EBM
BLOK KEDOKTERAN KELUARGA
CRITICAL APPRAISAL
“Accuracy of low dose CT in the diagnosis of appendicitis in childhood and
comparison with USG and standard dose CT”
DISUSUN OLEH
SALSABILA AZMI QATRUNNADA (1102017207)
KELOMPOK KK13-20
Dosen Pembingbing
dr. Citra Fitri Agustina, Sp.KJ
FAKULTAS KEDOKTERAN
UNIVERSITAS YARSI
2020-2021
Case Illustration
A 6 year old female came to the ER with a four- our history of right lower quadrant
(RLQ) abdominal pain. The pain originated in the umbilical region, radiating diffusely across the
lower abdomen and subsequently localised to the RLQ. Based on the clinical presentation of this
patient, the initial impression pointed towards a provisional diagnosis of acute appendicitis.
Usually doctor has been considered USG, but the Doctor planned to use CT to prove the diagnosis.
However, CT must be performed carefully, because of the associated radiation exposure, and the
consequent risk of cancer. Finally, doctor used low dose CT to prove the diagnosis. Because many
reports have evaluated diagnoses made using low dose CT in adults and adolescents, and these
findings have been applied in clinical practice.
Introduction
Acute appendicitis is the most common abdominal disease requiring surgery in the pediatric
population. The incidence of appendicitis is relatively high in pediatric patients, and appendicitis
in these patients tends to be associated with higher rates of perforation. To prevent severe
complications, such as perforation, pan-peritonitis, or intra-abdominal abscess, early diagnosis and
prompt treatment, such as appendectomy, are important. In the past, the rate of negative or
unnecessary appendectomies was higher. With recent advances in imaging techniques, such as
ultrasonography (USG) or computed tomography (CT), the diagnostic accuracy of acute
appendicitis has improved, and negative appendectomy rates have been reduced.
Among these diagnostic modalities, USG has been considered a tool to aid in the diagnosis of
acute appendicitis over the last 30 years, and has been particularly useful for diagnosing
appendicitis in children, because it uses no ionizing radiation and is non-invasive. However, its
diagnostic accuracy varies, depending on the operator; moreover, making a diagnosis based on
USG findings is difficult in obese patients. Conversely, CT has a high sensitivity and specificity;
thus, it is a comparatively accurate diagnostic method, and consequently, the number of CT
examinations has increased considerably. Nevertheless, CT must be performed carefully, because
of the associated radiation exposure, and the consequent risk of cancer. Saito et al. reported various
methods that are currently used to diagnose pediatric appendicitis at different hospitals, but no
clear conclusion could be drawn regarding the effect of age or body mass index (BMI). With
magnetic resonance imaging (MRI), there is no exposure to ionizing. The scanner is safe during
pregnancy and the result of the examination is reliable and accurate. Nevertheless, MRI is not used
widely due to its high costs.
For these reasons, there is an increasing interest in low dose CT. Some studies on this subject have
been reported, which have focused on diverse diseases, including cardiac or pulmonary diseases,
in addition to abdominal diseases, and in various age groups. Additionally, many reports have
evaluated diagnoses made using low dose CT in adults and adolescents, and these findings have
been applied in clinical practice. However, no studies have reported the efficacy of using dose CT
in the diagnosis of acute appendicitis in children younger than 10 years, including those in early
childhood, as previous studies have focused mainly on young adults or adolescents.
Therefore, in the present study, the authors assessed the usefulness and accuracy of low dose CT
for diagnosing acute appendicitis in children, and compared the use of low dose CT in this context
with abdominal USG and standard dose abdominal CT.
Foreground Question
Is low dose CT is more accurate than abdominal USG for diagnosing acute appendicitis in
children?
PICO
Population
Intervention
Comparison
Outcomes
: Patients children who were examined for acute appendicitis
: Diagnostic test for acute appendicities in children with low dose CT
: Diagnostic test for acute appendicitis in children with abdominal USG
: Low dose CT is more accurate when compared with USG and be an
alternative modality to standard CT for assesing pediatric patients
suspected of having acute appendicitis.
Search and selection strategy
Database
:PubMed and Cochrane
Keywords
: “appendicitis” OR “appendicitis childhood” AND “diagnosis” OR “computed
tomography” OR “ultrasonography” OR “comparative”
Limitations
: 5 years publication, Free full text available
Hits
: 62
Table 1: Search Strategy
Database
Search strategy (15-20 December 2020)
Hits
Selected
PubMed
(“Appendicitis”) AND (“childhood” OR “diagnosis” OR
“computed tomography” OR “ultrasonography OR
“comparative”)
53
1
Cochrane
(“Appendicitis”) AND (“childhood” OR “diagnosis” OR
“computed tomography” OR “ultrasonography OR
“comparative”)
7
0
Flowchart
“Appendicitis”
AND
“childhood” OR
“computed tomography”
OR “ultrasonography”
OR “diagnosis” OR
“comparative”
Limits to: 5 years
Pubmed
53
Cochrane
9
Inclusion criteria:
- Free full text is available
Exclusion criteria:
- Inappropriate topic
- Non-data based papers (eg. reviews,
topic discussions, etc)
Screening title / abstract, useful articles:
Pubmed
10
Cochrane
0
Screening abstracts, useful articles:
Pubmed
2
Cochrane
0
Reading full-text, useful articles:
Pubmed
1
Cochrane
0
Chosen article title
Accuracy of low dose CT in the diagnosis of appendicitis in childhood and comparison with
USG and standard dose CT
Journal Review :
Accuracy of low dose CT in the diagnosis of appendicitis in childhood and comparison with
USG and standard dose CT
Abstract
Background: Computed tomography should be performed after careful consideration due to
radiation hazard, which is why interest in low dose CT has increased recently in acute appendicitis.
Previous studies have been performed in adult and adolescents populations, but no studies have
reported on the efficacy of using low dose CT in children younger than 10 years.
Methods: Patients (n = 475) younger than 10 years who were examined for acute appendicitis
were recruited. Subjects were divided into three groups according to the examinations performed:
low dose CT, ultrasonography, and standard dose CT. Subjects were categorized according to age
and body mass index (BMI).
Results: Low-dose CT was a contributive tool in diagnosing appendicitis, and it was an adequate
method, when compared with ultrasonography and standard dose CT in terms of sensitivity (95.5%
vs. 95.0% and 94.5%, p = 0.794), specificity (94.9% vs. 80.0% and 98.8%, p = 0.024), positive
predictive value (96.4% vs. 92.7% and 97.2%, p = 0.019), and negative predictive value (93.7%
vs. 85.7% and 91.3%, p = 0.890). Low dose CT accurately diagnosed patients with a perforated
appendix. Acute appendicitis was effectively diagnosed using low dose CT in both early and
middle childhood. BMI did not influence the accuracy of detecting acute appendicitis on low dose
CT.
Conclusion: Low dose CT is effective and accurate for diagnosing acute appendicitis in childhood,
as well as in adolescents and young adults. Additionally, low dose CT was relatively accurate,
irrespective of age or BMI, for detecting acute appendicitis. Therefore, low dose CT is
recommended for assessing children with suspected acute appendicitis.
Results
(Yong et al., 2017)
To assessed the usefulness and accuracy of low dose CT for
Research questions of the
diagnosing acute appendicitis in children, and compared with
study
abdominal USG and standard dose abdominal CT.
Study design
An observational, analytical and comparative study
Participants
Patients (n = 475) younger than 10 years who were examined for acute
appendicitis
Interventions
For all study subjects, low dose and standard dose CT and abdominal USG
were performed and read by expert abdominal radiologists when they
presented with acute symptoms. Other expert abdominal radiologists
retrospectively reviewed the radiologic images.
Low dose CT
CT was not performed using a certain pre-determined dose; rather, the dose
was determined by age and weight, the radiation dose was actually lower by
approximately 64.2% in the low dose CT group.
Abdominal USG
unclear
Outcome measurements
Depending on the age group and age specific BMI, low dose is more
accurate to help diagnosis appendicitis acute.
Results
Low dose CT was a contributive tool in diagnosing appendicitis, and it was
an adequate method, when compared with ultrasonography and standard
dose CT in terms of sensitivity (95.5% vs. 95.0% and 94.5%, p = 0.794),
specificity (94.9% vs. 80.0% and 98.8%, p = 0.024), positive predictive
value (96.4% vs. 92.7% and 97.2%, p = 0.019), and negative predictive
value (93.7% vs. 85.7% and 91.3%, p = 0.890). Low dose CT accurately
diagnosed patients with a perforated appendix. Acute appendicitis was
effectively diagnosed using low dose CT in both early and middle
childhood. BMI did not influence the accuracy of detecting acute
appendicitis on low dose CT.
Length of follow up
unclear
Loss of follow up
141/616 or 22,8%
Risk of bias: Allocation
concealment
No, because there is exclusion criteria for this study.
Critical Appraisal
VALIDITY
1. Was the diagnostic test evaluated in a Representative spectrum of patients (like those in
whom it would be used in practice?
Yes, all the patients under 10 years of age with clinical suspicion of acute appendicitis.
For the exclusion criteria: Patients who did not undergo radiological evaluation and the
purpose of radiological evaluation was unclear, patients with prior appendectomy, patients
with a gastrointestinal anomaly and abnormalities and patients diagnosed with CT imaging
but the accurate radiation dose was not recorded.
And were divided into two groups: early childhood (2-5 years) and middle childhood (6-10
years)
2. Was the reference standard applied regardless of the index test result?
No, in this study childen who underwent double test (CT after USG) were excluded
3. Was there an independent, blind comparison between the index test and an appropriate
reference (‘gold’) standard of diagnosis?
Unclear, for all study subjects were performed and read by expert abdominal radiologists. But
it did not informed if it is the same person or not.
IMPORTANCE
Are test characteristic presented?
In this journal it is found that:
In Early childhood patients:
Low Dose CT
Sensitivity: 100%, it means 0 patients (0%) with appendicitis acute were falsely identified as
not having it.
Specifity: 96.4%, it means 1 patient (3.6%) without appendicitis acute were falsely identified
as having it.
PPV: 96.8%, it means 1 patient (5.9%) with positive results will not have appendicitis acute.
NPV: 100%, it means 0 patients (0%) with negative results will actually have appendicitis
acute.
Likelihood Ratio
LR (+) = sensitifity / (1-specifity) = 1 / (1-0,96) = 1 / 0,04 = 25
LR (-) = (1-sensitivity) / specifity = (1-1) / 0,96 = 0 / 0,96 = 0
Abdominal USG
Sensitivity: 100%, it means 0 patients (0%) with appendicitis acute were falsely identified as
not having it.
Specifity: 100%, it means 0 patient (0%) without appendicitis acute were falsely identified as
having it.
PPV: 100%, it means 0 patient (0%) with positive results will not have appendicitis acute.
NPV: 100%, it means 0 patients (0%) with negative results will actually have appendicitis
acute.
Likelihood Ratio
LR (+) = sensitifity / (1-specifity) = 1 / (1-0) = 1 / 1 = 1
LR (-) = (1-sensitivity) / specifity = (1-0) / 1 = 1 / 1 = 1
In Middle childhood patients:
Low Dose CT
Sensitivity: 94.8%, it means 5 patients (5.2%) with appendicitis acute were falsely identified
as not having it.
Specifity: 94%, it means 3 patients (4%) with appendicitis acute were falsely identified as
having it.
PPV: 96.8%, it means 3 patients (3.2%) with positive results will not have appendicitis acute.
NPV: 90.4%, it means 5 patients (9.6%) with negative results will actually have appendicitis
acute.
Likelihood Ratio:
LR (+) = sensitivity / (1-specifity) = 0,94 / (1-0,94) = 0,94 / 0,06 = 15,67
LR (-) = (1-sensitivity) / specifity = (1-0,94) / 0,94) = 0,06 / 0,94 = 0,06
Abdominal USG
Sensitivity: 92.6%, it means 2 patients (7.4%) with appendicitis acute were falsely identified
as not having it.
Specifity: 78.6%, it means 3 patients (21.4%) with appendicitis acute were falsely identified
as having it.
PPV: 89.3%, it means 3 patients (10.7%) with positive results will not have appendicitis
acute.
NPV: 84.6%, it means 2 patients (15.4%) with negative results will actually have appendicitis
acute.
Likelihood Ratio:
LR (+) = sensitivity / (1-specifity) = 0,92 / (1-0,78) = 0,94 / 0,22 = 4.27
LR (-) = (1-sensitivity) / specifity = (1-0,92) / 0,78) = 0,08 / 0,78 = 0,10
APPLICABILITY
a. Available
Yes , there are many reports have evaluated diagnoses made using low dose CT.
In indonesia it is available using low dose CT because there are already reports made but the
problem is it is only available in hospital with advance service.
b. Affordable
Unclear, in this study there is no information for the cost of using CT Scan, but in indonesia
using diagnostic test CT Scan can be paid by BPJS.
c. Accurate
Yes, Low dose CT accurate for diagnosing accute appendicitis in childhood
d. Precise
In this study, low dose CT have a high sensitivity and specifity more than USG so safe to say
low dose CT is more accurate for diagnosing appendicitis acute in childhood.
What benefits does this patient can obtained by using diagnostic test low dose CT?
In this study, low dose CT can diagnosing accute appendicitis more accurately than USG in
children under 10 years old with clinical suspicion of accute appendicitis, because USG accuracy
varies, depending on the operator. So in this case, low dose CT can safely be used for diagnosing
accute appendicitis.
Bibliographies
Yi DY, Lee KH, Park SB, Kim JT, Lee NM, Kim H, et al. Accuracy of low dose CT in the
diagnosis of appendicitis in childhood and comparison with USG and standard dose CT. J
Pediatr (Rio J). 2017;93:625---31.
Study, D. and Worksheet, A. (2010) ‘Step 1 : Are the results of the study valid ? Was the
diagnostic test evaluated in a Representative spectrum of patients ( like those in whom it would
be used in practice )? Was the reference standard applied regardless of the index test result ? Was
there an independent , blind comparison between the index test and an appropriate reference ('
gold ’) standard of diagnosis ? Step 2 : What were the results ? Step 3 : Applicability of the
results Were the methods for performing the test described in sufficient detail to permit
replication ?’, pp. 1–3.
