Sampling cerebrospinal fluid via a lumbar puncture (or “spinal tap”) can predict which people with mild cognitive impairment will progress to dementia with over 80% accuracy, but this still means a misdiagnosis for one in five patients. PET scans are slightly less accurate, while routine MRI brain scans can reveal with perhaps only 70% accuracy subtle abnormalities in people with mild cognitive impairment.
通过腰椎穿刺（或“脊椎抽液”）进行脑脊液取样可以预测存在温和认知损伤的人是否会出现痴呆，准确率在80%以上，但这仍然意味着每五人就有一人遭遇误诊。PET扫描准确率略低，而常规的MRI脑部扫描大概只能揭示70%的存在温和认知损伤人士的准确微小异常。