Distinguishing Tumefactive Demyelinating Lesions from Glioma or Central Nervous System Lymphoma: Added Value of Unenhanced CT Compared with Conventional Contrast-enhanced MR Imaging

Purpose: To determine retrospectively whether unenhanced computed tomographic (CT) images of the brain have added value in distinguishing tumefactive demyelinating lesions (TDLs) from primary glioma or central nervous system (CNS) lymphoma, compared with conventional contrast material–enhanced magnetic resonance (MR) images only. Materials and Methods: This study was approved by the institutional review board, and informed consent was waived. Unenhanced CT and MR images in 15 patients with TDLs (seven women, eight men; mean age, 42 years; range, 27–57 years) and 48 patients with primary brain tumor (27 women, 21 men; mean age, 48 years; range, 19–70 years; 10 lymphomas, 38 gliomas) were retrospectively reviewed. The CT attenuation of regions that were enhanced or unenhanced at MR imaging was visually categorized into three grades, and CT attenuation values were determined quantitatively. The diagnostic accuracy of MR imaging for differentiating TDLs from tumors was compared with that of MR imaging plus CT...