Abdominal pain: general imaging strategies

Acute abdominal pain is the most common condition necessitating surgical admission to a paediatric hospital. The vast majority of cases are due to either appendicitis or acute non-specific abdominal pain; however, there are many other conditions presenting with acute abdominal pain in childhood which can mimic appendicitis. Some of these conditions are rarely encountered in adult practice. Plain abdominal radiographs are still obtained initially on many children presenting with abdominal pain. In the absence of associated symptoms such as vomiting however, ultrasonography (US) is more likely to elucidate the underlying cause of pain than plain-film radiography. While computed tomography (CT) is being used extensively in investigating adults with abdominal pain, its widespread use in children is to be avoided in the interest of radiation protection.     

Nontraumatic abdominal emergencies: acute abdominal pain: diagnostic strategies

Common causes of acute abdominal pain include appendicitis, cholecystitis, bowel obstruction, urinary colic, perforated peptic ulcer, pancreatitis, diverticulitis, and nonspecific, nonsurgical abdominal pain. The topographic classification of acute abdominal pain (pain in one of the four abdominal quadrants, diffuse abdominal pain, flank or epigastric pain) facilitates the choice of the imaging technique. The initial radiological evaluation often consists of plain abdominal radiography, despite significant diagnostic limitations. The traditional indications for plain films--bowel obstruction, pneumoperitoneum, and the search of ureteral calculi--are questioned by helical computed tomography (CT). Although ultrasonography (US) is in many centers the modality of choice for imaging the gallbladder and the pelvis in children and women of reproductive age, CT is considered to be one of the most valued tools for triaging patients with acute abdominal pain. CT is particularly beneficial in patients with marked obesity, unclear US findings, bowel obstruction, and multiple lesions. The introduction of multidetector row CT (MDCT) has further enhanced the utility of CT in imaging patients with acute abdominal pain.     

The echographic diagnosis of acute appendicitis and its complications

The authors report their experience with emergency US in patients hospitalized for clinical suspicion of acute appendicitis or presenting with pain in the right lower abdominal quadrant. One hundred fifty-two patients were examined with US: 93/152 had pathologies of the right iliac region; 81 of them underwent surgery (50/81 appendectomies). In 27 of these patients the inflamed appendix presented with a typical US pattern. All of them had surgical confirmation. In 13/50 cases, US findings followed an atypical pattern (6 patients had a periappendiceal mass in the right iliac region, 3 had small amounts of fluid in the Douglas pouch, and 4 had gas-filled bowel loops of the ileum). The false negatives were 10/50. US sensitivity was 80%, and its specificity was 54%. The most common pathologic conditions are described whose symptoms mimic those of acute appendicitis. US role in inflamed acute appendicitis is still to be defined. Nonetheless, the authors suggest that US be performed on all patients with atypical pain in the lower abdominal quadrants, because of its high diagnostic accuracy in many common pathologies mimicking appendicitis, especially urinary and uterine adnexal pathologies.     

CT of appendicitis in children

Appendicitis is the most common condition requiring intraabdominal surgery in infancy and childhood. Yet, despite its common occurrence, accurate diagnosis remains challenging. Acute appendicitis may be missed at initial clinical examination in 28%-57% of children aged 12 years and younger and in nearly 100% of children under the age of 2 years. Diagnostic imaging has an ever-increasing role in the prompt and accurate diagnosis of acute appendicitis in the pediatric population. At the authors' institution, helical computed tomography (CT) is the primary tool for diagnosing or excluding appendicitis in children. Since its inception in 1998, helical CT with rectally administered contrast material has been shown to reduce the total number of inpatient observation days, laparotomies with negative findings, and per-patient cost. Helical CT is a highly sensitive and specific tool for diagnosing pediatric appendicitis and has resulted in a beneficial change in patient care in 68.5% of all patients seen in the authors' emergency department for suspected appendicitis. This includes both those patients who receive an eventual diagnosis of appendicitis and those who do not have the disease. Major strengths of limited helical CT with rectal contrast material include producing uniformly high published sensitivity and specificity values for diagnosis of appendicitis and enabling diagnosis of alternative conditions of acute abdominal pain in children. In contrast, limitations of graded-compression ultrasonography in children include highly operator-dependent sensitivity and specificity values and relative infrequency with which the normal appendix can be visualized in this population. Although there have been many exciting diagnostic advancements for the diagnosis of acute appendicitis in the pediatric population, the role of helical CT is far from clear. The purpose of this article is to describe a helical CT approach to imaging in children suspected of having acute appendicitis at a large urban pediatric teaching hospital and its effects on patient outcomes and hospital costs.     

Paediatric emergencies: non-traumatic abdominal emergencies

Presentation with acute abdominal pain or abdominal symptopathology is a very common cause of presentation of children to hospital. The causes are dependent in part on the age of the child, in part on the presence of previous surgery, and can be divided into those that relate to congenital abnormalities at whatever age they present, acquired disease and infection. Children, particularly young children are often poor historians, and therefore the clinical examination and the laboratory investigations are important in helping to come to a diagnosis. Primary imaging of abdominal emergencies in childhood is a radiograph of the abdomen, followed by ultrasound. Further imaging depends on the results of these studies. An ordered review of the abdomen radiograph is important if the salient features on X-ray are not to be missed. Practitioners should be competent with abdominal ultrasound in children and know where to seek the causes of disease, as these are different from those that are obtained in many instances in adults. Familiarity with the likely causes is important. The three commonest causes of acute abdominal pain in childhood are, in young infants, intussusception, appendicitis and mesenteric adenitis. In older children, inflammatory bowel disease and ovarian pathology are also included. This article details the approach to imaging and the salient features of some of the conditions. Electronic Publication     

儿内科急性阑尾炎诊治探讨

目的 探讨儿内科小儿急性阑尾炎的诊治特点。方法 对儿内科就诊的79例急性阑尾炎病例进行回顾性分析。结果 首次于儿内科就诊的79例急性阑尾炎病儿，均于就诊后24h内转入儿外科治疗，临床以腹痛、发热、末梢血白细胞及中性粒细胞增高为主要表现。74例经手术治疗后证实为急性阑尾炎，其中化脓性阑尾炎45例，坏疽性阑尾炎12例，蛔虫性阑尾炎1例，单纯性阑尾炎16例。36例发生阑尾穿孔，21例并发弥漫性腹膜炎。5例未手术治疗。结论 首次于儿科内科就诊的腹痛患儿，伴有发热、周围血白细胞或／和中性粒细胞增高，尤其有右下腹固定压痛者，鉴别除外儿内科常见腹痛性疾病，应考虑阑尾炎，并及时与儿外科医生联系，早期诊断，及时处理，减少并发症。     

MDCT of acute cecal conditions

The cecum comprises a relatively short segment of the gastrointestinal tract, but it can be affected by numerous acute conditions. Acute conditions may arise from processes primary to the cecum, such as volvulus, bascule, neoplasm, and trauma. Alternatively, acute conditions can be due to secondary to systemic or nearby pathology, such as infection, inflammatory processes, ischemia, and infarction. While it is common to suspect appendicitis as the etiology of acute right lower quadrant abdominal pain, the cecum should also be considered as a potential cause of pain, especially in the setting of an abnormal or absent appendix. Multi-detector computed tomography (MDCT) has evolved to become the best imaging modality to evaluate patients presenting with right lower quadrant abdominal pain or suspected acute cecal pathology. Strengths of MDCT include rapid acquisition of images, high spatial resolution, and ability to create multi-planar reconstructed images. In this pictorial review, we illustrate and describe key MDCT findings for various acute cecal conditions with which the emergency radiologist should be familiar.     

Imaging right lower quadrant pain: Not always appendicitis

Although acute appendicitis (AA) is one of the commonest causes of right lower quadrant abdominal pain (RLQP), there are numerous other conditions in the abdomen and pelvis that can simulate the clinical presentation of AA for which imaging is essential in detection. We discuss the approach to evaluation of patients presenting with acute onset RLQP and the choice of various imaging modalities that can be utilized. Although CT remains the workhorse in evaluation, US and MRI, given lack of radiation, play an important ancillary role, particularly in the pediatric and pregnant patients. We present a spectrum of conditions presenting with RLQP which we have classified systematically ranging from conditions affecting the bowel, mesentery/omentum/peritoneum, vasculature, urinary and reproductive systems to give the reader a checklist of conditions to consider when evaluating a case of RLQP.     

Accuracy of nonfocused helical CT for the diagnosis of acute appendicitis: a 5-year review

OBJECTIVE: The clinical usefulness of routine, nonfocused helical CT was evaluated in diagnosing acute appendicitis or providing an alternative diagnosis in patients presenting to the emergency department with acute lower abdominal pain. MATERIALS AND METHODS: We reviewed CT reports and clinical records of 650 consecutive adult patients who presented between January 1996 and December 2000 with right lower quadrant pain or lower abdominal pain and clinical findings suggestive of appendicitis. Helical CT was performed with oral contrast material in 610 cases (93.8%) and IV contrast in 572 cases (88.0%). Both vascular and enteric contrast media were administered in 544 cases (83.7%). Rectal contrast material was administered in 52 cases (8.0%). The abdomen was helically scanned from the dome of the diaphragm to the iliac crests with a collimation of 7 mm, from the iliac crests to the acetabular roof at a 5-mm collimation, from the acetabular roof to the symphysis pubis with a collimation of 5-10 mm. The surgical or clinical record was used for follow-up. RESULTS: Of the 650 patients, 552 (84.9%) had adequate clinical follow-up. There were 137 true-positive, eight false-positive, five false-negative, and 402 true-negative cases. The sensitivity, specificity, and accuracy of nonfocused helical CT were 96.5%, 98.0%, 97.6%, respectively. The positive and negative predictive values were 94.5% and 98.8%, respectively. In patients without acute appendicitis, CT suggested an alternative diagnosis, which clinically explained the patient's acute abdominal pain in 266 patients (66.2%). CONCLUSION: Nonfocused helical CT was highly accurate in diagnosing acute appendicitis or suggesting an alternative diagnosis in patients with acute lower abdominal pain or right lower quadrant pain.     

Segmental omental infarction

Acute right-sided abdominal pain is a common presenting symptom in the emergency department. Acute cholecystitis and acute appendicitis are the most likely etiologies for right upper and lower quadrant pain, respectively. However, other differential possibilities include right-sided diverticulitis and perforated colon carcinoma. This case report of an 18-year-old man with segmental omental infarction highlights a much less frequent, self-limited cause of right-sided abdominal pain, which is increasingly identified on computed tomography scans.     

Diagnosing acute appendicitis using a nonoral contrast CT protocol in patients with a BMI of less than 25

The objective of this study was to compare the accuracy for the diagnosis of appendicitis in patients presenting to the emergency department (ED) with acute, nontraumatic abdominal pain and a body mass index (BMI) of less than 25 before and after the implementation of a nonoral contrast computed tomography (CT) protocol with intravenous contrast. The IRB approved this HIPAA-compliant retrospective study; informed consent was waived. This study included 736 adult patients with a BMI of less than 25 presenting to our ED with acute, nontraumatic abdominal pain over two distinct 6-month time periods. An oral and intravenous contrast-enhanced protocol was utilized in the first cohort (group A), and an intravenous contrast-enhanced protocol without oral contrast was utilized in the second cohort (group B). Three abdominal fellowship-trained readers retrospectively reviewed all CT studies and electronic medical records, including surgical/pathology reports that served as reference standards. Group A consisted of 359 patients; 41 patients had surgically proven appendicitis. The sensitivity and specificity of the readers for diagnosing appendicitis in group A ranged from 95.2–100 and 98.1–99.5 %, respectively. Group B consisted of 372 patients; 39 had surgically proven appendicitis. The sensitivity and specificity of the readers in group B ranged from 92.0–100 and 98.6–100 %, respectively. There were no statistically significant differences in sensitivity or specificity for CT scans performed in groups A and B. In patients with a BMI of less than 25, an intravenous contrast-enhanced CT protocol without oral contrast demonstrates similar accuracy to an intravenous contrast-enhanced protocol with oral contrast for diagnosing acute appendicitis.     

Omental infarction in pediatric patients: sonographic and CT findings

OBJECTIVE: Children with omental infarction typically present with abdominal pain and are diagnosed clinically as having acute appendicitis. Our purpose was to perform a retrospective review of the imaging findings in nine children with omental infarction as an aid to radiologists in distinguishing this entity from acute appendicitis. CONCLUSION: In pediatric patients with omental infarction, both CT and sonography show a heterogeneous mass characteristically situated between the anterior abdominal wall and the colon. It is important for radiologists to recognize the characteristic imaging findings seen with omental infarction.     

Inter-observer agreement for abdominal CT in unselected patients with acute abdominal pain

The level of inter-observer agreement of abdominal computed tomography (CT) in unselected patients presenting with acute abdominal pain at the Emergency Department (ED) was evaluated. Two hundred consecutive patients with acute abdominal pain were prospectively included. Multi-slice CT was performed in all patients with intravenous contrast medium only. Three radiologists independently read all CT examinations. They recorded specific radiological features and a final diagnosis on a case record form. We calculated the proportion of agreement and kappa values, for overall, urgent and frequently occurring diagnoses. The mean age of the evaluated patients was 46 years (range 19–94), of which 54% were women. Overall agreement on diagnoses was good, with a median kappa of 0.66. Kappa values for specific urgent diagnoses were excellent, with median kappa values of 0.84, 0.90 and 0.81, for appendicitis, diverticulitis and bowel obstruction, respectively. Abdominal CT has good inter-observer agreement in unselected patients with acute abdominal pain at the ED, with excellent agreement for specific urgent diagnoses as diverticulitis and appendicitis.     

Appendicitis in children: color Doppler sonography.

The authors used color Doppler ultrasonography (US) to evaluate 33 children with suspected appendicitis and found locally increased blood flow in all of 10 patients with appendicitis or periappendiceal abscess; the studies were normal in 16 patients without appendicitis. The gray-scale sonographic results were concordant in all 26 of these patients. In two other patients with presumptive mesenteric adenitis and in one patient with a hemorrhagic ovarian cyst at gray-scale US, color Doppler imaging showed no increased perfusion and aided in confirming the absence of a significant inflammatory process. In four other children, color Doppler US clarified gray-scale sonographic findings that might have been confused with complicated appendicitis and aided in the diagnosis of other causes of acute abdominal pain. These findings indicate that color Doppler US is a useful adjunct to gray-scale US in evaluating children with suspected acute appendicitis.     

MRI evaluation of acute appendicitis in pregnancy

In recent years, magnetic resonance imaging (MRI) has become a valuable diagnostic tool for evaluation of acute abdominal pain in pregnancy. MRI offers an opportunity to identify the normal or inflamed appendix as well as a variety of other pathologic conditions that can masquerade clinically as acute appendicitis in pregnant women. Visualization of the normal appendix by MRI virtually excludes the diagnosis of acute appendicitis and may help reduce the negative laparotomy rate in this patient population. Here we discuss a comprehensive MRI protocol for evaluation of pregnant women with abdominal pain, focusing on the appearance and location of the normal and diseased appendix, and we describe an approach to diagnosing acute appendicitis and other conditions with MRI. J. Magn. Reson. Imaging 2013;37:566–575. © 2012 Wiley Periodicals, Inc.     

Appendicolith revealed on CT in children with suspected appendicitis: how specific is it in the diagnosis of appendicitis?

OBJECTIVE. The purpose of this study was to determine the sensitivity, specificity, and positive and negative predictive values of a diagnosis of appendicitis when CT without enteric contrast material reveals an appendicolith in children with suspected appendicitis. MATERIALS AND METHODS. A retrospective review of children who underwent abdominal CT for suspected appendicitis over a 25-month period was performed to identify patients with an appendicolith. An age-matched group of patients examined for trauma served as controls. RESULTS. CT was performed in 104 children. Appendicitis was present in 60 (58%) of 104 children; 39 (65%) of 60 had an appendicolith. Appendicitis was not present in 44 (42%) of 104; six (14%) of 44 had an appendicolith. An appendicolith detected on CT had a sensitivity of 65% and a specificity of 86% for the radiologist diagnosing appendicitis. An appendicolith had a positive predictive value of 74% and a negative predictive value of 26%. Among the control population, two (3%) of 74 children had an appendicolith. This number was statistically significant compared with children in the study group with an appendicolith and abdominal pain, but without appendicitis (p = 0.02). CONCLUSION. Although an appendicolith is significantly associated with appendicitis, the detection of an isolated appendicolith on CT is not sufficiently specific to be the sole basis for the diagnosis of acute appendicitis.     

Acute nontraumatic abdominal pain in adult patients: abdominal radiography compared with CT evaluation

PURPOSE: To compare the diagnostic yield of abdominal radiography with that of computed tomography (CT) in adult patients presenting to the emergency department with nontraumatic abdominal pain. MATERIALS AND METHODS: Records of 1,000 consecutive patients presenting to the emergency department with acute abdominal pain from April to June 1998 were retrospectively reviewed. A total of 871 patients underwent abdominal radiography, and 188 underwent abdominal CT. The report interpretations of the abdominal radiographs and CT scans were divided into normal, nonspecific, and abnormal categories. Final discharge diagnoses were compared with the interpretations of the imaging examination results, and sensitivities and specificities of each modality were calculated and compared. RESULTS: Interpretation of abdominal radiographs was nonspecific in 588 (68%) of 871 patients, normal in 200 (23%), and abnormal in 83 (10%). The highest sensitivity of abdominal radiography was 90% for intraabdominal foreign body and 49% for bowel obstruction. Abdominal radiography had 0% sensitivity for appendicitis, pyelonephritis, pancreatitis, and diverticulitis. Sensitivities of abdominal CT were highest for bowel obstruction and urolithiasis at 75% and 68%, respectively. CONCLUSION: Abdominal radiographs are not sensitive in the evaluation of adult patients presenting to the emergency department with nontraumatic abdominal pain.     

Acute epiploic appendagitis: CT findings in 33 cases

Acute epiploic appendagitis (AEA) is a benign self-limiting process presenting with acute abdominal pain often misdiagnosed clinically as either diverticulitis or appendicitis, but which has a pathognomonic CT appearance. The CT findings in 33 adult patients diagnosed by CT over a 33-month period as having AEA were retrospectively reviewed. The study group included 24 men and 9 women, with a mean age of 44.6 years. The mean age of the male patients was lower than that of the female patients, 40.9 vs 54.7 years. All patients presented with acute abdominal pain, mainly in the left (n=21) and right (n=9) lower quadrants, with localized tenderness in all patients and peritoneal irritation in 15 of them. Low-grade fever was found in 8 patients and mild leukocytosis in 16. Characteristic CT findings of an oval fatty mass with central streaky densities and surrounded by mesenteric stranding adjacent to the serosal surface of the colon were seen in all cases. Additional findings included mural thickening of the juxtaposed colon in 16 patients and peritoneal fluid in 7. One patient underwent surgery on the basis of an erroneous diagnosis of acute appendicitis. As CT is often used nowadays to evaluate various acute abdominal complaints, it may be the first imaging modality by which AEA is diagnosed. AEA should be included in the differential diagnosis in young male patients with localized left lower abdominal pain and tenderness. Electronic Publication     

Ultrasonography (US) in the assessment of pediatric non traumatic gastrointestinal emergencies

Background

Non traumatic gastrointestinal emergencies in the children and neonatal patient is a dilemma for the radiologist in the emergencies room and they presenting characteristics ultrasound features on the longitudinal and axial axis. The most frequent emergencies are : appendicitis, intussusceptions, hypertrophic pyloric stenosis, volvulus due to intestinal malrotation. The aim of this article is to familiarize the reader with the US features.

Methods

A retrospective analysis of 200 ultrasound examinations performed in neonatal and children patients with fever, abdominal pain, leukocytosis, vomiting and diarrhea were evaluated.

Results

Of 200 exame 50 cases of intussusceptions, 100 cases of appendicitis, 20 cases associated with abscess;10 gangrenous appendicitis with absence a color Doppler , and 10 cases of perforated appendicitis at tomography computer integration and 10 cases of volvulus was found.

Conclusions

Ultrasonography (US) is therefore rapidly becoming an important imaging modality for the evaluation of acute abdominal pain, particularly in pediatric patients, where satisfactory examination is often not achievable for the attending clinicians. US provides excellent anatomic detail on the longitudinally and axial axis .

     

Ultrasound of acute GI tract conditions

Patients with acute abdominal pain are a great challenge to the radiologist. The clinical diagnosis is classically unreliable, resulting in both negative laparotomies as well as ill-advised surgical delay in a large number of patients. Ultrasound offers a non-invasive way to decrease both false-negative and false-positive diagnoses in this category of patients. This article focuses on the role of sonography in the diagnosis of acute conditions of the gastrointestinal tract tract such as appendicitis, sigmoid diverticulitis, Crohn's disease, colitis, infectious ileocecitis caused by Yersinia, Campylobacter or Salmonella, right-sided colonic diverticulitis, bowel malignancy presenting acutely, small bowel obstruction, intussusception, omental infarction, and epiploic appendagitis. The sonographic spectrum of these conditions as well as possible pitfalls are discussed using illustrative case histories.