脊髓亚急性联合变性ppt素材.pptVIP

其它维生素缺乏病 手术病理：瘤内见明显胶质样物，镜下见大量角化物及少许鳞状上皮 诊断：左颞叶胆脂瘤 胆脂瘤 又称表皮样囊肿，好发于CPA和鞍上池，CT扫描低密度，MR以较均匀T1低信号、T2高信号为主。见缝就钻，增强扫描无强化。 脑内胆脂瘤 较少见，多数位于额、颞叶。 MR信号：根据瘤内成分种类及含量不同而异。 典型胆脂瘤：以不均匀T1低、T2高信号为主。DWI高信号，增强扫描无或边缘强化。 不典型胆脂瘤：以T1高、T2低信号为主，可能与高蛋白成分有关，也有其它解释。 鉴别诊断 典型信号病变（长T1长T2）：胶质瘤、畸胎瘤，DWI高信号、增强扫描无强化等有助鉴别。 不典型信号病变（短T1长T2）：脑出血，肿瘤或血管畸形并出血。 中枢神经少见疾病影像诊断思路 仔细观察病灶的影像形态，结合临床作诊断 掌握新进展，并与临床实践结合。 重视病例随访，不断积累经验。 THANKS * N20:又称笑气，无色有甜味气体 。早期被用于牙科手术的麻醉，是人类最早应用于医疗的麻醉剂之一。在室温下稳定，有轻微麻醉作用，并能致人发笑。现在主要用于表演。 * namely the spinal cord must have been irradiated, the injured segment of the spinal cord must have been in the irradiated field and cord compression must be Excluded (a) Sagittal turbo spin echo (TSE) T2-weighted image shows expansion of the cervical cord and the medulla oblongata with diffuse high signal. (b) Sagittal T1-weighted image shows fatty vertebral body marrow signal with cord expansion. (c) Gadolinium-enhanced sagittal T1-weighted image showed an area of ring enhancement within the cord indicating a breakdown in the blood–central nervous system barrier (d) Sagittal TSE T2-weighted images (study carried out 1 year later to (a), (b) and (c)) shows cord atrophy and no residual high signal. * (a) Sagittal turbo spin echo (TSE) T2-weighted image of the cervical and thoracic spine showing multiple high signal, predominantly ovoid lesions with a longitudinal orientation. These lesions are predominantly in the cervical region and do not extend over more than two vertebral bodies in length. (b) Axial TSE T2-weighted image demonstrates a lesion that lies in the left posterior-lateral region of the cord involving both grey and white matter. (c) Gadolinium-enhanced T1-weighted image demonstrates enhancement in several, but not all of the high T2 signal foci. There is minor cord expansion. predominantly in the dorsal and lateral columns The lesions are usually longitudinally oriented with length ranging from 2 to 60 mm and width usually less than half the diameter of the cord ，predominantly in