Multidetector CT in emergency radiology: acute and generalized non-traumatic abdominal pain

Current use of artificial intelligence in the diagnosis and management of acute appendicitis

INTRODUCTION

Acute appendicitis is a common and time-sensitive surgical emergency, requiring rapid and accurate diagnosis and management to prevent complications. Artificial intelligence (AI) has emerged as a transformative tool in healthcare, offering significant potential to improve the diagnosis and management of acute appendicitis. This review provides an overview of the evolving role of AI in the diagnosis and management of acute appendicitis, highlighting its benefits, challenges, and future perspectives.

EVIDENCE ACQUISITION

We performed a literature search on articles published from 2018 to September 2023. We included only original articles.

EVIDENCE SYNTHESIS

Overall, 121 studies were examined. We included 32 studies: 23 studies addressed the diagnosis, five the differentiation between complicated and uncomplicated appendicitis, and 4 studies the management of acute appendicitis.

CONCLUSIONS

AI is poised to revolutionize the diagnosis and management of acute appendicitis by improving accuracy, speed and consistency. It could potentially reduce healthcare costs. As AI technologies continue to evolve, further research and collaboration are needed to fully realize their potential in the diagnosis and management of acute appendicitis.

The role of radiology in diagnosing gastrointestinal tract perforation

Spontaneous, iatrogenic or surgical perforation of the whole gastrointestinal wall can lead to serious complications, resulting in increased morbidity and mortality. Optimal patient management requires early clinical appraisal and prompt imaging evaluation. Both radiologists and referring clinicians should recognize the importance of choosing the ideal imaging modality and the usefulness of oral and rectal contrast medium. Surgeons and radiologists should be familiar with CT and fluoroscopy findings of the normal and pathologic anatomy after esophageal, stomach or colon surgery. Specifically, they should be able to differentiate innocuous from clinically-relevant, life-threatening postoperative complications to guide appropriate treatment. Advantages of esophagram, CT-esophagram, CT after rectal contrast enema and other imaging modalities are discussed.

Dirty Mass sign of abdominal imaging: A case of silent pneumoperitoneum

Pneumoperitoneum is a common complication after penetrating abdominal trauma, gastric ulcer, or colitis in which free air is present in the peritoneal or retroperitoneal space. Sole pneumoretroperitoneum, which refers to gas in the retroperitoneal space, is a rare entity, and when significant, results in a characteristic radiographic sign known as "Dirty Mass." Common causes include penetrating trauma or perforation of the retroperitoneal portions of the gastrointestinal tract (duodenum, ascending colon, descending colon, and rectum). Our case describes a 59-year-old female admitted for sudden onset RLQ abdominal pain with Dirty Mass sign on abdominal KUB. Early recognition of these key radiographic findings accelerates management and reduces the risk of developing complications.

Incidental diagnosis of intestinal perforation on a 99mTc DTPA renogram

Perforation of the bowel can be a life-threatening condition and is usually clinically diagnosed when a patient presents with such features as severe abdominal pain, tenderness, and tachycardia. Bowel perforation may be corroborated by various conventional imaging modalities, including X-ray, ultrasonography, computed tomography, and magnetic resonance imaging. Nuclear medicine imaging modalities seldom have a role to play in these settings. Rarely diagnosis of perforation may be missed if it is concealed and does not present with the usual signs. Mostly the perforation will eventually be diagnosed if they develop signs and symptoms and is taken up for an exploratory laparotomy. A delay in diagnosis can later lead to significant patient morbidity or even mortality. This report describes a case where possible intestinal perforation was suspected on a 99mTc-DTPA renogram in a postoperative patient with significant urine leak, the presence of which was confirmed intraoperatively. To our knowledge, this was the first such case in the literature.

The Role of Dual-Energy CT in Solid Organ Injury

The liver, spleen, and kidneys are the commonest injured solid organs in blunt and penetrating trauma. The American Association for the Surgery of Trauma (AAST) Organ Injury Scale (OIS) is the most widely accepted system for categorizing traumatic injuries. Grading systems allow clear communication of findings between clinical teams and assign a measurable severity of injury, which directly correlates with morbidity and mortality. The 2018 revised AAST OIS emphasizes reliance on CT for accurate grading; in particular regarding vascular injuries. Dual-Energy CT (DECT) has emerged as a promising tool with multiple clinical applications already demonstrated. In this review article, we summarize the basic principles of CT attenuation to refresh the minds of our readers and we scrutinize DECT's technology as opposed to conventional Single-Energy CT (SECT). This is followed by outlining the benefits of various DECT postprocessing techniques, which authors of this article refer to as the 3Ms (Mapping of Iodine, Material decomposition, and Monoenergetic virtual imaging), in aiding radiologists to confidently assign an OIS as well as problem solve complex injury patterns. In addition, a thorough discussion of changes to the revised AAST OIS focusing on definitions of key terms used in reporting injuries is described.

3D-printed iodine-ink CT phantom for radiomics feature extraction - advantages and challenges

BACKGROUND

To test and validate novel CT techniques, such as texture analysis in radiomics, repeat measurements are required. Current anthropomorphic phantoms lack fine texture and true anatomic representation. 3D-printing of iodinated ink on paper is a promising phantom manufacturing technique. Previously acquired or artificially created CT data can be used to generate realistic phantoms.

PURPOSE

To present the design process of an anthropomorphic 3D-printed iodine ink phantom, highlighting the different advantages and pitfalls in its use. To analyze the phantom's X-ray attenuation properties, and the influences of the printing process on the imaging characteristics, by comparing it to the original input dataset.

METHODS

Two patient CT scans and artificially generated test patterns were combined in a single dataset for phantom printing and cropped to a size of 26 × 19 × 30 cm3 . This DICOM dataset was printed on paper using iodinated ink. The phantom was CT-scanned and compared to the original image dataset used for printing the phantom. The water-equivalent diameter of the phantom was compared to that of a patient cohort (N = 104). Iodine concentrations in the phantom were measured using dual-energy CT. 86 radiomics features were extracted from 10 repeat phantom scans and the input dataset. Features were compared using a histogram analysis and a PCA individually and overall, respectively. The frequency content was compared using the normalized spectrum modulus.

RESULTS

Low density structures are depicted incorrectly, while soft tissue structures show excellent visual accordance with the input dataset. Maximum deviations of around 30 HU between the original dataset and phantom HU values were observed. The phantom has X-ray attenuation properties comparable to a lightweight adult patient (∼54 kg, BMI 19 kg/m2 ). Iodine concentrations in the phantom varied between 0 and 50 mg/ml. PCA of radiomics features shows different tissue types separate in similar areas of PCA representation in the phantom scans as in the input dataset. Individual feature analysis revealed systematic shift of first order radiomics features compared to the original dataset, while some higher order radiomics features did not. The normalized frequency modulus |f(ω)| of the phantom data agrees well with the original data. However, all frequencies systematically occur more frequently in the phantom compared to the maximum of the spectrum modulus than in the original data set, especially for mid-frequencies (e.g., for ω = 0.3942 mm-1 , |f(ω)|original  = 0.09 * |fmax |original and |f(ω)|phantom  = 0.12 * |fmax |phantom ).

CONCLUSIONS

3D-iodine-ink-printing technology can be used to print anthropomorphic phantoms with a water-equivalent diameter of a lightweight adult patient. Challenges include small residual air enclosures and the fidelity of HU values. For soft tissue, there is a good agreement between the HU values of the phantom and input data set. Radiomics texture features of the phantom scans are similar to the input data set, but systematic shifts of radiomics features in first order features, due to differences in HU values, need to be considered. The paper substrate influences the spatial frequency distribution of the phantom scans. This phantom type is of very limited use for dual-energy CT analyses.

A scoping review on acute gastrointestinal surgical complications in immunocompromised pediatric patients

Background

Gastrointestinal complications are becoming increasingly more common and pose a significant risk on the health of children with compromised immunity caused by various etiologies such as chemotherapy and posttransplantation immunosuppression. We aim to review abdominal complications in immunocompromised children and their respective management.

Main body

This is a scoping review of the literature. PubMed, MEDLINE, Google Scholar, and Scopus libraries were searched for relevant articles. Extracted data included the etiologies of immunocompromised immunity, gastrointestinal and abdominal complications in immunocompromised children, diagnosis, and treatment of these pathologies. Examples of gastrointestinal complications in immunocompromised children include, but not limited to, neutropenic enterocolitis, acute appendicitis, bowel perforation, acalculous cholecystitis, and acute pancreatitis. Our literature review showed that bacterial and fungal infections are the major causes of exacerbation and mortality. The main cause of immunosuppression in children with neutropenic enterocolitis and acute pancreatitis is chemotherapy, and management of these pathologies using intravenous fluids, antibiotic therapy, and granulocyte-stimulating factors is the current standard of care. Surgical intervention is uncommon and reserved for complicated cases. That said, in acute appendicitis and bowel perforation, laparoscopy is the mainstay treatment. However, in systemic infections, nonsurgical interventions such as transfusion and bowel rest are the gold standard. As for acalculous cholecystitis, percutaneous cholecystectomy is superior to laparotomy and other surgical interventions.

Conclusion

Timely diagnosis and management of gastrointestinal complications in the immunocompromised children is key in reducing mortality and morbidity. Both surgical and nonsurgical interventions are needed and should be further studied in order to improve outcomes.

Dual-energy CT of acute bowel ischemia

Acute bowel ischemia is a condition with high mortality and requires rapid intervention to avoid catastrophic outcomes. Swift and accurate imaging diagnosis is essential because clinical findings are commonly nonspecific. Conventional contrast enhanced CT of the abdomen has been the imaging modality of choice to evaluate suspected acute bowel ischemia. However, subtlety of image findings and lack of non-contrast or arterial phase images can make correct diagnosis challenging. Dual-energy CT provides valuable information toward assessing bowel ischemia. Dual-energy CT exploits the differential X-ray attenuation at two different photon energy levels to characterize the composition of tissues and reveal the presence or absence of faint intravenous iodinated contrast to improve reader confidence in detecting subtle bowel wall enhancement. With the same underlying technique, virtual non-contrast images can help to show non-enhancing hyperdense hemorrhage of the bowel wall in intravenous contrast-enhanced scans without the need to acquire actual non-contrast scans. Dual-energy CT derived low photon energy (keV) virtual monoenergetic images emphasize iodine contrast and provide CT angiography-like images from portal venous phase scans to better evaluate abdominal arterial patency. In Summary, dual-energy CT aids diagnosing acute bowel ischemia in multiple ways, including improving visualization of the bowel wall and mesenteric vasculature, revealing intramural hemorrhage in contrast enhanced scans, or possibly reducing intravenous contrast dose.

Performance of automatic machine learning versus radiologists in the evaluation of endometrium on computed tomography

PURPOSE

In this study, we developed radiomic models that utilize a combination of imaging features and clinical variables to distinguish endometrial cancer (EC) from normal endometrium on routine computed tomography (CT).

METHODS

A total of 926 patients consisting of 416 endometrial cancer (EC) and 510 normal endometrium were included. The CT images of these patients were segmented manually, and divided into training, validation, testing and external testing sets. Non-texture and texture features of these images with endometrium or uterus as region of interest were extracted. The clinical feature "age" was also included in the feature set. Feature selection and machine learning classifier were applied to normalized feature set. This manual optimized combination was then compared with the best pipeline exported by Tree-Based Pipeline Optimization Tool (TPOT) on testing and external testing set. The performances of these machine learning pipelines were compared to that of radiologists.

RESULTS

The manual expert optimized pipeline using the "reliefF" feature selection method and "Bagging" classifier on the external testing set achieved a test ROC AUC of 0.73, accuracy of 0.73 (95% CI 0.62-0.82), sensitivity of 0.64 (95% CI 0.45-0.79), and specificity of 0.78 (95% CI 0.65-0.87), while TPOT achieved a test ROC AUC of 0.79, accuracy of 0.80 (95% CI 0.70-0.87), sensitivity of 0.61 (95% CI 0.43-0.77), and specificity of 0.90 (95% CI 0.78-0.96). When compared to average radiologist performance, the TPOT achieved higher test accuracy (0.80 vs. 0.49, p < 0.001) and specificity (0.90 vs. 0.51, p < 0.001), with comparable sensitivity (0.61 vs. 0.46, p = 0.130).

CONCLUSION

Our results demonstrate that automatic machine learning can distinguish EC from normal endometrium on routine CT imaging with higher accuracy and specificity than radiologists.

Perforated Colon Cancer Associated With Post-operative Recurrent Bowel Perforations

Colon perforation is a major life-threatening condition associated with high morbidity and mortality, which often develops secondary to complicated diverticulitis and, less commonly, colon cancer. We describe the case of a 51-year-old female who had perforated colon cancer with concurrent diverticulosis. Based on history, physical exam, laboratory, and computed tomography (CT) findings on initial presentation, the patient was diagnosed with acute complicated diverticulitis. Despite medical treatment, the patient’s condition worsened, warranting exploratory laparotomy and a left hemicolectomy with transverse end colostomy creation. Surgical pathology revealed stage IIIC colon cancer without evidence of diverticulitis. The patient underwent eight cycles of adjuvant chemotherapy with FOLFOX (folinic acid, fluorouracil, and oxaliplatin). Over the next year, the patient experienced recurrent bowel perforations requiring repeated surgeries. Perforations were identified in both the small and large bowel on different occasions. Even though neither presented with a clear etiology, possible ischemic, infectious, erosive, and iatrogenic etiologies were on the differential. Our case exemplifies the mounting complications we should be wary of when performing repeated invasive abdominal operations.

Tailored versus fixed scan delay in contrast-enhanced abdominal multi-detector CT: An intra-patient comparison of image quality

PURPOSE

To perform anintra-patient comparison betweena single-pass protocol (SP) and a portal venous phase (PVP) by means ofboth quantitative and qualitative analysis of image quality.

METHODS

Forty patients (31 M; 9F; aged 20-77 years; BMI 23 ± 4 Kg/m²) underwent both a SP and a PVP using a 64-rows multi-detector CT with a median interval time of 56 days (range5-903). All patients underwent i.v. bolus injection (2.0 cc/sec) of 1.7 cc/Kg of a non ionic iodinated contrast-media (370 mgI/ml) with scan delays of 67 ± 8 and 90 s for the SP and the PVP, respectively. Signal- (SNR) and contrast-to-noise ratios (CNR) were calculated for most visceral organs and for both abdominal aorta (AA) and main portal vein (MPV). For qualitative analysis, reproduction of abdominal viscera and vascular structures was blindly evaluated and inter-observer agreement calculated by the weighted Cohen k-analysis.

RESULTS

Attenuation values (H.U.) of AA (232 ± 53vs180 ± 36) and MPV (215 ± 39vs187 ± 42) were significantly (p < 0.001) higher in the SP than in PVP, respectively. At qualitative analysis, reproduction of mostabdominal viscerawas also significantly sharper (p < 0.001) with the SP than the PVPwith inter-observer agreement scores (k)ranging from 0.60 to 0.88 for all but one imaging criteria.

CONCLUSIONS

As the SP resulted in a significantly higher vascular enhancement and in a sharper reproduction of most abdominal viscera, it may be better suited than a PVP for the CT evaluation of non traumatic acute abdomen.

Twelve tips for interpreting abdominal CT scans

BACKGROUND

Abdominal computerised tomography (CT) scans are a crucial tool in the diagnosis and management of the acute abdomen. Currently, medical students are not widely and extensively trained in the interpretation of abdominal scans.

AIM

We aim to provide advice about interpreting abdominal CT scans.

METHODS

We used the critical reflection of our experiences, both in clinical practice and in teaching, alongside advice from the literature to develop these tips.

RESULTS

Twelve tips following the '4As, 3Bs, 2Cs and 1D' approach are presented to assist doctors and medical students with interpreting abdominal CT scans.

CONCLUSION

The early identification of pathology on CT scans has been demonstrated to improve patient outcomes in certain cases, while a formal radiologist's report is awaited. Following a systematic approach, such as the one we presented here, may aid trainees in looking at abdominal CT scans.

Severe Pain in Chronic Pancreatitis Patients: Considering Mental Health and Associated Genetic Factors

Pain is the most distressing and disruptive feature of recurrent acute pancreatitis (RAP) and chronic pancreatitis (CP) resulting in low quality of life (QOL) and disabilities. There is no single, characteristic pain pattern in patients with RAP and CP. Abdominal imaging features of CP accurately reflect morphologic features but they do not correlate with pain. Pain is the major driver of poor quality of life (QOL) and it is the constant pain, rather than intermittent pain that drives poor QOL. Furthermore, the most severe constant pain experience in CP is also a complex condition. The ability to target the etiopathogenesis of severe pain requires new methods to detect the exact pain mechanisms in an individual at cellular, tissue, system and psychiatric levels. In patients with complex and severe disease, it is likely that multiple overlapping mechanisms are simultaneously driving pain, anxiety and depression. Quantitative sensory testing (QST) shows promise in detecting alterations in central processing of pain signals and to classify patients for mechanistic and therapeutic studies. New genetic research suggests that genetic loci for severe pain in CP overlap with genetic loci for depression and other psychiatric disorders, providing additional insights and therapeutic targets for individual patients with severe CP pain. Well-designed clinical trials that integrate clinical features, QST, genetics and psychological assessments with targeted treatment and assessment of responses are required for a quantum leap forward. A better understanding of the context and mechanisms contributing to severe pain experiences in individual patients is predicted to lead to better therapies and quality of life.

Diagnosis at gut point: rapid identification of pneumoperitoneum via point-of-care ultrasound

Undifferentiated abdominal pain is a common presentation often requiring immediate medical or surgical intervention. Providing an accurate diagnosis involves a detailed patient history and thorough physical exam. Point of care ultrasound is gaining acceptance as a rapid diagnostic tool that can be used to accurately detect life-threatening conditions while potentially avoiding unnecessary radiation exposure and facilitating rapid treatment. Detection of pneumoperitoneum with point-of-care ultrasound is a simple procedure that relies heavily on the experience of the investigating practitioner. Standard technique involves placing a high-frequency linear-array transducer in the right upper quadrant, where abdominal free air is most likely to accumulate. Detection of the 'gut point', which is the transition of abdominal wall sliding to lack thereof in a single image, is the pathognomonic finding of pneumoperitoneum. If visualization is difficult, moving the patient to the left lateral decubitus position or using the scissors technique can provide additional image views. This representative case report and review highlights the use of abdominal POCUS for the diagnosis of pneumoperitoneum. Ultrasound should continue to be explored by clinicians to narrow the differential diagnosis of acute abdominal pain.

Gastric Perforation with Omental Patch Repair: A Rare Complication of Pulmonary Resuscitation in COVID-19 Pneumonia

A 71-year-old male, diagnosed with coronavirus disease 2019 (COVID-19), was admitted to the medical-surgical floor for supportive treatment. The patient received bag-mask ventilation (BMV) secondary to severe hypoxia and reendotracheal intubation in the hospital on day eleven. A chest X-ray following reintubation noted concern for intra-abdominal air. Significant abdominal distention and subsequent diagnostic imaging showed pneumoperitoneum and a possible perforation of the stomach. The patient underwent an exploratory laparotomy with omental patching for a gastric perforation. Amidst the height of the COVID-19 pandemic, several important findings have been made through the disease sequelae of this individual patient.

The pediatric stomach - masses and mass-like pathology

Diagnostic imaging of pediatric gastric masses often provides a challenge for the practicing radiologist. Radiologists should be aware of this relatively unusual pathology, particularly in cross-sectional imaging findings. We will review pediatric gastric masses and mass-like lesions, focusing on neoplastic and inflammatory etiologies.

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.

Evaluation of the CT Scan as the First Examination for the Diagnosis and Therapeutic Strategy for Acute Cholecystitis

BACKGROUND

The CT scan has supplanted the abdominal ultrasound for emergency examinations. A comparison of CT scan and ultrasound performance for the diagnosis and management of acute cholecystitis in acute care was proposed. The hypothesis is that the CT scan may be sufficient for the diagnosis of acute cholecystitis, which would allow faster progress to surgery.

METHODS

The retrospective study of consecutive patients operated for acute cholecystitis or gallbladder distension with pre-operative imaging within 48 h in one centre.

RESULTS

Between 2015 and 2017, a total of 341 cholecystectomies were performed in our centre. The analysis involved 120 patients. Ultrasound had better sensitivity than the CT scan, respectively, 79.4% [70.5-86.6] and 52.3% [42.5-62.1], but less specificity, with 61.5% [31.6-86.1] and 92.3% [64.0-99.8], respectively. However, there was a significant difference in favour of the CT scan for the diagnosis of complicated cholecystitis (p 0.004). The positive likelihood ratio of complicated cholecystitis is better at CT scan (7.8) [2.7-23.1] than in ultrasound (1.0) [0.1-9.7]. CT scan and ultrasound are equivalent for the diagnosis of acute cholecystitis, but CT scan is more efficient for the diagnosis of complicated cases (Youden index J 0.3 vs 0.001).

CONCLUSION

It is possible to place the surgical indication of cholecystectomy on the only data of the CT scan. We propose a decision-making algorithm that uses the CT scan to make the diagnosis and decide on emergency treatment for complicated cases or that allows us to propose a delayed surgery for simple cholecystitis.

Concomitant leukocytosis and lymphopenia predict significant pathology at CT of acute abdomen: a case-control study

BACKGROUND

Acute abdominal pain accounts for about 10% of emergency department visits and has progressively become the primary indication for CT scanning in most centers. The goal of our study is to identify biological or clinical variables able to predict or rule out significant pathology (conditions requiring urgent medical or surgical treatment) on abdominal CT in patients presenting to an emergency department with acute abdominal pain.

METHODS

This was a retrospective cohort study performed in the emergency department of an academic center with an annual census of 60'000 patients. One hundred and-nine consecutive patients presenting with an acute non-traumatic abdominal pain, not suspected of appendicitis or renal colic, during the first semester of 2013, who underwent an abdominal CT were included. Two medical students, completing their last year of medical school, extracted the data from patients' electronic health record. Ambiguities in the formulations of clinical symptoms and signs in the patients' records were solved by consulting a board certified emergency physician. Nine clinical and biological variables were extracted: shock index, peritonism, abnormal bowel sounds, fever (> 38 °C), intensity and duration of the pain, leukocytosis (white blood cell count >11G/L), relative lymphopenia (< 15% of total leukocytes), and C-reactive Protein (CRP). These variables were compared to the CT results (reference standard) to determine their ability to predict a significant pathology.

RESULTS

Significant pathology was detected on CT in 71 (65%) patients. Only leukocytosis (odds ratio 3.3, p = 0.008) and relative lymphopenia (odds ratio 3.8, p = 0.002) were associated with significant pathology on CT. The joint presence of these two anomalies was strongly associated with significant pathology on CT (odds ratio 8.2, p = 0.033). Leukocytosis with relative lymphopenia had a specificity of 89% (33/37) and sensitivity of 48% (33/69) for the detection of significant pathology on CT.

CONCLUSION

The high specificity of the association between leukocytosis and relative lymphopenia amongst the study population suggests that these parameters would be sufficient to justify an emergency CT. However, none of the parameters could be used to rule out a significant pathology.