Atypical appendicitis: diagnostic value of volume-rendered reconstructions obtained with 16-slice multidetector-row CT

Purpose. This study was done to assess the possible clinical value of volume-rendered (VR) and curved volume-rendered (cVR) reconstructions obtained from isotropic data in the diagnosis of atypical appendicitis. Materials and methods. Forty-five patients with suspected acute appendicitis were examined with 16-slice multidetector computed tomography (MDCT) before and after contrast material injection. A diagnosis of atypical appendicitis was made in 33 cases. Two independent blinded radiologists with 2 and 9 years of CT experience assessed the axial scans and 2 months later the VR and cVR reconstructions. The following parameters were considered: presence, location, and wall thickness of the appendix; wall enhancement; distension; periappendiceal fat attenuation; presence of appendicolith; and free air and/or periappendiceal fluid collections. Sensitivity, specificity, and diagnostic accuracy values were calculated for each reader. The concordance between the two radiologists was analysed by using Cohen’s kappa statistic. Results. Mean sensitivity, specificity and accuracy for the less experienced radiologist were, respectively, 82%, 91% and 84% for the axial scans and 94%, 91% and 93% for the VR and cVR images, whereas the values for the more experienced reader were 94%, 100% and 95% for axial scans, and 97%, 100% and 98% for VR and cVR images. Conclusions. In patients with atypical appendicitis, VR and cVR reconstructions increase the accuracy of MDCT in relation to the reader’s experience and reduce the number of false negative results