CT and MR imaging findings of bowel ischemia from various primary causes

Diagnosis and emergency surgical management of stercoral colitis-induced colonic ischemia: A case report and literature review

INTRODUCTION AND IMPORTANCE

Stercoral colitis is an urgent complication of fecal impaction that requires aggressive management. The rare complicated with bowel ischemia requires a high index of suspicion for early diagnosis. This case report describes the detection and management of this rare and fatal complication of stercoral colitis.

CASE PRESENTATION

An 80-year-old man presented after 3 days of obstipation. Abdominal plain radiography revealed several air-fluid levels in the colon with centralized small bowel gas. Computed tomography revealed fecal impaction and stercoral colitis without evidence of bowel ischemia.

CLINICAL DISCUSSION

Fecal impaction and stercoral colitis without evidence of bowel ischemia was suspected. Owing to the development of refractory septic shock, we performed damage control surgery. Definitive surgery with end ileostomy was follow by 48 h later. The patient was discharged home safely.

CONCLUSION

Stercoral colitis-induced ischemia is rare but potentially fatal; ischemia should be highly suspected. CT can help diagnosed of stercoral colitis but no single parameters for diagnosed of bowel ischemia. Prompt resuscitation and surgical exploration with damage control surgery are recommended.

The optimal surgery timing after stenting in colorectal cancer patients with malignant obstruction: additionally compared with emergency surgery

BACKGROUND

This study aimed to determine short-term and long-term outcomes according to time intervals after stenting and compared them with those of emergency surgery (ES) in colorectal cancer (CRC) with malignant obstruction.

METHODS

CRC with malignant obstructions was reviewed retrospectively between January 2008 and July 2018. Of a total of 539 patients who visited the emergency room and underwent ES, 133 were enrolled in the ES group. Of a total of 567 patients who initially received stenting and subsequently underwent elective surgery, 220 were enrolled in the SEMS group. The interval between SEMS placement and elective surgery was classified as < 11 days, 11-17 days, and > 17 days.

RESULTS

For those who received SEMS (n = 220), those with a time interval of 11-17 days (n = 97) had fewer hospital days than those with a time interval of < 11 days (n = 68) (8 days vs. 15 days) and less stoma formation than those with a time interval of > 17 days (n = 55) (1.0% vs. 14.6%). Multivariable analysis revealed a decreased risk of death for the group with a time interval of 11-17 days (20.6%) compared to the ES group (31.6%) (hazard ratio: 0.48; 95% confidence interval: 0.24-0.97). Disease-free survival was comparable between the SEMS and ES groups regardless of the time interval (log-rank p = 0.52).

CONCLUSIONS

The time interval of 11-17 days after stenting to elective surgery appeared to be associated with the most favorable outcomes.

Multidetector CT Imaging Biomarkers as Predictors of Prognosis in Shock: Updates and Future Directions

A severe mismatch between the supply and demand of oxygen is the common sequela of all types of shock, which present a mortality of up to 80%. Various organs play a protective role in shock and contribute to whole-body homeostasis. The ever-increasing number of multidetector CT examinations in severely ill and sometimes unstable patients leads to more frequently encountered findings leading to imminent death, together called "hypovolemic shock complex". Features on CT include dense opacification of the right heart and major systemic veins, venous layering of contrast material and blood, densely opacified parenchyma in the right hepatic lobe, decreased enhancement of the abdominal organ, a dense pulmonary artery, contrast pooling in dependent lungs, and contrast stasis in pulmonary veins. These findings are biomarkers and prognostic indicators of paramount importance which stratify risk and improve patient outcomes. In this review, we illustrate the various CT patterns in shock and review the spectrum and prognostic significance of thoraco-abdominal vascular and visceral alarming signs of impending death with the intention of increasing awareness among radiologists and radiographers to prepare for immediate resuscitation when required.

Imaging of Bowel Ischemia: An Update, From the AJR Special Series on Emergency Radiology

Acute mesenteric ischemia is a life-threatening condition that results from abrupt reduction in or cessation of blood flow to the bowel. Characterized by nonspecific abdominal symptoms, mesenteric ischemia is infrequently encountered and commonly misdiagnosed, with potentially catastrophic consequences. Prompt clinical diagnosis and early implementation of therapeutic interventions are critical to improving patient outcomes. Because cross-sectional imaging plays a key role in the diagnosis of mesenteric ischemia, radiologists must be familiar with the varied imaging manifestations of intestinal ischemia. Thus, the objectives of this article are to review the various types and common causes of mesenteric ischemia and to describe its spectrum of multimodality imaging findings, with special attention to novel imaging techniques and emerging diagnoses.

Ultrasound during the COVID-19 Pandemic: A Global Approach

SARS-CoV-2 (severe acute respiratory syndrome Coronavirus-2) rapidly spread worldwide as COVID-19 (Coronavirus disease 2019), causing a costly and deadly pandemic. Different pulmonary manifestations represent this syndrome's most common clinical manifestations, together with the cardiovascular complications frequently observed in these patients. Ultrasound (US) evaluations of the lungs, heart, and lower limbs may be helpful in the diagnosis, follow-up, and prognosis of patients with COVID-19. Moreover, POCUS (point-of-care ultrasound) protocols are particularly useful for patients admitted to intensive care units. The present review aimed to highlight the clinical conditions during the SARS-CoV-2 pandemic in which the US represents a crucial diagnostic tool.

Unsupervised and quantitative intestinal ischemia detection using conditional adversarial network in multimodal optical imaging

Purpose

Intraoperative evaluation of bowel perfusion is currently dependent upon subjective assessment. Thus, quantitative and objective methods of bowel viability in intestinal anastomosis are scarce. To address this clinical need, a conditional adversarial network is used to analyze the data from laser speckle contrast imaging (LSCI) paired with a visible-light camera to identify abnormal tissue perfusion regions.

Approach

Our vision platform was based on a dual-modality bench-top imaging system with red-green-blue (RGB) and dye-free LSCI channels. Swine model studies were conducted to collect data on bowel mesenteric vascular structures with normal/abnormal microvascular perfusion to construct the control or experimental group. Subsequently, a deep-learning model based on a conditional generative adversarial network (cGAN) was utilized to perform dual-modality image alignment and learn the distribution of normal datasets for training. Thereafter, abnormal datasets were fed into the predictive model for testing. Ischemic bowel regions could be detected by monitoring the erroneous reconstruction from the latent space. The main advantage is that it is unsupervised and does not require subjective manual annotations. Compared with the conventional qualitative LSCI technique, it provides well-defined segmentation results for different levels of ischemia.

Results

We demonstrated that our model could accurately segment the ischemic intestine images, with a Dice coefficient and accuracy of 90.77% and 93.06%, respectively, in 2560 RGB/LSCI image pairs. The ground truth was labeled by multiple and independent estimations, combining the surgeons' annotations with fastest gradient descent in suspicious areas of vascular images. The total processing time was 0.05 s for an image size of 256 × 256 .

Conclusions

The proposed cGAN can provide pixel-wise and dye-free quantitative analysis of intestinal perfusion, which is an ideal supplement to the traditional LSCI technique. It has potential to help surgeons increase the accuracy of intraoperative diagnosis and improve clinical outcomes of mesenteric ischemia and other gastrointestinal surgeries.

Interpretation discrepancies of abdominal imaging by on-call radiology residents: Evaluation of risk factors

The aim of this study was to determine the rate, important findings, and risk factors related to discrepancies between on-call residents’ and attending radiologists’ interpretations of abdominal examinations. We identified 1132 eligible patients with abdominal radiology findings that were preliminary interpreted by on-call residents between February 2016 and September 2019. The preliminary interpretations were compared with the final interpretations by abdominal attending radiologists, including clinical data. The preliminary interpretations were analyzed by three radiologists in consensus, who categorized the reports according to organs, important findings (i.e., active bleeding, bowel obstruction, organ ischemia or infarction, and organ rupture), clinical outcomes, and discrepancies with respect to final interpretations. Multiple logistic regression analysis was used to evaluate the risk factors for important discrepant findings. Of 1132 patients, the bowel (n = 567, 50.1%) was the most common organ interpreted by on-call residents, followed by gallbladder/bile duct/pancreas (n = 139, 12.3%) and liver (n = 116, 10.2%). Of 1132, 359 patients (31.7%) had disease with 379 important findings: active bleeding (n = 222), organ rupture (n = 77), bowel obstruction (n = 52), bowel ischemia (n = 24), and organ infarction (n = 4). Sixty-four patients (5.6%) showed discrepancies, and 30 (2.6%) showed 32 important discrepant findings comprising 14 active bleeding, 10 bowel obstructions, 6 organ ruptures, and 2 cases of bowel ischemia. Of the 64 discrepant patients, 33 underwent delayed surgery (n = 18, 28.1%) or interventional treatment (n = 15, 23.4%). In multivariable analysis, bowel obstruction (adjusted odds ratio, 2.52; p = 0.049) was an independent risk factor for determining discrepancy between preliminary and final interpretations. The rate of overall and important discrepancies between on-call residents’ and final interpretations was low. However, given that the bowel was the most frequently interpreted organ, bowel obstruction was identified as a risk factor for discrepant interpretations. The identified risk factor and findings may be useful for residents to minimize discrepancies.

The Delta SARS-CoV-2 Variant of Concern Induces Distinct Pathogenic Patterns of Respiratory Disease in K18-hACE2 Transgenic Mice Compared to the Ancestral Strain from Wuhan

Compared to the original ancestral strain of SARS-CoV-2, the Delta variant of concern has shown increased transmissibility and resistance toward COVID-19 vaccines and therapies. However, the pathogenesis of the disease associated with Delta is still not clear. In this study, using K18-hACE2 transgenic mice, we assessed the pathogenicity of the Delta variant by characterizing the immune response following infection. We found that Delta induced the same clinical disease manifestations as the ancestral SARS-CoV-2, but with significant dissemination to multiple tissues, such as brain, intestine, and kidney. Histopathological analysis showed that tissue pathology and cell infiltration in the lungs of Delta-infected mice were the same as in mice infected with the ancestral SARS-CoV-2. Delta infection caused perivascular inflammation in the brain and intestinal wall thinning in K18-hACE2 transgenic mice. Increased cell infiltration in the kidney was observed in both ancestral strain- and Delta-infected mice, with no clear visible tissue damage identified in either group. Interestingly, compared with mice infected with the ancestral strain, the numbers of CD45⁺ cells, T cells, B cells, inflammatory monocytes, and dendritic cells were all significantly lower in the lungs of the Delta-infected mice, although there was no significant difference in the levels of proinflammatory cytokines between the two groups. Our results showed distinct immune response patterns in the lungs of K18-hACE2 mice infected with either the ancestral SARS-CoV-2 or Delta variant of concern, which may help to guide therapeutic interventions for emerging SARS-CoV-2 variants. IMPORTANCE SARS-CoV-2 variants, with the threat of increased transmissibility, infectivity, and immune escape, continue to emerge as the COVID-19 pandemic progresses. Detailing the pathogenesis of disease caused by SARS-CoV-2 variants, such as Delta, is essential to better understand the clinical threat caused by emerging variants and associated disease. This study, using the K18-hACE2 mouse model of severe COVID-19, provides essential observation and analysis on the pathogenicity and immune response of Delta infection. These observations shed light on the changing disease profile associated with emerging SARS-CoV-2 variants and have potential to guide COVID-19 treatment strategies.

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.

Systemic Emergencies in COVID-19 Patient: A Pictorial Review

Since the first report of the outbreak in Wuhan, China in December 2019, as of 1 September 2021, the World Health Organization has confirmed more than 239 million cases of the novel coronavirus (SARS-CoV-2) infectious disease named coronavirus disease 2019 (COVID-19), with more than 4.5 million deaths. Although SARS-CoV-2 mainly involves the respiratory tract, it is considered to be a systemic disease. Imaging plays a pivotal role in the diagnosis of all manifestations of COVID-19 disease, as well as its related complications. The figure of the radiologist is fundamental in the management and treatment of the patient. The authors try to provide a systematic approach based on an imaging review of major multi-organ manifestations of this infection.

Time limit to rescue intestine with viability at risk caused by blood flow disruption in patients presenting with acute abdomen

Purpose

Early management is crucial for acute intestinal blood flow disorders; however, no published study has identified criteria for the time limit for blood flow resumption. This study specifically examines the time factors for avoiding intestinal resection.

Methods

The subjects of this retrospective cohort study were 125 consecutive patients who underwent emergency surgery for a confirmed diagnosis of intestinal strangulation (n = 86), incarceration (n = 27), or volvulus (n = 12), between January 2015 and March 2021. Intestinal resection was performed when intestinal irreversible changes had occurred even after ischemia was relieved surgically. We analyzed the relationship between the time from computed tomography (CT) imaging to the start of surgery (C-S time) and intestinal resection using the Kaplan–Meier method and calculated the estimated intestinal rescue rate. Patient background factors affecting intestinal resection were also examined.

Results

The time limit for achieving 80% intestinal rescue rate was 200 min in C-S time, and when this exceeded 300 min, the intestinal rescue rate dropped to less than 50%. Multivariate analysis identified the APACHE II score as a significant influencing factor.

Conclusion

A rapid transition from early diagnosis to early surgery is critical for patients with acute abdomen originating from intestinal blood flow disorders. The times from presentation at the hospital to surgery should be reduced further, especially for severe cases.

Portal Vein Thrombosis in Cirrhosis

Patients with cirrhosis of the liver are at high risk of developing portal vein thrombosis (PVT), which has a complex, multifactorial cause. The condition may present with a myriad of symptoms and can occasionally cause severe complications. Contrast-enhanced computed tomography (CT) is the gold standard for the diagnosis of PVT. There are uncertainties regarding the effect on PVT and its treatment outcome in patients with cirrhosis. The main challenge for managing PVT in cirrhosis is analyzing the risk of hemorrhage compared to the risk of thrombus extension leading to complications. All current knowledge regarding non-tumor PVT in cirrhosis, including epidemiology, risk factors, classification, clinical presentation, diagnosis, impact on natural history, and treatment, is discussed in the present article.

Radiological and clinical findings of idiopathic myointimal hyperplasia of mesenteric veins: Case report

INTRODUCTION

Idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) is an uncommon cause of ischemic bowel disease resulting from the proliferation of smooth muscles in the venous intima. Delayed diagnosis could only be made following the surgical resection due to lack of imaging data, which may lead to bowel severe bleeding, perforation, necrosis, infection, or shock. In previous reports, few cases have provided the detailed pre-operative radiological characteristics of IMHMV. Herein, we are the first to provide the complete clinical course and comprehensive pre-operative radiological data of a 21-year-old female diagnosed with IMHMV.

PATIENT CONCERNS

A 21-year-old female was admitted to our hospital with bloody diarrhea and abdominal pain. Physical examination revealed tenderness localized to the left lower abdomen. The patient had no prior history of similar symptoms. A computed tomography scan was performed and showed diffuse wall thickening from the rectum to sigmoid colon with poor mural enhancement, multiple ulcers, fat stranding, and free fluid. The arterial phase images demonstrated many tortuous pericolic arteries and submucosal pseudoaneurysm.

INTERVENTION

Conservative treatment including empirical antibiotics, Mesalazine, and methylprednisolone sodium succinate were administrated to relief the symptoms. However, the diarrhea and abdominal pain worsened. An emergency surgery was arranged and total proctocolectomy with ileal pouchanal anastomosis with ileostomy was performed.

DIAGNOSIS

Macroscopic and histopathological examinations of the excised specimen showed ischemic colitis. Elastica van Gieson staining revealed extensive myointimal hyperplasia and confirmed the diagnosis of IMHMV.

OUTCOMES

During the 2-year follow-up period, no additional medical management was needed. The patient was well and surveillance colonoscopy showed normal colon and anastomosis.

CONCLUSION

Pre-operative computed tomography with imaging features including pronounced continuous concentric thickening colonic wall with poor enhancement and enlarged tortuous pericolic arteries could specifically facilitate the speedy diagnosis of IMHMV.

Imaging of abdominal complications of COVID-19 infection

Coronavirus disease 2019 (COVID-19) is a respiratory syndrome caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) first described in Wuhan, Hubei Province, China in the last months of 2019 and then declared as a pandemic. Typical symptoms are represented by fever, cough, dyspnea and fatigue, but SARS-CoV-2 infection can also cause gastrointestinal symptoms (vomiting, diarrhoea, abdominal pain, loss of appetite) or be totally asymptomatic. As reported in literature, many patients with COVID-19 pneumonia had a secondary abdominal involvement (bowel, pancreas, gallbladder, spleen, liver, kidneys), confirmed by laboratory tests and also by radiological features. Usually the diagnosis of COVID-19 is suspected and then confirmed by real-time reverse-transcription-polymerase chain reaction (RT-PCR), after the examination of the lung bases of patients, admitted to the emergency department with abdominal symptoms and signs, who underwent abdominal-CT. The aim of this review is to describe the typical and atypical abdominal imaging findings in patients with SARS-CoV-2 infection reported since now in literature.

CT manifestations of small bowel ischemia due to impaired venous drainage-with a correlation of pathologic findings

Acute abdominal pain may result from a wide variety of medical and surgical diseases. One of these diseases is small bowel ischemia, which may result in a catastrophic outcome if not recognized and treated promptly. Computed tomography (CT) by its faster image acquisition, thinner collimation, high resolution, and multiplanar reformatted images has become the most important imaging modality in evaluating the acute abdominal conditions. In this article, the author presents a description of the histology of the small bowel, pathophysiology of small bowel change, and a correlation of the pathologic and CT findings of the small bowel injuries due to impaired venous drainage. A convincing correlation of the microscopic mucosal condition with the enhancement pattern of the thickened small bowel wall on CT is useful in definitely describing the mucosal viability.

Evaluation of Bowel and Mesentery in Abdominal Trauma

Since the advent of multidetecter computed tomography (CT), radiologist sensitivity in detection of traumatic bowel and mesenteric abnormalities has significantly improved. Although several CT signs have been described to identify intestinal injury, accurate interpretation of these findings can remain challenging. Early detection of bowel and mesenteric injury is important as it alters patient management, disposition, and follow-up. This article reviews the common imaging findings of traumatic small bowel and mesenteric injury.

Imaging of acute abdomen in cancer patients

The pattern of disease causing acute abdominal pain has changed over last few decades, some of this has been attributed to intraabdominal cancers. The most common acute abdominal complaints in cancer patients are related to the gastrointestinal system. Abdominal emergencies in cancer patients can result from the underlying malignancy itself, cancer therapy and/or result from the standard pathologies causing acute abdomen in otherwise healthy population. Therapy-related or disease-related immunosuppression or high dose analgesics often blunt many of the findings which are usually expected in non-cancer general population. This complicates the clinical picture rendering the clinical exam less reliable in many cancer patients, and resulting in different pathologies which clinicians and the radiologists should remain aware of. This article focuses on imaging illustrations with differential diagnosis for various emergency scenarios related to acute abdomen specifically in oncologic settings.

Nationwide estimate of emergency department visits in the United States related to caustic ingestion

INTRODUCTION

Caustic ingestion, whether intentional or unintentional, may result in significant morbidity. Our aim was to provide an estimate of the incidence and outcomes of caustic ingestion among emergency department (ED) visits across the United States.

METHODS

The Nationwide Emergency Department Sample (NEDS) is part of the family of databases developed for the Healthcare Cost and Utilization Project. We analyzed NEDS for the period 2010-2014. Adults (≥18 years of age) with a diagnosis of caustic ingestion were identified by ICD-9 codes. The weighted frequencies and proportions of caustic ingestion-related ED visits by demographic characteristics and disposition status were examined. A weighted multivariable logistic regression model was performed to examine factors associated with inpatient admission for caustic ingestion-related visits.

RESULTS

From 2010 to 2014, there were 40,844 weighted adult ED visits related to caustic ingestion among 533.8 million visits (7.65/100,000, 95% CI 7.58/100,000-7.73/100,000), resulting in over $47 million in annual cost. Among ED visits related to caustic ingestion, 28% had comorbid mental and substance use disorders. Local and systemic complications were rare. There was significant regional, gender, and insurance variability in the decision as to perform endoscopy. Males, insured patients, patients domiciled in the Southeast region of the United States, and patients with mental or substance use disorders had significantly higher percentages of receiving endoscopic procedures. Overall, 6,664 (16.27%) visits resulted in admission to the same hospital and 1,063 (2.60%) visits resulted in transfer to another hospital or facility. The risk factors for admission were increasing in age, male gender, local or systemic complications related to caustic ingestion, and comorbid mental and substance use disorders. A total of 161 (0.39%) patients died related to caustic ingestion.

CONCLUSION

Our results from NEDS provide national estimates on the incidence of caustic ingestions involving adults seen in US EDs. Further studies are needed to examine the standard management of caustic ingestion and investigate the factors causing variability of esophagogastroduodenoscopy performance and caustic ingestion care.

Gastrointestinal perforation: clinical and MDCT clues for identification of aetiology

Gastrointestinal tract (GIT) perforation is a common medical emergency associated with considerable mortality, ranging from 30 to 50%. Clinical presentation varies: oesophageal perforations can present with acute chest pain, odynophagia and vomiting, gastroduodenal perforations with acute severe abdominal pain, while colonic perforations tend to follow a slower progression course with secondary bacterial peritonitis or localised abscesses. A subset of patients may present with delayed symptoms, abscess mimicking an abdominal mass, or with sepsis.

Direct multidetector computed tomography (MDCT) findings support the diagnosis and localise the perforation site while ancillary findings may suggest underlying conditions that need further investigation following primary repair of ruptured bowel. MDCT findings include extraluminal gas, visible bowel wall discontinuity, extraluminal contrast, bowel wall thickening, abnormal mural enhancement, localised fat stranding and/or free fluid, as well as localised phlegmon or abscess in contained perforations.

The purpose of this article is to review the spectrum of MDCT findings encountered in GIT perforation and emphasise the MDCT and clinical clues suggestive of the underlying aetiology and localisation of perforation site.

CT diagnosis of non-traumatic gastrointestinal perforation: an emphasis on the causes

Gastrointestinal tract (GI) perforations can occur due to various causes such as trauma, iatrogenic factor, infectious condition, peptic ulcer, inflammatory disease, or a neoplasm. Because GI perforations represent an emergency and life-threatening condition, prompt diagnosis and surgical treatment are required in most cases. However, according to the underlying causes of GI perforations, additional treatment strategies may be needed. Adjuvant chemotherapy or immunotherapy may be required in various GI neoplasms such as adenocarcinoma, lymphoma or gastrointestinal stromal tumor. Inflammatory bowel disease is a chronic disease repeating cycle of intermittent, thus appropriate medical treatment and periodic follow-up are also required. Moreover, vascular intervention may have a role in some cases of mesenteric ischemia associated with mesenteric artery occlusion. Recently, computed tomography (CT) has been the first choice for patients with suspected GI perforations, because CT plays an important role in the accurate assessment of the perforation site, the pathology causing the perforation and the ensuing complications. This review will illustrate characteristic CT findings that differentiate underlying pathologies causing GI perforations to help clinicians decision-making regarding an optimal treatment plan.

Duodenal emergencies: utility of multidetector CT with 2D multiplanar reconstructions for challenging but critical diagnoses

Duodenal pathology is an infrequent cause of acute abdominal pain for which patients present to the emergency department. Critical pathology on multidetector CT (MDCT) may be overlooked if the radiologist does not carefully evaluate the duodenum as part of the search pattern. Optimal MDCT protocols include intravenous contrast with multiplanar reconstructions (MPRs). A variety of etiologies ranging from infection to malignancy can involve the duodenum, for which interrogation with MPRs is most helpful given the anatomy and complex relationship with surrounding structures. The purpose of this review article is to highlight the importance of CT acquisition with multiplanar reconstructions and review the spectrum of emergent duodenal pathology, with the goal of ensuring accurate and timely diagnosis to best guide patient management.

Advanced urothelial cancer: a radiology update

The recent genomic characterization of urothelial carcinoma by the Cancer Genome Atlas Project, made possible by the introduction of high throughput, reduced cost, and sequence analysis, has shed new insights on the biology of advanced disease. In addition, studies on imaging of advanced urothelial carcinoma have widened the knowledge on disease presentation and on pattern of metastatic spread and their correlation with the underlying biology of urothelial carcinoma. The wide range of treatments for advanced urothelial cancer, including combined chemotherapy regimens and immune checkpoint inhibitors, each result in treatment class-specific patterns of response and adverse events. Results of studies point to the need for a reliable biomarker, perhaps with imaging, that predicts prognosis and treatment response to systemic treatment, and can be used to select the most effective treatment while minimizing toxicity. This review of advanced urothelial cancer introduces the latest advances in genetic profiling, the current role of imaging, the radiographic appearance of treatment response and their toxicities, and details potential future areas of imaging research.

Mesenteric ischemia: what the radiologist needs to know

Acute mesenteric ischemia (AMI) is a life-threatening condition that often presents with abdominal pain. Early diagnosis with contrast-enhanced computed tomography and revascularization can reduce the overall mortality in AMI. This article reviews practical etiological classification, pathophysiology of imaging manifestations and common pitfalls in intestinal ischemia.

MR enterography: what is next after Crohn's disease?

Within the gastrointestinal system, the small bowel represents the most difficult site to approach with imaging modalities. During the last decades, magnetic resonance enterography has reached an increasing interest, up to be considered an essential part in the diagnostic framework of Crohn's disease patients. Nevertheless, the distention of the intestinal loops provided by the administration of oral contrast medium, the possibility of a dynamic evaluation, and the lack of radiation exposure are huge advantages that can be exploited for the assessment of other clinical conditions affecting the small bowel. Physicians and radiologists should be aware of the possibilities offered by this technique, looking at it as a trustful alternative to the well-worn radiological examinations. In this respect, the purpose of this work is to show some uncommon clinical conditions that can be assessed with magnetic resonance enterography and that fall within the various differential diagnosis of the intestinal disorders.

Acute mesenteric ischaemia: a pictorial review

Abstract

Acute mesenteric ischaemia (AMI) is an uncommon cause of acute hospital admission with high mortality rates (50–90%) that requires early diagnosis and treatment. With the increase in average life expectancy, AMI represents one of the most threatening abdominal conditions in elderly patients. Untreated, AMI will cause mesenteric infarction, intestinal necrosis, an overwhelming inflammatory response and death. Early intervention can reverse this process leading to a full recovery, but the diagnosis of AMI is difficult. The failure to recognise AMI before intestinal necrosis has developed is responsible for the high mortality of the disease. Unfortunately, common CT findings in bowel ischaemia are not specific. Therefore, it is often a combination of nonspecific clinical, laboratory and radiological findings that helps most in the correct interpretation of CT findings. The purpose of this article is to provide an overview of the anatomy, physiology of mesenteric perfusion and discussions of causes, pathogenesis and CT findings in various types of acute bowel ischaemia. Familiarity with various imaging features of mesenteric injury is essential to make a timely diagnosis that will lead to improved patient outcomes.

Teaching Points

• AMI is a potentially life-threatening disorder whose prognosis depends on early recognition, accurate diagnosis and timely intervention.

• Arterial inflow occlusion due to thrombosis or embolisation is the most common cause of AMI.

• Four aetiological types of AMI have been associated with different characteristics and risk factors (EAMI, TAMI, VAMI and NOMI).

• Physical examination and laboratory findings are not sensitive or specific for diagnosing AMI; therefore, MDCT is still the first-line imaging method in suspected AMI.

• Although a number of scoring systems for prognosis have been proposed, these have not been validated in large-scale studies.

The role of multislice computed tomography (MSCT) angiography in the diagnosis and therapy of non-occlusive mesenteric ischemia (NOMI): Could MSCT replace DSA in diagnosis?

Objectives

Evaluation of multislice-CT (MSCT) during diagnosis and therapeutic decision-making in patients with suspected non-occlusive mesenteric ischemia (NOMI).

Methods

Retrospective, institutional review board-approved study of 30 patients (20 men, 10 women, mean age 64.6±14.2 years, range 24–87 years) undergoing biphasic abdominal MSCT followed by digital subtraction angiography (DSA) due to suspected NOMI. MSCT and DSA were qualitatively and quantitatively evaluated independently by two radiologists with respect to the possible diagnosis of NOMI. MSCT analysis included quantitative measurements, qualitative evaluation of contrast enhancement and assessment of secondary findings (bowel wall thickening, hypo-enhancement, intestinal pneumatosis). MSCT diagnosis and secondary findings were compared against DSA diagnosis.

Results

NOMI was diagnosed in a total of n = 28 patients. No differences were found when comparing the R1-rated MSCT diagnosis (p = 0.09) to the “gold standard”, while MSCT diagnosis was slightly inferior with R2 (p = 0.02). With R1, vessel-associated parameters revealed the best correlation, i.e. qualitative vessel width (r = -0.39;p = 0.03) and vessel contrast (r = 0.45;p = 0.01). Moderate correlations were found for quantitative vessel diameters in the middle segments (r = -0.48,p = 0.01), increasing to almost high correlations in the distal (r = -0.66;p<0.00001) superior mesenteric artery (SMA) segments. No significant correlation was apparent from secondary findings.

Conclusions

MSCT is an appropriate non-invasive method for diagnosing NOMI and leads to adequate and immediate therapeutic stratification.

Transvaginal Management of Vaginal Cuff Dehiscence with Bowel Evisceration following Delayed Diagnosis

One of the most serious complications that can arise from hysterectomy is vaginal cuff dehiscence with subsequent bowel evisceration. Treatment via vaginal approach has been utilized in early cases of vaginal cuff dehiscence where the need for bowel resection is less likely. Our case examines the treatment of vaginal cuff dehiscence through a vaginal approach approximately 36 hours after apparent vaginal dehiscence with subsequent bowel evisceration. In this case, we chose a vaginal approach even in the setting of possible bowel obstruction and a significant leukocytosis. We utilized CT scan findings to help guide our surgical approach. Although the subjective appearance of the bowel protruding through the vaginal cuff was reassuring, this played little role in guiding our decision with regard to surgical approach. Vaginal cuff dehiscence with evisceration can be managed successfully via a vaginal approach even with prolonged exposure of the bowel to vaginal flora. CT scan should be utilized to evaluate bowel integrity when considering a vaginal dehiscence repair. A high index of suspicion is warranted as these cases can present up to many years after hysterectomy.

Conservative Management of Spontaneous Isolated Dissection of the Superior Mesenteric Artery

Purpose

We report the clinical outcomes of patients with spontaneous isolated dissection of the superior mesenteric artery (SIDSMA) who were treated conservatively.

Materials and Methods

A retrospective review was performed in 14 patients from 2006 to 2016 with SIDSMA. Their clinical features and computed tomographic angiography (CTA) characteristics, treatment methods, and clinical outcomes were analyzed. The mean age was 53.6 (range, 41–73) years, and the mean follow-up duration was 20.6 (range, 1–54) months. Conservative management was the primary treatment if no bowel ischemia or arterial rupture was noted.

Results

The mean initial abdominal visual analog pain score was 7 (range, 5–9) in seven patients. The mean total duration of abdominal pain was 10.2 days (range, 2–42 days) in 10 patients. The mean percentage stenosis of the dissected SMA at the initial presentation was 78.8% in 14 patients. Complete obstruction of the SMA at the initial presentation was evident in 4 of the 14 patients (28.6%). Conservative management was successful in all 14 patients. None of the 14 patients developed bowel ischemia or an infarction. Abdominal pain did not recur in any patient during follow-up (mean, 20.6 months; range, 1–54 months).

Conclusion

Conservative management was successful for all SIDSMA patients, even those with severe compression of the true lumen or complete obstruction of the dissected SMA.

Caustic ingestion

Corrosive ingestion is a rare but potentially devastating event and, despite the availability of effective preventive public health strategies, injuries continue to occur. Most clinicians have limited personal experience and rely on guidelines; however, uncertainty persists about best clinical practice. Ingestions range from mild cases with no injury to severe cases with full thickness necrosis of the oesophagus and stomach. CT scan is superior to traditional endoscopy for stratification of patients to emergency resection or observation. Oesophageal stricture is a common consequence of ingestion and newer stents show some promise; however, the place of endoscopic stenting for corrosive strictures is yet to be defined. We summarise the evidence to provide a plan for managing these potentially life-threatening injuries and discuss the areas where further research is required to improve outcomes.

Conservative Management of Isolated Superior Mesenteric Artery and Celiac Trunk Dissection: A Case Report and Literature Review

Isolated arterial dissection without aortic pathology has been rarely reported in mesenteric vessels. The natural history and appropriate treatment for this disease is uncertain because of the scarcity of literature which limits the data available to the clinician, resulting in management challenges. Herein, we report a rare case of a 42-year-old Tunisian man with spontaneous dissection and aneurysmal dilatation of the Celiac Artery (CA) and the Superior Mesenteric Artery (SMA) with partial thrombosis. This case was successfully managed conservatively with heparin infusion and blood pressure control and the patient remained symptom free at 15 months follow up. This case demonstrates that conservative management may be warranted in non-complicated isolated visceral arterial dissection.

Endoluminal contrast for abdomen and pelvis magnetic resonance imaging

Magnetic resonance (MR) imaging of the abdomen and pelvis can be limited for assessment of different conditions when imaging inadequately distended hollow organs. Endoluminal contrast agents may provide improved anatomic definition and detection of subtle pathology in such scenarios. The available routes of administration for endoluminal contrast agents include oral, endorectal, endovaginal, intravesicular, and through non-physiologic accesses. Appropriate use of endoluminal contrast agents requires a thorough understanding of the clinical indications, available contrast agents, patient preparation, and interaction of the contrast agent with the desired MR imaging protocol. For example, biphasic oral enteric contrast agents are preferred in MR enterography as their signal properties on T1- and T2-weighted imaging allow for evaluation of both intraluminal and bowel wall pathology. In specific situations such as with MR enterography, MR defecography, and accurate local staging of certain pelvic tumors, the use of an endoluminal contrast agent is imperative in providing adequate diagnostic imaging. In other clinical scenarios, the use of an endoluminal contrast agent may serve as an indispensable problem-solving tool.

Comparison of Ischemic and Nonischemic Bowel Segments in Patients With Mesenteric Ischemia: Multidetector Row Computed Tomography Findings and Measurement of Bowel Wall Attenuation Changes

OBJECTIVE

To describe multidetector row computed tomography (MDCT) findings and to compare the enhancing ratio of ischemic and nonischemic bowel wall segments in patients with mesenteric ischemia.

PATIENTS AND METHODS

We performed a retrospective review of 69 patients with pathologically proven mesenteric ischemia who underwent a preoperative MDCT evaluation from January 1, 2010, through December 31, 2014. Two reviewers performed quantitative MDCT measurements of the bowel wall attenuation of the ischemic and nonischemic bowel segments on the unenhanced phase, arterial phase, and portal venous phase. Receiver operating characteristic curves for the enhancing ratios on the arterial phase and portal venous phase (ERv) were calculated to discriminate the 2 segments. A concordance correlation coefficient was used to assess interobserver variability.

RESULTS

The most common origin of ischemia was the mesenteric artery (45 of the 69 patients [65.2%]), but only 5 patients (7.2%) had evidence of arterial thrombus on MDCT. The quantitative MDCT measurements indicated that the ischemic bowel segments had significantly less bowel wall attenuation than the nonischemic bowel segments on the arterial phase (28.58±9.28 vs 58.97±12.50; P<.001) and the portal venous phase (33.93±11.16 vs 76.25±13.56; P<.001). The enhancing ratio on the arterial phase (cutoff, 0.32 or less; sensitivity, 89.9%; specificity, 98.6%) and the ERv (cutoff, 0.81 or less; sensitivity, 95.7%; specificity, 98.6%) predicted bowel ischemia. The most common MDCT findings in ischemic bowel were thickened bowel wall in 59 patients (85.5%), mesenteric fatty stranding in 57 (82.6%), and decreased bowel wall enhancement in 56 (81.2%). All quantitative measurements reached moderate to substantial agreement (0.399-0.601).

CONCLUSION

Without oral contrast administration and at a constant 120-peak kilovolt setting, MDCT findings of decreased enhancement of the thickened bowel wall together with a low ERv value predicted the presence of an ischemic bowel segment.

From esophagus to rectum: a comprehensive review of alimentary tract perforations at computed tomography

Gastrointestinal (GI) tract perforation is a life-threatening condition that can occur at any site along the alimentary tract. Early perforation detection and intervention significantly improves patient outcome. With a high sensitivity for pneumoperitoneum, computed tomography (CT) is widely accepted as the diagnostic modality of choice when a perforated hollow viscus is suspected. While confirming the presence of a perforation is critical, clinical management and surgical technique also depend on localizing the perforation site. CT is accurate in detecting the site of perforation, with segmental bowel wall thickening, focal bowel wall defect, or bubbles of extraluminal gas concentrated in close proximity to the bowel wall shown to be the most specific findings. In this article, we will present the causes for perforation at each site throughout the GI tract and review the patterns that can lead to prospective diagnosis and perforation site localization utilizing CT images of surgically proven cases.

Hollow organ abdominal ischemia, part II: clinical features, etiology, imaging findings and management

Acute hollow organ ischemia commonly presents with acute pain prompting radiologic evaluation and almost always requires urgent treatment. Despite different risk factors and anatomic differences, ischemia is commonly due to low flow states but can also be due to arterial and venous occlusion. Radiologic diagnosis is critical as many present with nonspecific symptoms. Contrast-enhanced computed tomography (CT) is the modality of choice. Magnetic resonance imaging (MRI) is preferred in suspected appendicitis in pregnant patients and is superior in biliary necrosis. This article provides a pictorial review of the CT/MRI features of hollow abdominal organ ischemia while highlighting key clinical features, pathogenesis, and management.

Radiological Evaluation of Bowel Ischemia

Intestinal ischemia, which refers to insufficient blood flow to the bowel, is a potentially catastrophic entity that may require emergent intervention or surgery in the acute setting. Although the clinical signs and symptoms of intestinal ischemia are nonspecific, computed tomography (CT) findings can be highly suggestive in the correct clinical setting. In our article, we review the CT diagnosis of arterial, venous, and nonocclusive intestinal ischemia. We discuss the vascular anatomy, pathophysiology of intestinal ischemia, CT techniques for optimal imaging, key and ancillary radiological findings, and differential diagnosis.

Imaging the postoperative patient: long-term complications of gastrointestinal surgery

OBJECTIVES

The objectives of this review are (1) to become acquainted with the long-term complications of surgery of the gastrointestinal tract, and (2) to appreciate the appropriate use of imaging in the assessment of long-term complications.

BACKGROUND

Gastrointestinal tract surgery comprises a group of procedures performed for a variety of both benign and malignant diseases. In the late postoperative setting, adhesions and internal hernias are the most important complications. and they can be further complicated by volvulus and ischemia. At present, computed tomography (CT) is the workhorse for evaluating late postoperative complications. Accurate imaging assessment of patients is essential for adequate treatment planning.

IMAGING FINDINGS OR PROCEDURE DETAILS

In this pictorial essay we will review the most frequent long-term complications after gastrointestinal surgery, including adhesions, afferent loop syndrome, closed-loop obstruction, strangulated obstruction, internal hernias, external hernias, anastomotic strictures and disease recurrence. Examples will be depicted using iconography from the authors' imaging department.

CONCLUSIONS

Knowledge of the most frequent complications after gastrointestinal surgery in the late postoperative period is of paramount importance for every radiologist, so that potentially life-threatening situations can be promptly diagnosed and adequate therapy can be planned.

TEACHING POINTS

• Long-term postoperative complications of gastrointestinal tract surgery can be divided into procedure-related and disease-related categories. • The most common procedure-related complications are internal hernias and adhesions. • The most frequent disease-related complications are mainly associated with neoplastic or inflammatory recurrence. • Computed tomography is the most useful examination when such complications are suspected.

Radiological Diagnosis of Portal/Mesenteric Vein Occlusion

Background

In contrast to an acute occlusion of the visceral arteries, which is the most important differential diagnosis for an occlusion of the portal venous system and which poses a highly dangerous situation ending in gangrene of the bowel wall, the symptoms of an acute occlusion of the portal venous system are quite unspecific. To rule out an acute arterial occlusion, diagnostic evaluation has to be carried out quickly in order to decide on the necessity of therapeutic steps concerning a recanalization of the occluded vessels. Only few therapeutic options are available to recanalize and remodel the portal venous system, depending on the underlying disease, the age of the occlusion, its extension, and the effect on the bowel wall, stomach, spleen, and abdominal wall. Moreover, the efficacy of recanalization procedures mainly depends on the formation and number of collateral venous blood supply, its degree, and the anatomic structure. Possible complications of portal hypertension like varices, gastrointestinal vasculopathy, ascites, and splenomegaly also influence the success of recanalization procedures. Only in cases of acute thrombotic occlusion systemic lytic therapy promises to be successful. Therefore, other options such as transjugular intrahepatic recanalization, e.g. by means of the TIPS (transjugular intrahepatic portosystemic shunt) procedure, have to be evaluated.

Methods

Review of the literature.

Results

Noninvasive methods such as ultrasound (US), computed tomography, and especially magnetic resonance imaging (MRI) allow the evaluation of therapeutic options as well as their success, the feasibility of technical procedures, the detection of possible risks, and a calculation of risks and benefits.

Conclusion

In order to arrive at the correct therapeutic decision, a combination of MRI and US methods combined with color Doppler guarantee the most efficient diagnostic results in cases with acute or chronic occlusions of the portal venous system.