Targeted helical CT of the acute abdomen: appendicitis, diverticulitis, and small bowel obstruction

Comparison between survey radiography, B-mode ultrasonography, contrast-enhanced ultrasonography and contrast-enhanced multi-detector computed tomography findings in dogs with acute abdominal signs

Contrast-enhanced multi-detector computed tomography (CE-MDCT) is used routinely in evaluating human patients with acute abdominal symptoms. Contrast-enhanced ultrasound (CEUS) continues to be in its infancy as it relates to evaluation of the acute abdomen. The purpose of this study was to compare survey radiography, B-mode ultrasound, CEUS, and CE-MDCT findings in canine patients presenting with acute abdominal signs; with a focus on the ability to differentiate surgical from non-surgical conditions. Nineteen dogs were prospectively enrolled. Inclusion required a clinical diagnosis of acute abdominal signs and confirmed surgical or non-surgical causes for the clinical signs. Agreement for the majority of recorded imaging features was at least moderate. There was poor agreement in the identification of pneumoperitoneum and in the comparison of pancreatic lesion dimensions for B-mode vs. CEUS. The CT feature of fat stranding was detected in cases including, but not limited to, gastric neoplasia with perforation, pancreatitis, and small intestinal foreign body. Ultrasound underestimated the size and number of specific lesions when compared with CE-MDCT. Contrast-enhanced ultrasound was successful in detecting bowel and pancreatic perfusion deficits that CE-MDCT failed to identify. Accuracy for differentiation of surgical vs. non-surgical conditions was high for all modalities; 100%, 94%, and 94% for CE-MDCT, ultrasonography and survey radiography respectively. Findings indicated that CE-MDCT is an accurate screening test for differentiating surgical from non-surgical acute abdominal conditions in dogs. Focused CEUS following CE-MDCT or B-mode ultrasonography may be beneficial for identifying potentially significant hypoperfused lesions.

Feasibility for using dual-phase contrast-enhanced multi-detector helical computed tomography to evaluate awake and sedated dogs with acute abdominal signs

Canine patients with acute abdominal signs are often clinically unstable and need a rapid and accurate diagnosis. Contrast-enhanced multi-detector computed tomography (CT) is the current modality of choice for evaluating acute abdominal pain in people. We hypothesized that contrast-enhanced multi-detector CT would be a feasible and safe technique for use in awake and lightly sedated dogs with acute abdominal signs. Eighteen client-owned dogs were enrolled, all presenting with acute abdominal signs. Dogs were scanned using a dual-phase protocol that included precontrast, arterial, and portal venous phases. Eight dogs were scanned awake and ten were given light sedation as chosen by the primary care clinician. Two observers who were unaware of clinical findings and sedation status scored image quality for each scan by consensus opinion. Mean serum creatinine in the sedated group was higher than in the awake group but was within the normal reference range. Other laboratory and physiologic measures did not differ between awake and sedated groups. No IV contrast-related adverse reactions were seen. Median scan time for all patients was less than 10 min. Sixteen of 18 contrast-enhanced multi-detector CT scans were scored fair to excellent in diagnostic quality, with no statistical difference in diagnostic quality for awake vs. sedated patients. Causes for two poor quality diagnostic scans included severe beam hardening from previously administered barium contrast agent and severe motion artifacts. We conclude that dual-phase contrast-enhanced multi-detector CT is a feasible and safe technique for evaluating awake and minimally sedated dogs presenting with acute abdominal signs.

Diagnosis and management of complicated intra-abdominal infection in adults and children: guidelines by the Surgical Infection Society and the Infectious Diseases Society of America

Evidence-based guidelines for managing patients with intra-abdominal infection were prepared by an Expert Panel of the Surgical Infection Society and the Infectious Diseases Society of America. These updated guidelines replace those previously published in 2002 and 2003. The guidelines are intended for treating patients who either have these infections or may be at risk for them. New information, based on publications from the period 2003-2008, is incorporated into this guideline document. The panel has also added recommendations for managing intra-abdominal infection in children, particularly where such management differs from that of adults; for appendicitis in patients of all ages; and for necrotizing enterocolitis in neonates.

Diagnosis and Management of Complicated Intra-abdominal Infection in Adults and Children: Guidelines by the Surgical Infection Society and the Infectious Diseases Society of America

Evidence-based guidelines for managing patients with intra-abdominal infection were prepared by an Expert Panel of the Surgical Infection Society and the Infectious Diseases Society of America. These updated guidelines replace those previously published in 2002 and 2003. The guidelines are intended for treating patients who either have these infections or may be at risk for them. New information, based on publications from the period 2003–2008, is incorporated into this guideline document. The panel has also added recommendations for managing intra-abdominal infection in children, particularly where such management differs from that of adults; for appendicitis in patients of all ages; and for necrotizing enterocolitis in neonates.

Acute appendicitis: diagnostic value of nonenhanced CT with selective use of contrast in routine clinical settings

The purposes of this study were to determine the (1) frequency with which nonenhanced computed tomography (CT) (NECT) permits conclusive diagnosis of acute appendicitis, (2) accuracy of NECT when findings are conclusive, and (3) overall accuracy of a CT protocol consisting of NECT with selective use of contrast. Five hundred and thirty-six patients underwent a NECT protocol with selective use of contrast. Diagnostic accuracy was then determined separately for (1) patients with conclusive initial NECT, (2) patients with inconclusive initial NECT, and (3) all patients. NECT was conclusive on initial interpretation in 404/536 patients and inconclusive in 132/536. Of 132 inconclusive studies, 126 were repeated with contrast (intravenous, oral or rectal). Sensitivity, specificity, and positive and negative predictive value for diagnosis of acute appendicitis were (1) 90%, 96.0%, 84.8%, and 97.4% in patients with conclusive NECT (n = 404); (2) 95.6%, 92.3%, 73%, and 99% in patients with inconclusive NECT followed by repeat CT with contrast; and (3) 91.3%, 95%, 82%, and 98% in all patients. The initial diagnosis of appendicitis may be made by NECT in 75% of patients, with contrast administration reserved for inconclusive NECT studies.

Diagnostic pitfalls and accuracy of diagnosis in acute abdominal pain

OBJECTIVE

To identify the differential diagnostic difficulties in acute abdominal pain at the emergency department and during hospitalization.

MATERIAL AND METHODS

Patients with abdominal pain lasting for up to 7 days were registered during 1997-2000 and re-evaluated one year after discharge (n=2851).

RESULTS

Diagnoses with low sensitivity at the emergency department but markedly increased sensitivity at discharge were non-specific abdominal pain with a sensitivity value at the emergency department of 0.43, appendicitis 0.80, gallstones 0.68, constipation 0.74 and peptic ulcer 0.26. Corresponding kappa-values were 0.48, 0.74, 0.84, 0.88 and 0.93, respectively. Malignancy, gynaecological complaints, dyspepsia, urinary tract infection and diverticulitis displayed fairly good concordance between the preliminary and discharge judgements, but the predictive diagnostic value was still low at discharge. Sensitivity values at discharge were 0.40, 0.75, 0.73, 0.77 and 0.83, respectively. Among 479 surgically treated patients, 104 initially received a diagnosis usually not requiring surgery and had a median delay until operation of 22 h (95% CI 30-50 h), compared with 8 h (12-18 h) for referrals.

CONCLUSIONS

Non-specific abdominal pain is the main differential diagnostic problem in the emergency department also for diagnoses requiring surgery. Constipation is a diagnostic pitfall and when making this diagnosis a careful re-evaluation is necessary.

Multi-detector computed tomography of acute abdomen

Acute abdominal pain is one of the most common causes for referrals to the emergency department. The sudden onset of severe abdominal pain characterising the "acute abdomen" requires rapid and accurate identification of a potentially life-threatening abdominal pathology to provide a timely referral to the appropriate physician. While the physical examination and laboratory investigations are often non-specific, computed tomography (CT) has evolved as the first-line imaging modality in patients with an acute abdomen. Because the new multi-detector CT (MDCT) scanner generations provide increased speed, greater volume coverage and thinner slices, the acceptance of CT for abdominal imaging has increased rapidly. The goal of this article is to discuss the role of MDCT in the diagnostic work-up of acute abdominal pain.

CT Evaluation of Appendicitis and Its Complications: Imaging Techniques and Key Diagnostic Findings

OBJECTIVE

This article reviews various CT protocols for appendicitis, identifies key CT findings for diagnosing appendicitis, discusses unusual manifestations such as chronic and recurrent appendicitis, and profiles imaging features that differentiate appendicitis from other inflammatory and neoplastic ileocecal conditions. Patients were studied with helical CT.

CONCLUSION

CT is a highly accurate, noninvasive test for appendicitis, but the optimal CT technique is controversial. Major complications of appendicitis (perforation, abscess formation, peritonitis, bowel obstruction, septic seeding of mesenteric vessels, gangrenous appendicitis) and their management are discussed. Abdominal CT is a well-established technique in the study of acute abdominal pain and has shown high sensitivity and specificity for diagnosing and differentiating appendicitis, providing an accurate diagnosis in the early stages of disease.

The use of abdominal computed tomography in older ED patients with acute abdominal pain

The objectives of this study were to determine the prevalence of use of abdominal computed tomography (CT) in older ED patients with acute nontraumatic abdominal pain, describe the most common diagnostic CT findings, and determine the proportion of diagnostic CT results. This was a prospective, observational, multicenter study of 337 patients 60 years or older. History was obtained prospectively; charts were reviewed for radiographic findings, dispositions, diagnoses, and clinical course, and patients were followed up at 2 weeks for additional information. The prevalence of use of abdominal CT was 37%. The most common diagnostic findings were diverticulitis (18%), bowel obstruction (18%), nephrolithiasis (10%), and gallbladder disease (10%). Eight percent of patients had findings suggestive of neoplasm. Overall, 57% of CT results were diagnostic (95% confidence interval [CI], 49%-66%), 75% (95% CI, 63%-84%) for patients requiring acute medical or surgical intervention, and 85% (95% CI, 62%-97%) for patients requiring acute surgical intervention. CT use is highly prevalent in older ED patients with acute abdominal pain. CT results are often diagnostic, especially for patients with emergent conditions.

Caecal-diverticulitis: a rare differential diagnosis for right-sided lower abdominal pain

OBJECTIVE

There are several differential diagnoses for acute abdominal discomfort with pain referred to the right lower quadrant region. The objective of this report is to outline our experience with diverticulitis of the caecum, which is a rare condition that is particularly difficult to diagnose correctly pre-operatively.

METHODS

A retrospective analysis of acute diverticulitis of the caecum was performed over the period from January 1992 to December 2000 within the Surgical Department of the RWTH Aachen, Germany. The progress of each patient was assessed by interviewing the patient and by telephone contact with the patient's general practitioner.

RESULTS

Seven patients with isolated infective diverticulitis of the caecum were encountered in the course of this study. In five of these cases, the pre-operative diagnosis was either unclear or incorrect. Four patients underwent surgery for suspected appendicitis. In one patient, the diverticulitis was diagnosed during laparoscopic surgery undertaken for presumed adnexal disease. Intestinal continuity was restored in all cases. The postoperative course was uneventful.

CONCLUSIONS

Right-sided caecal diverticulitis is rare in comparison to diverticulitis of the sigmoid or descending colon. Nevertheless, it should be actively considered in the differential diagnosis of patients with acute tenderness in the right lower abdominal region.

Evaluation of early abdominopelvic computed tomography in patients with acute abdominal pain of unknown cause: prospective randomised study

OBJECTIVES

To evaluate the impact of early abdominopelvic computed tomography in patients with acute abdominal pain of unknown cause on length of hospital stay and accuracy of diagnosis.

DESIGN

Randomised, prospective controlled trial.

SETTING

Teaching hospital in England.

PARTICIPANTS

120 patients admitted with acute abdominal pain for which no immediate surgical intervention or computed tomography was indicated.

INTERVENTION

55 participants were prospectively randomised to early computed tomography (within 24 hours of admission) and 65 to standard practice (radiological investigations as indicated).

MAIN OUTCOME MEASURES

Length of hospital stay, accuracy of diagnosis, and, owing to a possible effect on inpatient mortality, deaths during the study.

RESULTS

Early computed tomography reduced the length of hospital stay by 1.1 days (geometric mean 5.3 days (range 1 to 31) v 6.4 days (1 to 60)), but the difference was non-significant (95% confidence interval, 8% shorter stay to 56% longer stay, P=0.17). Early computed tomography missed significantly fewer serious diagnoses. Seven inpatients in the standard practice arm died. Only 50% (59 of 118) of diagnoses on admission were correct at follow up at 6 months, but this improved to 76% (90) of diagnoses after 24 hours.

CONCLUSIONS

Early abdominopelvic computed tomography for acute abdominal pain may reduce mortality and length of hospital stay. It can also identify unforeseen conditions and potentially serious complications.

The role of colonoscopy in the diagnosis of appendicitis in patients with atypical presentations

BACKGROUND

Acute appendicitis is one of the most common causes of acute abdomen. Despite recent advances in radiologic imaging, the diagnosis of acute appendicitis may be difficult on occasion. The aims of this study were to describe the colonoscopic features of appendicitis and to determine whether colonoscopy can be used as an adjunct for the diagnosis of appendicitis in patients with atypical presentations.

METHODS

The colonoscopic findings in 21 patients (14 men, 7 women; average age 55 years) with a colonoscopic or histopathologic diagnosis of appendicitis were analyzed retrospectively. Colonoscopy was performed because diagnoses suggested by CT were other than acute appendicitis (11 patients), and/or the presenting clinical features were atypical for acute appendicitis with the duration of symptoms being 10 days or longer (17 patients).

RESULTS

The colonoscopic diagnosis was acute appendicitis for all 21 patients. Seventeen underwent appendectomy, the diagnosis being verified in all cases. Of the 4 patients whose symptoms improved without appendectomy, 3 were considered to have acute appendicitis because pus was seen to drain from the appendiceal orifice at colonoscopy. A definite diagnosis could not be made in the remaining 1 patient. Therefore, the diagnosis of appendicitis was considered confirmed in 20 of 21 patients. Colonoscopic findings in these 20 patients included hyperemia (15) and bulging (18) at the appendiceal orifice area with surrounding mucosal edema (19), and drainage of pus from the appendiceal orifice (7).

CONCLUSION

Colonoscopy may be useful in the diagnosis of appendicitis when the clinical presentation is atypical for appendicitis and/or imaging studies are nondiagnostic.

The prevalence and implications of incidental findings on ED abdominal CT scans

We reviewed reports from 321 consecutive emergency department (ED) noncontrast, helical "renal stone" abdominal CT scans obtained at a single medical center between April 1996 to June 1997 for incidental findings. Incidental findings were common (45% of scans), and approximately half were rated of "moderate" or "serious" concern by 2 independent reviewers (kappa = 0.72). ED records indicated that only 21% of incidental findings were documented, and only 11 (18%) of cases with findings of "moderate/severe" concern had evidence of follow-up on hospital chart review. Although work-up of these 11 cases did not yield any serious diagnoses, many potentially serious incidental findings without follow-up remain worrisome.