Discriminating between silent cerebral infarction and deep white matter hyperintensity using combinations of three types of magnetic resonance images: a multicenter observer performance study

Introduction We attempted to determine the most appropriate combination of magnetic resonance (MR) images that can accurately detect and discriminate between asymptomatic infarction and deep white matter hyperintensity (DWMH); these lesions have different clinical implications and are occasionally confused. Materials and methods We performed an observer performance analysis using cerebral MR images of 45 individuals with or without asymptomatic small white matter infarction and/or mild DWMH who participated in a physical checkup program at four institutions. Six observers interpreted whether infarction and/or DWMH existed in combinations of two or three image types of the T1-weighted images (T1WI), T2-weighted images (T2WI), and fluid-attenuated inversion recovery (FLAIR) images. The observers' performance was evaluated with a receiver operating characteristic (ROC) analysis. Results The averaged area under the ROC curve (Az) for detecting a infarction was significantly larger in the combination of all the three image types (0.95) than that in any combinations of the two image types (T1WI and FLAIR images, 0.87; T2WI and FLAIR images, 0.85; T1WI and T2WI, 0.86). The Az for detecting DWMH was significantly smaller in the combination of T1WI and T2WI (0.79) than that in other image combinations (T1WI and FLAIR, 0.89; T2WI and FLAIR, 0.91; T1WI, T2WI, and FLAIR, 0.90). Conclusion The combination of T1WI, T2WI, and FLAIR images is required to accurately detect both small white matter infarction and mild DWMH.