Detection and Differentiation of Focal Intracranial Calcifications and Chronic Microbleeds Using MRI

Introduction: Differentiating calcification from chronic microbleeds on imaging may have important clinical implications. Aim: The present study aimed to evaluate the role and relative advantages of Magnetic Resonance Imaging (MRI) in the detection and differentiation of intracranial calcifications and chronic microbleeds. Materials and Methods: The retrospective study comprised of 100 patients having either intracranial calcifications or microhaemorrhages selected on the basis of Computerized Tomography (CT) and MRI using predefined criteria. Two independent blinded observers evaluated the images qualitatively and quantitatively. Single pixel values were taken in the circular Region of Interest (ROI) on magnitude SWI, phase Susceptibility Weighted Imaging (SWI) and Diffusion Weighted Imaging (DWI) for quantitative analysis. Results: Fifty patients with 76 focal calcifications and another 50 patients with 245 chronic microbleeds formed part of the study. Overall sensitivity of SWI in detection of calcification was 93.9% with good inter observer agreeability (k= 0.7) on phase SWI. All the chronic microbleeds were seen on SWI but there was only moderate inter observer agreeability in evaluation of signal on phase component (k= 0.5). Average pixel values of calcifications and chronic microbleeds were -312.5±187 SD and 541.9±301.7 SD respectively on phase SWI, (p=0.0001