脑囊虫病的MRI诊断

目的：评价脑囊虫病磁共振表现。材料和方法：对9例脑囊虫病MRI回顾性分析。结果：9例中7例可见明显的囊虫结节，1例合并右大脑中动脉闭塞，1例合并蛛网膜下腔囊虫。另2例中，1例表现为白质脱髓鞘改变，1例表现为两顶叶肉芽肿样改变。结论：脑囊虫病分四型、四期。四型包括脑实质型、脑室型、软脑膜型及混合型。四期包括存活期、退变期、坏死期及钙化期。脑实质型MRI较具特征性，可见典型的囊虫结节，即圆形或类圆形、大小约1～10毫米的囊性病灶，其内有偏心或附壁的囊虫头节。存活期囊虫结节MRI表现为囊液T1WI信号与CSF相同，大部分可见偏心或附壁的头节，无囊壁可见，无明显水肿。退变、坏死二期MRI难于区分，此时表现为囊液T1WI信号略高于CSF并随病程延长而信号逐渐增高，囊壁逐渐增厚，一般无头节可见，增强可表现为环状及结节状强化，周围水肿明显。钙化期CT比MR优越。

MRI Diagnosis of Brain Cysticercosis

Purpose: To evaluate the role of MRI in the diagnosis and staging of brain cysticercosis. Materials and Methods: 9 patients with brain cysticercosis evaluated with MRI were retrospectively analyzed. Results:Cysts were seen in 7 cases, including 1 with occlusion of right middle cerebral artery confirmed by DSA and another with one cyst in the subarachnoid space. In the other 2 cases, MRI showed white matter signal alteration and granuloma-like lesion in bilateral parietal lobes respectively. Conclusion: Neurocysticercosis was classified into four types, including parenchymal, ventricular, pial and mixed types, which were subclassified into four stages: alive, degenerative, necrotic and calcified stage. In parenchymal type,characteristic cysts of cysticercosis with 1-10mm in diameter and scolex eccentric in the cyst or inherent to the cyst wall were found on MRI. In alive stage, cyst fluid appeared identical to CSF on T1WI. In most cases, scoleces were seen, no cyst wall could be identified and no surrounding edema. MRI was unable to differentiate degenerative from necrotic stage, on T1WI cyst fluid signal intensity showed slightly higher than CFS and gradually getting higher, simultaneously cyst wall became thickened, frequently, no scolex.Post contrast imaging may exhibit ring-like and nodular enhancement with surrounding edema. In calcification sarge , CT proved to be superior to MRI for the diagnosis.