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Jun 30, 2015 - The relationship between the pathological grades and computed tomography grades was analyzed using Spearman's rank correlation test.

Acute Medicine & Surgery 2016; 3: 21–25

doi: 10.1002/ams2.131

Original Article

Contrast-enhanced multidetector-row computed tomography can predict pathological findings of acute appendicitis in children Naoki Hashizume,1,2 Yasushi Iinuma,1 Yutaka Hirayama,1 Kohju Nitta,1 Hisataka Iida,1 Motoi Shiotani,3 Hiroyuki Shibuya,4 and Minoru Yagi2 Departments of 1Pediatric Surgery, 3Radiology and 4Pathology, Niigata City General Hospital, Niigata City; and 2 Department of Pediatric Surgery, Kurume University School of Medicine, Kurume, Fukuoka, Japan Aims: To retrospectively evaluate the correlation between multidetector-row computed tomography findings of acute appendicitis and the pathological status of acute appendicitis, and evaluate the capability of multidetector-row computed tomography to predict the pathological status of acute appendicitis in children. Methods: The presence of a distended appendix (>6 mm in transverse diameter) was used as a primary sign to indicate the presence of appendiceal inflammation. The presence of appendiceal wall thickening (>1 mm) and enhanced appendiceal wall continuity were also used as predictive findings to reflect the degree of progression of acute appendicitis on multidetector-row computed tomography findings. The findings of each individual case were classified into four grades. The final pathological diagnosis was classified into four groups: normal findings, only mucosal inflammation, inflammation with intramural spreading, and gangrenous. The relationship between the pathological grades and computed tomography grades was analyzed using Spearman’s rank correlation test. Results: Four of six cases in Grade 0 reflected normal appendiceal findings (66.7%) and 3 of 5 cases in Grade I reflected only mucosal inflammation status (60.0%). Forty-four of 51 cases in Grade II reflected intramural inflammation status (86.3%), and 40 of 57 cases in Grade III reflected gangrenous status (70.2%). The multidetector-row computed tomography grade was significantly correlated to the pathological grade with Spearman’s rank correlation coefficient of 0.689 (P < 0.001).

Conclusions: There was a close relationship between the multidetector-row computed tomography imaging findings and the pathological findings. This preoperative information is extremely useful for decision-making in the treatment strategy for acute appendicitis in children. Key words: Acute appendicitis, multidetector-row CT, pathology, pediatrics, radiology

INTRODUCTION

A

CUTE APPENDICITIS (AA) is the most common cause of acute surgical abdomen in children. The diagnosis of AA has traditionally depended on clinical decisionmaking based on the patient’s history and physical examination findings. The signs and symptoms of AA in children, however, often deviate from the classical description; therefore, the use of imaging studies with a high diagnostic accuracy for AA is desirable.1–6

Corresponding: Naoki Hashizume, MD, Department of Pediatric Surgery, Niigata City General Hospital, Shumoku 463-7, Chuo-ku, Niigata City 950-1197, Japan. E-mail: [email protected] Received 17 Dec, 2014; accepted 17 Mar, 2015; online publication 30 June, 2015

© 2015 Japanese Association for Acute Medicine

It is generally accepted that ultrasound (US) is a useful diagnostic tool for detecting AA and has excellent specificity in diagnosing this disease.1 However, US also exhibits variable sensitivity and results with respect to the diagnosis of AA due to its operator-dependent nature. Therefore, the use of computed tomography (CT) has become popular as the initial imaging study for suspected AA in children, especially in emergency settings.2–6 Owing to technological improvements, multidetector-row CT (MDCT) provides comfortable images for review with high accuracy and sensitivity for the diagnosis of AA.7,8 In recent times, although US is the first choice for diagnosis of AA, the time-consuming and operator-dependent nature of US is a significant drawback.4 As CT is not operatordependent and has a high sensitivity and specificity, MDCT was selected for diagnosing AA in our institution. We believe that the capability of MDCT can be used to predict the

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current pathological status of AA. However, there have been no reports describing this relationship in pediatric patients. Therefore, in this study, we studied the correlations between the MDCT findings of AA and the current pathological status of AA and evaluated the efficacy of MDCT in predicting the current pathological status of AA in pediatric patients.

METHODS

T

HE MEDICAL RECORDS of all children under 15 years of age admitted to our institution with a diagnosis of AA between November 2007 and March 2010 were reviewed. A total of 230 children with suspected AA underwent contrast-enhanced MDCT. Of these, 133 children were confirmed with AA and 97 were diagnosed with other diseases. Of 133 patients, 119 (68 boys and 51 girls) underwent appendectomy and 14 were treated with conservative management. The mean age was 10.0 ± 2.81 years, ranging from 4 to 15 years, with a median age of 10 years. All MDCT examinations were carried out using the Somatom Definition AS 64-MDCT system (Somatom Definition Siemens Medical Solutions, Forcheim Germany), with the reconstruction of axial and coronal images measuring 2 mm in thickness. The i.v. bolus injection of 2 mL/kg of iohexol 64% (Omnipaque 300; Daiichi Sankyo Co., Ltd, Tokyo, Japan) was given by a mechanical injector at a rate of 1 mL/s, with a 10-s scanning delay. All images were reviewed using a picture archiving and communication system on liquid crystal display monitors. A board-certified staff radiologist (MS), a fellow trained in general imaging, interpreted all of the obtained MDCT findings in each case. The radiologist was blinded to the outcome of each individual patient. In this study, the presence of a distended appendix (>6 mm in transverse diameter) was assessed as a primary sign of the presence of appendiceal inflammation on MDCT. The degree of appendiceal wall thickening (>1 mm in thickness) and enhanced appendiceal wall continuity was also evaluated as predictive findings reflecting the degree of progression of AA on MDCT. Based on the presence or absence of each of these three factors, the MDCT findings obtained in each individual case were classified into four grades. The criteria for each grade are summarized in Table 1. The typical findings of each grade are also shown in Figure 1. The operative indications of AA referred to the clinical diagnosis of AA were MDCT grade II or III. For patients with MDCT grade 0 or I, conservative management was selected. If the patients with MDCT grade 0 or I and their parents refused conservative management because of long hospital stay and the likelihood of resistance to conserva-

© 2015 Japanese Association for Acute Medicine

Acute Medicine & Surgery 2016; 3: 21–25

Table 1. Criteria of multidetector-row computed tomography (MDCT) grading of acute appendicitis MDCT grade

Appendiceal diameter

Thickness of appendiceal wall

Continuity of appendiceal wall

0 I

≤6 mm >6 mm ≤6 mm >6 mm >6 mm

≤1 mm ≤1 mm >1 mm >1 mm >1 mm

Present Present Present Present Absent

II III

tive management, operative management was selected. Ninety-five patients underwent open appendectomy, and the remaining 24 patients underwent laparoscopic appendectomy. The selection of the operative procedure was made according to the discretion of the attending pediatric surgeon. The median time from MDCT scanning to the initiation of subsequent appendectomy was 4.19 ± 1.90 h (range, 1–10 h). None of the patients used sedation during MDCT. The final postoperative diagnosis of AA was confirmed histologically by a board-certified staff pathologist who was also blinded to the outcome of each individual MDCT grade. The final pathological diagnosis was classified into four groups: normal findings, mucosal inflammation only, inflammation with intramural spreading, and gangrenous findings. In this study, cases of perforated AA were included with those of gangrenous AA. The relationship between the pathological and MDCT grade was analyzed using Spearman’s rank correlation test. A P-value of

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