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Sonography of suspected acute appendicitis in children: Evaluation of the progress in performance of senior residents
Journal of Pediatric Surgery xxx (2017) xxx–xxx
Contents lists available at ScienceDirect
Journal of Pediatric Surgery journal homepage: www.elsevier.com/locate/jpedsurg
Clinical Research Paper
Sonography of suspected acute appendicitis in children: Evaluation of the progress in performance of senior residents Pierre Gerbier a, Aurélien Binet b, Mathilde Etancelin a, Emmanuel Barteau a, Marie Auger b, Luciano Morales a, Philippe Bertrand c,d, Dominique Sirinelli a,d, Baptiste Morel a,d,⁎ a
Pediatric Radiology Department, Clocheville Hospital, 49 Boulevard Beranger, 37000, University Hospital Tours, France Surgery Department, Clocheville Hospital, 49 Boulevard Beranger, 37000, University Hospital Tours, France Radiology Department, Bretonneau Hospital, 49 Boulevard Beranger, 37000, University Hospital Tours, France d Faculty of Medicine, Francois Rabelais University, Tours, France b c
a r t i c l e
i n f o
Article history: Received 22 March 2017 Received in revised form 9 May 2017 Accepted 11 May 2017 Available online xxxx Key words: Sonography Acute appendicitis Residents Children Pediatric radiology
a b s t r a c t Purpose: The objective of this study was to evaluate the progress in performance of senior residents in diagnosing acute appendicitis. Material and methods: Results were collected and compared of ultrasound examinations performed for suspected acute appendicitis by three senior residents and two faculty members over a six-month period in a university hospital setting. A grid with the sonographic findings was completed separately by the residents and the faculty members immediately after each examination. The duration of each examination was reported. The final ultrasound diagnosis was compared to the surgical and pathological results and to the clinical follow-up. Results: The residents and faculty members performed 171 consecutive ultrasound examinations including 49 children with acute appendicitis and 122 with normal appendices. The accuracy of the diagnosis by the residents was 96%, and was similar to that of the faculty members (kappa=0.90) over the six months. The duration of the resident ultrasound examinations was significantly shorter during the second three-month period (p = 0.01). No significant differences in diagnostic accuracy were demonstrated by the residents between the first and second three-month periods (p = 0.06). Conclusions: The residents performed well when using sonography to diagnose acute appendicitis in children, and were faster during the second three-month period. Level of evidence: I. © 2017 Elsevier Inc. All rights reserved.
Acute abdominal pain is a common cause for consultation in pediatric diagnostic imaging [1,2]. Approximately a third of children presenting with acute abdominal pain have appendicitis [3], making this affliction the first cause of abdominal surgery in children [4]. Despite a declining number of appendectomies in our country, decreasing from approximately 300,000 cases during the 1990s to 83,000 in 2011, the number of appendectomies still remains rather high compared to the other Organization for Economic Co-operation and Development (OECD) countries, and is partially explained by the resection of a considerable number of healthy appendices [5]. Indeed, the diagnosis of appendicitis in a child can be difficult, with a considerable proportion of diagnostic errors based on the clinical and laboratory data. The symptoms and clinical signs of acute appendicitis are not specific, which can lead to frequent requests for diagnostic imaging. This constitutes a challenge for pediatric radiologists. Ultrasound is regarded, by the ⁎ Corresponding author at: Pediatric Radiology Department, Clocheville University Hospital, 49 Boulevard Beranger, 37000 Tours, France. Tel.: +33 2 47 4747 58; fax: +33 2 47 4786 90. E-mail address: [email protected] (B. Morel).
American College of Radiology (ACR), as the method best suited for initially imaging a patient with suspected acute appendicitis [6]. Ultrasound is efficacious, because of its lack of ionizing radiation, highsensitivity [3,7], and low-cost [8]. The wide range of reported sensitivity and specificity in the ultrasound diagnosis of acute appendicitis in children appears to be because of operator and patient factors [1,3]. Obesity has been cited as a factor responsible for a significant decrease in the effectiveness of ultrasound [9]. Several authors report poor diagnostic results in acute appendicitis when the ultrasound is performed by an operator with little experience in pediatric ultrasound [1,10]. The objective of our study was to prospectively evaluate the progress in performance of senior residents in diagnosing acute appendicitis.
1. Materials and methods 1.1. Patient population We obtained approval by the local Ethics Committee. All patients gave their informed consent. Between November 2015 and April 2016,
http://dx.doi.org/10.1016/j.jpedsurg.2017.05.013 0022-3468/© 2017 Elsevier Inc. All rights reserved.
Please cite this article as: Gerbier P, et al, Sonography of suspected acute appendicitis in children: Evaluation of the progress in performance of senior residents, J Pediatr Surg (2017), http://dx.doi.org/10.1016/j.jpedsurg.2017.05.013
2
P. Gerbier et al. / Journal of Pediatric Surgery xxx (2017) xxx–xxx
we collected and analyzed prospectively the demographic data and results of ultrasound examinations performed for suspected acute appendicitis by three senior residents in radiology and by two faculty members in a university hospital setting. Senior residents were in their fifth year of training. They had the same general adult radiological training course, including standard radiography, general ultrasound, CT and MRI scans. They did not have experiences in pediatric radiology. Faculty members were exclusively pediatric radiologists, with respectively 4 and more than 30 years of experience. All patients were less than 16 years of age, were examined during regular daytime hours (from 8 a.m. to 7 p.m.), and were referred for suspected acute appendicitis either from the hospital emergency department or from practitioners in the community. 1.2. Sonographic examinations Ultrasounds were carried out on two ultrasound devices GElogicE9 with a convex probe 2–9 Hz and a high frequency linear probe (9 Hz). An initial ultrasound was performed by one of the three senior residents in diagnostic and interventional imaging. This examination included the entire abdomen and pelvis. Immediately after the senior resident, a second ultrasound was carried out by a faculty member, in the same room with identical equipment, without knowledge of the resident's results. A grid with the sonographic findings was completed separately by the residents and the faculty members immediately after each examination. Then, the senior resident and the faculty member shared their interpretation and a final consensual radiological report was given to the clinician. The duration of each resident and faculty member examinations was tabulated. An initial ultrasound was performed by one of the three senior residents in diagnostic and interventional imaging. This examination included the entire abdomen and pelvis. Then, a second ultrasound was carried out by a faculty member, without knowledge of the resident's results. A grid with the sonographic findings was completed separately by the residents and the faculty members immediately after each examination. The duration of each resident and faculty member examinations was tabulated. 1.2.1. Grid and diagnostic categorization The ultrasound elements included the visualization of the appendix (non-visualization, partial or complete visualization), the transverse diameter of the appendix (less than 6 mm, between 6 and 8 mm, greater than 8 mm); the wall's differentiation (preserved or not, Fig. 1), localized tenderness and guarding, infiltration of the periappendiceal fat (Fig. 1), regional lymphadenopathy, and free intraperitoneal fluid. We also recorded complications such as a periappendiceal mass or abscess. At the end of the procedure, depending on the previous ultrasound criteria, four diagnostic conclusions were possible: acute appendicitis, likely appendicitis, appendicitis unlikely, or normal appendix. Acute appendicitis was diagnosed when an appendix was enlarged, wall differentiation was not preserved, associated localized tenderness was seen and infiltration of the periappendiceal fat was observed. A normal appendix was diagnosed when a normal-sized appendix with preserved wall differentiation, and no infiltration of the periappendiceal fat were observed. In case of non-visualization of the appendix, when all indirect ultrasonographic appendicitis signs were absent, the radiologists have considered that the diagnosis of appendicitis was unlikely. In the opposite case, the radiologists concluded probable appendicitis. 1.3. Follow-up of the patients The final ultrasound diagnosis was correlated with the surgical and pathological results and with clinical follow-up. The decision of the surgeons to operate depended mainly on the clinical and ultrasonographical data, and biological data when available. The operative report was available 48 h later, allowing prompt radiological-surgical
Fig. 1. Transversal slice of an acute appendicitis, showing an increase of size of appendix with a wall's dedifferentiation (white arrow), associated with an infiltration of the periappendiceal fat (white arrowhead).
correlation and feedback to improve resident performance. Once the children were back at home with discharge instructions, the patient's medical record was consulted two weeks after discharge, noting any readmission to the emergency department. In cases where the appendix had not been visualized by ultrasound, the families were contacted by phone three months after their hospitalization to verify that no appendectomy had been performed at another medical center in the interval. 1.4. Statistical analysis To evaluate interobserver agreement between residents and faculty members, we assigned a letter to the final ultrasound diagnosis: acute appendicitis = A, probable appendicitis = B, appendicitis unlikely = C and normal appendix = D. A binary classification was used: a positive response (sum of the final ultrasound diagnosis: acute appendicitis, A; and probable appendicitis, B) or a negative response (sum of the final ultrasound diagnosis: appendicitis unlikely, C; and normal appendix, D). Interobserver agreements between resident and faculty members for positive and negative diagnosis were calculated. 1.4.1. Diagnostic errors, false positives, and false negatives An imaging result was considered false positive when the final ultrasound classification was acute appendicitis (A) or probable appendicitis (B) but the appendix was healthy at surgery, a complementary examination such as computed tomography (CT) was unremarkable, or if the patient had returned home and was symptom-free for fifteen days following the ultrasound. A result was considered false negative when the final sonographic classification was normal appendix or appendicitis unlikely, but a diagnosis of acute appendicitis was established by pathological means. 1.4.2. Descriptive statistics We calculated the sensitivity, specificity, positive predictive value, negative predictive value, exactitude and confidence intervals for the residents and the faculty members. These calculations were made over the course of the six-month study period and during the first and the second three-month periods by comparing the sonographic results with a gold standard. The gold standard was defined as the pathological diagnosis for the patients treated surgically or the long-term clinical follow-up for the non-operated group. Statistical analyses were performed using the software R version 3.3.1 [11]. A p-value b 0.05 was considered significant. The McNemar test and Kappa coefficient were used to measure interobserver agreement. A Student t test was used to compare duration of examination.
Please cite this article as: Gerbier P, et al, Sonography of suspected acute appendicitis in children: Evaluation of the progress in performance of senior residents, J Pediatr Surg (2017), http://dx.doi.org/10.1016/j.jpedsurg.2017.05.013
P. Gerbier et al. / Journal of Pediatric Surgery xxx (2017) xxx–xxx
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Percentage of visualization of the appendix
100% 90% 80% 70% 60%
faculty members
50% 40%
senior residents
30% 20% 10% 0%
SIx months period, intervalls of 15 days Fig. 2. Percentage of visualization of the appendix by the residents and faculty members during the six months' period study.
2. Results 2.1. Population
having a healthy appendix, 3 false positive (2.4%) had been diagnosed by the residents and 2 false positive (1.6%) by the faculty members as having appendicitis, including one shared with the resident.
All children with suspected appendicitis agreed to be in the study and had an ultrasonographic examination. During the six-month study period, 171 patients were included: 81 (47.4%) girls and 90 (52.6%) boys. The median age was 9.9 years, with a range of 2 to 15 years. The mean weight for both genders was 35.9 kg, the median weight was 34 kg, with extremes of 11 and 74 kg.
2.2.3. Duration of the sonographic examination In case of acute appendicitis, the resident performed in 8 min and 58 s, whereas in case of normal appendix in 11 min and 22 s. The mean duration of the resident ultrasound examination was significantly shorter during the second three months' period (11 min 52 versus 9 min 27, p = 0.01). The faculty members performed in 2 min and 3 s.
2.2. Sonographic examinations
2.2.4. Diagnostic agreement During the six-month study interval, the residents and faculty members examined successively 171 patients, 89 during the first three months and 82 during the second three months. The agreement of the positive and negative diagnoses was 163/171 (Kappa = 0.89) over the entire six-month period of study. The agreement was 84/89 cases (Kappa = 0.85) in the first three months and 79/82 (Kappa = 0.96) during the second three months. There were 8 instances of diagnostic discordance between the residents and faculty: 5 during the first three months and 3 during the second three months. The exactitude of the diagnosis of the residents was 95.9% (91.8–98; Kappa = 0.90) over the six months, 95.5% (89–98.2; Kappa = 0.88) during the first 3 months and 96.3% (89.8–98.7) (Kappa = 0.92) during the second three months. The sensitivity and the specificity of the residents over the entire six months were, respectively, 91% (80.8–96.8) and 97% (93–99.2). For the first three months, they were, respectively, 90.9 (72.2–97.5) and 97% (89.7–99.2) and 92.6% (76.6–97.9) and 98.2% (90.4–99.7) for the second three months. We did not observe a significant change in the diagnostic accuracy of the residents during the six-month study period (p = 0.06). The faculty members achieved a sensitivity and a specificity during the study period of, respectively, 100% (92.7–100) and 98.3% (94.2–99.5; Kappa = 0.9), and the exactitude of the diagnosis was 98.8% (95.8–99.7).
2.2.1. Sonographic visualization of the appendix The residents visualized the appendix in 118 of the 171 patients (69%), including 78 completely visualized (46%) and 40 partially visualized (23%) (Fig. 2). The appendix was not identified in 53 patients (31%). The faculty members visualized the appendix in 138 cases (81%), including 105 completely visualized (61.4%) and 33 partially visualized (19.33%). The appendix could not be identified in 33 cases (19.3%). The proportions of visualized appendices as well as completely visualized appendices were significantly higher for faculty members than for residents (p = 0.003). 2.2.2. Appendicitis Of the 171 patients studied, 49 had appendicitis, confirmed by pathological analysis, and 122 did not have appendicitis, one of which was confirmed normal at surgery (a 15 years old girl with recurrent right abdominal pain had two ultrasound diagnoses of “appendicitis unlikely” within one week. She finally underwent a laparoscopic operation. An appendix with acute mucosal inflammation in retrocecal position was found.) Senior residents and faculty member have diagnosed 9 complicated appendicitis (2 perforations and 7 abscess) confirmed by surgical and pathological results. In two cases, appendix was not identified during ultrasound examination and CT scan was performed before discharge from the hospital. The two CT scans were interpreted as normal. The other patients were sent home and did not need a followup consultation during the fifteen days that followed the ultrasound. All positive US patients were operated. Surgeons have decided to operate depending mainly on the clinical and ultrasonographical data, and biological data when available. Of the 49 patients with a definite diagnosis of acute appendicitis, 4 (8.1%) were considered as negative by the resident (false negative). One false-positive diagnosis (2%) by ultrasound of appendicitis resulted in an appendectomy. Of the 122 patients
2.2.5. Degree of diagnostic certainty At the completion of each questionnaire, one of four possible diagnoses was chosen: acute appendicitis (A), probable appendicitis (B), appendicitis unlikely (C) and normal appendix (D). In those cases where the diagnoses of both residents and faculty members agreed for acute appendicitis (A) or normal appendix (D), the diagnoses were considered correct. Detailed data are in the Table 1. For the residents, 82 (47.9%) ultrasounds had a diagnosis with a high degree of confidence
Please cite this article as: Gerbier P, et al, Sonography of suspected acute appendicitis in children: Evaluation of the progress in performance of senior residents, J Pediatr Surg (2017), http://dx.doi.org/10.1016/j.jpedsurg.2017.05.013
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P. Gerbier et al. / Journal of Pediatric Surgery xxx (2017) xxx–xxx
Table 1 Percentages of visualization of the appendix, degree of diagnostic certainty and diagnosis. Visualization of the appendix
Senior residents Faculty members
Degree of diagnostic certainty
Diagnosis
Complete visualization
Partial visualization
Non-visualization
Complete visualization
Partial visualization
Non-visualization
Acute appendicitis (A)
Probable appendicitis (B)
Appendicitis unlikely (C)
Normal appendix (D)
78 (45.6%) 105 (61.4%)
40 (23.4%) 33 (19.3%)
53 (31%) 33 (19.3%)
69 (88%) 94 (90%)
13 (33%) 11 (33%)
0 0
35 (20.5%) 40 (23.4%)
13 (7.6%) 11 (6.4%)
76 (44.4%) 55 (32.2%)
47 (27.5%) 65 (38%)
(i.e. diagnosis A or D), for the faculty members, 105 (61.4%). When the appendix was completely visualized, the degree of confidence was 88% for the residents and 90% for the faculty members. With partial visualization of the appendix, the degree of confidence was 33% for both the residents and faculty members. When the appendix could not be identified, the degree of confidence was zero. 3. Discussion Our results have confirmed good diagnostic performance by the residents during the six-month study period. The values for sensitivity (0.92), specificity (0.97), and accuracy (0.96) we obtained for the residents are similar to those reported in meta-analyses [3,12]. We also observed no statistically significant difference between the diagnostic performance achieved by the residents and that of the faculty members. However, we have noticed that the mean duration of ultrasound examination was significantly shorter during the second three-month period. Our study is consistent with an enhanced medical learning cycle that should be “see many, learn from the outcome, do many with supervision and learn from the outcome, and finally teach many with supervision and learn from the outcome.” described by Rohrich [13], which is a new version of the Halsted's model of “see one, do one, teach one.” It emphasizes the capacity of senior residents to be efficient in the ultrasound diagnosis of appendicitis and a progression of their ability during their training. It also provides pedagogical information concerning the utility of a radiological grid with objectives structures to analyze and prompt feedback between surgeons and radiologists. Finally, it also suggests that senior residents had as good ultrasonographic diagnostic skills, as faculty members in the majority of cases. Contributory factors are ultrasound as first imaging procedure for pediatric appendicitis, with a systematic completion of a grid with the sonographic findings and a feedback with radiological-surgical correlation. One falsepositive case of appendicitis was misdiagnosed because of an increase size of the appendix (7 mm). It highlights that the customary upper normal value of 6 mm is probably too sensitive [14]. During our study, the residents had also four false-negative examinations, all corrected by a faculty member upon the subsequent repeat examination. Among these four patients, the appendix was either not visualized at all (1) or only partially visualized (3), but was completely visualized by the faculty radiologist in all four cases, emphasizing the importance of visualization of the appendix by sonography. Secondary signs may also improve the diagnostic accuracy of equivocal ultrasounds for suspected appendicitis in children [15]. In our study, the faculty members were more successful than the residents at visualizing the appendix. The rate of visualization of the appendix by ultrasound has varied widely in the literature. Lee et al. recorded a rate of visualization of the appendix of 99% among patients in all age groups, utilizing a classical approach in the supine position with posterior manual compression [16]. However, this result has not been reproduced by other investigators. Binkovitz et al. visualized the appendix in 49% of cases [17] and did not observe significant differences as a function of patient age, gender, or body mass index (BMI). As in our study, visualization was more frequent in acute appendicitis (75%) than when the appendix was healthy (34%) (p = 0.0001). Moreover, they described an increase in the rate of visualization of the
appendix during the study of 32% the first year of training for the residents with 50.6% the fifth year. Mittal et al. have found a lower rate of visualization of the appendix in the hospitals where ultrasound is used less often or is less available as the first-line imaging examination (25%) compared to hospitals where ultrasound is always available and is routinely employed as the first imaging procedure (56%) [1]. Several authors have shown that specialized pediatric sonographers identified the appendix more often than the general sonographer [10,17]. These reports confirm the importance of experience and the progression of technical competence in sonography that occurs during the course of resident training. In this study, rates of visualization of the appendix were higher than those reported in the majority of the North-American studies. These results could be explained by the fact that ultrasound was performed in a different population by pediatric radiologists, and by residents spending an entire six-month rotation performing only pediatric imaging. That is, the improved performance was partially because of a higher level of medical expertise. Pohl et al. have shown that ultrasound examinations carried out by a sonographer alone had a sensitivity of 26%, compared to 61% for those performed by a sonographer supervised by a radiologist, when diagnosing acute appendicitis in a mixed population of adults and children. They stressed the importance of supervision by an experienced operator [18]. The lack of significant progress of the residents during their six-month rotation could be explained by their already high level of competence with ultrasound in adult patients and, since they were approaching the end of their residency, by their experience in independent diagnostic decision-making. Complicated appendicitis would probably have not influenced the results. Senior residents and faculty members always worked in the same conditions when performing ultrasonographic examinations. The ultrasound grid contained criteria about complicated appendicitis that should always be looked for. It is possible that, with a larger number of study subjects, we might have observed a significant difference in performance between the residents and faculty members, since the latter were more successful in visualizing the appendix in its entirety. The real conditions of training during the residency and the number of patients included over a sixmonth period and during routine working hours constituted limitations to our study. However, if we had included patients over different semesters with different groups of residents we would have encountered greater disparity in the level of competence between inexperienced residents and those nearing the end of their training. We looked for an evaluation of the performance of senior residents, which will work soon independently. It is important to note that the residents in this study have six continuous months of specialized training in pediatric radiology. This is not the case in some other countries where training is limited to three or four fragmented months spread over their entire resident training. 4. Conclusion The sonographic evaluation of suspected acute appendicitis in children, performed by radiology residents nearing the end of their training, was as reliable as that of experienced pediatric radiologist,
Please cite this article as: Gerbier P, et al, Sonography of suspected acute appendicitis in children: Evaluation of the progress in performance of senior residents, J Pediatr Surg (2017), http://dx.doi.org/10.1016/j.jpedsurg.2017.05.013
P. Gerbier et al. / Journal of Pediatric Surgery xxx (2017) xxx–xxx
with significant shorter examination during the second three months' period. Ultrasound as first-line imaging for suspected pediatric appendicitis associated with a systematic completion of a grid with the sonographic findings and prompt radiological-surgical correlation could help to improve resident performance. Acknowledgements The authors thank Kris Munroe, John C. Scatarige and John Sheath for English language assistance and their friendly support. References [1] Mittal MK, Dayan PS, Macias CG, et al. Performance of ultrasound in the diagnosis of appendicitis in children in a multicenter cohort. Acad Emerg Med 2013;20:697–702. http://dx.doi.org/10.1111/acem.12161. [2] Saucier A, Huang EY, Emeremni CA, et al. Prospective evaluation of a clinical pathway for suspected appendicitis. Pediatrics 2014;133:e88–95. http://dx.doi.org/10. 1542/peds.2013-2208. [3] Doria AS, Moineddin R, Kellenberger CJ, et al. US or CT for diagnosis of appendicitis in children and adults? A meta-analysis. Radiology 2006;241:83–94. http://dx.doi.org/ 10.1148/radiol.2411050913. [4] Sømme S, Bronsert M, Morrato E, et al. Frequency and variety of inpatient pediatric surgical procedures in the United States. Pediatrics 2013;132:e1466–72. http://dx. doi.org/10.1542/peds.2013-1243. [5] Gracey D, McClure MJ. The impact of ultrasound in suspected acute appendicitis. Clin Radiol 2007;62:573–8. http://dx.doi.org/10.1016/j.crad.2006.12.008. [6] Rosen MP, Ding A, Blake MA, et al. ACR Appropriateness Criteria® right lower quadrant pain–suspected appendicitis. J Am Coll Radiol 2011;8:749–55. http://dx.doi.org/ 10.1016/j.jacr.2011.07.010.
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[7] Cundy TP, Gent R, Frauenfelder C, et al. Benchmarking the value of ultrasound for acute appendicitis in children. J Pediatr Surg 2016;51:1939–43. http://dx.doi.org/ 10.1016/j.jpedsurg.2016.09.009. [8] Tiu C-M, Chou Y-H, Chen J-D, et al. Ultrasound diagnosis of acute appendicitis: impact on cost and outcome in pediatric patients. J Med Ultrasound 2004;12:69–74. http://dx.doi.org/10.1016/S0929-6441(09)60067-9. [9] Schuh S, Man C, Cheng A, et al. Predictors of non-diagnostic ultrasound scanning in children with suspected appendicitis. J Pediatr 2011;158:112–8. http://dx.doi.org/ 10.1016/j.jpeds.2010.07.035. [10] Trout AT, Sanchez R, Ladino-Torres MF, et al. A critical evaluation of US for the diagnosis of pediatric acute appendicitis in a real-life setting: how can we improve the diagnostic value of sonography? Pediatr Radiol 2012;42:813–23. http://dx.doi.org/ 10.1007/s00247-012-2358-6. [11] Team RC. R: A language and environment for statistical computing; 2014[Vienna, Austria. URL: http://www.R-project.org/ 2015]. [12] Brennan GDG. Pediatric appendicitis: pathophysiology and appropriate use of diagnostic imaging. CJEM 2006;8:425–32. [13] Rohrich RJ. “See one, do one, teach one”: an old adage with a new twist. Plast Reconstr Surg 2006;118:257–8. http://dx.doi.org/10.1097/01.prs.0000233177. 97881.85. [14] Telesmanich ME, Orth RC, Zhang W, et al. Searching for certainty: findings predictive of appendicitis in equivocal ultrasound exams. Pediatr Radiol 2016;46:1539–45. http://dx.doi.org/10.1007/s00247-016-3645-4. [15] Partain KN, Patel A, Travers C, et al. Secondary signs may improve the diagnostic accuracy of equivocal ultrasounds for suspected appendicitis in children. J Pediatr Surg 2016. http://dx.doi.org/10.1016/j.jpedsurg.2016.03.005. [16] Lee JH, Jeong YK, Park KB, et al. Operator-dependent techniques for graded compression sonography to detect the appendix and diagnose acute appendicitis. AJR Am J Roentgenol 2005;184:91–7. http://dx.doi.org/10.2214/ajr.184.1.01840091. [17] Binkovitz LA, Unsdorfer KML, Thapa P, et al. Pediatric appendiceal ultrasound: accuracy, determinacy and clinical outcomes. Pediatr Radiol 2015;45:1934–44. http://dx. doi.org/10.1007/s00247-015-3432-7. [18] Pohl D, Golub R, Schwartz GE, et al. Appendiceal ultrasonography performed by nonradiologists: does it help in the diagnostic process? J Ultrasound Med 1998; 17:217–21.
Please cite this article as: Gerbier P, et al, Sonography of suspected acute appendicitis in children: Evaluation of the progress in performance of senior residents, J Pediatr Surg (2017), http://dx.doi.org/10.1016/j.jpedsurg.2017.05.013
Contents lists available at ScienceDirect
Journal of Pediatric Surgery journal homepage: www.elsevier.com/locate/jpedsurg
Clinical Research Paper
Sonography of suspected acute appendicitis in children: Evaluation of the progress in performance of senior residents Pierre Gerbier a, Aurélien Binet b, Mathilde Etancelin a, Emmanuel Barteau a, Marie Auger b, Luciano Morales a, Philippe Bertrand c,d, Dominique Sirinelli a,d, Baptiste Morel a,d,⁎ a
Pediatric Radiology Department, Clocheville Hospital, 49 Boulevard Beranger, 37000, University Hospital Tours, France Surgery Department, Clocheville Hospital, 49 Boulevard Beranger, 37000, University Hospital Tours, France Radiology Department, Bretonneau Hospital, 49 Boulevard Beranger, 37000, University Hospital Tours, France d Faculty of Medicine, Francois Rabelais University, Tours, France b c
a r t i c l e
i n f o
Article history: Received 22 March 2017 Received in revised form 9 May 2017 Accepted 11 May 2017 Available online xxxx Key words: Sonography Acute appendicitis Residents Children Pediatric radiology
a b s t r a c t Purpose: The objective of this study was to evaluate the progress in performance of senior residents in diagnosing acute appendicitis. Material and methods: Results were collected and compared of ultrasound examinations performed for suspected acute appendicitis by three senior residents and two faculty members over a six-month period in a university hospital setting. A grid with the sonographic findings was completed separately by the residents and the faculty members immediately after each examination. The duration of each examination was reported. The final ultrasound diagnosis was compared to the surgical and pathological results and to the clinical follow-up. Results: The residents and faculty members performed 171 consecutive ultrasound examinations including 49 children with acute appendicitis and 122 with normal appendices. The accuracy of the diagnosis by the residents was 96%, and was similar to that of the faculty members (kappa=0.90) over the six months. The duration of the resident ultrasound examinations was significantly shorter during the second three-month period (p = 0.01). No significant differences in diagnostic accuracy were demonstrated by the residents between the first and second three-month periods (p = 0.06). Conclusions: The residents performed well when using sonography to diagnose acute appendicitis in children, and were faster during the second three-month period. Level of evidence: I. © 2017 Elsevier Inc. All rights reserved.
Acute abdominal pain is a common cause for consultation in pediatric diagnostic imaging [1,2]. Approximately a third of children presenting with acute abdominal pain have appendicitis [3], making this affliction the first cause of abdominal surgery in children [4]. Despite a declining number of appendectomies in our country, decreasing from approximately 300,000 cases during the 1990s to 83,000 in 2011, the number of appendectomies still remains rather high compared to the other Organization for Economic Co-operation and Development (OECD) countries, and is partially explained by the resection of a considerable number of healthy appendices [5]. Indeed, the diagnosis of appendicitis in a child can be difficult, with a considerable proportion of diagnostic errors based on the clinical and laboratory data. The symptoms and clinical signs of acute appendicitis are not specific, which can lead to frequent requests for diagnostic imaging. This constitutes a challenge for pediatric radiologists. Ultrasound is regarded, by the ⁎ Corresponding author at: Pediatric Radiology Department, Clocheville University Hospital, 49 Boulevard Beranger, 37000 Tours, France. Tel.: +33 2 47 4747 58; fax: +33 2 47 4786 90. E-mail address: [email protected] (B. Morel).
American College of Radiology (ACR), as the method best suited for initially imaging a patient with suspected acute appendicitis [6]. Ultrasound is efficacious, because of its lack of ionizing radiation, highsensitivity [3,7], and low-cost [8]. The wide range of reported sensitivity and specificity in the ultrasound diagnosis of acute appendicitis in children appears to be because of operator and patient factors [1,3]. Obesity has been cited as a factor responsible for a significant decrease in the effectiveness of ultrasound [9]. Several authors report poor diagnostic results in acute appendicitis when the ultrasound is performed by an operator with little experience in pediatric ultrasound [1,10]. The objective of our study was to prospectively evaluate the progress in performance of senior residents in diagnosing acute appendicitis.
1. Materials and methods 1.1. Patient population We obtained approval by the local Ethics Committee. All patients gave their informed consent. Between November 2015 and April 2016,
http://dx.doi.org/10.1016/j.jpedsurg.2017.05.013 0022-3468/© 2017 Elsevier Inc. All rights reserved.
Please cite this article as: Gerbier P, et al, Sonography of suspected acute appendicitis in children: Evaluation of the progress in performance of senior residents, J Pediatr Surg (2017), http://dx.doi.org/10.1016/j.jpedsurg.2017.05.013
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P. Gerbier et al. / Journal of Pediatric Surgery xxx (2017) xxx–xxx
we collected and analyzed prospectively the demographic data and results of ultrasound examinations performed for suspected acute appendicitis by three senior residents in radiology and by two faculty members in a university hospital setting. Senior residents were in their fifth year of training. They had the same general adult radiological training course, including standard radiography, general ultrasound, CT and MRI scans. They did not have experiences in pediatric radiology. Faculty members were exclusively pediatric radiologists, with respectively 4 and more than 30 years of experience. All patients were less than 16 years of age, were examined during regular daytime hours (from 8 a.m. to 7 p.m.), and were referred for suspected acute appendicitis either from the hospital emergency department or from practitioners in the community. 1.2. Sonographic examinations Ultrasounds were carried out on two ultrasound devices GElogicE9 with a convex probe 2–9 Hz and a high frequency linear probe (9 Hz). An initial ultrasound was performed by one of the three senior residents in diagnostic and interventional imaging. This examination included the entire abdomen and pelvis. Immediately after the senior resident, a second ultrasound was carried out by a faculty member, in the same room with identical equipment, without knowledge of the resident's results. A grid with the sonographic findings was completed separately by the residents and the faculty members immediately after each examination. Then, the senior resident and the faculty member shared their interpretation and a final consensual radiological report was given to the clinician. The duration of each resident and faculty member examinations was tabulated. An initial ultrasound was performed by one of the three senior residents in diagnostic and interventional imaging. This examination included the entire abdomen and pelvis. Then, a second ultrasound was carried out by a faculty member, without knowledge of the resident's results. A grid with the sonographic findings was completed separately by the residents and the faculty members immediately after each examination. The duration of each resident and faculty member examinations was tabulated. 1.2.1. Grid and diagnostic categorization The ultrasound elements included the visualization of the appendix (non-visualization, partial or complete visualization), the transverse diameter of the appendix (less than 6 mm, between 6 and 8 mm, greater than 8 mm); the wall's differentiation (preserved or not, Fig. 1), localized tenderness and guarding, infiltration of the periappendiceal fat (Fig. 1), regional lymphadenopathy, and free intraperitoneal fluid. We also recorded complications such as a periappendiceal mass or abscess. At the end of the procedure, depending on the previous ultrasound criteria, four diagnostic conclusions were possible: acute appendicitis, likely appendicitis, appendicitis unlikely, or normal appendix. Acute appendicitis was diagnosed when an appendix was enlarged, wall differentiation was not preserved, associated localized tenderness was seen and infiltration of the periappendiceal fat was observed. A normal appendix was diagnosed when a normal-sized appendix with preserved wall differentiation, and no infiltration of the periappendiceal fat were observed. In case of non-visualization of the appendix, when all indirect ultrasonographic appendicitis signs were absent, the radiologists have considered that the diagnosis of appendicitis was unlikely. In the opposite case, the radiologists concluded probable appendicitis. 1.3. Follow-up of the patients The final ultrasound diagnosis was correlated with the surgical and pathological results and with clinical follow-up. The decision of the surgeons to operate depended mainly on the clinical and ultrasonographical data, and biological data when available. The operative report was available 48 h later, allowing prompt radiological-surgical
Fig. 1. Transversal slice of an acute appendicitis, showing an increase of size of appendix with a wall's dedifferentiation (white arrow), associated with an infiltration of the periappendiceal fat (white arrowhead).
correlation and feedback to improve resident performance. Once the children were back at home with discharge instructions, the patient's medical record was consulted two weeks after discharge, noting any readmission to the emergency department. In cases where the appendix had not been visualized by ultrasound, the families were contacted by phone three months after their hospitalization to verify that no appendectomy had been performed at another medical center in the interval. 1.4. Statistical analysis To evaluate interobserver agreement between residents and faculty members, we assigned a letter to the final ultrasound diagnosis: acute appendicitis = A, probable appendicitis = B, appendicitis unlikely = C and normal appendix = D. A binary classification was used: a positive response (sum of the final ultrasound diagnosis: acute appendicitis, A; and probable appendicitis, B) or a negative response (sum of the final ultrasound diagnosis: appendicitis unlikely, C; and normal appendix, D). Interobserver agreements between resident and faculty members for positive and negative diagnosis were calculated. 1.4.1. Diagnostic errors, false positives, and false negatives An imaging result was considered false positive when the final ultrasound classification was acute appendicitis (A) or probable appendicitis (B) but the appendix was healthy at surgery, a complementary examination such as computed tomography (CT) was unremarkable, or if the patient had returned home and was symptom-free for fifteen days following the ultrasound. A result was considered false negative when the final sonographic classification was normal appendix or appendicitis unlikely, but a diagnosis of acute appendicitis was established by pathological means. 1.4.2. Descriptive statistics We calculated the sensitivity, specificity, positive predictive value, negative predictive value, exactitude and confidence intervals for the residents and the faculty members. These calculations were made over the course of the six-month study period and during the first and the second three-month periods by comparing the sonographic results with a gold standard. The gold standard was defined as the pathological diagnosis for the patients treated surgically or the long-term clinical follow-up for the non-operated group. Statistical analyses were performed using the software R version 3.3.1 [11]. A p-value b 0.05 was considered significant. The McNemar test and Kappa coefficient were used to measure interobserver agreement. A Student t test was used to compare duration of examination.
Please cite this article as: Gerbier P, et al, Sonography of suspected acute appendicitis in children: Evaluation of the progress in performance of senior residents, J Pediatr Surg (2017), http://dx.doi.org/10.1016/j.jpedsurg.2017.05.013
P. Gerbier et al. / Journal of Pediatric Surgery xxx (2017) xxx–xxx
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Percentage of visualization of the appendix
100% 90% 80% 70% 60%
faculty members
50% 40%
senior residents
30% 20% 10% 0%
SIx months period, intervalls of 15 days Fig. 2. Percentage of visualization of the appendix by the residents and faculty members during the six months' period study.
2. Results 2.1. Population
having a healthy appendix, 3 false positive (2.4%) had been diagnosed by the residents and 2 false positive (1.6%) by the faculty members as having appendicitis, including one shared with the resident.
All children with suspected appendicitis agreed to be in the study and had an ultrasonographic examination. During the six-month study period, 171 patients were included: 81 (47.4%) girls and 90 (52.6%) boys. The median age was 9.9 years, with a range of 2 to 15 years. The mean weight for both genders was 35.9 kg, the median weight was 34 kg, with extremes of 11 and 74 kg.
2.2.3. Duration of the sonographic examination In case of acute appendicitis, the resident performed in 8 min and 58 s, whereas in case of normal appendix in 11 min and 22 s. The mean duration of the resident ultrasound examination was significantly shorter during the second three months' period (11 min 52 versus 9 min 27, p = 0.01). The faculty members performed in 2 min and 3 s.
2.2. Sonographic examinations
2.2.4. Diagnostic agreement During the six-month study interval, the residents and faculty members examined successively 171 patients, 89 during the first three months and 82 during the second three months. The agreement of the positive and negative diagnoses was 163/171 (Kappa = 0.89) over the entire six-month period of study. The agreement was 84/89 cases (Kappa = 0.85) in the first three months and 79/82 (Kappa = 0.96) during the second three months. There were 8 instances of diagnostic discordance between the residents and faculty: 5 during the first three months and 3 during the second three months. The exactitude of the diagnosis of the residents was 95.9% (91.8–98; Kappa = 0.90) over the six months, 95.5% (89–98.2; Kappa = 0.88) during the first 3 months and 96.3% (89.8–98.7) (Kappa = 0.92) during the second three months. The sensitivity and the specificity of the residents over the entire six months were, respectively, 91% (80.8–96.8) and 97% (93–99.2). For the first three months, they were, respectively, 90.9 (72.2–97.5) and 97% (89.7–99.2) and 92.6% (76.6–97.9) and 98.2% (90.4–99.7) for the second three months. We did not observe a significant change in the diagnostic accuracy of the residents during the six-month study period (p = 0.06). The faculty members achieved a sensitivity and a specificity during the study period of, respectively, 100% (92.7–100) and 98.3% (94.2–99.5; Kappa = 0.9), and the exactitude of the diagnosis was 98.8% (95.8–99.7).
2.2.1. Sonographic visualization of the appendix The residents visualized the appendix in 118 of the 171 patients (69%), including 78 completely visualized (46%) and 40 partially visualized (23%) (Fig. 2). The appendix was not identified in 53 patients (31%). The faculty members visualized the appendix in 138 cases (81%), including 105 completely visualized (61.4%) and 33 partially visualized (19.33%). The appendix could not be identified in 33 cases (19.3%). The proportions of visualized appendices as well as completely visualized appendices were significantly higher for faculty members than for residents (p = 0.003). 2.2.2. Appendicitis Of the 171 patients studied, 49 had appendicitis, confirmed by pathological analysis, and 122 did not have appendicitis, one of which was confirmed normal at surgery (a 15 years old girl with recurrent right abdominal pain had two ultrasound diagnoses of “appendicitis unlikely” within one week. She finally underwent a laparoscopic operation. An appendix with acute mucosal inflammation in retrocecal position was found.) Senior residents and faculty member have diagnosed 9 complicated appendicitis (2 perforations and 7 abscess) confirmed by surgical and pathological results. In two cases, appendix was not identified during ultrasound examination and CT scan was performed before discharge from the hospital. The two CT scans were interpreted as normal. The other patients were sent home and did not need a followup consultation during the fifteen days that followed the ultrasound. All positive US patients were operated. Surgeons have decided to operate depending mainly on the clinical and ultrasonographical data, and biological data when available. Of the 49 patients with a definite diagnosis of acute appendicitis, 4 (8.1%) were considered as negative by the resident (false negative). One false-positive diagnosis (2%) by ultrasound of appendicitis resulted in an appendectomy. Of the 122 patients
2.2.5. Degree of diagnostic certainty At the completion of each questionnaire, one of four possible diagnoses was chosen: acute appendicitis (A), probable appendicitis (B), appendicitis unlikely (C) and normal appendix (D). In those cases where the diagnoses of both residents and faculty members agreed for acute appendicitis (A) or normal appendix (D), the diagnoses were considered correct. Detailed data are in the Table 1. For the residents, 82 (47.9%) ultrasounds had a diagnosis with a high degree of confidence
Please cite this article as: Gerbier P, et al, Sonography of suspected acute appendicitis in children: Evaluation of the progress in performance of senior residents, J Pediatr Surg (2017), http://dx.doi.org/10.1016/j.jpedsurg.2017.05.013
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Table 1 Percentages of visualization of the appendix, degree of diagnostic certainty and diagnosis. Visualization of the appendix
Senior residents Faculty members
Degree of diagnostic certainty
Diagnosis
Complete visualization
Partial visualization
Non-visualization
Complete visualization
Partial visualization
Non-visualization
Acute appendicitis (A)
Probable appendicitis (B)
Appendicitis unlikely (C)
Normal appendix (D)
78 (45.6%) 105 (61.4%)
40 (23.4%) 33 (19.3%)
53 (31%) 33 (19.3%)
69 (88%) 94 (90%)
13 (33%) 11 (33%)
0 0
35 (20.5%) 40 (23.4%)
13 (7.6%) 11 (6.4%)
76 (44.4%) 55 (32.2%)
47 (27.5%) 65 (38%)
(i.e. diagnosis A or D), for the faculty members, 105 (61.4%). When the appendix was completely visualized, the degree of confidence was 88% for the residents and 90% for the faculty members. With partial visualization of the appendix, the degree of confidence was 33% for both the residents and faculty members. When the appendix could not be identified, the degree of confidence was zero. 3. Discussion Our results have confirmed good diagnostic performance by the residents during the six-month study period. The values for sensitivity (0.92), specificity (0.97), and accuracy (0.96) we obtained for the residents are similar to those reported in meta-analyses [3,12]. We also observed no statistically significant difference between the diagnostic performance achieved by the residents and that of the faculty members. However, we have noticed that the mean duration of ultrasound examination was significantly shorter during the second three-month period. Our study is consistent with an enhanced medical learning cycle that should be “see many, learn from the outcome, do many with supervision and learn from the outcome, and finally teach many with supervision and learn from the outcome.” described by Rohrich [13], which is a new version of the Halsted's model of “see one, do one, teach one.” It emphasizes the capacity of senior residents to be efficient in the ultrasound diagnosis of appendicitis and a progression of their ability during their training. It also provides pedagogical information concerning the utility of a radiological grid with objectives structures to analyze and prompt feedback between surgeons and radiologists. Finally, it also suggests that senior residents had as good ultrasonographic diagnostic skills, as faculty members in the majority of cases. Contributory factors are ultrasound as first imaging procedure for pediatric appendicitis, with a systematic completion of a grid with the sonographic findings and a feedback with radiological-surgical correlation. One falsepositive case of appendicitis was misdiagnosed because of an increase size of the appendix (7 mm). It highlights that the customary upper normal value of 6 mm is probably too sensitive [14]. During our study, the residents had also four false-negative examinations, all corrected by a faculty member upon the subsequent repeat examination. Among these four patients, the appendix was either not visualized at all (1) or only partially visualized (3), but was completely visualized by the faculty radiologist in all four cases, emphasizing the importance of visualization of the appendix by sonography. Secondary signs may also improve the diagnostic accuracy of equivocal ultrasounds for suspected appendicitis in children [15]. In our study, the faculty members were more successful than the residents at visualizing the appendix. The rate of visualization of the appendix by ultrasound has varied widely in the literature. Lee et al. recorded a rate of visualization of the appendix of 99% among patients in all age groups, utilizing a classical approach in the supine position with posterior manual compression [16]. However, this result has not been reproduced by other investigators. Binkovitz et al. visualized the appendix in 49% of cases [17] and did not observe significant differences as a function of patient age, gender, or body mass index (BMI). As in our study, visualization was more frequent in acute appendicitis (75%) than when the appendix was healthy (34%) (p = 0.0001). Moreover, they described an increase in the rate of visualization of the
appendix during the study of 32% the first year of training for the residents with 50.6% the fifth year. Mittal et al. have found a lower rate of visualization of the appendix in the hospitals where ultrasound is used less often or is less available as the first-line imaging examination (25%) compared to hospitals where ultrasound is always available and is routinely employed as the first imaging procedure (56%) [1]. Several authors have shown that specialized pediatric sonographers identified the appendix more often than the general sonographer [10,17]. These reports confirm the importance of experience and the progression of technical competence in sonography that occurs during the course of resident training. In this study, rates of visualization of the appendix were higher than those reported in the majority of the North-American studies. These results could be explained by the fact that ultrasound was performed in a different population by pediatric radiologists, and by residents spending an entire six-month rotation performing only pediatric imaging. That is, the improved performance was partially because of a higher level of medical expertise. Pohl et al. have shown that ultrasound examinations carried out by a sonographer alone had a sensitivity of 26%, compared to 61% for those performed by a sonographer supervised by a radiologist, when diagnosing acute appendicitis in a mixed population of adults and children. They stressed the importance of supervision by an experienced operator [18]. The lack of significant progress of the residents during their six-month rotation could be explained by their already high level of competence with ultrasound in adult patients and, since they were approaching the end of their residency, by their experience in independent diagnostic decision-making. Complicated appendicitis would probably have not influenced the results. Senior residents and faculty members always worked in the same conditions when performing ultrasonographic examinations. The ultrasound grid contained criteria about complicated appendicitis that should always be looked for. It is possible that, with a larger number of study subjects, we might have observed a significant difference in performance between the residents and faculty members, since the latter were more successful in visualizing the appendix in its entirety. The real conditions of training during the residency and the number of patients included over a sixmonth period and during routine working hours constituted limitations to our study. However, if we had included patients over different semesters with different groups of residents we would have encountered greater disparity in the level of competence between inexperienced residents and those nearing the end of their training. We looked for an evaluation of the performance of senior residents, which will work soon independently. It is important to note that the residents in this study have six continuous months of specialized training in pediatric radiology. This is not the case in some other countries where training is limited to three or four fragmented months spread over their entire resident training. 4. Conclusion The sonographic evaluation of suspected acute appendicitis in children, performed by radiology residents nearing the end of their training, was as reliable as that of experienced pediatric radiologist,
Please cite this article as: Gerbier P, et al, Sonography of suspected acute appendicitis in children: Evaluation of the progress in performance of senior residents, J Pediatr Surg (2017), http://dx.doi.org/10.1016/j.jpedsurg.2017.05.013
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with significant shorter examination during the second three months' period. Ultrasound as first-line imaging for suspected pediatric appendicitis associated with a systematic completion of a grid with the sonographic findings and prompt radiological-surgical correlation could help to improve resident performance. Acknowledgements The authors thank Kris Munroe, John C. Scatarige and John Sheath for English language assistance and their friendly support. References [1] Mittal MK, Dayan PS, Macias CG, et al. Performance of ultrasound in the diagnosis of appendicitis in children in a multicenter cohort. Acad Emerg Med 2013;20:697–702. http://dx.doi.org/10.1111/acem.12161. [2] Saucier A, Huang EY, Emeremni CA, et al. Prospective evaluation of a clinical pathway for suspected appendicitis. Pediatrics 2014;133:e88–95. http://dx.doi.org/10. 1542/peds.2013-2208. [3] Doria AS, Moineddin R, Kellenberger CJ, et al. US or CT for diagnosis of appendicitis in children and adults? A meta-analysis. Radiology 2006;241:83–94. http://dx.doi.org/ 10.1148/radiol.2411050913. [4] Sømme S, Bronsert M, Morrato E, et al. Frequency and variety of inpatient pediatric surgical procedures in the United States. Pediatrics 2013;132:e1466–72. http://dx. doi.org/10.1542/peds.2013-1243. [5] Gracey D, McClure MJ. The impact of ultrasound in suspected acute appendicitis. Clin Radiol 2007;62:573–8. http://dx.doi.org/10.1016/j.crad.2006.12.008. [6] Rosen MP, Ding A, Blake MA, et al. ACR Appropriateness Criteria® right lower quadrant pain–suspected appendicitis. J Am Coll Radiol 2011;8:749–55. http://dx.doi.org/ 10.1016/j.jacr.2011.07.010.
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[7] Cundy TP, Gent R, Frauenfelder C, et al. Benchmarking the value of ultrasound for acute appendicitis in children. J Pediatr Surg 2016;51:1939–43. http://dx.doi.org/ 10.1016/j.jpedsurg.2016.09.009. [8] Tiu C-M, Chou Y-H, Chen J-D, et al. Ultrasound diagnosis of acute appendicitis: impact on cost and outcome in pediatric patients. J Med Ultrasound 2004;12:69–74. http://dx.doi.org/10.1016/S0929-6441(09)60067-9. [9] Schuh S, Man C, Cheng A, et al. Predictors of non-diagnostic ultrasound scanning in children with suspected appendicitis. J Pediatr 2011;158:112–8. http://dx.doi.org/ 10.1016/j.jpeds.2010.07.035. [10] Trout AT, Sanchez R, Ladino-Torres MF, et al. A critical evaluation of US for the diagnosis of pediatric acute appendicitis in a real-life setting: how can we improve the diagnostic value of sonography? Pediatr Radiol 2012;42:813–23. http://dx.doi.org/ 10.1007/s00247-012-2358-6. [11] Team RC. R: A language and environment for statistical computing; 2014[Vienna, Austria. URL: http://www.R-project.org/ 2015]. [12] Brennan GDG. Pediatric appendicitis: pathophysiology and appropriate use of diagnostic imaging. CJEM 2006;8:425–32. [13] Rohrich RJ. “See one, do one, teach one”: an old adage with a new twist. Plast Reconstr Surg 2006;118:257–8. http://dx.doi.org/10.1097/01.prs.0000233177. 97881.85. [14] Telesmanich ME, Orth RC, Zhang W, et al. Searching for certainty: findings predictive of appendicitis in equivocal ultrasound exams. Pediatr Radiol 2016;46:1539–45. http://dx.doi.org/10.1007/s00247-016-3645-4. [15] Partain KN, Patel A, Travers C, et al. Secondary signs may improve the diagnostic accuracy of equivocal ultrasounds for suspected appendicitis in children. J Pediatr Surg 2016. http://dx.doi.org/10.1016/j.jpedsurg.2016.03.005. [16] Lee JH, Jeong YK, Park KB, et al. Operator-dependent techniques for graded compression sonography to detect the appendix and diagnose acute appendicitis. AJR Am J Roentgenol 2005;184:91–7. http://dx.doi.org/10.2214/ajr.184.1.01840091. [17] Binkovitz LA, Unsdorfer KML, Thapa P, et al. Pediatric appendiceal ultrasound: accuracy, determinacy and clinical outcomes. Pediatr Radiol 2015;45:1934–44. http://dx. doi.org/10.1007/s00247-015-3432-7. [18] Pohl D, Golub R, Schwartz GE, et al. Appendiceal ultrasonography performed by nonradiologists: does it help in the diagnostic process? J Ultrasound Med 1998; 17:217–21.
Please cite this article as: Gerbier P, et al, Sonography of suspected acute appendicitis in children: Evaluation of the progress in performance of senior residents, J Pediatr Surg (2017), http://dx.doi.org/10.1016/j.jpedsurg.2017.05.013