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

Relative CT number of periappendiceal fat stranding may be an applicable index for estimating the severity of acute appendicitis

Objectives:

To investigate the feasibility of relative CT numbers to periappendiceal fat attenuation as an applicable index for estimating the severity of acute appendicitis.

Methods:

In total, 308 consecutive surgery-confirmed acute appendicitis patients and 243 controls with available preoperative CT were analyzed retrospectively. The radiological parameters were appendix diameter, length, and wall thickness as concurrent appendicitis signs. CT numbers of periappendiceal fat, mesenteric fat, subcutaneous fat in the anterior and posterior abdominal wall, retroperitoneal fat, gluteal subcutaneous fat and psoas major muscle were measured, as well as the relative CT numbers of periappendiceal fat compared with other locations.

Results:

There were 287 suppurative acute appendicitis (SAA) and 21 gangrenous or perforated acute appendicitis (GPAA) cases confirmed by pathology. The CT number of periappendiceal fat was significantly higher in patients than in controls (P＜0.01) although there was a wide overlap (−72.33 HU–117.43 HU). Significant differences in relative CT numbers were observed between the groups in gluteal subcutaneous fat (R_CTgl) and psoas major muscle (R_CTps) (P＜0.01). The AUCs of R_CTgl and R_CTps showed high accuracy to discriminate acute appendicitis from controls (AUC = 0.803, 0.761; 0.854, 0.847) and GPAA from SAA (AUC = 0.905, 0.851).

Conclusions:

Attenuation of periappendiceal fat on CT is related to the severity of appendicitis, and relative CT numbers (R_CTgl and R_CTps) could be an applicable index for severity determination.

Advances in knowledge:

Periappendiceal fat infiltration is related to the severity of acute appendicitis (especially relative CT number). Other clinical and CT features also need to be considered in the evaluation of inflammation.

Utility of Computed Tomography Overreading and Abdominal Ultrasound in Children With Suspected Appendicitis and Nondiagnostic Computed Tomography at Community Hospitals

OBJECTIVE

The aim of the study was to examine the ability of overreading of computed tomography (CT) and right lower quadrant ultrasound (RLQ US) to diagnose appendicitis for children with suspected appendicitis with equivocal CTs at community hospitals.

METHODS

This was a retrospective chart review of all children transferred to a children's hospital from community emergency departments with suspected appendicitis over 2 years for whom both CT and RLQ US were performed.

RESULTS

One hundred eighty-four children were included with a median age of 10.8 years, and 57.6% were female. Community hospitals documented that CTs were equivocal for appendicitis in 110 (59.8%), positive in 63 (34.2%), and negative in 11 (6.0%). Ninety-seven CTs (88.1%) designated equivocal at community hospitals were later deemed interpretable by pediatric radiologists: 21 (19.1%) as appendicitis and 76 (69.1%) as normal. In 13 children (11.8%), both the community and children's hospital CT interpretations were equivocal. In equivocal cases, RLQ US was consistent with appendicitis in 6 (46.2%), normal in 5 (41.7%), and nondiagnostic in 2. κ value between CT interpretations at community versus children's hospital was 0.13 (95% confidence interval, 0.05-0.22), and κ value between CT interpretation at the children's hospital and RLQ US was 0.59 (95% confidence interval, 0.48-0.70).

CONCLUSIONS

Most CTs deemed equivocal for appendicitis at community hospitals were interpretable by pediatric radiologists. In a few children for whom CTs were designated nondiagnostic, RLQ US provided a definitive diagnosis in almost 90% of cases. The first step in evaluation of children with suspected appendicitis for whom outside CTs are deemed equivocal should be to have the study reinterpreted by a pediatric radiologist.

Validation of a Scoring System to Distinguish Uncomplicated From Complicated Appendicitis

BACKGROUND

Studies have shown that uncomplicated appendicitis can be treated conservatively with antibiotics. It is important to select only those patients with uncomplicated appendicitis when considering conservative management. Recently, a scoring system based on clinical evaluation and ultrasound was developed to improve this selection and aid in shared decision making when considering an antibiotics-first strategy. The aim of this study was to externally validate the scoring system.

MATERIALS AND METHODS

A retrospective cohort study of all adult patients presenting to the emergency department between January 2014 and January 2017 with suspected acute appendicitis based on clinical evaluation and ultrasound was performed. For every patient, a score was calculated using the previously described scoring system. A final diagnosis, subdivided into complicated appendicitis, uncomplicated appendicitis, complicated alternative disease, and uncomplicated alternative disease, was assigned to every patient based on operative findings.

RESULTS

A total of 678 patients with suspected acute appendicitis based on clinical and ultrasonography findings were identified, of whom 175 (25.8%) had complicated appendicitis, 491 (72.4%) had uncomplicated appendicitis, and 12 (1.8%) had an alternative disease. Of the 678 patients, 272 had a score of five points or less, of whom 17 (6.2%) had complicated appendicitis, giving a negative predictive value of 93.8%.

CONCLUSIONS

With the scoring system based on clinical and ultrasonography features, 93.8% of patients predicted to have uncomplicated appendicitis were correctly identified. The scoring system could help identify patients suitable for conservative management in future studies.

Acute diverticulitis: Key features for guiding clinical management

Diverticular disease of the colon and small bowel is an important cause of pathology leading to emergency department visits and urgent gastrointestinal surgery. CT is a highly sensitive and specific modality for the diagnosis of acute diverticulitis and its complications as well as for the exclusion of alternate causes of pathology. Ultrasound, MRI and virtual CT colonoscopy have important adjunct roles for screening and workup of complications in specific patient populations. While diverticular disease most commonly involves the descending and sigmoid colon, it can also affect the proximal colon and small bowel. Acute diverticulitis may be categorized as uncomplicated or complicated according to the degree of inflammatory changes and related complications it induces, although some degree of overlap exists in clinical practice. Uncomplicated diverticulitis is classically characterized by localized inflammation surrounding a diverticulum ranging from wall thickening and phlegmonous change to the development of small, localized pericolic abscesses. Complicated forms of disease manifest with larger pericolic and distant abscesses, fistulae to adjacent organs, perforation, and peritonitis. Recurrent episodes of diverticulitis may lead to muscular hypertrophy of the bowel wall and luminal narrowing, potentially leading to bowel obstruction. Several imaging features may help to differentiate diverticulitis from colonic malignancy, however this remains a diagnostic imaging challenge that often requires further evaluation with colonoscopy. In this review, we discuss the pathophysiology and key imaging features of acute diverticulitis and its complications. We explore both common and uncommon presentations of the disease involving the colon and small bowel, acute and chronic manifestations of disease, and pitfalls to recognize when imaging alone may be insufficient to distinguish benign from malignant.

Portal phase alone is equivalent to multiphasic phase for CT diagnosis of acute non-traumatic pains in an emergency context

OBJECTIVES

To evaluate radiological diagnosis concordance between a simplified and a multiphasic computed tomography (MCT) protocol for patients presenting acute non-traumatic abdominal pains (ANTAE).

METHODS

During five consecutive months, all patients admitted in an emergency department for ANTAE were retrospectively included if they underwent MCT, including at least pre-contrast phase, late arterial phase (LAP), and portal venous phase (PVP). Clinical cases of suspected hemorrhagic conditions were secondarily excluded. For the study, two image sets, pre-contrast phase + LAP + PVP ± late phase called S1 and PVP alone called S2, were reviewed independently to give the most appropriate diagnosis with 5-point confidence scale. Diagnosis concordance and radiation dose were compared for each set of protocol by chi-square test. Linear mixed model was used to assess changes of diagnostic confidence and radiation dose.

RESULTS

All in all, 196 patients were included. The kappa coefficient between S1 and S2 was excellent (98.5%, CI_95% 95.6-99.7). Three errors due to an inappropriate protocol were observed (1.5%; CI_95% = - 0.2 to 3.2%), 2 related to biliary tract obstruction causes and one due to gastric bleeding not suspected on clinical data. S2 was associated with a 61% decrease of the radiation dose (p = 0.01) with a mild decrease of the confidence scale (4.54 ± 0.05 versus 4.74 ± 0.03, p = 0.001).

CONCLUSION

Using PVP-CT alone or MCT is equivalent for the diagnosis of ANTAE if suspected acute hemorrhages are excluded. A simplified CT protocol is associated with a dose decrease of 61%.

The Current Role of Radiologic and Endoscopic Imaging in the Diagnosis and Follow-Up of Colonic Diverticular Disease

OBJECTIVE

Colonic diverticular disease is among the most prevalent conditions in Western society and is a common cause for outpatient visits and hospitalizations. The role of imaging is in evolution, but it has proven useful in confirming clinically suspected disease, assessing severity and complications, and directing patient management.

CONCLUSION

This review focuses on the current role of radiologic and endoscopic imaging in distinct clinical scenarios of diverticular disease, with emphasis on diverticulitis and its follow-up.

Relative accuracy of emergency CT in adults with non-traumatic abdominal pain

OBJECTIVE

CT examination prior to emergency laparotomy has become ubiquitous in contemporary clinical practice, but the relative accuracy of CT in this context has not been widely reported. The aim of this study was to determine the accuracy and strength of agreement between the perceived pre-operative CT diagnosis and operative findings.

METHODS

Data from patients undergoing pre-operative CT prior to emergency laparotomy from January 2013 to June 2014 in a large teaching hospital were analysed. The CT diagnosis was compared with operative findings using the χ(2) test and weighted kappa statistic (Kw). Results were further analysed related to the time of day the CT was reported, anatomical location and grade of the reporting radiologist.

RESULTS

361 patients [median age 67 years (18-98 years); 180 males] underwent CT prior to emergency laparotomy. CT reports were deemed accurate in 318 (88.1%) cases and inaccurate in 43 (11.9%) cases, which resulted in 5 negative laparotomies in this latter cohort (11.6%, χ(2) 37.50, df 1; p < 0.0001). Accuracy and strength of agreement varied with anatomical location of the pathology; upper gastrointestinal (UGI) 75.5%, Kw 0.673 (0.531-0.815; p < 0.001); small bowel 89.9%, Kw 0.781 (0.687-0.875, p < 0.001); lower gastrointestinal (LGI) 90.4%, Kw 0.821 (0.749-0.893; p < 0.001). CT examinations reported within normal working hours had higher strength of agreement [Kw 0.832 (0.768-0.896), p < 0.001] than CTs reported out of hours [Kw 0.789 (0.721-0.857), p < 0.001], but there was no significant difference in overall accuracy (89.9 vs 86.0%; χ(2) 1.306, df 1, p = 0.253). Reporter seniority was not associated with improved diagnostic accuracy (χ(2) 1.825, df 1; p = 0.177).

CONCLUSION

CT agreement with emergency operative pathology was good to excellent, but the strength of agreement varied in relation to anatomical location of pathology.

ADVANCES IN KNOWLEDGE

Overall accuracy was 88.1% with good to excellent agreement between pre-operative CT and emergency laparotomy findings in adult patients with non-traumatic abdominal pain in the acute setting. Diagnostic accuracy of CT reporting varies with anatomical location of pathology.

Scoring system to distinguish uncomplicated from complicated acute appendicitis

Background

Non-operative management may be an alternative for uncomplicated appendicitis, but preoperative distinction between uncomplicated and complicated disease is challenging. This study aimed to develop a scoring system based on clinical and imaging features to distinguish uncomplicated from complicated appendicitis.

Methods

Patients with suspected acute appendicitis based on clinical evaluation and imaging were selected from two prospective multicentre diagnostic accuracy studies (OPTIMA and OPTIMAP). Features associated with complicated appendicitis were included in multivariable logistic regression analyses. Separate models were developed for CT and ultrasound imaging, internally validated and transformed into scoring systems.

Results

A total of 395 patients with suspected acute appendicitis based on clinical evaluation and imaging were identified, of whom 110 (27·8 per cent) had complicated appendicitis, 239 (60·5 per cent) had uncomplicated appendicitis and 46 (11·6 per cent) had an alternative disease. CT was positive for appendicitis in 284 patients, and ultrasound imaging in 312. Based on clinical and CT features, a model was created including age, body temperature, duration of symptoms, white blood cell count, C-reactive protein level, and presence of extraluminal free air, periappendiceal fluid and appendicolith. A scoring system was constructed, with a maximum possible score of 22 points. Of the 284 patients, 150 had a score of 6 points or less, of whom eight (5·3 per cent) had complicated appendicitis, giving a negative predictive value (NPV) of 94·7 per cent. The model based on ultrasound imaging included the same predictors except for extraluminal free air. The ultrasound score (maximum 19 points) was calculated for 312 patients; 105 had a score of 5 or less, of whom three (2·9 per cent) had complicated appendicitis, giving a NPV of 97·1 per cent.

Conclusion

With use of novel scoring systems combining clinical and imaging features, 95 per cent of the patients deemed to have uncomplicated appendicitis were correctly identified as such. The score can aid in selection for non-operative management in clinical trials.

Inter-observer reliability of computed tomographic classifications of diverticulitis

AIM

The wide use of computed tomography (CT) for diverticulitis has initiated new classifications, but their reliability has not been studied. The aim of the study was to assess the inter-observer agreement of radiologists on the classifications of diverticulitis.

METHOD

A set of 100 CT examinations of patients with an episode of diverticulitis was used to assess inter-observer agreement. Cases were derived from two prospective trials and a retrospective cohort to comprise an evenly distributed case mix of patients. The reference standard was the modified Hinchey classification based on all available information. Three blinded radiologists independently read all CT examinations. We calculated the proportion of agreement and kappa values for the Hinchey and Ambrosetti classifications. For the Dharmarajan classification only inter-observer agreement was calculated.

RESULTS

The agreement with the reference standard was substantial for both the modified Hinchey and the Ambrosetti classifications (P = 0.68 and P = 0.76). Overall inter-observer agreement for the modified Hinchey classification was substantial (median kappa 0.72), for the Ambrosetti classification almost perfect (median kappa 0.83) and for the Dharmarajan classification substantial (median kappa 0.76).

CONCLUSION

The Ambrosetti classification is more reproducible than the modified Hinchey and Dharmarajan classifications. The Ambrosetti and modified Hinchey classifications have a substantial agreement with the reference standard and therefore produce a reliable classification. The Dhamarajan is applicable only in complicated diverticulitis and is an important complementary classification to the other more general classifications of diverticulitis.

Journal club: Acute abdominal pain in elderly patients: effect of radiologist awareness of clinicobiologic information on CT accuracy

OBJECTIVE

The purpose of this study was to assess whether the availability of clinicobiologic findings would affect the diagnostic performance of CT of elderly emergency department patients with nontraumatic acute abdominal pain.

MATERIALS AND METHODS

The cases of 333 consecutively registered patients 75 years old or older presenting to the emergency department with acute abdominal pain and who underwent CT were retrospectively reviewed by two radiologists blinded or not to the patient's clinicobiologic results. Diagnostic accuracy was calculated according to the level of correctly classified cases in both the entire cohort and a surgical subgroup and was compared between readings performed with and without knowledge of the clinicobiologic findings. Agreement between each reading and the reference diagnosis and interobserver agreement were assessed with kappa statistics.

RESULTS

In both the entire cohort (87.4% vs 85.3%, p = 0.07) and the surgical group (94% vs 91%, p = 0.15), there was no significant difference in CT accuracy between diagnoses made when the radiologist was aware and those made when the radiologist was not aware of the clinicobiologic findings. Agreement between the CT diagnosis and the final diagnosis was excellent whether or not the radiologist was aware of the clinicobiologic findings.

CONCLUSION

In the care of elderly patients, CT is accurate for diagnosing the cause of acute abdominal pain, particularly when it is of surgical origin, regardless of the availability of clinical and biologic findings. Thus CT interpretation should not be delayed until complete clinicobiologic data are available, and the images should be quickly transmitted to the emergency physician so that appropriate therapy can be begun.

A triad algorithm for analysing individual ante- and post-mortem findings to improve the quality of intensive care

Autopsy is an important source of data for education and quality control. The aim of this study was comparison of ante- to post-mortem findings to detect weak points of intensive care unit (ICU) care. Patients who died in our 14-bed university medical ICU care and underwent an autopsy examination over 20 months (September 2007 to May 2009) were included. Modified Goldman's criteria were used to categorise discrepancies between diagnoses and post-mortem findings. A triad algorithm was constructed to analyse individual ante- to post-mortem findings. One hundred and seventy post-mortem examinations were conducted (45.6% autopsy rate). Major diagnostic discrepancies were detected in 20 patients (11.8%); four class I (2.4%) and 16 class II (9.4%). Massive pulmonary embolism with cardiac arrest was the most common class I discrepancy (75%). Triad analysis of major class I discrepancies showed that all patients had a history of chronic disease; the majority (75%) had a short ICU length of stay. In 75% adequate tests were used to detect disorders. There were interpretation problems of bedside data in complex emergency clinical conditions, especially with less experienced ICU physicians. Inappropriate or incorrectly interpreted diagnostic procedures were performed in more than half of cases with class II discrepancies (9/16, 56%). Abdominal ultrasonography was misleading in 31% (5/16) cases with class II discrepancies. In conclusion, triad algorithm analysis revealed problematic interpretation of bedside diagnostics in emergency cases by inexperienced physicians in class I major discrepancies detected at autopsy. No correct test and wrong interpretation of abdominal ultrasonography were major causes of class II discrepancies.

Management of diverticulitis: results of a survey among gastroenterologists and surgeons

AIM

The study aimed to investigate current management strategies for left-sided diverticulitis and compare them with current international guidelines. Differences between surgeons and gastroenterologists and between gastrointestinal and nongastrointestinal surgeons were assessed.

METHOD

A web-based survey of treatment options for uncomplicated and complicated diverticulitis was carried out among surgeons and gastroenterologists in the Netherlands. Only surgeons were asked about surgical strategy.

RESULTS

A total of 292 surgeons and 87 gastroenterologists responded, representing 92% of all surgical and 46% of all gastroenterology departments. Ninety per cent of respondents treated mild diverticulitis without antibiotics. About one-fifth (18% gastroenterologists; 19% surgeons) regarded a CT scan as mandatory in the initial assessment. Most surgeons and gastroenterologists used some form of bowel rest, would consider outpatient treatment and would perform a colonoscopy on follow up. For Hinchey Stage 3, 78% of surgeons would consider resection and primary anastomosis and laparoscopic lavage was viewed as a valid alternative by 30% of gastrointestinal and 2% of nongastrointestinal surgeons. For Hinchey stage 4, 46% of gastrointestinal and 72% of nongastrointestinal surgeons would always perform Hartmann's procedure.

CONCLUSION

The treatment of diverticulitis in the Netherlands shows major differences when compared with guidelines for all stages of disease.

A comparison of the accuracy of ultrasound and computed tomography in common diagnoses causing acute abdominal pain

Objectives

Head-to-head comparison of ultrasound and CT accuracy in common diagnoses causing acute abdominal pain.

Materials and methods

Consecutive patients with abdominal pain for >2 h and <5 days referred for imaging underwent both US and CT by different radiologists/radiological residents. An expert panel assigned a final diagnosis. Ultrasound and CT sensitivity and predictive values were calculated for frequent final diagnoses. Effect of patient characteristics and observer experience on ultrasound sensitivity was studied.

Results

Frequent final diagnoses in the 1,021 patients (mean age 47; 55% female) were appendicitis (284; 28%), diverticulitis (118; 12%) and cholecystitis (52; 5%). The sensitivity of CT in detecting appendicitis and diverticulitis was significantly higher than that of ultrasound: 94% versus 76% (p < 0.01) and 81% versus 61% (p = 0.048), respectively. For cholecystitis, the sensitivity of both was 73% (p = 1.00). Positive predictive values did not differ significantly between ultrasound and CT for these conditions. Ultrasound sensitivity in detecting appendicitis and diverticulitis was not significantly negatively affected by patient characteristics or reader experience.

Conclusion

CT misses fewer cases than ultrasound, but both ultrasound and CT can reliably detect common diagnoses causing acute abdominal pain. Ultrasound sensitivity was largely not influenced by patient characteristics and reader experience.

Abdominal separation in an adult male patient with acute abdominal pain

We report a male patient with prolonged post-prandial abdominal distension and a sudden onset of epigastric pain initially diagnosed as acute abdomen. The patient had no history of surgery. Physical examination revealed peritonitis and abdominal computed tomography scan showed upper abdominal mesentery intorsion. The patient then underwent surgical intervention. It was found that the descending mesocolon dorsal root was connected to the ascending colon and formed a membrane encapsulating the small intestine. The membrane also formed an orifice in the ileal pars caeca, from which a 30 cm herniated ileum formed a “C”-shaped loop which was strangulated by the orifice. An abdominal separation was diagnosed after surgery. We liberated the membranous peritoneum which incarcerated the intestinal canal from the root of ileocecal junction to Treitz ligament, and reduced the small intestinal malrotation. The patient had an uneventful recovery after operation with his abdominal distention disappeared during the follow-up. Abdominal separation is a rare situation, which may be related with embryo development. Surgery is a choice of treatment for it.

Abdominal pain in the ED: a 35 year retrospective

OBJECTIVE

Research published in 1972 and 1993 has detailed the demographics, diagnoses, and diagnostic test utilization of adult patients presenting with nontraumatic abdominal pain to the emergency department (ED) at the University of Virginia Hospital. This is an update of those studies, designed to examine the present state of diagnosis and management of abdominal pain, as well as to look at trends during the 35-year span of the investigations.

METHODS

One thousand consecutive adult patients presenting in the year 2007 with abdominal pain as their chief complaint were included in the analysis. Demographic data, discharge diagnosis, disposition, ED length of stay, charges, and diagnostic test utilization information were gathered and analyzed using electronic databases.

RESULTS

These patients represented 6.5% of the total ED census. Sixty-five percent were female, 24.7% hospitalized, and 21% diagnosed with undifferentiated abdominal pain. Relative to 1993, there were more patients receiving specific diagnoses, (79% versus 75%) and a higher rate of hospitalization (24.7% versus 18.3%). Use of diagnostic testing has markedly increased in frequency, most notably computed tomography and ultrasound, which have risen 6-fold. One of these imaging modalities is now used in 42% of patient encounters. Visit times were longer and patient charges higher. There were 2 cases of missed surgical disease in 2007 compared with 1 in 1993 and 8 in 1972.

CONCLUSION

Over the past 35 years, ED management of atraumatic abdominal pain has become time, money, and resource intense. Widespread use of sophisticated imaging has had a small impact on diagnostic specificity but has not produced lower admission rates or fewer cases of missed surgical illness.

Imaging patients with acute abdominal pain

Acute abdominal pain may be caused by a myriad of diagnoses, including acute appendicitis, diverticulitis, and cholecystitis. Imaging plays an important role in the treatment management of patients because clinical evaluation results can be inaccurate. Performing computed tomography (CT) is most important because it facilitates an accurate and reproducible diagnosis in urgent conditions. Also, CT findings have been demonstrated to have a marked effect on the management of acute abdominal pain. The cost-effectiveness of CT in the setting of acute appendicitis was studied, and CT proved to be cost-effective. CT can therefore be considered the primary technique for the diagnosis of acute abdominal pain, except in patients clinically suspected of having acute cholecystitis. In these patients, ultrasonography (US) is the primary imaging technique of choice. When costs and ionizing radiation exposure are primary concerns, a possible strategy is to perform US as the initial technique in all patients with acute abdominal pain, with CT performed in all cases of nondiagnostic US. The use of conventional radiography has been surpassed; this examination has only a possible role in the setting of bowel obstruction. However, CT is more accurate and more informative in this setting as well. In cases of bowel perforation, CT is the most sensitive technique for depicting free intraperitoneal air and is valuable for determining the cause of the perforation. Imaging is less useful in cases of bowel ischemia, although some CT signs are highly specific. Magnetic resonance (MR) imaging is a promising alternative to CT in the evaluation of acute abdominal pain and does not involve the use of ionizing radiation exposure. However, data on the use of MR imaging for this indication are still sparse.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/content/253/1/31/suppl/DC1.

Diagnostic accuracy of noncontrast computed tomography for appendicitis in adults: a systematic review

STUDY OBJECTIVE

We seek to determine the diagnostic test characteristics of noncontrast computed tomography (CT) for appendicitis in the adult emergency department (ED) population.

METHODS

We conducted a search of MEDLINE, EMBASE, the Cochrane Library, and the bibliographies of previous systematic reviews. Included studies assessed the diagnostic accuracy of noncontrast CT for acute appendicitis in adults by using the final diagnosis at surgery or follow-up at a minimum of 2 weeks as the reference standard. Studies were included only if the CT was completed using a multislice helical scanner. Two authors independently conducted the relevance screen of titles and abstracts, selected studies for the final inclusion, extracted data, and assessed study quality. Consensus was reached by conference, and any disagreements were adjudicated by a third reviewer. Unenhanced CT test performance was assessed with summary receiver operating characteristic curve analysis, with independently pooled sensitivity and specificity values across studies.

RESULTS

The search yielded 1,258 publications; 7 studies met the inclusion criteria and provided a sample of 1,060 patients. The included studies were of high methodological quality with respect to appropriate patient spectrum and reference standard. Our pooled estimates for sensitivity and specificity were 92.7% (95% confidence interval 89.5% to 95.0%) and 96.1% (95% confidence interval 94.2% to 97.5%), respectively; the positive likelihood ratio=24 and the negative likelihood ratio=0.08.

CONCLUSION

We found the diagnostic accuracy of noncontrast CT for the diagnosis of acute appendicitis in the adult population to be adequate for clinical decisionmaking in the ED setting.