Efficacy of Strain Elastography in Diagnosis and Staging of Acute Appendicitis in Pediatric Patients

Abstract

BACKGROUND In the present study, the role and efficiency of strain elastography (SE) were evaluated in diagnosis and staging of acute appendicitis in pediatric patients. MATERIAL AND METHODS We enrolled 225 pediatric patients with suspected clinical and laboratory findings of acute appendicitis. Gray-scale sonographic findings were recorded and staging was made by the colorization method of SE imaging. Appendectomy was performed in all patients and the results of the surgical pathology were compared with the imaging findings. The sensitivity, specificity, and accuracy of SE imaging were determined in terms of evaluating the "acute appendicitis". RESULTS Sonographic evaluation revealed acute appendicitis in 100 patients. Regarding the SE analysis, cases with appendicitis were classified into 3 groups as: mild (n=17), moderate (n=39), and severe (n=44). The pathological evaluation revealed 95 different stages of appendicitis and normal appendix in 5 cases: acute focal (n=10), acute suppurative (n=46), phlegmonous (n=27), and perforated (n=12), regarding the results of surgical pathology. Five patients with pathologically proven "normal" appendix were noted as "mild stage appendicitis" based on gray scale and SE analysis. In total, when gray-scale and SE results were compared with pathology results regardless of the stage of appendicitis, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy rates were 96%, 96%, 95%, 96.8%, and 96%, respectively. No statistically significant difference was detected between other groups (P<0.05). CONCLUSIONS In acute appendicitis, the use of SE imaging as a supportive method for the clinical approach can be useful in diagnosis, and its results are closely correlated with the histopathologic stage of appendix inflammation.

Figure 1

Normal appendix. Normal appendix in the SE (diameter of the appendix 5.1 mm).

Figure 2

Acute focal appendicitis. Lumen with a diameter of 5.6 mm, and a limited blue color-coding in the wall in SE.

Figure 3

Phlegmonous appendicitis. Coding in the SE, with blue color in the central, and with green and blue colors in the periphery.

Figure 4

Suppurative appendicitis. A markedly distended appendix in the SE, and a blue color-coding not exceeding 2 cm in the adjacent fatty tissues.

Figure 5

Perforated appendicitis. A distended appendix with irregular margins in the SE, and a blue color-coding exceeding 2 cm in the surrounding fatty structures.