OBJECTIVE: We analyzed the diffusion and perfusion characteristics of acute MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episode) lesions in a large series to investigate the controversial changes of the apparent diffusion coefficient (ADC) that were reported in prior studies. MATERIALS AND METHODS: We analyzed 44 newly appearing lesions during 28 stroke-like episodes in 13 patients with MELAS. We performed a visual assessment of the MR images including the ADC and perfusion maps, comparison of the ADC between the normal and abnormal areas, comparison of % ADC between the 44 MELAS lesions and the 30 acute ischemic infarcts. In addition, the patterns of evolution on follow-up MR images were analyzed. RESULTS: Decreased, increased, and normal ADCs were noted in 16 (36%), 16 (36%), and 12 (27%) lesions, respectively. The mean % ADC was 102 ± 40.9% in the MELAS and 64 ± 17.8% in the acute vascular infarcts (p < 0.001), while perfusion imaging demonstrated hyper-perfusion in six acute MELAS lesions. On follow-up images, resolution, progression, and tissue loss were noted in 10, 4, and 17 lesions, respectively. CONCLUSION: The cytotoxic edema gradually evolves following an acute stroke-like episode in patients with MELAS, and this may overlap with hyper-perfusion and vasogenic edema. The edematous swelling may be reversible or it may evolve to encephalomalacia, suggesting irreversible damage.
OBJECTIVE: We analyzed the diffusion and perfusion characteristics of acute MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episode) lesions in a large series to investigate the controversial changes of the apparent diffusion coefficient (ADC) that were reported in prior studies. MATERIALS AND METHODS: We analyzed 44 newly appearing lesions during 28 stroke-like episodes in 13 patients with MELAS. We performed a visual assessment of the MR images including the ADC and perfusion maps, comparison of the ADC between the normal and abnormal areas, comparison of % ADC between the 44 MELAS lesions and the 30 acute ischemic infarcts. In addition, the patterns of evolution on follow-up MR images were analyzed. RESULTS: Decreased, increased, and normal ADCs were noted in 16 (36%), 16 (36%), and 12 (27%) lesions, respectively. The mean % ADC was 102 ± 40.9% in the MELAS and 64 ± 17.8% in the acute vascular infarcts (p < 0.001), while perfusion imaging demonstrated hyper-perfusion in six acute MELAS lesions. On follow-up images, resolution, progression, and tissue loss were noted in 10, 4, and 17 lesions, respectively. CONCLUSION: The cytotoxic edema gradually evolves following an acute stroke-like episode in patients with MELAS, and this may overlap with hyper-perfusion and vasogenic edema. The edematous swelling may be reversible or it may evolve to encephalomalacia, suggesting irreversible damage.
Authors: T Ohshita; M Oka; Y Imon; C Watanabe; S Katayama; S Yamaguchi; T Kajima; Y Mimori; S Nakamura Journal: Neuroradiology Date: 2000-09 Impact factor: 2.804
Authors: Daniel P Bradley; Justin M Smith; Martin I Smith; Kurt H-J Bockhorst; Nikolas G Papadakis; Laurance D Hall; Andrew A Parsons; Michael F James; Christopher L-H Huang Journal: J Physiol Date: 2002-10-01 Impact factor: 5.182
Authors: C Oppenheim; D Galanaud; Y Samson; M Sahel; D Dormont; B Wechsler; C Marsault Journal: J Neurol Neurosurg Psychiatry Date: 2000-08 Impact factor: 10.154
Authors: Stephen J Kolb; Fiona Costello; Andrew G Lee; Matthew White; Stephen Wong; Eric D Schwartz; Steven R Messé; Jeffrey Ellenbogen; Scott E Kasner; Steven L Galetta Journal: J Neurol Sci Date: 2003-12-15 Impact factor: 3.181
Authors: Dae Chul Jung; Hak Jong Lee; Jin Won Seo; So Yeon Park; Sang Jin Lee; Joo Hyuk Lee; In Hoo Kim Journal: Korean J Radiol Date: 2011-12-23 Impact factor: 3.500