Multi-slice CT diagnosis of early acute appendicitis

Abstract

Objective To investigate the value of multi-slice CT (MSCT) in diagnosing early acute appendicitis (AA).Methods From June 2008 to June 2011,abdomen MSCT images of 41 patients with acute simple appendicitis confirmed by surgery and pathology were evaluated retrospectively. Thirty-six patients with clinically confirmed normal appendix served as the control groups with 18 patients in complicated-normal-appendix (CNA) group and 18 patients in noncomplicated-normal-appendix (NCNA)group. The appendix was reconstructed by using multiplanar reformation (MPR) and curved planar reformation (CPR) techniques. The differences between early AA and normal appendix in appendiceal diameter,thickness of the appendiceal wall, maximum depth of the intraluminal appendiceal fluid (MDIAF), abnormal enhancement of the appendiceal wall, appendicolith and the periappendiceal abnormalities were evaluated and compared by using analysis of variance,R test and Chi-square test.Results The mean thickness of the appendiceal wall was (2.88 ±0.62),(2.58 -±0.50) and (2.73 ±0.53) mm in early AA,CNA and NCNA groups respectively,with no statistically significant difference among them ( F =1.73,P=0.19).The nean appendiceal diameter was (11.37 ± 1.94),(7.03 -±0.89),(6.75 ±0.63) mm,and median MDIAF was 4.05 (2.65-8.50),1.68 (0-.40),0 (0-1.90) mm in early AA,CNA and NCNA groups respectively,with statistically significant differences between early AA and the two normal appendix groups ( Z =7.02,7.24 ; P =0.00 ).The abnormal enhancement of appendiceal wall was found in 61.1％ (11/18) of early AA,16.7％ (3/18) of CNA and 11.1％ (2/18) of NCNA groups respectively,with statistically significant differences between early AA and the two normal appendix groups (x2 =12.83,P =0.00). Using a cutoff value of 7.8 mm of the appendiceal diameter and 2.6 mm of MDIAF for the early AA,the sensitivity,specificity and accuracy were 97.6％ (40/41),91.7％ (33/36) and 94.8％ (73/77),and 100.0％ (36/36),88.9％ (32/36) and 94.4％ (68/72),respectively.Conclusions MSCT is particularly useful for the diagnosis of early AA. When appendiceal diameter is greater than 7.8 mm,and MDIAF greater than 2.6mm,early AA can be diagnosed with confidence. Key words: Appendicitis; Tomography,X-ray computed