Diagnostic Imaging of Patients in a Memory Clinic: Comparison of MR Imaging and 64–Detector Row CT

Abstract

To investigate the assessment of global cortical atrophy (GCA), medial temporal lobe atrophy (MTA), and white matter changes (WMCs) in patients screened at a memory clinic with a 64-detector row computed tomography (CT) brain protocol, in comparison with the reference standard, magnetic resonance (MR) imaging. The study protocol was approved by the local institutional review board. Written informed consent was obtained from all participants. Thirty patients (21 men, nine women; median age, 62 years) who presented to a memory clinic underwent 64-detector row CT and multisequence MR imaging of the brain on the same day. Three readers blinded to the clinical diagnosis assessed the resultant images. Images were presented in random order and scored for GCA, MTA, and WMC with published visual rating scales. Intermodality agreement between CT and MR imaging (intrareader agreement across both modalities), expressed by weighted kappa analysis, and interobserver agreement within each modality between readers (Kendall W test) were assessed. Overall, excellent intraobserver agreement between CT and MR imaging was observed for GCA (mean kappa, 0.83) and MTA (mean kappa, 0.88 and 0.86 on the left and right sides of the brain, respectively). There was substantial overall agreement concerning WMC (mean kappa, 0.79). For all three tested scales, interobserver variability was low and comparable for CT and MR imaging. Use of 64-detector row brain CT yields reliable information that is comparable with that obtained with MR imaging. Thus, multidetector row CT is a suitable diagnostic imaging tool in a memory clinic setting.