Accuracy, criteria, and clinical significance of visual assessment on diffusion-weighted imaging and apparent diffusion coefficient quantification for diagnosing acute appendicitis

• Published in: Abdominal imaging Vol. 44; no. 10; pp. 3235 - 3245
• Main Authors: Inoue, Akitoshi, Furukawa, Akira, Nitta, Norihisa, Takaki, Kai, Ota, Shinichi, Zen, Yumi, Kojima, Masatsugu, Akabori, Hiroya, Ohta, Hiroyuki, Mekata, Eiji, Saotome, Takao, Murata, Kiyoshi
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.10.2019; Springer Nature B.V
• Subjects: ABSCESSES; Accuracy; Appendicitis; Appendix; Clinical significance; DIAGNOSIS; Diffusion; Diffusion coefficient; Gastroenterology; Hepatology; Hollow Organ GI; Imaging; Inflammation; Medical diagnosis; Medical imaging; Medicine; Medicine & Public Health; NMR IMAGING; PAIN; PATIENTS; Radiology; RADIOLOGY AND NUCLEAR MEDICINE; Statistical analysis; Tissue analysis; Tissues; Wall thickness; Acute appendicitis; Diffusion-weighted image; Magnetic resonance image; Apparent diffusion coefficient
• ISSN: 2366-004X; 2366-0058; 2366-0058
• DOI: 10.1007/s00261-019-02180-3

Purpose To assess the accuracy, criteria, and clinical significance of diffusion-weighted imaging (DWI) signal intensity and apparent diffusion coefficient (ADC) quantification for diagnosing acute appendicitis. Methods Fifty-one patients with right lower abdominal pain [uncomplicated appendicitis ( n  = 25), complicated appendicitis ( n  = 10), and non-appendicitis ( n  = 16)] who underwent MR examination were enrolled in this retrospective study. Two radiologists independently measured appendiceal diameter and wall thickness. They assessed whether a wall defect, an abscess, extraluminal air, or an appendicolith was present on axial T2WI; evaluated intensity on DWI using a 5-point scale; and determined the ADC values of the appendix and peri-appendiceal tissue. Statistical analysis was performed to assess imaging findings for the diagnosis of appendicitis and complicated appendicitis. Cut-off values were determined using receiver operating characteristic analysis. Results For diagnosing acute appendicitis, the accuracy improved from 78.4% using only T2WI to 86.3% using combined T2WI and DWI for reader 1 and from 82.4 to 86.3% for reader 2. For the appendix, the cut-off ADC values that diagnosed appendicitis were 1.41 × 10 −3 and 1.26 × 10 −3 mm 2 /s with accuracies of 78.4% and 76.5%, respectively. For the peri-appendiceal tissue, these values of 1.03 × 10 −3 and 0.91 × 10 −3 mm 2 /s differentiated between uncomplicated and complicated appendicitis with an accuracy of 97.1%. Conclusions Combined DWI and T2WI provided high accuracy for diagnosing appendicitis. The inflamed appendix had lower ADC value than the normal appendix. The peri-appendiceal tissue presenting low ADC value was a notable finding of complicated appendicitis.