI: 28.22-71.78), and a negative predictive value of 86.96% (95% CI: 66.41-97.22) for AMI. DUS had a sensitivity of 100%, a specificity of 64%, and a negative predictive value of 100% for occlusive AMI. Assessment of celiac artery PSV did not improve diagnostic performance.

CONCLUSION

In this single-operator pilot study, mesenteric vessel DUS was performed successfully in the Emergency Department, with a high proportion of diagnostic images obtained. A normal SMA PSV was associated with a low risk of occlusive AMI.

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.

Imaging of Oncologic Emergencies

Oncologic emergencies can be either the result of the primary tumor, its metastasis, a paraneoplastic syndrome or reaction to the chemotherapy. Imaging plays a crucial role in ensuring a prompt diagnosis as well as assisting in the therapeutic management. In this article, we discuss the common thoracic and abdominal oncological emergencies that may be encountered in an emergency department.

Predictors of severity in ischemic colitis: Usefulness of early ultrasonography

PURPOSE

The main objective was to evaluate the usefulness of early ultrasonography for determining prognosis of patients with ischemic colitis.

MATERIALS AND METHODS

We reviewed the histories of patients with diagnosis of ischemic colitis over a period of 11 years. Two hundred twenty nine patients with ischemic colitis were included. Demographic, clinical, laboratory and sonographic findings were retrospectively analyzed. Patients were divided into two groups according to the outcome: mild (those who improved with conservative treatment) or severe (those who died or required surgery), and the findings of each group were compared. In addition, we developed a predictive model of multivariate logistic regression analysis, and then it was validated in a different population of 58 consecutive patients with ischemic colitis.

RESULTS

The mild ischemic colitis group consisted of 184 patients (age 74,7±8,8years), and the severe group of 45 patients (age 78,6±7,7years). More pancolitis (p=0.005), altered pericolic fat (p=0.032) and free fluid (p=0.013) was observed in the severe ischemic colitis group compared with the mild group. Severe ischemic group had lower wall thickness (p=0.020) and higher resistive index than mild group (p=0.025). Multivariate analysis identified as protective factors to severe ischemic colitis: pain (p=0.026), diarrhea (p=0.034), rectal bleeding (p=0.000), and hypertension (p=0.001). Altered pericolic fat (p=0.008) and pancolitis (p=0.017) were sonographic findings significantly related to severe ischemic colitis. Our model correctly classified 88.4% of the study patients and 89.6% of the population of 58 patients used in validation.

CONCLUSIONS

Sonographic features with clinical findings can predict the outcome of ischemic colitis. Our predictive model could differentiate properly between patients with mild or severe ischemic colitis.

Point-of-care ultrasound identification of pneumatosis intestinalis in pediatric abdominal pain: a case report

We describe a case report of an infant with intussusception who presented to a pediatric emergency department with diarrhea and increased irritability. Pneumatosis intestinalis (intra-mural air) detected on point-of-care ultrasonography (but not apparent on plain abdominal radiographs) alerted the emergency physicians towards the severity of disease process.

Intestinal pneumatosis in adults: diagnostic and prognostic value

Intestinal pneumatosis (IP) has been traditionally associated with intestinal infarction and poor outcome in adults; recent studies have questioned its clinical value. To assess its diagnostic and prognostic significance, we have retrospectively evaluated 102 patients correlating the CT finding of gastrointestinal parietal gas with clinical data and outcome. Fifty-three patients (52%) had surgical evidence of intestinal infarction. In the remaining patients, a variety of lesions were found including intestinal obstruction, cancer, volvulus, ulcer, hernia, trauma, Crohn's disease, diverticulitis, and iatrogenic causes. We observed the presence of portal vein gas (PVG) associated to IP in 25.5% of cases. In patients having both IP and PVG, intestinal infarction was observed in 69.2% of cases. In our series, overall mortality was 30.4% (31/102), and when PVG was present, it rose to 50% (13/26). In our study, IP has been observed in a broad range of lesions with very different prognosis, the most frequent of which was intestinal infarction. When associated to PVG, there was a much higher prevalence of intestinal infarct, and the prognosis was definitively worse.

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.

Evaluating Patients with Left Upper Quadrant Pain

Imaging plays a major role in the evaluation of patients who present to the emergency department with acute left upper quadrant (LUQ) pain. Multidetector computed tomography is currently the primary modality used for imaging these patients. The peritoneal reflections, subperitoneal compartment, and peritoneal spaces of the LUQ are key anatomic features in understanding the imaging appearance of acute diseases in this area. Diseases of the stomach, spleen, pancreas, and splenic flexure are encountered in patients with acute LUQ pain. Optimization of the imaging protocol is vital for accurate diagnosis and characterization of these diseases in the acute 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.

Positive Predictive Value of Abdominal Sonography in the Diagnosis of Ischemic Colitis

AIM

The aim was to prospectively evaluate the positive predictive value of ultrasound in the diagnosis of ischemic colitis, with colonoscopy as the reference standard.

METHODS

During a 2-year period we included consecutive patients over 50 years of age with sudden abdominal pain and/or rectal bleeding who underwent abdominal sonography in an emergency setting with a thickened segment of colon with a length of more than 10 cm. This clinical-sonographic triad was considered diagnostic for ischemic colitis. A thickened bowel location or color Doppler flow findings on ultrasound examination were evaluated but were not considered to make the diagnosis of ischemic colitis. Basic descriptive statistics were used to characterize the study patients. The positive predictive value was calculated as: number of patients with the definitive diagnosis of ischemic colitis (colonoscopic or follow-up)/number of patients with a sonographic diagnosis of ischemic colitis.

RESULTS

A total of 48 patients had the clinical-sonographic triad; mean age: 74.3 years (range 54-90 years). The most frequent clinical manifestation was rectal bleeding (83% of the cases) followed by abdominal pain (81%) and diarrhea (45%). A total of 42 cases of ischemic colitis were confirmed by endoscopy (n=35) and biopsy (n=34) or clinical evaluation (n=7). The positive predictive value of the clinical-sonographic diagnosis of ischemic colitis was 87.5%. Thickening of the colon wall was detected on the left side in 35 patients with ischemic colitis, on the right side in 3 and pancolitis was identified in 5 patients.

CONCLUSION

In an appropriate clinical setting, ultrasound has a high positive predictive value for the diagnosis of ischemic colitis.

Colorectal emergencies and related complications: a comprehensive imaging review--imaging of colitis and complications

OBJECTIVE

Colorectal emergencies are a common presentation in the emergency medicine setting and their timely diagnosis plays a crucial role in avoiding dreaded complications. The quintessential role of a radiologist lies in identifying the cause, narrowing the differential diagnosis according to imaging features, and, most importantly, identifying the associated complications.

CONCLUSION

This review focuses on imaging features of the spectrum of colitides and the complications related to colitides.

CT findings in acute, subacute, and chronic ischemic colitis: suggestions for diagnosis

Purpose. This paper aims at evaluating CT findings of occlusive and nonocclusive ischemic colitis (IC), in correlation with the etiology and the different phases of the disease. Materials and Methods. CT examination and clinical history of 32 patients with proven IC were retrospectively reviewed. The CT findings were analyzed according to the different phases of the disease (acute, subacute, and chronic). Results. Among the 32 CT examinations performed in the acute phase, 62.5% did not present signs of occlusion of the superior mesenteric artery (SMA) or inferior mesenteric artery (IMA), whereas IMA occlusion was detected in 37.5% of CT examinations. In the acute phase, the presence of pericolic fluid was found in 100% of patients undergoing progressive resorption from acute to subacute phase if an effective reperfusion occurred; the bowel wall thickening was observed in 28.1% patients in acute phase and in 86.4% patients evaluated in subacute phase. The unthickened colonic wall was found in all conditions where ischemia was not followed by effective reperfusion (71.9% of cases), and it was never found in chronic phase, when the colon appeared irregularly thickened. Conclusion. CT allows determining the morphofunctional alterations associated with the IC discriminating the occlusive forms from the nonocclusive forms. CT, furthermore, allows estimating the timing of ischemic damage.

New and old tools for abdominal imaging in critically ill patients

Diagnostic imaging technology has advanced considerably during the past two decades. Different imaging techniques have been proposed for abdominal imaging in critically ill patients like plain radiography, sonography, computed tomography (CT), magnetic resonance and positron emission tomography. Sonography has been proven to be effective to detect free intra-peritoneal fluid and it is considered one of the primary diagnostic modalities for abdominal evaluation for trauma assessment. In our opinion sonography should replace other invasive techniques to rapidly triage blunt trauma patients with unstable vital signs and examine the peritoneal cavity as a site of major haemorrhage to expedite exploratory laparotomy. On the other hand, CT has become the imaging modality of choice in hemodynamically stable patients with multisystem blunt and penetrating trauma. New developments in the quantitative analysis of the CT images will improve our knowledge of pathophysiology, diagnostic and therapeutic management of abdominal pathologies in critically ill patients.

Multi-detector CT features of acute intestinal ischemia and their prognostic correlations

Acute intestinal ischemia is an abdominal emergency occurring in nearly 1% of patients presenting with acute abdomen. The causes can be occlusive or non occlusive. Early diagnosis is important to improve survival rates. In most cases of late or missed diagnosis, the mortality rate from intestinal infarction is very high, with a reported value ranging from 60% to 90%. Multi-detector computed tomography (MDCT) is a fundamental imaging technique that must be promptly performed in all patients with suspected bowel ischemia. Thanks to the new dedicated reconstruction program, its diagnostic potential is much improved compared to the past and currently it is superior to that of any other noninvasive technique. The increased spatial and temporal resolution, high-quality multi-planar reconstructions, maximum intensity projections, vessel probe, surface-shaded volume rending and tissue transition projections make MDCT the gold standard for the diagnosis of intestinal ischemia, with reported sensitivity, specificity, positive and negative predictive values of 64%-93%, 92%-100%, 90%-100% and 94%-98%, respectively. MDCT contributes to appropriate treatment planning and provides important prognostic information thanks to its ability to define the nature and extent of the disease. The purpose of this review is to examine the diagnostic and prognostic role of MDCT in bowel ischemia with special regard to the state of art new reconstruction software.

Mesenteric ischemia: the importance of differential diagnosis for the surgeon

Background

Intestinal ischemia is an abdominal emergency that accounts for approximately 2% of gastrointestinal illnesses. It represents a complex of diseases caused by impaired blood perfusion to the small and/or large bowel including acute arterial mesenteric ischemia (AAMI), acute venous mesenteric ischemia (AVMI), non occlusive mesenteric ischemia (NOMI), ischemia/reperfusion injury (I/R), ischemic colitis (IC). In this study different study methods (US, CT) will be correlated in the detection of mesenteric ischemia imaging findings due to various etiologies.

Methods

Basing on our institutions experience, 163 cases of mesenteric ischemia/infarction from various cases, investigated with CT and undergone surgical treatment were retrospectively evaluated, in particular trought the following findings: presence/absence of arterial/venous obstruction, bowel wall thickness and enhancement, presence/absence of spastic reflex ileus, hypotonic reflex ileus or paralitic ileus, mural and/or portal/mesenteric pneumatosis, abdominal free fluid, parenchymal ischemia/infarction (liver, kidney, spleen).

Results

To make an early diagnosis useful to ensure a correct therapeutic approach, it is very important to differentiate between occlusive (arterial, venous) and non occlusive causes (NOMI). The typical findings of each forms of mesenteric ischemia are explained in the text.

Conclusion

The radiological findings of mesenteric ischemia have different course in case of different etiology. In venous etiology the progression of damage results faster than arterial even if the symptomatology is less acute; bowel wall thickening is an early finding and easy to detect, simplifying the diagnosis. In arterial etiology the damage progression is slower than in venous ischemia, bowel wall thinning is typical but difficult to recognize so diagnosis may be hard. In the NOMI before/without reperfusion the ischemic damage is similar to AAMI with additional involvement of large bowel parenchymatous organs. In reperfusion after NOMI and after AAMI the CT and surgical findings are similar to those of AVMI, and the injured bowel results quite easy to identify. The prompt recognition of each condition is essential to ensure a successful treatment.

Intestinal Ischemia: US-CT findings correlations

Background

Intestinal ischemia is an abdominal emergency that accounts for approximately 2% of gastrointestinal illnesses. It represents a complex of diseases caused by impaired blood perfusion to the small and/or large bowel including acute arterial mesenteric ischemia (AAMI), acute venous mesenteric ischemia (AVMI), non occlusive mesenteric ischemia (NOMI), ischemia/reperfusion injury (I/R), ischemic colitis (IC). In this study different study methods (US, CT) will be correlated in the detection of mesenteric ischemia imaging findings due to various etiologies.

Methods

Basing on experience of our institutions, over 200 cases of mesenteric ischemia/infarction investigated with both US and CT were evaluated considering, in particular, the following findings: presence/absence of arterial/venous obstruction, bowel wall thickness and enhancement, presence/absence of spastic reflex ileus, hypotonic reflex ileus or paralitic ileus, mural and/or portal/mesenteric pneumatosis, abdominal free fluid, parenchymal ischemia/infarction (liver, kidney, spleen).

Results

To make an early diagnosis useful to ensure a correct therapeutic approach, it is very important to differentiate between occlusive (arterial,venous) and nonocclusive causes (NOMI). The typical findings of each forms of mesenteric ischemia are explained in the text.

Conclusion

At present, the reference diagnostic modality for intestinal ischaemia is contrast-enhanced CT. However, there are some disadvantages associated with these techniques, such as radiation exposure, potential nephrotoxicity and the risk of an allergic reaction to the contrast agents. Thus, not all patients with suspected bowel ischaemia can be subjected to these examinations. Despite its limitations, US could constitutes a good imaging method as first examination in acute settings of suspected mesenteric ischemia.

Mesenteric vascular occlusion: comparison of ancillary CT findings between arterial and venous occlusions and independent CT findings suggesting life-threatening events

OBJECTIVE

To compare the ancillary CT findings between superior mesenteric artery thromboembolism (SMAT) and superior mesenteric vein thrombosis (SMVT), and to determine the independent CT findings of life-threatening mesenteric occlusion.

MATERIALS AND METHODS

Our study was approved by the institution review board. We included 43 patients (21 SMAT and 22 SMVT between 1999 and 2008) of their median age of 60.0 years, and retrospectively analyzed their CT scans. Medical records were reviewed for demographics, management, surgical pathology diagnosis, and outcome. We compared CT findings between SMAT and SMVT groups. Multivariate analysis was conducted to determine the independent CT findings of life-threatening mesenteric occlusion.

RESULTS

Of 43 patients, 24 had life-threatening mesenteric occlusion. Death related to mesenteric occlusion was 32.6%. A thick bowel wall (p < 0.001), mesenteric edema (p < 0.001), and ascites (p = 0.009) were more frequently associated with SMVT, whereas diminished bowel enhancement (p = 0.003) and paralytic ileus (p = 0.039) were more frequent in SMAT. Diminished bowel enhancement (OR = 20; p = 0.007) and paralytic ileus (OR = 16; p = 0.033) were independent findings suggesting life-threatening mesenteric occlusion.

CONCLUSION

The ancillary CT findings occur with different frequencies in SMAT and SMVT. However, the independent findings indicating life-threatening mesenteric occlusion are diminished bowel wall enhancement and paralytic ileus.

7T μMRI of mesenteric venous ischemia in a rat model: timing of the appearance of findings

OBJECTIVES

The aim of this study is to analyze the chronological development of macroscopic, microscopic and magnetic resonance imaging (MRI) findings in a rat model of Superior Mesenteric Venous (SMV) ligation, and to evaluate the role of MRI in the diagnosis of mesenteric venous thrombosis.

METHODS

Thirty adult Sprague-Dawley rats were used and divided in two different groups that underwent a different surgical model and a different monitoring of ischemic damage. Group I underwent macroscopical and histological observation; Group II underwent 7T μMRI evaluation and histological analysis.

RESULTS

The first alterations occurred 30 min after SMV ligation and progressively worsened until the eighth hour. The morphological and MRI findings showed the same course.

CONCLUSIONS

This study provides a systematic evaluation of early anatomopathological and MRI findings following the SMV ligation. MRI allows to identify the early pathological findings of venous mesenteric ischemia and allows to correlate those to the histopathological features. Our data suggest a relevant role of MRI in the diagnostic management of mesenteric venous thrombosis, allowing to non-invasively identify and characterize the histopathologic findings. So, thanks to these skills, its future application in early diagnosis of human mesenteric venous ischemia is supposable.

Computed tomographic evaluation of mesentery: diagnostic value in acute mesenteric ischemia

OBJECTIVE

To evaluate the computed tomographic appearances of mesentery in acute mesenteric ischemia (AMI) to recognize characteristic features and their prognostic values.

METHODS

Computed tomographic examinations of 34 patients with a confirmed diagnosis of AMI were retrospectively reviewed to evaluate the number of mesenteric vessels, diameter of the superior mesenteric artery and superior mesenteric vein, mesenteric fat stranding, mesenteric vessel pneumatosis and ascites.

RESULTS

Overall, at least one of these mesenteric signs was present in all but 1 patient. In all AMI of arterial occlusive type and in 68% of nonocclusive mesenteric ischemia, the number of arterial vessels was reduced (P = 0.067). Mesenteric vessel pneumatosis and reduced number of venous vessels were significantly associated with higher mortality (P = 0.027 and P = 0.042, respectively). Reperfusion signs were associated with a reduced mortality (28.7% vs 65.5%).

CONCLUSION

Considering its characteristic features and its possible prognostic value, the evaluation of mesentery will supply additional information in the interpretation of computed tomography in AMI.

Acute mesenteric ischemia induced by ligation of porcine superior mesenteric vein: multidetector CT evaluations

RATIONALE AND OBJECTIVES

To evaluate multidetector computed tomography (MDCT) for detecting the early changes and dynamic evolution of acute mesenteric ischemia (AMI) induced by the ligation of superior mesenteric vein (SMV) in an experimental porcine model.

MATERIALS AND METHODS

Twelve pigs were randomly assigned to three experimental groups, and one control group with three pigs in each group. After laparotomy, the SMV was separated and ligated in nine pigs and separated without ligation in three controls. MDCT pre- and postcontrast with arterial, venous, and delayed phase scans, and CT angiography reconstructions of mesenteric vessels were carried out at preoperation, 6 hours, 12 hours, and 18 hours after ligation. The findings of mesenteric vessels, bowel, abdominal cavity at pre- and postoperation, and dynamic evolution were correlated with pathology.

RESULTS

AMI-induced pathological changes were identified in all nine experimental pigs. MDCT angiography clearly delineated main trunk of the SMV, peripheral major and minor tributaries up to brushy vasa recta, and the location and shape of ligations. The early ischemic findings were bowel wall thickening, mesenteric edema, ascites, and pronounced bowel enhancement. Superior mesenteric artery and its major branches appeared spasm with poor filling and delayed and prolonged visualization. SMV and its tributaries were poorly delineated with delayed opacification. We also saw thinning of bowel wall, dilatating bowel with fluid, aggravating mesenteric edema and ascites, and poor enhanced bowel over time.

CONCLUSION

MDCT detects early changes of mesenteric ischemia and its evolution after ligation of porcine SMV, and may find application in early diagnosis of human venous occlusive AMI.

Contrast-enhanced sonography in the diagnosis of acute mesenteric ischemia: case report

Acute mesenteric ischemia is a serious condition associated with high mortality. Multislice CT and magnetic resonance angiography have proved accurate in diagnosing this pathology, which requires a prompt diagnosis to start appropriate therapy. We report the case of an 87-year-old woman with acute mesenteric ischemia, in whom contrast-enhanced sonography visualized the occluded superior mesenteric artery and the infarcted portion of the intestine.

A Strange Case of Left Bowel Ischemia after Right Hernioplasty

We report the first observed case of a young man who suffered of large and unsuspected left bowel ischemia following an elective right open hernioplasty. A 54-year-old man had a 2-year history of right inguinal reducible mass and was admitted to hospital for an elective day case open inguinal hernioplasty for a direct right inguinal hernia. Apart from mild hypertension controlled with ACE inhibitor, he was medically fit and well. The patient was submitted to open tension-free mesh repair with polypropylene preshaped mesh with local infiltration anesthesia and additive sedation with midazolam. The local anesthesia and surgery were uneventful and he was discharged home on the same day as per day case protocol. He was readmitted about 12 h after discharge with a history of central and left lower abdominal pain with palpable mass, and distension and fever (38°C). After imaging and laboratory studies the patient was submitted to explorative surgery with the suspicion of left colonic ischemia. After intraoperative confirmation we performed standard left hemicolectomy. The postoperative course was uneventful; the patient was discharged in good general condition on the 7th postoperative day. Actually, the patient is in follow-up, with normal coagulation and hemochromocytometric pattern, asymptomatic for hypercholesterolemia and atrial flutter/fibrillation. Complications relating to bowel during open techniques of hernia repair are limited to two situations: the freeing of an incarcerated or strangulated segment of bowel and inadvertent laceration of large bowel in the presence of a sliding hernia. Following this strange case of colonic ischemia, a boolean Medline search (terms: hernia, complication, repair, groin, herniorrhaphy, hernioplasty, all major MESH subjects without language restriction) revealed no previous similar cases reported. However, to our knowledge, there is another trouble hypothesis: not causality but casualty. In conclusion, to our knowledge this is the first reported case of large left bowel ischemia following right open hernioplasty. We can conclude that the presence of a dolichocolon is an added risk factor for this rare and uneventful complication, but further investigations and case reports are necessary to estabilish the real causality.

Small bowel vascular disorders from arterial etiology and impaired venous drainage

Intestinal ischemia of the small bowel represents an important diagnostic question to answer in an emergency. Although some findings could be appreciated with basic imaging methods, the MDCT as a modern noninvasive imaging method could be effective in evaluating intestinal disease caused by superior mesenteric artery or vein occlusion and making a diagnosis of ischemia from low-flow states. Looking at the features of the parietal layers with knowledge of the pathologic mechanism underlying the changes from the "normality" could be helpful in making a correct, prompt, and effective diagnosis of intestinal ischemia or disease from impaired venous drainage.

Imaging of ischemic colitis

Ischemic colitis accounts for more than half of all cases of gastrointestinal ischemia and constitutes between 1 per 2000 and 3 per 1000 acute hospital admission. It typically affects elderly patients, being a frequent cause of rectal bleeding, abdominal pain, and diarrhea. This article describes the epidemiology, physiology, and pathology of this underdiagnosed condition; reviews the clinical patterns of this disease, which constitute a key diagnostic point in patients who have a thickening of the colonic wall; and describes the ultrasound (US) and CT findings, pitfalls, and differential diagnoses of ischemic colitis. The value and limitations of US and CT at the different diagnostic stages is discussed.

Imaging in intestinal ischemic disorders

Intestinal ischemia and infarction are a heterogeneous group of diseases that have as their unifying theme hypoxia of the small bowel or colon. The incidence of bowel ischemia and infarction is on the rise for several reasons: the aging of the population, the ability of intensive care units to salvage critically ill patients, and heightened clinical awareness of these disorders. Improvements in diagnostic imaging techniques have greatly contributed to the earlier diagnosis of intestinal ischemia, which can have a positive influence on patient outcomes. In this article, role of radiology in the detection, differential diagnosis, and management of patients who have intestinal ischemia and infarction is discussed.

Intramural and subserosal echogenic foci on US in large-bowel intussusceptions: prognostic indicator for reducibility?

BACKGROUND

In large-bowel intussusceptions, several US signs are known to indicate a lower likelihood of reducibility by enema. US can demonstrate echogenic dots or lines (foci) in the bowel wall, which might indicate an ischemic bowel.

OBJECTIVE

To determine the presence of echogenic intramural and subserosal foci in large-bowel intussusceptions and to evaluate the degree of correlation with reducibility.

MATERIALS AND METHODS

Between 2001 and 2008, 74 consecutive US examinations were retrospectively evaluated by two pediatric radiologists for intramural and subserosal echogenic foci, or trapped gas, in the intussusception. The degree of correlation between the sonographic findings and reducibility was evaluated.

RESULTS

Of 73 intussusceptions examined by US, 56 (76%) were reducible and 17 (23%) were not reducible. Out of 10 intussusceptions with intramural gas, 11 with subserosal gas, and 14 with intramural and subserosal gas, 8 (80%), 6 (56%), 9 (64%), respectively, were not reducible. The presence of intramural gas or subserosal gas or both predicted a lower chance of reduction, but with regard to the effect of these findings together, intramural gas was the only significant predictor.

CONCLUSION

Having intramural gas in large-bowel intussusception significantly decreases the chance of reduction.

Gastrointestinal disorders in elderly patients

Gastrointestinal disorders are common in elderly patients, and the clinical presentation, complications, and management may differ from those in younger patient. Most impairment occurs in the proximal and distal tract of the gastrointestinal system. Swallowing abnormalities with a wide span of symptoms and pelvic floor pathologies involving all the pelvic compartments are common. Acute abdomen, often from small bowel obstruction or mesenteric ischemia, can pose a diagnostic challenge, because a mild clinical presentation may hide serious visceral involvement. In this setting, the radiologist often is asked to suggest the appropriate management options and to guide the management.

Acute mesenteric ischemia after cardio-pulmonary bypass surgery

Acute mesenteric ischemia (AMI) is a highly-lethal surgical emergency. Several pathophysiologic events (arterial obstruction, venous thrombosis and diffuse vasospasm) lead to a sudden decrease in mesenteric blood flow. Ischemia/reperfusion syndrome of the intestine is responsible for systemic abnormalities, leading to multi-organ failure and death. Early diagnosis is difficult because the clinical presentation is subtle, and the biological and radiological diagnostic tools lack sensitivity and specificity. Therapeutic options vary from conservative resuscitation, medical treatment, endovascular techniques and surgical resection and revascularization. A high index of suspicion is required for diagnosis, and prompt treatment is the only hope of reducing the mortality rate. Studies are in progress to provide more accurate diagnostic tools for early diagnosis. AMI can complicate the post-operative course of patients following cardio-pulmonary bypass (CPB). Several factors contribute to the systemic hypo-perfusion state, which is the most frequent pathophysiologic event. In this particular setting, the clinical presentation of AMI can be misleading, while the laboratory and radiological diagnostic tests often produce inconclusive results. The management strategies are controversial, but early treatment is critical for saving lives. Based on the experience of our team, we consider prompt exploratory laparotomy, irrespective of the results of the diagnostic tests, is the only way to provide objective assessment and adequate treatment, leading to dramatic reduction in the mortality rate.

Acute colonic disease: How to image in emergency

The diseases affecting the large intestine represent a diagnostic problem in adult patients with acute abdomen, especially when clinical symptoms are not specific. The role of the diagnostic imaging is to help clinicians and surgeons in differential diagnosis for an efficient early and prompt therapy to perform. This review article summarizes the imaging spectrum of findings of colonic acute disease, from mechanical obstruction to inflammatory diseases and perforation, offering keys to problem solving in doubtful cases as well as discussing regarding the more indicated imaging method to use in emergency, particularly MDCT.

Inflammatory chronic disease of the colon: how to image

Inflammatory bowel disease, including Crohn's disease and UC, is a chronic disorder of the gastrointestinal tract. The inflammatory process in UC is confined to the mucosa and submucosa and it involves only the colon. In contrast, in Crohn's disease the inflammation process extends through the bowel wall layers and it can involve any part of gastrointestinal tract. Moreover, inflammatory bowel disease of the colon may be associated with complications, such as toxic megacolon, fulminant colitis, acute bleeding, fistulas and abscesses. Radiographic imaging studies are useful for the diagnosis of inflammatory bowel disease, and may be used to assess the extent and severity of disease, rule out complications, and monitor the response to therapy. The double-contrast barium study is a valuable technique for diagnosing inflammatory bowel disease colonic alterations, even in patients with early mucosal abnormalities. The earliest finding of UC is characterized by a fine granular appeareance of the colonic mucosa, usually involving the rectosigmoid junction. In chronic UC double-contrast enema may reveal marked colonic shortening with tubular narrowing of the bowel and loss of haustration. The earliest radiographics findings of Crohn's disease are represented by aphthous ulcers. As disease progresses, aphthous ulcers may enlarge and coalesce to form stellate or linear areas of ulceration. In advanced Crohn's disease, transmural ulceration may lead to the development of fissures, sinus tracts, fistulas, and abscesses. Cross sectional studies such as computed tomography, magnetic resonance imaging and sometimes ultrasound, are useful alternative tools not only in the assessment of bowel wall abnormalities, but also for the assessment of extraluminal alterations in patients with advanced disease.

Multidetector row computed tomography findings from ischemia to infarction of the large bowel

OBJECTIVE

MDCT is performed as first imaging examination for patients with acute abdomen in most Emergency Departments. Clinical suspicion of ischemic colitis and infarction is related to specific findings, however, differential diagnosis as well as the staging for a confirmed ischemic affection may be critical. The individual signs from ischemia to infarction of large bowel is a captivating topic. In this study, we report our experience of the MDCT assessment of acute colonic disease from vascular mesenteric disorders.

MATERIALS AND METHODS

We retrospectively reviewed the MDCT findings of 71 patients admitted to our attention for acute abdomen, with final proven diagnosis of colonic ischemia and/or infarction made by surgery and/or endoscopy. CT-scanning of the abdomen and pelvis was performed after i.v. contrast medium administration, using a multidetector row CT equipment. We correlated the presence of parietal disease, the evidence of mesenteric arterial or venous vessels occlusion, the parietal features as well as others findings, such as free fluid and/or air in peritoneal recess or in retroperitoneum, with the surgical and/or endoscopic findings.

RESULTS

Analysis of our data showed a segmental (84%) or complete (16%) involvement of the colon; 57 cases were related to ischemia, 14 to infarction. Inferior mesenteric vessels defect of opacification was noted in 10 cases. Various degree of wall thickening and parietal enhancement, peritoneal fluid, mural or portal-mesenteric pneumatosis were compared to evidence of mesenteric arterial or vein occlusion and to final proven diagnosis. A classification in a multi-stage grading for both decreased of arterial supply or impaired venous drainage disorders was done.

CONCLUSIONS

A grading scale from ischemia to infarction affecting the large bowel from arterial or venous mesenteric vessels origin has been not previously reported in a series at our knowledge. MDCT findings may support the clinical evaluation of patients affected by acute colon from vascular disorders. In particular, it seems to provide effective and valuable information's in differentiating etiology and stage of disease.