Accuracy of computed tomography in predicting appendiceal perforation

doi:10.1016/j.jpedsurg.2009.10.040

Journal of Pediatric Surgery

Volume 45, Issue 1, January 2010, Pages 231-235

https://doi.org/10.1016/j.jpedsurg.2009.10.040 Get rights and content

Abstract

Background

Some surgeons use nonoperative management with or without interval appendectomy for patients who present with perforated appendicitis. These strategies depend on accurately delineating perforation by computed tomography (CT). Since 2005, our institution has used an evidence-based definition for perforation as a hole in the appendix or fecalith in the abdomen. This has been shown to clearly separate those with a high risk of abscess from those without. To quantify the ability of CT to identify which patients would meet these criteria for perforation, we tested 6 surgeons and 2 radiologists who evaluated blinded CT scans.

Methods

A junior and senior surgical residents, 2 staff interventional radiologists, and 4 attending pediatric surgeons with 3 to 30 years of experience reviewed 200 CT scans of pediatric patients who had undergone a laparoscopic appendectomy. All CT scans were reviewed electronically, and the reviewers were blinded to the results, outcome, and intraoperative findings. None of the patients had a well-formed abscess on CT. The reviewers were asked to decide only on perforated or nonperforated appendicitis according to our intraoperative definition. Clinical admission data were reviewed and compared between groups.

Results

In total, the reviewers were correct 72% of the time with an overall sensitivity of 62% and a specificity of 81%. The overall positive predictive value was 67%, and the negative predictive value was 77%.

Conclusions

This study shows that in the absence of a well-formed abscess, the triage of patient care based on a preoperative diagnosis of perforation from CT may be imprudent and subject a portion of the population to an unnecessarily prolonged course of care.

Section snippets

Methods

A file of 200 patients who had a preoperative CT scan and subsequently underwent appendectomy was compiled by our clinical research coordinator. All patients were treated from the time when we began enrolling in appendicitis trials under the definition of perforation as a hole in the appendix or a fecalith in the abdomen. The list comprised 101 patients with perforation and 99 without. Blinded to the previous radiologic read and operative findings, each CT was evaluated by a total of 8

Results

The results of each reviewer's interpretation of the CTs are listed below in Table 1, Table 2. In total, the reviewers were correct 72% of the time. The overall sensitivity of CT on predicting appendiceal perforation was 62% and the specificity was 81%. The overall positive predictive value was 67% and negative predictive value was 77%. Three reviewers (attending 1 and radiologists 1 and 2) commented on the presence of an appendiceal wall defect in a total of 55 cases, 41 of which were found to

Discussion

Nonoperative management of perforated appendicitis is predicated upon accurate and reliable interpretation of the available imaging. Computed tomography has been shown to be accurate in diagnosing acute appendicitis, with most reported sensitivities and specificities ranging around 90% [12], [13], [14]. There has also been a concordant decrease in the negative appendectomy rates from the previously accepted 15% to 20% to 2% to 12% with the use of CT as a diagnostic adjunct [12], [13], [14], [15]

References (27)

EinS.H. et al.
Is interval appendectomy necessary after rupture of an appendiceal mass?
J Pediatr Surg
(1996)
PuapongD. et al.
Routine interval appendectomy in children is not indicated
J Pediatr Surg
(2007)
ChenC. et al.
Current practice patterns in the treatment of perforated appendicitis in children
J Am Coll Surg
(2003)
KogutK.A. et al.
The association of elevated percent bands on admission with failure and complications of interval appendectomy
J Pediatr Surg
(2001)
AprahamianC.J. et al.
Failure in the nonoperative management of pediatric ruptured appendicitis: predictors and consequences
J Pediatr Surg
(2007)
HortonM.D. et al.
A prospective trial of computed tomography and ultrasonography for diagnosing appendicitis in the atypical patient
Am J Surg
(2000)
St PeterS.D. et al.
An evidence-based definition for perforated appendicitis derived from a prospective randomized trial
J Pediatr Surg
(2008)
TsaoK. et al.
Management of pediatric acute appendicitis in the computed tomographic era
J Surg Res
(2008)
YeungK.W. et al.
Evaluation of perforated and nonperforated appendicitis with CT
Clin Imaging
(2004)
TsukadaK. et al.
CT is useful for identifying patients with complicated appendicitis
Dig Liver Dis
(2004)

WuC.T. et al.

A retrospective study of CT findings in cases undergoing appendectomy at a single hospital

Clin Imaging

(2007)

LevinT. et al.

Nonoperative management of perforated appendicitis in children: can CT predict outcome?

Pediatr Radiol

(2007)

Garcia PeñaB.M. et al.

Ultrasonography and limited computed tomography in the diagnosis and management of appendicitis in children

JAMA

(1999)

Cited by (29)

Appendicitis in Children
2023, Advances in Pediatrics
Uterine abscess as an appendicitis complication: a case report
2022, Journal of Medical Imaging and Radiation Sciences
Citation Excerpt :
MRI is complementary to CT and US as a problem-solving modality. However, due to the low sensitivity rate for perforated appendicitis, triage of appendicitis based solely on imaging findings for conservative treatment is still inaccurate [9,10]. In this case, we used US initially for the preliminary diagnosis of acute appendicitis then used contrast-enhanced CT.
Acute appendicitis is a frequent cause of abdominal pain that requires surgical intervention. Rarely complications such as appendico-vesical, appendico-cutaneous, or appendico-uterine fistula formation may occur.
We present a case of an 83-year-old woman who suffered from a very rare complication of acute appendicitis. Multimodal radiologic examination including ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI) revealed complicated appendicitis with an abscess formation involving the right adnexal region and uterine cavity. The patient was treated conservatively with percutaneous drainage of the abscess and IV antibiotics.
Acute appendicitis is one of the common causes of emergency surgery. It is important to differentiate simple and complicated appendicitis to determine the best treatment option, thus, the diagnostic accuracy of certain US and CT findings in making this differentiation has been the subject of investigation. Even though some imaging findings suggest appendiceal perforation, deciding a conservative treatment plan based solely on imaging findings is still inaccurate. MRI is complementary to CT and US as a problem solving modality in certain situations.
This case report reminds us that physicians and radiologists should be aware of rare complications of acute appendicitis such as fistula formation to visceral organs. MRI is superior in order to differentiate complex fluid collections such as abscess formations.
L'appendicite aiguë est une cause fréquente de douleur abdominale qui nécessite une intervention chirurgicale. Dans de rares cas, des complications telles que la formation de fistules appendico-vésicales, appendico-cutanées ou appendico-utérines peuvent survenir.
Cas and résultats: Nous présentons le cas d'une femme de 83 ans qui a souffert d'une complication très rare de l'appendicite aiguë. Un examen radiologique multimodal comprenant une échographie, une tomodensitométrie (TDM) et une imagerie par résonance magnétique (IRM) a révélé une appendicite compliquée avec formation d'un abcès touchant la région annexielle droite et la cavité utérine. La patiente a été traitée de manière conservatrice avec un drainage percutané de l'abcès et des antibiotiques par voie intraveineuse.
L'appendicite aiguë est l'une des causes fréquentes de chirurgie d'urgence. Il est important de différencier l'appendicite simple de l'appendicite compliquée afin de déterminer la meilleure option thérapeutique. C'est pourquoi la précision diagnostique de certains résultats de l'échographie et de la tomodensitométrie dans cette différenciation a fait l'objet de recherches. Même si certains résultats d'imagerie suggèrent une perforation de l'appendice, le choix d'un plan de traitement conservateur basé uniquement sur l'imagerie reste imprécis. L'IRM est complémentaire de la TDM et de l'échographie en tant que modalité de résolution des problèmes dans certaines situations.
Ce rapport de cas nous rappelle que les médecins et les radiologues doivent être conscients des complications rares de l'appendicite aiguë telles que la formation de fistules vers les organes viscéraux. L'IRM est supérieure afin de différencier les collections complexes de liquide telles que les formations d'abcès.
Evaluation of Preoperative Clinical and Serological Determinations in Complicated Acute Appendicitis: A Score for Predicting Complicated Appendicitis
2021, Cirugia Espanola
Los parámetros clínicos y analíticos de la apendicitis aguda (AA) son la base diagnóstica. Se analiza la diferencia de sus valores según la histología para distinguir las AA simples de las complicadas.
Análisis observacional retrospectivo que incluye pacientes (> 14 años) que ingresan con diagnóstico de AA desde el 1 abril 2014 al 31 julio 2016. Histopatológicamente se dividen en AA complicada (perforada y/o gangrenada) y AA no complicada (flemonosa). Entre los 2 grupos se compara sexo, edad, temperatura al ingreso, duración de sintomatología, recuento leucocitario preoperatorio (WBC), porcentaje de neutrófilos, volumen plaquetario medio (VPM), índice de distribución de plaquetas (PDW), proteína C-reactiva (PCR) y estancia hospitalaria.
Se analizan 335 pacientes y se incluyen 284, de los cuales 194 (68,3%) tienen AA no complicada (AAnc) y 90 (31,7%) AA complicada (AAc). La edad, la duración de sintomatología, el porcentaje de neutrófilos, la PCR y la estancia hospitalaria son mayores en la AAc (p < 0,05). Las diferencias de las medias entre AAnc y AAc son: edad 13,2 años (IC 95%: 8,2-18,2), duración de sintomatología 14,1 h (IC 95%: 6,3-21,9), porcentaje de neutrófilos 5,0% (IC 95%: 3,2-6,8), PCR 73,6 mg/l (IC 95%: 50,0-97,2) y estancia hospitalaria 2,2 días (IC 95%: 1,4-3,0), con p < 0,05. Un modelo basado en parámetros preoperatorios (edad, duración de sintomatología, porcentaje de neutrófilos y PCR) se calcula para predecir la posibilidad de AAc. El área bajo la curva del modelo es 0,80 (IC 95%: 0,75-0,85).
El modelo predice la posibilidad de desarrollar AAc, pero debe validarse de manera prospectiva.
To analyze whether clinical and analytical parameters differ according to histopathology in cases of acute appendicitis (AA).
This is a retrospective, observational study including patients (>14 years of age) admitted for suspicion of AA from 1 April 2014 to 31 July 2016. Histopathology was divided into complicated (including perforated and gangrenous AA) and uncomplicated appendicitis (phlegmonous). Sex, age, temperature of patients on admission to the Emergency Department, symptom duration, preoperative white blood cell (WBC) count, neutrophil percentage, mean platelet volume (MPV), platelet distribution width (PDW), C-reactive protein (CRP) and hospital stay were compared in the two groups.
Three hundred and thirty-five patients were analyzed, and 284 were included. Appendicitis was uncomplicated in 194 (68.3%) and complicated in 90 (31.7%). Age, symptom duration, neutrophil percentage, CRP and hospital stay were higher in the complicated AA group (P < .05). The mean differences between uncomplicated and complicated AA were: age 13.2 years (95% CI: 8.2-18.2), symptom duration 14.1 hours (95% CI: 6.3-21.9), neutrophil percentage 5.0% (95% CI: 3.2-6.8), CRP 73.6 mg/l (95% CI: 50.0-97.2) and hospital stay 2.2 days (95% CI: 1.4-3.0), with p<0.05 for all these variables. A model based on the preoperative parameters (age, symptom duration, neutrophil percentage and CRP) was calculated to predict the likelihood of complicated AA. The receiver operating characteristic (ROC) of the model had an area under the curve of 0.80 (95% CI 0.75-0.85).
This model is able to diagnose complicated AA without the need for imaging techniques, although it must be validated with prospective analysis.
Validation of a Scoring System to Distinguish Uncomplicated From Complicated Appendicitis
2021, Journal of Surgical Research
Citation Excerpt :
The presence of features like an appendicolith or extraluminal free air means that the patient has a high chance of having complicated appendicitis, but the absence of these features do not rule out complicated appendicitis.17,18 Imaging lacks the ability to distinguish between complicated and uncomplicated appendicitis.14–20 A trial comparing the antibiotic treatment of appendicitis with appendectomy used CT imaging results as sole criterium to differentiate between uncomplicated and complicated appendicitis but still found that up to 17.6% of patients had complicated appendicitis during surgery.12
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.
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.
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%.
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.
Can ultrasound reliably identify complicated appendicitis in children?
2018, Journal of Surgical Research
Citation Excerpt :
CT scan sensitivity and specificity for the diagnosis of appendicitis have been demonstrated at around 90% in multiple studies.14,18 However, in a 2010 study conducted at a pediatric hospital, the overall sensitivity and specificity of CT for predicting appendiceal perforation were 62% and 81%, respectively, whereas PPV and NPV were 67% and 77%, respectively.19 Previous studies have demonstrated that certain findings on ultrasound, such as abscess or presence of an appendicolith in a child younger than 8 y, are specific for perforation.20
The ability of ultrasound to identify specific features relevant to nonoperative management of pediatric appendicitis, such as the presence of complicated appendicitis (CA) or an appendicolith, is unknown. Our objective was to determine the reliability of ultrasound in identifying these features.
We performed a retrospective study of children who underwent appendectomy after an ultrasound at four children's hospitals. Imaging, operative, and pathology reports were reviewed. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of ultrasound for identifying CA based on pathology and intraoperative findings and an appendicolith based on pathology were calculated. CA was defined as a perforation of the appendix. Equivocal ultrasounds were considered as not indicating CA.
Of 1027 patients, 77.5% had simple appendicitis, 16.2% had CA, 5.4% had no evidence of appendicitis, and 15.6% had an appendicolith. Sensitivity and specificity of ultrasound for detecting CA based on pathology were 42.2% and 90.4%; the PPV and NPV were 45.8% and 89.0%, respectively. Sensitivity and specificity of ultrasound for detecting CA based on intraoperative findings were 37.3% and 92.7%; the PPV and NPV were 63.4% and 81.4%, respectively. Sensitivity and specificity of ultrasound for detecting an appendicolith based on pathology were 58.1% and 78.3%; the PPV and NPV were 33.1% and 91.0%, respectively. Results were similar when equivocal ultrasound and negative appendectomies were excluded.
The high specificity and NPV suggest that ultrasound is a reliable test to exclude CA and an appendicolith in patients being considered for nonoperative management of simple appendicitis.
Childhood Appendicitis: Is Time Really of the Essence?
2017, Journal of Emergency Medicine

View all citing articles on Scopus

: Presented at the 40th Annual Meeting of the American Pediatric Surgical Association, Fajardo, Puerto Rico, May 28-June 1, 2009.

View full text

APSA papersAccuracy of computed tomography in predicting appendiceal perforation

Abstract

Background

Methods

Results

Conclusions

Section snippets

Methods

Results

Discussion

J Pediatr Surg

J Pediatr Surg

J Am Coll Surg

J Pediatr Surg

J Pediatr Surg

Am J Surg

J Pediatr Surg

J Surg Res

Clin Imaging

Dig Liver Dis

Clin Imaging

Nonoperative management of perforated appendicitis in children: can CT predict outcome?

Pediatr Radiol

Ultrasonography and limited computed tomography in the diagnosis and management of appendicitis in children

JAMA

APSA papers
Accuracy of computed tomography in predicting appendiceal perforation