Enhancement dynamics of tumefactive demyelinating lesions on brain MRI associated with clinical course

      Objectives: The evolutionary characteristics of the lesions of tumefactive demyelinating lesions (TDL) on contrast-enhanced T1-weighted images, were evaluated and summarized to facilitate the diagnosis of TDL.
      Methods: The brain MRI imagings of 60 patients pathologically diagnosed with TDL (≥20 mm in diameter) were assessed. The course of the disorder was classified as acute phase (≤2 weeks), subacute phase (>2 weeks, but ≤6 weeks), and chronic phase (≥7 weeks) according to its clinical course.
      Results: (1) The diameters of lesions ranged 21–85 mm, and the mean diameter was 45 ± 22 mm. (2) We summarized the neuroimaging features of TDL on MRI in different clinical phases as the following: a) For acute phase (≤2 weeks), the images of contrast enhancement brain MRI were available for 18 cases. In 17 of the 18 cases, their images showed variable degrees of contrast enhancement. The patterns of enhancement were patchy (n = 5), nodular (n = 7), complete ring (n = 3), open ring (n = 4), flame-like (n = 2) and dilated venular (n = 3). b) For subacute phase (3–6 weeks), contrast enhancement MRI images were available for 54 cases. 52 of the 54 cases showed marked contrast enhancement and patterns of enhancement were open ring-like (n = 18), complete ring-like (n = 14), irregular round (n = 18), patchy (n = 21), nodular (n = 8), flame-like (n = 5) and dilated venular in a dense array (n = 25). c) For chronic phase (≥7 weeks), contrast enhancement MRI were available for 28 cases. 13 of the 28 cases showed mild contrast enhancement, such as mild patchy (n = 8), open ring-like (n = 4), and complete ring-like (n = 4).
      Conclusion: Different manifestations of the lesions on contrast-enhanced MRI develop in different clinical stages of TDL. Dynamic evolution of the enhanced MRI may be more important to facilitate the diagnosis of TDL.